Vrrp Group Overview - HP 4800G Series Configuration Manual

Configuring a default route for network hosts facilitates your configuration, but also requires high
performance stability of the device acting as the gateway. Using more egress gateways is a common
way to improve system reliability, introducing the problem of routing among the multiple egresses.
Virtual Router Redundancy Protocol (VRRP) is designed to address this problem. VRRP adds routers
that can act as network gateways to a VRRP group, which forms a virtual router. Routers in the VRRP
group elect a master through the VRRP election mechanism to take the responsibility of a gateway, and
hosts on a LAN only need to configure the virtual router as their default network gateway.
VRRP is an error-tolerant protocol, which improves the network reliability and simplifies configurations
on hosts. Deploying VRRP on multicast and broadcast LANs such as Ethernet, you can ensure that the
system can still provide highly reliable default links without changing configurations (such as dynamic
routing protocols, route discovery protocols) when a device fails, and prevent network interruption due
to failure of a single link.
VRRP has two versions: VRRPv2 and VRRPv3. VRRPv2 is based on IPv4, and VRRPv3 is based on
IPv6. The two versions implement the same functions but provide different commands.

VRRP Group Overview

VRRP combines a group of routers (including a master and multiple backups) on a LAN into a virtual
router called VRRP group.
A VRRP group has the following features:
A virtual router has a virtual IP address. A host on the LAN only needs to know the IP address of the
virtual router and uses the IP address as the next hop of the default route.
Every host on the LAN communicates with external networks through the virtual router.
Routers in the VRRP group elect the gateway according to their priorities. When the master acting
as the gateway fails, to ensure that the hosts in the network segment can communicate with the
external networks uninterruptedly, the other routers in the VRRP group elect a new gateway to
undertake the responsibility of the failed router.
Figure 1-2 Network diagram for VRRP
Host A
Host B
Host C
As shown in Figure
address. Hosts on the Ethernet use the virtual router as the default gateway.
The router with the highest priority of the three routers is elected as the master to act as the gateway,
and the other two are backups.
Virtual router
Router A
Router B
Network
Router C
1-2, Router A, Router B, and Router C form a virtual router, which has its own IP
1-2