I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. This ID is intended for the Standards Track. It defines an efficient way to resume an IKE/IPsec session using a previous established IKE SA without the need to re-run the key exchange protocol from the beginning. The approach is similar to that used by TLS session resumption, but modified for IKEv2. Summary: This draft is basically ready for publication, but has nits that should be fixed before publication. Technical comments: 4.3.1 does not require gateways to reject reused tickets (it's a SHOULD). Shouldn't there be some text in the security considerations about gateways accepting reused tickets or text to say it's not a security consideration because of x, y, and z? It's different than the considerations put forth in 9.8 because it addresses why the client must not present reused tickets. 4.3.2 states: "The client SHOULD NOT use this exchange type unless it knows that the gateway supports it." What is the mechanism to determine whether the gateways support these new exchanges? What happens when the client sends a request and the gateway doesn't support the response? What error message is returned from the gateway? This might all be defined elsewhere in the IKE suite of specs, but this ID should probably point to that text wherever it is. Editorial comments: 4.3.2: Should the may be MAY in the following: The first message may be rejected in? 4.3.2: r/value ./value. 5: Note 6 is missing a ")" 6.1: r/MUST be protected so that only unauthorized access is not allowed/MUST be protected so that only authorized access is allowed 9.3: r/as possible. and/as possible, and Cheers, spt