What is Virtual Routing Redundancy Protocol? In short VRRP is a standards based protocol that provides redundant default gateways when multiple routers/switches are connected to the same Layer 2 network. A virtual IP address is shared between one or more routers/switches providing redundancy against a router/switch failure.

We’ve been using VRRP in conjunction with SMLT to make sure that either core ERS 8600 switch in a cluster could assume the default gateway for any specific VLAN should the other switch fail. While I’m not at liberty to get into specifics I can tell you that we recently ran straight into a wall with our VRRP configuration. We had about 60+ VLANs (port based) on an ERS 8600 switch cluster where the VRRP ID for each VLAN was set to “1”. While Nortel had previously said this configuration was supported, we ran into significant issues testing some new software code for the 8600.

In short Nortel is now advising that you MUST have unique VRRP IDs. Nortel recommends as best practice that you use the VLAN ID but that can be problematic since valid values for the VLAN ID are between 1..4096 and valid values for the VRRP ID are between 1..512. In my case the VLAN IDs were between 1 and 200 so I was able to match them up.

config vlan <VLAN ID> ip vrrp <VRRP ID> address <IP ADDRESS>
config vlan <VLAN ID> ip vrrp <VRRP ID> backup-master enable
config vlan <VLAN ID> ip vrrp <VRRP ID> enable

ERS8600:5# config vlan 1 ip vrrp 1 address 10.10.1.1
ERS8600:5# config vlan 1 ip vrrp 1 backup-master enable
ERS8600:5# config vlan 1 ip vrrp 1 enable
ERS8600:5# config vlan 2 ip vrrp 2 address 10.10.2.1
ERS8600:5# config vlan 2 ip vrrp 2 backup-master enable
ERS8600:5# config vlan 2 ip vrrp 2 enable
ERS8600:5# config vlan 9 ip vrrp 9 address 10.10.9.1
ERS8600:5# config vlan 9 ip vrrp 9 backup-master enable
ERS8600:5# config vlan 9 ip vrrp 9 enable

I believe Nortel is now recommending RSMLT in place of VRRP which we’ll be using going forward. If you’ve been using a VRRP ID of 1 in every VLAN you might want to consider changing your configuration. I hope to write a post about RSMLT in the near future detailing how to configure it and the advantages using RSMLT over VRRP.

A personal note of Thanks to Richard M. and Roger G. from Nortel for their help and assistance in troubleshooting this problem.

Cheers!