OPTIONS sip:user;par=u%40example.net@example.com SIP/2.0
To: sip:j_user@example.com
From: sip:caller@example.org;tag=33242
Max-Forwards: 3
Call-ID: semiuri.0ha0isndaksdj
CSeq: 8 OPTIONS
Accept: application/sdp, application/pkcs7-mime,
        multipart/mixed, multipart/signed,
        message/sip, message/sipfrag
Via: SIP/2.0/UDP 192.0.2.1;branch=z9hG4bKkdjuw
l: 0
