INVITE sip:John_Smith@tct.hut.fi SIP/2.0
To: John Smith <sip:John_Smith@tct.hut.fi:5066;user=ip;maddr=131.228.16.2>
  ; tag = deadbeef
From: http://www.cs.columbia.edu
Call-ID: 0ha0isndaksdj@10.1.2.3
CSeq : 8 INVITE
Via: SIP/2.0/UDP 135.180.130.133
Content-Type: application/sdp
Contact: Joe Bob Briggs <urn:ipaddr:122.1.2.3> ; bar="foo baa", sip:kuik@foo.invalid
Via: SIP/2.0/UDP [aa:bb::1]:5061
l: 138

v=0
o=mhandley 29739 7272939 IN IP4 126.5.4.3
c=IN IP4 135.180.130.88
m=audio 492170 RTP/AVP 0 12
m=video 3227 RTP/AVP 31
a=rtpmap:31 LPC