[SIPForum-discussion] Allow Header usage

[vijay baskar]

Hi

So in this case, how to make a decision if a remote side support certain
method.
We need to know that INFO is supported or not during the call setup phase,
are there any way to know that if remote side support INFO or not during the
INVITE->200Ok.

Thanks in advance

BRs
Vijay

2011/8/24 ZHANG Joey <Joey.Zhang at alcatel-lucent.com>

>  As in 13.2.1, it just says “should be”  not “must be” , and also in the
> chart list in 20.1, we can find out that Allow header is optional in invite.
> ****
>
> ** **
>
> ** **
>
> Section 20.1 ****
>
> Example:****
>
> Header field where proxy ACK BYE CAN INV OPT REG****
>
> ___________________________________________________________****
>
> Accept R - o - o m* o****
>
> Accept 2xx - - - o m* o****
>
> Accept 415 - c - c c c****
>
> Accept-Encoding R - o - o o o****
>
> Accept-Encoding 2xx - - - o m* o****
>
> Accept-Encoding 415 - c - c c c****
>
> Accept-Language R - o - o o o****
>
> Accept-Language 2xx - - - o m* o****
>
> Accept-Language 415 - c - c c c****
>
> Alert-Info R ar - - - o - -****
>
> Alert-Info 180 ar - - - o - -****
>
> Allow R - o - o o o****
>
> Allow 2xx - o - m* m* o****
>
> Allow r - o - o o o****
>
> Allow 405 - m - m m m****
>
> ** **
>  ------------------------------
>
> *From:* discussion-bounces at sipforum.org [mailto:
> discussion-bounces at sipforum.org] *On Behalf Of *HM Kias
> *Sent:* 2011年8月24日 1:19
>
> *To:* vijay baskar
> *Cc:* discussion at sipforum.org
> *Subject:* Re: [SIPForum-discussion] Allow Header usage
> ****
>
> ** **
>
> Hi, ****
>
>  ****
>
> The mandatory fields in the invite request of  most UA are ****
>
> Via****
>
> To****
>
> From****
>
> Call-ID****
>
> CSeq****
>
> Contact****
>
> Max-Forwards****
>
>  ****
>
> The allow header is an optional one. The header field must be present in a
> 405 Method Not Allowed response and should be included in a positive
> response to an OPTIONS request.****
>
> ** **
>
> On Mon, Aug 22, 2011 at 8:32 AM, vijay baskar <vijaybaskar.sm at gmail.com>
> wrote:****
>
> Hi,
>
> Is the Allow header is mandatory in INVITE and 200 OK, after reading the
> RFC it looks like it is mandatory.
> But there are some UA still accepting the INVITE/200 OK without Allow
> header.
>
> Please clarify.
>
>
>
> From RFC 3261:****
>
> 13.2.1 Creating the Initial INVITE ****
>
> *Since the initial INVITE represents a request outside of a dialog, its
> construction follows the procedures of Section 8.1.1. Additional processing
> is required for the specific case of INVITE. An Allow header field
> (Section 20.5) SHOULD be present in the INVITE. It indicates what methods
> can be invoked within a dialog, on the UA sending the INVITE, for the
> duration of the dialog. For example, a UA capable of receiving INFO requests
> within a dialog [34] SHOULD include an Allow header field listing the INFO
> method. *****
>
> 13.3.1.4 The INVITE is Accepted ****
>
> *The UAS core generates a 2xx response. This response establishes a
> dialog, and therefore follows the procedures of Section 12.1.1 in addition
> to those of Section 8.2.6. A 2xx response to an INVITE SHOULD contain the
> Allow header field and the Supported header field, and MAY contain the
> Accept header field. *****
>
>
>
> Thanks in advance.
>
> BRs
> Vijay
>
> _______________________________________________
> This is the SIP Forum discussion mailing list
> TO UNSUBSCRIBE, or edit your delivery options, please visit
> http://sipforum.org/mailman/listinfo/discussion
> Post to the list at discussion at sipforum.org****
>
>
>
>
> --
> HM Kias
> 91-9443467600****
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sipforum.org/pipermail/discussion/attachments/20110824/ec6315ab/attachment-0002.html>