Subject: Comment on rekeying in draft-ietf-ospf-ospfv3-auth-03

From: Paul Wells <[email-masked]>
Date: Tue, 11 Nov 2003 13:20:27 -0600

A concern I have with the current version of draft-ietf-ospf-ospfv3-auth is
that it does not specify a method for rekeying an authenticated OSPFv3 link
without breaking the adjacency.  In practice, I think such a mechanism will
be needed for the following reasons:

1. The security provided by a static key decreases with time.  The
experience of 802.11 static WEP keys is one example of this.

2. Our customers aren't going to like a solution that requires even brief
outages for periodic rekeying.

Non-disruptive re-keying of a link should be possible by establishing an
additional input SA with the new key.  Once all the routers on a link have
done this, the transmit SAs can be moved over.  Finally, once all the
routers have moved to the new key, the old input SAs can be removed.  The
trick will be in reliably controlling and synchronizing this sequence.

If this is a problem that we're going to solve, I'd suggest that putting it
into the draft, at least as a "SHOULD", will make it more likely that
implementations will interoperate.

Thanks.

- Paul Wells

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From: Acee Lindem <[email-masked]>
Date: Tue, 11 Nov 2003 23:07:24 -0500

Paul Wells wrote:

>routers have moved to the new key, the old input SAs can be removed.
>
This is a good point - I also think this should be included in the draft.

>The
Not sure that this should be specified - it has typically been
implementation specific.