The VRRP Master router periodically sends advertisements to a reserved multicast group address. The VRRP Backup routers listen for advertisements and one of the backups will assume the Master role, if necessary. A VRRP router can support many virtual router instances, each with a unique VRID/IP address combination. The election process provides dynamic failover to one of the remaining VRRP Backups should the Master become unavailable.

The virtual IP address shared by a group of VRRP routers on a given network segment functions as the next-hop IP address used by neighboring hosts. The VRRP Master router simply forwards packets that have been received from hosts using the VRRP Master as the next-hop gateway. The existence of a VRRP Master and one or more VRRP Backups is transparent to the neighboring hosts.

The advantage gained from using VRRP is a default path with higher availability, but without requiring configuration of dynamic routing or router discovery protocols on every end host.

VRRP on HP ProCurve switches is interoperable with other routers that support RFC 3768.

VRRP operational aspects include:

Preempt delay timer to allow other protocols to complete their convergences

Preemptive mode can be disabled to prevent VRRP router flapping

Default Advertisement interval of 1 second

Default Detection time of 3.6 seconds

XRRP support on 5300xl switch

Similar in concept to VRRP, the HP ProCurve XL Router Redundancy Protocol (XRRP) provides the equivalent mechanism in the HP ProCurve Switch 5300xl series for backup functionality. Like VRRP, XRRP presents a virtual router to the end node connections whose IP and MAC address can transition from the master HP ProCurve Switch 5300xl to the backup HP ProCurve Switch 5300xl in the event the master HP ProCurve Switch 5300xl interface fails.

XRRP does not interoperate with VRRP, but can coexist in a VRRP environment without interference.

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HP 3500yl, 5200zl manual Xrrp support on 5300xl switch