I have a lan to lan tunnel setup between an 1811 vpn router and a 3030 concentrator. The tunnel works fine until the traffic hits a certain threshhold, then the users start to see delays and timeouts. I have tried adjusting mtu settings on both ends of the tunnel and it helped to a certain point, but as traffic increased they still experience timeouts. I have verified that there is ample bandwidth on both ends of the vpn. Has anyone seen this before?
I have this problem too.