I believe Iñaki is only expressing a *desire* that the Contact be
mandatory in these case - not that there is currently such an explicit
requirement.
The tables in 3261 are notorious for not being sufficient to convey
nuances. They are often refined in the text.
There are some cases when a 1xx needs to have a Contact, and other times
when it is important that it not have a contact.
Paul
Valentin Nechayev wrote:
>>>>>> I??aki Baz Castillo <[EMAIL PROTECTED]> wrote:
>
>> Hi, as Bob Penfield pointed in a previous mail, RFC3261 doesn't
>> clarify if a 1XX response (that creates an early-dialog) MUST or not
>> contain a "Contact" header (that would be need, for example, to send a
>> BYE to terminate the early dialog instead of using a CANCEL).
>
> Why do you think so? See table in section 20:
>
> Header field where proxy ACK BYE CAN INV OPT REG
> ___________________________________________________________
> Contact R o - - m o o
> Contact 1xx - - - o - -
> Contact 2xx - - - m o o
> Contact 3xx d - o - o o o
>
> 'o' in crossing of "1xx" and "INV" means "optional" and this is explained
> in the section:
>
> ===
> "Optional" means that an element MAY include the header field in a
> request or response, and a UA MAY ignore the header field if present
> in the request or response (The exception to this rule is the Require
> header field discussed in 20.32).
> ===
>
> For finishing of early dialog, I suppose you should extract contact if it is
> sent in response, and avoid to change remote target otherwise.
>
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