Avaya P332GT-ML, Installation And Configuration Manual

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Chapter 12 Avaya P330 Layer 3 Features
106 Avaya P332GT -ML User’s Guide
VRRP (Virtual Router Redundancy Protocol) Configuration
VRRP Overview
VRRP is an IETF protocol designed to support redundancy of routers on the LAN,
as well as load balancing of traffic. VRRP is transparent to host stations, making it
an ideal choice when redundancy, load balancing and ease of configuration are all
required.
The concept underlying VRRP is that a router can backup other routers, in addition
to performing its primary routing functions. This redundancy is achieved by
introducing a virtual router. A virtual router is a routing entity associated with
multiple physical routers. The routing functions of the virtual router are performed
by one of the physical routers with which it is associated. This router is known as
the master router. For each virtual router, VRRP selects a master router. If the
selected master router fails, another router is selected as master router.
In VRRP, two or more physical routers can be associated with a virtual router, thus
achieving extreme reliability. In a VRRP environment, host stations interact with the
virtual router. They are not aware that this router is a virtual router, and they are
not affected when a new router takes over the role of master router. This makes
VRRP fully interoperable with every host station.
VRRP can be activated on an interface using a single command while allowing for
the necessary fine-tuning of the many VRRP parameters. For a detailed description
of VRRP, refer to VRRP standards and published literature.