Fttc "Stuck" session.

Fttc went down at about 13:45 this afternoon, got back to find that sync was fine but no PPP.

Spoke to P/N support who claims they see me online and it's a stuck session, said it needs to be left out of Sync for an hour for the DLSAM/MSAN to notice and clear it.

Is this likely to be the case, whilst I'm sure a session can get stuck it strikes me as odd that they can't simply kill it from their end and that it would take the DSLAM/MSAN 1hr of being out of sync for it to notice.

Thankfully I have a backup ADSL2+ line with Pulse8 so i'm still online.

Recall this from the early days of the ADSL roll-outs but don't recall this happening on FTTC ever

If you have open reach modem plus a router, have you tried turning both off for a few seconds and back on.

Yes...

Even tried a different HG612 incase it was something to do with my unlocked one.

Tried rebooting the router (Even though pretty sure it didn't need it, Its quite happily authing to pulse8/TT on the other port/PPPoE1)

Router is an ER-X

/var/log/messages was showing Timeouts waiting for pad0 packets

Sounds like garbage. PPPoE sessions are surely under the ISP control, as you think.

Maybe whoever you spoke to isn't high enough to be able to kill it.

In reply to a post by RobertoS:

Sounds like garbage. PPPoE sessions are surely under the ISP control, as you think.

Maybe whoever you spoke to isn't high enough to be able to kill it.

I'm not totally unconvinced that something isn't up with the FTTC MSAN as i tried changing the username to bt_test@startup_domain and couldn't get a PPP session up to that either.

Edit:

Called them back they killed the stuck session from their end and it came up straight away.
Edit2:

Looking into this further it looks like it's an option available to the ISP in the BTwholesale self service toolset.

https://www.btwholesale.com/assets/documents/knowled...

Edited by dragon2611 (Tue 25-Aug-15 21:40:36)

In reply to a post by dragon2611:

I'm not totally unconvinced that something isn't up with the FTTC MSAN as i tried changing the username to bt_test@startup_domain and couldn't get a PPP session up to that either.

Because the PPPoE session with Plusnet was active.

Edit:

Called them back they killed the stuck session from their end and it came up straight away.
Edit2:

Looking into this further it looks like it's an option available to the ISP in the BTwholesale self service toolset.

https://www.btwholesale.com/assets/documents/knowled...

Quite.

Edited by RobertoS (Tue 25-Aug-15 22:07:29)

In reply to a post by MrSaffron:

Recall this from the early days of the ADSL roll-outs but don't recall this happening on FTTC ever

If you have open reach modem plus a router, have you tried turning both off for a few seconds and back on.

Sorry, it's a bit unclear what you meant here, and I'm sorry but that is poor advice as well.
Stuck sessions have not been uncommon on Plusnet including FTTC especially when the was a lot of network issues last Summer/Autumn, and they still do happen if the PPP is lost due to some ungraceful event anywhere between the user and Plusnet.

In some cases on FTTC, logging into the Router and clicking Disconnect for the PPP Internet session and then switching it off for a minimum of 10 minutes will sometimes clear the stale session.

Clicking Disconnect and powering off the Router should be done before even contemplating turning off the Modem - a reboot will do nothing to help clear any stale/stuck sessions.
If anyone is going to turn off their Modem, it should be turned off for at the very least 30 minutes and preferably a hour to ensure the sync loss doesn't get counted as a drop in connection and it resets some of the DLM counters. But it any event I'm not certain that turning off the modem will help resolve a stuck stale session.
Certainly on 20CN, turning off the Modem/Router for an hour always cleared stale sessions, and Plusnet gave similar advice for 21CN when they had quite a few stale session problems with those Network issues.

Unfortunately, in a lot of cases, it's still necessary to get Plusnet to kill the stale session.

If you can find the paperwork that says the DLM interprets an 30 minute or hour outage differently to a few seconds of no signal (not even the sync pre-amble) then happy to mode advice.

Have been doing the occasional full kit power cycle for a year now, and nothing untoward has resulted.

Also not I say 'I don't recall this happening' so now as you say it seems to be a PlusNet thing will add that to the memory core. Maybe other providers have it but just clear it and users are none the wiser.

I too have often done a few short (less than a minute) disconnections within quarter of an hour when swapping kit around and suffered no ill effects.

This 30 minute thing seems to be a recent "internet myth" to add to the many others . IIRC it first came along as an exaggerated way of waiting for a PPP session to drop normally at the ISP, for those with no (or no obvious) PPP session close facility in their router.

If I just want a re-sync until recently I just pulled the HG612 power cable out of the HG612 socket, not touching the router at all. Waited say 20 seconds and plugged it back in.

Edited by RobertoS (Wed 26-Aug-15 11:54:46)

In reply to a post by MrSaffron:

If you can find the paperwork that says the DLM interprets an 30 minute or hour outage differently to a few seconds of no signal (not even the sync pre-amble) then happy to mode advice.

Have been doing the occasional full kit power cycle for a year now, and nothing untoward has resulted.

Also not I say 'I don't recall this happening' so now as you say it seems to be a PlusNet thing will add that to the memory core. Maybe other providers have it but just clear it and users are none the wiser.

The details about some of the DLM counters are all over on kitz, especially the forum. Yes you can often get away with a quick resync now and again if you've had no other issues with your connection. DLM counts the disconnects in 15 minute intervals.

Plusnet forums were littered with threads last summer/autumn with the consequences of stale sessions as a result of some network outages (3 IIRC). I have no idea if the "problem" is just a Plusnet thing, I have not researched how other ISPs systems handle a stuck stale session should one arise, they may well clear it and users are none the wiser.

However, as I have already said rebooting/turning of the modem as opposed to clicking Disconnect and turning off the Router, will do nothing for a stale session. You must remember that if a users SNRM is below 6 at the time they will end up with a lower sync speed. Turning off/rebooting a modem should generally be an absolute last resort with connection problems.