This document describes an extension to the Internet Key Exchange
Protocol version 2 (IKEv2) that allows for faster detection of
Security Association (SA) desynchronization using a saved token.
When an IPsec tunnel between two IKEv2 peers is disconnected due to a
restart of one peer, it can take as much as several minutes for the
other peer to discover that the reboot has occurred, thus delaying
recovery. In this text, we propose an extension to the protocol that
allows for recovery immediately following the restart. [STANDARDS-TRACK]