Subject: [IPsec] #22: Add section on simultaneous IKE SA rekey

From: Yaron Sheffer <[email-masked]>
Date: Wed, 26 Aug 2009 00:22:56 +0300

Tero:

2.8.1. Simultaneous CHILD_SA rekeying
Instead of simultaneous CHILD_SA rekeying, there should be section of
simultaneous IKE SA rekeying. Simultaneous CHILD_SA rekeying just results
few extra SAs that will disappear after next rekeys (at worst there will be
2 SA pairs, but all others will be deleted instead of being rekeyed as they
are not used. The simultaneous IKE SA rekeying is much more important case
to get correct, as both ends MUST agree on which IKE SA survive, as
otherwise they will move the CHILD SA to wrong IKE SA and their state is
completely messed up after that. This section should also explain that even
if the simultaneous rekeying of IKE SA is noticed only AFTER the whole
rekeying is already finished, both ends MUST still correctly detect it and
act based on the fact which IKE SA will survive. This means that the old IKE
SA should not be deleted too quickly after the IKE SA rekey finished, just
in case there happened to be simultaneous rekey in progress. The one doing
the delete should wait at least few minutes before deleting the old IKE SA,
so it can be sure that other end does not have simultaneous rekey going on
the IKE SA.
Paul: Not done. More specific text is needed. This is interesting, but
should be discussed on the list.
There was a long discussion of this issue in the past, see some pointers
here: http://www.ietf.org/mail-archive/web/ipsec/current/msg03516.html. We
would appreciate proposed text for such a new section.

Thanks,
	Yaron