213_mlucchin_rev4.ppt

xDSL Technologie & Architectures

2© 1998, Cisco Systems, Inc.

213NW’98

213NW’98 3© 1998, Cisco Systems, Inc.

• BasicsBasics

• Applications

• Architecture

Agenda


The Flavors of DSL

• HDSL H = high data rate384KB–2MB, usually symmetric,one or two lines, 4-5Km

• SDSL S = single lineOffshoot of HDSL, up to 2 MB, symmetric, one pair, 3-4Km

• IDSL I = ISDNBasic rate ISDN service terminated on a dedicated device at the central office


The Flavors of DSL

• ADSL A = asymmetric

Up to 8 MB downstream and 640 KB upstream, one line, 6Km

• RADSL RA = rate-adaptive

Nuance of ADSL, data rate adapts to line conditions

• VDSL V = very high data rate

Up to 52 MB downstream, 2+ MB upstream; 1,5-2Km


Single Pair Telephone Line

xDSL Modem

xDSL Modem

Corporation or ISP

Central Office

Remote Location

Splitter

POTS

TelephoneSwitch

Generic xDSL Implementation

An Access Solution: Connects Remote User An Access Solution: Connects Remote User to Central Office as a Dedicated Circuitto Central Office as a Dedicated Circuit

An Access Solution: Connects Remote User An Access Solution: Connects Remote User to Central Office as a Dedicated Circuitto Central Office as a Dedicated Circuit

Data Network


Advantages Disadvantages• Proven technology • Two MB maximum data rate• Uses in-place copper loops • POTS requires second line• Reduces load on C.O. switch • Few vendor choices

HDSL/SDSL

Data Network

HDSL/SDSL Modems

MDF

<> 2 MB

HDSL/SDSL Modem


Advantages Disadvantages• Reduces load on C.O. switch • Limited data rate• Uses standard ISDN equipment • Second line for

POTS• Inexpensive to deploy

IDSL

Data Network

ISDN T/A

MDF

2B1Q


ADSL Terminology

• ATU-R: ADSL Transmission Unit, Remote

The remote user’s ADSL modemThe CPE

• ATU-C: ADSL Transmission Unit, Central

The ADSL point of termination in the central officeAn ADSL modem

• DSLAM: DSL Access Multiplexer

Central office device that concentrates many ADSL connections into oneDSLAM contains ATU-Cs


Advantages Disadvantages• Date rate • Expensive modems,

today• Uses in-place copper loops • Speed/distance trade-off• POTS on same line• Reduces load on C.O. switch• Emerging as the standard

8 Mbps >

< 640 Kbps

DSLAM(ATU-C)

VoiceNetwork

MDF

ADSL

Data Network

xDSL Modem

Splitter

Splitter


What It will Evolve to• Ethernet frames or cells to the desktop• 1483 or PPP over ATM• Cell, Frame Relay, or packet backhaul• Traffic shaping, per user• Layer 3 service in the C.O.

Connectivity, ADSL

Ethernet Frames

Ethernet Frames

CellsPacket

Frame Relay

VoiceNetwork


What Is xDSL?

New Transmission Techniques That Drive High Data Rates over a Telephone Line’s

Higher Frequencies, Often without Disrupting POTS

New Transmission Techniques That Drive High Data Rates over a Telephone Line’s

Higher Frequencies, Often without Disrupting POTS

0 Hz 4400 Hz 1 MHz

POTSPOTS ADSLADSL


CAP and DMT Spectrum

CAP RADSL Frequency Range DMT Frequency Range

0 KHz0 KHz0 KHz0 KHz 4 KHz4 KHz4 KHz4 KHz 30 KHz30 KHz30 KHz30 KHz 138 KHz138 KHz138 KHz138 KHz 156 KHz156 KHz156 KHz156 KHz 1 MHz1 MHz1 MHz1 MHz0 KHz0 KHz0 KHz0 KHz 4 KHz4 KHz4 KHz4 KHz 30 KHz30 KHz30 KHz30 KHz 138 KHz138 KHz138 KHz138 KHz 156 KHz156 KHz156 KHz156 KHz 1 MHz1 MHz1 MHz1 MHz

POTSPOTS DownlinkDownlinkUplinkUplink POTSPOTS DownlinkDownlinkUplinkUplink


ADSL Rates

DownstreamDownstream UpstreamUpstream

7 Mbps7 Mbps

2.5 Mbps2.5 Mbps

640 kbps640 kbps

1 Mbps1 Mbps

680 Kbps680 Kbps

950 Kbps950 Kbps

DownstreamDownstream UpstreamUpstream

8 Mbps8 Mbps

4 Mbps4 Mbps

2 Mbps2 Mbps

640 Kbps640 Kbps

64 Kbps64 Kbps

160 Kbps160 Kbps

ETSI Annex T1.413CAP RADSLSymmetric Rates Possible


xDSL Comparisons

Data RateDown/Up Links

Data RateDown/Up Links

VDSLVDSL

Distancekm

Distancekm

Modulation Scheme

Modulation Scheme

SDSLSDSL

HDSLHDSL

IDSLIDSL

ADSLADSL

25 Mbps/1.6Mbps25 Mbps/1.6Mbps .9.9

6.96.9

5.55.5

5.55.5

4.64.6

DMT/CAPDMT/CAP

QAMQAM

784kbp/1784Kbps784kbp/1784Kbps

144Kbps/144Kbps144Kbps/144Kbps

8 Mbps/1.Mbps8 Mbps/1.Mbps

1.5 Mbps/1.5Mbps1.5 Mbps/1.5Mbps

2B1Q2B1Q

2B1Q2B1Q

2B1Q2B1Q


Application Use

xDSLxDSL

Video, V.R., MultimediaVideo, V.R., MultimediaVDSLVDSL

Telecommuting, Remote Office ConnectivityTelecommuting, Remote Office ConnectivityIDSLIDSL

H/SDSLH/SDSL T1 Replacement, Remote Office ConnectivityT1 Replacement, Remote Office Connectivity

Telecommuting, Remote Office Connectivity, Intense Web AccessTelecommuting, Remote Office Connectivity, Intense Web Access

ADSLADSL

ApplicationApplication


Some Benefits of xDSL

• High bandwidth at low cost

• Load on C.O. switch is reduced

• Enables service providers to create new network services

• Facilitates new and better content delivery


Some Implications of xDSL

• Demands larger and more robust backbone data networks

• Deploying today may require use of immature technology

• Effective pricing and service models need to be defined


• Basics

• ApplicationsApplications

• Architecture

Agenda


xDSL Modem Technology

xDSL Modem TechnologyxDSL Modem Technology

Speed vsDistanceSpeed vsDistance

PortDensity

PortDensity

ModulationTechniqueModulationTechnique

POTS/ISDNSplitters

POTS/ISDNSplitters


Scaleable High Performance Infrastructure

High Performance InfrastructureHigh Performance Infrastructure


xDSL PoP

Caching Provisioning Core


Differentiated Service ElementsThe Enabling Technologies


Service ElementsService Elements


Layer 3Internet

Layer 2/3VPNs

Multicasting QoS



ServicesServices


Applications

ApplicationsApplications

High-SpeedInternet

High-SpeedInternet

DistanceLearningDistanceLearning

CorporateAccess

CorporateAccess

VoIPVoATMVoIP

VoATMEntertainmentEntertainment Financial

PushFinancial

Push


Service Selection Dynamic Selection Under User Control

High Performance Routing and SwitchingHigh Performance Routing and Switching

Service ElementsService Elements


ApplicationsApplications

High-SpeedInternet

High-SpeedInternet

DistanceLearningDistanceLearning

CorporateAccess

CorporateAccess VoiceVoice EntertainmentEntertainment

FinancialPush

FinancialPush

Service SelectionService Selection


Corporate Intranet Access

POTS/ISDNSplitter

POTS/ISDNSplitter

ATU-R/RouterATU-R/Router

VoIP/VoATMVoIP/

VoATM

ATU-RATU-R

RouterRouter

ADSL PoP

ADSLAM

Aggregator

Authentication

Sp

litter

Sp

litter


Distance Learning

Live or Stored Content Delivery to Remote Classrooms,Dormitories, Homes

ADSL PoP

ADSLAM

Aggregator

Education Network

ATM Core

Packet Core

Cache IP/TVS

plitte

rS

plitte

r


ADSL PoP

Aggregator

Authentication

High-Speed Internet Access

Hierarchy of Cache Engines

ADSLAM

Cache

ISP (a,b,c)

Sp

litter

Sp

litter


Entertainment

ATM CoreISP (a,b,c)

CNNHeadlines

CNNHeadlines

MyTVMyTV

SportsUpdateSportsUpdate

MyTVMyTV

CNBCReport on

CSCO

CNBCReport on

CSCOMyTVMyTV

WeatherWeather

MyTVMyTV

• 30–120 sec video clips cached, assembled, and pushed based on predefined or user-defined profile

• Non-interactive “personal” TV providing video and data clips

• Requires IP Multicast and QoS support Variation Is ‘True’

VoD in Some Niche Markets

Such as Hospitality, Medical, Education

ADSL PoP

ADSLAM

Aggregator

Cache VoD

Sp

litter

Sp

litter


POTS/ISDNSplitter

POTS/ISDNSplitter


VoIP/VoATMVoIP/

VoATM

ATU-RATU-R

RouterRouter

ADSL PoP

ADSLAM

Aggregator

Financial Data Distribution

Push

Relies on Publish-and-SubscribeInternet Push Technologies—TibcoNetwork Must Support IP Multicast

Stock Info

Stock Info

Stock Info

Stock Info

Stock Info

Sp

litter

Sp

litter


ADSL—Data Bypass

ADSL

L2/L3 Engine

ADSL

Central Office

SMB/SOHOSMB/SOHOCPE

Copper Loop

ContentProviders

POTSPOTSSplitterSplitter

ResidentialResidential

DSLAM

MD

FM

DF

POTSPOTSSplitterSplitter

Sp

litter

Sp

litter


POTS/ISDNSplitter

POTS/ISDNSplitter


VoIP/VoATMVoIP/

VoATM

ATU-RATU-R

RouterRouter

Voice

ATM Core

Packet Core

ISP (a,b,c)

CorporateGW (a,b,c)

ADSL PoP

ADSLAM Aggregator

POTS/ISDN

Interworking for PSTN Connectivity

Sp

litter

Sp

litter


End-to-End ADSL Architecture

ATU-RATU-R

ATU-RATU-R

IP

UCP UCP

Central Office

IPIP

Content ProvidersBroadband NetworkLocal Loop

PSTN

ISP

ISP

Corporate

DSLAMDSLAM

L2/L3 Services

Aggregator

L2/L3 Services

Aggregator

ATM/Frame Relay

Network


• Basics

• Applications

• ArchitectureArchitecture

Agenda


ADSL Based Architecture

SDH or ATMBackbone

SDH or ATMBackbone

IP Backbone

IP Backbone

Access NetworkAccess Network

• Service delivery network


VoiceFilter

Multiservice DSL Multiplexer

VoiceFilter

OC-3/STM-1

• Support many subscribersADSL CAP or DMT

Adaptive or selective

• Line rates

• ATM architecture

• OC-3/STM-1 trunk cards

• DS3/E3 trunk cards

• External voice filtering

• NEBS compliant

• WEB-SNMP managed


STM-1,E3 or

4xE1

Customer

Premise

ADSL

Loops

NxM

Switch

NxM

Switch

ADSL

360 56 56xDSL

Modem

Pool

xDSL

Modem

Pool

Off HookOff Hook

DetectDetect

&&

SwitchSwitch

ControllerController

360Line

Cards

Line

CardsMuxMux

• Optional modem pooling technology

• Enables subscriber concentration up to 10:1

• Lowers cost, power consumption, heat dissipation

• Logical pooling increases tariff flexibility

Digital Off-Hook


ATM

E3

ATM

STM-1, E3

ATM

E3

Subtending

• Subtend up to (6) 6200e chassis from a single 6200e

• Scales up to 2,800 users per ATM Network Connection

• Fewer ATM switch ports required

ATM

E3

Network Backbone

ATM

E3

ATM

E3ATM

E3


6200e System Components

MultiplexerMultiplexerChassis (MC)Chassis (MC)

Line ConcentrationLine ConcentrationChassis (LCC)Chassis (LCC)

POTS SplitterPOTS SplitterChassis (PSC)Chassis (PSC)


• 38 slots– Primary / Secondary System Controller Slots (11,27)

– Primary / Secondary Network Interface Slots (9,10), switch fabric

– 32 Universal Slots for ATU-Cs or LIMs (1-7,12-26,28-34), modem cards

– 2 Expansion Slots (8,26)

Multiplexer Chassis (MC)

1 2 3 4 5 6 7 8 9 1011

12131415161718

192021222324252627

28293031323334


1 2 3 4 5 6 7 8 9 1011

121314 1516 1718

19 20 21 2223 2425 2627

282930 3132 3334

Subtend Host Modules

Expansion SlotsExpansion Slots

• Use Expansion Slots to access ATM switch – 90 Mbps serial connection to its own ATM switch port

• Aggregates ATM connections from subtended 6200e’s


Line Concentration Chassis (LCC)

• Extends Line Capacity of MC through Digital Off-Hook

• Supports 18 quad port LIMs

• MC can electrically support up to 5 LCCs (360 lines maximum)

1 2 3 4 5 6 7 8 9

10 11

1213 1415 1617 18 19 20


POTS Splitter Chassis (PSC)

• Subscriber loops with POTS/RADSL terminate at PSC (18 lines per 50 pin CHAMP)

• Provides connections to Voice Switch and 6200e MC/LCC

• Supports 18 quad port PSMs

• Passive Chassis

1 2 3 4 5 6 7 8 9 10 11 12 1314 1516 1718 19 20 21 221 2 3 4 5 6 7 8 9 10 1112 1314 1516 17 18


POTS Splitter Modules

• 4 subscriber ports per PSM

• Separates Voice band frequencies from composite signal

• Active power options available

PSM SlotsPSM Slots1 2 3 4 5 6 7 8 9 10 1112 1314 1516 17 18


STM-1,E3

ATM

288 RADSLSubscriber Lines

Ethernet and SerialManagement

Interfaces

Data Interfaces

Class 5 Switch

ATM Network

6200e Physical Connections

LCCLCC

LCCLCC

LCCLCC

LCCLCC

PSCPSC

PSCPSC

PSCPSC

PSCPSC

MCMC

MDF

PSTN

72 ADSL Lines

72 POTS Lines

72 ADSLLines

80 POTSLines


Multiservice DSL Aggregator

• High-capacity

• NEBS and ETSI compliant

• Fully redundant

• Multi layer ATM-switch

• Optional plug-in routersto add L2/L3 services

• Multiple slots:

• SONET STS3/SDH STM1ATM OC-3 trunk

• DS3/E3 ATM, DS3/E3 FR

90i/s90i/s


ADSL CPE Requirements

• IP routing

• Multicast support

• Traffic shaping

• Network address translation

• Data and voice integration

• IP over ATM support

• Management


Design Considerations

• Twisted pair bundle issue

• Throughput expectations

• Traffic shaping and policing

• L3 Breakout at the edge

Scalability and value-add services

• Network/content designNetwork/content design


Multiservice DSL Architecture

• Optimized VC budget

• Dynamic assignment of IP addresses

• Service differentiation

• Dynamic service selection

• Provisioning flexibility

• Existing operational support


ADSL Design

• VC management

• Bandwidth management

Architecture: L2 vs. L3

Value add: Content management

• CPE requirements


A Multiservice DSL Solution

MultiserviceAccess

MultiserviceMultiplexing

MultiserviceCreation

MultiserviceCore

MultiserviceUniverse

A

B

C

D

A+D

D


ADSL Ethernet model

• Broadcast segmentation

• LAN switches

Port fanout

VLAN

• L3 POP breakout

Ethernet

Ethernet

ADSL

ADSL

Ethernet Fast Ethernet

Cisco 7200Cisco 7200Cisco 4xxxCisco 4xxxCisco 7200Cisco 7200Cisco 4xxxCisco 4xxx

Catalyst®®

5xxx5xxxCatalyst®®

5xxx5xxx


ADSL Ethernet model — ATM framing and transport

• RFC1483 based service

• L2 service provisioning at ADSL POP

• L3 functionCPE

Corporate site or ISP

Ethernet

ADSL

DSLAMDSLAM

ATM

LS1010LS1010 72007200

ATM VCATM VC


Ethernet to the User

• Massive market penetration, low cost, already available

• Value add via L3 functions

• Easy-of-use

• ATM transport on ADSL line

• IP over ATM options available


ATM to the User

• Multiservice capability

• ATM QoS

• PPP over ATM for single user solution

• ATM shaping required


626 Data Flow

LAN0LAN0 WAN0WAN0

Cell buffers and Management Plane

Cells Cells

• All VCs that are not identified as management cells are buffered and switched to WAN port

• Cell buffers used for ADSL transmit queue only

• 4 unique, configurable VPI,VCI combinations are passed to software SAR for use as management channels


Bandwidth Management: Architecture

• L2 end-to-end issue

• L3 local termination

• Broadcasts segmentation

• Bandwidth misused due to bridging architecture

• No access content/caching


“Classic” VPN ATM-to-ATM Solution

• Protocol Transparency

• VC between CPE router and ISP central router

• Multiple QoS classes and guaranteed levels of QoS

• IP services mapped over ATM

Ethernet

ATM

ATM PVCATM PVC


PPP/ATM ATM

PPP over ATM over ADSL with L2TP Tunnel

• Essential operational functions can be delivered using well established features in PPP/L2TP, such as:

Authentication (PAP, CHAP, etc.)

Address Administration done at the service provider gateway

Layer 3 autoconfig (DHCP, DNS, etc.)

Dynamic Selection of Multiple Destinations (via multiple PPP Sessions)

Encryption

AggregatorL2TP TunnelL2TP Tunnel

AAA Server

DNS/DHCPServ

er

ATU-R

PPP/L2TP


Applying the PPP Model to ADSL

• Easy migration for ISP (users look like dial subscribers)

• Authentication (PAP, CHAP, etc.)

• Dynamic address administration

• BUT -Still requires individual PVC for each user, for each destination

Different QoS still requires manual PVC reconfiguration

Issues for the CPE and client PC

ATU-RDSLAM

ISP / Corporate

PPP SessionPPP SessionATM

AAADNS/DHCP

Server


Applying the PPP Model to ADSL

• PPP to the desktop

ADSL NIC

ATM25 NIC with ATM25 ADSL Modem

• Challenges with Ethernet interface

CPE with PPP over ATM over ADSL

BMAP (also provides support for USB)

Others (direct PPP over Ethernet)

Issues for the CPE


Customer Premise Central Office

Cisco 675/676SOHO/Telecommuter ADSL Router

• Router based CPE for managed and L3 services

• PPP termination and routing functions

• Optional bridging option

• ADSL line termination on the router

RADSLTransport

Ethernet


DSL Transmission Technology

PPP Routing in 675/676

User Data (IP)

PPP

AAL5

ATM



RFC 1483 Bridging in 675/676

User Data(802.3 MAC)

LLC/SNAP

AAL5

ATM


Integrated PC solution

605605

PPP DriverIP PacketsCells

• ADSL line terminated on the PC card

• Multiple PPP session

• PPP frames into cells


PPP Connections in the 605/606

User Data (IP)

PPP

AAL5

ATM



Universal Access Concentrator DSLAM Aggregation

• Aggregates traffic from multiple DSLAMs onto backbone

• Full traffic management

• Differentiated services through QoS

Per VC traffic shaping

Control of access speed via ATM

• Optimises core bandwidth PacketCore

Cisco 6400

Cisco 6400

Cisco 6200

Cisco 6200

ATMCore


Universal Access Concentrator PPP Termination

• Acts as a Broadband Access Server

• Terminates PPP sessionsRadius authentication

• Massive reduction in PVC configuration

• Classifies traffic according to user attributes

ATU-R6400

AAA Server

DSLAMPPP SessionPPP Session ATM,

Packet


Universal Access Concentrator Layer 3 QoS / Layer 3 Breakout

• Per User / Per Application QoS Support for mixed IP traffic

Multimedia

Voice

WWW

Email

• VoIP breakout

• Local Content / Caching

• Multicast

DSL PoP

CCE IP/TV TIBCO

POTS/ISDNVoice Switch

Cisco 6400

Cisco 6400

Cisco 6200

Cisco 6200

Cisco AS5300

V

Cache

WWW

Email

VoIP


VPN Service: L2 and L3

ATMBackbone

Internet Backbone

AccessAccess NetworkNetworkAccessAccess NetworkNetwork

Corporate B Network

Corporate ANetwork

Connection to Corporate A

Connection to Corporate B

Layer 3 VPN Using GRE or L2TPLayer 3 VPN Using GRE or L2TP

Layer 2 VPNUsing ATM PVC

Layer 2 VPNUsing ATM PVC


System Architecture

1000 Subscribers

ADSL PoP

n

ATM Core

Business Internet

Core

ResidentialInternet

Core

VPN CoreVPN Core

IP PoPs National and International

GW PoPs

Other Services(I.e., VoD)

Other ISPs

SP Backbones

Other AccessTechnologies

GlobalInternetGlobal

Internet


ADSL PoP Contention

ADSL PoP

IP PoP

ATM Core Internet

Bandwidth


ATM Core Contention

ADSL PoP

IP PoP

ATM Core Internet

Bandwidth


IP PoP Contention

ADSL PoP

IP PoP

ATM Core Internet

Bandwidth


Content Networking ArchitectureEfficient Pull-based Network

Migration to Push-based ServiceEfficient Pull-based Network

Migration to Push-based Service

ADSL PoP

WebCaching

Web Caching Web Hosting

Web Caching


Content Management Benefits

• Optimization bandwidth use

• Insertion of local content / ads

• Value-add services

To end-users, perceivedperceived better service

To content providers

• Traffic shaping and policing required

ATM or IP QoS


Universal Access Concentrator Tunneling

• PPP Session intercepted at 6400, user identified and tunnel established based on login information

Address assigned by LNS (Tunnel destination)

Service / Destination selection based on login

Differentiated Services - tunnel selection based on subscribed QoS

• Applications -

Virtual Private Networking - Teleworking Application

Access to third party services / content

Access to third party ISP

ATU-RATU-R64006400

AAA ServerAAA Server

DSLAMDSLAM LNSLNSPPP SessionPPP SessionPPP SessionPPP Session L2TP Tunnel

ATM,

Packet

AAADNS/DHCP Server


Service Selection for the Consumer/Telecommuter Market

A+B

AAA Server

Service A

Service B

L2TP AL2TP AL2TP AL2TP A

L2TP BL2TP BL2TP BL2TP B

B

SSG

• Simultaneous connections to multiple services / service providers


• Basics

• Applications

• Architecture

• POTS splitter optionsPOTS splitter options

Agenda


Function of CPE Splitter

• Separates POTS band from composite signal

• Roll off frequency is point where pass band is 3dB down from 0 attenuation

• 8 kHz and 15 kHz roll off versions available

• Standard POTS needs only 8 kHz version.

• Centrex (CLASS) services need 15 kHz version to preserve 8 kHz QPSK loop signaling

4 kHz f1 f2

Upstream DownstreamPOTS

Roll off Frequency


Typical Home Wiring with Splitter

NIDSplitter

New Wiring(Home Run)

ExistingWiring


Splitter Options

Adjunct NID Interior Wall mount Siecor or Keptelplug-in module


Splitterless Option - EZ-DSL

• CPE Splitters are not required!

• Lower data rates and microfilters enable complete customer installation of CPE, with no wiring changes and no Telco truck roll

No new internalwiring


EZ-DSL Microfilter

• 2-pole low pass filter

• Isolates telephone load from DSL equalizer

• Isolates high frequency components from telephone handset

• Inline and wall mount versions available

213_mlucchin_rev4.ppt

Technology

cisco systems

defined213 nw98

adsl modem dslam

mbps network

remote users adsl

high data rates

adsl ratesdownstream

adsl connections