EIGRP Holdtime value on GRE tunnels

merryllem · ‎08-19-2008

Greetings All,

What is the recommended EIGRP holdtime value on GRE tunnels. I have a backup link using ipsec/gre that goes thru the internet. Earlier today we had an outage that caused us to use our ipsec/gre internet backup link. Everything would have been great but for some reason EIGRP ajacency kept on flapping during that time so the back up link was almost useless. Im not sure if it was load that caused the peers not to respond to the hello's in a timely fashion or if was something else. (without load the adjacency is stable)

royalblues · ‎08-20-2008

Did you ever receive the following logs during the EIGRP flaps - The %TUN-5-RECURDOWN

This happens when the route to the tunnel destination address using the tunnel interface itself.

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094690.shtml

The neighbors can also flap if there is some instability in the network path but i think th default hold timer for EIGRP (i.e15 secs) should be fine even if you have a latency of around 300ms between the neighbors.

Narayan

Richard Burts · ‎08-20-2008

Merrylle

I have had somewhat similar experience with EIGRP running over IPSec GRE tunnels at a customer site. We changed the EIGRP timers to 15 and 45 and it seems to be more stable.

HTH

Rick

HTH

Rick