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Concentrator not reachable

Flands
Newbie
Posts: 6
Registered: 18-08-2010

Concentrator not reachable

Hello,
I had the FTTC all set up last wednesday (11th) and it went down on friday and stayed down since. I keep getting the error message "Concentrator not reachable" I've tried a different thomson router off a family member who is also on the trial and this gives the same error. I have already raised this with plus.net support with ticket number 34730186  but was wondering if anybody else has been getting these problems ?
Any thoughts or suggestions would be great
Cheers
Flands
22 REPLIES
Plusnet Staff
Plusnet Staff
Posts: 12,169
Thanks: 18
Fixes: 1
Registered: 04-04-2007

Re: Concentrator not reachable

Hi,
Not seen that before, I'll have a look at the ticket in the morning when I'm back in the office. I presume you've rebooted the BT modem, what are the status lights on it showing?
Flands
Newbie
Posts: 6
Registered: 18-08-2010

Re: Concentrator not reachable

all the norm lights are showing on the bt modem, power, dsl and lan1. I had problems with my first Thomson router so had hoped it was just that one messing me about but as that one didn't respond to known ip address's using another Thomson router now all correctly configed. it's giving the same error.
Plusnet Staff
Plusnet Staff
Posts: 12,169
Thanks: 18
Fixes: 1
Registered: 04-04-2007

Re: Concentrator not reachable

Looks like one of my colleague's has already raised it as a fault and the testing shows there is a fault on the line. You could try and connect a PC direct to the BT modem and bypass the Thomson but I suspect this will give a similar error. Connect the ethernet cable from the BT modem to PC then on the PC do the following:
Go to Control Panel -> Network Connections
Create a new connection
Connect to the Internet
Set up my Connection Manually
Connect using a broadband connection that requires a username and password (PPPoE)
ISP Name - Plusnet
Enter the broadband username and password
Finish and click Connect
Make sure you have a firewall on the PC before connecting.
Flands
Newbie
Posts: 6
Registered: 18-08-2010

Re: Concentrator not reachable

Ok im glad its been looked into, tried connecting directly and "connection failed with error 651" So still no joy  Huh
Thanks for suggestion though
Flands
Plusnet Staff
Plusnet Staff
Posts: 12,169
Thanks: 18
Fixes: 1
Registered: 04-04-2007

Re: Concentrator not reachable

Looks like the same problem as reported in this thread:
http://community.plus.net/forum/index.php/topic,88204.0.html
I'm talking to BT now as there are 4 of you affected.
Wai
Newbie
Posts: 1
Registered: 18-09-2010

Re: Concentrator not reachable

Has anybody resolved this issue yet? As I've had it since the 07/09/10 and still no joy. I've tried connecting straight into the BT modem but still no luck. I've not had much feedback from Plusnet about what they are doing or much contact at all to be honest. The only time they have called me is when I called them and asked for a update!
Hugo
Dabbler
Posts: 19
Registered: 04-08-2010

Re: Concentrator not reachable

I've got the same issue, almost a week now. The fault has been passed to BT but no update as of yet.
Flands
Newbie
Posts: 6
Registered: 18-08-2010

Re: Concentrator not reachable

Hey
Its got to be at least 50+ days now and its still screwed, Can someone give me a call back please Ben/Dave to let me know what the next steps are going to be? as BT have come out and basically just said yeah its broken and needs to be configured/setup all over again, I called on Friday to be told id get a call back in a few mins up to an hour dunno if the guy i spoke to was about to finish his shift or go on lunch? but i got no call back regardless and have been left in the dark since friday when the bt engineer left.
Many Thanks
Flands
Plusnet Staff
Plusnet Staff
Posts: 12,169
Thanks: 18
Fixes: 1
Registered: 04-04-2007

Re: Concentrator not reachable

Flands, I'm waiting for an update from BT this afternoon, I'll be in touch later today.
Superuser
Superuser
Posts: 9,728
Thanks: 1,312
Fixes: 19
Registered: 22-08-2007

Re: Concentrator not reachable

I know this is a really old thread, but was an answer ever forth coming from BT?
Just what does this error message signify?  It has been reported by numerous people after the recent gateway MSO.  I cannot find a clear explanation of the error code anywhere on the internet.  Where it is referenced the suggested fix is to factory reset TG routers - seems somewhat drastic and rather points to an interface issue between the router and the BT modem which is not "resolved" by a power down.  All a bit strange!
Plusnet Staff
Plusnet Staff
Posts: 12,169
Thanks: 18
Fixes: 1
Registered: 04-04-2007

Re: Concentrator not reachable

Sort of, the error indicates that the router can't communicate with something further up the chain, in FTTP that usually means the OLT at the exchange. The physical link is up but the communication is failing after that point. I've seen it on FTTC too where again the physical connection is up (it's in sync) but there's a communication failure somewhere between the DSLAM and BRAS (again usually at the exchange).
We've seen various reasons and fixes, one of the easiest way to replicate it is to unplug the router from the BT modem without clicking disconnect and then plug a different router in. The BT modem will see the PPPoE connection as being up still while the router won't and then give that error because it can't communicate with the BRAS as that too still sees the PPPoE up. If you wait for the PPPoE timeout to kick in then it'll reconnect.
Of course that's not the most common time you see it but if you think about what happens in an MSO situation or the times that you see it, in a lot of them the PPP has dropped but some part of the chain between router and ISP hasn't seen it drop yet and still thinks it's up. Factory reset might fix it but it's probably more likely that the time it takes to factory reset, reboot the BT modem etc. is pretty similar to how long it takes for the PPP to timeout so waiting will probably fix it too. And in those cases that waiting doesn't fix (and neither does a factory reset) there's probably a fault with some of the kit between exchange and ISP.
mattturner
Grafter
Posts: 246
Thanks: 1
Registered: 25-06-2009

Re: Concentrator not reachable

Wow this is an old thread!
I've seen this before, but on FTTC. I've seen it happen when the PPP client is looking for a remote server to connect to but isn't getting a response.
In the past I've seen this happen when a PPP session is still up but the local end needs to send a termination packet.
The Technicolor router have a feature to do this and it can be enabled by configuring the PPP interface using these commands. Waiting 30 seconds for a LCP keepalive packet, the router will then identify that a session is still open and shut it down.
Quote
:ppp iflist
:ppp ifdetach intf=Internet
:ppp ifconfig intf Internet gracefulrestart enabled
:ppp ifattach intf=Internet
:saveall

You must run all of these commands, the ifconfig command won't run without the Internet interface first being detached.
Superuser
Superuser
Posts: 9,728
Thanks: 1,312
Fixes: 19
Registered: 22-08-2007

Re: Concentrator not reachable

Matt,
Thanks for this.  I resurrected this whilst researching the means and remedy for this condition following the numerous difficulties post the MSO.
Is this worth putting this in front of those who need to know (CRT + Others) as a test remedy for those who experience extended difficulties when trying to reconnect after events such as the recent MSO?  Some people were still struggling a week afterwards with no apparent means of fixing things other than getting BTOR out to "kick" something.
Is there merit in having the default setting in these routers changed to be this?
Would this "fix" apply to ADSL use as well?

Cheers,
Kevin
Community Veteran
Posts: 4,898
Thanks: 327
Fixes: 16
Registered: 10-06-2010

Re: Concentrator not reachable

I think gracefulrestart=enabled is supposed to be the default in the 10.2.5.2 FO firmware, although that setting appears to have been lost when re-configuring the router for ADSL use via its web interface.