The Common Address Redundancy Protocol or CARP is a computer networking protocol which allows multiple hosts on the same local area network to share a set of IP addresses
Its primary purpose is to provide failover redundancy, especially when used with firewalls and routers. In some configurations, CARP can also provide load balancing functionality
CARP provides functionality similar to VRRP and to Cisco Systems' HSRP
It is implemented in several BSD-based operating systems and has been ported to Linux (ucarp)