Has anybody ever build a IPSec-VPN with a Cisco Router (for example 26xx) and a vigor -Router ? We have do that, and maybe anyone has try it before ?

We have sometimes the problem that a good working connection after a periode of time (for example 2 houres) freeze. The connection was not terminated but you are no more able to work on this connection.(No or only some data pass the Tunnel) Not even ...