Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 589)

192.53.5.1. Hosts use the virtual router MAC address in routed traffic they send to their default IP
gateway (in this example, 192.53.5.1).
Virtual router IP address
VRRP does not use virtual IP addresses. Thus, there is no virtual IP address associated with a virtual
router. Instead, you associate the virtual router with one or more real interface IP addresses configured
on the router that owns the real IP addresses. In
VRRP overview on page 586, the virtual router with
VRID1 is associated with real IP address 192.53.5.1, which is configured on interface e1/6 on Switch 1.
VRIDs are interface-level parameters, not system-level parameters, so the IP address you associate
with the VRID must already be a real IP address configured on the Owner interface.
NOTE
You can associate a virtual router with a virtual interface. A virtual interface is a named set of physical
interfaces.
When you configure the Backup router for the VRID, specify the same IP address as the one you
specify on the Owner. This is the IP address used by the host as its default gateway. The IP address
cannot also exist on the Backup router. The interface on which you configure the VRID on the Backup
router must have an IP address in the same subnet.
NOTE
If you delete a real IP address used by a VRRP entry, the VRRP entry also is deleted automatically.
NOTE
When a Backup router takes over forwarding responsibilities from a failed Master router, the Backup
forwards traffic addressed to the VRID MAC address, which the host believes is the MAC address of the
router interface for its default gateway. However, the Backup router cannot reply to IP pings sent to the
IP addresses associated with the VRID. Because the IP addresses are owned by the Owner, if the
Owner is unavailable, the IP addresses are unavailable as packet destinations.
Master negotiation
The routers within a VRID use the VRRP priority values associated with each router to determine which
router becomes the Master. When you configure the VRID on a router interface, you specify whether
the router is the Owner of the IP addresses you plan to associate with the VRID or a Backup router. If
you indicate that the router is the Owner of the IP addresses, the software automatically sets the router
VRRP priority for the VRID to 255, the highest VRRP priority. The router with the highest priority
becomes the Master.
Backup routers can have a priority from 3 through 254, which you assign when you configure the VRID
on the Backup router interfaces. The default VRRP priority for Backup routers is 100.
Because the router that owns the IP addresses associated with the VRID always has the highest
priority, when all the routers in the virtual router are operating normally, the negotiation process results
in the Owner of the VRID IP addresses becoming the Master router. Thus, the VRRP negotiation results
in the normal case, in which the host’s path to the default route is to the router that owns the interface
for that route.
Virtual router IP address
FastIron Ethernet Switch Layer 3 Routing Configuration Guide 589
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