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Concentrator Not Reachable

theograham1612
Grafter
Posts: 215
Registered: 04-09-2013

Concentrator Not Reachable

Hey Guys and Gals,
So last night around 0035 my internet disconnected and the error I received was "Concentrator Not Reachable" after doing a quick Google search I then turned off my modem and router for 10 minutes and then turned them back on and my connection worked.
But my questions are will this happen often?
Will this affect DLM on my line i.e. slow my connection?
Has the time been reduced to say 5 minutes instead of 10?
Also can someone tell me if interleaving is on? As I want to get a lower ping.
Thanks
Theo
8 REPLIES
Community Veteran
Posts: 19,101
Thanks: 443
Fixes: 21
Registered: 31-08-2007

Re: Concentrator Not Reachable

It could have been BT maintenance, however I don't know what you found googling but it was not good advice. You should avoid rebooting the Modem if at all possible, especially after dark (yes it could affect DLM, but hopefully as a one off you may get away with it).. Logging into your Router and clicking Disconnect to drop the PPP session, wait a while and then click Connect should re-establish the connection. It's possible that you may have to wait for the previous stale session to time-out.
Depending on where such maintenance takes place you may not be able to re-connect until it's complete.
Community Veteran
Posts: 19,101
Thanks: 443
Fixes: 21
Registered: 31-08-2007

Re: Concentrator Not Reachable

See http://usertools.plus.net/status/archive/1407760912.htm for maintenance upto Sunday night and http://usertools.plus.net/status/archive/1408373449.htm for this week.
Bear in mind that sometimes the maintenance may not complete until 0600.
If your googling found you this, Chris normally gives excellent advice but as previously stated I would advise logging into the Router and click Disconnect, wait half a minute, you can then turn the Router off. Leave it off for the advised 10-15 minutes, but leave the Modem alone. After powering up the Router, login and click Connect.
If this fails and you are desperate to reconnect, then follow the same procedure but after the Router has been off for about a minute, turn off the Modem. After 15 minutes turn the Modem on and wait for all the lights to settle and it's finished booting, before turning on the Router, logging in and clicking Connect. I that also fails I'd log into the Router, click Disconnect  and turn the Router of after about a minute and leave things until after 0600.
theograham1612
Grafter
Posts: 215
Registered: 04-09-2013

Re: Concentrator Not Reachable

The DSL light on the modem was off.
Also the thread I found was -
http://community.plus.net/forum/index.php/topic,114808.msg989806.html#msg989806
Community Veteran
Posts: 19,101
Thanks: 443
Fixes: 21
Registered: 31-08-2007

Re: Concentrator Not Reachable

That timeout was reduced to 2 minutes and hasn't changed AFAIK (see towards the end iof the thread), but the issue only seemed to arise where people switched off the Router without Disconnecting the PPP Internet session first. I suspect that it is also an issue when the PPP session is interrupted by network maintenance. Unfortunately you don't have the option to Disconnect the PPP session on some Routers, so only have the power off option.
If the Modem DSL light was off, in that case it would be OK to turn off the Modem but only in those circumstances would there be no issues at all. I would not recommend unnecessary turning off of the Modem otherwise. But that suggests your interruption was more localised. Normal Network maintenance would not interrupt sync between you and the Cab. I would still recommend using the procedure above wherever possible.
Also note http://community.plus.net/forum/index.php/topic,114808.msg989761.html#msg989761
Community Veteran
Posts: 19,101
Thanks: 443
Fixes: 21
Registered: 31-08-2007

Re: Concentrator Not Reachable

Sorry, forgot to mention about the ping times. It's not possible to change it, the depth of interleaving is determined by the DLM and isn't configurable as it is on ADSL.
theograham1612
Grafter
Posts: 215
Registered: 04-09-2013

Re: Concentrator Not Reachable

Thanks Anotherone
Is it ok to restart the router, I feel that after a while my connection in games become a bit..stale to be nice and when I was on ADSL I would restart it and it would be fine, but since I have fibre I don't want to lose any connection I'm wondering if there's anywhere to restart the router without DLM stepping in.
Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: 26-11-2011

Re: Concentrator Not Reachable

Restarting your router is absolutely fine. DLM acts when it registers a loss of sync which is controlled by your Modem.
Chris Pettitt
Cloud Environments Engineer
Community Veteran
Posts: 19,101
Thanks: 443
Fixes: 21
Registered: 31-08-2007

Re: Concentrator Not Reachable

Whilst that is of course perfectly correct Chris, it's still better to log in to the Router and click Disconnect to drop the PPP Internet session before and waiting about 30 seconds before powering off or Restarting.  After you power  back up, then Log in and click Connect to re-establish an Internet PPP session. This should avoid any issues with stale sessions stopping you reconnect quickly. If you just want to Gateway hop, then instead of powering off or Restarting, after the 30 seconds.just click Connect.
IIRC doing it this way, also means that the Radius log of the PPP session shows this as User Initiated rather than a random session drop.
As a further aside, if you ever "Reset" the Router, you may have to wait about 15 minutes before you can reconnect whilst TR-069 loads your broadband login credentials unless you do it manually (and preferably having disabled TR-069 but that's all getting more technical). HTH.