ing V : SIP/2.0/UDP 176.5.8.2:5060;branch=z9hG4bK942834822.1 V : SIP/2.0/UDP 65.3.4.1:5060;branch=z9hG4bK343 f: sip:+45.67890@incoming.com;user=phone>;tag=6a589b1 t : ksip:+65.12345@incoming.com;user=phone>;tag=8657 i: a3-65-99-1d@65.3.4.1 m: sip:user@client.home.com CSeq: 1 INVITE SIP: Understanding the Session Initiation Protocol SIP/2.0 180 Ringing V : SIP/2.0/UDP 65.3.4.1:5060;branch=z9hG4bK343 f: sip:+45.67890@incoming.com;user=phone>;tag=6a589b1 t : sip:+65.12345@incoming.com;user=phone>;tag=8657 i: a3-65-99-1d@65.3.4.1 CSeq: 1 INVITE Alerting M10 SIP/2.0 200 OK V : SIP/2.0/UDP 176.5.8.2:5060;branch=z9hG4bK942834822.1 V : SIP/2.0/UDP 65.3.4.1:5060;branch=z9hG4bK343 f: ksip:+45.67890@incoming.com;user=phone>;tag=6a589b1 t : <sip:+65.12345@incoming.com;user=phone>;tag=8657 i: a3-65-99-1d@65.3.4.1 CSeq: 1 INVITE m: sip:user@client.home.com C : application/sdp l: 125 O=- 2890844565 2890844565 IN IP4 7.8.9.10 t=0 0 C=IN IP4 7.8.9.10 m=audio 5004 RTP/AVP 0 a=rtpmap:0 PCMU/8000 M11 SIP/2.0 200 OK V : SIP/2.0/UDP 65. 3.4.1:5060;branch=z9hG4bk341 f: <sip:+45.67890@incoming.com;user=phone>;tag=6a589b1 t : ip:+65.12345@incoming.com;user=phone>;tag=8657 i: a3-65-99-1d@65.3.4.1 CSeq: 1 INVITE M : sip:user@home.com C : application/sdp l: 125 O=- 2890844565 2890844565 IN IP4 7.8.9.10 t=0 0 C=IN IP4 7.8.9.10 m=audio 5004 RTP/AVP 0 a=rtpmap:0 PCMU/8000 M12 Connect ACK sip:user@home.com SIP/2.0 Call Flow Examples V: SIP/2.0/UDP 65.3.4.1:5060;branch=z9hG4bK453 Max-Forwards: 70 f: ssip+45.67890@incoming.com;user=phone>;tag=6a589b1 t:<sip+65.12345@incoming.com;user=phone>;tag=8657 i: a3-65-99-1d@65.3.4.1 CSeq: 1 ACK 10.5 Parallel Search In this example the caller receives multiple possible locations for the called party from a redirect server. Instead of trying the locations one at a time, the user agent implements a parallel search for the called party by simultaneously send- ing the INVITE to three different locations, as shown in Figure 10.5. The SIP specification gives an example of this behavior in a proxy server, which is