eap Mailing List: Re: Issues & Fixes: Ordered delivery of EAP messages

[Bernard Aboba (bernard_aboba]

> Ordered delivery & duplicate rejection aren't the same thing.

In general, that's true.  But if you have an ACK/NAK protocol that only 
allows a single packet in flight other than retransmissions, doesn't 
effective duplicate rejection imply ordered delivery?

> Suppose that the conditions you specify are met for the EAP peer and
> authenticator, as well.  Does that solve the problem?

If EAP were to implement duplicate rejection within a short time window, yes 
that would solve the problem.  We discussed this during the development of 
RFC 3748, partly out of the desire to reconcile EAP with IEEE 802.1X-2001 
which utilized a monotonically increasing Identifier field.  During that 
discussion we found that there were EAP implementations (such as the Solaris 
version, as I recall) that did not implement a duplicate rejection window.  
That is how the ordering guarantee found its way into RFC 3748, so as to 
guarantee that those implementations would work.