UCARP allows a couple of hosts to share common virtual IP addresses in order to
provide automatic failover. It is a portable userland implementation of the
secure and patent-free Common Address Redundancy Protocol (CARP, OpenBSD’s
alternative to the patents-bloated VRRP).

Strong points of the CARP protocol are: very low overhead, cryptographically
signed messages, interoperability between different operating systems and no
need for any dedicated extra network link between redundant hosts.

Authors:
---------
* Frank DENIS
* Eric Evans
* David H
* Richard Bellamy
* Russell Mosemann - neutral mode and bug fixes.