on B., 9 versions, 91-92 SUBSCRIBE/MODIFY framework, Web sites, 221 instant messaging, 200 Dean Willis, 225 subscriber lines, 15 Henning Schulzrinne, 223 successful final responses, 148 IETF, 221, 223 supplementary services, ISUP, 24 RFCs, 221 switch delay, 7 SIP Forum, 226 switchboard operator, 4 SIP Forum Web site, SIP information, 226 switches, 4 SIP toolkit, 165. switching packets. See packet switching. See also 3G mobile systems. syntax, SDP session descriptions, 83-84 SIP working group, 48 SMTP (Simple Message Transfer Protocol), 59, 112 soft states, IP, 78 Sparse mode, multicast routing protocols, 66 TCP/IP (Transmission Control specifications, IETF, 50 Protocol/Internet Protocol), Internet SS7 (Signalling System 7), intelligence architecture, 56-58 inside network, 23-25 TDM (Time Division Multiplexing), SSPs (Service Switching Points), 25 15-16, 30 standards track RFCs, 50 telephone systems star topology, 4 access signalling, 18 state information storage, IP, 76 analog transmission, 12 stateful proxy servers, 127-128 busy tones, 10 stateless proxy servers, 129 call connection process, 10 statelessness, IP, 39 Central Battery, 9 status codes, SIP responses, 117-118 digital transmission, 13-18 STD subseries, IETF, 51 DSS-1, 19 STPs (Signalling Transfer Points), CCS, 21 DTMF tones, 18 BMT Element: BMT Title (if no parts setjust BMT Element in Bold FDM, 11 transmitting signals, 12-13 in-band signalling, 11 Transport layer Local Battery, 9 Internet, 56 NNI, 18 protocols, 58 signal spectrum, 12 SIP, 144 trunk signalling, 18-21 trunk signalling, 18-21 UNI, 18 TUP (Telephone User Part), 23 terminals, 6 text-based messages, 130 third generation mobile systems, 192-193 buddy lists, 199 circuit switched domains, 193 UACs (User Agent Clients), 116 instant messages, 199 UAs (User Agents), 98 IP multimedia domains, 193 automatic configuration, 172-173 network domains, 193 delivery-to-media tools, 100 packet-switched domains, 193 implementation, 100 presence information, 199 redirect servers, 102 roaming user sessions, 