NetComm NTC-990 - Manual (Page 53)

9.4 How to configure VRRP
Virtual Router Redundancy Protocol (VRRP) is a non-proprietary redundancy protocol described designed
to increase the availability of the default gateway servicing hosts on the same subnet. This increased
reliability is achieved by advertising a "virtual router" (an abstract representation of master and backup
routers acting as a group) as a default gateway to the host(s) instead of one physical router. Two or more
physical routers are then configured to stand for the virtual router, with only one doing the actual routing at
any given time. If the current physical router that is routing the data on behalf of the virtual router fails, an
arrangement is made for another physical router to automatically replace it. The physical router that is
currently forwarding data on behalf of the virtual router is called the master router.
Master routers have a priority of 255 and backup router(s) can have priority between 1-254.
A virtual router must use 00-00-5E-00-01-XX as its (MAC) address. The last byte of the address (XX) is the
Virtual Router Identifier (VRID), which is different for each virtual router in the network. This address is used
by only one physical router at a time, and is the only way that other physical routers can identify the master
router within a virtual router.
Revision 1.55 NetComm Limited
March 2009
52