I have an ASA5520 that has 70 LAN-to-LAN tunnels currently attached to it. Frequently something out on Internet causes some of the tunnels to drop (Today it happened to be several of my Comcast cable sites). I have (2) Cisco 3005 Concentrators that I previously used for VPN tunnels that are currently just handling client access. I can enable any of the suspect tunnels from the ASA onto the 3005 and the tunnel immediately goes active.
Has anyone else experienced this issue? Is there some type of setting (MTU?) that allows the 3005 to connect even when the ASA5520 will not? I have tried contacting the provider in the past with no success.