VDSL2 Paul Brooks [email protected] and the C559 review.

VDSL2

Paul [email protected]

and the C559 review

AusNOG '07 2

Timeline for xDSL

Comparison of DSLTechnologies

0

5

10

15

20

25

30

35

40

45

50

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Reach (km)

Ma

x D

ow

ns

tre

am

Da

tara

te (

Mb

ps

)

VDSL2

ADSL2+

ADSL2

ADSLReADSL2

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

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

ADSL2+

• 512 tones• 25 tones upstream• 473 tones downstream• max ~60kbps per tone

• Frequency band up to 2.2 MHz

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+++++

AusNOG '07 7

Several Bandplans…(1)

0 500 1000 1500 20000

10

20

30

40

50

Length (m)

Bit

Ra

te (

Mb

ps

)

Assumptions:12 MHz band plansPIUT 40 revisedNo UPBO9 x VDSL2 equal length

B8-4B8-4

B8-4B8-4

B7-5B7-5

B7-5B7-5

B8-4 is a 998 plan. B7-5 is a 997 planB8-4 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…..

AusNOG '07 8


• 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…

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

• 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

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

0.025

ADSL2+Basis System

ADSL2+Basis System VDSL2(1)

BasisSystem

VDSL2(1)Basis

System

VDSL2(2)Basis

System

VDSL2(2)Basis

System

f (log scale)

Up

DS1b

0.138 2.208 3.75 5.2

Down

Up

8.5 12

DownUp

17.66412

Down

Down

VDSL2(3)Basis

System

VDSL2(3)Basis

System

Not yet definedNot yet defined

-54.7

-40

-56.2-58.3-60.0

-38

-51.5

DS2 DS3US2US1DS1aUS0

0.025

ADSL2+Basis System


BasisSystem

VDSL2(1)Basis

System

VDSL2(2)Basis

System

VDSL2(2)Basis

System

f (log scale)

Up

DS1b

0.138 2.208 3.75 5.2

Down

Up

8.5 12

DownUp

17.66412

Down

Down

VDSL2(3)Basis

System

VDSL2(3)Basis

System


-54.7

-40

-56.2-58.3-60.0

-38

-51.5


ADSL2+Basis System


BasisSystem

VDSL2(1)Basis

System

VDSL2(2)Basis

System

VDSL2(2)Basis

System

f (log scale)

Up

DS1b

0.138 2.208 3.75 5.2

Down

Up

8.5 12

DownUp

17.66412

Down

Down

VDSL2(3)Basis

System

VDSL2(3)Basis

System


-54.7

-40

-56.2-58.3-60.0

-38

-51.5


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

ADSL2+ vs VDSL2 Upstream Benchmarks

0

2

4

6

8

10

12

14

16

18

20

0 0.5 1 1.5 2 2.5

Reach (km)

Do

wn

str

ea

m D

ata

rate

(M

bp

s)

VDSL2 upstreambenchmark (800m ref)ADSL2+ upstreambenchmark

ADSL2+ vs VDSL2 Downstream Benchmarks

05

10152025303540455055606570

0 0.5 1 1.5 2 2.5

Reach (km)

Do

wn

stre

am D

atar

ate

(Mb

ps)

VDSL2 Benchmark

ACIF Benchmark

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

Thank you

[email protected]

www.layer10.com.au

VDSL2 Paul Brooks [email protected] and the C559 review.

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