[c-nsp] Cisco 7206 - L2TP Tunnel Problem after tunnel clear / lotsof wt-con

[Mike]

We tested the same vpdn-config on the IOS Version 12.3(15a) but the problem 
remains, wich IOS Version would you recommend ?
We are talking to a Redback SE400 Smartedge OS Version seos-2.6.5.3
Wich settings would you recommend to fix this problems ?

greets
mike

----- Original Message ----- 
From: "Oliver Boehmer (oboehmer)" <oboehmer at cisco.com>
To: "Mike" <mike at ostw.de>; <cisco-nsp at puck.nether.net>
Sent: Tuesday, April 11, 2006 11:19 AM
Subject: RE: [c-nsp] Cisco 7206 - L2TP Tunnel Problem after tunnel clear / 
lotsof wt-con


Mike <> wrote on Tuesday, April 11, 2006 10:50 AM:

> Hi,
>
> we have about  500 vpdn-sessions (dsl-user) terminated on a 7206
> Cisco-Router running  IOS Version 12.2(16)B2. Everything works fine,
> until the l2tp tunnel will be resettet (got some problems with our
> carrier in the past).
> If the tunnel gets resettet, the sessions come in again very quick,
> gets authenticated by radius but a lot of the sessions have the state
> "wt-con" when i take a look at "show vpdn"
> These sessions just "hang" , they dont drop and come in again.
> We found one setting, but this is only a simple workaround:
> if our carrier splits the tunnel into seperate smaller tunnels (each
> tunnel has 100 vpdn-sessions) the sessions will be terminated
> correctly and there are no more sessions with the "wt-con" state.
> What can be the reason for this lots of "wt-con" vpdn-sessions? Any
> ideas ? How can i avoid this ?

Wt-con is the state we are in when we got ICRQ, we sent ICRP but have
not received ICCN from the LAC yet, so you might be seeing some control
msgs getting dropped somewhere and you're retransmitting (show vpdn
tunnel all [ id <id>] should show this). Which LAC (vendor) are you
talking to? You might also want to upgrade to a recent IOS as I recall
some fixes in this area (especially in interop with other vendors)..

oli