Hi, I have posted threads before about disconnections as the downstream SNR margin was low -sometimes 0. This was resolved by "hard coding" the downstream SNR to 9. Not sure if "hard coding" resolved the issue or at some point the thinking was to take the circuit off DLM. Has been OK since then but recently I am seeing lots of retrains again and looking at the router stats, it seems like the upstream margin is now causing the problems - very low at circa 2db. No noise on the line, no change in setup. I'll post some router stats later as I'm off to a christening now.
I've known occasions such as yours whereby DLM finds it difficult to stabilise a connection ... and as you say the lack of noise margin causes the connection to erode, often ending in a hard setting to stabiise it. From my experience such settings can and do work, the downside being they can only be temporarily set to hard figures ... after which the connection defaults to DLM auto/both paths.
Your low snr is causing severe errored second counts and yet the margin doesn't budge ... could be a dslam power problem.
In all reality if the reason for that instability cannot be found, you need help again. Low snr connections can be difficult.
Wait for an invite from a moderator ... your connection needs evaluation.