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VDSL2

VDSL2. and the C559 review. Paul Brooks pbrooks@layer10.com.au. Timeline for xDSL. Feb 2006-2007. ADSL1 initially developed by AT&T/Bell Labs in 1989 to deliver video – predates the development of WWW. 2003-2007. 2002,2005-2007. 2003. 1999-2003. Why?. Agenda. DSL Redux ADSL 2+

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VDSL2

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  1. VDSL2 and the C559 review Paul Brooks pbrooks@layer10.com.au

  2. Timeline for xDSL Feb 2006-2007 ADSL1 initially developed by AT&T/Bell Labs in 1989 to deliver video – predates the development of WWW 2003-2007 2002,2005-2007 2003 1999-2003 AusNOG '07

  3. Why? AusNOG '07

  4. Agenda • DSL Redux • ADSL 2+ • VDSL2 compared • VDSL2+ Bandplans • VDSL2+ benchmarks • Bonding & Packet Transfer Mode • DSM – Dynamic Spectrum Management AusNOG '07

  5. 512 tones 25 tones upstream 473 tones downstream max ~60kbps per tone Frequency band up to 2.2 MHz ADSL2+ AusNOG '07

  6. Several Band-plans 7200+ tones (up to 30MHz) 3 upstream bands 2 or 3 downstream bands Same encoding and signalling per tone - ~ 60 kbps Frequency band up to 12/17/30 MHz VDSL2+ VDSL2 is effectively ADSL2+++++ AusNOG '07

  7. Its not as simple as ‘997 bandplans are more symmetric, 998 bandplans are more asymmetric….. Several Bandplans…(1) B8-4 is a 998 plan. B7-5 is a 997 plan B8-4 B7-5 B7-5 B8-4 Assumptions: 12 MHz band plans PIUT 40 revised No UPBO 9 x VDSL2 equal length (Example - C559 VDSL2 working group – benchmark illustration only!) AusNOG '07

  8. Annex A (US): 9 plans based on ‘Annex M’ ADSL2+ Several Bandplans…(2) • G.993.2 02/2006: • Annex B (Euro): 6 x ‘997’ plans and 7 x ‘998’ plans up to 12 MHz • Annex C (Japan): 1 band plan over ISDN, up to 30 MHz • Annexes D, E, F, G, H, I, J, K all “for further study” But wait…there’s more… AusNOG '07

  9. Annex A (US): 8 downstream x 11 upstream (some not compatible with each other) = ~80 plan variations, with max at 8/12/17/30 MHz Several Bandplans…(3) • G.993.2 Amendment 1 Nov 2006 draft: Exercise: Pick One (1) only bandplan for use throughout Australia • Annex B (Euro): 10 x ‘997’ plans and 16 x ‘998’ downstream plans up to 8/12/17/30 MHz • Annex C (Japan): 4 minor band plan variants, up to 30 MHz This VDSL2 stuff is very fresh! AusNOG '07

  10. Ob-Disclosure • Communications Alliance C559 Deployment Rules Review • Layer10 representing Preliminary information is from working drafts – subject to change before publication. AusNOG '07

  11. Multiple Bandplans don’t coexist • Frequencies that one line uses for upstream, and another line uses for downstream, interfere and destroy each other • Overall performance drops to lowest common denominator for both • Every service must use the same tones for upstream and downstream, without overlap • All must use the same bandplan AusNOG '07

  12. Bandplan Choice Chosen Bandplan isEuropean Annex B 998 Plan B8-11 to 17 MHz(from Amendment 1 still to be completed) • Little/No benefit to go to 30MHz, but 17 MHz provides good speed out to ~600m • 998 plan maximises downstream capacity for IPTV, Internet content downloads • Still retains good upstream (5-20 Mbps at 800m) – upstream capacity meets or beats eSHDSL symmetric services at all distances AusNOG '07

  13. VDSL2 Deployment Classes ADSL2+ Deployment Classes • 6h = ADSL2+ (Annex A) (unlimited distance) • 6j = ADSL2+ Annex M EU-40 • 6k = ADSL2+ Annex M EU-52 • 6l = ADSL2+ Annex M EU-56 • 6m = ADSL2+ Annex M EU-60 • 6n = ADSL2+ Annex M EU-64 VDSL2 Deployment Classes • 10h = VDSL2 • 10j = VDSL2 +Annex M EU-40 in US0 upstream • 10k = VDSL2 +Annex M EU-52 in US0 upstream • 10l = VDSL2 +Annex M EU-56 in US0 upstream • 10m = VDSL2 +Annex M EU-60 in US0 upstream • 10n = VDSL2 +Annex M EU-64 in US0 upstream NOT any of the further ‘Annex M-like’ EU-XX beyond EU-64 AusNOG '07

  14. VDSL2+ Benchmarks Benchmark: 10h modelled worst-case performance Preliminary Only – Do Not Rely On These! AusNOG '07

  15. /end C559 Back to ITU-T G.993.2… (but still subject to amendments!) AusNOG '07

  16. Other VDSL2 tricks • Bonding • 2 – 8 parallel VDSL2 services together, acting as a single channel (needs compatible CPE) • 80 Mbps upstream, 640 Mbps downstream anyone?  • Packet Transfer Mode (PTM) • Ethernet-in-the-first-mile (EFM) 802.3ah framing is supported natively • no more fiddling with ATM PVCs in the DSLAM or modem required • ~ 5% increased performance from reduced overheads AusNOG '07

  17. DSM Dynamic Spectrum Management • Adjusts transmit power in each line to time-variable external crosstalk, to optimise bandwidth for all lines in the binder by reducing cross-talk • No DSM (current situation) – assumes each line is greedy – worst-case modelling leads to conservative performance • DSM Level 1 – static spectrum shaping to avoid crosstalk – each line tries to optimise PSD shape and be polite in isolation • DSM Level 2 – dynamic spectrum shaping – each line talks to neighbours and all optimise PSD to try to be polite • DSM Level 3 – MIMO cross-talk cancellation – reverse crosstalk signal calculated and added in real-time to cancel out at the far end AusNOG '07

  18. DSM Level 2 • Algorithms developed fairly recently • Iterative Water-Filling (2002) • Optimal Spectrum Balancing (2004) • Iterative Spectrum Balancing (2005) • Autonomous Spectrum Balancing (2006) • Not available from DSLAM vendors currently, although some are preparing products and management systems to support DSM. AusNOG '07

  19. DSM Level 2 AusNOG '07

  20. DSM Level 3 • Full MIMO Crosstalk Cancellation • Ask Dr John Papandriopoulos…in about 3 – 5 years… AusNOG '07

  21. Wrapup “Its easy to offer 50Mbps access lines, if you know the top 40 Mbps will never be able to be used” Me. • Great access network speeds are one thing – be careful the backhaul can feed the access – or there is local-enough content to avoid using the backhaul AusNOG '07

  22. VDSL2 wont solve everything • Some problems will be made worse by VDSL2 AusNOG '07

  23. Thank you pbrooks@layer10.com.au www.layer10.com.au

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