H3C Technologies H3C S10500 Series Switches - Manual (Page 134)

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VRRP works in standard protocol mode, and includes two versions: VRRPv2 and VRRPv3. The two
versions implement the same functions but apply to different networks: VRRPv2 is for IPv4 networks, and
VRRPv3 is for IPv6 networks. For more information, see “ VRRP standard protocol mode .”
VRRP standard protocol mode
Introduction to VRRP group
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 a master that acts as the gateway according to their priorities. The
other routers function as the backups. When the master fails, to ensure that the hosts in the network
segment can uninterruptedly communicate with the external networks, the backups in the VRRP
group elect a new gateway to undertake the responsibility of the failed master.
Figure 32 Network diagram for VRRP
Host A
Host B
Host C
Router A
Router B
Router C
Virtual router
Network
As shown in Figure 32 , Router A, Router B, and Router C form a virtual router, which has its own IP
address. Hosts on the Ethernet use the virtual router as the default gateway.
The router with the highest priority among the three routers is elected as the master to act as the gateway,
and the other two are backups.
NOTE:
•
The IP address of the virtual router can be either an unused IP address on the segment where the VRRP
group resides or the IP address of an interface on a router in the VRRP group. In the latter case, the router
is called the IP address owner.
• Only one IP address owner can be configured for a VRRP group.
• Status of a router in a VRRP group includes master, backup, and initialize.