Vrrp Load Balancing Mode; Virtual Mac Address Assignment - HP MSR Series Configuration Manual

VRRP group 1—Router A is the master. Router B and Router C are the backups.
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• 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.
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To implement load sharing among Router A, Router B, and Router C, perform the following tasks:
Configure the virtual IP addresses of VRRP group 1, 2, and 3 as default gateway IP addresses for
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hosts on the subnet.
Assign the highest priority to Router A, B, and C in VRRP group 1, 2, and 3, respectively.
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VRRP load balancing mode

In a standard-mode VRRP group, only the master can forward packets and backups are in listening state.
You can create multiple VRRP groups to share traffic, but you must configure different gateways for hosts
on the subnet.
In load balancing mode, a VRRP group maps its virtual IP address to multiple virtual MAC addresses,
assigning one virtual MAC address to each member router. Every router in this VRRP group can forward
traffic and respond to IPv4 ARP requests or IPv6 ND requests from hosts. Because their virtual MAC
addresses are different, traffic from hosts is distributed across the VRRP group members. Load balancing
mode simplifies configuration and improves forwarding efficiency.
VRRP load balancing mode uses the same master election, preemption, and tracking mechanisms as the
standard mode. New mechanisms have been introduced to VRRP load balancing mode, as described in
the following sections.

Virtual MAC address assignment

In load balancing mode, the master assigns virtual MAC addresses to routers in the VRRP group. The
master uses different MAC addresses to respond to ARP requests or ND requests from different hosts. The
backup routers, however, do not answer ARP requests or ND requests from hosts.
In an IPv4 network, a load balanced VRRP group works as follows:
1. The master assigns virtual MAC addresses to all member routers, 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 for itself and 000f-e2ff-0012 for Router
B. See Figure 10.
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