INVITE sip:bob@biloxi.com SIP/2.0
Via: SIP/2.0/UDP 20.22.24.26:5060;
Via: SIP/2.0/UDP 192.168.1.10:5060;
   received=18.17.16.15:25588;branch=z9hG4bKnashds8
Record-Route: <sip:20.22.24.26;lr>
Max-Forwards: 70
To: Bob <sip:bob@biloxi.com>
From: Alice <sip:alice@atlanta.com>;tag=1928301774
Call-ID: a84b4c76e66710
CSeq: 314159 INVITE
Contact: <sip:alice@18.17.16.15:25588>
Content-Type: application/sdp
Content-Length: 142

  v=0
  o=alice 53655765 2353687637 IN IP4 20.22.24.27
  s=-
  t=0 0
  c=IN IP4 20.22.24.27
  m=audio 20333 RTP/AVP 0 1 3 99
  a=rtpmap:0 PCMU/8000