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I like the new DSLAM, everything else is a disasppointment.

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Lorian
Grafter
Posts: 701
Registered: ‎31-07-2007

I like the new DSLAM, everything else is a disasppointment.

OLD Situation:
I have a notoriously bad line. priort to 21CN the average 8am stats would show:
28500/448 Sync @ around 8db (traget SNR was 6gb). Interleaving on. Draytek Vigor 2700 router, latest firmware.
It should be also note I have a good faceplate filter, no ring wire, and I've done an RF sweep of the place etc.
The line is old, lots of it on pole, and the attenuation wavers a little around 54db.
Error rates average at about 80 and hour over a few days.
SNR wanders down about 3db overnight.
NEW Situation:
Won't Sync at ADSL2+ at all(tried 3 routers inc plusnet one)
ADSL2 Syncs at around 3.4Mb but SNR soon tails off with quite high error rates.
57db attenuation reported.
Using ADSL (g.DMT) however is very good compared to on the old DSLAM:
Syncs at around 3.4Mb/sec and just stays there.
SNR only wanders down maybe 1.5db over night
Error rates down to about 100 a DAY (maybe helped by my rouer having an infineon chipset like the DSLAM)
up sync a little disappointing at around 600Kbps. (use to get 800K on the premium trial)
Attenuation down to 52db
So suprisingly a usefull gain and a notch up on the BRAS data rate even though I'm still using G.DMT.
Still a bit disappointing though. Guess I'll have to move.
2 REPLIES 2
Superuser
Superuser
Posts: 10,004
Thanks: 1,335
Fixes: 71
Registered: ‎06-04-2007

Re: I like the new DSLAM, everything else is a disasppointment.

With your attenuation downstream benefits from ADSL2 are expected to be small, as you found. It's interesting that using G.DMT gives lower error rates.
What is your upstream noise margin? Others have found leaving the connection alone (for up to a fortnight) can help the DLM/MSAN get the best out of the line.
David
David
Lorian
Grafter
Posts: 701
Registered: ‎31-07-2007

Re: I like the new DSLAM, everything else is a disasppointment.

US noise margin was 12db last time I looked. Maybe it adapts automatically on the 21CN platform, in which case there is some hope for it.
I'm not planning on playing with it for a while and see what happens.
I had been hopping ADSL2+ might have bought me a few 100'Kbps using single-bit encoding bins, enough to bump me up anothee BRAs step, but heh its a bit better so I'm not going to look the gift hourse in the mouth.