M (Presence and Instant version2, 92 Messaging), 199 programming SIP apps, 113 SMTP, 59 proposed standards TCP, 58 IETF, 50 TCP/IP, 56 SIP, 93 UDP, 58 Index provisional responses, SIP extensions, 166 SIP internetworking, 204 proxy servers, 103, 126 extensions, 210 calls, 151-157 gateways, 206 distribution, 129 high-capacity gateway, 209 forking, 104 low-capacity gateway, 207-208 group addresses, 104 message bodies, 211 stateful, 127-128 PINT, 213 stateless, 129 trunk signalling, 18-21 PSTN (Public Switched Telephone UNI, 18 Network), 2 X.25, 36 access signalling, 18 PUA (Presence User Agent), 200 analog transmission, 12 busy tones, 10 call connection process, 10 Central Battery systems, 9 DC and AC systems, 10 QoS (Quality of Service), 74 differences from Internet, 25 real-time services, 59 digital signalling systems, 17-18 real-time traffic transport, 70-71 digital transmission, 13 reason phrases, SIP responses, 117 audio codecs, 14 Record-Route headers, SIP requests, delay, 14-15 139-140 local loop, 15 redirect servers, 102 PCM, 14 registering user locations, 97 strengths, 14 REGISTER requests, 125 TDM, 15-16 registrars, 105 weaknesses, 14 reliability of the Internet, 26 DSS-1, 19 reliable delivery of provisional responses, DTMF tones, 18 SIP extensions, 166 early telephone systems, 9 repeaters, 14 FDM, 11 requests, SIP, 117, 132 in-band signalling, 11 ACK, 121-122 Local Battery systems, 9 BYE, 125 NNI, 18 CANCEL, 123-124 reliability, 26 Csec, 137-138 signal spectrum, 12 Index headers, 134 protocols, 65 Call-ID, 135 dense mode, 65 Contact, 136 sparse mode, 66 From, 138 packet headers, 32 Record-Route, 139-140 unicast, 62 Route, 139-140 virtual circuits, 33 Via, 142 RSVP (ReSerVation Protocol) INVITE, 119-120 PATH messages, 79 OPTIONS, 126 RESV messages, 78 REGISTER, 125 RTCP (Real-time Transport Control request line, 132 Protocol), 73 reservation merging, 76 RTP (Real-time Transport Protocol), 71, 91 responses, SIP, 116 RTSP (Real-Time Streaming Protocol), 87 format, 132 non-successful final, 146 reason phrases