Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 599)

FIGURE 67 Two routers configured for dual redundant network access for the host
In this example, Router 1 and Router 2 use VRRP-E to load share as well as provide redundancy to the
hosts. The load sharing is accomplished by creating two VRRP-E groups, each with its own virtual IP
addresses. Half of the clients point to Group 1's virtual IP address as their default gateway, and the
other half point to Group 2's virtual IP address as their default gateway. This enables some of the
outbound Internet traffic to go through Router 1 and the rest to go through Router 2.
Router 1 is the master for Group 1 (master priority = 110) and Router 2 is the backup for Group 1
(backup priority = 100). Router 1 and Router 2 both track the uplinks to the Internet. If an uplink failure
occurs on Router 1, its backup priority is decremented by 20 (track-port priority = 20) to 90, so that all
traffic destined to the Internet is sent through Router 2 instead.
Similarly, Router 2 is the master for Group 2 (master priority = 110) and Router 1 is the backup for
Group 2 (backup priority = 100). Router 1 and Router 2 are both tracking the uplinks to the Internet. If
an uplink failure occurs on Router 2, its backup priority is decremented by 20 (track-port priority = 20) to
90, so that all traffic destined to the Internet is sent through Router 1 instead.
VRRP/VRRP-E packet behavior
There are some differences in how VRRP and VRRP-E handle ARP and VRRP control packets, as
summarized below.
Gratuitous ARP
VRRP: Sent only once when the VRRP router becomes the master.
VRRP-E: Sent every two seconds by the virtual router master because VRRP-E control packets do not
use the virtual MAC address.
The source MAC address of the gratuitous ARP sent by the master is the virtual MAC address.
When a router (either master or backup) sends an ARP request or a reply packet, the MAC address of
the sender is the MAC address of the router interface. One exception is if the owner sends an ARP
request or a reply packet, in which case the MAC address of the sender is the virtual MAC address.
VRRP/VRRP-E packet behavior
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