Hot Standby Router Protocol (HSRP) provides high-availability by providing first-hop routing redundancy for IP hosts on networks configured with a default gateway IP address. HSRP is used in a group of routers for selecting an active device and a standby device. Hosts send the packets to the default gateway to the active router and when the active router fails, the standby router takes over transparently.
Most IP hosts have a single IP address configured as the default gateway. This default gateway is a Virtual IP (VIP) address that is assumed by the active HSRP device on the network. To maintain transparency of the failover mechanism, the HSRP devices also use a virtual MAC address corresponding to this VIP so that the ARP entries on ...
