REGISTER sip:bell-tel.com SIP/2.0
Via: SIP/2.0/UDP pluto.bell-tel.com
From: <sip:jon.diligent@bell-tel.com>;tag=7
To: sip:watson@bell-tel.com
Call-ID: 17320@pluto.bell-tel.com
CSeq: 1 REGISTER
Contact: sip:tawatson@example.com