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

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

3. AusNOG '07 3 Why?

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

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

6. AusNOG '07 6 VDSL2+ 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 is effectively ADSL2+++++

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

8. AusNOG '07 8 Several Bandplans…(2) Annex A (US): 9 plans based on ‘Annex M’ ADSL2+ 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…

9. AusNOG '07 9 Several Bandplans…(3) 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 G.993.2 Amendment 1 Nov 2006 draft: 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! Exercise: Pick One (1) only bandplan for use throughout Australia

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

11. 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

12. AusNOG '07 12 Bandplan Choice Chosen Bandplan is European 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

13. 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

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

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

16. 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

17. 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

18. 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.

19. AusNOG '07 19 DSM Level 2

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

21. 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

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

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