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[michty_me]

Morning all,

Just a query regarding the way DLM implements itself. I've noticed a lot of resyncing going on on my line lately and it appears that it knocks a couple of Mb off my upstream sync then adds it back a few days later.
A couple of months back I had a BT engineer out as my sync speed went from 74/19 to 17/??. It mostly came back on its own but wouldn't budge past 49MbD/S speeds. They checked the line and swapped me to a Mk4 filter then reset the line to an open profile. It appears that It won't sync past 70Mb now so I assume someone may be crosstalking with my line now.

My line had been solid for around 3.5 years with no change.
Any thoughts? My stats should be available on MDWS if required.

[kitz]

knocks a couple of Mb off my upstream sync then adds it back a few days later.

This behaviour isnt uncommon and Ive seen it occur on several lines - including my own - for quite a while.   
It usually correlates with a change in power profile rather than anything to do with DLM.

Openreach are using DSM to manage power which can help reduce crosstalk.  Profile given depends upon the number and the line lengths of neighbouring lines. 
The power profile will affect your SNRM, which in turn affects max sync. 

[michty_me]

Thanks for the explanation on what may be happening. It has only recently started occurring to be honest so I've just been curious as to what may have been the cause of it.
Prior to this happening, My line hadn't budged in a negative way in over 2.5 years. Nothing that can be done about it but interesting to find out that DSM is also a factor on how a line performs.

[colin79666]

Yep I've also experienced this. All fine for 3 years then towards the end of last year I got a cross talker and download sync dropped from 78ish to 63 with a couple of Mb/s off the upload. I can tell when their modem drops and when they re-sync as my attainable rate shoots back up when they go offline 

[michty_me]

My issue must be with power management as suggested by Kitz. I wonder if another user has come online recently and knocked this all to pot from where it was sitting happy for quite some time. Hopefully it stabilises itself.

[kitz]

I had the benefit of MDWS at the time, which enabled me to see that it was power management rather than a specific cross-talker.

It shows how much easier MDWS made our lives when it came to diagnostics.  Normally we would have assumed it was the direct result of a cross-talker coming on or off line... but in this case I could see a direct correlation between SNRM and power, rather than just SNRM.