U 192.168.0.102:5060 -> 192.168.0.145:5060
  REGISTER sip:server.itginc.jp SIP/2.0..Content-Length: 0..Contact: <si
  p:192.168.0.102>..Call-ID: 1D829350-79CC-42FD-93B7-0FBC361C65E2@192.16
  8.0.102..From: <sip:vivian@server.itginc.jp>;tag=19895398..CSeq: 7 REG
  ISTER..To: <sip:vivian@server.itginc.jp>..Via: SIP/2.0/UDP 192.168.0.1
  02:5060....                                                          
#
U 192.168.0.145:5060 -> 192.168.0.102:5060
  SIP/2.0 200 OK..Via: SIP/2.0/UDP 192.168.0.102:5060..From: <sip:vivian
  @server.itginc.jp>;tag=19895398..To: <sip:vivian@server.itginc.jp>..Ca
  ll-ID: 1D829350-79CC-42FD-93B7-0FBC361C65E2@192.168.0.102..CSeq: 7 REG
  ISTER..Expires: 600..Content-Length: 0....