SIP: Find-MeAliceProxyUser B1User B2User B3User B4AliceProxyUser B1User B2User B3User B4[01]INVITE[02]INVITE[03](100 Trying)[04]180 Ringing[05]180 RingingRequest Timeout[06]CANCEL[07]200 OK[08]487[09]ACK[10]INVITE[11]480 Not Logged In[12]ACK[13]INVITE[14]486 Busy Here[15]ACK[16]INVITE[17]180 Ringing[18]180 Ringing[19]200 OK[20]200 OK[21]ACK[22]ACKBoth Way RTP[23]BYE[24]BYE[25]200 OK[26]200 OKRFC5359: Find-Me