 caller preferences, 177-179 digital transmission, 13 COMETs, 174-176 distribution design guidelines, 163 SIP proxy servers, 129 event notification framework, 179-180 SIP sessions, 95 instant messaging, 171, 200 distribution trees, dense mode multicast method semantics, 164 routing protocols, 66 mid-session transactions, 169 draft standards, IETF, 50-52 multiple message bodies, 170 DTMF (Dual Tone Multi-Frequency) negotiation, 160-162 tones, 18 peer-to-peer relationship, 163 DVMRP (Distance Vector Multicast Routing PRACK requests, 168 Protocol), 66 provisional responses, 166 dynamic routing, datagrams, 35 PSTN-to-SIP internetworking, 210 reliable delivery of provisional responses, 166 sending commands, 186 sessions end-system intelligence transfers, 184 IP connections, 38 type independence, 164 SIP, 109 third-party call control, 181-182 Index high availability, IP connections, 39 high capacity gateways, PSTN-to-SIP FAQs, SIP-related, 225 internetworking, 209 FDM (Frequency Division history of SIP, 90 Multiplexing), 11-12, 30 HTTP, 56, 110 filters, FDM, 12 final call calendar, SIP RFCs, 225 first analog telephone systems, 9 forking, SIP proxy servers, 104 formats, SIP messages, 130-133 From headers, SIP requests, 138 Internet Activities Board, 46 full-mesh topology, 3 Internet Architecture Board, 47 ICB (International Cooperation Board), 46 ICCB (Internet Configuration Control Board), 46 IESG (Internet Engineering Steering gateways, PSTN-to-SIP internetworking, 206 Group), 47-49, 56 high capacity, 209 IETF (Internet Engineering Task Force), 47 low capacity, 207-208 BCPs, 51 group addresses, 102-104 BOF meetings, 49 GSM (Global System for Mobile), 19, 26 drafts guaranteed services, IP, 75 naming conventions, 52 standards, 50 informational RFCs, 51 Internet drafts, 52 non-standards track, 51 headers, 31 proposed standards, 50 routing packets, 32 protocol design guidelines, 42-44 SIP requests, 134 specifications, 50 Call-ID, 135 standards track RFCs, 50 Contact, 136 STD subseries, 51 toolkit, 42, 106 Csec, 137-138 We