I think my lift and shift has actually made a small improvement. The new DSLAM port seems to be relatively gentle, starting sync was 4320 day 1, at 6dB and IP profile 3000, post 3 pm noise started to increase as per usual and had three downward resync's, but very small 3968,3776,3680. Left it on overnight, as per Roseways suggestion, and the 3680 held which is good as my noise issue doesn't usually improve until around 7.30am. IP profile held at 3000. Prior to the lift and shift on a good day I would have an IP profile of 1500, but I used to get savage cuts on resync, usual sync was 2300 and this would resync to 900-1000 with IP profile usually going down to 750-500K or even 250K (for 3 days) if there was another resync. I assume this was because my target margin was 15dB, so clawing back from -4dB (when my connection drops) forces big drops in sync speed. If that is right it is a big disadvantage with high target SNR margins, if they do get breached you will get hammered.
Day 2 had one small resync upwards to 3744, followed by a resync down to 3712 in the post 3pm period. Then back to reality, sudden drop, resync at 2464, so much for the gentle DSLAM, IP profile dropped to 2000, still it's better than what I used to get. Turned the router off at night.
Day 3 seems to be following pattern of Day 1 - starting sync 3968, followed by two small adjustments to 3776 and 3744 during the noisy period, IP profile still at 2000.
As my interleaving was switched off by the lift and shift I am seeing CRC errors, which I don't know how to interpret. The router seems to cumulate errors until a resync, then starts again. I have no idea at what level CRC errors should become a concern - how many a minute. Can anyone help me on this. I've asked for interleaving to be turned back on but that will take a few days.
Overall it is an improvement, the instability post 3 pm it is still there but the effects are not quite as severe. Whether it remains this way only time will tell. Overall I'm surprised by the very small reduction in sync after a drop (generally drops occur below -4dB). Have attached router stats for day 1&2 - the red blobs are disconnects
Bought one of the £11 Speedtouch 510v6 off Ebay, will give that a go when it arrives. Hopefully it will not join the pile of modems, routers, card readers, CPU's, memory cards, and general antique and next to worthless electronica which fill one cupboard. If it doesn't work I'll try for an Engineer who has some specialist understanding of the process - not holding my breath though.
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