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Page 1: Communicate Issue50
Page 2: Communicate Issue50

HU

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TEJU

N 2009 ISSU

E 50

Page 3: Communicate Issue50

JUN 2009 ISSUE 50

HU

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TEJU

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LTE requirementsfor bearer networks

IPTime powers mobile broadband

SFR: convergence and synergies

Turkcell moving towards a connected world

New power with the new PTNChina Mobile’s PTN construction in Zhejiang

Page 4: Communicate Issue50
Page 5: Communicate Issue50

Sponsor: Huawei COMMUNICATE Editorial Board,Huawei Technologies Co., Ltd.

Consultants: Hu Houkun, Xu Zhijun, Xu Wenwei, Tao Jingwen Ding Yun, Yu Xiangping, He Ming

Editor-in -Chief: Gao Xianrui ([email protected])

Editors: Xue Hua, Li Xuefeng, Liu Zhonglin, Huang Zhuojian Zhou Huajiao, Fan Ruijuan, Chen YuhongXu Ping, Xu Peng, Pan Tao, Yao HaifeiMike Bossick, Gary Maidment, Zhou Shumin

Contributors: Zhu Yonggang, Li Weishi, You Yiyong, Cai ChangtianGao Ji, Tang Xinbing, Ma Yanfeng, Chen Jianyun Zhou Xiao, Bian Mingang, Hu Chang, Xie Yong Zhai Junhui, Xie Juan, Li Bing, Peng Kuncheng Liu Dongfeng, Sun Qiang, Sun Ao, Kamil Sahin

E-mail: [email protected]

Tel: +86 755 28780808

Fax: +86 755 28356180

Address: A10, Huawei Industrial Base, Bantian, Longgang, Shenzhen, China 518129

Publication registration No.: Yue B No.10148

The information contained in this document is for reference purpose only, and is subject to change or withdrawal according to specific customer requirements and conditions.

Copyright © Huawei Technologies Co., Ltd. 2009. All rights reserved.No part of this document may be reproduced or transmitted in any form or by any means without prior written consent of Huawei Technologies Co., Ltd.

NO WARRANTYThe contents of this document are for information purpose only, and provided “as is”. Except as required by applicable laws, no warranties of any kind, either express or implied, including but not limited to, the implied warranties of merchantability and fitness for a particular purpose, are made in relation to contents of this document. To the maximum extent permitted by applicable law, in no case shall huawei technologies co., ltd be liable for any special, incidental, indirect, or consequential damages, or lost profits, business, revenue, data, goodwill or anticipated savings arising out of or in connection with any use of this document.

High-speed 3G and LTE data services are destined to offer a ubiquitous wireless broadband experience and create tremendous market opportunities for operators. This potential can be tapped to offset the slow growth in ARPU and the increasingly intense competition in the full service 3G era, which is delivering both challenges and opportunities. The IP-based mobile bearer network forms a network support system and a burgeoning trend in the industry. Moreover, it represents a key developmental direction by which operators can decisively face the wealth of difficulties presently characterizing the industry.

The evolution to packet-based mobile bearer networks has gathered momentum and has attracted leading operators such as Vodafone, France Telecom, MegaFon, and China Mobile. Each is continuing to broaden the horizon for the development of mobile bearer networks by staying at the forefront of innovation. Nevertheless, the transition to packet-based mobile bearer networks is a challenging path in which technical evolution cannot be accomplished at a stroke and for which numerous questions must be first addressed.

How can existing investment be effectively protected? While mobile broadband will doubtlessly boom, voice remains a leading source of mobile network revenue. Additionally, 2G, 3G, and LTE networks will coexist over the long term, which requires the strong access, compatibility, and expansion capabilities of mobile bearer networks.

How can carrier-class packet services be ensured? TDM and ATM technologies are noted for their carrier-class performance, but packet network still has certain difficulties to overcome. Packet technology in the 3G era must incorporate a new “gene” to match the 3G/LTE carrier-class operation requirements that relate to security, QoS, and time synchronization.

How can network O&M be simplified? The IP network “cloud” has greatly increased networking flexibility, but has also raised O&M costs. Expectations are high for reducing O&M complexity over IP networks when 3G/LTE services are based on IP architecture.

Focusing on mobile bearer, this issue of COMMUNICATE explores topics related to packet, broadband and evolution of bearer network, and aims to identify a successful operational approach.

As a reliable partner for operators and with extensive experience in global network deployment, Huawei has developed an end-to-end IPTime mobile bearer network solution underpinned by the industry’s most comprehensive product portfolio. It is our vision to help operators achieve greater success in mobile bearer networking and fully exploit the opportunities prevalent in the full service operation.

Mobile bearer rises to changes

Ding Yun

President of Huawei Network Product Line

Page 6: Communicate Issue50

What’s inside:

Cover Story

11 New power with the new PTNChina Mobile’s PTN construction in Zhejiang

As a pioneer in full service operation and 3G network construction, China Mobile Zhejiang’s mission to raise its market equity is coming into focus after selecting the optimum technology for its bearer network.

By Lv Lingling

P.11 P.01

04 Huawei and TeliaSonera achieve world’s first LTE mobile broadband connection

Global Digest

01 3 launches UK’s best value “one-month” mobile broadband plan

Main Topic

17 PTN ushers in the future of IP service transport

By Bill Huang & Li Han

22 Find the right pitchAnalysis on different mobile bearer network strategies

By Bian Mingang

25 Backhaul technology in the IP eraBy Liu Xiheng

27 IP backhaul for FMCBy Liu Dong

09 Moving towards a connected world

In his keynote speech at the MWC 2009, Sureyya Ciliv, Turkcell’s CEO, described how the world is transforming into a connected world, and explained how Turkcell plans to retain its successful market position.

By Sureyya Ciliv, CEO of Turkcell

Voice from Operators

05 SFR: 1+1>2The new SFR is aiming to be “the biggest, strongest non-incumbent in Europe.” Mr. Pierre-Alain Allemand, Senior EVP of SFR elaborated on how the company is transforming networks to achieve convergence, synergy and reach their lofty goals.

By Julia Yao

Page 7: Communicate Issue50

P.18P.16P.43

Let’s COMMUNICATE beyond technology and share understandings of the latest industry trends,

successful operational cases, leading technologies and more. Based on in-depth analysis of the

matters that lie close to your heart, we will help you stay on top in the competitive telecom industry.

47 When microwave meets the IP waveBy Li Jiangling

40 Choosing the right technology for mobile backhaul evolution

By Ma Hongzhong

32 Enabling easy mobile bearer O&MBy Cui Jinguo

49 LTE requirements for bearer networksAs increasing numbers of leading operators unveil their LTE plans, the high requirements for LTE are shaping the development of bearer network technology.

By Du Wei

37 IPTime powers mobile broadbandBy Li Hongsong

Solution

35 OAM in the IP bearer eraInterview with Boris You, President of the Huawei Network OSS and Service Product Line

Interview

43 Latest developments of PTN standardsFind out more about the latest developments in the two standards of packet transport network (PTN) technologies: T-MPLS/MPLS-TP and PBB-TE.

By Zhang Haiyan

Leading Edge

29 Mobile backhaul strategies for emerging marketsEmerging markets have become an intense battleground for multinational mobile operators with their strategy to enlarge their global footprint. These operators are facing enormous challenges to build the backhaul networks with their TCO efficient and quick time-to-market strategy.

By Madhav Bhatta

How to Operate

Page 8: Communicate Issue50

GLOBAL DIGEST

JUN 2009 . ISSUE 501

News

BT ups broadband speeds to 20Mbps

BT has announced that it will

offer more than double the highest

level of speed available to both its

residential and business customers.

The operator revealed that, having

enabled 549 exchanges for ADSL2+

services, the speed increase will initially

be made available to businesses on an

immediate basis; residential subscribers

will be upgraded in the summer.

BT claims that its initial coverage

for the service will allow it to reach

approximately ten million homes and

businesses, representing around 40%

of the country population. It expects

this to rise to 55% coverage by March

2010. The speed upgrades will be

free and automatic, the operator has

revealed, and as well as an increase in

download speeds, upload speeds will

rise to up to 1Mbps.

BT has also said that it plans

to commence trials of its 40Mbps

superfast fibre-based broadband in

Whitchurch, South Wales and Muswell

Hill, London.

Verizon sells landline business

Verizon Communications announced

plans to sell its landline phone

business to Frontier Communications.

According to a Verizon spokesperson,

Verizon is selling its entire landline

business in West Virginia, Ohio, and

12 other states (including parts of

California).

This transaction will allow Verizon

to focus more on its wireless, fiber-

based wireless, and global Internet

protocol networks. It's also expected

to strengthen Frontier's position

as a premier rural communications

provider and return 8.6 billion USD to

Verizon and its shareholders.

Orange introduces first ever £5 a month mobile tariff

Orange has announced that it is

extending its Pay Monthly (PAYM)

range to include a £5 tariff, the

lowest contract price point on the

market, alongside new £10 and £15

monthly plans.

Available from 1st June 2009,

these 36 month great value plans

prov ide customers with two

handsets–one when they sign up and

another after 18 months. Orange will

also introduce 18 month SIM Only

contracts for the first time which

provide customers with more inclusive

minutes and text messages offering

better value than ever before.

3 launches UK’s best value “one-month”s mobile broadband plan

Britain’s biggest mobile broad-

band network 3 brings you Britain’s

most flexible and affordable contract

with just a 1 month commitment.

“Broadband 5GB 1 month”

provides customers with a 3

Mobile Broadband sim complete

with 5GB of data for just £15 a

month to use with their existing

3 dongle. 5GB is enough to send

5,000 emails or about 50 hours of

web surfing.

And far from asking for the

standard 12, 18 or 24 month minimum

term required by most Mobile

Broadband deals, “Broadband 5GB

1 month” is a 1 month contract.

After that, consumers can cancel by

giving just 30 days notice.

The offer is perfect for customers

wishing to upgrade their Pay As You

Go Mobile Broadband packages

to Pay Monthly but fearful of the

contract commitment, and they

don’t even need to invest in a brand

new 3 dongle.

Globe ups wireless broadband coverage to meet demand

Filipino telco Globe Telecom

has expanded its wireless broad-

band coverage to meet rising

demand in the country. According

to a repor t f rom As iaPu l se ,

Menchi T. Orlina, Globe's head for

consumer marketing group, said

the operator is spending heavily

and aggressively to improve both

broadband penetration and its

position in the market. Orlina

forecasts the country’s potential

market for wi re less Internet

broadband could top 20 million

subscribers by 2012. In order to

capitalise on this she says Globe is

offering Globe Broadband Tatoo –

a WCDMA/HSDPA service offering

download speeds of up to 2Mbps

– and Globe Broadband Powered

by WiMAX.

Globe’s WiMAX network is

based on the 802.16e standard and

operates in the 2.5GHz band. It is

currently available in selected areas

in South Luzon, National Capital

Region, Visayas and Mindanao.

Around 4,000 users are signed up

to the service, Orlina said.

T-Mobile UK receives highest wireless broadband satisfaction ratings

T-Mobile UK received the highest

overall customer satisfaction ratings

in a recent survey of 2,083 British

wireless broadband users.

The independent YouGov study

found that T-Mobile was ahead of

the competition in terms of network

coverage (reflecting the company’s

substantial investment in this area),

as well as ease-of-use, installation,

and billing. The company tied for first

place in the area of customer service.

“As Internet access from any

location continues to rise up the

priority list for our customers, we aim

to provide them with total freedom

to check emails, surf the Internet

and share photos,” commented

Richard Warmsley, head of T-Mobile’s

Internet and entertainment division.

Areas where T-Mobile fell short

of the #1 ranking include upload/

download speeds, and value for

money.

Page 9: Communicate Issue50

JUN 2009 . ISSUE 50 2

Data

100 millionPyramid Research is expecting

LTE networks to grow more rapidly

than their 3G antecedents, with 100

million subscribers expected on the

proto-4G technology in just four

years.

18Google has disclosed that by the

end of 2009 it expects at least 18

phones on the market running its

Android operating system. That number

does not include handset makers using

the basic version of Android that have

not notified Google of their plans.

Andy Rubin, Google's director of

mobile platforms, said the number

could be as high as 20, and that the

phones will be made by eight or nine

handset makers.

30 millionChina Unicom ant ic ipates

signing up 20 million to 30 million

WCDMA users within a year of

launch, according to the operator's

Vice President Zhang Jun'an.

Zhang added that the three

mainland cellcos (China Unicom,

China Mobile and China Telecom)

plan to get 150 million 3G users in

three years.

678.8 millionChina has ended April with a

total of 678.8 million mobile users,

up 1.26 percent from the previous

month and up 16.33 percent year-

on-year. The user density at end-

April was 50.7 percent. During April,

mobile users sent 60.25 billion SMS

messages, averaging 2.98 message

per subscription per day. Furthermore,

some 333.21 million Chinese had a

land-line subscription, representing

25.3 percent of the population.

126Total contracts awarded within the

wireless industry for Q1 reached 126,

just down slightly from Q1 2008 levels

according to the latest report from EJL

Wireless Research.

The base station contract analysis

reports are issued on a quarterly and

annual basis and provide a unique

perspective on the global cellular/

PCS base station contract awards

and demand for mobile base station

equipment covering all major suppliers.

40%Apple's iPhone device accounted

for just 8% of smartphone shipments

last year, but its users are already

responsible for 40% of mobile Internet

usage, according to AdMob's recent

Mobile Metrics Report.

That puts the iPhone far ahead

of Symbian-based devices, which

made up 52% of the g loba l

smartphone market in 2008, but

accounted for only 26% of mobile

web traffic.

T-Mobile tests LTE

T-Mobile Austria has installed

a trial LTE network in its Vienna

Rennweg store, to showcase the

technology. T-Mobile contracted

Huawei as the technical partner and

equipment supplier for the project.

J im Burke, chief technical

officer, said, "from our perspective,

we present in this showcase two

world premieres; for the first time a

speed of over 130Mbps over the air

interface has been reached, with four

modems simultaneously active in a

cellphone." T-Mobile has called for the

Austrian government to consider the

distribution of 2.6GHz frequencies,

so it can prepare to launch the

technology on a commercial basis.

Vodacom South Africa trials location-based advertising

South Africa's mobile operator

Vodacom has launched a new

location-based advertising offering.

The location-specific advertising is

currently being trialed on Vodacom's

mobile social network–The Grid.

The ads are delivered based on

a user's (mobile phone) location.

The ads are delivered within a 10km

radius of the user, making it possible

to promote a special offer available

at a specific store. Through the

new Grid website, location-specific

banner ads are delivered to a user's

dashboard once logged in.

A web-based location targeted

ad will tell a user how far they are

from the store's physical location,

for example "this is a location-based

ad approximately 283m from you".

Once a user clicks on the ads they

are taken through to the location of

that store on a Grid map. The ads are

charged on a cost-per-click model,

making it affordable and possible for

companies and brands to tailor their

advertising needs specific to different

stores or promotions.

AT&T to deploy LTE in 2011

AT&T Mob i l i t y w i l l beg in

upgrading its HSPA network to

allow for theoretical peak downlink

speeds of 7.2Mbps starting later

2009, and expects to complete the

work by 2011. It has also brought

forward its LTE rollout plan, testing

to start in 2010 and deployment in

2011.

The operator said it would

double the amount of 850MHz

wireless spectrum used for its 3G

network in most metropolitan

areas, and will offer multiple HSPA

7.2Mbps-compatible laptop cards

and smartphones starting later this

year.

In addition, it will add more

cell sites–2,100 across the United

States–and increase bandwidth in

its cell sites by adding fiber-optic

connections between the sites

and its IP backbone network. The

company also said it will begin

trialling 3G microcell offerings, which

use femtocells to enhance in-building

wireless coverage.

Page 10: Communicate Issue50

GLOBAL DIGEST

JUN 2009 . ISSUE 503

Huawei News

Huawei launches industry’s first EasyGSM BTS for rural areas

Shenzhen, China, 27 May 2009,

Huawei has launched a 2G base

station designed for use in rural

communities in developing markets

The "EasyGSM BTS" is the

industry's first All-IP-based compact

BTS, and is specifically designed

for rural areas. The BTS represents

another innovative product designed

and developed in close collaboration

with Vodafone in the two firms'

joint Radio Mobile Innovation Centre

based in Madrid, Spain.

"Huawei is pleased to have

collaborated closely with Vodafone

to deliver innovation to Vodafone's

emerging markets, making mobile

communications affordable to

rural communities," said He Gang,

President of Huawei GSM&UMTS

Product Line. "Through its strategic

partnership with Vodafone, Huawei

has a proven track record in

combining technological expertise

with customer-dr iven serv ice

capabilities. We've played a role in

strengthening Vodafone's leading

market position while at the same

time, further building on our product

portfol io–the broadest in the

industry."

Vodafone has completed first

trials of Huawei's new base station,

and is reviewing options for a

commercial launch.

With a volume of just 12 litres

and weighing just 12kgs, the

EasyGSM BTS can be mounted

on a pole, wall, or tower, making

installation quick and easy. It also

offers low power consumption

ideally suited to onsite green energy

generation.

Huawei launches world’s first commercially-ready 4T4R WiMAX distributed base station

Shenzhen, China, 9 June 2009,

Huawei announced the launch

of the world's first commercial

WiMAX distributed base station

(DBS) with 4T4R (four transmitters

and four receivers) features.

With the enhanced coverage

capabilities and capacity of the

new 4T4R WiMAX DBS, operators

will be able to reduce the number

of base station sites in certain

areas and lower their total cost

of ownership. The 4T4R WiMAX

DBS w i l l i nc rease opera t ion

efficiency by supporting multi-

standard convergence. It can also

be configured into two 2T2R base

stations which will enable the 4T4R

WiMAX DBS to handle different

coverage configurations.

Huawei ' s s ta te-of - the-ar t

4T4R WiMAX DBS is based on

Huawei's 4th-generation BTS

platform, and also incorporates

green technologies such as natural

cooling and a high efficiency

power amplifier. This allows for

the 4T4R WiMAX DBS to greatly

reduce the energy consumption

and achieve better cost efficiency.

Huawei bags three prestigious Asia Pacific telecom awards from Frost & Sullivan

Singapore, 5 June 2009, Huawei

announced that it has been named

as Asia Pacific's 2009 Wireless

Infrastructure Vendor of the Year,

Broadband Equipment Vendor of

the Year, and Vendor of the Year by

Frost & Sullivan for its exceptional

business performance for the year

2008. Huawei is the only company

to have received three awards

at the 2009 Frost & Sullivan Asia

Pacific ICT Awards.

Frost & Sullivan Senior Industry

Ana lys t M. Kumaresan sa id :

"Huawei Technologies has been at

the forefront of the wireless and

fixed telecom equipment industry

with cutting-edge products and

extended emphasis on R&D. This is

evident from some of the products

that the firm introduced in 2008

in Asia Pacific, namely the Single

RAN technology, co-platform

products and an emphasis on IP-

related solutions. The awards are a

testament to Huawei's leadership in

the region as an end-to-end vendor

offering next-generation wireless

and wireline services and solutions

to its customers."

Commenting on the awards,

Mr. Wan Biao, President of Huawei

Wire less Product L ine , sa id :

"We are very pleased with this

recognition of our contribution to

the development of the industry.

Our success is driven, in large part,

by our ability to respond quickly in

meeting our customers' business

cha l l enges w i th techno logy

solutions that integrate innovation,

quality, and value. Our goal is to

provide universal and best mobile

broadband service and create

maximum value for our customers."

Huawei ships 1 million umts transceivers

Shenzhen, China, 14 May 2009,

Huawei announced that it has now

shipped 1 million transceivers (TRXs)

for UMTS base stations to operators

all over the world. Huawei's millionth

TRX was recently delivered to China

Unicom.

During the first quarter of 2009,

the number of shipments of Huawei

TRXs for UMTS base stations reached

257,000 – up more than 200 percent

year-over-year. The company has also

secured 139 UMTS/HSPA commercial

contracts in about 100 countries and

regions by the end of March.

Mr. Wan Biao, President of

Huawei Wireless Product Line, said:

"During our 11 years of research and

development in UMTS, we have seen

an increasing number of leading

operators that have partnered with

Huawei. Through our future-oriented

networks constructed on an IP-

based convergent mobile broadband

platform, Huawei is committed to

offering customized solutions to

operators worldwide and helping

them to achieve business growth."

Page 11: Communicate Issue50

JUN 2009 . ISSUE 50 4

Huawei and TeliaSonera achieve world’s first LTE mobile broadband connection

Oslo, Norway, 4 June 2009,

Huawei and TeliaSonera/Netcom,

announced the world's first mobile

broadband Internet connection over

a live commercial LTE network in Oslo,

Norway.

Mr. August Baumann, President

of Netcom (subsidiary of TeliaSonera

in Norway) says: "We appreciate the

professional implementation from

Huawei and we are very pleased to

make this world's first LTE session

in Norway. This demonstration saw

download speeds to mobile devices

greater than what is currently available.

Based on Huawei's LTE solution,

TeliaSonera's LTE network will benefit

from high quality and extensive capacity

to provide end users with the best

mobile communication experience.

The first showcase on the live LTE

network in Oslo, between a laptop PC

with a 4G modem and public Internet/

Intranet included downloading of high

resolution photos, music, movies and

mobile business applications, at a speed

much quicker than most available fixed

Internet accesses of today.

By adopting the LTE MIMO and

OFDM technologies (Multiple Input

Multiple Output and Orthogonal

Frequency Division Multiplex, key radio

technologies of LTE), the download

peak data rate can reach 150Mbps in

one LTE cell with multiple terminals.

Huawei and Portugal Telecom in the development of the biggest FTTH network in Portugal

Lisbon, Portugal, 25 May 2009,

Huawei announced that it has been

selected by Portugal Telecom for the

development of the its Fiber-to-the-

Home (FTTH) network in Portugal.

Since 2007 Huawei, in collabo-

ration with Portugal Telecom, has

been developing laboratory tests

and field trials with the objective of

supplying new generation optical

technology for the access network

in Portugal. These tests are based on

new Gigabit Passive Optical Network

(GPON) technology.

This project will allow Portugal

Telecom to provide the Portuguese

market with the most advanced

access technology. Under the

commercial offering Meo, Portugal

Telecom is currently providing the

new concept of television services

based on IPTV. The development

of the FTTH network will allow the

operator to increase the efficiency

and quality of these services and

provide for example High Definition

IPTV, enhanced high speed Internet

and advanced IP telephone services.

At the same time, the operator

will be able to increase its number

of subscribers and develop new

services for the future.

"This new network that Portugal

Telecom is implementing will allow

the access to the highest debits

and high reliability services and will

fulfill the growing demand of our

customers," explains Mr. Zeinal

Bava, CEO of PT Group. "It will

create a new way of working and

will lead into a new era for creation,

innovation and cooperation."

Huawei and KPN co-host Core Network User Group Conference in Amsterdam

Amsterdam, The Netherlands,

15 May 2009, Huawei and KPN,

the incumbent operator in The

Netherlands, co-hosted the first Core

Network User Group Conference in

Amsterdam. Over 100 people from

operators such as KPN, Orange,

T-Mobile, Vodafone, Etisalat, AIS,

MTS, MegaFon, China Mobile

and their subsidiaries attended the

3-day conference from May 5–7.

Customers exchanged information on

best practices and were given details

of upcoming product enhancements

by Huawei senior management.

"Customer is the only reason

that Huawei exists." said Dr. Wang

Chenglu, R&D President of Huawei

Core Network Product Line in his

address, "Support from customers

is crit ical to our success. The

interaction with so many leading

operators in this forum will allow us

to improve our solutions and service

quality to bolster your business

success. Core networks are very

complex, but we have confidence

that we can deliver good solutions

based on customer requirements

and close cooperation."

"The capacity of our circuit

switched (CS) network needed to

be expanded due to traffic growth,

existing network elements were old,

and we aimed at the introduction

of a layered architecture while

integrating two operator networks

at the same time," as recalled

by Paul Peppelman, Network

Tran s fo rma t i on P rog ramme

Manager of KPN, "We decided to

modernize our core network with

Huawei's state of the art solution

while using standardized interfaces."

He detailed the complex process

which was successfully executed to

implement a new Huawei 2G/3G

unified core network.

Huawei's mobile softswitch

p re sen t s many advan tages .

I t enables customers to save

CAPEX&OPEX, have new features,

create an opportunity to clean up

old proprietary solutions and build

a future that includes a full IMS

based All-IP FMC (Fixed Mobile

Convergence) network. At the

end of Q1 2009, Huawei's mobile

softswitch systems and packet

switched (PS) systems are serving

over 1.33 billion subscribers and 240

million subscribers, respectively.

Page 12: Communicate Issue50

JUN 2009 . ISSUE 50

Towards convergencehe new SFR, now fully-fledged with both mobile and fixed capabilities, is in a strong position to develop strategies built around fixed-

mobile convergence. How does SFR define convergence based on its understanding of consumer needs?

COMMUNICATE: In your view, what are the latest customer needs and service trends for converged services in the French telecom market?

Mr. Allemand: The SFR group, the second largest carrier in France, is a major player with strong expertise and a footprint in both mobile and fixed markets. Our understanding of the French customers’ requirements regarding convergent services is the ability of the customer to experience the same services, voice or data, in a seamless manner, whatever the telecommunication media used.

Also interesting is the need for more simplicity of use and less technological complexity. For instance, the customer doesn’t want to reconfigure the voice mail or the contact book just because he/she is using it from home, from the office or while walking on the street. This means

By Julia Yao

SFR: 1+1>2

5

SFR is the second largest mobile operator in France and in 2008, acquired Neuf Cegetel, the leading alternative fixed operator. SFR’s market share is at an all-time high, now covering all market segments with over €12 billion revenues and they are the number one fixed and integrated alternative carrier in France. According to their mission statement, SFR is aiming to be “the biggest, strongest non-incumbent in Europe.” In an exclusive interview with COMMUNICATE, Mr. Pierre-Alain Allemand, Senior Executive Vice President of SFR elaborated on how the new SFR is transforming networks to achieve convergence, synergy and reach their lofty goals.

Intel: WiMAX Is Here. Now.

that we need to hide the complexity of the network from the customers in order to make their lives easier.

COMMUNICATE: Taking this into consideration, how does SFR define convergence?

Mr. Allemand: Regarding the customer needs and marketing/commercial issues, SFR views are that customer will demand a simpler access to the benefits of technologies. Therefore, we don’t see convergence as introducing complex and cumbersome products with little perceived benefits. Rather, we think that an operator should work hard in building the ergonomics that will help the customer to understand and use technologies in a safe, simple way: quality of service, ergonomics, customer service and shops, online tools etc. This is why in our merger with Neuf Cegetel, the top priority has been bringing the products under a single brand (SFR) to the market and upgrading continuously the quality and ease of use.

Regarding networks, since the Internet is everywhere, we need to converge fixed and mobile networks (both access and core) in order to allow seamless usage (e.g. Wi-Fi and 3G for PCs) and massive reduction of unit costs in particular of mobile data.

Achieving synergiesThe acquisition of Neuf Cegetel has expanded SFR’s customer base by 3.9 million to a total of 23 million. The biggest value of the combination is the synergy that goes beyond customer gains.

COMMUNICATE: How does the acquisition of Neuf Cegetel contribute to your convergence goals?

Mr. Allemand: The acquisition of Neuf Cegetel by SFR enlarged the business scope to more than 23 million customers in mobile, DSL and fixed telephony, making SFR the second largest global carrier in France and the first largest alternative carrier in Europe. We are able to provide all different offers combining mobile and fixed services. We are now able to answer all the demands of our customers across residential, enterprise and wholesale markets. However, I would not speak about “isolated” networks but more about the great opportunity for SFR to simplify our global network architecture, also from a service provisioning and operating point of view.

Having said that, our challenge is to reorganize our systems to be able to manage and operate more end-to-end

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Our challenge is to reorganize our systemsto be able to manage and operate moreend-to-end services rather than specific mobile or fixed network components.

—Mr. Pierre-Alain Allemand, Senior Executive Vice President of SFR

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services rather than specific mobile or fixed network components. This is one of our expectations vis-à-vis our vendors to support us in that way.

COMMUNICATE: SFR has often mentioned that SFR + Neuf Cegetel is a value creating combination owing to the significant synergies. Could you elaborate on the synergies in the networks?

Mr. Allemand: Top of the commercial synergies, one of the more obvious outcomes from a network view point is definitely the synergy in terms of available core capacity. Based on more than 50,000 kilometers of fibers, SFR benefits already from a full IP backbone originally used for its fixed business and now is also available for mobile business. Our goal is step by step to bring the IP capacity closer to the mobile customer without having to build an additional IP core network. This is the first step of synergy.

We also see synergy opportunities in leveraging on the existing fixed access loops to backhaul the mobile traffic, as well as in the usage of a common Service Platform for mobile and fixed services, like IPTV for example.

Empowering convergenceNetwork capability is the foundation of enabling convergence. How will SFR harness the combined network power to support the convergence?

COMMUNICATE: While the combination brings significant synergies, it would also result in a more complicated network condition. What is the biggest challenge in network management?

Mr. Allemand: I think the main challenge is to be able to come up with the core network connected to different access networks, 2G and 3G networks, DSL, FTTH, Wi-Fi and WiMAX networks in a seamless manner for the customer. The aim from a technological point of view is to offer the same usage experience to the customer whatever the access network he/she uses. This is complex. We are working actively with partners like Huawei and all the vendors in order to reduce the complexity of the technologies in these different networks.

Currently, we are in the phase of the rollout of IMS core. We are deploying IMS application servers, like telephony application server, IP Centrex application server, presence application server. The idea is to be more innovative and reactive in the launch of new services. That’s what we expect from the IMS, to allow us to be more flexible and to speed up the launch of innovative services and also to push the convergence between fixed and mobile access.

COMMUNICATE: What will be SFR’s major

plan for the access networks, in terms of both the fixed and mobile?

Mr. Allemand: On the fixed side, we have set an FTTH objective of 4 million homes passed by 2012 using GPON technology. However, the deployment will depend on the density of the area. We are a bit agnostic to technology. So we use GPON technology but also Ethernet technology. It depends on the situation and the capital investment. So if we take the examples of Paris and suburban of Paris, we will use both technologies depending on the situation and topology of the network.

On the mobile side, SFR was the first French mobile player to have invested in 3G technology, thus proving the group to have recognized leadership. As of the end of 2008, we covered around 99% of the French population with Edge, 3G and 3G+ networks. We still have ambitious plans to enlarge our coverage and maintain our high quality standards. As far 4G is concerned, we are testing different technologies like LTE but it is too early to make a final decision for a massive rollout and commercial launch. So, the first step is to continue to extend the coverage of 3G, and then implement HSPA+, and later we will talk about LTE.

COMMUNICATE: Andy MacLeod, Global Network Director of Vodafone once stated, “As Radio Access Networks are upgraded to reflect growing demand for mobile broadband services, it is important to ensure that the backhaul is able to deliver on that potential.” This explains why mobile operators are investing heavily on backhaul construction, such as Vodafone’s BEP (backhaul evolution program). Could you share with us your mobile backhaul status and future evolution plans?

Mr. Allemand: The current backhaul is microwave mainly and leased line. As I mentioned earlier, SFR has a great opportunity to benefit from its existing fixed access loops (both DSL and FTTH) to backhaul the mobile traffic. That should allow us to minimize our network unit costs while improving our access layer capacity. This should also result in our capacity to support increasing debit requirements for new services. We plan to use a tremendous amount of DSL and full IP in the future. So we need to make mobile access from the legacy technology, like ATM and TDM, to full IP technology.

COMMUNICATE: Neuf has been a pioneer in deploying 40G transport networks supplied by Huawei. What were the reasons for deploying 40G links and when do you expect a real need for 100G links?

Mr. Allemand: It was for the core network to support the growth of the data traffic. As we have

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3.9 million DSL subscribers, data traffic is tremendously increasing on the networks. So, we needed additional huge capacity on our core network. That’s why we decided to upgrade our network in the 10G WDM but also the 40G links in order to sustain the growth of the data traffic.

When will there be a real need for 100G? It is difficult to answer that question. But I would say within 2 or 3 years we will need additional capacity on the core network. The fixed data traffic boomed during the previous years. More increase is seen on the mobile loop as SFR’s mobile data traffic increased by 10 times in 2008. We expect that the next five years will see the data traffic increase between 50 and 100 times. So, we need to ensure that the transport networks are adequate to sustain such huge traffic growth.

COMMUNICATE: Given that more sophisticated convergent services pose higher requirements on the application layer, how would SFR enhance the capability of the application layer?

Mr. Allemand: The major challenge is to design on the top layers a user interface hiding the network diversity including the access layers. The objective is definitely to offer a consistent usage feeling. Subsequently, we need to ensure service continuity whatever the customer uses to access their preferred and customized services, also consistent from a QoS point of view. This is what we call a “Service Oriented Architecture” building up a customer interactive layer over the enabling, middleware and back-office layers. That differentiation allows more flexibility in terms of new services development. We are currently implementing such an approach for the TV services and working on the IMS.

In addition to the network adaptation, convergence also requires transformation of all the IT systems around the network. We are making our IT system able to face the convergence. Today, we have a huge IT optimization program for the billing, the CRM, and all the different layers of our IT system in order to adapt to the network and convergence of new services. The program BIOS started two years ago and will be finished in 2012.

With a 11.5 billion Euros turnover end of 2008, SFR is the second largest French

telecommunications company and Europe’s largest alternative operator supported by

stable shareholders (Vivendi 56% and Vodafone 44%).

By opting to take control of Neuf Cegetel, SFR is now a global operator, with its own

mobile and fixed infrastructures, capable of meeting the needs of its entire customer

base: the mass market of residentials, professionals, businesses and operators. The

launch of the “neufbox” by SFR in early October 2008 is an example of the quality SFR

service strengthening the group’s broadband offer.

At the end of the year 2008, SFR has 19.7 million mobile customers, including 5.9

million 3G/3G+ customers, 3.9 million high-speed Internet customers and 194,000

companies’ sites connected.

For more information, please visit http : //www.sfr.com

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About SFR

Editor: Gao Xianrui [email protected]

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By Sureyya Ciliv, CEO of Turkcell

Moving towards a connected world

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urkcell is the second largest European operator in terms of number of subscribers in a single network. With operations spanning

8 countries and a subscriber base of 61.5 million, it was voted 2008’s 25th best-performing tech company by Business Week which is based on four key criteria: shareholder return, return on equity, total revenue, and revenue growth.

Turkcell is also known for its innovative spirit, which has culminated in several GSMA awards including the ‘Innovations through Human Resources and Skills Programs’ award in 2008 and the ‘Best Mobile Advertising Service’ for its Tone & Win mobile advertising platform in 2009.

In his keynote speech at the Mobile World Congress 2009 in Barcelona, Sureyya Ciliv, Turkcell’s CEO, described how the world is transforming into a connected world, and explained how Turkcell plans to retain its successful market position.

A connected world

Although we live in turbulent times, especially with the global financial crisis affecting us all, I’m still full of optimism about the future. My confidence comes from the areas in which we’re operating. They have, on average, shown more than 7% growth over the last five years. Emerging countries have ups and downs but, overall, they tend to change quickly and grow at a rapid rate. We’re seeing much innovation from emerging markets.

How often do we mention that the world is becoming fat? Think about the history of humanity; this is the era in which we’re

connected to 4 billion people. I was in Davos 3 weeks ago; politicians and experts were discussing health and peace. I realized that our industry – more than any other – is the key to the future of mankind. When we send a signal, it is received by 4 billion people, who respond even from remote parts of Africa, India or China. In less than 4 years, this number will jump from 4 billion to 6 billion: 6 billion people will be connected.

Technology sustains change, and these changes are ushering us into a new world. I describe this world as “a connected world”.

Enriching life

We now connect isolated communities with a very thin wire that provides the basic services of voice and SMS. As this wire thickens, we can facilitate a very rich connection that can realize high level services such as real-time video streaming. The future is driven by three factors: mobility, Internet, and convergence. Mobility continues to gain in momentum due to society’s increasing demand for mobility. The Internet has unequivocally changed our lives and continues to do so on both fixed and mobile lines. Convergence is transforming our phones into mini-computers, mini- televisions, mini-independent devices, mini-education devices, and mini-game devices. They can incorporate software and applications, which are occasionally richer than those found on PCs. Please do a test when you go home; Google “Pizza”, and see what you get. I estimate that you’ll get around 288 million answers. What you are really looking for is the closest Pizza store in Barcelona.

I will demonstrate it by introducing some applications that we’re successfully using in

Turkcell. Firstly, our signature product in mobile marketing, Tone & Win, won the top award in the ‘Best Mobile Advertising Service’ category at the 2009 GSMA Mobile World Congress. This mobile advertising platform is the world’s first RBT advertising platform and has grown rapidly to reach its current total of 200,000 users. Using Tone & Win, Turkcell customers can select branded content instead of a regular RBT. They can earn airtime or credits depending on the amount of time callers spend listening to their RBT advertisement music. Tone & Win represents a world leading program that allows commercial companies to sponsor calls for those who’re willing to accept the advertisement.

Secondly, we have Mobile Signature, in which we’re using the phone as an intelligent authentication device. In Turkey, if you go to a bank, you no longer need a bank card; you can use your Turkcell mobile signature as a unique identification tool to complete your transaction. So, now when you leave home, it’s okay to forget your wallet, but not your cell phone! By working jointly with banks and finance companies, we’re able to conduct many banking transactions on-line and through cell phones.

Thirdly, we offer the health program, called Mobile Healthcare. There are about 40,000 villages in Turkey, but we lack 40,000 specialists in every branch of medicine to allocate to each village. Therefore, we’ve deployed mobile communications to connect patients in these villages to specialists in central Turkey.

We also provide a range of other innovative services: Jointly developed with Mobile Signature, Mobile Key is a system that helps you open the door of your house for your visitors, even if you are abroad; Our

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mobile traffic program, IBB Traffic, saves time by highlighting where the motorways are congested or smooth-flowing. Mobile Education allows users to maximize the use of their time to learn about our new technologies without having to visit one of our branches.

These are some examples of what the mobile world can do for us. It can even solve some problems that have never been solved before, and also ease and enrich our lives.

Te be or not to be?

Now you may say that it is nice but it is not happening. It is not happening fast enough and that we’re not changing fast enough. Are operators going to be a simple pipe, or are they going to be service providers?

Two years ago, we decided that we didn’t

want to be defined as a GSM voice operator. We expanded our business parameters to become a complete telecom company. As an operator, we feel very excited about the future; technology is always changing, which creates new opportunities. Software technologies and hardware technologies will become key facets of our future.

It’s challenging to provide a set of services on top of the basic pipe infrastructures that we have been traditionally operating. There are numerous companies from a range of industries that feel they are here to replace or compete with us, and there are many that we didn’t think were part of the telecom industry 5 years ago; now they are trying to change the industry and become key players. Like many companies with a background in software, they understand information services better than telecom operators.

However, telecom operators also have something unique: the relationships that are

based on years of reliable services and trust. Today, Turkcell enjoys relationships with 61.5 million people in 8 countries. They trust us, because communication is a very important part of their lives that we continue to deliver. So, how can we build on this asset to create innovation? That is the challenge for operators.

Key to successHow will mobile operators seize

opportunities? From my technological perspective and world experience, I really believe there are two key issues that we need to resolve.

First is value. The consumers that we serve need to see and experience value. More importantly they need to recognize that it is value. Our job is to ensure that they understand the benefits and that costs are controlled. If one is receiving messages when traveling to other European countries from Turkey. But he is charged ten Euros for one megabyte. How can operators promote mobile Internet if one megabyte is ten Euros! So, price is part of the value equation and we need to exercise caution.

The second issue is user experience. If an application is not simple enough, it will never become mainstream. Simplicity in terms of user experience is the biggest challenge we are facing. The industry is moving from voice-centric to Internet-centric. We’re incorporating the applications that I introduced to you previously into Turkcell’s service package. Today, we have Microsoft, Nokia, and other media companies that also feel this is great opportunity. Whether we can translate it into a simple user experience, though, is the most pressing and complex challenge. The players and the eco-system need to be aligned, and at times it is tough to align corporate giants. Many companies are becoming very self-centered and only think “how can I benefit from the boom times?”

I believe it’s time to create partnerships. It’s time to create a seamless, simple user interface; personalized interactive services will help users simplify their lives and view information without location and time restrictions. If high-value applications are simple, they can supply outstanding user experiences; then we will see technologies very quickly become mainstream.

Two years ago, we decided that we didn’t want to be defined as a GSM voice operator. We expanded our business parameters to become a complete telecom company.

Editor: Gao Xianrui [email protected]

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—Mr. Sureyya Ciliv, Turkcell’s CEO

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Strategy: services drive transformationFull service era

h e t h r e e l e a d i n g C h i n e s e o p e r a t o r s a r e c u r r e n t l y establishing their full service operation strategies following

the issue of 3G licenses. The prevalent market environment has clarified the positioning of mobile communications, the Internet, media, and ICT convergence. Fu l l s e r v i ce opera to r s a re sh i f t ing to converged IP multimedia service provisioning, while prioritizing customer demands and segmenting markets to reduce subscriber churn.

China Mobile Zhejiang mapped out

New power with the new PTN

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By Lv Lingling

its full service development plan in May 2008 based on an open and forward-looking strategy, with a focus on TD-SCDMA and fixed broadband services. A key component of the company’s marketing strategy centers on launching combined “private line, ICT, fixed and mobile services” for large enterprises and integrated “broadband, fixed line, and mobile services” for home users. China Mobile Zhejiang is driven to create FMC-based networks and Internet data centers (IDCs) that deliver a superior experience for subscribers through high-bandwidth services, including ubiquitous TV.

China Mobile Zhejiang has established its comprehensive network development plan for the next five years, and predictions hold that the company’s mobile data subscribers will increase to 2 million by

2014, while its fixed broadband market share wil l reach 35%. In Hangzhou (the capital city of Zhejiang province) alone, the company is expected to extend its existing 4,000 base stations up to 50,000 points of presence (POP) over the next five years. As the basis of network infrastructure, China Mobile Zhejiang’s bearer network must become packet-based.

Transforming to packet transport

Bandwidth, time delay, and QoS are the key factors that could greatly affect network quality, and providing sufficient bandwidth has proven to be the greatest challenge to date. Preliminary estimates reveal that an ordinary S3/3/3 TD-SCDMA Node B consumes 2 × 2M bandwidth and 4×2M–8×2M when

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China Mobile’s PTN construction in ZhejiangAs a pioneer in full service operation and 3G network construction, China Mobile Zhejiang’s mission to raise its market equity is coming into focus after selecting the optimum technology for its bearer network. To date, the operator has made solid progress with its packet-based bearer network; having established the world’s largest PTN to Node B access, the company has laid a solid foundation for 3G network deployment, full service operations, and the smooth evolution to LTE bearer networking.

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deployed over HSPA. Even so, this solution only addresses TD-SCDMA Node B requirements.

China Mobile Zhejiang has planned numerous integrated information access points, one of which consumes at least 10Mbps for an enterprise customer, while a single Node B must provide a minimum of 20 broadband access points for homes. Assuming that 20 homes combine at one access point, each currently requires 2Mbps, which will subsequently rise to 20Mbps. The subscriber concentration ratio is 1:4, meaning that one access point must provide up to 200Mbps bandwidth for home users. China Mobile Zhejiang’s legacy TDM-based SDH network falls far behind this bandwidth requirement.

Furthermore, the wireless network evolution roadmap has painted a clear

picture for operators to choose the right bearer network technology. So far, the TD-SCDMA Node B can upgrade to support LTE. Over the next two years , TD-SCDMA networks will seamlessly evolve to LTE TDD, and benefit from LTE’s broadband capability of up to 50Mbps. In this sense, the bearer network should provide each Node B with a 50–100Mbps access capability.

According to bandwidth requirement analysis, China Mobile Zhejiang decided to shift to packet bearer technology to overcome the bandwidth issue.

Technology: PTN stands outHigh requirements

The carrier Ethernet, provider backbone

transport (PBT), packet transport network (PTN), router/MPLS, and xPON are examples of technologies that may serve transport needs. However, consultants, equipment providers, and industry experts are divided on their respective merits despite having evaluated various fixed and mobile operators and analyzing possible options and their outcomes.

S ince June 2008 , China Mobi l e Zhejiang has held talks with several equipment providers concerning the selection of the optimum bearer network technology. The operator finalized the basic requirements for its new-generation packet bearer network after comprehensive research and assessing test results, existing network characteristics, and the availability of maintenance staff.

E 2 E c a r r i e r - c l a s s n e t w o rk i n g :

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New power with the new PTN

Currently, packet bearer technology is mostly employed in China Mobile Zhejiang’s TD-SCDMA Node Bs. IP RAN requires the same end to end (E2E) scheduling, networking capabilities, r e l i a b i l i t y, a n d h i g h Q o S a s 2 G networking. The packet bearer should not degrade bearer network quality, and so must deliver high reliability, QoS, and E2E networking capabilities.

Easy management and maintenance: A t the in i t i a l s t age o f fu l l s e r v i c e operat ions, China Mobile Zhej iang lacks sufficient data and IP technology technical staff. Industry statistics suggest that while each maintenance employee can maintain over 300 sets of transmission equipment by utilizing a powerful network management system (NMS), each can only handle a few dozen sets of data equipment, with particular limits on routers. If packet technology is introduced on the network bearer layer, China Mobile Zhejiang would have to maintain thousands of sets of packet equipment operating on local networks. Given that the company’s current maintenance staff are unable to realize the necessary maintenance requirements, packet bearer equipment should preferably be able to provide a management capability similar to SDH equipment.

Rigid clock synchronization: TD-

SCDMA networking requires 0.05ppm frequency synchronization and 3us phase synchronization, while LTE has even higher requirements. Node Bs presently rely on GPS for synchronization and replacing the GPS necessitates synchronous support from a land-based bearer network to achieve a balance between construction, cost, and network security. To date, only the IEEE 1588v2 protocol supports both frequency and time synchronization. To allow China Mobile Zhejiang to evolve its TD-SCDMA network, packet bearer network equipment must also support this protocol.

High-QoS statistical multiplexing: China Mobile Zhejiang’s value-added broadband services are booming; mature 3G technology and LTE will call for even higher bandwidth per Node B due to the surge of broadband services. Statistical multiplexing above the convergence layer saves considerable bandwidth, but will inevitably intensify competition for channels. Traffic classification alone cannot deliver QoS requirements for different service levels; therefore, the bearer network demands hierarchical QoS and an effective scheduling mechanism to accommodate China Mobile Zhejiang’s needs for TD-SCDMA and LTE service segmentation.

Unified service bearing: China Mobile Zhejiang’s TD/LTE and GSM networks

will co-exist over the long term. This fuels the need to combine TDM, ATM, and IP bearer capabilities; the packet bearer network must provide a unified service bearing capability.

PTN for the long term

In l ight of these analyses , China Mobile Zhejiang believes that traditional Layer-2 statistical multiplexing helps enhance bandwidth utilization, but fails to guarantee QoS, network management, and service scheduling.

However, PTN is the silver bullet: Firstly, it inherits SDH’s carrier-class performance, as well as the statistical multiplexing and multicast capabilities of Layer-2 equipment; it also incorporates a packet network core to meet the high bandwidth requirements of TD-SCDMA and the fu tu re LTE Node Bs , and provides a hierarchical QoS mechanism capable of supporting the operator’s future differentiated operations. Secondly, PTN incorporates SDH’s protection, monitoring, management, and E2E service configuration advantages. Packet t e chno logy enab l e s Ch ina Mob i l e Zhejiang to deliver network bearer quality comparable to SDH, which fully meets the company’s TD-SCDMA Node B transport requirements.

The resulting consensus agreed that the Huawei PTN solution offers superior performance and O&M, and verified the solution’s capability to support commercial deployment on a massive scale. Moreover, the PTN matches IP RAN bearer requirements and optimally bears services through Node Bs.

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PTN accommodates different wireless networks’ timing information through synchronous Ethernet and IEEE 1588v2 technologies for clock transmission. By, for example, supporting GSM, TD-SCDMA, and LTE networks, PTN can meet China Mobile Zhejiang’s requirements for GPS transformation on its current TD-SCDMA Node Bs.

Facts shout the loudest

China Mobile Zhejiang set up a PTN pilot in Ningbo with Huawei’s help in October 2008 to verify the technology’s advantages. Simulating various service bearer scenarios through 50 test cases, the one-week trial was successful on all counts. Moreover, China Mobile Zhejiang adopted statistical multiplexing, and examined PTN’s LSP configuration, E2E OAM, and each service’s QoS.

Notably, Huawei’s PTN solut ion integrates a graphical NMS that inherits China Mobile Zhejiang’s existing SDH maintenance interfaces and routines to ease the maintenance burden. Over 30 emp loyee s f rom Ch ina Mob i l e Zhej iang’s provincial and city- level branches participated in the trial and final acceptance test. The resulting consensus agreed that the Huawei PTN solution offers superior performance and O&M,

and verified the solution’s capability to support commercial deployment on a massive scale. Mr. Wang, the chief engineer at the provincial center, commented that the PTN matches IP RAN bearer requirements and optimally bears services through Node Bs.

Implementation: success lies in professionalismAct as planned

Shortly after determining which bearer technology to employ, China Mobile Zhejiang began its drive to establish the PTN implementation plan. Despite the wide application of PTN equipment over mobile bearer networks abroad, China Mobile Zhejiang’s PTN vision represents the first project of its kind in China, and is notable for its massive scale and complex applications.

The inevitable changes in bearer traffic over the next two or three years require that the solution adapts to shifts in network size, equipment models, and business plans. Given the challenges that the project will undoubtedly incur, the company’s design, planning and network divisions exercised caution during the implementa t ion p lanning proce s s .

Moreover, China Mobile Zhejiang studied various international PTN applications to enrich its own experience and help stimulate the success of the project.

Huawei has contributed significantly to worldwide PTN development, with the vendor’s solutions having been applied in 20 countries by globally leading operators. Huawei’s rich experience has positioned it as a vital strategic partner for China Mobile Zhejiang and Huaxin Consulting, the network planning consultant for this project.

Du r i n g t h e i n i t i a l s t a g e s , t h e operator and consultant both required a comprehensive knowledge base of PTN standards and key technologies. Huawei responded with a personalized training program in Hangzhou oriented to their needs. One-week of training gave technical staff a full understanding of PTN and its advantages in terms of Node Bs and private line service bearing, and also fortified the operator’s confidence in PTN, thus increasing momentum for project implementation.

Huawei’s senior PTN R&D engineers were sent to Hangzhou to explore China Mobile Zhejiang’s network status and future development with engineers from the operator and Huaxin Consulting. Various research activities by Huawei culminated in a complete set of business plan templates to construct a high-quality

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PTN, spanning equipment selection, network capacity, service planning, and statistical multiplexing.

The state-of-the-art solution• Equipment selection and network

capacity

China Mobi le Zhe j iang se l ec ted Huawei’s PTN 3900/1900 to construct an E2E packet bearer network and evolve its transport network towards All-IP. This decision was based on the equipment’s outstanding performance in a pilot scheme in Ningbo city and its proven quality following commercial deployment in various locations across the globe. The project was launched for China Mobile Zhejiang’s Hangzhou branch with 1,900 sets of PTN equipment deployed across the Hangzhou network to support future business expansion.

Hangzhou is noted for its pleasant natural environment and attractive scenery, which the city’s cit izens are keen to preserve by reducing energy consumption and CO2 emissions. To save equipment room space and auxiliary resources, the operator’s Hangzhou branch has deployed large numbers of co-located 2G/3G base stations. Thus, the PTN bearer network has to meet the co-location needs and equally address the bearer requirements of optical line terminal (OLT) uplink and the wireless local area network (WLAN).

More than 400 new sites are in place to s imultaneously transmit 2G and 3G services across the city. To achieve this, Huawei recommended that the Hangzhou branch flatten its network into access and convergence layers ; OTN will be deployed on the backbone layer to perform scheduling, while PTN equipment positioned in the BSC and RNC equipment rooms can be used to terminate and upload services. In addition to providing service bearer capability for the Hangzhou branch’s 3G Node Bs, the solution delivers unified access for subsequently added GSM base stations to help minimize CAPEX and OPEX.

• Service planning and configuration

The TD-based service model provides point-to-point connectivity. However,

in IP RAN applications, the interfaces be tween the RNC and Node B a re increasingly based on IP and Ethernet, for which transport network planning and design differs, especially for IP addresses and VLAN planning. The Hangzhou branch requires an easy to maintain, simply configured network to eliminate unnecessary O&M tasks. In response, Huawei suggested assigning a separate VLAN for every Node B since the VLAN ID mechanism can effectively locate faults and schedule services.

• Statistical multiplexing and QoS settings

As 3G ne tworks de l i ve r a b road range of services that vary in values and requirements, the Hangzhou branch decided to classify TD-SCDMA services on an initial 3G network.

Voice services consume low bandwidth but demand strict QoS, low time delay, low jitter, and minimal packet loss. As a result, bandwidth must be calculated and preserved for voice services and prioritized on Node B and the RNC. Traffic is policed at the network egress and higher priority services are processed first in the transport network. Conversely, data services on Node B and the RNC are lower in priority, consume higher bandwidth, and require lower QoS.

Statistical multiplexing may cause future bandwidth shortages given that TD-SCDMA services are expected to

double over the next two to three years, leading the Hangzhou branch consider the challenge of upgrading and adjusting its network. If statistical multiplexing is performed after bandwidth increases, the operator needs only to adjust the concentration ratio at the convergence layer. At that time, the company will have more accurate service traffic statistics for different regions and times, from which to develop a feasible concentration ratio.

A mature service classification mechanism and a scientific reference point for setting PTN QoS will be in place when the operator enters mature 3G service operations. This in turn has prompted the Hangzhou branch to adopt LSP E2E transparent transmission for its PTN.

Huawei has customized a remarkably simplified QoS template for the company’s TD-SCDMA services to configure LSP, schedule the backbone network, and grade QoS. This template can also act as a blueprint for other cities through just a few simple data revisions, which will greatly expedite and ease network-wide PTN implementation on a massive scale.

To date, China Mobile Zhejiang’s PTN planning and construction has progressed rapidly, and should be completed in 2Q 2009. As the world’s largest packet transport network at the Node B level, the PTN has laid a solid foundation for 3G network deployment and can be smoothly evolved to an LTE bearer network. The PTN will provide carrier-class IP bearer

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New power with the new PTN

As the world’s largest packet transport network at the Node B level, China Mobile Zhejiang’s PTN has laid a solid foundation for 3G network deployment and can be smoothly evolved to an LTE bearer network.

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Huawei Communicate

network (PON) is more cost-effective as its broadband access points are mostly individual users. Therefore, the PTN solution suits unified bearer applications at access points above Node Bs or in suburban areas with small broadband traffic levels. In urban areas with densely traffic, the “PON + PTN over OTN” solution serves bearer needs as OTN and WDM capabilities extend their reach to the convergence and access layers.

Underpinning the solution, China Mobile Zhejiang and Huawei reached a consensus on bearer network technologies and equipment development trends: PTN or OTN supporting PON; upgrading SDH to support PTN; and a unified NMS to allow the bearer network to schedule and monitor E2E services.

As full service operation deepens, the two companies will intensify cooperation to select a bearer network construction and technological platform that accommodates IP requirements. Huawei is committed to helping China Mobile Zhejiang transform from a mobile information expert to an integrated information service provider. Li Weishi, President of the Huawei Metro Ethernet Product Line, states, “Huawei is honored to help China Mobile Zhejiang construct China’s first All-IP based transport network at the Node B level. The project exemplifies commercial TD-SCDMA deployment and has accelerated China’s 3G network deployment and development.”

and transport capabilities. Zhong Tianhua, China Mobile Zhejiang’s General Manager, offered high praise for the Huawei solution, commenting, “China Mobile Zhejiang has maintained a sound partnership with Huawei. We hope that Huawei will help us achieve success in TD-SCDMA network construction on the strength of its rich global market experience.”

Outlook: convergence sets the tone

According to marketing experts, value- added services (VASs) are becoming high definition, fully interactive, and intelligent applications. Content-led consumer communication products will increase demand for converged services and usher the communications industry into a service-centric era.

China Mobile Zhejiang’s full service operation plan requires a shift from simple service bundling to seamless service integration, under which FMC networking forms a key part and the bearer network adopts unified bearing capabilities.

The dramatic growth of bandwidth-hungry data services is increasingly consuming network resources , and expandability is outpaced by demand. The backbone network must be further flattened to reduce network construction costs and improve service bearer quality. China Mobile Zhejiang believes that an Editor: Li Xuefeng [email protected]

OTN on the backbone layer will unify the network and introduce IP and optical capabilities. The OTN supports optical/electric switching, which greatly increases networking flexibility and provides potential for a full-mesh backbone network.

Directly connected converged nodes reduce traffic and lower equipment costs by over 40%. Moreover, the network’s forwarding efficiency, scalability, and maintainability are greatly enhanced. The OTN solution’s optical/electric switch and IP network L3 routing combine to augment networking reliability and meet China Mobile Zhejiang’s future requirements for bearing unified services and seamlessly scheduling services.

China Mobile Zhejiang favors a multi-service control gateway (MSCG) on the MAN control layer to cover different control points for various services given that it optimizes adaptation to FMC. The converged network incorporates broadband remote access server (BRAS), service router, provider edge (PE) router, and xGSN capabilities, which enables smooth network evolution and investment protection.

Due to varied access applications and complex i ty, the coex i s tence of multiple complementary technologies is inevitable. China Mobile Zhejiang ha s e xp lo red th e PTN’s t e chn i c a l adaptability and economies of scale and found the solution to be distinguished by i ts s trong, hierarchical QoS and reliability. Additionally, the passive optical

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PTN17

Openness and cooperation drive WiMAX development

ushers in the future of IP service transport By Bill Huang & Li Han

PTN ushers in the future of IP service transport

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he mobile Internet will become a major component of the next generation Internet. Next generation mobile broadband

networks have to satisfy traditional telecom and mobile Internet services together. IP transformation of services and packet transport will become the mainstream trends in future network evolution.

On the access layer, the next generation m o b i l e a c c e s s n e t w o rk e vo l v e s t o LTE, and PON will gain popularity as the mainstream technology for fixed broadband access. On the trunk layer,

The PTN conceptIP transformation and carrier-class

reliability are the two driving forces for the evolution of MAN. The IP transformation of services refers to the encapsulation of voice, data and multimedia services into IP packets identified by IP addresses. Network IP transformation indicates that IP service bearing is the primary work for both mobile and fixed networks.

The diversified and bursting IP services require bearer networks to ensure the quality of service (QoS) and statistical multiplexing. Pure Layer-1 solid pipe technologies represented by SDH gradually phases out in the bearing of future IP services. Traditional MAN services are typically convergent; the switching and routing of MAN services are generally implemented on the core or convergence layer. P2P services and LTE X2 interfaces require full mesh networking which demands increasingly higher flexibility.

The IP transformation of services does not require all services to be transmitted in the best-effort delivery mode. Scalability, reliability, manageability, and service quality remain the basic requirements for a MAN. For instance, the LTE requires that the unidirectional delay of an S1 interface should not exceed 5ms, the TD-SCDMA system demands the precision of time synchronization to be better than ±1.5us, and 50ms switchover capability is still considered an important indicator of network reliability. Connectionless-oriented Ethernet and IP technologies face challenges in QoS, protection, and management.

In recent years , the carr ier -c la s s Ethernet (CE) and the PTN have become a key focus. The CE focuses on the five major characteristics of carrier-class services, whereas the PTN focuses on the packet transmission of transport networks.

The mainstream PTN technologies are MPLS, MPLS-TP and PBB-TE. Their core concepts involve utilizing the encapsulation and forwarding mechanisms of MPLS and Ethernet respectively. The original packet switching and QoS mechanism are retained and certain complex Layer 3 or Layer 2 protocols a r e r e m ov e d . T h e c o n n e c t i o n l e s s

T IP over WDM/OTN networking i s dominant and can meet the requirements of long-term service development. On the Metropolitan Area Network (MAN) layer, the SDH/MSTP, Ethernet, and IP/MPLS technologies are all competing for a market share, but they show different limitations in broadband convergence and backhaul applications. In this context, the packet transport network (PTN) technology that combines guaranteed performance of transport and dynamic performance of packet will certainly usher in the future of IP service transport.

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New opportunities for wireless broadbandIMS: the time is now中国电信为CDMA产业注入活力

Bill Huang is President of the China Mobile Research Institute and has long been an advocate of new technologies, with more than 23 years of experience in the telecommunications industry. He possesses a wealth of experience and striking insights in the areas of next generation mobile switching systems, IP streaming media, G/EPON systems, multi-service softswitches and Operation Support Systems, as well as mobile Internet and terminals.

Main Topic

characteristics of the Ethernet are eliminated such as MAC address learning, spinning trees, and flooding. The OAM capability is reinforced to implement hierarchical service and network management and also to protect the network. Moreover, to improve network flexibility, a control plane is introduced to the PTN to discover resources and automatically set up connections. A powerful management plane is also available to control and manage the dynamic characteristics.

The PTN combines guaranteed per formance of transport and dynamic performance of packet, implements connection-oriented IP transformation and carrier-class services, reduces network complexity and decreases costs by removing as many complex protocols and processes as possible. This designing principle of PTN has many advantages in MANs.

First, the convergence layer and access layer of existing MANs are mainly converged services that do not require strong routing functions. The PTN statistical multiplexing and QoS capability can ensure the IP transformation of services.

Second, a MAN covers a wide area and involves many nodes. The connection and protection through network management systems (NMSs) can better handle low delay, low jitter, and rapid protection switchover.

Third, in a similar way to the hierarchical OAM mechanism of an SDH network, the PTN facilitates fault location and enhances network O&M.

Fourth, the PTN constructs a symmetrical network by adopting two-way LSP technology to facilitate time synchronization through the IEEE 1588v2 protocol.

Fifth, a control plane can be introduced on the PTN to enhance network flexibility and meet the demands for bearing future services.

At present, the MPLS-TP standards jointly developed by the IETF and the ITU-T are popular among telecom operators and vendors. MPLS-TP is gradually becoming the mainstream PTN technology.

Key technologies

Hierarchical multi-service transport network model

MPLS-TP implements the logical hierarchy of service paths, transmission channels, and physical links by adopting a hierarchical network mode that involves the pseudo wire (PW), the LSP tunnel, and the MPLS section. By dividing logical functions inside a transport network, network and service topologies become distinct. This delivers convenient and effective network O&M, easy fault isolation and alarm control, largely reducing the number of connections maintained by the transport network.

The PW laye r i s re spons ib l e fo r the un i f i ed encapsulation of services and provides end-to-end (E2E) transparent transmission paths to transmit multiple services. The IP/MPLS technologies have already developed a complete set of service encapsulation modes. The PTN adopts the PWE3 protocol defined by the IETF to realize packet-based encapsulation for the multiple services of the Ethernet, TDM, and IP. This way the PTN ensures relative independence of the transport network from the service network, bringing a clearer maintenance interface for the two networks. This effectively solves the isolation problem that occurs when the IP and MAC packet headers are used as labels in the transport network.

The PTN combines guaranteed performance of transport and dynamic performance of packet, implements IP transformation and carrier-class services, reduces network complexity and decreases costs. This designing principle of PTN has many advantages in MANs.

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plus protecting the QoS characteristics of delay, jitter, bandwidth and the packet loss ratio of services against the impact of device forwarding performance.

Switches and low-end routers are generally designed with shared memory or shared bus architecture with an integrated storage forwarding mechanism that has performance bottlenecks. The bus contention or time restriction of memory access leads to long delays, high jitter (normally at the millisecond level) and occasionally packet loss. As a result, the QoS precedence cannot be ensured.

Complete QoS mechanism ensured by connection-oriented networking

E2E QoS requires connection-oriented networking. In a dedicated IP bearer network for services with high QoS requirements, IP routers are designed with connection-oriented MPLS TE technologies to ensure the QoS of IP services by integrated path planning and bandwidth reservation. This lessens the impact on QoS by disordered flows caused by dynamic routes.

MPLS-TP inherits the connection-oriented feature of MPLS TE and sets up MPLS tunnels through centralized NS or the control plane. In addition, the MPLS tunnels set up by MPLS-TP are static transport tunnels that do not need refreshing by dynamic routes. The static tunnels are affected only by changes in the link status and service configuration, eliminating the impact of fault proliferation and route flapping caused by refreshing dynamic routes.

The PTN supports services in dual directions through bi-directional LSP. Dual direction services ensure the consistency in delay and transmission paths and halve the number of connections.

New opportunities for wireless broadbandIMS: the time is now中国电信为CDMA产业注入活力

Li Han has extensive experience in optical communications, access and home networking technology research. He is currently working on transmission and IP for the Network Technology Research Subdivision of China Mobile Research Institute. As an editor of ITU-T, Dr. Li has published more than 30 ITU manuscripts and over 50 papers at home and abroad, and applied for over 20 patents.

The LSP tunnel layer contains the PW service paths of multiple identical routes. In the transport network, the LSP tunnel layer shields the restriction of the physical link layer and realizes bandwidth allocation, flexible scheduling, and E2E fault isolation. MPLS-TP adopts proven MPLS tunnel technology applied in the MPLS VPN networks to determine traffic flow and volume, forming an E2E transport tunnel.

The MPLS section corresponds to lower-layer physical links such as an independent optical fiber cable or wavelength. The MPLS section monitors link status and performance to serve for error-free transmission of the upper layer network.Non-blocked packet switching system architecture

To ensure high QoS requirements for dedicated line and voice services, the next generation PTN devices are designed with non-blocked packet switching system architecture. The QoS of a packet network should be first guaranteed by the system architecture of the device. The switching architecture of PTN devices can be classified into two types: non-blocking crossbar cell switching architecture, and low-cost shared bus or memory architecture.

The non-blocking crossbar architecture is represented by high-end routers and ATM switches. The forwarding module of these devices slices each forwarded packet to fixed-length cells and then restores them as complete packets after the non-blocking cell switching at the switching module. Fixed-length cell switching eliminates the delay inconsistency of handling cells of different lengths, thus ensuring the forwarding of each port at the line rate, implementing strict service precedence policy,

At present, the MPLS-TP standards jointly developed by the IETF and the ITU-T are popular among telecom operators and vendors. MPLS-TP is gradually becoming the mainstream PTN technology.

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High performance E2E OAM realized via hardware

The most prominent edge of the PTN lies in the high performance hierarchical OAM mechanism that accurately locates faults in real time in a complex network topology. This addresses the defects of IP/MPLS networks in fault detection, fault location, and alarm control.

MPLS-TP def ines a h ie rarch ica l OAM packet handling mechanism for the three layers of PW, LSP tunnels, and MPLS section. By supporting a hierarchical network, the upper layer OAM information can automatically be inserted in sequence into the lower layer link, providing a protocol basis for status transmission and alarm control.

MPLS-TP defines complete OAM packets, including CC&CV used for connectivity detection. AIS packets are used to suppress downstream and secondary alarms. RDI packets are used to reversely insert remote alarm indicators and maintain link status in dual directions and LB packets as a means of network maintenance.

Troubleshooting traditional routers is done with software and performance is restr icted by the CPU processing capability. The number of LSP protection groups supported by a high-end router generally does not exceed 2,000. The router cannot handle the tens of thousands of service protection groups required in an MAN. The OAM packets of the PTN are processed by the hardware which greatly improves performance.

Thanks to the complete OAM fault detection and transmission mechanism, the PTN can detect a fault within 10ms to meet the 50ms switchover requirement. MPLS-TP/T-MPLS defines explicit linear and ring protection functions and supports multiple network protection technologies including 1+1, 1:1, and ring protection to accommodate a variety of network topologies.

E2E integrated NMSThe avai labi l i ty of an NMS is an

important indicator to evaluate the commercial deployment of PTN devices. The integrated PTN NMS provides E2E

service configuration, fault location, performance monitoring, and routine maintenance.

The integrated E2E NMS is built up on the basis of connection-oriented networking models and E2E OAM. The connection-oriented networking model maintains a distinct E2E topology of services and networks, enabling the planning and deployment of service flows. High-performance OAM monitors the status of a link node in real time and the hierarchical OAM effectively suppresses secondary alarms so that attention can be focused on root alarms. In addition to the integrated static NMS configuration, PTN service can also be automatically set up by the control plane using the flexibility of proven IP routing protocols.

Market prospect

For operators, the development of 3G and full service operations has meant urgent demand for IP transport solutions on MANs. The concept of using PTN to combine guaranteed performance of transport and dynamic performance of packet is now recognized by many operators and equipment manufacturers and it is expected to become mainstream MAN technology.

As indicated in current tests and pilot projects, most PTN devices are capable of bearing multiple services and meet performance indexes covering delay, jitter, error bits, and packet loss. The 1:1 protection satisfies the 50ms switchover requ i rement . The dev i c e s o f some manufacturers support IEEE 1588v2 with the precision of synchronization signals on ground transmission better than ±1us.

MPLS-TP OAM standards are still incomplete and the T-MPLS OAM mechanism is mostly applied. For network maintenance and management, E2E service configuration and management need to be strengthened. Operators also need to accumulate experience to set QoS parameters.

PTN will be first applied to MANs thanks to its maturing technologies, standards and industrial chain.

Editor: Xue Hua [email protected]

As indicated in current tests and pilot projects, most PTN devices are capable of bearing multiple services and meet performance indexes covering delay, jitter, error bits, and packet loss.

PTN ushers in the future of IP service transport

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Find the right pitchAnalysis on different mobile bearer network strategies

What makes an optimal mobile bearer network?

he mobile subscriber base and wireless coverage are expanding exponent ia l ly and mobi l e bearer networks are getting

an increasing percentage of operator investments. Notably, as mobile data services boom, the bearer network is of growing importance for mobile operations and becoming a core component for remaining competitive.

A mobile bearer network comprises the network media and devices that are used to transfer user data and control signals between mobile systems. The network uses physical media, such as optical fibers, microwave devices, copper cables, and leased lines, as well as various devices, such as optical transmission devices, switches, routers, and access elements. Employing a range of technologies, including SDH, ATM, MPLS, TDM, and G.SHDSL, it covers the backbone, convergence, backhaul and access layers.

Among the current bearer platforms, the mobile bearer network involves the

T

What are the values of a mobile bearer network? How can we create an optimal mobile bearer network to realize the values?

By Bian Mingang

most product fields, with the most flexible technological choices and the most complex networking modes.

How to make the best choice for a mobile bearer network? Over the past few years, this has been a hot topic. How do we respond to the high bandwidth driven by HSPA? Undoubtedly ATM will be obsolete but is it time to phase out SDH also? What kind of packet bearer platform is needed to support All-IP? Should routers be deployed at network edges? How do we balance L2 network cost efficiency and L3 service flexibility? How do we proportion self-constructed networks to leased lines? How do we realize FMC? How do we reflect the value of the bearer network in mobile operations?

Operators are facing a wave of problems and challenges that span various aspects, technologies , equipment types and networking modes. Closer inspection reveals that for mobile operators, realizing the values of the bearer network and developing the optimal network solution portfolio among various technologies and devices are of prime importance. We can approach the issues by identifying different factors that affect the mobile bearer network.

Factors affecting the mobile bearer network

Multi-system compatibility

The job of a mobile bearer network is to transfer user data and control signals between mobile systems. Obviously the mobile system structure requirements determine the functions of the mobile bearer network.

I n t e r n a t i o n a l s t a n d a r d i z a t i o n organizations have established numerous global standards for mobile network systems in the 2G era. Due to differences i n t h e e c o n o m i c a l e n v i r o n m e n t , sh a reho ld ing s t r u c tu re s , bu s in e s s objectives, and regulatory policies, mobile networks vary worldwide. To compound the problem, one transnational operator even needs to adopt different mobile network systems in different countries.

In addition to responding to differences between countries and regions, operators have to deliver networking capacities across mobile systems to accommodate requirements of different subscribers, services and revenue modes.

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Find the right pitch

For example, operators may need to construct a UMTS network to cover urban areas in addition to nationwide GSM coverage. They may still need to extend WiMAX network coverage to airports and libraries or even try out LTE in these areas while providing HSPA coverage in business districts and upscale residential areas. In bearer network construction, mobile operators must cope with the utilization and long-term coexistence of multiple network systems.

However, compatibility with multiple network systems alone cannot support the value proposition of mobile operators toward the bearer network.

Support for different operational strategies

Even in the same region, different operators run dif ferent operat ional strategies that directly affect mobile bearer network requirements. In France, for example, Vodafone and Orange differ greatly in operational strategies despite their consistent strategy to develop broadband services.

The local leading integrated operator,

access bandwidth between 2–3Mbps for HSPA-based mobi le broadband services. Technically, the bandwidth seems incomparable to Orange’s 10Mbps bandwidth over copper wires or fibers, but the 2–3Mbps mobile bandwidth serves the needs of most subscribers even without IPTV capabilities. Therefore, Vodafone prioritizes network mobility.

Clearly, due to different operational strategies, operators differ largely in their need for mobile bearer networks, which in turn, directly influences their network construction modes.

Knowledge and analysis of mobile operational strategies represent the first step toward understanding and realizing the values of a bearer network. This raises more questions. Will mobile operators focus on 2G network coverage or fast HSPA deployment? Will they sharpen their core competitive edge by introducing LTE or merging with a fixed network operator within the year? These should be answered before relevant bearer network solutions are defined.

Status quo of different bearer networks

Orange possesses the largest mobile and broadband subscriber base as well as the most extensive pool of mobile and broadband network resources. Therefore, Orange prefers to draw more subscribers through FMC services . In terms of broadband service, the company favors increasing the bandwidth for broadband app l i ca t ions swi f t l y to 10Mbps or 15Mbps, accelerating the popularity of IPTV service. Orange keeps a lead on the rivals by fully exploiting their dominance in terms of copper wire and fiber resources. During mobile network construction, Orange puts network coverage above mobile bandwidth potential.

In contrast, Vodafone is boosting the development of HSPA services in France as part of their strategies to enhance subscriber exper ience with mobi le broadband services over its nationwide 3G network by incorporating mobility into broadband services.

Given the current broadband service environment, an operator providing broadband connections with bandwidth exceeding 5Mbps will find it difficult to balance cost and benefit. For this rea son, Vodafone prov ides average

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Editor: Xue Hua [email protected]

To e f fec t ive ly implement bearer network solutions, we need to examine the current status and capabilities of operators’ bearer networks.

Restricted by a small network scale and gloomy subscriber growth outlook, some mobile operators choose to lease circuits from fixed network operators or other mobile operators to provide bearer capabilities.

For example, as a fresh mobile operator in the European market, Hutchison 3 has concentrated its limited resources on 3G operations, hoping to establish a unique competitive edge in 3G operations within a short timeframe without spending much on complex network construction and wants to bypass the network bearer issue in European countries. Hutchison 3 believes that it needs only to rent circuits to deliver bearer network capabilities without concerns over network planning, construction and maintenance, without the hassle of choosing between optical fibers, microwave and copper wires or between SDH and wavelength technologies.

British Telecom (BT) has a totally different approach. Though not a mobile operator, BT leases its networks to almost

all the mobile operators in UK. BT serves as the bearer network provider for all mobile operators. With a strong team of bearer network construction and O&M engineers, BT can deliver optical fiber and copper wire coverage throughout the UK. Even so, BT is also at risk of losing revenues from leased lines as mobile operators are beginning to construct their own bearer networks due to the open regulatory policies.

The value of Vodafone’s mobile bearer network is quite different from BT. Because of increasing competition and its operational strategy, Vodafone has pumped investment into bearer network construction over recent years rather than providing bearer network capabilities based on leased circuits. They expect to deploy their own bearer network in the shortest possible time. This saves considerably on rents and responds more rapidly to mobile operation needs without relying heavily on other operators’ network resources.

Appropriate networking modes for different operators

The preceding shows that operators tend to select different mobile bearer network solutions to fit their different mobile systems, operational strategies, and bearer networks.

Leasing bearer networks

Quite a few mobile operators such as Hutchison 3 choose to lease bearer networks to expand their bearer capability. For leasers of bearer networks, the ability to pay rents outweighs bearer network planning, design and O&M capabilities.

Providing bearer networks

Many fixed network operators, such as BT, FT, and DT, can profit from leasing bearer networks to mobile operators. Such fixed network operators are described as integrated operators or mobile bearer ne twork p rov ide r s . They focus on providing leased lines that match mobile operators’ development strategies based on

their current network infrastructure while at the same time securing sizable profits and market shares.

As integrated operators, they need not worry about planning and construction of mobile bearer networks, but need to keep reducing costs while responding to mobile operators’ varied strategies and complex network situations. Thus, the highest priority is placed on an open, compatible mobile bearer network with integrated management and maintenance capabilities.

Self-constructing bearer networks

Many operators, such as Vodafone, China Mobile, etc. , construct their own mobile bearer networks. However, these operators are very concern about the network planning, operation and maintenance. Having a partner that is able to provide E2E network-wide solutions can help significantly reduce their network planning, construction and O&M costs.

Mobi le operators usua l ly do not have a large-scale existing network like fixed network operators and as a result, provide opportunities for green field construction. Pursuing a leading mobile broadband strategy, mobile operators feel more compelled than others to construct a future-proof network platform and are more inclined to adopt new technologies.

For operators that want to construct their own bearer networks, the mobile bearer network delivers the most value in cost reduction, improved market responsiveness and QoS. Technically, the network promises to support rapid technology deployment, simple network maintenance, advanced technologies and future evolution.

In conclus ion, we must examine operators’ different operational strategies and their demands for bearer network capabi l i t ies . Natural ly, core values, network configurations, and the selections of technologies relating to their mobile bea re r ne twork s va r y l a r g e l y w i th different operators. Only by addressing a combination of related factors can operators find a mobile bearer network solution that genuinely brings commercial value.

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Backhaul technology in the IP eraAs base station backhaul transforms to IP, transmission is switched from circuits to packets in order to efficiently carry multiple mobile broadband services and reduce operators’ OPEX ready for the IP era.

By Liu Xiheng

its continuous technological and protocol optimization. Indeed, most operators currently deploy MPLS PTN devices for mobile backhaul networks.

PWE3 tunnel is adopted in the MPLS PTN to ensure that the bearer layer is unified and compatible with the TDM and ATM services of traditional mobile 2G/3G base stations. PWE3 transmits TDM, ATM, or Ethernet services in backhaul and simplifies base station access to IP bearer networks.

The PTN is structured in a similar way to the hierarchical rings of SDH networks, which reduces overa l l maintenance complex i ty. For s e r v ice s , the PTN utilizes star path planning with DiffServ technology to implement cross-service QoS between base stations. PTNs use the simple and reliable 1:1 LSP protection mode.

The PTN uses a hierarchical OAM design that covers Ethernet or POS links, MPLS tunnels, PWE3 tunnels, and Ethernet services, providing OAM information at each level of the entire network. The PTN supports future-oriented LTE, large-capacity packet convergence and IEEE 1588v2 clocks. For the X2 interfaces of the LTE eNB, PTN provides L2/L3 switching. Visualized end to end (E2E) network management enables rapid E2E service configuration and, with the OAM mechanism, the PTN can quickly locate board and port faults within minutes.

MPLS already transports packets on telecom networks due to improved telecom features. PTN is in fact an extension of MPLS at the base station access layer for

Backhaul technology in the IP era

Backhaul goes IP

P-based multi-service applications are pervading mobile communications. Bottlenecks are created in SDH backhaul networks as broadband

access become dominant in base station backhaul; SDH’s insufficient capacity, low efficiency, and costly data service interface are gradually becoming evident.

The transformation of base station backhaul to IP marks both network evolution and a technological revolution. The capacity and efficiency of base stations are greatly expanded and improved after IP bearer network access is achieved, and resulting costs are easily controllable. In this scenario, per shelf capacity ranges from 500G to 1T, network transmission is raised to 40GE, and statistical division multiplexing improves efficiency by 50%.

However, IP base station backhaul presents some risks, and minimizing these is a current industry priority. An IP network requires a free and open information structure, which threatens the immediacy, reliability, and manageability of base station backhaul.

One leading European operator decided to replace its legacy SDH/PDH networks with Huawei’s customized IP bearer network solution for base station access, as opposed to a pure Ethernet or router solution. The operator reasoned that IP transformation would deploy 300,000 base stations globally, and that these should fulfill a number of functions: improve efficiency; be future-

oriented, and guarantee service provision, stability, and ease of management.

A detailed study of IP bearer network characteristics in terms of base station access reveals that unified bearer, hierarchical and multi-domain networking, and visual management are preconditions for the large scale deployment of IP bearer networks with mobile base station access. Compared with a DSLAM metropolitan broadband network, these characteristics are more important than the IP protocols used for multiple service provision. Nevertheless, many focus only on technical maturity and ignore the inherent attributes of mobile IP bearer networks. This does not help operators avoid risks in base station backhaul IP transformation.

MPLS hits the mainstream

IP/MPLS or Ethernet switching can be employed to realize IP transformation. MPLS, transport MPLS (TMPLS) and provider backbone transport (PBT) are major transport technologies that can be identified as PTN technologies. These technologies implement QoS management for base station backhaul, hierarchical and multi-domain networking, and visualized management.

Each technology has its own advantages and disadvantages. Commercial circumstances have restricted the development of TMPLS and PBT for IP bearer networks that deliver mobile base station access. MPLS is now the dominant technology thanks to

I

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large-scale networking in terms of hierarchical and multi-domain networks, visualized management, and clock systems. The PTN uses MPLS routers to meet the needs of IP bearer networks with mobile base station access, which eliminates mobile operators’ concerns regarding IP transmission.

PTN devices are now the leading choice for customized IP bearer networks with mobile base station access. Xu Rong, a researcher for China Mobile, believes that PTN provides a variety of carrier-class network features and greatly reduces CAPEX and OPEX. Thus, PTN has emerged as the only option for the IP transportation of base station backhaul.

Future transformation strategies

The rapid development of mobile broadband services has encouraged many operators plan to deploy LTE networks, and some are already constructing FMC networks. In this sense, IP transformation of mobile base station backhaul must consider LTE and FMC development.

LTE backhaul

The centralized control of radio network controllers (RNCs) diminishes in the LTE phase and communication services exist between eNBs and access gateways (AGWs). Base station switchover can be performed between eNBs through X2 interfaces.

Some industry insiders maintain that LTE bandwidth inherits fixed DSLAM bandwidth to support mass P2P services, and that flat IP switching between eNBs transmits services through a large number of routing protocols instead of through carrier-class management. However, this is not entirely correct and is common misunderstanding of IP technological application in the telecom field.

The scale of the Internet and its access scope continue to grow rapidly. Service development demonstrates that MAN base station services are increasingly integrated to enter the Internet backbone network from MAN core nodes. This is also the major reason why LTE standards define that all voice, data, and video service flows enter the

AGW with the S1 interface. The X2 interface is only responsible for switching traffic between base stations. Base station backhaul with flat P2P IP switching is not necessarily required for LTE. If P2P traffic is not considered, a two-level service model of star (S1 traffic) and mesh (X2 traffic) is formed.

The traffic of X2 interfaces features mesh distribution that is transmitted through L2 MAC or L3 IP switching. X2 interfaces have a logical mesh structure, but the service volume on the X2 interface is relatively low (3% to 5% of network bandwidth) due to the short duration of base station bandwidth switchover. In this case, the cost of independent network-wide L2 or L3 switching is quite high and the network is complex to be managed, leading to integrated L2/L3 switching as the preferred mechanism. In this case, L2/L3 switching usually occurs in the central nodes when X2 services have arrived through designated MPLS tunnels.

In a new backhaul network between base stations and AGWs, service tunnels are thus S1 and X2. L2/L3 switching is implemented in easi ly control led convergence nodes that are less cost sensitive for operators. The mesh-structure traffic of X2 interfaces is realized through logical links. The star links and integrated L2/L3 switching solution ameliorate cost, management, and complex service flow issues in the mobile backhaul network.

T-Mobile has begun to build its LTE-oriented mobile IP backhaul network based on comprehensive research and analysis. The operator will deploy MPLS routers in the central nodes with L2/L3 switching, and deploy end-to-end VLL provisioning for base station access to simplify the backhaul network. This will help to reduce network costs, improve management, and ensure carrier-class control and future LTE development.

FMC bearer network

Numerous mobile operators have sought to increase their competitiveness in various ways; for example, by constructing large-scale Wi-Fi networks, acquiring small or medium broadband operators, or by applying for fixed licenses in the drive to become full service operators. Operators favor combining mobile bearer networks with broadband MANs to

reduce the overall cost of bearer networks, but to do so requires that IP bearer networks with base station access can support future FMC service development, such as IPTV and IP VPN. This poses higher requirements on the traditional backhaul network of mobile base stations.

Notably, FMC bearer network in this situation does not refer to the FMC bearer network for each base station as each MAN incorporates many base stations. FMC bearer network generally refers to combined multi-play IP convergence bearer networks and IP backhaul networks (the PTNs) of base stations.

As PTNs focus too much on tunnel, stability, and management, current PTNs cannot bear multi-play services. Traditional MPLS routers are recommended to implement IP convergence centering on service provision. These convergence routers adopt dynamic or static multicast for IPTV services, implement L2 switching for Ethernet services from fixed networks, provide VPLS and IP VPN dedicated lines for commercial users, and evaluate base station backhaul services as VPN dedicated line services.

The number of base stations is about ten times greater than that found at convergence nodes. If MPLS routers are used for such a large-scale network maintained through command lines, the costs are high, rel iabi l i ty is not guaranteed, and management is complex. Thus, PTN technology is recommended based on service requirements. The entire network can be built with router-based IP aggregation layer and PTN-based mobile base station access, and be managed by a unified network management system (NMS).

By selecting optimum technologies based on services and unifying management, the most effective FMC bearer solution in an FMC MAN combines MPLS routers and the PTN. One leading European operator’s Romanian and Belgian networks employ this solution. MPLS routers improve the IP metro aggregation network’s multi-service provision capability. The IP transformation of base station backhaul enhances service provision, fortifies management, and facilitates low-cost base station expansion; mobile bandwidth competitiveness is thus greatly improved.

Editor: Xu Peng [email protected]

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IP backhaul for FMCBy Liu Dong

Amid the FMC tide, questions arise about whether and how the FMC IP Backhaul can truly help operators realize their convergence goals.

MC is becoming a dominant networking trend, which generates n e w d e m a n d s o n n e t w o r k s including the service transport

network.Operators who allocate most of their

transmission investment to mobile backhaul and fixed broadband access networks can cut the TCO and enhance their future-proof long-term competitiveness by adopting IP technology, introducing cost-effective, high-bandwidth Ethernet interfaces, and building FMC capabilities into backhaul networks.

Relevant technical requirements

The mobile backhaul capability is designed to support smooth evolution and unified bearer capability in networks. Mobile base station interfaces have evolved from TDM, to ATM IMA and then to Ether/IP capabilities to support 2G-based GSM, 3G-based UMTS, 3.5G-based HSPA and 4G-based LTE. As evolution is a long and gradual progress, in the current network, different generations of base stations are often found at the same site.

The mobile backhaul network must provide bearers for TDM, ATM, and IP base station interfaces on a unified IP packet network and support high-quality clock synchronization.

Due to the shortage of fiber transmission resources, operators have to use or lease E1 private lines, microwave or even DSL lines at most mobile base stations. This makes it vital for backhaul equipment used at base

F

IP backhaul for FMC

stations to support various transmission lines like optical fibers, microwave and copper wires.

Fixed broadband access places high priority on service implementation and control. It covers a range of areas, including a connection model (for P2E services like VoIP and HSI, P2MP services like IPTV, and MP2MP services such as enterprise VPN lines) , access planning (QinQ plan, and L2/L3 VPN), transmission optimization (traffic model, scalability, and QoS), and service control (user authentication and billing). EoMPLS and carrier-class metro Ethernet technologies have ideally addressed the issues discussed above. Fixed network-based VPN line and family Triple-Play services are gaining popularity.

PWE3 for FMC IP Backhaul

There are still a number of challenges when the f i xed and mob i l e bea re r capabilities are integrated into a physically unified packet network to support FMC.

Each generation of mobile base stations is a separate logic domain requiring unique connection bearers and physical interfaces. Each fixed network service also generates a separate logic domain requiring different service models and forwarding capabilities. Services previously carried over a number of networks must now be delivered on one network that adapts to various technologies and convergence has complicated the situation.

Fortunately, operators and equipment vendors have deve loped the PWE3 tunneling technology for unified MPLS LSP forwarding, which ideally resolves these tricky issues. As a standard sponsored by IETF, PWE3 is fully known as pseudo wire emulation edge-to-edge.

PWE3 transparently encapsulates original interface information into the PW-PDU and provides a control word to convey key requirements contained in the original packet. In this way, the PWE3 technology can fully retain original interface properties and transport information transparently. Rather than using multiple technologies, including TDM, ATM, Ethernet, and MPLS, for service forwarding, multiple PWE3 tunnels employ the same LSP for ward ing t echnology and can be multiplexed into the same LSP, significantly helping to improve overall networking performance.

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Various MPLS VPN tunnels that use MPLS LSP for forwarding can support flawless interconnection with PWE3 tunnels. The PWE3 solution relies on these L3/L2 VPN tunnels to deliver flexible switching and routing capabilities with the LSP, supporting logical topologies necessary for various services. The PWE3 technology matches mobile bearer requirements for different stages of technological evolution and provides the flexibility of fixed services.

FMC IP Backhaul is totally feasible as the technology is neither complicated nor unclear. Essentially it is intended to isolate logic domains on a unified packet network infrastructure.

Two viable solutionsWhen constructing an FMC IP Backhaul

network to replace the costly and inefficient E1 transport network and deliver mobile and fixed services, operators must address key network requirements and determine the network equipment and overall plan.

E2E convergence solution

On most operator networks, only 20% of the sites, such as the urban core and convergence nodes and some suburban convergence nodes must provide access to both fixed and mobile equipment. The remaining 80% only needs to deliver mobile access. For example, there are almost no fixed subscribers along an expressway, but a large number of mobile base stations need to be deployed.

Up to 80% of the remote sites used most ly for mobi le coverage should preferably use small and cost-effective box-type MPLS routers that provide abundant TDM, ATM and Ethernet interfaces. The remaining 20% of the core and convergence nodes must provide fixed and mobile coverage and have E2E PWE3 tunnels for connection with remote access equipment. High-end rack-type MPLS routers that deliver high performance and rich switching and routing features can serve the needs.

All backhaul equipment can then be centrally managed through a unified network management (NM) system and support visualized equipment and service management capabilities, such as setting up

PWE3 tunnels and LSP forwarding paths.In this E2E convergence solution,

PWE3 technology delivers mobile and f ixed service bearer capabi l i t ies . As fixed and mobile services converge at convergence and core nodes, all devices operate in the same mode and under a unified NM system. Leading mobile operators such as Vodafone place a high priority on the backhaul TCO and they expect a simple, unified technology and a cost-eff icient O&M model. These operators highly recognize the solution that delivers multiple services over E2E PWE3 tunnels. Vodafone has proposed the BEP plan, which describes a typical example of E2E IP backhaul convergence solution.

Gateway overlay solution

Some operators already have a metro Ethernet (ME) to carry fixed broadband services. What is the best for establishing an FMC IP Backhaul network?

A new network may incur extra O&M costs and there might be no need to extend ME coverage to all mobile base stations. This is because 80% of the remote mobile base stations do not necessarily need feature-rich ME equipment that support complex networking and it is still technically difficult to build cost-competitive TDM and ATM interfaces into traditional ME equipment.

One so lu t ion i s to u se box- type equipment at remote mobile base stations and rack-type equipment at core nodes respectively as gateways for base stations and base station controllers at both ends of the ME network. Then, set up PWE3 tunnels on the ME network to transport mobile base station traffic transparently. The ME network only needs to have standard Ethernet interfaces, but eliminates the need for an ability to sense or handle PWE3 tunnels that overlay the network.

This approach fully utilizes the existing ME and transparently overlays base stations with backhaul capability, making the maintenance interface simple and clear.

The integrated service operator Deutsche Telekom has T-Mobile and T-Home delivering mobile and fixed line services. Under T-Mobile’s IP backhaul planning, gateways

are deployed on both sides (BTSs/Node Bs and BSCs/RNCs) of T-Home’s current ME network to deliver FMC capabilities through the gateway overlay solution.

Further considerationsIs there still a need to deploy IP backhaul

access equipment next to base stations since the latest base stations can support Ethernet and IP interfaces?

80% of remote base stations have poorer equipment room and fiber conditions than core and convergence nodes. Moreover, as the latest IP base stations fail to provide TDM or ATM interfaces, they cannot support access and convergence for traditional TDM and ATM base stations. As a result, backhaul equipment is still required to deliver unified access for fixed and mobile services and provide SLA monitoring, OAM and the protection switching capabil i t ies necessary for networking. Special-purpose backhaul equipment also provides clear maintenance interfaces for an operator’s mobile and transport departments.

The FMC IP Backhaul solution also supports a range of packet clock technologies, such as IEEE 1588v2, ACR, NTR, and synchronous Ethernet, which deliver clock synchronization for mobile services. The GPS-level clock (frequency and time synchronization) adapts to more applications and the resource reservation protocol (RSVP) enables the network to set aside sufficient resources for high-value mobile services.

The so lu t i on a l s o in c re a s e s th e efficiency in QoS parameter planning and management for the current ME network. Combined with f lexible schedul ing technologies, such as H-QoS, the solution can deliver the QoS required for various FMC services.

Through PWE3 tunneling technology, the FMC IP Backhaul solution incorporates various service logic domains into a unified data packet network transparently and uses a visual unified NM system to realize equipment management and service provision.

As an industry leader, Huawei integrates EoMPLS+ carrier-class MAN technology into its IPTime mobile bearer solution, helping operators achieve FMC through E2E solutions that suit various networking scenarios.

Editor: Pan Tao [email protected]

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Mobile backhaul strategies for emerging markets

Backhaul challenges and strategies

DM-based a rch i t ec ture has traditionally met the requirements of 2G operators. Several major operators such as Vodafone, FT/

Orange, Etisalat, MTN and Zain are still investing heavily in the expansion of their 2G mobile networks. Thus, the increase in traffic volumes and the pressure of new service deployment demand an exponential growth of bandwidth on backhaul networks.

The gradual migration from 2G to 3G will definitely lead to long term co-existence of the two networks, which in turn poses a challenge in backhaul to support the multi-service transport requirement for a longer duration. This leads to a requirement to bear native TDM services, plus TDM + Ethernet services and IP in the future.

Operators in this case, bear a high cost for capacity expansion in SDH networks, leased lines and microwave equipment. This leads to a need to improve transmission media to accommodate the increased service demands.

Mobile operators are facing considerable operat ional chal lenges as they seek to maintain their existing networks with multiple backhaul technologies, including PDH&SDH Microwave, SDH multiplexers, and regional WDM technologies. The evolution to 3G backhaul creates additional hurdles that lead

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By Madhav Bhatta

Emerging markets have become an intense battleground for multinational mobile operators with their strategy to enlarge their global footprint. These operators are facing enormous challenges to build the backhaul networks with their TCO efficient and quick time-to-market strategy. This article identifies the challenges to build these backhaul networks and recommends the potential solutions from a technical and business perspective.

Mobile backhaul strategies for emerging markets

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Some of the measures that could be looked into are:

• One NMS for one backhaul

One unified NMS for each backhaul greatly simplifies daily operations. The solution features a complete point-and-click function that defines traffic routes between BTSs/Node Bs and RNCs/BSCs. It avoids multi-segment provisioning to reduce repea ted addi t iona l l ink configurations.

The NMS covers up for all equipment such as SDH, MSTP, WDM, microwave and even packet backhaul, to reduce the cost in maintaining different teams with separate products.

• Accelerated troubleshooting

Rapid troubleshooting is a key focus for major operators aiming to reduce the numbers of site-visits, minimize network interruptions, and implement preventive maintenance. Multi-segment configuration is the major factor that increases on-site engineering tasks and hinders failure location.

However, simply deploying a single unified NMS is insufficient; an alarm correlation system is necessary to clarify fault definitions throughout the network. Alarm correlation DB uses aggregation rules to generate root and non-root alarms, and can suppress 90% of the non-root alarms to quickly locate the root causes. Ethernet layer OAM also assists in monitoring E2E service connectivity and links status.

• Fewer on-site visits

Cellular networking is growing very fast, requiring quick rollout of mobile base stations. This brings the need for regular capacity adjustment, upgrade and optimization. Hence, field engineering becomes another important aspect of operational challenges. This situation can be ameliorated by flexibly configuring E1, IMA E1, and FE through card level , software programmable radio (microwaves), and a built-in add-drop mechanism.

Moreover, field visits can be further reduced by using the hot patch technology

to high TCO in the short- and long-term.The main challenges that increase the

TCO of 2G operators on their existing backhaul networks are analyzed below.

Challenges on stacking many boxes

Approx ima t e l y 80% o f e x i s t ing backhaul networks comprise legacy PDH, SDH microwave links and multiplexers stacking many PDH, SDH boxes in coexisting sites. This increases the CAPEX as well as operational difficulties.

Existing TDM backhaul modes may meet immediate day-to-day requirements. However, in the event of adding more subscribers or even migrating to 3G, there will be a need to rebuild or introduce a new backhaul technology, leading to more boxes within the network to sustain the increased traffic. It would then become difficult to have an overview of the whole network. In addition, the problem of maintenance as well as efficient media transfer could also arise.

Nevertheless, a series of steps exist to address these problems.

• Reduce complexity via unified solution

Huawei intends to solve operators’ complexity arising out of stacking many boxes in their networks with flexible so lut ion equipped with divers i f i ed interfaces in an integrated solution. The existing stack of SDH boxes can be easily replaced by a single highly integrated MSTP platform.

Fo r e x a m p l e , M S T P b o xe s a n d microwave indoor units (IDUs) support in t eg r a t ed mic rowave and op t i c a l networking features. Microwave RF card is pluggable to either of these boxes. Hence, there is no requirement for MUX and DDF in Hub Sites, and no cabling is required. These features ensure higher reliability, flexible networking, faster service provisioning, and less equipment.

• Support all backhaul scenarios to avoid stacking

Given the long-term nature of 2G, 3G, and HSPA co-existence, the backhaul solution should be applicable in diversified

scenarios to avoid stacking boxes. To meet the growing demand of 3G services, ATM IMA can be plugged within the same box thus avoiding stacking of ATM switches. Native E1, IMA E1, and FE interfaces at cell sites offer seamless access of cell sites and network aggregation. On the RNC side, a single piece of equipment can support STM-N, ATM STM-N, and FE/GE interfaces to cover all the scenarios of RNC-side aggregation.

Each of these features needs to support card level expansion to enable faster deployment and realize the rapid TTM requirement of cellular networks. Directly upgrading from an existing system incurs less CAPEX and is easier to deploy. A single network management system (NMS) operates the whole network with less O&M demands, and thus less manpower.

Daily network operation challenges

In 2007, Huawei had an opportunity to join with FT/Orange to analyze the TCO for emerging markets targeted by 30+ Orange affiliates. The major findings revealed that the excessive OPEX was derived from managing different network platforms; in particular the cumulative costs associated with human resources, power consumption, and floorspace.

It is extremely difficult to locate failures across multiple network management platforms that lack both E2E provisioning and unified performance monitoring mechanism as it makes the troubleshooting extremely complex and cause high OSS integration costs.

In medium-level operators’ networks, thousands of alarms are generated daily by backhaul equipment. However, alarm correlation techniques to determine faults over multiple network platforms such as microwave, SDH, etc., are absent. This delays rectification of faults. The need to maintain multiple maintenance teams of engineers without a unified NMS will hamper quick fault detection and have adverse effects on the OPEX of the operator.

Opera tor s can take a number o f m e a s u r e s i n t e r m s o f s i m p l i f y i n g operations and reducing O&M costs.

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to fix bugs, online software to remotely upgrade NEs, and the NMS to monitor remote optical power. The point-and-click and E2E provisioning also eases the burden of site-by-site configuration, previously shouldered by engineers.

• Cut inventory and spare parts

Unified hardware and software makes all service cards compatible with the products applied to core sites for access and aggregation. When configured for specified distances, the flexible SFP pluggable optical module reduces the expenditure on spare parts, and the same principle applies to microwave IDUs, ODUs, antennas, and RF couplers. These features can be combined to minimize the TCO network-wide.

Cost of reality & future challenges

2G mobile operators are confronted with the challenges of finding effective ways to evolve to 3G/HSPA while lowering OPEX and CAPEX. The optimum choice must involve minimum costs and reuse of existing network resources to bear legacy services, provide 3G/HSPA services, and ensure seamless future expansion capabilities. Predictably, the various potential solutions lack clarity and pose great challenges for operators.

For example, increasing investment in legacy service provision with the hope of a delayed migration to all packet platforms in the future is broadly a short-term expedient.

On the other hand, rushing to acquire a nascent technology that applies to a separate IP platform will not only incur a high and immediate CAPEX, but also pose operational problems for teams who are currently accustomed to legacy microwave and SDH networks. In terms of emerging markets, the latter approach requires specialized and highly skilled networking experts, who are currently very few in the market.

The overlapping nature of legacy and nascent technologies raises questions for operators regarding when, how and which technology to apply, to realize backhaul for the new RAN.

Huawei’s recommended strategy is based on the unified solution that simultaneously supports TDM and packet to seamlessly transport 2G and 3G or HSPA data services. We recommend the evolution strategy rather than revolution. This means the smooth evolution from MSTP to MSTP+ solution is proposed instead of the need to build an overlay network.

At the cell site gateway, TDM microwave network can be smoothly upgraded to hybrid microwave

to achieve seamless Ethernet access. This can be achieved by simply adding RF cards into the existing RTN equipment. The upgraded solutions can effectively utilize the same IDU and ODU and can access services such as IMA, TDM and Ethernet.

MSTP+ and hybrid microwave can be smoothly evolved by replacing cards that enable rapid deployment and rollout of 3G networks. This saves considerable CAPEX and OPEX, as well as enables the operator to recoup ROI on legacy investments.

E2E backhaul solution for emerging markets

In the technical context of 2G/3G coexistence and the backdrop of continual network and service evolution, Huawei has designed its solution to meet current requirements and seamlessly evolve into future pure packet platform architecture.

From the perspective of strategic business models, Huawei’s TCO analysis report maintains that operators’ primary goal rests in achieving TCO reductions. In this sense, the MSTP-based solution is irrefutably cost-effective, suitable for different application scenarios, and simplifies O&M.

Huawei proposed its mobile IP RAN backhaul solution to respond to the current dominance of TDM traffic in 2G networks, the massive amount of data involved with 3G services, and the inevitability of future All-IP migration. The solution also incorporates legacy TDM strengths–such as OAM, performance monitoring, and so on–to maintain the operational experience of existing operation teams without requiring CCIE networking expertise.

In the light of the various challenges in the emerging markets, Huawei has considered a multi-layer TCO reduction approach to systematically reduce OPEX and CAPEX.

Following Huawei’s technical and economic analysis and discussions with numerous operators regarding emerging markets, FT/Orange, China Mobile, China Unicom Beijing, StarHub Singapore, Digi Malaysia, Excelcom Indonesia, Wind Italy & Orascom Group, and MTN plan to implement Huawei’s solution in their networks.

As a leader in E2E mobile backhaul solution, Huawei is well-placed to confidently overcome the challenges faced by 2G operators in running existing networks, and evolving to 3G network. Huawei believes that the proposed solution will eventually bring a 30% to 40% reduction in TCO.

Mobile backhaul strategies for emerging markets

Editor: Joy Zhou [email protected]

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Enabling easy mobile bearer O&M

By Cui Jinguo

Due to prevailing IP networking trend and urgent demand and growth in mobile data services, network maintenance has become increasingly complicated. As a result, operators have been forced to shift their operation and maintenance (O&M) focus from equipment to services.

32

O&M challenges from IP-based mobile bearers

Managing diversified access

r e v iou s l y mob i l e ne twork s t r a n s p o r t e d s e r v i c e s v i a a s ingle medium, which made maintenance more straight-

forward and simplified. However, due to the gradual transition to broadband networking, more access means have now become available and base station coverage requirements have also become

P

increasingly varied. Tightening regulatory policies, growing

coverage, rising costs, and increasingly varied terminal applications have all contributed to cause greater diversity in regards to access means at the base station level. Given the current trend, the door is now wide open for the possibility of fibers, microwave, copper wires or the Ethernet to be used to del iver mobile bearer capabilities. In this case, operators face the daunting challenge of maintaining and managing various types of bearer media.

Optimizing packet bearer channels

The end to end (E2E) IP -ba s ed bearer channel represents one of the major objectives of IP-based E2E mobile networking. Since IP networking requires a long period for development, TDM and packet services will coexist in the long term. Mobile data services require and consume most of the current ly available bandwidth for packet services. The traffic that these services generate is presently considered to be abrupt and discontinuous. Furthermore, IP networks provide connectionless and best-effort services, creating many uncertainties to the proper management of bearer channels.

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Enabling easy mobile bearer O&M

I f proper management o f beare r channels is to be achieved, then IP-based bearer networks need to incorporate O&M expertise from traditional SDH and multi-service transport platform (MSTP), and integrate the expertise into connectionless bearer network management. This in turn will help to prod operators to improve their E2E service management and quality control abilities.

Increasing NMS intelligence

Varied frequencies and data service requirements of different commercial districts have contributed to the density of base station coverage. As a result, the number of 3G base stations may be twice the number of currently operating 2G base stations in the near future. In the initial stage of 3G construction, 80% of all 3G base stations will be able to share sites with 2G base stations.

The maintenance mechanism and network management system (NMS) should also be able to support both 3G and 2G service bearers. This requires the O&M system to be able to support more complex, but flexible configuration and control of multiple service types, as the OPEX is reduced. The system should also provide abundant fault detection methods to prevent, quickly and accurately locate, and effectively resolve problems for subscribers, thus, helping to increase

subscriber loyalty in the process.

Progressive O&M evolution

Network O&M cost i s genera l ly believed to be 3 to 4 times as high as network building cost. Consequently, the need continually arises for mobile operators to reduce O&M costs. Their first reaction is generally to minimize their O&M workforce through automation and information technologies. However, most operators are hesitant to accept substantial O&M transformation in order to protect their investment and control costs . Therefore, network O&M evolution is a progressive process.

Unified management

As mobi le bearer network access becomes increasingly more diversified, integrating NMS technically will make O&M tasks more complicated and create more maintenance boundaries, thus blurring the division of responsibilities.

Integration sets the trend for mobile bearer NMS. An integrated NMS will be capable of managing multi-access bearer networks, reduce the cost of multi-technology NMS integration, and be able to substantially minimize the number of O&M boundaries created by varied technologies,

hence generating a more holistic mobile bearer network in the process.

Moreover, the integrated IP mobile bearer NMS must be able to reduce technical barriers, minimize network complexity, and lower the technical thresholds for O&M staff. Given this trend, previous NMSs will be able to be more smoothly upgraded to support O&M integration, reducing the NMS cost incurred by new technologies.

Visualized maintenance

With the continued deployment of 3G mobile services and extension of network coverage, IP-based bearer networks are increasingly facing the challenge of inheriting robust O&M capabilities from SDH and MSTP bearer networks.

IP bearer networks differ largely from SDH and MSTP bearer networks in the current O&M model, as IP networking is connectionless and provides best-effort routing. Moreover, command line-based O&M has more or less raised the technical barriers for the typical O&M staff and reduced the possibility of inheriting O&M capabilities. Most O&M staff are usually not very clear in regards to their IP network status. For them, IP networks have become obtuse and cloudy and hidden behind mountains of technical barriers, thereby causing internal routes to become more obscure and invisible.

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Carr i e r - c l a s s O&M nece s s i t a t e s a tendency towards more visual ized maintenance. The cloud of mystery su r round ing IP ne twork s mus t be dissipated, so that O&M staff can see them more clearly.

Huawei’s O&M solution incorporates innovative IP networks research results, thereby enabling O&M staff to dispel any cloudy areas and develop a clearer picture concerning their IP network status. The solution also helps to facilitate the evolution from a passive to more active IP network O&M and provides a graphical presentation of maintenance channels and indicators. This in turn helps O&M staff to maintain bearer networks in a more proactive manner and also safeguards the delivery of mobile services.

Moreover, this solution relieves O&M staff from the heavy burden of continuous attendance. This allows them to shift their attention to preventative maintenance and network optimization, clear equipment risks, reduce faults, improve network quality, and raise overall network O&M efficiency.

As one of the earliest adopters of IP networking, China Mobile previously assigned many O&M employees the task of maintaining its transport equipment, but more recently it has begun to realize the increasing difficulty in maintaining an IP network through command lines. Therefore, Huawei’s solution, which supports visualized IP network O&M and

graphical operations, completely satisfies China Mobile’s requirements of lowering IP network O&M thresholds, and also enables O&M staff to reshape competencies.

Decoupled O&M

Built on a massive infrastructure, mobile bearer networks are geographically distributed across vast areas to form a complex network s t ructure . This circumstance further requires that the NMS should cover all network elements (NEs) through ful l decoupl ing and abstraction.

There has recently been a rise in NMS modules being loosely coupled and deployed in an increasingly distributed manner. This type of solution is proving to be idea l for l a rge- sca le network management and for the use of portable NMS modules, which supports single-s i t e maintenance and management and increases the flexibility of O&M. Moreover, the solution is quite capable of satisfying O&M requirements across reg ions and network segments . By expanding per capita O&M coverage and reducing the O&M workload and complexity, the solution literally paves the way and makes it much easier for operators to generate more profits, and at the same time allows operators to respond rapidly to subscriber requirements.

In addition, hierarchical service-centric

management helps to reduce management complexity and map subscribers and services with the appropriate bearer channels. This in turn enables O&M staff to per form E2E detect ion and maintenance, minimize troubleshooting time, increase troubleshooting efficiency, and helps improve analysis of causes and service impacts, achieving a more subscriber-oriented O&M focus.

Driven by a combination of factors such as technology, competition, and business transformation, IP-based mobile bearer network management is increasingly shifting its focus from equipment to services, and from distributed to centralized operations. Moreover, O&M efforts are becoming increasingly more scientific, automated, standard, and information-based. Further, the O&M organizational structure is becoming more flattened and simplified as time goes on.

The IP-based mobile bearer network management is likewise shifting its focus from QoS to QoE, from a more extensive to leaner management style, and from a functional management approach to a more process-based management approach. Only in this way can operators increase O&M cost-efficiency, improve network prof i tabi l i ty, and enhance subscriber experience, thus creating a win-win situation for operators and subscribers alike.

Editor: Pan Tao [email protected]

The need continually arises for mobile operators to reduce O&M costs.

Their first reaction is generally to minimize their O&M workforce through

automation and information technologies. However, most operators are

hesitant to accept substantial O&M transformation in order to protect

their investment and control costs. Therefore, network O&M evolution is

a progressive process.

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OAM in the IP bearer era

Ever-evolving OAM requirements

Reporter: What changes will occur in bearer network O&M during the rapid shift to IP?

Boris You: Consumers expect ubiquitous broadband and diversified mobile services in 3G. Meeting the demand for new services, 3G with its accompanying high traffic volume brings not only additional profit streams, but also a big challenge for operators. At the same time, network OAM also needs to change.

Generally, one base station requires 1–3 E1 links to bear traditional mobile voice services. Evolution to LTE requires a bearer network with a bandwidth of 100M and the wide application of packet transport technology. In large city nodes, wavelength division devices need to be located on the access side to ameliorate the problem of limited optical fiber trunks. Microwave will play a greater role where cable deployment is difficult. Basically, IP bearer networks require many more types of devices, which will complicate OAM, network planning, and network management.

IP network’s connectionless nature causes a large number of problems in IP network management, maintenance, and QoS guarantee, as the IP service is both abrupt and discontinuous. It means that networks must be optimized more

Mobile bearer networks are expanding rapidly to accommodate the burgeoning growth of mobile Internet. This brings a series of challenges that need to be addressed: How can the network management system (NMS) provide an optimum but inexpensive control mechanism in the All-IP era? How can operation, administration, and maintenance (OAM) skills be enhanced for operators on mobile bearer networks in order to keep pace with IP transformation? With these questions in mind, COMMUNICATE met with Boris You, President of the Huawei Network OSS and Service Product Line.

frequently as they gradually expand, with new service offerings, increased bandwidth demands and additional nodes.

During festivals or big events, more services or the temporary cutover of services to other Node Bs are needed for emergency communications. When traffic returns to normal levels, circuits will be restored to their original state. Therefore, end to end (E2E) OAM in bearer networks needs to be undertaken rapidly and at low cost to cater for more services and traffic peaks.

Reporter: As the control point in the OAM of mobile bearer networks, what are the capabilities and characteristics required for the NMS?

Boris You: The IP transformation of networks brings higher requirements on the NMS. While operators obtain profits from higher bandwidth and improved performance, network monitoring complexity increases. High-ARPU customers have strict requirements on service quality, low failure rates, and rapid fault recovery. The NMS must provide a visualized OAM interface that can rapidly locate inter-domain faults and implement cross-layer service scheduling. Network problems should be solved in advance to improve customer experience.

Future FMC network evolution demands a unified NMS which can enhance OAM capabilities and meet operators’ needs for lower OPEX.

However, OAM is not an easy task amid IP transformation.

Huawei OSS and Service Product Line has been established to closely follow network development trends and customer demands, and familiarize us with the new features and requirements of mobile bearer OAM. Based on our extensive R&D resources and experience, we have innovated our unified NMS for our customers around the world to meet their convergence and joint management requirements.

Unique value for operators

Reporter: What unique value can Huawei IP OAM solutions bring to operators?

Boris You: Currently, IP network OAM is managed by a command line interface, which is complex and requires highly skilled personnel. In Europe, for example, the cost of a CCIE engineer is three times as a standard network OAM engineer.

Our NMS solution provides visual management to simplify maintenance and enhance management efficiency through static maintenance over dynamic networks. By clicking on the network topology view, OAM staff can easily deploy services, monitor networks, and locate faults. Technical complexity and labor costs are reduced and existing OAM teams can

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INTERVIEW

JUN 2009 . ISSUE 50

Huawei OSS and Service Product Line has been established to closely follow

network development trends and customer demands, and familiarize us with

the new features and requirements of mobile bearer OAM.

——Boris You, President of the Huawei Network OSS and Service Product Line

maintain IP mobile bearer networks after basic technical training.

Most existing bearer networks use optical transmission devices such as SDH. To erase the OAM differences between IP and traditional bearer networks, the Huawei NMS unifies operations, interfaces, and models. Therefore, there is no need for OAM staff to have extra training or learn specialized skills.

Reporter: How can the Huawei mobile bearer OAM solutions help operators reduce OPEX?

Boris You: There are many methods. The first is to develop network-wide management capabilities. Mobile bearer networks need to manage high volumes of services and distributed equipment, which raises OAM difficulties. A key challenge is to have a unified NMS that can manage all network equipment through E2E management.

Huawei solution can manage any media; it manages a range of equipment over the IP RAN, including IP, optical transmission, and PON devices. With an innovative algorithm, we co-plan microwave and PTN networks based on SDH and wavelength division services. This optimizes network resources utilization and facilitates mobile bearer network planning.

The second measure is to promote E2E service management efficiency. The purpose of accelerating network construction is to seize market opportunities and gain a competitive edge. Therefore, the NMS must provide efficient service management, rapidly access and manage networks, and shorten the time to market of new services. The

Huawei unified NMS realizes E2E service management, scheduling, and monitoring. Service cutover in batches is easy and efficient, and the NMS allows operators to provide and schedule services ranging from a single site to the entire network.

The third aspect focuses on rapid and precise trouble-shooting. The Huawei solution can quickly and accurately locate faults not just on devices and interfaces, but also on each service.

The final point is fast and comprehensive OSS/NMS integration to create a complete OAM system. Huawei has a wealth of experience in OSS integration, and we have built solid relationships with major OSS suppliers such as HP and IBM. Our cooperation extends to jointly establishing and managing labs in Europe and China. So far, the Huawei NMS has successfully integrated with the OSS of 36 of the leading 50 operators in the world.

The Huawei mobile bearer OAM solution combines the four features I have mentioned to effectively assist operators to manage their E2E networks and reduce OPEX.

Market leader and strategic partner

Reporter: Can you explain the commercialization process of Huawei’s mobile bearer OAM solutions?

Boris You: The market has responded better than we anticipated to all of our NMS products, especially our mobile bearer NMS, and massive deployment is also helping us to achieve our business goals.

For example, China Mobile’s bearer networks are mainly SDH and MSTP. As a large number of PTN devices are needed for IP network transformation, the deployment of 3G IP RAN means that the operator’s maintenance teams will face many challenges. After 10 weeks of stringent testing by China Mobile, the Huawei NMS has proven to be highly effective at managing hybrid network. I’d like to cite another example. By the end of 2008, Vodafone has used Huawei unified NMS in over seven of its 3G subnets to unify management and schedule services.

Reporter: What is Huawei’s goal for the OAM of LTE bearer networks?

Boris You: In LTE era, reducing OPEX will remain a big headache for operators. Huawei bearer network OAM solution inherits the advantages of self-organizing networks (SONs) and intelligently configures the X2 interface after base stations are designed to support IP. The solution will also enhance switchover in base stations and optimize VPN configuration on bearer networks. Additionally, we are aiming to make breakthroughs in IEEE 1588v2 precision clock synchronization, visual IP OAM, and LTE bearer network security.

A visualized OAM solution that can manage any media across an entire network is invaluable. It can help operators explore the abundant market opportunities offered by LTE bearer networks. In this sense, we are considered to be a strong strategic partner for operators both in the present and in the future.

Editor: Li Xuefeng [email protected]

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Solution

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Mobile broadband is currently a key part of operator strategy and its development necessitates IP-based mobile base station transmission. In addition to transporting current 2G and 3G services, the IPTime mobile bearer solution helps operators open a new era of LTE-oriented mobile broadband.

IPTime powers mobile broad band

IPTime powers mobile broadband

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IPTime powers mobile broad band

perators are facing a host of challenges like site acquisition, increased transport bandwidth, low-cost clock synchronization

for networks and services, broadband-induced IP network maintenance and fault location.

To help operators cost-effectively transport mobile broadband services and bolster their bottom line, the IPTime mobile bearer solution proves to be remarkably flexible and can accommodate a variety of mobile broadband requirements.

Solution highlights

As 3G networking evolves toward LTE and mobile network operators are battling increasingly homogeneous competition, OPEX threatens to stifle mobile broadband growth. Mobile bearer networks need to face the challenges and hone their future competitive edge. To respond to these new challenges, Huawei has launched the IPTime mobile bearer solution.

IPTime includes the IP microwave RTN equipment series, CX metro router series and the PTN box-type packet transport equipment series, combined to break the broadband bottleneck and deliver end-to-end (E2E) IP mobile transport capabilities. IPTime can elastically support mobile network evolution to LTE as well as transport 2G and 3G services flawlessly.

Any media access

Statistics show that 70% of mobile network costs are spent on sites and auxiliary facilities, while equipment itself only accounts for 30% of total. Transport resources are one of the main factors that restrict site acquisition. To give operators more options for site acquisition and reduce OPEX, the IPTime solution employs an All-in-One Box to provide access via copper wires, fibers, and microwave. This feature supports access in varied scenarios and is a flexible transport option for full mobile network coverage.

Any media synchronization

Due to mobile service roaming and handover, different mobile network

systems must support high-precision clock synchronization like frequency synchronizat ion between GSM and WCDMA systems and phase synchronization between CDMA, TD-SCDMA, and LTE systems.

The IPTime solution fully utilizes various technologies to provide clock synchronization for different applications, and Sync Eth, NTR, and IEEE 1588v2 capabilities to meet clock synchronization requirements in dif ferent phases of network development. This is designed to deliver complete clock synchronization capability and GPS-grade packet clock capabilities for access via copper wires, fibers and microwave.

Any media management

Integrated management is the optimal choice for mobile backhaul networks involving multiple access modes and scenarios. Essentially, the mobile packet bearer network is designed to deliver reliable mobile services rapidly while inc re a s ing mob i l e b ea re r ne twork efficiency and providing future-proof bearer capabilities.

With regard to reliability, the IPTime solution features E2E differentiated QoS and OAM capabilities from end-point base stations to core convergence points to support differentiated service requirements. It also delivers network-wide 50ms carrier-class protection switching which supports star, chain, ring and mesh networking.

In terms of unified and integrated ne twork management , the IPTime solution supports visualized management of IP services, reducing technical barriers for O&M staff to shift from SDH to IP operation and maintenance. Incorporating integrated and visualized management and one-key configuration capabilities, IPTime eliminates the need for existing O&M staff to obtain the CCIE certification that qualifies them for IP operation and maintenance.

Visua l ized network management has a l so s impl i f i ed ne twork O&M considerably, helping operators focus on core competencies. This is especially vital for developed regions that incur high OPEX.

O

By Li Hongsong

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IPTime powers mobile broadband

LTE ready

LTE is designed to eventually deliver f ixed broadband service capabilit ies and is the ultimate objective of mobile network evolution. During the evolution to LTE networking, mobile networks will experience significant changes in terms of mobile broadband capabilities and network architecture.

The LTE system supports All-IP flat architecture when compared with the legacy 3G or HSPA 4-level network structure and has improved broadband service performance while substantially reducing the delay of protocol disposal. IPTime integrates the LTE-ready feature, providing users with an E2E delay as low as 20ms to guarantee broadband service experience.

The LTE-ready solution has also increased the air interface bandwidth to 100Mbps to support broadband services. In addition, the solution delivers E2E QoS and high-speed mobility exceeding 350km/h to adapt to new broadband applications such as high-speed railway transportation and indoor coverage. Its new X2 logical interface supports fast handover between adjacent base stations. These features require that the mobile bearer networks to possess robust adaptability in the evolution towards LTE, support large-capacity access and convergence, time synchronization and L3 forwarding at integrated nodes.

Based on All-IP architecture, IPTime delivers high bandwidth for any access method. In regard to microwave access, the solution incorporates the adaptive modulation capability, which increases the microwave transport bandwidth to 800Mbps in both directions. By using G.SDHSL technology, copper wire access bandwidth is delivered up to 20Mbps and has improved fiber access bandwidth comparab l e to GE capab i l i t y. The solution features PON technology, which improves fiber resource utilization greatly in addition to delivering the required transport bandwidth.

In respect of time delay, the IPTime mobile bearer network provides a one-way delay of less than 5ms meeting the established standard. In terms of clock synchronization, the IPTime solution

incorporates IEEE 1588v2 technology to provide a high-precision GPS-grade packet clock that fully matches LTE’s time synchronization requirements. In terms of the X2 logical interface, the solution supports L2/L3 stepless switching geared to the rapid handover requirement between adjacent base stations.

Mobile bearer networking mode

The mobile bearer networking mode varies between mobile operators. Operators who lease bearer circuits tend to set up a separate E2E mobile bearer network that meets their mobi le broadband requirements. Integrated service operators who possess f ixed broadband metro networks usually want to accommodate their mobile broadband needs via the existing networks. Operators generally choose either to construct a separate E2E mobile bearer network or expand their existing broadband metro networks to provide mobile bearer gateways.

For s epa ra t e E2E mobi l e bea re r networking, mobile operators mainly focus on reducing leasing costs and increasing transport efficiency. Due to the growing demand for large-granularity mobile IP services and network bandwidth, mobile base stations provide an increasing number of FE interfaces, generating an urgent need to use packet technology for service transport.

While delivering mobile services over a separate E2E packet transport network, operators also need to support high-value services, such as private enterprise lines. Packet technology has also created challenges for mobile service delivery and deployment.

The packet transport network must be able to transport high-precision, stable synchronization signals. Although the GPS can support frequencies and time synchronization as required, network security remains at high risk. Operators need to addre s s ne twork prob lems c a u s e d b y t h e p a c k e t t e c h n o l o g y regarding management transparency, troubleshooting, performance and security

management.Expanding existing broadband metro

networks to prov ide mobi le bearer gateways, mobile operators can fully exploit existing metro network resources to ease the associated mobile broadband costs and evolutionary pressures on traditional SDH networks.

Traditional metro networks fail to fully support mobile services. Operators must utilize new packet transport gateways, such as synchronous signal transport and offload to deliver the necessary features for mobile services. These new gateways enable operators to deliver unified mobile service bearer capabilities over their existing metro networks and fully utilize their existing coverage and broadband service capabilities.

Using this mode leaves operators still facing the challenge of renovating existing broadband metro network equipment to construct an FMC-oriented bearer network as mobile broadband services gradually mature.

Geared to the two networking modes, Huawei’s IPTime mobile bearer network solution includes MPLS-based PTN devices, which integrate multiple packet features such as flexibility, scalability and statistical multiplexing, plus transport f e a t u r e s l i k e n e t w o rk E 2 E OA M , protection, connection orientation, QoS and timing synchronization. All these features combine to form a mobile packet bearer network based on All-IP infrastructure.

IPTime supports all access modes and features high-precision packet clock synchronization, E2E carrier-class 50ms protection and 30ms 5-level hierarchical fault detection capabilities. The solution also focuses on sharpening an operator’s competitive edge in sustainable mobile broadband development and considerably reduces OPEX to facilitate construction of LTE-oriented high-quality bearer networks and enhance profitability during the transition to All-IP.

Huawei’s IPTime solution has been widely commercialized by many world-renowned operators, including Vodafone, Telefonica, and China Mobile.

Editor: Xu Peng [email protected]

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Choosing the right technology for mobile backhaul evolution

By Ma Hongzhong

Three technologies

ith the development of technologies such as IP-based base stations, HSPA, and LTE, IP-based mobile

backhaul is gaining in popularity. In the inevitable evolution toward IP networking, mobile backhaul currently has three viable technology options.

The L2 Ethernet solution is cost-efficient, but lacks reliability, scalability, and manageability. This Ethernet-based enhanced provider backbone transport (PBT) technology replaces the MAC address learning, with a central ized network management system (NMS) to manage the forwarding path. The solution also combines Ethernet’s simple structure and low cost, along with the traditional SDH system’s central management and configuration capabilities. However, PBT technology lacks sufficient support from many leading industry vendors.

The L2.5 MPLS technology is the second alternative. As a virtual connection-oriented tunnel technology, this solution easily adapts to various scenarios. For instance, in the metropolitan area network (MAN), MPLS simplifies the Internet protocol for core routers, enhances OAM and protection capabilities, and supports

service monitoring similar to SDH. Moreover, the solution also includes pseudo wire (PW) technology which allows compatibility with traditional TDM and ATM services. In addition, it integrates a centralized NMS which substantially improves MPLS tunnel provisioning and management capabilities.

This solution is currently very popular with many operators and vendors, which means that the L2.5 MPLS solution will increasingly become mainstream in the near future. Despite being one of the L2.5 MPLS solution embodiments, transport MPLS (TMPLS) deviates to a large extent from the current MPLS protocol family, which severe ly hampers the internetworking between current routers and the TPMLS domain. Fortunately, new MPLS transport profile (MPLS-TP) is being developed to address this problem.

L3 routing provides a third option. Networks that are built on L3 routing can easily adapt to more complex traffic models and provide the ability to forward services on the best route. The solution features robust flexibility and high bandwidth utilization. However, a notable drawback of L3 routing is that it works in connectionless IP networking. In this solution, since every service flow is automatically forwarded from a single node, this makes it virtually impossible for network maintenance

Wengineers to determine the flow direction or accurately understand the network status at a given time.

The MPLS standard has incorporated an increasing number of new technologies such as MPLS traffic engineering (TE) and MPLS OAM to make up for these deficiencies. However, this solution still falls far behind traditional SDH technology in terms of its management and maintenance capabilities. In addition, the MPLS/IP router has a rather complex structure, and also costs more than L2 or L2.5 devices. As a result, operators rarely deploy L3 devices covering large areas among base stations.

Which technology is the best bet in the long run? In fact, any of the three technologies listed above, if used alone, is insufficient to ideally carry LTE and FMC services. But one thing is certain. The technology that operators finally decide upon must be able to address the possible impact of the traffic model on mobile access, as well as other factors including service type and operators’ maintenance ability.

Traffic model is a key factor

Backhaul for GSM and 3G

To support a smoother evolution towards IP networking, there are at least three available options for mobile backhaul: L2 Ethernet, L2.5 multiprotocol label switching (MPLS), and L3 routing. So, which one of these options best suits operators current needs and requirements?

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Solution

only to increase the bearer efficiency for only 5% traffic. Nonetheless, in the proper environment, bearer efficiency and manageability can be balanced. Using a traffic model that combines L3 and L2.5 capabilities should serve this purpose. In this case, only L3 capabilities are deployed between central nodes on the backhaul network during the initial stage of LTE deployment.

An FMC bearer network

An FMC bearer network usually carries traditional fixed broadband services such as high speed Internet (HSI), VoIP, IPTV, and enterprise private line services, as well as GSM, 3G, and LTE services. The HSI service is connected to the network via DSLAM and then aggregated to the broadband remote access server (BRAS). This type network also adopts the hub-and-spoke traffic model. The VoIP service is generally carried over VPN, which helps to facilitate service deployment and management; it is also able to isolate VoIP service from other services more securely. The enterprise private line service is usually delivered over the L2 VPN or L3 VPN.

The number of fixed broadband access points is far smaller than that of base stations, but the fixed broadband access points have to handle much heavier traffic than base stations. Internet access and IPTV services account for most of the fixed-bandwidth traffic, while VoIP and enterprise private line traffic accounts for only a small percentage. Hence, network-wide L3 capability necessitates the use of a large number of provider nodes, which in turn may result in higher costs and make service management more complicated, thereby placing an even heavier burden when L3 extends to base stations. Therefore, the ideal traffic model should limit the use of L3 capability to the convergence layer that houses a small number of nodes, while deploying L2.5 capability in other parts of the network.

In summary, since the MPLS-based L2.5 bearer solution is easily manageable, it is suitable for use in traffic models at the 2G, 3G, and HSPA base station access. The L3 model can be used in instances where the LTE and FMC make the traffic

41

much higher bandwidth utilization and maintainability than the L3 solution that supports dynamic forwarding.

Backhaul for LTE

The traffic model designed for an LTE system is generally more complex in nature than the traffic model used for a GSM or 3G system. In an LTE system, the mobility management entity (MME) and the system architecture evolution (SAE) gateway communicate with the eNB by way of an S1 interface. For traffic transport, the S1 interface employs the hub-and-spoke model, which is similar to the traffic model of Iub interface in a 3G system. An X2 interface is used between eNBs in the LTE system to ease the SAE gateway traffic load caused by frequent handover. However, using this type of interface greatly increases the complexity of the traffic model for backhaul networks, as shown in Fig. 1.

Theoretically, each eNB must have a direct physical or logical link with i t s n e i g h b o r i n g e N B s i n o rd e r t o support X2 interfaces, if connection-oriented technology is used. However, physical or logical links tend to multiply exponentially, thereby making this type of solution unaffordable in terms of cost and management. Since X2 interface capability i s an outg rowth o f connec t ion l e s s technology, this necessitates the use of L3 routing in the backhaul network.

Shou ld L3 rou t ing be dep loyed partially or across the entire network? In theory, network-wide L3 capability is more efficient since it is able to support IP forwarding by utilizing the shortest path. However, the result ing traff ic i s unpredictable , thus this tends to complicate such aspects as management and maintenance. Obviously, adopting this path runs counter to the traditional approach o f c a r r i e r - c l a s s ne twork management.

Moreover, the traffic generated by using X2 interfaces only accounts for a small fraction of the network-wide traffic, which is usually less than 5% during initial LTE deployment. This approach is obviously not very cost-efficient if we deploy L3 capability across the network

Hub-and-spoke is typically the RAN traffic model for a GSM system. When this model is used, the BTS will collect all the user traffic through its air interface and the traffic will then converge at the BSC through point-to-point links. The BTS communicates with the BSC via a TDM-based Abis interface. Generally speaking, each BSC will aggregate traffic from scores of BTSs. In addition, traffic on the Abis interface usually remains steady, so the total bandwidth for a single base station will tend to vary slowly, according to the changing traffic.

This clearly shows that the RAN traffic in a GSM system is based on a point-to-point traffic model and tends to run quite steadily. Thus, this likewise proves that a backhaul network built on TDM-based SDH technology is quite capable of satisfying 2G communication needs.

In the present 3G communication era, the RAN interface is based on packet capability, but the traffic model does not change. Traffic on each Node B must converge at a RNC, which will handle and forward the traffic to other parts of the system. The traffic model is the same for either an ATM-based or Ethernet-based Iub interface.

A typical 3G system, especial ly a HSPA system, is distinguishable by its enhanced data service capability. In a 3G system, data traffic changes more violently than voice traffic. As a result, traditional SDH technology fails to meet 3G service bearer requirements, largely because SDH transmission is not capable of supporting statistical multiplexing for bandwidth between base stations. Since statistical multiplexing helps to improve bandwidth utilization, backhaul networks usually turn to utilizing packet technology.

The MPLS-based label switch path (LSP) is especially tailored so it can be used with the star-structured 3G traffic model. Known as L2.5, this technology relies on protocols such as open shortest path first (OSPF), intermediate system to intermediate system (IS-IS), and label distribution protocol (LDP), to establish dynamic LSPs. The L2.5 solution is easy to implement and is similar to SDH in terms of its service configuration and management. The solution also delivers

Choosing the right technology for mobile backhaul evolution

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model more complicated for operators’ ne tworks , bu t h igh e f f i c i ency and manageability must be properly balanced.

Currently, the L2.5 technology, or the technology that combines L3 and 2.5 capabilities, has been widely recognized by many global mobile operators and has become the leading FMC bearer solution.

Impact of other factors

Service type

Service types tend to vary widely from one mobile operator to another. Currently, most of the leading mobile operators have both GSM and 3G networks . HSPA networks are also quite prevalent in more developed regions. However, in underdeveloped regions GSM networks that mostly deliver voice services tend to predominate, while 3G networks are still in a nascent state. Therefore, the use of a simple service model should be able to easily satisfy the needs of operators that deliver only GSM and 3G services.

L2.5 technology is really quite suitable since it results in lower network CAPEX

and OPEX. Even in the LTE stage , when X2 interface traffic is light, L2.5 technology will aid in converging all services to point of presence (POP) for exchange. This action also has very little impact on bandwidth utilization, so the solution still works quite well.

Mobile operators who provide services to a large number of fixed broadband access subscribers usually have constructed a metro Ethernet (ME) somewhere along the way. As 3G services continue to flourish, these operators are expecting that they will be able to deliver mobile and fixed broadband services over a unified bearer network as part of their FMC drive.

Built on low-end LAN switches, most of the earlier MEs are not capable of supporting FMC bearer because they fail to support network synchronization or even MPLS, and therefore have poor QoS capabilities as well. Instead, existing MEs must be renovated, and in some cases new FMC networks become necessary.

Given this situation, L3 routing is preferable for FMC bearer networks, which are required to handle heavy traffic created by individual broadband and enterprise VPN services at the convergence

Fig. 1 LTE UTRAN traffic model

eNB

S1

S1X2

X2 X2

S1

S1

eNB

eNB

MME/SAE Gateway MME/SAE Gateway

layer and DSLAM access layer. In contrast, L2.5 technology is better suited for base station access. Overall, the technology portfolio that combines both L3 and L2.5 capabilities is more widely used.

Impact of O&M capability

O&M capability is also an important factor that may affect operators’ choice of technology. Currently, GSM networks deliver services over an SDH network. Accordingly, operators usually have a large department specifically set aside for SDH O&M. Therefore, existing SDH O&M staff can easily manage the IP backhaul network if it supports the same or similar management model as the SDH network. This usually reduces the OPEX significantly.

Deploying L3 capability across the network only to deliver a small number of simple IP services will result in a considerable increase in terms of costs, largely because this generally requires training the exist ing O&M team or recruiting an entirely new IP maintenance staff.

Network-wide L2.5 capabi l i ty i s preferred for operators who only deliver a small quantity of IP services. These particular operators should deploy L3 equipment on only a small number of nodes, while building L2.5 capability into other parts of the network even when flexible IP traffic is heavy. Adopting this approach will help to reduce OPEX substantially, though a small part of bandwidth is lost.

As for integrated service operators who have constructed MEs, using L3 routing will really not help to lower maintenance costs to any considerable degree. This is because they usually have a large IP O&M staff on hand to operate and maintain a considerable number of routers and Ethernet devices on their current networks. Therefore, it is recommended that these particular operators deploy L3 capability at the convergence layer and L2.5 capability at the base station access layer, largely because the L2.5 solution is much cheaper and more manageable than the L3 solution.

Editor: Liu Zhonglin [email protected]

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Latest developments of PTN standards

Find out more about the latest developments in the two standards of packet transport network (PTN) technologies: T-MPLS/MPLS-TP and PBB-TE.

Latest developments of PTN standards

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to function properly even in the absence of a control plane. The control plane is optional and generalized MPLS (GMPLS) is adopted. A T-MPLS network can be completely operated in the absence of any control plane protocols for dynamic configuration.

The IETF has also defined a series of capabi l i t ie s such as MPLS ping, bidirectional forwarding detection (BFD), and fast reroute (FRR). However, these OAM and protection capabilities either are IP-dependent or provide limited functionality and fall behind transport network requirements.

In 2007, the IETF organized the MPLS interoperability design (MEAD) team to research the differences between T-MPLS and MPLS technologies. The ITU-T

Latest developments of PTN standards By Zhang Haiyan

he transport of packet services like Ethernet, Voice over IP (VoIP), virtual private network (VPN), IPTV services and

the mobile backhaul of data services have created new requirements and challenges for the transport network. The PTN is increasingly becoming an industry trend. As a result, hopes are being raised that the PTN not only supports effective transport of packet services but inherits high reliability and simplicity in operation, administration and maintenance (OAM) from traditional transport networks, such as SONET and SDH networks.

Currently, two technologies are available for packet transport networks: Provider Backbone Bridge Traffic Engineering (PBB-TE), drafted mainly by the IEEE,

and MPLS-based Transport Multiprotocol Label Switching / Multiprotocol Label Switching Transport Profile (T-MPLS/MPLS-TP), which is jointly developed by the ITU-T and IETF. The following sections outline the latest developments of these two PTN technologies.

T-MPLS/MPLS-TPFirst proposed by the ITU-T, T-MPLS

is designed to support packet transport using the MPLS technology. T-MPLS and MPLS are based on the same forwarding mechanism, but T-MPLS has simplified the transport-independent L3 technology used in the MPLS and enhanced the OAM as well as protection capabilities. The T-MPLS technology isolates the data plane from the control plane and supports static configuration, enabling networks

formed a special team (T-MPLS Ad Hoc Group) to formulate T-MPLS standards. The two teams, which belong to different standardization organizations, merged into Joint Working Team (JWT) to jointly develop T-MPLS/MPLS-TP standards. T-MPLS was later renamed MPLS-TP.

Developments

In May 2005, ITU-T initiated efforts to formulate T-MPLS standards. By December 2008, the organization had released a range of standards regarding T-MPLS architecture, linear protection, equipment, interface, and management. Standards relating to T-MPLS OAM have given rise to much controversy. So far, only T-MPLS OAM requirements, known as ITU-T Y.Sup4, have been published, while the standardization procedure for T-MPLS OAM capability is suspended.

T

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Since 2006, router manufacturers have entered the T-MPLS architecture discussion. Later, IETF experts began to participate in developing T-MPLS standards. The T-MPLS OAM capability has become a focal point and a heated debate has occurred over labe l and Ethernet types.

At the meeting regarding ITU-T SG15 Q12 in September 2007, IETF and ITU-T experts made two recommendations for the T-MPLS standard.

One, ITU-T and IETF should team up to develop T-MPLS standards. Second, ITU-T should develop T-MPLS standard independently, but use Ethernet types different from those used by MPLS, rename the standard to differentiate from IETF MPLS and ensure that MPLS and T-MPLS do not overlap.

The ITU-T SG15 Q12 adopted the first recommendation. Later, ITU-T SG15 Q9 and Q11 and SG13 Q5 also adopted the first recommendation.

Afterwards, JWT began to coordinate M P L S - T P s t a n d a rd i z a t i o n w o r k . JWT’s area of responsibility includes forwarding, OAM, protection, control and management.

At the 73rd meeting in July 2008, the IETF presented 10 personal drafts relating to MPLS-TP, which cover MPLS-TP requirements and framework.

At the 74th IETF meeting, 4 of the 10 MPLS-TP drafts were adapted as WG (Work Group) drafts.

In December 2008, the ITU-T SG15 plenary meeting reviewed the four WG drafts.

In February 2009, the first MPLS-TP RFC (RFC5317) was released.

The JWT plans to complete LC (Last Call) on all drafts relating to MPLS-TP

requirements and framework by the end of Q2 2009. In May 2009, working teams relating to ITU-TSG15 and T-MPLS will start to

revise existing T-MPLS standards.

Currently, the first MPLS-TP-related IETF RFC, namely RFC5317, has been finalized. The draft is derived from the JWT report regarding

the use of MPLS in a transport network, which was presented in April 2008. Four IETF WG drafts have been formed to cover MPLS-TP requirements and architecture. A number of personal drafts relating to OAM, protection, control plane, management and interworking have been submitted. Judging from the current status of MPLS-TP standard development, d ra f t s regard ing requ i rement s and architecture have been rapidly progressing, but those relating to OAM, protection and auxiliary capabilities are still in the initial stage.

Key technical issues

The MPLS-TP standard has simplified the current MPLS technology and added a small number of capabilities. The standard integrates MPLS packet features into the O&M capability of a traditional transport network. This enables transport networks to support packet transport requirements in a simple but efficient manner. The MPLS-TP standard enables SONET/SDH networks to evolve towards packet transport networks.

Some of the key technical issues relating to MPLS-TP are:

Architecture: The MPLS-TP standard introduces the hierarchical concept from T-MPLS, which covers pseudo wire (PW), label switching path (LSP) and sections. The MPLS-TP capability must address compatibility and extension with the legacy MPLS and Pseudo Wire Emulation Edge-to-Edge (PWE3).

Service bearer/isolation: Similar to MPLS, the MPLS-TP standard can use the PW technology to carry multiple services. Additionally, interworking between MPLS-TP and MPLS has become a hot topic that can be approached in three ways: MPLS bottom stack label (S bit), PW encapsulation and special labels. Presently, it remains unclear which is the best choice.

OAM: OAM represents the core issue relating to MPLS-TP and radically drives the T-MPLS standard to change. OAM requirements have been determined, while the MPLS-TP OAM packet header format and OAM framework have also been roughly established.

The MPLS-TP standard integrates MPLS packet features into the O&M capability of a traditional transport network. This enables transport networks to support packet transport requirements in a simple but efficient manner.

Latest developments of PTN standards

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Protection: This is a key but controversial issue relating to MPLS-TP, especially when it comes to requirements for MPLS-TP ring protection. Fortunately, at the ITU-T SG15 plenary meeting in December 2008, MPLS-TP ring protection requirements were determined and written into the MPLS-TP requirement draft. It is uncertain whether to provide protection through FRR, ring sharing or otherwise.

Interworking: Scenarios where the interworking of MPLS-TP and MPLS applies need be clarified, including the forwarding plane and control plane. Interworking capability makes little sense before interworking scenarios are defined.

Control: MPLS-TP supports static configuration and should be able to function properly even without a control plane. The MPLS-TP standard can provide the ability to establish LSPs through RSVP-TE and set up PWs through the label distribution protocol (LDP) if a control plane is integrated into the standard. Moreover, the control plane may be extended for OAM and protection capabilities.

PBB-TE

Previously referred to as provider backbone transport (PBT) and first proposed by BT and Nortel, PBB-TE describes a connection-oriented Ethernet architecture, which is designed to provide a leading networking solution for BT’s 21CN program. At the IEEE meeting in Dallas, Texas in November 2006, Nortel presented a PBT project application, which was approved at the meeting. The PBT project was renamed PBB-TE for compliance with trademark rules.

Developments

The application for initiation of the PBB-TE standard 802.1Qay was approved in May 2007. The standard has evolved rapidly ever since. Currently, a vote being taken on 802.1Qay D5.1 is in progress. So far, key technical issues relating to the standard have been largely finalized and the standard is expected to be released in 2009.

Key technical issues

The 802.1Qay standard covers PBB-TE in service instance definitions, data forwarding, OAM, and protection.

Architecture: Connectionless Ethernet i s transformed into connection-oriented Ethernet by preventing the data plane from flooding, the control

plane from spanning tree and self learning and enabling forwarding table configuration through the management plane. Currently, the 802.1Qay standard limits the use of PBB-TE to single-domain scenarios.

Forwarding: The <DA, SA, VID> triplet is used to create PBB-TE service instances. Edge nodes will differentiate services according to the triplet, while middle nodes will forward packets according to <DA, VID> to adapt to traditional Ethernet devices.

OAM: The IEEE 802.1ag-based Ethernet OAM is extended to include continuity check (CC), loopback (LB), and linktrace (LT) capabilities which adapt to PBB-TE networks.

Protection: The standard defines a protection mechanism to satisfy the fast switching requirements. It replaces the ITU-T’s APS mechanism with the simply-defined remote defect indication (RDI) mechanism. The 802.1Qay standard only defines 1:1 and 1:1 load sharing protection modes and supports a number of manual switching commands. The IEEE is planning to set section-based protection standards in 2009.

Control: While the IEEE defines 802.1Qay data plane operations, related standardization organizations are setting standards in terms of PBB-TE control. The IETF Common Control and Measurement Plane (CCAMP) team has presented a WG draft relating to GMPLS controls PBB-TE. In addition, the provider link state bridging (PLSB) in 802.1aq, a standard under IEEE 802.1, can also be used for PBB-TE control.

T-MPLS/MPLS-TP vs. PBB-TE

Based on MPLS and Ethernet technologies respectively, T-MPLS/MPLS-TP and PBB-TE are designed to provide connection-oriented packet transport network through current packet technologies. Technically, both standards aim to detach the forwarding plane from the control plane, and enhance the OAM and protection capabilities so as to deliver high reliability and simplicity in OAM. In regards to future applications, the technology selection will depend on commercial considerations.

MPLS-TP standardization is in the pipeline and drawing a lot of attention from numerous telecom operators and equipment providers. Related architecture and requirements will become available during Q2 2009. In contrast, the PBB-TE standard is quietly evolving, receiving very little attention and related standards are expected to be released in 2009.

Editor: Liu Zhonglin [email protected]

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Paving the way for IP backhaul

urrent backhaul networks must efficiently transport existing networks’ E1 services, HSPA-based broadband services ,

and dynamic Ethernet packet services. IP microwave technology has emerged to fulfill these needs.

IP microwave incorporates adaptive modulation (AM) to directly map packet signals onto an air interface. Microwave

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When microwave meets the IP wave

When microwave meets the IP waveThe popularity of 3G networks has culminated in increased demands for IP and broadband services across mobile networks. However, this causes bottlenecks in conventional microwave systems. Existing bandwidth fails to meet service development and is unable to support Ethernet packet services.

By Li Jiangling

systems are in development that can transmit IP services and large service volumes to transport networks, but they require cutting-edge IP microwave technologies.

The All-IP oriented IP microwave system adopts packet switching as its core technology under which the air interface fully adopts packet technology. AM greatly improves the efficiency and capacity of packet data transmission by offering high bandwidth and dynamically adapting the packet microwave to different weather conditions, such as rain and fog. Technologies such as AM, layered QoS,

and high frequency modulation (256QAM) achieve this without interrupting existing TDM/ATM service transmission.

Benefits of packet microwave

Operators can utilize advanced packet microwave technologies to enhance mobile broadband service transmission in a number of ways.

Improving bandwidth utilization

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When networks evolve from SDH to IP-based backhaul, factors such as traffic connection and synchronization must be considered; otherwise, expensive GPS modules are required for multicast broadcast multimedia services (MBMSs) including mobile TV in LTE TDD and LTE FDD. In some indoor cases, it’s impossible to get GPS resource because antenna installation is not viable.

Current packet-based clock transfer technology is already advanced and can be applied to the IP-based microwave transmission system. Coupled with a PTN, this supports various packet-based clock transfer protocols including synchronous Ethernet and IEEE 1588v2, to realize network-wide E2E transmission and synchronization.

Smooth evolution

Huawei has innovatively integrated the TDM, hybrid, and packet microwave systems into a single system that smoothly transits conventional microwave to packet microwave. Huawei is also the only vendor offering the capability to provide seamless evolution from TDM, hybrid to pure packet microwave.

Hybrid microwave for 2G/3G

Given that TDM/ATM services and Ethernet packet services will coexist over the long-term, hybrid microwave transport forms an effective choice for operators as the air interface can encapsulate TDM and packet services into a unified microwave frame prior to transmission. The hybrid microwave supports three types of air interface modes: TDM, hybrid (TDM + packet), and packet.

The Huawei hybrid microwave features high bandwidth, optimum performance, and adaptive modulation to enable operators’ existing networks to develop into hybrid packet microwave transport networks and ease network transition pressures.

During the initial phase of evolving 2G networks to 3G, voice services still dominate mobile service provision and data services are negligible. In order to safeguard existing equipment investment and ensure existing voice service transmission, the

preferred solution during mobile transport network transformation should incorporate packet switching capability into existing TDM microwave equipment. After data services emerge as the major concern of mobile transport networks and all interfaces are technologically IP-based, the hybrid microwave system can completely function as a packet microwave system. This maximally extends system life cycle and decreases CAPEX.

All-IP of mobile broadband services will catalyze a massive increase in data services. This tends to promote an IP core as the mainstream choice, underpinned by an effective OAM mechanism from the IP Core to the IP RAN. The hybrid mode will gradually fail to meet holistic IP mobile network maintenance, encouraging the hybrid mode to smoothly evolve to an all packet mode.

Packet microwave for 3G/LTE The packet microwave mode converts

services from TDM to circuit emulation services (CESs) that are then mapped onto the microwave frame. The synchronous clock transfer specific to the Huawei packet mode supports synchronous Ethernet and IEEE 1588v2. Clock frequency accuracy exceeds +/-0.05ppm and phase synchronization occurs in under 1ms to meet the requirements of various radio mobile bearer networks.

The microwave transport network has developed from TDM microwave to hybrid microwave; this will inevitably evolve into a packet microwave network and become the preferred microwave transport solution for operators. Packet microwave networks yield the best performance/cost ratio, safeguard existing network investment, support flexible upgrades, and ensure compatibility.

Packet microwave equipment represents the optimal choice for future All-IP service transmission should operators choose to construct their own IP transport networks. As the only vendor able to provide TDM microwave equipment, hybrid microwave equipment , and packet microwave equipment, Huawei is positioned to assist operators construct a cost-effective microwave transport network capable of sustaining commercial growth.

Editor: Michael [email protected]

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The IP microwave system not only improves the bandwidth multiplexing and transport efficiency, but also supports burst service transmission via a packet switching kernel, a packet air interface, and statistical multiplexing technology. It optimizes the microwave frame structure and link protocol in a way that reduces OPEX and handles larger traffic volumes despite the limited bandwidth of microwave air interfaces.

AM lowers TCO

Compared with identical transport conditions in a traditional TDM microwave system, the IP system maximizes different services’ availability allocation ratio through AM by expanding transport bandwidth. AM adjusts transport bandwidth for low priority Ethernet packet services and maintains bandwidth for high priority E1 voice services.

The IP microwave system automatically changes modulation mode (for example, from 256QAM to 16QAM) in unfavorable weather conditions to ensure error-free bit communications. Microwave air interface bandwidth decreases to protect high priority services, while blocking low priority services. Favorable weather conditions stimulate a recovery in transport link quality and the system automatically resumes its original bit rate to transmit all services. Thus, AM technology implements condition-based bandwidth adjustments across the microwave air interface to help operators decrease frequency spectrum costs and reduce antenna weight, both of which lessen TCO.

Unified multi-service transport

Conventional 2G networks are based on TDM, 3G R99/R4, and now ATM. 3G R5/R6/LTE/WiMAX networks are transiting to IP-based networking, under which TDM, ATM, Ethernet, and other services can coexist in the long term. The IP microwave system carries existing services and realizes unified service transmission through E2E hybrid technology or pseudo wire emulation edge to edge (PWE3) to decrease equipment investment and O&M costs and complexity.

Packet-based clock synchronization

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Full scenario

PWE3/MPLS: 2G, 3G, and LTE coexistence

ver 90% of wireless sites will be reused during the 2G/3G transition to LTE. However, transit ion does not mean

“replacement”, and the three technologies will coexist over the long term. This situation will force transport networks to adapt to the varied requirements that arise in the different stages of wireless technology evolution.

The cost of wireless sites, including equipment room construction and rent, accounts for almost half of total wireless network CAPEX, while wireless base stations and the transport network incur 40% and 10% respectively. Comparing with the heavy cost of renovating their exist ing 2G/3G base stat ions, most operators choose to offer multi-service capabil it ies on their newly-built IP transport networks.

On ly MSTP and PWE3/MPLS-based packet transport technologies can currently carry TDM, ATM, and Ethernet services. As transport networks evolve toward IP te lephony, PWE3/MPLS technologies have emerged as a vital feature of the mobile bearer area.

IEEE 1588v2: low cost synchronization and full coverage

GPS or IEEE 1588v2 achieves the time synchronization that TD-SCDMA, CDMA, WiMAX, and LTE (including LTE TDD and LTE FDD) all require.

LTE requirements for bearer networksAs increasing numbers of leading operators unveil their LTE plans, the high requirements for LTE are shaping the development of bearer network technology. Notably, bearer networks must consistently deliver a carrier-class performance that caters to all scenarios and is underpinned by simplified and cost-effective O&M.

By Du Wei

LTE requirements for bearer networks

O

Frequency limitations mean that LTE provides less coverage than 2G and 3G; CAPEX is increased due to the necessary increase in base stations and the provision of network-wide GSP. However, IEEE 1588v2 technology reduces GPS costs and fortifies the telecom infrastructure by maintaining synchronization should GPS fail.

Wireless broadband is widely used in indoor applications. As GPS cannot penetrate roofs, time information from indoor base stations must be synchronized by the transport network, in which case GPON, Ethernet and others need to integrate IEEE 1588v2 capabilities.

OTN/WDM: high speeds and low OPEX

The current mainstream solutions for LTE-based high-speed railway applications prov ide network coverage through distributed BTSs, with multiple remote radio units (RRUs) located in the same cell. This solution reduces the number of cell handovers across base band units (BBUs) by enabling handover to occur within a single BBU. Doing so significantly enhances the broadband service experience as call drop rates are reduced during high-speed motion.

As the bandwidth of common public radio interface (CPRI) between a BBU and an RRU can reach 1Gbps and as base stations located on a rail system complicate maintenance and are prone to theft, compact optical transport network (OTN) and wavelength division multiplexing (WDM) devices are favored for the CPRI bearer. This solution lowers overall maintenance costs by reducing fibers, centralizing BBU management, deploying remote and

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distributed RRUs, and easing equipment room acquisition. Moreover, it is advisable to protect investment by deploying an IP bearer network that can evolve to incorporate OTN and WDM capabilities.

Carrier-class performance

LTE bearer: a connection-oriented entity

An LTE bearer network provides two interfaces: S1 to connect a base station to the core network gateway and X2 to realize logical inter-base station connections.

The S1 interface is topologically similar to the 2G Abis and 3G Iub interfaces and requires Flex capability for disaster recovery. Similar requirements would apply to the Abis and Iub interfaces as 2G and 3G networks become IP compatible, but this has not been realized yet. Protection extends beyond technology to involve a number of factors such as network topology, transmission directions, network construction costs, and requirements. The service gateway (SGW) only necessitates dual-homing protection, given that SGW would be relocated in the radio network controller (RNC) room. The network core must provide Flex protection as the mobility management entity (MME) is located in the central equipment room.

As LTE networks are designed to serve the general public, the X2 interface is obligated to comply with a given nation’s rules and policies, including requirements for legal monitoring. All traffic must be monitored through the gateway to prevent mobile subscribers from accessing each other without authorization. Operators currently only use the X2 interface to enhance adjacent base station handover, after which services st i l l need to be transmitted through the S1 interface.

As handover is confined to neighboring base stations, leading operators require the X2 interface to logically connect adjacent base stations so as to prevent the failure of a single base station extending to others by blocking full-mesh connectivity.

Connections in this way can only be established through static configuration due to complex coverage between base

stations. Creating a suitably connective link is unfeasible given the high requirements of the X2 and S1 interfaces for low delays coupled with strong protection capabilities. The connections, protection mechanism, and QoS features of the two interfaces must be pre-configured before services are launched over the LTE bearer network. This type of connection is immune from both aging and automatic changes, which in turn positions the LTE bearer network as essentially a connection-oriented entity.

Lower delay guarantees service experience

LTE is designed to enable the same capabilities as fixed broadband. Traditional 3G/HSDPA architecture handles services over four layers from subscription to service, causing lengthy delays and high costs. LTE’s flat structure considerably reduces delay to markedly improve the performance of broadband services.

LTE bearer networks require much lower delays than legacy fixed broadband bearer networks to achieve the same end to end (E2E) performance indices. However, the coding of wireless air interfaces creates long transmission delays, which lowers system throughout and potentially erodes the spectrum efficiency of wireless air interface. In this scenario, greater number of wireless carriers increases costs to guarantee sufficient coverage. Consequently, transmission delays must be minimized to achieve viable costs.

Tradi t ional switches and routers generate discrete transmission delays, which occasionally causes interruptions exceeding 1ms in single sites. As signal transmission generally passes through 10 to 20 sites, LTE bearer networks are unable to guarantee stable E2E transmission with low delays. As a result, operators opt for packet transmission equipment with fixed-length packet forwarding to deliver LTE bearer capability. For lower E2E delays, L3 handling procedures and the number of hops must be minimized.

H-QoS ensures base stations are always online

The LTE wireless layer realizes E2E

serv ice QoS control by control l ing signals and reserving resources. However, increasingly IP-based bearer network architecture stimulates a number of problems that degrade QoS across the LTE service layer, including network congest ion, packet loss , j i t ter, and delays. Since All-IP bearer networks may suffer from congestion, a mechanism for guaranteeing QoS under congested conditions must be implemented.

The QoS mechanism for the LTE base station transport network must meet two key requirements: first, prioritized service forwarding that mirrors traditional differentiated services; second, service guarantees at crucial base stations, for example, those at government buildings, hospitals, and schools, to ensure seamless service provision in the event of major congestion or a disaster. This requires hierarchical QoS (H-QoS) processing on the bearer network to schedule queues across different base stations and services to maintain the functionality of priority base stations and vital services.

Easy maintenance

LTE transport focuses on S1 not X2

LTE’s new logical inter face X2 is intended for handover. The interface features a complicated logical mesh connection that challenges legacy point-to-point transmission network architecture. Further analysis reveals that the X2 interface needs little bandwidth–a maximum of 3% of the amount required by the S1 interface. The E2E transmission delays must range from 50 to 100ms on the X2 service plane, 10 to 20ms on the signaling plane, but considerably under 5ms on the S1 user plane.

The time delay on the X2 interface has to adapt to mobility requirements while delays on the S1 interface must meet service and throughput requirements. The X2 time delay requirement is negligible if the bearer network accommodates the S1 interface delay requirement. Thus, X2 logical handover can also be performed on the bearer network or access gateway (AGW) convergence point. Notably, the

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bearer network is required to support X2 logical interconnection, which may increase demands on maintenance and equipment functions, such as L3 VPN.

In addition, preventing unauthorized connections between adjacent base stations requires a security control policy, though this can increase the bearer network CAPEX by over 30%. Is it worthwhile to increase investment by 30% simply to cover 3% of the traffic but degrade the QoS and maintenance for 97% of S1 services?

The exper ience of f ixed network operators shows that VPN PE routers can be located in the core metro equipment room to support low-traffic L3 VPN services over the broadband network. In terms of configuration and management, this model accommodates requirements that are similar to those of the X2 bearer and fixed network L3 VPN: low traffic, conf igura t ion needs , and f requent adjustments. Centrally configured VPN provider edge (PE) routers can represent the optimal X2 bearer solution if the time delay index is achieved.

Unified management ensures smooth evolution

LTE services are currently transported in two ways. The first reflects concerns regarding new technology by delivering 2G and 3G services over MSTP, and LTE services through a separate PTN. The second method aims to protect future investment by transmitting both 3G and LTE services over a PTN and migrating

existing 2G services from the MSTP to the network.

Both solutions must address the small size of base station rooms. As transport equipment is located in the base station cabinet, which provides 2U-3U space. However, the base station can smoothly evolve from 3G to LTE, with 2G and 3G coexistence occurring over the long term. Therefore, each solution has to provide unified end access through an equipment box.

Traditionally, one MSTP maintenance team is sufficient for wireless network maintenance. A specialized maintenance team is usually necessary for wireless and transport networks as the former requires operators to frequently adjust bandwidth, add carriers, and relocate sites. Otherwise, cross-departmental communication will increase maintenance cost and weaken troubleshooting efficiency. Thus, the unified maintenance and management of LTE and 2G/3G backhaul networks is vital for a smooth evolution process.

IP NMS visualization reduces OPEX

LTE deployment on a massive scale is inhibited by the challenge of rising OPEX. The Organisation for Economic Co-operation and Development’s (OECD’s) analysis of wireless broadband reveals that initial wireless broadband construction accounts for the bulk of expenditure, but that OPEX burdens operators during the latter stages. See Fig.1.

Therefore, the bearer network must

prioritize easy maintenance and availability. This promotes the advantages of legacy SDH networks, which operators can refer to as models of reliability and maintainability.

Legacy SDH networks provide a rich set of alarm and performance monitoring capabilities based on hierarchical overheads and ma in t enance in fo rmat ion . To support visualized E2E IP-based network management system (NMS) configuration a n d r a p i d t r o u b l e s h o o t i n g , P T N equipment must also provide hierarchical OAM capabilities in the same way as SDH equipment, and send comprehensive maintenance information to the NMS.

Compared with traditional IP equipment that supports single-site command line configurations, the visualized IP-based NMS increases configuration efficiency by 95%. Moreover, the system greatly improves fault detection efficiency, which eases maintenance complexity, and may significantly curtail OPEX in the context of massive-scale deployment.

A c u s t o m e r - f o c u s e d , e x p e d i e n t approach underpins the robust and sus ta inab le deve lopment o f beare r networks. With a focus on key mobile b e a r e r r e q u i r e m e n t s , Hu a we i h a s launched its multi-service platform based on PTN products. Geared to mobile operators’ broadband and All-IP transition requirements, the platform currently serves the world’s top 10 global operators, including China Mobile, Vodafone, Orange, and Telefonica O2.

Based on a unified platform, Huawei’s IPTime solution (IP infrastructure for Multi-Play experience) significantly simplifies maintenance by facilitating access via microwave, copper wire, and fiber lines. Huawei has incorporated E2E IEEE 1588v2 capability into its full product series, including PTN, GPON and routers . Oriented to operators’ k ey LTE bea re r r equ i r emen t s and incorporating hierarchical SDH network maintenance and management , the Huawei IPTime solution has considerably enhanced the PTN in terms of holistic adaptability, carrier-class performance, and maintainability. Thus, it can assist operators to provide 2G and 3G systems with full service LTE bearer capabilities.

LTE requirements for bearer networks

Editor: Pan Tao [email protected]. 1 OPEX reduction is key to LTE development

Accumulated cost of mobile broadband

Broadband early stage

(Source from OECD report)year

Billi

on E

UR

Broadband mature stage

OPEX

CAPEX

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