General Discussion
  >> Fibre Broadband


Register (or login) on our website and you will not see this ad.


Pages in this thread: 1 | 2 | (show all)   Print Thread
Standard User ffox
(committed) Wed 11-Mar-15 10:36:22
Print Post

Classic DLM?


[link to this post]
 
I've had a rock solid FTTC connection for 4 years. For the last 3 years the download speed was about 73 Mbps and ping was averaging 15ms. The BQM looked almost clean apart from ping spikes in the evening peak hours.

In the early hours today something happened. The BQM showed a packet loss spike of short duration following which the average ping increased to 25 ms. Speedtests now show 66 Mbps.

I suspect DLM has kicked in and put interleaving on. I gather it will take at least 9 days of stability before it is removed.

Not complaining, but what could have caused insufficient instability for this to happen so quickly?

Plusnet Unlimited Fibre Technicolor TG582n , St Ives Cambs (EMSTIVE)
Standard User ian72
(eat-sleep-adslguide) Wed 11-Mar-15 12:03:34
Print Post

Re: Classic DLM?


[re: ffox] [link to this post]
 
Mine has done that a couple of times. No visible noise issue - it just decided it needed to turn on interleaving. Both times it took about a month for it to decide to turn it back off again.
Standard User Al1264
(member) Thu 12-Mar-15 09:19:42
Print Post

Re: Classic DLM?


[re: ffox] [link to this post]
 
Mine just went back to fastpath a couple of days ago...

...after very roughly a year on interleaved.


Register (or login) on our website and you will not see this ad.

Standard User WWWombat
(knowledge is power) Thu 12-Mar-15 13:37:44
Print Post

Re: Classic DLM?


[re: ffox] [link to this post]
 
In reply to a post by ffox:
Not complaining, but what could have caused insufficient instability for this to happen so quickly?


So quickly? I'm not sure that 4 years counts as quick.

The answer is likely to be crosstalk - which is noise cause by the signal of other FTTC subscribers. VDSL2 is very susceptible to this, potentially losing up to half of your theoretical speed.

The extra noise from crosstalk normally manifests itself in two ways, with a consequential third.

1) The increased noise makes for a decreased SNR - so reducing the maximum attainable speed on your line. For those over 80Mbps, this happens (mostly) invisibly for a while. For those with lines longer than, say, 200-300m, crosstalk can become enough for speeds to drop below 80Mbps.

2) Increases in noise also come with increases in the errors (visible as the count of CRCs), and therefore the average error rate (visible as the ES count over 24 hours). Such errors become glitches on streamed video and audio, or triggers re-transmission of parts of download - which also acts as an intrinsic method for slowing down the TCP protocol. This means downloads are slowed down.

In some cases, packet loss can be seen in a BQM, but smart router queuing mechanisms can mean that packet loss gets focussed on TCP rather than the UDP used by the firebrick. This means slowdowns would not be so visible on a BQM.

3) When the error levels in (2) reach a sufficient threshold, DLM kicks in. It is likely to have been a one-off, at first, so will recover. Over time, the error rate would increase to breach the threshold more often until, eventually, DLM stays triggered.

4 years is plenty of time for take-up to increase, and for you to have been experiencing all 3 of these issues.

With luck, G.INP will be around soon to reduce the impact of DLM intervention. And with more luck, vectoring will arrive eventually so that the error rate drops and the attainable speed is restored.
Standard User WWWombat
(knowledge is power) Thu 12-Mar-15 13:38:19
Print Post

Re: Classic DLM?


[re: Al1264] [link to this post]
 
In reply to a post by Al1264:
Mine just went back to fastpath a couple of days ago...

...after very roughly a year on interleaved.


Perhaps you've been changed over to a G.INP profile.
Standard User ffox
(committed) Mon 30-Mar-15 21:24:03
Print Post

Re: Classic DLM?


[re: WWWombat] [link to this post]
 
It looks as though G.INP tried to get in and failed, with DLM putting interleaving on as a result. I've updated the HG612 software and now G.INP is on and speeds/sync are back to normal.

I think the info below posted by Realalemadrid should be publicised more. I wasted a lot of time trying to update via the GUI!

I don't think you can use the web gui to update the firmware, it doesn't work! You basically have to do the same steps as for unlocking the modem but load the latest (08) firmware.


Plusnet Unlimited Fibre Technicolor TG582n , St Ives Cambs (EMSTIVE)
Standard User mlmclaren
(experienced) Tue 31-Mar-15 00:30:39
Print Post

Re: Classic DLM?


[re: ffox] [link to this post]
 
G.INP...

Happened to me... Happening to many others...

Surprised you haven't come across a post...

Hang in their, I'm sure it will be fixed some time this week...

Hopefully smile

Plusnet Unlimited 21CN 4200/800 @ 4.2Km > TP-Link TD-W8968v3 - BQM IPv4
Plusnet Fibre Extra 66000/20000 @ 450m > HG612 (Unlocked) > Linksys LRT224 - BQM IPv4
Standard User adslmax
(knowledge is power) Tue 31-Mar-15 00:38:28
Print Post

Re: Classic DLM?


[re: mlmclaren] [link to this post]
 
Will G.INP ever put us on fast path one day like turned off interleaving? Mine is G.INP interleaving at (D: 16/8) INP: 47.00 / 48.00

Edited by adslmax (Tue 31-Mar-15 00:39:46)

Standard User mlmclaren
(experienced) Tue 31-Mar-15 00:42:47
Print Post

Re: Classic DLM?


[re: adslmax] [link to this post]
 
what is the ping on your BQM at the moment...

I'm back to stead 11ms and G.INP has my line on 8 each way currently...

I can't be sure what it changes things too but I know that the interleaving don't seem as vigorous (if you like) as the previous system..

I assume that it is possible to go back onto fast path, but I like many other can't be sure yet...

Plusnet Unlimited 21CN 4200/800 @ 4.2Km > TP-Link TD-W8968v3 - BQM IPv4
Plusnet Fibre Extra 66000/20000 @ 450m > HG612 (Unlocked) > Linksys LRT224 - BQM IPv4
Standard User adslmax
(knowledge is power) Tue 31-Mar-15 00:51:49
Print Post

Re: Classic DLM?


[re: mlmclaren] [link to this post]
 
Here is mine LIVE BQM: http://www.thinkbroadband.com/ping/share/ab9db71b318...
Pages in this thread: 1 | 2 | (show all)   Print Thread

Jump to