Overview

This section describes how to configure and verify VRRP configuration and operational states.

  • All VRRP configurations work in VRRP context.

  • VRRP can be configured on physical ports, VLAN interfaces, and LAG interfaces.

  • VRRP mandates the associated interface to be routing interface.

In many networks, edge devices are configured to send packets to a statically configured default router. If this router becomes unavailable, devices that use it as a first-hop router become isolated from the network.

VRRP uses dynamic failover to ensure the availability of an end node default router. The IP address used as the default route is assigned to a virtual router (VR). The VR includes:

  • A Master router assigned to forward traffic designated for the virtual route

  • One or more prioritized Backup routers (If a Backup is forwarding traffic for the VR, it has replaced the Owner as the Master router.)

This redundancy provides a backup for gateway IP addresses (first-hop routers). If a VR Master router becomes unavailable, the traffic it supports will be transferred to a Backup router without major delays or operator intervention. This operation can eliminate single-point-of-failure problems and provide dynamic failover (and failback) support. As long as one physical router in a VR configuration is available, IP addresses assigned to the VR are always available. Edge devices can send packets to these IP addresses without interruption.

Advantages to using VRRP include:

  • Minimizing failover time and bandwidth overhead if a primary router becomes unavailable

  • Minimizing service disruptions during a failover

  • Providing backup for a load-balanced routing solution

  • Avoiding the need to make configuration changes in the end nodes if a gateway router fails

  • Eliminating the need for router discovery protocols to support failover operation