The Virtual Router Redundancy Protocol (VRRP) was developed in 1998 as an open standard protocol. VRRP is the result of an Internet Engineering Task Force (IETF), and it’s described in RFC 5798 (VRRPv3). VRRP was designed as an open standard protocol, but it uses some patents from Cisco. Its function is comparable to Cisco Hot Standby Router Protocol (HSRP), or to the Common Address Redundancy Protocol (CARP). VRRP solves a very specific problem at the network edge: It offers highly available virtual router interfaces, or in simple words: A highly available default gateway.
Note This article is a bit Brocade-minded, especially with regard to the terminology. Redundant paths in a network are always a curse. Always? Not always. It depends on the protocol and the kind of network. In a Ethernet network you have Spanning Tree which eliminates redundant paths and builds a loop free network. What about redundant paths in a storage network? When iSCSI and NFS is used, then usually TCP/IP is used on top of Ethernet.