whitepaper017 reva celltowerbackhaul
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Aurora Networks, Inc.Aurora Networks, Inc.
July 2009
WHITE PAPER 17
2009 Aurora Networks, Inc. All rights reserved.
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2009 Aurora Networks, Inc. All rights reserved.2
Real at Last: Cable's Opportunity in Cell Tower Backhaul
Aurora Networks, Inc.
5400 Betsy Ross Drive
Santa Clara, CA 95054
Tel 408.235.7000Fax 408.845.9045
www.aurora.com
Copyright 2009 Aurora Networks, Inc. All rights reserved.
All rights reserved. No part of this document may be reproduced, stored in a retrieval
system, or transmitted in any form by any means, electronic, mechanical, photographic,
magnetic, or otherwise without the prior written permission of Aurora Networks.
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Real at Last: Cables Opportunity in Cell Tower Backhaul
Aurora Networks Provides Cable Operators the Technical Foundation
to Meet Wireless Industry Requirements
INTRODUCTION
After several years of rising expectations,
cable operators are finally in a strong
position to capitalize on what is shaping
up to be a far more explosive opportunity in mobile
backhaul services than many analysts anticipated.
While mobile backhaul has long been a discus-sion point in the outlook for cable commercial
services, several factors have served to delay a
full-scale push into this arena, notwithstanding
occasional cable operator successes at winning
backhaul contracts with mobile providers in various
localities. Most significantly, cables presumed
ability to leverage a ubiquitous fiber presence to
deliver backhaul services cost effectively has been
encumbered by the absence of cable-optimized
transport platforms that could meet the rigorous
performance requirements set by mobile
operators.
Cable operators could work around these
technical limitations by building dedicated
networks to support wireless backhaul service,
but they could not justify the aggressive market-
ing and service support initiatives that were
required to make this niche a high-priority targetsegment for their commercial services divisions.
Moreover, as long as the lions share of capacity
expansion requirements between cellular base
stations and base station controllers was tied to a
need for more T1 or E1 lines, the market demand,
while significant, was not factoring in a major need
for the Gigabit Ethernet-carrying capacity that
would play to cables fiber advantage over
competitors.
The good news for cable operators is that all these
barriers have fallen. The key technology issue has
been eliminated with the availability of equipment
supplied by Aurora Networks that meets or
surpasses mobile industry quality and reliability
standards across all performance metrics. Cable
operators can now use their fiber networks to
deliver carrier-grade Ethernet services that not
only provide the IP transport capacity required
by next-generation mobile networks; they can use
the superior Metropolitan Ethernet Forum (MEF)-
compliant circuit emulation capabilities made
possible through Aurora Networks technology
advances to support cost-effective expansion ofT1/E1 capacity over those Ethernet links as well.
Coinciding with this technology development,
demand forIP transport is taking off, fueled by a
sudden surge in consumer demand forIP-based
services over 3G networks and by an accelera-
tion in 4G infrastructure buildout schedules on the
part of mobile operators. Moreover, major cable
operators themselves have become part of this
4G acceleration, in some cases through partici-
pation in the Clearwire venture and in others by
virtue of acquisition of mobile spectrum on which
to launch LTE (Long Term Evolution)-based 4G
services. Taking steps essential to competing for
mobile backhaul services from current providers
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Real at Last: Cable's Opportunity in Cell Tower Backhaul
will position cable operators to compete success-
fully for backhaul business from their own mobile
units.
As a result of these developments the momenthas arrived for cable companies to move aggres-
sively to make delivery of mobile backhaul
services a core segment of their commercial
service operations. Targeting and winning
customers in this space will not only ensure cable
operators are positioned to benefit from the
coming explosion in wireless backhaul require-
ments; it will greatly enhance their ability to win
enterprise customers in the lucrative private lineservices market across all industry sectors.
THE FAST-CHANGING WIRELESSBACKHAUL SCENARIO
F
or some time research organizations have
been generating projections showing a
steep demand curve for wirelessbackhaul, based in part on escalating numbers of
cell tower base stations and in part on anticipated
increases in transport capacity over links connect-
ing those base stations to base station controllers.
For example, two years ago Infonetics Research
predicted global spending by mobile providers
on backhaul equipment and services would jump
from $20 billion in 2006 to $32 billion in 2009.
In another report on the cellular backhaul marketthe Heavy Reading research unit of publisher Light
Reading said the U.S. share of backhaul spending,
pegged at $2.8 billion in 2007, would jump to
$15 billion in 2011. Whereas the average number
ofT1/E1connections per base station was running
at 3 lines per site in 2007, Heavy Reading
predicted the average would hit 10 lines per site
in 2011.
Looking at the 2007-2009 timeframe, Infonetics
Research foresaw a near doubling of bandwidthrequirements per backhaul link, going from about
5 megabits per second to 9 megabits per second.
Infonetics projected that worldwide Ethernet
backhaul would grow to nearly 543,000 new
connections between 2007 and 2011, represent-
ing a 235 percent CAGR(cumulative annual
growth rate).
As aggressive as these projections were, the latest
developments involving accelerated rollouts of3G and 4G infrastructure together with
ongoing buildouts of 3G infrastructure suggest
backhaul capacity expansion will move at an even
faster pace. Even though just 11 percent of the
worlds cellular population has access to 3G,
carriers are already contracting forLTEinfrastruc-
ture, with major contracts now awarded in the
U.S., Japan, Sweden, Norway and Singapore,
according to research from In-Stat. And mobileWiMAX rollouts are underway or about to get
underway in several cities served by the partners
in the Clearwire venture. Both 4G platforms boast
peak downstream data rates in excess of 100
megabits per second.
Verizon Wireless says it will reach 20 to 30
markets with LTE-based services by the end of
2010. AT&T Mobile, with its own LTE deploy-
ments schedule to begin in 2011, recentlyannounced that, rather than waiting until then to
take the next leap in mobile bandwidth, it would
implement HSPA (High Speed Packet Access)
7.2 Mbps upgrades starting in the second half of
2009, thereby doubling its current peak rates over
the 3G HSPA network infrastructure. The
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company also announced it would nearly double
its 3G wireless spectrum in conjunction with
expanding 3G availability to another 20 metro
areas, bringing the total to nearly 370 cities byyears end.
These sudden leaps in mobile speeds are the
carriers market-driven responses to a much
greater consumer demand for Internet and multi-
media services than most observers anticipated.
The phenomenal success of Apples iPhone has
been accompanied by a surging demand for
applications from the Apple app store, with the
company reporting over one billion apps down-loaded worldwide within nine months of the stores
launch. Inspired by Apples success, various
handset makers and other players now offer an
aggregate of about 70 app stores around the
globe, according to the latest count from AT&T.
Other signs of surging demand for mobile access
capacity abound. U.K. researcher Ovum projects
that mobile broadband revenues, which topped
$30 billion in 2008, will jump to $137 billion by2014. Strategy Analytics forecasts there will be
an installed base of 100 million connected
consumer electronics devices beyond traditional
handsets by 2014, and another study from Rethink
Wireless forecasts operator revenues from such
non-handset devices will hit $90 billion in 2013.
Lending credibility to such projections, AT&T
Mobile has launched an emerging embedded
devices business unit with a mandate to build newecosystems and service models around mobile-
connected netbooks and MIDcomputers, e-read-
ers, automobiles and much else.
The impact of this surge in mobile bandwidth
consumption on backhaul requirements portends
to an even greater impact on backhaul capacity
requirements than researchers envisioned. Traffic
sampling undertaken by the Metropolitan Ethernet
Forum shows that in contrast to the 16 kilobits
per second of bandwidth required for the averagemobile voice call, Web browsing consumes at
minimum 128-384 Kbps per session and multi-
media streaming can consume anywhere from 2
to 15 Mbps.
Whereas Ethernet connections have accounted
for a very minor portion of wireless backhaul
capacity over the past few years, In-Stat predicts
the ramp-up in capacity requirements will result
in Ethernet links accounting for over half of allmobile backhaul capacity by the end of 2011.
Moreover, In-Stat notes, this shift to Ethernet is
not just for the purposes of accommodating the
surge in IP traffic; it is also a function of mobile
operators growing acceptance of the latest circuit
emulation capabilities over Ethernet as being
adequate to meeting the needs for more T1/E1
connections. As shall be seen, this has crucial
implications for cable operators who make useof the circuit emulation capabilities built into Aurora
Networks wireless backhaul solution.
KEYS TO CABLES SUCCESS INCOMPETING FOR WIRELESS
BACKHAUL BUSINESS
Clearly, the greater-than-expected near-
term leap in backhaul capacity needscreates a new measure of urgency
behind cables opportunity to play a significant
role in this market. In its 2007 report on wireless
backhaul trends and opportunities forMSOs,
Heavy Reading said, IfMSOs don't make cell
backhaul a top priority soon, they could find
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Real at Last: Cable's Opportunity in Cell Tower Backhaul
themselves limited to just a small slice of the market
if not shut out altogether. Given the pace at
which capacity demands are outstripping
projections from Heavy Reading and others, thestatement has more validity now than ever.
Needless to say, the surge in backhaul capacity
demand represents larger opportunities for all
suppliers of such services, not just cable. This
means cable operators must take advantage of
all the means at their disposal to deliver competi-
tively priced wireless backhaul services that meet
or exceed all the performance requirements set
by mobile carriers.Presently, according to New Paradigm Resources
Group, at least 85 percent of all U.S. cell sites
are served solely by local exchange carriers
copper plant. At the same time, according to
Insight Research, over 90 percent of U.S. wireless
backhaul traffic is served by leased private lines,
which means wireless carriers prefer to lease
capacity even though microwave options are
available that would allow them to own their ownbackhaul infrastructure. According to ABI
Research, the high costs of real estate for mounting
antennas combined with high per-megabit costs
of microwave technology will continue to be
barriers to wireless carriers use of this option,
especially in North America, even as high-speed
Ethernet connectivity becomes a major increment
of ongoing capacity requirements.
Thus, wireless carriers must either continue to relyon local exchange carriers as capacity needs
outstrip the usefulness ofT1/E1 connectivity or
find alternative providers who can meet the need
for both T1/E1 and high-speed IP transport
capacity cost effectively. While competition has
forced LECs to reduce T1 line rates, in some
cases into the $300-per-month range, telco prices
for fiber-based private line services have remained
high, with specific rates depending on transmis-
sion speed, a fixed rate for central office termina-tion and a mileage charge for the fiber transport
distance. These pricing trends have the effect of
driving demand for ever more T1 lines as long as
TDM-based transport is a viable option, while
leaving a cost chasm in instances where the high-
bit-rate requirements ofIPservices call for fiber-
based connectivity.
Mobile carriers can ill afford such increases in
backhaul expenses. Already, backhaul operationsaccount for up to 30 percent of mobile operators
total operations costs, according to Infonetics
Research.
Cables chief advantage in taking on the
entrenched dominance of the telcos as private line
service providers to the wireless backhaul market
rests on the proximity of cable fiber nodes to
mobile base stations, which means operators are
frequently in a position to extend fiber to basestations at far lower costs than can be achieved
by telco competitors. By several estimates, cable
fiber nodes are in close proximity to 70-80 percent
of the businesses in their markets, most of which
are situated in the commercially zoned locations
where base stations are most likely to be found.
Now cable operators finally have the technologi-
cal means to exploit this fiber advantage in the
wireless backhaul market. Thanks to theavailability of cable-optimized optical transport
technology from Aurora Networks as described
below, cable operators can employ Ethernet
transport across their existing fiber infrastructure
to provide a cost-competitive combination of
multiple T1/E1 links and multi-megabit Ethernet
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connectivity to accommodate both the voice and
IP-traffic demands of mobile carriers.
Mobile carriers who are faced with charges for
comparable services from LECs that can run tomany thousands of dollars per month per base
station will be able to obtain these services from
cable operators at much lower rates. Given this
cost advantage, cable operators are well
positioned to compete for wireless carrier
business, even in instances where the mobile
providers are units of the LECs. Bottom-line-
driven business practices that value cost savings
and migration flexibility over loyalty to any onesupplier will always prevail.
However, it is essential that cable operators enter
into competition for this business as full-service
private line market providers with the commit-
ment of technical staff, sales and customer service
personnel as well as marketing clout that conveys
a sense of dedication to the wireless segment.
Because the technical foundation enabling delivery
of private line backhaul services positions cableoperators to compete for private line business in
general, operators stand to gain not only new
revenues from other enterprise segments but also
greater credibility in the eyes of potential wireless
customers to the extent they are viewed as major
competitors for private line business in the
enterprise marketplace.
THE TECHNOLOGY FOUNDATION TOCABLES OPPORTUNITY IN WIRELESS
BACKHAUL
While there has been a long-held pre-
sumption that cable operators could
use existing fiber plant, including
HFC distribution fiber, to support wireless
backhaul services, the fact is that crucial technol-
ogy advancements were needed to ensure that
solutions supporting cables participation in this
market met all performance requirements. Aurora
Networks has met these requirements by
combining its Ethernet-over-cable transport know-how with Ethernet service capabilities that comply
with the rigorous standards set by the Metro
Ethernet Form and the mobile industry.
Most significantly, these include the T1/E1 circuit
emulation requirements embodied in the MEF-8
and MEF-18 specifications. To achieve MEF-18
certification Aurora Networks next-generation
TDM-over-packet GT3410A T1/E1 solution had
to pass a set of 334 stringent test cases that are
designed to ensure that a provider of Circuit Emu-
lation Services over Ethernet (CESoETH)
conforms to market requirements.
Aurora Networks is one of only three vendors
that have been certified to be compliant withMEF-
18 and theonlyone to date found to be compliant
forbothT1 and E1 circuit emulation. Aurora
Networks has also been certified on the key
Ethernet User Network Interface and Traffic
Management metrics contained in the MEF-9 and
MEF-14 specifications.
The benchmarks set by MEF-18 represent a
significant advance over the capabilities of various
pseudo-wire solutions that have been in the
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Real at Last: Cable's Opportunity in Cell Tower Backhaul
marketplace several years but which, in general,
have fallen short of the performance requirements
set by mobile carriers for backhaul applications.
TheMEF-18 tests provide assurance that the jitter,wander, frame loss and packet delay metrics on
a per-link and aggregate backhaul network basis
are well within tolerance levels set for all
generations of GSM, CDMA and WiMAX
networks.
Synchronization of clock timing, inherent to the
mechanisms in a T1 orE1 copper link, has been
one of the biggest hurdles for Ethernet circuit
emulation techniques when applied to mobilebackhaul. Each cell site must use a clock source
that is synchronized with the overall network clock
so as to produce minimum wander, which is a
measure of how far clocks move out of sync over
a given timeframe, and jitter or packet delay
variation, which measures the impact of timing on
a per-link, per-flow basis.
Given the fact that the typical local radio access
network backhaul infrastructure can consist of oneto two network controller sites serving anywhere
from hundreds to thousands of base stations,
maintaining clock synchronization across the entire
backhaul system is an especially daunting
challenge. According to the MEF, most mobile
networking applications require a frequency
accuracy of 50 parts per billion.
Packet-based synchronization operates indepen-
dently of the physical layer by applying sophisti-cated algorithms to reconstruct the time and
frequency information from the packet flow. To
be certified compliant with MEF-18, Auroras
GT3410A platform had to meet the stringent
standards set by the ITUs G.823 and G.824 jitter
and wander requirements.
The GT3410A achieves the required synchroni-
zation accuracy by applying Adaptive Clock
Recovery methods, where end points measure
the inter-arrival time of the received packets toreconstruct the original frequency information. All
elements across the TDM and packet network
are thus tightly synchronized to the primary clock
reference positioned at the cable headend or wire-
less base station controller. Critically, this in-band
clock synchronization approach eliminates the
need for additional synchronization equipment and
minimizes packet overhead related to timing, which
makes it more efficient and cost effective as
compared to alternative methods. This schema
is graphically depicted in Figure 1.
But accuracy through packet-based synchroni-
zation can only be maintained to the extent that
the system maintains rigorous Layer 2
performance levels with regard to packet
impairments such as end-to-end delay, delay
variations and frame loss. Auroras GT3410A
platform is designed to maintain sub-millisecondtransport delay over point-to-point links, thereby
ensuring packet-based synchronization meets the
rigorous requirements ofTDMclock synchroni-
zation.
This Layer 2 performance has important implica-
tions for circuit emulation over cellular backhaul
links, where the total end-to-end delay threshold
encompassing all system components cannot
exceed 8 milliseconds. Because the introductionof Aurora-based CESoETH technology
contributes just a sub-millisecond delay element,
the solution is eminently suited for use on legacy
CDMA T1/E1 cell site and controller interfaces.
Each GT3410Amodule has fourT1/E1 interfaces
and serves to aggregate that traffic into the one
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Gigabit Ethernet Fiber interface for transport over long
backhaul distances, thereby functioning as an inter-
networking agent between the T1/E1 and metro
Ethernet clouds in conformance with theMEFs Generic
Inter-working Function (GIWF). The GT3410A also
has one 10/100/1000 copper interface that can be
utilized for back-hauling high speed data traffic in the
vicinity of cell tower thus adding more flexibility to cable
operators solution portfolio.
By employing the GT3410A across all wireless
backhaul end points cable operators can provide a
solution that allows wireless carriers to support
and expand legacy PDH (Packet Digital
Hierarchy) T1/E1 connections while providing
them a one Gigabit Ethernet interface to accom-
modate IP traffic flows.
When installed in a 3RU CH3000 chassis (as
shown in Figure 2) for deployment at base station
controllers or the cable headend, multiple
GT3410A modules provides support for up to 80
T1ports in a single chassis. The GT3410Amodule
can also be installed as a single module in the 1RU
Figure 1. In-band Clock Synchronization Based on Adaptive Clock Recovery
Figure 2. GT3410A T1/E1 Access Modules Installed in the 1RU CH1301 CPE Chassis (at left)
and Pictured with the 3RU CH3000 Chassis (at right)
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Real at Last: Cable's Opportunity in Cell Tower Backhaul
CH1301 CPE chassis for placement at base
stations. Several such individual GT3410A units
(inCH1301Bchassis) can be daisy-chained together
to connect into the cable operators access fiberover separate CWDM wavelengths, thereby
allowing more efficient use of fiber at base station
sites with high densities ofT1/E1 ports.
A reference drawing for one possible architecture
is shown in Figure 3.
TheGT3410A is fully compatible with the cable
network-optimized Fast Ethernet and Gigabit
Ethernet capabilities widely used with Aurora
Networks solutions such as Fiber On Demandand its family ofSMART Media Converters.
These transport capabilities provide CWDM and
DWDM Ethernet conduits over the existing fiber
distribution and metro backbone plant, allowing
the operator to aggregate and terminate all base
station traffic on the CH3000 at the headend or atthe wireless operators base station controller.
This flexibility in Ethernet-over-cable architecture
gives operators the option to serve base station
controllers directly in regions where the cable
metro fiber plant is proximate to controllers or to
hand off aggregated base station traffic from the
headend to other providers of high-capacity links
between the headend and the controller site.
Operators, of course, can also terminate theEthernet traffic at the headend and build out their
own or lease TDM DS3 orOC-12 links to reach
the controller.
Figure 3. Reference Architecture
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CONCLUSION
The accelerated pace of 4G deployments
amid ongoing 3G expansion worldwide
is compounding an already difficult
backhaul capacity conundrum for mobile service
providers. Legacy backhaul infrastructure
suppliers with their dependence on TDM-based
connectivity over copper and their inflated pricing
for fiber access are not well positioned to serve
these expansion needs, especially if cable
operators can provide the wireless industry with
options that prevent backhaul costs from
becoming an even larger share of wireless carrieroperating budgets.
But wireless carriers cant be expected to wait
for these alternative solutions to emerge over time.
With researchers predicting the average number
ofT1/E1backhaul ports per base station will more
than double over the next two years as the need
for high-speed IP packet throughput jumps to a
significant share of overall backhaul capacity its
clear the wireless players will be locking down
on these next-gen needs very quickly.
Cable operators now have the means at their
disposal to address this market with an integrated
fiber-based solution that leverages existing
network resources to meet the full range of wire-
less backhaul requirements. Aurora Networks
MEF-18 certified GT3410A solution provides
wireless carriers the assurance they need to exploit
the tremendous cost savings made possible
through use of Ethernet-based circuit emulationto deliverTDM traffic over high-capacity Ethernet
fiber. Thus, by deploying the GT3410A platform
at base stations and base station controllers, cable
operators can take advantage of Aurora
Networks market-proven Ethernet-over-cable
transport capabilities to deliver both the T1/E1
and the pure Ethernet support wireless carriers
are looking for.
Moving in this direction to serve the private line
transport needs of the wireless industry also
positions cable operators to compete aggressively
for other segments of the private line business.
Cable operators ability to leverage their fiber in-
frastructure in conjunction with use of the Aurora
Networks GT3410A platform to aggregate PBX
voice traffic overT1 circuit emulation interfaces
with LAN traffic on the Ethernet interface gives
them entre to one of the hottest markets in
commercial services.
The magnitude and urgency of the wireless
backhaul market represents a huge opportunity
for cable operators to be players in a $40-billion
global market. There has seldom been so
promising a point of entry into a new market for
the cable industry.
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Real at Last: Cable's Opportunity in Cell Tower Backhaul
Aurora Networks, Inc.
5400 Betsy Ross Drive
Santa Clara, CA 95054
Tel 408.235.7000
Fax 408.845.9043
www.aurora.com