How H.323 to SIP Calls Work

For H.323 to SIP IWF calls, if 2833-related information is to be sent in the INVITE, the SIP interface of the SIP session agent has to be configured with the rfc2833-mode parameter set to preferred.

The following example shows an INVITE without 2833 in the SDP:

Apr  5 04:28:50.073 On 127.0.0.1:5070 sent to 127.0.0.1:5060
INVITE sip:780@192.168.200.6:5060 SIP/2.0
Via: SIP/2.0/UDP 127.0.0.1:5070;branch=z9hG4bKIWF0000gl2018604agg71c0;acme_irealm=external;acme_sa=192.168.1.6
Contact: "jdoe"<sip:127.0.0.1:5070>
GenericID: 114421133000000@000825010100
Supported: 100rel^M
From: "msmith"<sip:192.168.200.68:5060>;tag=000000ab00011940
To: <sip:780@192.168.200.6:5060>
Call-ID: 7f00000113ce000000ab000101d0@127.0.0.1
CSeq: 2 INVITE
Content-Length: 225
Content-Type: application/sdp
v=0
o=IWF 3 3 IN IP4 192.168.1.6
s=H323 Call
c=IN IP4 192.168.1.6
t=0 0
m=audio 5214 RTP/AVP 0  18
a=rtpmap:0 PCMU/8000/1
a=rtpmap:18 G729/8000/1
a=fmtp:18 annexb=no
m=video 5216 RTP/AVP 31
a=rtpmap:31 H261/9000/1