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[Dave2150]

Hi there,

I saw that my downloads were going much slower today, checked Mydslwebstats to find that my modem has decided to adopt a 9DB SNR and this has resulted in a 26mbit sync, whereas my line is usually very stable at 31-32Mbit. (My line was syncing at 35-36Mbit stable when G.INP was enabled a few months ago).

I'm wondering whats caused this? I see there have been a few ES over the last few days - which is quite uncommon for my line, but would this be enough errors to warranty a 6Mbit loss of DS speed? Note that I didn't notice any lag/slowdown on the line at all lately.

Or perhaps this is banding? I had to get an engineer out to reset the banding last time, hopefully I don't have to go through that nonsense again.

Many thanks for any help.

[NewtronStar]

Another manual resync of the modem should cure your issue, I can see you turn off the FTTC modem when you go to bed it's not something myself would do on FTTC yet it was ok in the ADSL days.

[Chrysalis]

My gut guess the line is not banded, check on july 19th and you see the snrm swung downwards, so I am going to guess when you last synced up, it was when the snrm had swung down, and then after sync it increased (seems very shortly after) and this is showing as excess snrm.  The sync speed also suggests you not banded.

In short I agree with newt's advice.

[Dave2150]

Thanks guys, I'll give it a restart later on once it's not in use.

I also noticed my interleaving depth reduced from ~600 to 500, I wonder if this has any bearing on it?

[NewtronStar]

When my own line had Interleaving the depth would change every time the modem was resynced sometimes with a slightly low depth and then higher depth and did see a pattern when the modem sync rate was higher the INT: value was larger and lower sync rate the INT: value was lower

[WWWombat]

I'm wondering whats caused this? I see there have been a few ES over the last few days - which is quite uncommon for my line, but would this be enough errors to warranty a 6Mbit loss of DS speed?

It doesn't look like banding, and the small set of SNRM stats (from 06:58 to 07:10) suggest that some noise disappeared in precisely this period. As it looks like the resync happened at 06:49-06:50 and other stats are missing from this instant, I'd guess that there was some noise event at the time that caused a loss of sync; the noise stayed long enough to cause a reduced speed at the new sync; and the noise went at 07:04.

There's little sign of errors each day; I'm not sure whether we should see a burst of errors when you turn monitoring back on, so can't really tell what happened at 06:49.

I also noticed my interleaving depth reduced from ~600 to 500, I wonder if this has any bearing on it?

I think the interleaving depth adjusts to suit other aspects (such as speed), rather than being a cause. The more significant parameters are the "INP" and "delay" parameters, set by DLM, but those haven't changed at all.

[Dave2150]

My line synced this morning at 30.7Mbit - not quite back to the usual numbers but almost there. Phew - I thought I might had been banded again.

I'm still trying to figure out what could have caused such a large noise spike yesterday morning - I've ruled out every electronic appliance in my house, as they are used everyday etc, so the noise source must have been external. Fingers crossed I don't encounter it again!

Many thanks to those who helped