;tag=[call_number] To: [service] Call-ID: [call_id] CSeq: 1 INVITE Contact: sip:sipp@[local_ip]:[local_port] Max-Forwards: 70 Content-Type: application/sdp Content-Length: [len] v=0 o=- 42 42 IN IP[local_ip_type] [local_ip] s=- c=IN IP[media_ip_type] [media_ip] t=0 0 m=audio [media_port] RTP/AVP [pt] a=rtpmap:[pt] [codec] a=recvonly ]]> ;tag=[call_number] To: [service] [peer_tag_param] Call-ID: [call_id] CSeq: 1 ACK Contact: sip:sipp@[local_ip]:[local_port] Max-Forwards: 70 Content-Length: 0 ]]> Content-Length: 0 ]]>