This increases the availability and reliability of routing paths via automatic default gateway selections on an IP subnetwork.
VRRP can be used in Ethernet, MPLS and Token Ring networks with Internet Protocol Version 4 (IPv4), as well as IPv6.
One exception to this rule is when a physical router is configured with a higher priority than the current primary/active, which means that on connection to the network it will pre-empt the primary/active status.
Security is achieved by responding only to first hop packets, though other mechanisms are provided to reinforce this, particularly against local attacks.
[1]: §4.2 Work on VRRP started in 1997 with a first draft published by the Internet Engineering Task Force (IETF).
[4] IBM also claims covering patents and their statement is readable on the IETF webpage.
[1] Mellanox offers MAGP, a proprietary protocol based on VRRP that allows active-active operation.
[9] Foundry Networks developed VRRP-E(Extended), a proprietary version of VRRP that avoids a few limitations of RFC 3768[10][1]