Cisco - Introduction to xDSL Technology 203

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© 1999, Cisco Systems, Inc.

Introduction to xDSL Technology Session 203

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Abstract

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Introduction to DSL Technology Digital Subscriber Line (DSL) technology unlocks the potential of conventional copper pair telephone wire to deliver high-data-rate ("broadband") digital services. Learn how this technology "turbo charges" the telephone wires available at virtually every business and residence, and how this technology will effect you as a service provider, enterprise customer, and everyday consumer. DSL is one of the leading technologies for bringing "megabits to the masses" in the new emerging age of ubiquitous broadband access. This session includes introduction to the family of DSL technologies ("xDSL"); describes how this technology enables delivery of high-speed data, voice and multimedia over conventional telephone wires; overview of the equipment required to build a DSL network on top of existing telephony infrastructure; description of value-added services enabled by "mass-market" broadband access.

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Agenda • • • • • • • 203 1085_06F9_c1

What Is “Broadband”? Why Is It Important? What Is DSL? DSL Technology Overview Basic DSL Network Design New World Services Market Dynamics

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Life Beyond 56K 56K Is Too Slow to Provide a Satisfactory Consumer Internet Experience • Our century-old telephone network is designed specifically around the audible frequency range 0-4 kHz • Voice-band modems use tones in the audible spectrum and communicate via standard voice circuits (You can hear modems and fax machines “talking” to one another) • 56 kbps (“56K”) is the practical limit for voice-band modems • DSL uses inaudible high-frequency signaling to achieve megabit-transmission speeds 203 1085_06F9_c1

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What is “Broadband”? “Broadband” = “Megabit” Data Rates • Common unit of measure: “T-1” = 1.544 Mbps • “Fractional” T-1s, starting around 384 kbps • Compare to current maximum voice-band modem speed of 56 kbps (“56K”)… 56K

384K 7x

1Mb 18x

T-1 27x

2Mb

4Mb

36x

70x

10x 203 1085_06F9_c1

20x

30x

40x

50x

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60x

70x

80x

90x

100x 6

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Broadband Access Technologies

• DSL (copper) • Cable (coax) • Wireless • Optical Fiber

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Consumer Access Options Transmission Download Speed Medium

Upload Speed

Requirements and Limitations

Equipment Cost

Installation Cost

Monthly Expense

Target Market

Analog

Copper (Std. Phone Wire)

56 Kbps (Typically less)

33.6 Kbps (Or Less)

Slow, But Available Everywhere

$0 (Typically Included with PC)

$0 (With Existing Phone Line)

Cost of Phone Line + $19 for ISP

Residential

ISDN

Copper (Std. Phone Wire)

64 Kbps or 128 Kbps

64 Kbps or 128 Kbps

Reach Extends Several Miles with Repeaters

$75 Terminal Adapter to $500 Router

Up to $300

$19-$39 + $19-$39 for ISP

Residential and Business

ADSL

Copper (Std. Phone Wire)

144 Kbps to 8 Mbps

144 Kbps to 1.7 Mbps

<18K ft. from CO, No DLC

$200 PC NIC, $500 SOHO Router (Unless Rented)

Up to $500

$39 (Min), May Include Internet Connection

Residential and Business

Cable Modem

Coax

384 Kbps to 4 Mbps

128 Kbps to 4 Mbps

Requires Cable TV Availability; Speed Varies Noticeably with Subscriber Load

Up to $349 for Set-Top Modem, Unless Rented, Plus $29 (Min) for Ethernet NIC

Up to $175

$29-$49 (Min), Include Internet Connection; May Include Equip. Rental

Residential

Satellite

Wireless Req.'s (Phone Line Return Path)

400 Kbps

33.6 Kbps (Via 56K Analog Modem)

Requires “Dish” Antenna and Phone Line

$199 (Min.)

Up to $800

Cost of Phone Line + $29-$129, Include Internet Connection

Residential

LMDS (Fixed Wireless)

Wireless

1.5 Mbps to 4 Mbps

1.5 Mbps to 4 Mbps

Requires Antenna

Negotiated, Depends on Serv. Package

Negotiated, Depends on Serv. Package

Varies Widely, Depends on Serv. Package

Business

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Business Access Options Service

Installation

Monthly

Leased Line T-1 (1.5 Mbps)

$750-$1,500

$1,200-$1,600

Frame Relay (384 kbps)

$700-$1,200

$550-$850

Business ISDN (128 kbps)

$100-$350

$100-$250

DSL (1.5 Mbps)

$400-$1,000

$900

DSL (384 kbps)

$100-$350

$100-$150

Deregulation and Access to “Dry Copper” Has Created a Market for CLECs and IXCs to Provide Lower-cost DSL Access As an Alternative to Reselling Traditional Local Loops 203 1085_06F9_c1

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Why is Residential Broadband Important? RBB Enables the Full Commercial Potential of the Internet • Fast downloads of “rich” content Graphics, animation, audio, and video

• Integrated services Data,Voice, and Video

• New Services Variable bandwidth, additional lines on-demand, multimedia conferencing

• Always on Constant interaction with a multitude of network-aware “Internet appliances”

• Real-time, person-toperson interaction

• Relieves voice networks overloaded with Internet traffic

Video conferencing, interactive gaming, multimedia collaboration 203 1085_06F9_c1

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Average voice call lasts three minutes, compared to 30-60 minutes per internet session 10

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What Is “DSL”? • A family of access technologies that utilize high-transmission frequencies (up to 1 MHz) to convert ordinary phone lines into high-speed data conduits SDSL P O T S 0 203 1085_06F9_c1

ADSL

4 kHz

1 MHz 11

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DSL 101 End-User DSL

Enet DSL “Modem”

ATM Copper Loop

DSL “Modem”

Value-Added Packet Network

• DSL is a pair of “modems” on either end of a copper wire pair • DSL converts ordinary phone lines into high-speed data conduits • Like dial, cable, wireless, and T1, DSL by itself is a transmission technology, not a complete end-to-end solution • End-users don’t “buy” DSL, they “buy” services, such as high-speed Internet access, intranet, leased line, voice, VPN, and video on demand 203 1085_06F9_c1

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DSL Modem Technology DSL Technology

Max. Max. Data Data Rate Rate Down/Uplink Down/Uplink (bps) (bps)

Line Line Coding Coding Technology Technology

Baseband Baseband Voice? Voice?

Max. Max. Reach Reach Feet Feet (km) (km)

Key Key Attributes Attributes

VDSL VDSL –– Very-High-Bit-Rate Very-High-Bit-Rate DSL DSL

51-55M/1.6-2.3M 51-55M/1.6-2.3M 13M/1.6-2.3M 13M/1.6-2.3M

TBD TBD

Yes Yes

1,000 1,000 (0.3) (0.3) 4,500 4,500 (1.5) (1.5)

Very Very Fast—Short Fast—Short Reach Reach No No Standard Standard Yet Yet

ADSL ADSL –– Asymmetric Asymmetric DSL DSL

8M/1M 8M/1M 1.5M/640K 1.5M/640K

CAP, CAP, DMT, DMT, G.lite G.lite

Yes Yes

18,000 18,000 (5.5) (5.5)

Coexists Coexists with with POTS POTS Technology Technology of of Choice Choice for for Residential Residential

IDSL IDSL –– ISDN ISDN DSL DSL

144K/144K 144K/144K

2B1Q 2B1Q

No No

18,000 18,000 (5.5)+ (5.5)+ (w/repeaters) (w/repeaters)

Uses Uses Existing Existing ISDN ISDN CPE CPE Relatively Relatively Slow Slow

768K/768K 768K/768K

2B1Q/CAP 2B1Q/CAP

No No

22,000 22,000 (6.9) (6.9)

Symmetric Symmetric No No standard standard

1.5M-2M/1.5M-2M 1.5M-2M/1.5M-2M (T1-E1 (T1-E1 Symmetric) Symmetric)

OPTIS OPTIS

No No

15,000 15,000 (4.6) (4.6)

Standard Standard Still Still under under Development Development

SDSL SDSL –– Symmetric Symmetric DSL DSL HDSL2 HDSL2 –– High-Bit-Rate High-Bit-Rate DSL DSL

• Trade-off is reach vs. bandwidth • Reach numbers are best-case assuming “clean copper” • Different Layer 1 transmission technologies, need a common upper protocol layer to tie them together 203 1085_06F9_c1

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ADSL “Consumer DSL” • Designed to co-exist with POTS, unlike most other DSL types • “Slow” upstream for low-data-rate requests • “Fast” downstream for bursts of rich graphics and multimedia content • Three basic “flavors” of ADSL (modulation techniques) CAP (Carrierless Amplitude modulation/Phase modulation) DMT (Discrete MultiTone modulation) G.lite (Consumer/mass-market DMT) 203 1085_06F9_c1

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ADSL and POTS A Key Feature of ADSL Is Co-Existence with POTS Standard Analog Phone Microfilter

Analog Voice

DLC

Class 5 Switch

NID

PC

ADSL CPE

POTS + ADSL

Customer Premise • • • • 203 1085_06F9_c1

POTS Splitter

ADSL DSLAM

Central Office

Permits transmission of both signals on the same wire pair Off-loads data circuit from the voice switch “POTS Splitter” at the CO separates analog POTS from data “Microfilters” at the customer premise prevent off-hook interference between analog voice signal and ADSL signal 15

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G.lite “Mass-Market DSL” • Simplified DMT encoding scheme • Limited “features” to facilitate broad interoperability and minimize end-user interaction • No embedded management channel • “Splitterless” • Max. downstream data rate = 1.5 Mbps • Max. upstream data rate = 640 kbps 203 1085_06F9_c1

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ADSL Standards

• Full-rate DMT ANSI T1.413—Issue 2 ITU G.992.1 (G.dmt) ITU G.994.1 (G.hs)

• Consumer DMT ITU G.992.2 (G.lite) 203 1085_06F9_c1

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Interoperability

Why it’s good…

Why it’s difficult…

• Enables competition and lower equipment costs for service providers and end-users

• Standard must specify physical layer (at all data rates) and framing

• Lower component costs for equipment manufacturers

• Value-added services require Layer 2/3 implementations

• Proliferation of CPE options for end-users

• Standards development takes time

• Retail availability of CPE (consumer mass market)

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End-To-End DSL Protocol Stack Application

Application Protocols

Layer 3

IP

Layer 2

Application Protocols

IP

PPP

PPP

AAL5

AAL5

ATM Layer 1

ATM DSL

End-User

Telco Network

ISP

Content Provider

Aggregator

Content Server

ATM Backbone CPE 203 1085_06F9_c1

DSLAM

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The Epic Battle: DSL vs. Cable

Monday, May 24, 1999

DSL Beats Cable in Net Speed Services Tested During ‘Rush Hour’

April 20, 1999 • Performance and new-world services depend more on the network design than the transmission technology • Cable companies have an early lead

The Faster Web DSL, Cable, and Satellite

Editors’ Choice: Cable Modems

• The Telcos have awakened 203 1085_06F9_c1

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DSL vs. Cable Bake-Off DSL

Cable

Dedicated Dedicated Vs. Vs. Shared Shared

DSL DSL Is Is aa Dedicated Dedicated Connection: Connection: •• No No bandwidth bandwidth contention contention •• Secure Secure

Cable Cable Is Is aa Shared Shared Wire: Wire: •• Noticeable Noticeable speed speed impairment impairment during during “rush “rush hour” hour” •• Near-term Near-term security security issues issues

Availability Availability

Telephone Telephone Wires Wires Are Are Universally Universally Available Available to to Nearly Nearly Every Every Business Business and and Residence Residence

Existing Existing Cable Cable Is Is Almost Almost Exclusively Exclusively Residential Residential

Accessibility Accessibility

Approx. Approx. 15% 15% of of Current Current Customers Customers Are Are Inaccessible Inaccessible (Out-of-reach, (Out-of-reach, Bad Bad Copper, Copper, Etc.) Etc.)

Cable Cable Head-end Head-end Equipment Equipment Must Must Be Be Upgraded Upgraded or or Replaced Replaced for for Two-way Two-way Communication Communication

Impairment Impairment Susceptibility Susceptibility

Telephone Telephone Wires Wires Are Are Susceptible Susceptible to to High-frequency High-frequency Cross-talk Cross-talk and and External External Impairment Impairment

Cable Cable Is Is Shielded— Shielded— Signal Signal Impairment Impairment Is Is Not Not aa Problem Problem

Customer Customer Support Support

Established Established Customer Customer Support Support Models Models and and Systems Systems for for Data Data Services Services and and Per Per Subscriber Subscriber Outages Outages

Data Data Service Service Is Is New New and and Operations Operations Model Model Is Is Broadcast Broadcast Oriented Oriented

Consumer Consumer Awareness Awareness

Telcos Telcos Are Are the the Incumbent Incumbent for for Voice Voice and and Data Data

Cable Cable Companies Companies Are Are Moving Moving Aggressively Aggressively

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Basic DSL Network Components DSL CPE Customer Premise Equipment PC NICs, bridge/routers, enterprise routers

DSLAM DSL Access Multiplexer Concentrates individual subscriber lines from CPE

Aggregator/service selection gateway Concentrates ATM feeds (T-1, DS-3, OC-3) from DSLAMs PPP termination, Layer 2 and 3 service selection On-demand, personalized services Accounting and billing 203 1085_06F9_c1

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• Local Voice Services • Managed Voice and Data VPNs • Additional Lines On-demand

• Private Line Replacement • Video Conferencing • Video on Demand • High-speed Internet Access 203 1085_06F9_c1

More Bandwidth = More Services = More Profit Opportunities

Basic DSL Network Topology Cisco 2600/ 3600

LEC

ISP

Home Gateway Cisco 3600, 6400, 7200

Power Branch Cisco Cisco 6100/6200 6100/6200 Cisco 1400/ 1700

ATM Backbone

Small-Medium Enterprise Cisco 600

Residential

Enterprise Service Selection Gateway

Cisco Cisco 6400 6400 Aggregator Aggregator

Cisco Cisco 90i 90i

Packet Backbone Cisco 6400 Network Management and Provisioning

V Voice Gateway Cisco AS5300

Internet

Cisco 600/700/ 800/1000

Home Office, Telecommuter

Home Gateway Cisco 6400, 7200

PSTN

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Telephone Company Deployment Options • Central office Locate DSLAM in central offices (COs) for best coverage in cities, dense suburbs

City

• Remote terminal Locate DSLAM in unmanned remote terminals (RTs) for expanded coverage in suburbs and rural areas—very common in new developments

CO

RT

• Collocation In some countries, competitive carriers can obtain CO space from incumbent carriers and lease “dry” copper loops to reach customers 203 1085_06F9_c1

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Suburbs

Suburbs, Rural 24

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Private Copper Deployment Options • DSL can be effective wherever there is existing copper • In-building networks Located in the basement or telco closet of hotels, apartment buildings, or office buildings

• Campus-style networks Located centrally to serve multi-building campus networks, such as office parks and apartment complexes 203 1085_06F9_c1

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New World Services Voice over Data Video Conferencing E Commerce Distance Learning Secure VPN Internet Access

Today 203 1085_06F9_c1

Consumer

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Business 26

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Exploding DSL Marketplace Performance Alternative to PSTN/ISDN: High-Speed, Always-On Network Access…

Branch Enterprise

PSTN ISDN

Dialup

ISP and/or Enterprise

Small-toMedium-sized Enterprise

Telecommuter

DSL Access

Residential 203 1085_06F9_c1

Price …and an Alternative to T1, DDS, Traditional Access nxDS0 Loops for Lower Cost 27

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Market Dynamics

Attack

Defend

• CLECs are pursuing small businesses that have had only limited data access options

• ILECs are reacting to the onslaught of cable modems

• T-1 service has been too expensive and an overkill • ISDN is too slow

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• Defending their residential access franchise • Off-loading internet data traffic from the voice network

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This Changes Everything…

“ Broadband Internet Access Threatens POTS Subscriber Loyalties That Have Withstood Decades of Low-price Come-ons 203 1085_06F9_c1

”

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More, Better, Faster, Cheaper Consumer Proposition • It’s no longer just about cheaper phone bills… • Now it’s about high-speed Internet access… • And, “Oh, by the way”, bundled voice lines… • And, value-added voice/data/video services!

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Summary • DSL is ready for prime time! • Data-traffic volumes are eclipsing voice-traffic volumes on the public networks • Carriers have tested DSL, and now need to scale for mass deployment • Profits in an era of low-cost access will come from new- world services 203 1085_06F9_c1

Data

Voice

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Please Complete Your Evaluation Form Session 203

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