Understanding IP profile and DLM ? How long before changes

Hi

I've had FTTC with plusnet for around 5 months now, from day 1 till the end of May it never disconnected once and my IP profile was 77.xx/20mbit (max?), engineer who installed it said the line was capable of 89/44.

However last week i had 3-4 disconnects over 2 days, no idea why, but now its set my ip profile to 70.2/20mbit from looking at BT wholesale speedtest.

Anyway how long before my Ip profile will increase and how can I tell when it has and when is best time to resync without making DLM kick in ? : )

PS still think DLM is a stupid idea ! after spending years with UKonline and Be there who let you set your own profiles at your own risk via web app or hacked router firmware.

Thanks

Edited by snoz (Sun 23-Jun-13 22:24:34)

Have you done a manual reconnection of the modem since? It could be simply that whatever happened left you with a low connection speed. The best time to do one is well inside daylight hours, and turn it off for a couple of minutes.

If that doesn't improve things, (only do it once), it could be that the disconnections caused Interleaving to be applied. Has your ping gone up? If so, there is a high chance everything will auto-correct in a couple of weeks or so.

However it's also possible the disconnects happened when other users were being connected at the cabinet and that their ongoing presence is causing crosstalk on your line. If that's what it is, it's tough luck for the immediate future, though Openreach are looking at a cure (vectoring).

For info - there's little wrong with the Openreach DLM that is controlling your line. Sitting above it is a modified version of the BT Wholesale one that controls ADSLx connections, but all it seems to do on FTTC is set the IP Profile. (The Openreach one doesn't have IP Profile). The IP Profile adjusts immediately after a re-sync, and is set at 96.79% of the sync speed. So isn't really an issue.

Where there is an issue is on unstable lines, as PlusNet hold a copy of the IP Profile. That gets out of step quite often and has been a PITA on ADSLx and now on FTTC.

Thanks for well written reply.

So a manual reconnection won't make DLM kick in and change the profile again ? I know its better to do it in day as for some reason ( street lights? ) line stats are worse at night , remember this from my BEthere days trying to get best possible sync. My ping has increased but I opened a ticket with plusnet and they showed me the following :

Sync Status In Sync
Downstream Speed 72.5 Mbps
Upstream Speed 20.0 Mbps
Appointment Required N
Fault Target Fix Time
Fault Report Advised Y
Profile Name 0.128M-80M Downstream, Interleaving Off - 0.128M-20M Upstream, Interleaving Off
Time Stamp NA

So interleaving is off apparently.

Hope they move forward with vectoring asap, I know thye are trailing it atm. I read about that some months ago, I was hoping it would lead to faster speeds, but I guess thats not coming soon as anything above 100mbit will require new routers for everyone.


Actually reading this again i'm already on the max profile ( Profile Name 0.128M-80M Downstream, Interleaving Off - 0.128M-20M Upstream, Interleaving Off) ? So i simple reconnection in the day should increase my line speed again ? I thought when it said on btwholesale test my ip profile was 70.12mbit that was the max my line will sync at no matter what .

Edited by snoz (Sun 23-Jun-13 22:44:38)

Line Profile, as in that data, is not the same thing as IP Profile. BT love to make things confusing.

Line Profile is to do with the way Openreach currently have your connection set up, the major determinant being the product you are on and the minor one being anything their DLM has done to it, such as interleaving (it seems) and banding.

IP Profile is a direct result of the sync speed. Not the other way round. The BTW speed test is saying the IP Profile is the highest throughput you will get, no matter what, so long as that IP Profile is at that value.

So ip profile means nothing it just the sync speed minus the dsl overhead ? Lne profile is the important one, and DLM will only change interleaving levels on this ? What is banding ?

Thanks again

Sort of .

Banding is a feature of DLM that is used by Openreach instead of playing with SNRM levels in the way the BT Wholesale do on ADSLx. (Although IIRC the BTW one can apply banding on ADSLx).

It caps the sync speed to below what the modems think is usable, when the modem-determined speed is consistently unstable. It also sets the minimum sync to about half the cap.

See this table. It looks to me as though there is a typo where yours goes. (IIRC they call that an Open Profile).

Edited by RobertoS (Sun 23-Jun-13 23:27:36)

Ok thanks, Is there anyway to see what if any banding has been applied ?

In reply to a post by snoz:

Ok thanks, Is there anyway to see what if any banding has been applied ?

the plusnet thing shows you on the wide open one, if it were banded it would say one of the lines from the table RobertoS linked too.

on any other BTw isp its instant providing a new ppp session is started. But plusnet seem stuck in the 20cn days where its ok to have a laggy profile system to catch up.

Also DLM and the ip profile are 2 seperate things, DLM doesnt control the ip profile.

Edited by Chrysalis (Tue 25-Jun-13 07:35:01)