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Author Topic: Vectoring, VDSL2 Profile 35b, and Midi-DSL  (Read 7821 times)

WWWombat

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Vectoring, VDSL2 Profile 35b, and Midi-DSL
« on: June 10, 2015, 03:52:13 PM »

Has anyone heard of VDSL2 profile 35b (Annex Q)?

It seems to be an extension to VDSL2, using up to 35MHz in a way that keeps compatibility with vectoring in profile 17a (profile 30a doesn't achieve this compatibility).

As far as I can make out, it seems to be the standardised variant that has come from Huawei's Super-Vectoring, or Adtran's FDV, or Alcatel's Vplus, which seemed to be given a generic label of "Midi-DSL", and positioned between VDSL2 and G.fast.

Something here:
http://gfastnews.com/index.php/90-r/134-mdsl-midi-dsl-200-300-megabit-at-300-meters

This makes me wonder whether this will be included in this summer's G.fast trials.
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KIAB

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Re: Vectoring, VDSL2 Profile 35b, and Midi-DSL
« Reply #1 on: June 10, 2015, 03:59:09 PM »

I was looking at  KeyMile & ADTRAN Super-Vectoring ready hardware last night & spotted VDSL2 Profile 35b standard, thougt it was a typo:o

http://www.adtran.com/pub/Library/Data_Sheets/International_/I611321131F1-8%20hiX5600%20SU_SLV384.pdf


http://www.keymile.com/en/tk-trends-2015

Looking for info on the Gtech HT05 a long reach hedge trimmer,& Google threw up 'Long-Reach-G.fast' & link to Keymile, about German telco & the 35b profile

The VDSL2 profile 35b is currently undergoing the ITU-T standardisation process, which on even higher frequencies is to increase the bandwidths to medium-length copper lines of around 300 metres to up to 250 Mbps. Even higher rates are to be expected due to the Long-Reach-G.fast approach currently being debated.


« Last Edit: June 10, 2015, 04:09:29 PM by KIAB »
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WWWombat

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Re: Vectoring, VDSL2 Profile 35b, and Midi-DSL
« Reply #2 on: June 10, 2015, 04:12:55 PM »

Yes - it's the appearance of hardware like that that makes me suspect BT might include this technology in trials this summer, combined with the rumour that vectoring deployment could be stalled.

I have no more evidence than BT's statement that their target is "initial speeds of a few hundred megabits" before aiming at 500Mbps in the longer term.

Deploying hardware that is powerful enough to run G.fast in the long-term, but starts out running "just" profile 35b in the near term, might fit with BT's announcements. It could be a better decision than just rolling out 17a-vectoring linecards.
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boost

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Re: Vectoring, VDSL2 Profile 35b, and Midi-DSL
« Reply #3 on: June 10, 2015, 04:44:19 PM »

Do any of these new technologies/improvements have anything to say about latency improvements?

It would be nice to be able to get down to EFM Plus style latency or dare I say it, fibarrr!
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WWWombat

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Re: Vectoring, VDSL2 Profile 35b, and Midi-DSL
« Reply #4 on: June 11, 2015, 02:07:06 AM »

This Adtran doc reckons G.Fast has latency < 1ms, so I guess the backhaul plays a significant part.
https://www.adtran.com/web/fileDownload/doc/32246

I haven't tried looking at the provisions within G.fast for dealing with errors, so I don't know if they intend to have FEC, interleaving or retransmission-type mechanisms. Figuring what BT is doing on the current hardware is hard enough...
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ktz392837

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Re: Vectoring, VDSL2 Profile 35b, and Midi-DSL
« Reply #5 on: June 11, 2015, 08:33:24 AM »



so I don't know if they intend to have FEC, interleaving or retransmission-type mechanisms. Figuring what BT is doing on the current hardware is hard enough...
Lets hope if they do want to support those mechanisms they buy hardware that supports them.  Not that I am annoyed being stuck on an ECI cabinet and being hit by major crosstalk issues!
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boost

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Re: Vectoring, VDSL2 Profile 35b, and Midi-DSL
« Reply #6 on: June 11, 2015, 02:54:45 PM »

I think I read on one of your links that retx will be employed, as per VDSL2 deployments?

I might also have imagined the entire thing! :D
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