DLM Query

[TerryC]

Hi - some advice please.

My BB unlimited service has consistently delivered downstream speeds of in excess of 7.5 Mbs for over 3 years and since December following another DLM run rose to 9.3 Mbs with an SNR of 6.3dB. Speed nor SNR ever varied. Last week the D/S speed suddenly dropped to 4.1 Mbs yet the SNR remained the same. Sky performed a line test which revealed nothing and on completion it re-synced at 9.3 Mbs again. However after a few minutes it dropped to just over 5 Mbs with a SNR of 17.1 dB. I called them back and after plugging the router into the test socket (I had a filtered faceplate - no extensions, no other boxes connected) with the filter supplied by Sky it connected at 5.6 Mbs after another line test which again revealed no fault. (The line is quiet on a corded phone.) Sky said they would start DLM again which is shown on "My Sky" as starting on the 20th. However, since then I have seen no change in speed but the D/S SNR varies between 6.8 and 15.4 dB - not suddenly but seems to stay in incremental ranges of say 6-8 db 9-11 etc. for a period before going up and then back down. Sky have also said that the speed I am getting is what they would expect on my line (3.5km 48db attenuation) which I'd agree - however having seen consistently higher speeds that would not seem to be the case.

Is this typical of the DLM process i.e change SNR but not speed for a start - I always assumed that it upped the speed incrementally usually around 2 am to see what the optimum error free speed would be. The router is still plugged in the test socket. The upstream speed is .79Mbps which I believe is indicative that DLM is running?


Thanks

Terry

[Isitme]

If the noise margin is fluctuating that much, it looks like you have some sort of intermittent interference on your line. This makes it very difficult for DLM to set a stable speed. Although it may not be showing up in their tests, it is possible there is a fault on your line. You could do worse than run Routerstats Lite for a while and save the results as a graph. This would give you a record of exactly how your noise margin is behaving.
Internet Software

If DLM training is running it should resync your router between 2 and 3 am. If its not, then it is possible DLM training is not actually running.

[TerryC]

@ Isitme - Thanks for your reply. I'm running a MAC so the tool is not an option. However, just watching the router stats over time with a polling rate of 3 secs I see the SNR fluctuate between the values I posted earlier but they're not sudden jumps. The speed doesn't change though, and again last night there was no re-sync so I guess DLM probably isn't running as I think this would try and set the SNR at 3, 6, 9 or 12dB. The Sky call back on Friday for an update/progress check never happened so I'll call them again today and try and get to speak to the CST/EST.

Edit: Sky seeing high error rate yet line test ok so Openreach to look at it.

Edit: REIN issue - see my reply to http://www.skyuser.co.uk/forum/sky-b...pping-out.html

[TerryC]

Turned out to be a REIN issue - see my post in http://www.skyuser.co.uk/forum/sky-b...pping-out.html