Configuring Layer 3 Redundancy with Hot Standby Routing Protocol – HSRP
What is HSRP?

HSRP defines a standby group of routers, with one router as the active router. HSRP provides gateway redundancy by sharing IP and MAC addresses between redundant gateways. The protocol consists of a virtual MAC address and IP address that are shared between two routers that belong to the same HSRP standby group. HSRP can optionally monitor both LAN and serial interfaces via a multicast protocol.

An HSRP standby group comprises these entities:

  • One active router
  • One standby router
  • One virtual router
  • Other routers