I would do some logging on both ends of the VPN to see which device is dropping the tunnel.
Do both ends of the tunnel have static IP addresses? If an IP changed at one end the tunnel would drop for a lot longer than a few seconds.
I found an existing problem on Cisco. CheckPoint and Cisco don't coexist properly. We're looking into the suggested solution. We ran DHCP then tried static, but the problem remained
Let me know about the IP's you are using for VPNs, Loopback or real IPs?
Use dynamic protocol for ip addressing, do not know use static IPs.
Are the ipsec lifetimes are set the same on both ends? The Cisco default ipsec lifetime is 3600 seconds which is one hour, once the lifetime expires the tunnel will be disconnected and reinitiate it again. You can change the ipsec lifetime by using the command "crypto ipsec security-association lifetime seconds ...".
Regards | Aref.