VRRP

Virtual Router Redundancy Protocol (VRRP) protection can be provided for the primary as well as for the secondary IP addresses of a VLAN. For multinetting, the IP address assigned to an VRRP virtual router identifier (VRID) can be either the primary or the secondary IP addresses of the corresponding VLAN.

For example, assume a VLAN v1 with two IP addresses: a primary IP address of 10.0.0.1/24, and a secondary IP address of 20.0.0.1/24.

To provide VRRP protection to such a VLAN, you must configure one of the following:

Configure VRRP in VLAN v1 with two VRRP VRIDs. One VRID should have the virtual IP address 10.0.0.1/24, and the other VRID should have the virtual IP address 20.0.0.1/24. The other VRRP router, the one configured to act as backup, should be configured similarly.

—OR—

Configure VRRP in VLAN v1 with two VRRP VRIDs. One VRID should have the virtual IP address as 10.0.0.1/24, and the other VRID should have the virtual IP address as 20.0.0.1/24.

It is possible for a VRRP VR to have additional virtual IP addresses assigned to it.

In this case, the following conditions must be met:

Multiple virtual IP addresses for the same VRID must be on the same subnet.
Multiple virtual IP addresses must all not be owned by the switch.

Assuming a VLAN v1 that has IP addresses 1.1.1.1/24 and 2.2.2.2/24, here are some more examples of valid configurations:

VRRP VR on v1 with VRID of 99 with virtual IP addresses of 1.1.1.2 and 1.1.1.3
VRRP VR on v1 with VRID of 100 with virtual IP addresses of 2.2.2.3 and 2.2.2.4
VRRP VR on v1 with VRID of 99 with virtual IP addresses of 1.1.1.98 and 1.1.1.99
VRRP VR on v1 with VRID of 100 with virtual IP addresses of 2.2.2.98 and 2.2.2.99

Given the same VLAN v1 as above, here are some invalid configurations:

VRRP VR on v1 with VRID of 99 with virtual IP addresses of 1.1.1.1 and 2.2.2.2 (the virtual IP addresses are not on the same subnet)
VRRP VR on v1 with VRID of 100 with virtual IP addresses of 2.2.2.2 and 1.1.1.1 (the virtual IP addresses are not on the same subnet)
VRRP VR on v1 with VRID of 99 with virtual IP addresses of 1.1.1.1 and 1.1.1.99 (one virtual IP address is owned by the switch and one is not)
VRRP VR on v1 with VRID of 100 with virtual IP addresses of 2.2.2.2 and 2.2.2.99 (one virtual IP address is owned by the switch and one is not).