bridge domain / transport-mode vlan passthrough

[mac87]

Hi all,

we have the following problem, our two ASRs are with bridge domain and routed BVI interface configured so that there is additionally hsrp communiaction. The interconnect links are with rewrite ingress tag pop 1 symetric configured, so that HSRP communication is established.

Links to customer do also have a rewrite ingress tag pop 1 symetric so that from customer site our hsrp vip is reachable. 

Problem here is our customer wants to transport its vrrp control packets through our Circuit but having the rewrite ingress tag pop 1 symetric on interfaces it looks like packets cannot be transitted. We have configured under bridge domain the transport-mode vlan passthrough but it doesn't look helpful. Any idea how we can get this problem solved?

Thanks!

[Aleksandar Vidakovic]

If HSRP works in this topology, VRRP should work as well. Do you see the VRRP packets getting punted to the RP CPU? Try with "debug punt-inject l3-packets vrrp interface BVI <n> detail". 

[mac87]

We run HSRP on routed BVI interface in bridge domain. But to make this work rewrite ingress pop 1 symmetric is necessary, as our bundle-ether interfaces are encapsulated with dot1q. 

Southbound our customer runs VRRP and wants his control packets transmitted over our network, but they get dropped because of the pop function.

[Aleksandar Vidakovic]

I'm still not sure it's the rewrite that plays a role here. Are you sure it's not the split horizon that prevents packets from being send back where they were received from?

[mac87]

Deleting the "transport-mode vlan passthrough", I got this problem fixed. Probably ASR was expecting for a vlan id, but we were popping it on access interface.