Acronym for
Common Address Redundancy Protocol.
CARP is a free alternative to the Virtual Router Redundancy Protocol (
VRRP)
and the Hot Standby Router Protocol (
HSRP). Its primary
purpose is to allow multiple
hosts on the same
network segment to share an IP address. CARP works by
allowing a group of hosts on the same network segment to share an
IP address. This group of hosts is referred to as
a redundancy group. The redundancy group is assigned an IP address that is
shared among the group members. Within the group, one host is designated the
master and the rest as back-ups. The master host is the one that currently holds
the shared IP. It responds to any traffic or
ARP requests
directed towards it. Each host may belong to more than one redundancy group at a
time.
[Adapted from OpenBSD.org]