CANOGA PERKINS CanogaOS Configuration Guide - Manual (Page 153)

CanogaOS Configuration Guide
Proprietary & Confidential Canoga Perkins Metro Ethernet Switches Page 153 of 350
20 Configuring VRRP
This chapter provides an overview of Virtual Router Redundancy Protocol (VRRP) and its
implementation.
VRRP eliminates the risk of a single point of failure inherent in a static default routing
environment. It specifies an election protocol that dynamically assigns responsibility for a virtual
router to one of the VRRP routers on a LAN. One of the major advantages of VRRP is that it
makes default path available without requiring configuration of dynamic routing on every
end-host.
20.1.1 References
The VRRP module is based on :
RFC 3768 (VRRP) Knight, S., et.al "Virtual Router Redundancy Protocol (VRRP)".
20.1.2 Terminology
Backup Router The VRRP router that is backing up an IP address. It
assumes forwarding responsibility for the virtual IP address
if the Master fails.
Critical IP The IP address that a VRRP router sends/receives messages on for
a particular session.
IP Address Owner The VRRP Router that has the virtual router's IP address(es) as
real interface address(es). This is the router that, when up,
will respond to packets addressed to one of these IP addresses
for ICMP pings, TCP connections, etc.
Master Router The VRRP router that owns the IP address (i.e., is being backed
up), and which is the default router for forwarding for that
IP address.
Virtual IP The IP address that is being backed up by a VRRP session.
Virtual Router A router managed by VRRP that acts as a default router for hosts
on a shared LAN. It consists of a Virtual Router Identifier and
a set of associated IP addresses across a common LAN. A VRRP
Router might backup one or more virtual routers.
VRRP Router A router running the Virtual Router Redundancy Protocol. It might
participate in one or more virtual routers.
20.1.3 VRRP Process
Typically, end hosts are connected to the enterprise network through a single router (first hop
router) that is in the same Local Area Network (LAN) segment. The most popular method of
configuration is for the end hosts to statically configure this router as their default gateway. This
minimizes configuration and processing overhead. The main problem with this configuration