Hello Colin,

Thanks for the extra information. Would the following text capture your
clarification?

Dan: I've also added some additional text to address your proposal.

"I.2.2.1 RFC 4566, "a=" attribute

The ABNF syntax of RFC2327 does not support the use of "-" in an attribute
name however despite stating that attributes names must be in the US-ASCII subset of ISO-10646/UTF-8. The ABNF syntax of RFC4566 was updated to support the
inclusion of "-" to address this inconsistency. Therefore the use of attribute names containing "-" is problematic for RFC2327 implementations as several examples of attribute names containing "-" were registered prior to the
definition of RFC4566. RFC2327 Implementors may consider exceptions when
parsing an "a=" where attribute names containing "-" are involved.

Beyond the addition of "-" in attribute names, the RFC4566 ABNF "token" syntax  defines additional characters (see item 22/I.2.4.2) that would also pose similar problems."

Regards, Christian

Colin Perkins wrote:
> On 5 Jun 2007, at 02:40, Christian Groves wrote:
>> The document Albrecht originally pointed to is now an Appendix to
>> ITU-T H.248.49. This was done to ensure that Albrecht's work was
>> captured. The latest draft can be found at:
>> http://ftp3.itu.int/av-arch/avc-site/2005-2008/0703_She/TD-62.zip
>>
>> I think Randell's point that the use of "-" in attribute names
>> between RFC2327 and RFC4566 should also be captured in the Appendix.
>> Better that these sorts of issues are documented. Something along the
>> lines of:
>>
>>
>>        "I.2.2.1 RFC 4566, “a=” attribute
>>
>> The syntax of RFC2327 does not support the use of “-“ in an attribute
>> name however the syntax of RFC4566 has been updated to support the
>> inclusion of “-“. Therefore the use of attribute names containing “-“
>> is problematic for RFC2327 implementations however several examples
>> of attribute names containing “-“ were registered prior to the
>> definition of RFC4566. RFC2327 Implementors may consider exceptions
>> when parsing an “a=” where these attribute names containing “-“ are
>> involved. "
>
> It's not that simple, since RFC 2327 is inconsistent. The ABNF allows
> only alphanumeric characters in attribute names, but the text only
> states that attribute names "must be in the US-ASCII subset of
> ISO-10646/UTF-8".
>
_______________________________________________
Sip-implementors mailing list
Sip-implementors@cs.c...
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors