This is a discussion on DLM Query within the Sky Broadband help forums, part of the Sky Broadband help and support category; Hi - some advice please. My BB unlimited service has consistently delivered downstream speeds of in excess of 7.5 Mbs ...
- 23-02-14, 09:44 AM #1
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?
- 23-02-14, 02:31 PM #2
Re: DLM Query
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.
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.
- 24-02-14, 08:43 AM #3
Re: DLM Query
@ 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 Noisy Phone line (broadband dropping out)
Last edited by TerryC; 04-03-14 at 10:15 AM.
- 04-03-14, 10:16 AM #4
Re: DLM Query
Turned out to be a REIN issue - see my post in Noisy Phone line (broadband dropping out)
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