[asterisk-users] OPTIONS to query endpoint capability

Tue Oct 25 13:13:16 CDT 2011

I have been sending OPTIONS requests both programatically (my own code),
manually via SIP VERIFY PEER x and automatcially by setting verify=yes in
sip.conf. The trouble is I do not see anything except an ACK 200 come back
from endpoints and it does not contain any SDP/codec info. . My goal is to
determine audio and video codec capability in advance of a call INVITE. I
notice the Asterisk generated OPTIONS does not specify any Accept header (ie
Accept=application/sdp). I was thinking maybe that is why I don't get any
SDP coming back. My own code generated OPTIONS includes the Accept header
and still I see no SDP.

Is Anyone able to query codec capability for any endpoints? I would like to
know how you do so.

Below is excerpt from the automatic OPTIONS query I see in the sip logs from
setting verify=true. No Accept header. Does anyone believe that to be the
problem? Notice the response has content length=0 and no SDP. Any ideas
appreciated

OPTIONS sip:991 at 192.168.1.4:5060 SIP/2.0

Via: SIP/2.0/UDP 192.168.1.2:5060;branch=z9hG4bK7f05f169

Max-Forwards: 70

From: "asterisk" <sip:asterisk at 192.168.1.2>;tag=as1fd2a50c

To: <sip:991 at 192.168.1.4:5060>

Contact: <sip:asterisk at 192.168.1.2:5060>

Call-ID: 010fdb653903a2022b99ed1d40c0b8db at 192.168.1.2:5060

CSeq: 102 OPTIONS

User-Agent: Asterisk PBX 1.8.6.0

Date: Mon, 24 Oct 2011 19:14:47 GMT

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO,
PUBLISH

Supported: replaces, timer

Content-Length: 0

<--- SIP read from UDP:192.168.1.4:5060 --->

SIP/2.0 200 OK

Via: SIP/2.0/UDP 192.168.1.2:5060;branch=z9hG4bK7f05f169

From: "asterisk" <sip:asterisk at 192.168.1.2>;tag=as1fd2a50c

To: <sip:991 at 192.168.1.4:5060>;tag=003d3418e2fce011b081701a0413e3f3

Call-ID: 010fdb653903a2022b99ed1d40c0b8db at 192.168.1.2:5060

CSeq: 102 OPTIONS

Contact: <sip:991 at 192.168.1.4:5060>

Allow: INVITE, OPTIONS, ACK, BYE, CANCEL, INFO, NOTIFY, MESSAGE, UPDATE

Server: SIPPER for PhonerLite

Content-Length: 0
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