From: Paul Kyzivat <[EMAIL PROTECTED]>

   I'd still like to know if email clients need to do this two pass 
   approach - first searching for all the references to determine if all 
   the handling requirements can be met, and then actually doing the 
   processing of the referenced parts?

Well, if you want to be able to process all valid MIME multipart
bodies, it seems to be unavoidable.  As far as I can tell, almost all
of the algorithm is prescribed by the RFCs.  The only specification
I've added is the subtle question of what strategy will be used to
choose from multipart/alternatives.  My first discussion some months
ago, I used the strategy "Can you choose so that the constraints are
satisfied?", which led to NP-completeness.  This version, which is
probably closer to what is intended by the RFCs, is "Make the choice
for each multipart/alternative without regard to whether it is adverse
to multiparts that contain you."

   Also, it *is* legal for proxies to process bodies. But its obviously not 
   required (by the protocol) for them to do so. Do we have a clue how the 
   handling parameter applies to proxies? I assume in effect they can just 
   ignore it and consider handling to be optional for all parts. Also, I 
   presume a proxy that cares about body parts might want to investigate 
   all the alternatives of a multipart/alternative, since it can't know 
   which one the recipient will choose.

As far as I can tell, proxies aren't allowed to reject messages
because they don't like their bodies, although I'm sure that in
specialized applications, they will.  But the interpretation of
handling parameters by such proxies will be determined by what the
"specialized application" is attempting to do; it's not in the scope
of RFCs.

Dale
_______________________________________________
Sip mailing list  https://www.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use [EMAIL PROTECTED] for questions on current sip
Use [EMAIL PROTECTED] for new developments on the application of sip

Reply via email to