;tag=[call_number]
To:
Call-ID: [call_id]
CSeq: [cseq] INVITE
Contact: sip:[local_ip]:[local_port]
Max-Forwards: 10
Content-Type: application/sdp
Content-Length: [len]
v=0
o=user1 53655765 2353687637 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 0 8
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
]]>