Re: [AVTCORE] Coments on draft-ietf-avtcore-rfc5285-bis-05

[[e-mail] (Dale R. Worley)]

Thanks for looking at my comments and doing what you can with them.  I
suppose overall, I wish that 5285 was a lot clearer, and in particular,
that it put in one place all the rules that relate offers and answers.
But that would require a complete editorial overhaul.

However, there is are a couple of point that could be addressed.  In
section 4.1.2 paragraph 2, it says

   Since it is expected that (a) the number of extensions in
   any given RTP session is small and (b) the extensions themselves are
   small, the one-byte header form is preferred and MUST be supported by
   all receivers.

This says that all receivers must support the one-byte format.  But I
can't find a similar statement that all receivers must support the
two-byte format, so it seems that support for that format is optional.
And if that's true, it means that a device that can receive only the
one-byte format needs a way to force the sender to only send the
one-byte format.

Another point is:

> > 4.2.  One-Byte Header
> > 
> > The ID value 15 is reserved.  But there is also the invalid case
> > where the ID field is 0 and the len field is non-zero.  That case
> > should probably be included in the same exception processing as for
> > ID value 15.
>
> > [Roni Even] It says that ID=0 MUST not be used value =0 is padding
> > (both ID and len field) so you are asking for text about what to do
> > if there is  header with 0 in the ID part but some value in the len
> > part. I assume that good policy will be the same as for ID 15 but
> > any error behavior can be expected (ignore all header extension
> > ,treat like padding ...) since this case is not discussed in
> > RFC5285.

My thinking is that if the draft is careful to specify the processing of
the invalid case of ID=15 in the one-byte format, then it would
similarly make sense for the draft to specify the processing of the
invalid case ID=0,len>0.

Dale