Incorrect layer 2 topology in networks with VRRP routers

[Morten Brekkevold]

VRRP, as defined by RFC5798 (http://tools.ietf.org/html/rfc5798) defines to reserved series of MAC addresses to identify virtual routers defined by VRRP setups.

These series are 00-00-5E-00-01-<XX> and 00-00-5E-00-02-<XX>, where XX is the virtual router id number.

The numbers may well be re-used across networks, resulting in non-unique MAC addresses being observed. NAV's cam logger has been observed to create adjacency candidates from switch ports based on re-used VRRP addresses. If no other candidates were discovered on the same port, the topology detector would select this candidate as the actual physical next-hop neighbor.

The cam logger should ignore these series of MAC addresses as real adjacency candidates. The same case may possibly apply for HSRP.