[SIPForum-discussion] Allow Header usage

HM Kias hmkias at gmail.com
Tue Aug 23 17:18:44 UTC 2011


The mandatory fields in the invite request of  most UA are








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. ***
> **
> 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
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sipforum.org/pipermail/discussion/attachments/20110823/23607a84/attachment-0002.html>

More information about the discussion mailing list