Problem with GRE TUNNELS and using IPSEC encryptor

[Harjit_Singh@notes.tcs.treas.gov]

Hello,
                      I will appreciate any help on this case.  I have a
scenario where I have setup VPN connection between two sites using GRE tunnels
running over Cylink IPSEC encryptors.  I have EIGRP routing protocol running
over the GRE tunnels for routing information.  It so happens that after the
connection has been up for few hours, GRE tunnels seem to get hung up.  This
problem gets resolved if the tunnel is restarted or some times by power cycling
the encryptors.

                  What could be possibly causing the encryptors to hang up GRE
tunnels?  Does any one have any feed back on this.

Sunny
(Tel# 703-747-9677)