Assigning an auto-generated link-local IPv6 address for a VRRPv3 cluster

A virtual link-local IPv6 address can be auto-generated and assigned as the virtual IPv6 address of a VRRPv3 session.

The default VRRPv3 implementation allows only the link-local address that is configured on a physical interface to be used as the virtual IPv6 address of a VRRPv3 session. This limits configuring a link-local address for each VRRP instance on the same physical interface because there can be only one link-local address per physical interface. To auto-generate and assign a virtual link-local IPv6 address as the virtual IPv6 address of a VRRPv3 cluster, use the following steps on either an IPv6 VRRPv3 owner or backup device.

From privileged EXEC mode, enter global configuration mode.
```
device# configure terminal
```

Globally enable IPv6 VRRP.
```
device(config)# ipv6 router vrrp
```

Configure the Ethernet interface link for the owner device.
```
device(config)# interface ve 3
```

Configure the global IPv6 address of the interface.
```
device(config-vif-3)# ipv6 address fd3b::3/64
```

Assign the device to virtual router ID (VRID) 2.
```
device(config-vif-3)# ipv6 vrrp vrid 2
```
Note: You can assign a VRID number in the range of 1 through 255.

Designate this router as a VRRPv3 owner device.
```
device(config-vif-3-vrid-2)# owner
```

Automatically generate the IPv6 link-local address for the VRID for use in the local network.
```
device(config-vif-3-vrid-2)# ipv6-address auto-gen-link-local
```

Enable the VRRP session.
```
device(config-vif-3-vrid-2)# activate
```

The following example shows the auto-generation of a virtual link-local IPv6 address and its allocation as the virtual IPv6 address of a VRRPv3 session on an IPv6 VRRPv3 owner router.

device# configure terminal
device(config)# ipv6 router vrrp
device(config)# interface ve 3
device(config-vif-3)# ipv6 address fd3b::3/64
device(config-vif-3)# ipv6 vrrp vrid 2
device(config-vif-3-vrid-2)# owner
device(config-vif-3-vrid-2)# ipv6-address auto-gen-link-local
device(config-vif-3-vrid-2)# activate