[AVTCORE] draft-ietf-avtcore-rfc5285-bis-05 -- fun special case

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

Suppose that in the offer and the answer all of the identifiers are less
than 15.  And suppose that mixing one-byte and two-byte formats is *not*
negotiated.

RTP packets are sent containing one-byte extension headers, and
everything is going along well, and suddenly, the current data part for
an extension is over 16 bytes.  That data can't be encoded in the
one-byte format.

I think there needs to be a rule that a UA can't commit to the one-byte
format unless all of the extensions that might be sent are defined to
have data lengths between 1 and 16 bytes.  So instead of the current
rule

    A client MUST NOT send an extension header with the one-byte format
    if any negotiated valid identifier exceeds 14 and extmap-allow-mixed
    is not negotiated.

we need

    A client MUST NOT send an extension header with the one-byte format
    if:
        (1) extmap-allow-mixed is not negotiated, and
	(2) (a) some negotiated valid identifier is more than 14, or
	    (b)some negotiated extension may have a data length of 0
	    bytes or more than 16 bytes.

Dale