Virtual Router Redundancy Protocol

A default gateway is a critical resource for connectivity. However, it's prone to a single point of failure. Thus, redundancy for the default gateway is required by the access point. If WAN backhaul is available, and a router failure occurs, then an access point should act as a router and forward traffic on to its WAN link.

Define an external VRRP (Virtual Router Redundancy Protocol) configuration when router redundancy is required in a wireless network requiring high availability.

The election of a VRRP master is central to the configuration of VRRP. A VRRP master (once elected) performs the following functions:

  • Responds to ARP requests
  • Forwards packets with a destination link layer MAC address equal to the virtual router MAC address
  • Rejects packets addressed to the IP address associated with the virtual router, if it is not the IP address owner
  • Accepts packets addressed to the IP address associated with the virtual router, if it is the IP address owner or accept mode is true

Nodes that lose the election process enter a backup state where they monitor the master for any failures. In case of a failure, one of the backups becomes the master and assumes the management of the designated virtual IPs. A backup does not respond to an ARP request, and discards packets destined for a virtual IP resource.

To define the configuration of a VRRP group:

  1. Select the Configuration → Devices → System Profile → VRRP tab from the web UI.
    Click to expand in new window
    Profiles - VRRP screen - VRRP tab
  2. Review the following VRRP configuration data to assess whether a new VRRP configuration is required or whether an existing VRRP configuration can be modified or removed:
    Virtual Router ID A numerical index (from 1 - 255) used to differentiate VRRP configurations. The index is assigned when a VRRP configuration is initially defined. This ID identifies the virtual router for which a packet is reporting status.
    Description A description assigned to the VRRP configuration when it was either created or modified. The description is implemented to provide additional differentiation beyond the numerical virtual router ID.
    Virtual IP Addresses The virtual interface IP address used as the redundant gateway address for the virtual route.
    Interface The interfaces selected on the access point to supply VRRP redundancy failover support.
    Priority A numerical value (from 1 - 254) used for the virtual router master election process. The higher the numerical value, the higher the priority in the election process.