Vrrp Load Balancing Mode - HP MSR Series Configuration Manual

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.
Virtual MAC address assignment
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.
In an IPv4 network, a load-balanced VRRP group works as follows:
1. The master assigns virtual MAC addresses to all members, including itself. This example assumes
that the virtual IP address of the VRRP group is 10.1.1.1/24, Router A is the master, and Router B
is the backup. Router A assigns 000f-e2ff-0011 to itself and 000f-e2ff-0012 to Router B.
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