IETF RFC 4555 PDF

This document describes the MOBIKE protocol, a mobility and multihoming extension to Internet Key Exchange (IKEv2). MOBIKE allows the IP addresses associated with IKEv2 and tunnel mode IPsec Security Associations to change. A mobile Virtual Private Network (VPN) client could use MOBIKE to keep the connection with the VPN gateway active while moving from one address to another. Similarly, a multihomed host could use MOBIKE to move the traffic to a different interface if, for instance, the one currently being used stops working.