View
220
Download
3
Category
Preview:
Citation preview
VDSL2
Paul Brookspbrooks@layer10.com.au
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
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…
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
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
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
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
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
pbrooks@layer10.com.au
www.layer10.com.au
Recommended