http://www.rfc-editor.org/rfc/rfc5723.txt
RFC 5723: Internet Key Exchange Protocol Version 2 (IKEv2) Session Resumption, Y. Sheffer, H. Tschofenig2010-01-01T23:00:00-00:00A client can reconnect to a gateway from which it was disconnected. The proposed approach encodes partial IKE state into an opaque ticket, which can be stored on the client or in a centralized store, and is later made available to the IKEv2 responder for re-authentication. We use the term ticket to refer to the opaque data that is created by the IKEv2 responder. This document does not specify the format of the ticket but examples are provided. [STANDARDS-TRACK]