OPTIONS sip:user@example.org SIP/2.0
Via: SIP/2.0/UDP host4.example.com:5060;branch=z9hG4bKkdju43234
Max-Forwards: 70
From: "Bell, Alexander" <sip:a.g.bell@example.com>;tag=433423
To: "Watson, Thomas" < sip:t.watson@example.org >
Call-ID: badaspec.sdf0234n2nds0a099u23h3hnnw009cdkne3
Accept: application/sdp
CSeq: 3923239 OPTIONS
l: 0