Automatic generation of a virtual link-local address for VRRPv3

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.

When IPv6 link-local address auto-generation is configured for IPv6 VRRP, a virtual IPv6 link-local address is generated automatically using the EUI-64 result of the virtual MAC address. The virtual IPv6 link-local address is generated for a specific VRRP instance and the virtual link-local address is carried in VRRPv3 advertisements. The auto-generation process is defined in RFC 5798 allowing cross-vendor platform support. This ability to generate a link-local address automatically depends on the existence of a consistent virtual MAC address in the local network.

If the virtual link-local address is configured manually, the configured address takes precedence over the automatically generated address. The administrator should ensure that the configured virtual link-local address is consistent across all routers in the LAN. When the manually configured address is removed, the auto-generated address is used.

If there is a mismatch in the IPv6 addresses field, RUCKUS devices drop the advertisements that are sent by backup VRRP routers. The advertisements from the master VRRP router are not dropped regardless of the IPv6 address comparison. The virtual MAC must be consistent on the local network. When the virtual MAC is modified, the virtual link-local address is regenerated.

As a RUCKUS proprietary protocol, VRRP Extended version 3 (VRRP-Ev3) is not supported.