Router resyncs at night

My brother is on this dreaded service and I purchased a Speedtouch 585v6 for him as I have one and they are much better than the homehub in my opinion anyway.

He noticed of late that the router is resyncing at night to a very low level, ie approx 192kbps with a high SNR of 27db, line attenuation is 55db.

If he resyncs the router he usually gets in low 4000kbps back with an SNR of 7-8db.

Is this a form of throttling kicking in, that is BT forcing a resync of the router to an intentionally low sync rate.

He is connected in the master socket using a pre-filtered master socket and has only noticed this issue in the past couple of weeks. I have aksed him to put his Homehub back on the line and see what happens but BT seem to have set a restruction on his connection SNR with the homehub and it wont go lower than 12db as he cant use DMT on it.

He is attached to the Lennoxtown exchange whcih various checkers seem to indicate no issues with, I may be wrong though.

Any ideas??

their is definatley traffic management but it does not force a resynch the hub on latest firmwear has a false snr on it and they stopped us playing with the dmt tool.

The router used by the OP is not a hub but another speedtouch router. It's nothing to do with BT trying to make his line slower it is not possible for BT Retail his ISP to force a re-sync.

Might be a line card issue. I used to have an "fast path" line which got switched to "Interleaved" due to an exchange fault messing with my line sync.

The annoying thing was that whilst it would mostly sync at 1728 and above, a loss in sync would often result in my router (both a Draytek Vigor 2600+ & my current Speedtouch 546v6) trying to resync in "fast path" mode at the old fixed 1Mbit speed (1152 / 288) when it needed to resync in "Interleaved mode" as that was what the DSLAM in the exchange said I needed.

Anyhow, knowing how useless the offshore tech support is / was I left it and after a period of 3 ~ 4 months the issue went away after a long period of no sync.

Changed ISPs & asked them to reenable "fast path" as I knew my line handled it before the exchange fault, & have no troubles now.

If you can, see what mode your router is in when it's syncing correctly and what mode it is in when you get a bad sync.

As luck would have it the fault that I had meant that even though I had sync I had no 'actual' internet connection, so I was never forced onto the 1Mbit profile, it was just the hassle of having to do 4 ~ 8 reboots to get a working connection again.

This sounds more like a noise issue (evident because it goes back up to 4000kbps + when he reboots).
Can you get him to install DMT v7.23 on his PC, and use it to graph the noise margin (SNR) - it can do that with a 2 second interval between samples?
That way, you'll be able to see if the SNR takes a sudden nose-dive just before one of the low re-sync events.

It could be something as simple as a plasma TV, or boiler firing.

Thanks for the advice guys, much appreciated.

I have DMT 7.32 installed on his system with the automatic dsl monitoring switched on and taking a reading every 5 minutes. I also increases the target noice margin, so I have left him with a sunc of 4064kbps and an SNR of 8db, told him to leave PC on to monitor this for thenext day or so if possible to build up some clue as to what is going on.

I'll let you know.