[asterisk-dev] Broken SIP dialog if INFO messages received beforefinal OK

[Karl H. Putz]

Section 12.1.1 of RFC 3261.  Check out the last portion of the copied  
text:
12.1.1 UAS behavior When a UAS responds to a request with a response  
that establishes a dialog (such as a 2xx to INVITE), the UAS MUST copy  
all Record-Route header field values from the request into the  
response (including the URIs, URI parameters, and any Record-Route  
header field parameters, whether they are known or unknown to the UAS)  
and MUST maintain the order of those values. The UAS MUST add a  
Contact header field to the response. The Contact header field  
contains an address where the UAS would like to be contacted for  
subsequent requests in the dialog (which includes the ACK for a 2xx  
response in the case of an INVITE).

The issue is that the header exists under most conditions except in  
the case where a SIP INFO digit is passed prior to Asterisk responding  
to the original Invite with the OK.


Karl H. Putz
(614)571-0899







On Apr 19, 2010, at 11:28 AM, Nick Lewis wrote:

>> Double checking the RFC confirms that the 2XX response to an INVITE
> requires the Contact Header.
>
> Where is this specified? I have looked at RFC2976 and it seems to
> prohibit a Contact Header in the 2XX response
>
>          Header                    Where    INFO
>          ------                    -----    ----
>          Contact                     R       o
>          Contact                    1xx      -
>          Contact                    2xx      -
>          Contact                    3xx      -
>          Contact                    485      -
>
>
> -- N_L
>
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