FTTC uses OpenReach's DLM, not BT Wholesale's, and it's a lot more end-user friendly.

I agree that the FTTC DLM is less bad than the old ADSL DLM was.

and takes effect immediately.

Not true. As I said above, it takes effect immediately on pppoe connection. However, the pppoe reconnection does not necessarily happen immediately. Where it does not happen immediately, it could easily be deferred for weeks or even months.

In reply to a post by StephenTodd:

Not true. As I said above, it takes effect immediately on pppoe connection. However, the pppoe reconnection does not necessarily happen immediately. Where it does not happen immediately, it could easily be deferred for weeks or even months.

You may be right, but as I've never had a re-sync without a corresponding loss of PPPoE I can't comment.

I've never had a re-sync without a corresponding loss of PPPoE

I have had a few.

When there is a significant issue causing immediate loss of sync (and often an immediate degradation of DLM profile), the pppeo connection may well be in active use, and also the overall incident usually takes long enough that pppoe connection drops. However, where DLM permits a scheduled sync speed increase (2:00 am for me) after a period of stability, my experience (maybe only 4 or 5 times, so not very extensive) is that pppoe connection is not usually dropped.

As I said above, reconnecting the router can never do any harm. If you do not have an unlocked modem, there is no way to tell whether you are in the situation of an IP profile that does not match the sync speed (subject to the 96% or whatever it is ratio). That is why I suggest regular router reconnection if expecting a sync increase.

he is correct. the ip profile is set on the pppoe connection success.

I must admit I didn't realise that an IP profile update only happened at PPPoE time and not on a re-sync.

In my defence, as I've never had the the second with the first there's no way I'd have found out

I agree, it doesn't do any harm to reboot the router now and then- if nothing else it gives the system tables etc a good clear-out

In reply to a post by billford:

I must admit I didn't realise that an IP profile update only happened at PPPoE time and not on a re-sync.

This has been the norm for me, I don't think my profile has ever updated automatically following a re-sync, I've had to force a reconnect to get it to change.

In reply to a post by billford:

FTTC uses OpenReach's DLM, not BT Wholesale's, and it's a lot more end-user friendly.

The IP Profile is actually set by the WBC DLM, Bill. The rest of it, noise margins and so on, are down to the Openreach one, though I'm not sure WBC DLM doesn't occasionally stick its oar in regarding the stability option.

The Openreach DLM sends out a notification on establishment of a PPP session, not on synchronisation. WBC picks that up and adjusts the IP Profile immediately. 96.79%.

As has been sort of described, the failure to adjust it happens when the modem re-sync's and re-establishes the connection before the CP drops the session. (This also happens occasionally on ADSLx - IPs seeing a constantly connected line where the modem/router log shows re-sync's).

I'm fairly sure this is what has been causing the OP so much confusion. He says the modem connection has been rock solid, but I have grave doubts about that. Then when he does anything with the router he gets the correct IP Profile.

Edited by RobertoS (Tue 12-Feb-13 13:24:26)

some of us have configured high ppp timeouts so if a unplanned resync occurs on a isp with dynamic ip then the ip is maintained.

The sideeffect is tho the ip profile isnt updated,

In reply to a post by RobertoS:

The IP Profile is actually set by the WBC DLM, Bill. The rest of it, noise margins and so on, are down to the Openreach one, though I'm not sure WBC DLM doesn't occasionally stick its oar in regarding the stability option.

Ah right... I can see where my misunderstanding was coming from.

Strictly¹ speaking, the IP profile isn't part of the line management, although it responds to it. It's really connection management, like the 40 or 80 Mbps options. I'd been assuming they were all lumped in together.



¹ Pedantically, if you prefer

Strictly speaking, the IP profile isn't part of the line management, although it responds to it.

Absolutely. It causes quite a lot of confusion. Almost always when people say they have a stuck profile, it is DLM doing its job (maybe slightly overzealously).

There do seem to be fairly rare cases (which I don't understand) where the IP/BRAS profile really does get stuck even when the sync speed has gone up and the pppoe is reestablished.