H3C Technologies H3C SecBlade LB Cards - Manual (Page 18)

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Figure 6 VRRP in load sharing mode
A router can be in multiple VRRP groups and hold a different priority in a different group.
As shown in
Figure 6 , the following VRRP groups are present:
{
VRRP group 1—Router A is the master. Router B and Router C are the backups.
{
VRRP group 2—Router B is the master. Router A and Router C are the backups.
{
VRRP group 3—Router C is the master. Router A and Router B are the backups.
For load sharing among Router A, Router B, and Router C, hosts on the LAN need to be configured
to use VRRP group 1, 2, and 3 as the default gateways, respectively. When configuring VRRP
priorities, make sure that each router holds such a priority in each VRRP group so that it will take
the expected role in the group.
VRRP load balancing mode
In a standard-mode VRRP group, only the master can forward packets. The backups are in listening state.
You can create multiple VRRP groups to share load, but you must assign different gateways to the hosts
on the LAN.
Load balancing mode simplifies configuration and improves forwarding efficiency. In load balancing
mode, a VRRP group maps its virtual IP address to multiple virtual MAC addresses: one virtual MAC
address for each group member. The master uses these virtual MAC addresses of the member routers to
respond to IPv4 ARP requests or IPv6 ND requests from hosts. Therefore, every router in this VRRP group
can forward traffic and traffic from hosts is distributed across the VRRP group members.
VRRP load balancing mode uses the same master election, preemption, and tracking mechanisms as the
standard mode, and adds new mechanisms as described in the following sections.
Assigning virtual MAC addresses
In a load balanced VRRP group, the master assigns virtual MAC addresses to the member routers and
answers the ARP requests or ND requests from different hosts. The backup routers do not answer the ARP
requests or ND requests from the hosts.