> > In our design, we chose to have a separate dedicated message per action,
> > rather than using fewer messages and decorating each with appropriate
> flags
> > and AVPs to mean different things.
> >
> > For example, we could say "if the session lifetime is set to 0 in PANA-
> Foo
> > message, it means the peer shall terminate the session". This could
> replace
> > the "PANA-Termination-Request". But it'd get us into trouble as we need
> to
> > define various permutations of AVPs, flags, and their values to define
> the
> > semantics of each message. With the separate message types, boundaries
> are
> > cleaner, IMHO. Comments?
> >
> It's not about the number of messages alone, number of AVPs alone, etc.
> It's how all the different permutations are combined. As you imply here,
> the message header, the message types, the AVPs, etc. are a hierarchy,
> and one can draw the lines in different places. IMHO, the message header
> should be best left to context lookup and transport (reliability and
> sequencing) and message verification (hashing and the like) functions,

Are you suggesting we do not include "Message Type" in the PANA header?

> the message types to major PANA state transitions or specific functions
> (like ping), and the AVPs as options within the state change or
> function. 


In order to better understand what you are suggesting, can you please tell
us what we need to change in our current design? Given that:

- We have phases (handshake, authentication and authorization, access,
re-authentication, termination).
- Each phase has a set of expected message types and specific flows (e.g.,
handshake: PCI, PSR, PSA; termination: PTR, PTA; etc.).
- Message type is carried in the PANA header
- Each message type is defined to include certain set of AVPs (e.g., PSR:
EAP, Algo).


> Finally, since PANA is effectively a transport protocol for
> EAP, EAP should be treated as a Payload which can be carried over the
> protocol's different modes of transport with as little linkage to the
> state of PANA beneath as possible. I don't see any of these lines
> clearly drawn, which may be the source of some of your headaches at this
> stage.



> >>>  Another optimization allows optionally carrying the first
> >>>    EAP Request/Response message in PANA-Start-Request/Answer message
> as
> >>>    described in Section 4.3.
> >>>
> >>>
> >> Another optimization. I'm feeling very sorry for the poor
implementor...
> >>
> >
> > We could remove that.
> >
> I'm not sure you want to, I would think that it would be the preferred
> method of operation in fact.
> 
> Now, if you completely decouple your PANA states from the type of EAP
> message being carried, and position the EAP message as something that
> can effectively show up as a Payload AVP at anytime, then perhaps you
> can have the best of both worlds here.

Alper






> 
> - Mark


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