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New Member

dead sessions with vpdn

Dead sessions with VPDN (l2tp)!!! In our LNS routers, we can see those sessions and they seem to be fine; but they are actually dead for some reasons. We are using 7200 with IOS 12.2(13)T5. Here is the partial configuration relating to the problems:

vpdn enable

vpdn source-ip


vpdn-group ISP-LNS


protocol l2tp

virtual-template 1

local name isp-lns

l2tp tunnel password xxxxxxxxxxxxxx

l2tp tunnel timeout no-session 10




interface Virtual-Template1

ip unnumbered Loopback1

ip tcp adjust-mss 1452

no logging event link-status

peer default ip address pool sun_au

no keepalive

ppp mtu adaptive

ppp lcp predictive

ppp authentication chap pap

ppp ipcp predictive

ppp timeout idle 600

A couple of observations here:

1) From the remote (customer) side, ADSL modems could not get IP addresses (showing up as as IP address)

2)From ISP side (on our LNS routers), we can see those customers’ ID “connected and alive” but they are actually dead. Since VPDN only allows one VPDN tunnel for one customer ID, the customers were rejected.

3)The command “l2tp tunnel timeout no-session 10” doesn’t seem to be working. What kind of correlations are between the command “l2tp tunnel timeout no-session 10” and command “ppp timeout idle 600”? My understanding is that after 600 idle time, ppp closes the particular virtual interface; then after 10 seconds, the virtual tunnel relating to that virtual interface should be brought down too.

Bottom line is that I would like to terminate those tunnels after customers being idle for a while (say 600 seconds). any hints, ideas will be greatly appreciated.


New Member

Re: dead sessions with vpdn

i duplicated the problem by shutting down the ADSL modem. LNS routers suppose to drop the tunnel; no, the LNS router still show the tunnel:

Vi290 PPPoVPDN 00:00:08

now i can't connect to internet after i turn the adsl modem back on.

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