;tag=[call_number] To: Bob Call-ID: [call_id] CSeq: 1 REGISTER Contact: "Bob" Content-Length: 0 Expires: 300 ]]> ;tag=[call_number] To: Bob Call-ID: [call_id] CSeq: 1 REGISTER [field0] Contact:"Bob" Content-Length: 0 Expires: 300 ]]>