> H.323 standard has already defined how the lower network
> layer QOS (e.g.,
> RSVP [guaranteed, controlled, best effort], ATM QOS [CBR,
> rt-VBR, nrt-VBR,
> ABR, UBR]).
>
> Now, if we define H.323 application layer QOS only without
> defining the
> mapping, this will not provide backward compatibility to the
> existing H.323
> standard.
>
> This is the concern.
>
> So, the "scope" should include the "mapping" of the H.323 QOS
> to the lower
> network layer QOS.

I don't think we can define such a mapping. There are many ways to use
ATM. The one we used in Annex C is based on CBR AAL5. AAL1 or AAL2 could
be candidates. VBR is also something to consider. We alse did single
channel adaptation. We could multiplex. There is no reason why we need to
specify the ATM transport and associated QoS mechanism.

On the diffserv side, I am also not convinced that there is much to say
since network operators are free to use diffserv in any way they see fit.