cancel
Showing results for 
Search instead for 
Did you mean: 

FTTC dlm guide and barrier

Community Veteran
Posts: 1,990
Thanks: 5
Registered: ‎11-12-2013

FTTC dlm guide and barrier

Thanks to Chris for this guide.  http://community.plus.net/library/browsing/fttc-dlm-what-it-is-how-it-works/
The question is can we get the barrier information made available in our control panel?
Ideally line green or red status as well.
20 REPLIES
goldenfibre
Pro
Posts: 2,858
Thanks: 89
Fixes: 6
Registered: ‎01-06-2010

Re: FTTC dlm guide and barrier

^^ +1 I agree as these are useful and I hope it will available on the control panel member one day.
xxandy77xx
Grafter
Posts: 126
Registered: ‎21-09-2013

Re: FTTC dlm guide and barrier

Thanks for the guide chris.
I have a question about DLM might sound silly but  here goes.
Ok take my line for instance,  been great for over 30 old days  have had no problems  best its been  syncing at 74  and now  cause some machine thinks i have a problem or had a problem  its starts disconnecting me and knocks my speed down, doubles my ping  and whatever else it does.
Now surely if there was or  had been a problem i would of noticed  this, by loosing connection  or surfing problems/ gaming  etc etc... .
So why cant it just leave it alone till there`s been  i don`t know major problem or whatever , because i havn`t  seen/noticed any problems,  now am no  expert  long way off  but to me there`s been nothing wrong here.
Yes i know it`s there  to keep your line  up and running and stable  if people have problems,  but it just so annoying  if everything thing seems fine and then starts messing on  that`s how i see it anyway .
Ok think i got my question/point  out  hope it doesn`t sound silly Smiley
Thanks
Andy.....
Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: ‎26-11-2011

Re: FTTC dlm guide and barrier

I'm glad you've found the guide useful Smiley
@chrcoluk & goldenfibre - When we get access to this information from our suppliers (something that they're working on) it's something that we'll look at - I can promise that it'll be something we can provide as it's only something that will be displayed when we run a Line Test. we'll certainly consider this though Smiley
@xxandy77xx - The disconnections you've experienced either yesterday or Saturday as shown below are the probably reasons for your speed drop:
<img src="http://community.plus.net/visualradius/generated/image14011772164831.png"/>
The line has probably seen a large burst of errors, more than the line can handle, and as a result, it looks as though the connection has dropped a few times. Interleaving has been switched to High to handle the errors that were visible on your line. In this instance, it looks as though DLM has acted to stabilise your line in this case.
Chris Pettitt
Cloud Environments Engineer
xxandy77xx
Grafter
Posts: 126
Registered: ‎21-09-2013

Re: FTTC dlm guide and barrier

Hi chris,
Thanks for the graph,  now this is the part i don`t understand,    because dlm had already kicked  in last week  before any of those on sunday  and i had no disconnections no problems or any thing  apart from last wednesday early morning ,  then speeds started to drop  from there. So to me its acted with no reason at all,  but obviously its done it for a reason  but  i`ve been online over 30 days  i left everything alone everything was perfect  then its goes and mucks things up. Hope you understand what i mean lol .
Thanks
Andy.....
Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: ‎26-11-2011

Re: FTTC dlm guide and barrier

Hi Andy,
DLM kicks in overnight, generally between 3am-5am, that's when it makes changes. You might not notice the drop on the graphing as the drop is very quick. If the DLM monitoring notices a whole bunch or errors at 5pm for 15 minutes, it'll take that into consideration when it decides what action to take on your line.
A really important point, DLM doesn't just detect how long you've been online for, it looks at the errors on the line and takes action to stop them from getting higher and higher and eventually causing you to drop connection or the connection becoming unusable.
Chris Pettitt
Cloud Environments Engineer
Community Veteran
Posts: 6,824
Thanks: 1
Registered: ‎27-10-2012

Re: FTTC dlm guide and barrier

Are there not situations where DLM works with immediate effect, particularly if someone is seeing a large number of disconnects in a short period?
Say someone is watching the World Cup final via Multicast and there are a large number of errors causing disconnects during the game, it seems strange that DLM will have to wait until the next morning to provide line stability.
Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: ‎26-11-2011

Re: FTTC dlm guide and barrier

Unfortunately not, it doesn't work on the fly like is does for ADSL.
There are ongoing discussions at the moment with regards to a DLM re-design for FTTC but we've not got anything set in concrete on that yet.
Chris Pettitt
Cloud Environments Engineer
goldenfibre
Pro
Posts: 2,858
Thanks: 89
Fixes: 6
Registered: ‎01-06-2010

Re: FTTC dlm guide and barrier

Hi Chris, interesting things about DLM errors check on the line. Can you ran a quick test and sent me via tickets and also enclosed how long I been connection since FTTC went live last February 2014. I like to know how many errors on my line so far. I ran BT speedtest and the ip profile stay the same as last February, no change. Still getting 74/18. Smiley Thanks.

Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: ‎26-11-2011

Re: FTTC dlm guide and barrier

We don't get a great deal of information at the moment, I can provide a 15 minute snapshot of how your line has performed, however if your profiles are still looking fine, you shouldn't need any stats posting really Tongue
Chris Pettitt
Cloud Environments Engineer
Community Veteran
Posts: 1,990
Thanks: 5
Registered: ‎11-12-2013

Re: FTTC dlm guide and barrier

Chris if there is a redesign under consideration here is my suggestions.
Add a overide system, enforcing full automation on everyone isnt right and ultimately will add support load anyway as you know people demand fast path back etc.  At the very least make it so isp's (and in turn even end users maybe) can initiate a DLM reset.
The current system where DLM reacts hours after the event is silly, e.g. if a line has a burst of noise at 7pm, whilst the user is watching netflix its a one off burst of noise that lasts an hour, the netflix experience is ruined due to excessive errors on the line, but DLM doesnt react until 5am the next day when its too late, and then the line is interleaved/throttled for 8/15/31 days because of a one off burst of noise.  Thats bad.
I have been using my service at 5am, everything is fine and DLM knocks me offline to make a change.  Not good.  I dont think DLM should ever take a line offline to make a change, it should only make a change if the line is offline anyway or actually during periods of instability, not hours later.
So in short share info, give user's (or at least isps) some control, and make DLM more passive including an overide system.
Community Veteran
Posts: 6,824
Thanks: 1
Registered: ‎27-10-2012

Re: FTTC dlm guide and barrier

I would think that if DLM is going to reduce your sync speed, it will have to drop your connection no? Perhaps if it worked on the fly like ADSL, then it wouldn't be as much as an issue.
Stability needs to be instantaneous (for those that want and need it), rather than delayed. I would think anyone using IPTV/Multicast would want prioritised and stable TV service.
Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: ‎26-11-2011

Re: FTTC dlm guide and barrier

@chrcoluk - I'l certainly take your comments on board. Whatever changes do come to fruition, need to be right for the End User and right for each Communications Provider. I don't think what you've asked for is unreasonable either. I have already put forward, as have other ISP's, what our requirements are, but I think it's going to be a fairly lengthy process as it's going to require investment and development.
@AndyH - Yes, if it worked on the fly, it would be great, something that I feel may be looked at. I agree with what you say and I'll pass those comments on when I next meet BT Openreach tomorrow.
Chris Pettitt
Cloud Environments Engineer
leader
Grafter
Posts: 261
Registered: ‎02-02-2013

Re: FTTC dlm guide and barrier

Thanks chris
Which set error rates is the dlm using for its "intelligent decision" making..... ?    {The ECI  msan's report certain error rates differently to Huawei's}
Thx  Smiley
x47c
Grafter
Posts: 878
Thanks: 1
Registered: ‎14-08-2009

Re: FTTC dlm guide and barrier

Quote from: chrcoluk
Add a overide system, enforcing full automation on everyone isnt right and ultimately will add support load anyway as you know people demand fast path back etc.  At the very least make it so isp's (and in turn even end users maybe) can initiate a DLM reset.

I suspect BTOR will be very reluctant to give anyone control of Interleaving.
If/when vectoring comes into play then the DLM/vectoring stuff needs to be in complete control of the network.
Any outside ability to unilaterally affect one line  by switching its parameters - which may have the effect of messing up everyone else's line in the vectored cable bundle is going to be highly undesirable.
Mind you the same applies to those who remove the BTOR modem and put another 3rd part modem in its place.  If this modem has a less than effective vectoring compliant routines running in it then it has the ability to again mess up the vectoring of other lines in the cable bundle.  The ultimate solution is of course for the DLM simply to disconnect the disturbing modem!
We are indeed moving towards a fully automatic system with no overrides.
The nearest analogy I can find are car ignition advance/retard system.
Originally a lever on the steering wheel controlled them and the driver set it for the engine load conditions.
Then various springs and manually adjustable offsets in the distributor made a semi-bad job of automating it.
Now it is done totally invisibly by the engine ECU and there is no way of altering it.