Alcatel-Lucent 7750 SR-OS, Configuration Manual

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Page 302 7750 SR OS Router Configuration Guide
VRRP Overview
The Virtual Router Redundancy Protocol (VRRP) for IPv4 is defined in the IETF RFC 3768,
Virtual Router Redundancy Protocol . VRRP for IPv6 is specified in draft-ietf-vrrp-unified-spec-
02.txt . VRRP describes a method of implementing a redundant IP interface shared between two or
more routers on a common LAN segment, allowing a group of routers to function as one virtual
router. When this IP interface is specified as a default gateway on hosts directly attached to this
LAN, the routers sharing the IP interface prevent a single point of failure by limiting access to this
gateway address. VRRP can be implemented on IES service interfaces and on core network IP
interfaces.
If the master virtual router fails, the backup router configured with the highest acceptable priority
becomes the master virtual router. The new master router assumes the normal packet forwarding
for the local hosts.
Figure 12 displays an example of a VRRP configuration.
Figure 12: VRRP Configuration
OSRG006
Non-Owner
ALA-3
vrld 100
Priority 150
Owner
ALA-2
vrld 100
Non-Owner
ALA-1
vrld 100
Priority 200
Internet
Backup Master Backup
Virtual
Router ID
(VRID)