xDSL Access work in ITU-T Study Group 15 Presented by: Paolo ROSA Counsellor – ITU-T Study Group 15 Optical and other transport networks

Contents About ITU-T SG 15 Access Scenarios xDSL Access

About Study Group 15 (www.itu.int/ITU-T/studygroups/com15)

ITU-T Study Group 15 Responsible for studies relating to: optical and other transport networks, systems and equipment including transmission layer related standards for access, metropolitan and long haul sections of communication networks and relevant G-series Recoimmendations. Lead Study Group on Access Network Transport (ANT) Optical Technology

ITU-T SG 15 Access Network Transport - Targeted Work and Standardization Plans Finalize a Standardization Plan for: identify existing Recs and standards identify areas of overlapping identify any missing area resolving standardization issues for ANT investigate needs for new Recommendations (www.itu.int/ITU-T/studygroups/com15)

Many a type of access SAT Broadcast Cable UNI Access Network Home Network Broadcast Access Network Distribution Network Cable Longhaul Copper or F.O. Copper F.O. UNI SNI

ITU-T Study Group 15 Structure http://www. itu Optical and other transport networks Peter Wery ITU-TSB Counsellor Paolo Rosa Working Party 1 Network Access Andrew Nunn Working Party 2 Network Signal Proc. Yushi Naito Working Party 3 OTN Structure Stephen Trowbridge Working Party 4 OTN Technology Gastone Bonaventura Working Party 5 Projects and Promotion Haruo Okamura

Access Scenarios

Typical Access Network Construction Central Office (Exchange) Street Cabinet Distribution Network Feeder Network Underground Feed Overhead Feed

Access technological evolution G-PON 2.5 Gbit/s OPTICAL ACCESS 622 Mbit/s 50 Mbit/s VDSL 25 Mbit/s 8 Mbit/s HDSL/ ADSL 2 Mbit/s 640 kbit/s ISDN 128 kbit/s Analog modems 56.6 kbit/s 28.8 kbit/s 9.6 kbit/s Year 1989 1997 2000 2003

Capacity, technologies & availability ISDN 100 1k 10k 100k 1M 10M 100M 1G 1980 1990 2000 2010 2020 Year Bit rate per user ( bit/s) PSTN / Modem ADSL SDSL FTTH double in 18 mon . double in 24 N.B. The technology bars show the introduction, not the end of the technology VDSL, FTTCab There will never be enough! The bandwidth demand will continue to grow. Fiber to the home will be necessary sooner or later. Source Siemens

Optical access network architecture (G.983.1) Optical Distribution Network FTTH O N U O L T Fibre Copper FTTB/C N T O N U Fibre SNI HOME Copper Fibre N T O N U FTTCab Access network

Access Network Transport Reference Model Customer Premise Core Network Wireless Phone Access Unit [X] Service Function TV PC Core Network [Y] L XNI CP1 x WI1 SNI S1 C1 yn xxn Q Access Network (AN) Network (CPN) (CN) CX1

Access Network Scenarios – 1 - 2   Scenario 1 Services a) Voice/Data over telecom network and Video over cable, radio&DSB b) Voice/Data/Video over 2- way cable Core Network Existing Infrastructure (PSTN/N-ISDN) Access network 1-way Cable Distribution Network b) 2-way Cable Distribution Network DSB/terrestrial broadcasting in 1 a) CPN Access Unit TV, PC, Phone Information Flow a) Video Distribution over 1-way cable network, return via PSTN/ISDN a) Voice/Data over telecom network and Video over cable b) Voice/Data/Video over 2-way cable B-ISDN

Access Network scenarios – 3 - 4   Scenario 3 Scenario 4 Services Voice/Data & Video over ADSL/VDSL Voice/Data & Video over Fibre Network Core Network B-ISDN Access network ADSL/VDSL Fibre (Fibre to the curb/home) CPN Access Unit TV, PC, Phone Information Flow

The use of ADSL or VDSL for video bandwidth over copper pairs Scenario 3 The use of ADSL or VDSL for video bandwidth over copper pairs Service Function {Video} Core Network (N-ISDN) (B-ISDN) Access [ADSL] [VDSL] SNI S1 C3 XNI CP3 CP2 C4 Unit CPN TV PC Phone

Fibre Access – FTTC - FTTH – FTTB Scenario 4 Fibre Access – FTTC - FTTH – FTTB Service Function {Video} {Internet} Core Network (B - ISDN) Access [FTTC] [FTTB] [FTTH] SNI C 5 DI CP 3/4 OA 1 6 Unit FTTH CPN TV PC Phone FTTC FTTB

ANT – Scenario 5 Scenario 5 Services   Scenario 5 Services a) Wireless Phone Voice/Data over telecom network and Video over cable b) Voice/Data/Video over Radio Core Network N-ISDN or B-ISDN Access network Radio/Wireless for Voice/Data - Cable for a) Video CPN Access Unit TV, PC, Phone, wireless Phone Information Flow 2-way wireless

The use of Radio in the Local Loop Scenario 5 The use of Radio in the Local Loop PC CPN Access Unit TV Wireline Phone [CATV] Service Function {Video} Core Network (N-ISDN) [Wireless] SNI S 1 C 2 XNI CX 7 CP WI [N - ISDN] Wireless

ANT Scenarios 6 - 7 Scenario 6 Scenario 7 Services   Scenario 6 Scenario 7 Services B-ISDN, Internet and Mobile Phone via Satellite a) Data over Internet Voice/Video and/or Data over Internet Core Network B-ISDN or Existing (N-ISDN) a) POTS/FR/ATM b) ATM Backbone Access network Satellite a) ADSL/VDSL b) PSTN/ISDN, HFC, PON c) Fixed wireless Access CPN Access Unit: TV, PC, Phone Information Flow 2-way satellite

Scenario 6 - Access using satellites NT- function X NI WI3 XNI WI4 SA1 L F ISP port server B S A1 Access Unit (Gateway Earth Station) Access Network PSTN or ISDN Switch A SNI C1 CP5 CP1 Physical Presentation C8 Telecommunications Network SA 1 Phone PC Video Access Unit (s) CPE Mobile Satellite BISDN Satellite

Example of Internet Access Scenario 7 Example of Internet Access Splitter Edge Switch Service Function { Video,etc} Core Network (N - ISDN) Access [ADSL] {Internet} SNI S 1 C 3 2 XNI CP Unit CPN TV PC Phone

xDSL Access

xDSL Market & Business Drivers xDSL technology allows the provision of high-speed Internet access and other broadband services over existing copper telephone lines Incumbent operators need to exploit their large installed base of copper access lines for broadband deployment Competing operators can exploit incumbent operators access lines via ‘unbundling’ agreements Competition: Digital Cable / Cable Modem Bi-directional Satellite

Typical components of an xDSL system ADSL2+ ADSL2 ADSL ADSL lite HDSL SHDSL VDSL audio/video/data CUSTOMER PREMISES CENTRAL OFFICE xDTU-R xDTU-C T SNI • B-ISDN SN xDT xDT • Non-ATM based SN (e.g. - video server - IP router) U-R U-C POTS POTS • PSTN/ISDN Splitter Splitter (Subscriber line) SN xDT xDSL Transceiver DTU-R = Transceiver Unit- Remote DTU-C = Transceiver Unit- Central office = SN = Service Node xDSL

ITU-T Recommendations on ADSL (1) G.991.1 (G.hdsl) - High bit rate Digital Subscriber Line (HDSL) transmission system on metallic local lines. G.992.1 (G.dmt) - Asymmetrical Digital Subscriber Line (ADSL) Transceivers. G.992.2 (G.lite) - Splitterless Asymmetrical Digital Subscriber Line (ADSL) Transceivers. G.992.3 Asymmetric digital subscriber line transceivers - 2 (ADSL2.dmt) G.992.4 Splitterless asymmetric digital subscriber line transceivers - 2 (ADSL2.lite)

ITU-T Recommendations on ADSL (2) G.992.5 – Asymmetric Digital Subscriber Line (ADSL) Transceivers – Extended Bandwidth ADSL2 (ADSL2plus) (Jan ’03) G.995.1 - Overview of Digital Subscriber Line (DSL Recommendations). G.991.2 (G.shdsl) - Single pair High bit rate speed Digital Subscriber Line G.993.1 (G.vdsl) - Very high bit-rate Digital Subscriber Line G.994.1, G.996.1 and G.997.1 for tests, management and handshake

ADSL2+ ADSL2 ADSL VDSL SHDSL HDSL Video/ voice/ data/copper G.992.5 Video/ voice/ data/copper 16 Mb/s Down Up to 800 Kb up Higher-optional video capabilities. Ext reach/BW ADSL2 With and without splitter – G.992.3 / 4 8 Mb/s down 800 Kb/s up Ext reach ADSL With and without splitter – G.992.1 / 2 Voice/data /copper Up to 8 Mb/s down Up to 1.5 Mb/s up Full use existing copper. Web brows/Voice VDSL Symmetric Asymmetric G.993.1 Video/ voice/ data (V/V/D) over copper Up to 52 Mb/s down asymm Up to 26 Mb/s Symm. Broadcast video, VoD, internet TV, V/V/D serv SHDSL G.991.2 Voice/data/ Video 1/2 pairs 192 K to 4.6 M Steps 8/16 Kb/s Poss amplif. V/V/D Services mainly for business appl. HDSL Symmetric G.991.1 Voice data and video 1/2/3 pairs 784 Kbit/s to 2320 Kbit/s

G.991.2 (SHDSL) transceivers Multi-rate transmission technology duplex operation over only two-wire twisted metallic pairs. (G.991.1 is for 1-3 pairs). Symmetric data rates (scalable): One pair mode: 192 kbit/s to 2312 Kbit/s (single pair mode), in increments of 8 kbit/s, distance from 1.8 up to 6.5 km. Two-pair mode: 384 kbps to 4.624 Mbps Many Manufacturer’s options 4-wire operation Repeaters, etc.

Symmetric and asymmetric data rates G.993.1 (VDSL) transceivers Symmetric and asymmetric data rates Downstream as high as 5 to 20 Mbit/s Upstream 1.6, 2.3, 19 Mbit/s or equal to downstream in case of symmetric tx. American/Japanese/European (Annexes: spectrum bandplans for national regulators) 300 – 1 500 m. reach

G.992.1 - Asymmetric Digital Subscriber Line transceivers One twisted pair Payload upstream up to 640 kbit/s Downstream up to 6.144 Mbit/s Simultaneous Voiceband and N-ISDN possible Line Code - DMT (Discrete MultiTone)

G.992.2 - Splitterless asymmetric digital subscriber line transceivers One twisted pair Payload downstream up to 1.536 Mbit/s Upstream up to 512 kbit/s Line Code - DMT (Discrete MultiTone)

ADSL versus ADSL2 (G.992.1 x G.992.3) 2nd generation of ADSL with improvements on: Loop-reach increase for equivalent bit rates (300m) Higher down/up bit rates loop diagnostics Adjustable spectrum shaping during operat/initializ Power vs traffic control: L0(full),L1, L2 robustness against loop impairments and RFI Improved multivendor interoperability Improved application support for an all digital mode of operation and voice over ADSL operation;

ADSL 2 Performance Improved initialization Fast Start up : 3 seconds Downstream: 8 Mbit/s to 15 Mbit/s Upstream: 800 Kbit/s to 1.5 Mbit/s Data rate on long distances Improved initialization Fast Start up : 3 seconds Fast return to L0 status full operation (0.5 s) Additional 256 Kbit/s upstream data rate In-line filters for home installation Backwards/Legacy compatibility

ADSL 2 plus - G.992.5 Performance Increase downstream: to 16 Mbit/s Maybe increase in upstream (Oct. 2003) Increase reach (1.5 - 3 Km) ADSL + doubles the bandwidth (from 1.1 to 2.2 MHz) with a significant increase of data rates on short loops Backwards compatibility (needs G.992.3)

Things in progress in SG15 Network access Home networking (data on in-premises wiring) Refinements & enhancements xDSL Web-based ANT standardization plan Optical Transport Network (OTN) x-WDM and 40Gbit/s signal channels Optical Cross-Connect and Switch Fiber characteristics, more channels/fiber Network Node Interface for OTN Continue as Lead Study Group on Access Network Transport Optical Technology

Q.4/15 - Transceivers for customer access and in-premises phone line networking systems on metallic pairs Current/future work Revision of Single-pair High-speed DSL (SHDSL) - G.991.2 G.992.3 Annex C : ADSL in same ISDN cable G.992.3 Annex L : reach extended ADSL over POTS G.992.5 Annex J : improved Spectral Compatibility with ADSL over ISDN improved Spectral Compatibility with ADSL over ISDN G.992.5 Annex L : extended upstream bandwidth Very high bit rate DSL (VDSL) – G.vdsl.l

CONCLUSIONS An overview on the standardizations activities in ITU-T SG 15 was presented The most recent standards for access network approved and consented in October 2002 and January 2003 were shown Access scenarios, current and future work provide information about the next future in the field of access copper network technologies

Thank you for your attention! For further contact, please feel free to contact: Counsellor for SG 15: Paolo Rosa Paolo.rosa@itu.int Tel: +41-22-730-5235 Fax: +41-22-730-5853 http://www.itu.int/ITU-T