DMVPN spoke-to-spoke timeout?

hurricane1091

Hello all. I have a question in regards to DMVPN timeouts. I have the NHRP holdtime set to 900 seconds (15 minutes). When a dynamic tunnel forms, it is set for 15 minutes. However, it will never renew this timer even if traffic is flowing across the link. It will eventually expire, and then re-establish. Is there any way around this? A consecutive ping test shows the dropped pings during the time period that it times out before it re-establishes. This would drop a phone call. Is there any way around this?

networker050184

Well look at it this way, what needs to happen for it not to time out? Why is that not happening?

hurricane1091

I am not sure. The hub is set to use 900 second hold down timers as well. That will renew 1/2 way through it. However, the flags used there are "unique registered used" ( Type: dynamic, Flags: unique registered used)

From a spoke perspective, a tunnel to another spoke will have the flag "router" ( Type: dynamic, Flags: router). The hub will renew with the spokes, but spokes will not renew the tunnel with other spokes. Now, this makes sense because you wouldn't want a tunnel between spokes to form dynamically and then stay up forever. However, I was hoping there would be a way for the tunnel to stay up as long as traffic was going over it.

Everything works well. I have basically documented this in my CCNP thread but brought it here because it is really beyond the scope of the CCNP. Perhaps this is just the nature of NHRP & DMVPNs. Maybe it just knows not to try to renew the tunnel with the flags set on it are "router" since that is a dynamic spoke to spoke connection.