Introduction To Xdsl Technology
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© 1999, Cisco Systems, Inc.
Introduction to xDSL Technology Session 203
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Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. 1085_06F9_c1.scr
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Abstract
“
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
5
© 1999, Cisco Systems, Inc.
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
3
Broadband Access Technologies
• DSL (copper) • Cable (coax) • Wireless • Optical Fiber
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© 1999, Cisco Systems, Inc.
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
9
© 1999, Cisco Systems, Inc.
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
5
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
© 1999, Cisco Systems, Inc.
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
© 1999, Cisco Systems, Inc.
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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
© 1999, Cisco Systems, Inc.
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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© 1999, Cisco Systems, Inc.
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
19
© 1999, Cisco Systems, Inc.
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
23
© 1999, Cisco Systems, Inc.
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
12
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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© 1999, Cisco Systems, Inc.
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
13
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
© 1999, Cisco Systems, Inc.
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
”
© 1999, Cisco Systems, Inc.
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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
31
© 1999, Cisco Systems, Inc.
Please Complete Your Evaluation Form Session 203
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1
© 1999, Cisco Systems, Inc.
Introduction to xDSL Technology Session 203
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© 1999, Cisco Systems, Inc.
Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. 1085_06F9_c1.scr
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Abstract
“
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.
203 1085_06F9_c1
”
© 1999, Cisco Systems, Inc.
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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
© 1999, Cisco Systems, Inc.
Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. 1085_06F9_c1.scr
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2
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
5
© 1999, Cisco Systems, Inc.
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
© 1999, Cisco Systems, Inc.
Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. 1085_06F9_c1.scr
60x
70x
80x
90x
100x 6
3
Broadband Access Technologies
• DSL (copper) • Cable (coax) • Wireless • Optical Fiber
203 1085_06F9_c1
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© 1999, Cisco Systems, Inc.
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
203 1085_06F9_c1
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4
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
9
© 1999, Cisco Systems, Inc.
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
© 1999, Cisco Systems, Inc.
Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. 1085_06F9_c1.scr
Average voice call lasts three minutes, compared to 30-60 minutes per internet session 10
5
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
© 1999, Cisco Systems, Inc.
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
© 1999, Cisco Systems, Inc.
Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. 1085_06F9_c1.scr
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6
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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7
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
© 1999, Cisco Systems, Inc.
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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8
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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© 1999, Cisco Systems, Inc.
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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9
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
19
© 1999, Cisco Systems, Inc.
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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10
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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21
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
23
© 1999, Cisco Systems, Inc.
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
12
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
25
© 1999, Cisco Systems, Inc.
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
13
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
© 1999, Cisco Systems, Inc.
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
203 1085_06F9_c1
• Defending their residential access franchise • Off-loading internet data traffic from the voice network
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14
This Changes Everything…
“ Broadband Internet Access Threatens POTS Subscriber Loyalties That Have Withstood Decades of Low-price Come-ons 203 1085_06F9_c1
”
© 1999, Cisco Systems, Inc.
29
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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15
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
31
© 1999, Cisco Systems, Inc.
Please Complete Your Evaluation Form Session 203
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203 1085_06F9_c1
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