Have you any hair left now?
Haha.
I didn't have a lot to start with & have even less now
From my logs I noticed the modem had resynced at just after 5:00 this morning.
Sync speed is down to 33.14Mb, IP Profile at 32.07Mb & throughput at 30.14Mb.
speedtest.net result
I can’t see what might have caused the re-sync other than DLM trying different settings until it finds a suitable balance between speed & stability over the first 48 hours.
The 10 day training period does not exist for VDSL2/FTTC connections (despite what ISPs & BT agents might tell us).
I noticed that Interleaving had been turned off for both DS & US, hence the ping time of only 5ms.
I thought that a little strange though as I still see quite a lot of various errors & error seconds.
Interleaving had always been on at varying depths (up to 1700) for my DS & off for US until yesterday.
Following yesterday’s DLM reset & until this morning’s re-sync, DS interleaving was at a depth of 16 & US at a depth of 8.
Now they are both at a depth of 1 & 1 (off).
Impulse Noise Protection is also currently at 0.00 for US & DS, as is delay.
I don’t ever recall seeing that previously for my connection.
I think during the next 24 hours will be when the connection stabilises (according to BT’s SIN 498 document):-
“2.2.5 Dynamic Line Management
Dynamic Line Management (DLM) is employed in GEA-FTTC. DLM constantly manages lines to maintain a target stability. It does this for as long as the product exists.
At provision, the line is put on wide open profiles, allowing downstream line speeds of up to 40Mbit/s, and upstream line speeds of up to 2Mbit/s or 10Mbit/s depending on the upstream product option selected.
On the first day of operation, DLM will intervene if severe instability is detected.
Otherwise, DLM will wait until the day after provision before intervening, provided that the line has been trained up for at least 15 minutes during the preceding day.
If DLM intervenes it will set a capped profile with a maximum rate and a minimum rate, where the minimum rate is set at approximately half of the maximum rate.
The purpose of the minimum rate is to ensure that the line does not train at a rate which is significantly below the level the line should be able to achieve. If this happened, then the line is likely to remain at a very low rate till a re-train is forced by the user powering off the Active NTE.”
The time frame mentioned is rather vague (in days rather than hours), so maybe BT’s day starts at 5:00am?
My modem re-synced in the early hours (around 20 hours after the DLM reset), when SNRM is at its lowest.
Maybe it would have achieved a higher speed if it had re-synced at around 2:00pm, when SNRM is usually at its highest.
I’ll resist the urge to FORCE any re-syncs for the next few days as I really don’t want DLM to think my connection has become unstable again.
Edited by Bald_Eagle1 (Sat 10-Mar-12 09:51:26)