Implementing and Explain High Availability with HSRP
The Cisco proprietary Hot Standby Router Protocol (HSRP) is a first-hop redundancy protocol (FHRP) intended to allow for transparent fail-over of the first-hop IP router, and is detailed in RFC 2281 . HSRP ensures high network availability by giving IP hosts on Ethernet, Fiber Distributed Data Interface (FDDI), Bridge-Group Virtual Interface (BVI), LAN Emulation (LANE), or Token Ring networks with a default gateway IP address with first-hop routing redundancy. In a group of routers, HSRP is used to pick an active router and a backup router. The active router is the router of choice for routing packets in a group of router interfaces; the standby router is the router that takes over when the current router fails or when predefined criteria are satisfied. HSRP active and standby routers use UDP port 1985 to transmit greeting messages to the multicast address 224.0.0.2. The virtual router is essentially an IP and MAC address combination set as the default gateway by end de...