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Author Topic: A heads-up - [VCMM line cards change out].  (Read 9543 times)

kitz

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Re: A heads-up - [VCMM line cards change out].
« Reply #15 on: April 01, 2015, 01:11:48 AM »

So what your saying is the tones being effected by RFI are notched out/unavailable by the RFI profile, don't think I would like this applied to my line as the RFI comes and go's over a 24 hour period, so notching out the RFI tones/bands 24/7 would impact my attainable sync and thus lower sync rate but the DS SNRM would also become steady  :-\

This notching has always been available although BT (nor any other UK ISP bar one) has never used it.   BE* were the first ISP that I became aware of using it on their Alcatel ISAMs (MSAN by another name).  It was never popular with Be/02 subscribers who were affected by it, because it stopped some users being able to attain full sync speeds.  The notch was at the high end of the adsl2+ spectrum so it didn't make any difference though to those on short(er) lines.
Ironically I suggested to Konrado early on that this is what his ISP could be doing, but it was always dismissed.  It was only later when he found out from his ISP that they had installed some new DSLAMs...  which co-incidentally turned out to be the same Alcatels ISAMs used by Be/O2.
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WWWombat

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Re: A heads-up - [VCMM line cards change out].
« Reply #16 on: April 01, 2015, 04:59:52 AM »

Found this, below .....

'Modems that do not support (A)ELEM will adversely affect those that do. This is due to the incorrect upstream power back off being applied'.

Interesting.

I was commenting in a thread over on TBB, where a user had some latency problems after G.INP activation. This was a line that was sync'ed at 80/20, with G.INP enabled, but had attainable of 95/45 - a notably high upstream attainable speed.

When compared against my line (currently 107/35 attainable with G.INP), I could see his line had slightly higher attenuation, but was otherwise configured identically for all G.INP settings; it looked like this was NOT the cause of the issue. However, the power values on the upstream were huge in comparison - my upstream power was -8dBm, his was +8dBm.

I remember commenting that it looked like the UPBO wasn't working right, and that perhaps this was having some knock-on impact to latency (but I haven't a clue why that would be).
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kitz

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Re: A heads-up - [VCMM line cards change out].
« Reply #17 on: April 05, 2015, 11:37:47 PM »

Quote
latency problems after G.INP activation. This was a line that was sync'ed at 80/20, with G.INP enabled, but had attainable of 95/45 - a notably high upstream attainable speed.

/snip/

this was having some knock-on impact to latency (but I haven't a clue why that would be).

I cant think why either, but you know how sometimes when a line is interleaved it can do weird things to the max attainable.  One of the symptoms of the latest g.inp issues is it looks like the line is interleaved but its not showing up anywhere - link
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boost

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Re: A heads-up - [VCMM line cards change out].
« Reply #18 on: April 06, 2015, 12:51:59 AM »

Quote
Upon first glance it looks as if interleaving has been enabled, but a line test shows that this is not the case.

I've been wondering what they mean by this. Service tests do indeed show profile changes but that is presumably DLM data. I wonder if the cabs are applying interleaving without direct instruction from DLM, thus the +15ms is indeed caused by interleaving (as I recall, I was interleaved and INP'd) but this current state is not reflected on the service test.

Or it could be something else entirely...
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kitz

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Re: A heads-up - [VCMM line cards change out].
« Reply #19 on: June 03, 2015, 09:48:03 PM »

Further to this, I just stumbled across a BT doc in relation to this when looking for something else.

Quote
EMP2750 CPE Affecting Release Notes - Fixes

ELEM not correctly implemented on VDMF(MA5603T) and VDSH(MA5616) line cards.
DSLAMS report different PSDs when AELEM is activated. Fix corrects this issue
Fix for issue where when AELEM is turned on, the achievable upstream rate drops very
significantly drops on long lines even when there is no bridgetap on the line on all Huawei
DSLAM Linecards.

Note in there the mention of ANFP compliance of Vectoring and also confirmation of the introduction of the MA5611 for Fibre to the Node

Still no MA5611.  But did find a MA5611S which seems to fit 
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