Mulipoint GRE Keep Alives

[joeharb]

From what I understand keepalives don't work on a multipoint GRE configuration.  Is there any method to bring down the hub tunnel interface if connectivity to the spokes is lost?  We currently utilized point to point GRE's and the keep alive works without issue. 

Thanks,

Joe

[Akash Agrawal]

Hi Joe,

Just want to clarify requirement of having keepalive for GRE tunnel. How are you pushing traffic over GRE tunnel. If you are running any IGP protocol, when spoke is lost, protocol will go down and no traffic will be forwarded over GRE tunnel.

Regards,

Akash

[joeharb]

We are migrating to an dynamic protocol but currently we are static and are using weights to influence the path we prefer, these are injected into our internal dynamic routing protocol.  So we are static to the sites that are connected to the GRE tunnels.

Thanks,

Joe

[Akash Agrawal]

As per below CCO document, keepalive not supported on multipoint GRE tunnel. This is very old document, not sure if any recent change is there.

But to solve purpose, you can track the static route using ip sla. or check if BFD is supported on multipoint GRE tunnel

Note: GRE tunnel keepalives are only supported on point-to-point GRE tunnels. Tunnel keepalives are configurable on multipoint GRE (mGRE) tunnels but have no effect.

http://www.cisco.com/c/en/us/support/docs/ip/generic-routing-encapsulation-gre/64565-gre-tunnel-keepalive.html