nalyticalsoc.org CSeq: 1000 BYE M23 SIP/2.0 200 OK Via: SIP/2.0/UDP 10.14.92.1:5060;branch= z9hG4bK24105.1 Via: SIP/2.0/UDP 1.2.3.4:5060;branch=z9hG4bK543 From: Ada Lovelace <sip:ada@language.org>;tag=65a3547e3 To: Charles Babbage <sip:babbage@analyticalsoc.org>;tag=9382 Call-ID: f6-32-9a-34-91-e7@analyticalsoc.org CSeq: 1000 BYE M24 SIP/2.0 200 OK Via: SIP/2.0/UDP 1.2.3.4:5060;branch=z9hG4bK543 From: Ada Lovelace k<sip:ada@language.org>;tag=65a3547e3 To: Charles Babbage <sip:babbage@analyticalsoc.org>;tag=9382 Call-ID: f6-32-9a-34-91-e7@analyticalsoc.org CSeq: 1000 BYE 10.2 SIP Call with Stateless and Stateful Proxies with Called Party Busy Figure 10.2 shows an example of a SIP with a stateless proxy server and a stateful proxy server. The call is not completed because called party is busy. The called user agent initially sends a 180 Ringing response but then sends a 600 Busy Everywhere response containing a Retry-After header to indi- cate that the call is being rejected. The stateful proxy returns a 100 Trying response to the INVITE, and also acknowledges the 600 Busy Every- where response with an ACK. The stateless proxy does not send a 100 Try- ing and forwards the 600 Busy Everywhere and the ACK sent by the caller user agent. Also note that the initial INVITE does not contain a message body. INVITE sip:schockley@transistor.org SIP/2.0 Via: SIP/2.0/UDP discrete.sampling.org:5060;branch=z9hG4bK5654 Call Flow Examples Stateless proxy Stateful proxy Shannon server server Schockley sampling.org 9.8.7.6 10.9.8.7 67.3.2.1 INVITE M1 INVITE M2 INVITE M4 100 M3 180 M6 180 M5 180 M7 600 M8 600 M10 600 M11 ACK M9 ACK M12 ACK M13 Figure 10.2 SIP call example with stateless and stateful proxies with busy called party. Max-Forwards: 70 From: Shannon <sip:shannon@sampling.org>;tag=cgdf4 To: Schockley <sip:shockley@transistor.com> Call-ID: adf8gasdd7f1d@discrete.sampling.org CSeq: 1 INVITE Contact: sip:Shannon@discrete.sampling.org> Date: Sat, 8 Jul 2000 08:23:00 GMT <Optional date header Content-Length: 0 <Optional Content