AIMD (additive-increase, multiplicative-decrease),

Transcription

1 AW001-PerkinsIX 5/14/03 2:01 PM Page 397 INDEX A ACK (acknowledgement) Use with RTP retransmission, Use with TCP ACM (Association for Computing Machinery), 26 Active content, security of, 382 additive-increase, multiplicativedecrease (AIMD), , 303 Admission control, congestion and, 288 ADUs (application data units), 52, Advanced Encryption Standard (AES), 365, 375 Advertisement protocols, 62 AES (Advanced Encryption Standard), 365, 375 AH (Authentication Header), AIMD (additive-increase, multiplicative-decrease), , 303 Algorithms audio error concealment. See Error concealment, audio audio format conversion, 149 audio mixing, audio playout adaptation, 197 clock skew management, encryption, 365 FEC. See FEC (forward error correction) IPSec, 380 jitter compensation, 185 TCP-friendly rate control, video error concealment. See Error concealment, video video format conversion, 150 video playout adaptation, 198 AMR (Adaptive Multi-Rate) audio interleaving and, 250 loss-tolerant payload formats for, 87 partial checksums and, AMR-WB (Adaptive Multi-Rate Wideband) audio, 250 APP (application-defined packets), RTCP, 98, 118 application data units (ADUs), 52 Application layer, OSI reference model, 18 Application-level authentication, 377 Application-level encryption, Application-level framing, RTP design, Application-specific multiplexing, Applications data transport decisions, 52 GeRM, header compression and, TCP limitations for real-time applications, 47 ARPANET, 4 Association for Computing Machinery (ACM),

2 AW001-PerkinsIX 5/14/03 2:01 PM Page INDEX Asynchronous playout, 205 Atlantic Satellite Network (SATNET), 5 ATM (Asynchronous Transfer Mode), 355 Audio capture devices, decoding compressed media, distortion, 228 error concealment. See Error concealment, audio lack of congestion control standards for, 298 mixing, packet size, 37 payload formats, 60, playout point with silence suppression, playout point without silence suppression, quality measurements, RTP timestamp and, 154 separating from video, teleconferencing, 272 Audio redundancy coding, effect on playout buffer, limitations of, 271 overview of, packet format, use of, 272 Audio/Video networking early packet voice and video experiments, 4 5 Internet and, 5 7 ITU standards, 7 8 streaming A/V, 9 Audio/Video profile, See also RTP profiles Audio/Video transport, requirements in packet networks, RTP standard, 55 use of TCP, 47 use of UDP, Audio/Video Transport group, IETF, 10, 55, Authentication, firewalls and, 380 IPsec, 373, levels applied at, 377 RTP standard, 377 SRTP, 378 types of, Authentication Header (AH), Average packet loss, IP networks, B Bandwidth FEC impact on, redundant encoding and, 270 RTCP reporting interval and, 129 RTCP implementation problems and, session information variables and, 124 TCP probing available, TCRTP and, 347 Bidirectional optimistic mode, ROHC, 330 Bidirectional reliable mode, ROHC, 330 Book references, 395 Bridges, as one-to-one translator, 91 Buffer overflow attacks, Buffers audio mixing, for error correction, playout buffer, 166 delay due to TCP, 44 video playout, Bundling RTP packets, BYE (membership management), RTCP overview of, packets, 98, 165 reconsideration, C CAIDA (Cooperative Association for Internet Data Analysis), 26 Call control protocols, 10 Call setup protocols, 62 Canonical names. See CNAME (canonical names) Capture time, 152, 217

3 AW001-PerkinsIX 5/14/03 2:01 PM Page 399 INDEX 399 Capture-to-playout delay, receivers, 220 Cellular networks, performance characteristics, 40 Channel coding, overview of, 273 partial checksum and, reference picture selection, Checksums effects on header compression, in CRTP, , 326 in ROHC, 328 packet corruption and, partial checksum in channel coding, UDP, 43 Circuit emulation, Clock skew, 34, algorithms for managing, compensation strategies, 175 estimating, nonstationary skew, 179 packet send time vs. receive time, 171 playout calculation and, 174 Clocks See also Timestamps mapping RTP media clock to sender s reference clock, 164 media clock, RTP timing model and, synchronization of media streams, CNAME (canonical name) IP addresses and, 120 linking audio and video streams, 165 mapping SSRC to, 82, member identification by, 126 privacy and, SDES items and, Codecs (compression-decompression) audio, , 168, 300, 335 integrated with audio capture, 151 integrated with video capture, 151 interpolation of codec state, 241 layered coding and, 306 RTP standard and, 10 See also Payload Formats separating audio and video packets, speech, 195 video, 150, 168, 300 Collision detection, SSRC, 82 Comfort noise, 233 Components, RTCP, Compound packets, RTCP, Compressed RTP. See CRTP (Compressed RTP) Compression. See also Codecs (compressiondecompression); Header compression audio capture and, context, 200 CRTP, decoding audio, decoding video, ROHC, video capture and, video predictive coding, 242 Conferences, reference resources, Confidentiality encryption algorithms, 375 end-to-end encryption, IPsec, overview of, RTP specification, Secure RTP profile, Congestion bandwidth and, 253 denial-of-service attacks and, 381 detecting, need for controlling, Congestion avoidance, 292 Congestion collapse, Congestion control admission control and, 288 congestion collapse and, fair sharing of capacity, , 296 multicast, 306, Congestion control, Internet, detecting congestion, OSI layers and, 290 sliding receiver window, 290, 292 stop-and-wait protocols, TCP congestion windows, 291 throughput and, 295

4 AW001-PerkinsIX 5/14/03 2:01 PM Page INDEX Congestion control, multimedia, fair sharing of capacity, 296 layered coding, TCP and, TCP-friendly rate control, TCP-like rate control, traffic priority and, Congestion window, TCP, Context, compression, 200 Context, CRTP, Context, ROHC, Context identifiers, header compression, 322 Contributing source. See CSRC (contributing source) Control packets, RTP packet reception, Control protocols, 56, 62. See also RTCP (RTP control protocol) Cooperative Association for Internet Data Analysis (CAIDA), 26 Coordinated Universal Time (UTC), 213 Count field, RTCP header, 164 CRTP (Compressed RTP), compared with ROHC, compression/decompression, initialization and context, overview of, packet loss and, standards, Cryptography. See Encryption CSRC (contributing source), RTCP FEC packet, 257 participant database and, 127 RTP header, 83 See also Mixers Cumulative number of packets lost, 102 D DARTnet, 5 Data Encryption Standard (DES), 365, 373, 375 Data link layer, OSI reference model, 17, 19, 315 Data transfer packets. See Packets, RTP data transfer Data transfer protocol, RTP, 56 Decoding compressed media, See also Codecs (compression-decompression) audio mixing, audio playout, buffers, 166 overview of, playout and, 169 separating audio and video packets, 211 video playout, Delay since last sender report (DLSR), 104 See also Round trip time Denial-of-service attack, 381 Dependency reduction, video error concealment, DES (Data Encryption Standard), 365, 373, 375 Design philosophies, RTP, application-level framing design, end-to-end design, flexibility, 54 Dial-up modems, 319 Differentiated Services framework prioritizing traffic flows, 290, 298 QoS, separating audio and video packets and, 210 Digital sound, Directory memory access (DMA), Displays, refresh rate, 206 Distortion, audio, 228 Dither interval, DLSR (delay since last sender report), RTCP, 104. See also Round trip time DMA (directory memory access), DTMF tones, 60, 272 E E (Extension), FEC packet, 258 Early feedback mode, RTP retransmission, 280 Eavesdropping, preventing, 360, 376

5 AW001-PerkinsIX 5/14/03 2:01 PM Page 401 INDEX 401 ECMAScript, 382 item, SDES, Encapsulating Security Payload (ESP), 373, Encryption algorithms, 365 application-level, confidentiality algorithms, 375 coupling between packets and, 375 end-to-end, IP-level, 363 key exchange, 366 nontrivial nature of encryption code, 362 RTCP packets, 121, RTP data packets, End-to-end delay, 170, 172 End-to-end encryption, End-to-end principle header compression and, 340 RTP design and, Endpoints, Error concealment, audio, interleaving, interpolation of codec state, 241 measuring audio quality, model-based repair, 241 noise substitution, overview of, regenerative repair, 241 repetition, silence substitution, timescale modification, 241 waveform substitution, Error concealment, video, dependency reduction, interleaving, motion-compensated repetition, overview of, spatial and temporal repairs, 245 Error correction, channel coding, FEC. See FEC (forward error correction) implementation considerations, payload formats, 60 playout compensation and, retransmission, separating audio and video packets, 211 Error protection codes, packet reception, 164 Error resilience application level framing and, 52 multiplexing and, 342 payload headers and, 87 ESP (Encapsulating Security Payload), 373, Exploders, as one-to-many translator, 92 Extended highest sequence number, RTCP packets, 103 Extension (E), FEC packet, 258 Extension headers. See Header extensions F FEC (forward error correction), advantages/disadvantages, application-level framing and, 52 audio redundancy coding. See Audio redundancy coding coupling between packets and, 375 packet schemes, 260 parity FEC. See Parity FEC (forward error correction) Reed-Solomon codes, Feedback bidirectional and unidirectional, in ROHC, 330 modes, for RTP retransmission, packets, for RTP retransmission, 279 Fidelity, playout buffer and, 170 File Transfer Protocol (FTP), 17 Firewalls authentication and, 380 IPsec and, First-order compression state, ROHC, 329 Formats, packet audio redundancy, CRTP, GeRM,

6 AW001-PerkinsIX 5/14/03 2:01 PM Page INDEX parity FEC, retransmission, RTCP overview of, RTCP SR packets, RTCP RR packets, RTCP SDES packets, RTCP APP packets, 118 RTCP BYE packets, 117 RTCP compound packets, 100 RTP data transfer protocol, 70 Secure RTP SRTP, 367 SRTCP, 371 IPsec ESP, 374 AH, 379 IP, 20 UDP, 42 Formats, payload AMR (Adaptive Multi-Rate) audio, 87 audio, audio redundancy, 268 comfort noise, 233 coupling between packets and, 375 fragmentation and, 156 H.261 video, interframe coding and, 275 list of, 72 mapping to payload type, multiple formats, 75 multiple frames and, 88 MP3 See MPEG Audio Layer-3 (MP3), RTP, selecting, 74 static versus dynamic, ULP and, video, Forward error correction. See FEC (forward error correction) Forward reconsideration, RTCP, Fragmentation IPv4 support for, 37 MTU and, 89 playout compensation and, 181, 184 RTP packet generation and, Frames audio capture and, fragmentation of, interleaving and, 249 multiple, 88 packet reception and, 158 playout buffer and, 166 prerecorded content and, video capture and, Frequency repairs, video error concealment, 245 FTP (File Transfer Protocol), 17 Full header packets, CRTP, 322 G Gateways. See Routers Generic RTP Multiplexing. See GeRM (Generic RTP Multiplexing) GeRM (Generic RTP Multiplexing) application scenarios, concepts, future of, IETF and, 349 packet format, H H.245, session description, 73 H.261 video, H.320, 7 H.323 as call setup protocol, 62 ITU standards, 8 RTP specification in, 10, 55 H.332, 7 Header compression, applications and, CRTP. See CRTP (Compressed RTP) local implementation, 318 multiplexing and, overview of, patterns, principles, 320

7 AW001-PerkinsIX 5/14/03 2:01 PM Page 403 INDEX 403 robustness, ROHC. See ROHC (Robust Header Compression) RTP, 60 scenario for use of, 316 standards, 318 Header elements, RTCP packets, 98 99, 164 Header elements, RTP packets, contributing sources (CSRCs), 83 marker (M) bit, padding (P) bit, payload-specific, 157 payload type (PT) field, sequence number, size of, 315 synchronization source (SSRC), timestamp, version number, 85 Header extensions, RTP, Header fields, FEC packets, 257 Heterogeneity of networks, 41 HMAC-MD5-96, 380 HMAC-SHA-1, 378 HMAC-SHA-96, 380 HTML (Hypertext Markup Language), 18 HTTP (Hypertext Transport Protocol), 17 I IC (item count), RTCP packets, 99 IEEE b, wireless communication, 18 IETF (Internet Engineering Task Force) Audio/Video Transport group, 10, 55, Internet drafts, multimedia protocol stack, 11 RTP specification, 6, 55 standards, standards development cycle, IKE (Internet Key Exchange), 375, 380 Immediate feedback mode, RTP retransmission, 280 Initialization, of compression context CRTP, ROHC, 329 Input buffers, audio capture, Input Queues, separating packet reception from playout, Integrated layer processing, 166 Integrated Services Digital Network (ISDN), 7 Integrated Services framework see RSVP Integrity protection, HMAC-SHA-1, 378 IPsec and, 378 replay attacks and, 380 Interarrival jitter RTCP packets, RTP packets, 161 Interframe coding, 275 Interleaving coupling between packets and, 375 CRTP and, 335 for error concealment, playout compensation and, 184 Internet architecture of, 23 Audio/Video networking, 5 7 congestion control, OSI reference model and, Internet Engineering Task Force. See IETF (Internet Engineering Task Force) Internet Key Exchange (IKE), 375, 380 Internet Protocol. See IP (Internet Protocol) Internet Weather Report, 28 Interpolation of codec state, 241 Interpretation interval, ROHC, 332 Intranets, 39 IP addresses, 113 IP datagrams, 19 IP headers, 20 IP (Internet Protocol), abstraction provided by, IP-to-PSTN gateways, network layer and, 19 routers and, services of, TCP and UDP and, 22 IP-level authentication, 377

8 AW001-PerkinsIX 5/14/03 2:01 PM Page INDEX IP-level security. See IPsec (IP Security) IP multicast benefits of, 48 packet loss and, IP networks audio/video transport over, 9 average packet loss, heterogeneity of, 41 intranets, 39 measuring performance, 25 26, multicast sessions, network technologies and, packet corruption, packet duplication, packet loss patterns, packet sizes, 37 packet transit time, performance characteristics, IP routers, 18 IP-to-PSTN routers, IPsec (IP Security), algorithms, 380 authentication, 373, confidentiality, 373 ESP, firewalls, IKE, 375 modes of operation, IPv4 fragmentation support, 37 header format, 20 ID field, 322, 324, 336 IPv6, 20 compression of, 321 ID field, lack of, 322 ISDN (Integrated Services Digital Network), 7 Item count (IC), RTCP packets, 99 ITU standards Audio/Video networking, 7 8 measuring audio quality and, 228 teleconferencing protocols, 11 See also H.245, H.320, H.323, and H.332 J Java applets, 382 Jitter buffers for removing, 166 compensating playout calculation for, interarrival jitter in RTCP packets, 103 Interarrival jitter in RTP packets, 161 packet transit time and, 33 randomness of network-induced, 186 triggers for adaptation, Join experiments, Journal papers, reference resources, K Key exchange, 366 L L2TP (Layer Two Tunneling Protocol), , 347 Last sender report (LSR) timestamp, RTCP, 104 Latency See also Playout buffer interleaving and, 250 payload data and, 89 Layered coding, congestion control, Least-significant bit encoding (LSB), ROHC, Length field, RTCP packets, 99 Length recovery, FEC packets, 258 Lip synchronization, accuracy of, mapping RTP media clock to sender reference clock, 164 overview of, receivers, senders, Listening tests measuring audio quality and, noise substitution and, 233 repetition and, 237 silence substitution and, 231 LOC item, SDES, 114

9 AW001-PerkinsIX 5/14/03 2:01 PM Page 405 INDEX 405 Local implementation, header compression, 318 Local timeline, mapping playout calculation to, Loss fraction, 103, , 305 Loss packet rates, LSB (least-significant bit encoding), ROHC, LSR (last sender report) timestamp, RTCP, 104 M Marker (M) bit, RTP header, 83 84, 168 Mask, FEC packet, 258 Matrices, interleaving, Maximum transmission unit. See MTU (maximum transmission unit) Mbone tools, 6 7 Mean Opinion Score (MOS), Media capture, audio capture and compression, prerecorded content, video capture and compression, Media clocks synchronizing with reference clocks, timestamps and, Media decoders, See also Decoding compressed media Media frames. See Frames; Media, real-time, Media streams confidentiality of, 121 encrypting, header fields and, 328 mixing, 201 multiplexing, synchronization. See Lip synchronization Media transport layer, 10 Media transport standards, 8 Membership management. See BYE (membership management), RTCP Mergers, as one-to-many translator, 92 Message authentication, 377, 378 Metrics, packet loss, 26 MIME (Multipurpose Internet Mail Extensions), 18, 59 Mapping to payload type, Mixers overview of, RTP support for, 57 security of, Mixing audio, Mixing media streams, 201 MMX (Multimedia Extensions), 203 Model-based repair, 241 Modes of operation RTP retransmission, ROHC, Monitoring packet reception, 164 MOS (Mean Opinion Score), Motion-compensated repetition, MPEG Audio Layer-3 (MP3); See also Formats, payload interleaving and, 249 loss-tolerant payload formats for, 87 MPEG B frames, 335 MTU (maximum transmission unit) fragmentation and, packet sizes and, 37 payload data and, 89 Multicast conferencing, 9 congestion control and, 306, sessions, IP networks, Multimedia congestion control, streaming, 6 Multimedia Extensions (MMX), 203 Multimedia protocol stack, Multimedia synchronization. See Lip synchronization Multiplexing, advantages/disadvantages, application-specific, compared with bundling, GeRM,

10 AW001-PerkinsIX 5/14/03 2:01 PM Page INDEX header compression and, RTP, 61 TCRTP, telephony specific, Multipurpose Internet Mail Extensions (MIME), 18, 59 Mapping to payload type, N NACK (negative acknowledgement), NAME item, SDES, 113 NAT (Network Address Translation) authentication, 380 IP addresses, 113 IPsec and, RTP awareness and, 120 National Laboratory for Applied Network Research (NLANR), 26 Negative acknowledgement (NACK), Network Address Translation. See NAT (Network Address Translation) Network layer, OSI reference model, 17, 19 Network technologies, IP networks, Network Time Protocol (NTP), , 180, 213 Network traffic congestion control and, 287, measurements, 24 multimedia and congestion collapse, 289 patterns, 25 prioritizing, Network Voice Protocol (NVP), 4 5 NLANR (National Laboratory for Applied Network Research), 26 Noise substitution, NOTE item, SDES, 114 NTP (Network Time Protocol), , 180 NTP timestamp, 108, 213 Null termination, SDES, NVP (Network Voice Protocol), 4 5 O Open standards, vs. proprietary solutions, 4 OSI reference model, communication between layers, 18 congestion control and, 290 difficulty of placing RTP in, 57 Internet and, IP and, layers of, presentation protocols, 22 protocol layering, session protocols, 22 transport protocols, 22 Out-of-order packets, 192 P P (padding) bit. See Padding (P) bit Packet formats. See Formats, packet Packet generation, RTP, fragmentation, overview of, payload-specific headers, 157 timestamps, Packet loss cumulative number of RTCP packets, 102 effects on CRTP, effects on ROHC, effects on TCRTP, 348 parity FEC and, 261 patterns, 29 30, 41 QoS and, recovering from, retransmission and, ULP, Packet networks A/V transport requirements, voice and video experiments on, 4 5 Packet Radio Network, 4 5 Packet reception, RTP, control packets, data packets, monitoring, 164 overview of, separating from playout, 162 Packet type (PT), RTCP, 99

11 AW001-PerkinsIX 5/14/03 2:01 PM Page 407 INDEX 407 Packet voice experiments, 4 5 Packets average packet loss, corruption, 31 32, 41 duplication, 30 31, 41 formats. See Formats, packet reliable delivery, 46 retransmission, 183 size, 37, 124, 129 transit times, 32 37, validation, Packets, RTCP application-defined, 118 BYE, compound, cumulative number of lost, 102 encrypting, 121 extended highest sequence number, 103 formats, loss packet rates, packing issues, receiver report, sender report, source description, timing rules, transmission rules, transport of, 97 types of, 96 validation, Packets, RTP data transfer compensating playout calculation for packet reordering, 192 contributing sources (CSRCs), 83 format of, 70 fragmentation, header elements, 71 header extensions, marker (M) bit, padding (P) bit, parts of, 70 payload data, payload headers, payload type (PT) field, reception, sequence number, synchronization source (SSRC), timestamp, version number, 85 Packing rules, compound RTCP packets, Padding (P) bit RTCP header, 98 RTCP implementation, 142 RTP header, Parity FEC (forward error correction) overview of, packet format, playout compensation and, 182 recovering from packet loss, redundant audio and, 272 unequal error protection, use of, Parsing SDES packets, , 165 Participant database, incorrect scaling, 141 member identification, 126 participant validation and, 127 per-participant data structure, receiver-specific information in, 164 receivers maintenance of, 158 removing participants, 128 reporting interval and, session variables, Patterns header compression, packet loss, 29 30, 41 Payload data, Payload formats. See Formats, payload Payload headers audio redundancy, FEC packet, 258 RTP data transfer packet, RTP packet generation and, 157 Payload type (PT) field mappings, 58, 71 recovery, FEC packet, 258

12 AW001-PerkinsIX 5/14/03 2:01 PM Page INDEX RTCP header, 99 RTP header, static vs. dynamic assignment, Per-flow validity checks, 90 Per-packet validity checks, 90 Performance TCRTP, wireless networks, 40 Performance, IP networks average packet loss, characteristics, measuring, 25 26, multicast sessions, network technologies, packet corruption, packet duplication, packet loss patterns, packet sizes, 37 packet transit time, PHONE item, SDES, 114 Phonemic restoration, 233 Physical layer, OSI reference model, 17, 19 Pitch cycles, speech patterns, 234 Plain-text attacks, 121 Playout buffer, clock skew compensation, data structures in, 167 fidelity vs. delay, 170 jitter compensation, mapping playout calculation to local timeline, overview of, packet reordering compensation, 192 playout time calculation, route change compensation, sender behavior compensation, separating audio and video packets, 211 separating packet reception from playout, 162 Playout point adaptation audio with silence suppression, audio without silence suppression, overview of, 192 video, Playout synchronization. See Lip synchronization Playout time, receivers, 220 Ports RTCP data, 97 RTP data, 97 TCP and UDP, 22 PPP multiplexing, , 347 Predictive coding limitations of, video loss concealment, 242 Prerecorded content media capture and, RTP timestamp and, 154 Presentation layer, OSI reference model and, 18 Presentation protocols, 22 PRIV items, SDES, 114 Privacy, , Protocol layering, OSI reference model, PSTN (Public Switched Telephone Network), PT (payload type). See Payload type (PT) field Public networks, 39 Public Switched Telephone Network (PSTN), Q QoS (quality of service) IP networks and, multiplexing and, 342 protocols, separating audio and video packets and, 210 See also Differentiated Services Framework and RSVP. R Random number generators, SSRC, 82, RAP (Rate Adaptation Protocol), 299 Rate control audio and video, 300 TCP-friendly, TCP-like,

13 AW001-PerkinsIX 5/14/03 2:01 PM Page 409 INDEX 409 Real-time media, Receive window, TCP, 291 Receiver reports. See RR (receiver reports), RTCP Receivers. See also Packet reception, RTP behavior of, 13 14, capture time determination, 217 capture-to-playout delay, 220 clock skew and, control packet reception, data packet reception, error concealment techniques and, , 247 error correction implementation, FEC packets and, 261 identifying media streams for synchronization, 216 lip synchronization, 218 multithreaded, 163 playout time determination, 220 sender behavior compensation, 181 synchronization adaptation, synchronization delay determination, Reconsideration, RTCP BYE reconsideration, forward reconsideration (step join), reverse reconsideration (step leave), Recovery process, FEC packets, Redundant audio. See Audio redundancy coding Reed-Solomon codes, Reference clocks, synchronizing with media clocks, Reference picture selection, channel coding, Reference resources, for this book, books, 395 conferences and journal papers, IETF drafts, IETF standards, other standards, Refresh rate, displays, 206 Refresh state, ROHC, 329 Regenerative repair, audio error concealment, 241 Reliable delivery, packets, 46 Repetition audio error concealment, motion-compensated in video, Replay protection, 380 Reportee SSRC, 102 Reporting interval, RTCP, lack of randomization in, 142 between packets, 96 Request for comments (RFCs), See also Standards ReSerVation Protocol. See RSVP (ReSerVation Protocol) Retransmission, RTP, applicability of, inefficiencies, 282 modes of operation, overview of, packet format, packet playout buffer, 183 timing rules, Retransmission, TCP, Reverse predicted video frames, 335 Reverse reconsideration, RTCP, RFCs (request for comments), See also Standards Robust Header Compression. See ROHC (Robust Header Compression) Robustness. See Congestion control; Error concealment; Error correction Robustness and compression efficiency, ROHC, Robustness, header compression, ROHC (Robust Header Compression), compared with CRTP, modes of operation, overview of, robustness and compression efficiency, standards, 318

14 AW001-PerkinsIX 5/14/03 2:01 PM Page INDEX states of operation, Round-trip time calculation, 164 packet playout buffer and, 183 RR data and, See also End-to-end Delay Route changes, playout compensation and, Routers congestion control and, 289 IP, 18, IP-to-PSTN, QoS and, 64 RR (receiver reports), RTCP data interpretation, packet format, round-trip calculation and, 164 RTCP packet types, 97 RSVP (ReSerVation Protocol) prioritizing traffic flows, 290, 298 QoS and, 63 separating audio and video packets and, 210 RTCP (RTP control protocol). See also Packets, RTCP application-defined packets, 118 BYE packets, BYE reconsideration, common implementation problems, components of, compound packets, forward reconsideration, membership control, overview of, packet formats, packet packing issues, packet transport, 97 packet type limitations, 58 packet validation, participant database, privacy, receiver report packets, reconsideration, 141 reference clock, 213 reporting interval, reverse reconsideration, security, sender report packets, source description packets, timing rules, transmission rules, RTP data transfer protocol, CSRCs, 83 header elements, 71 header extensions, marker (M) bit, mixers, overview of, 56 packet format, 70 packet validation, padding (P) bit, payload data, payload formats, 59 payload headers, payload type (PT) field, sequence number, sessions, SSRC, timestamp, translators, version number, 85 RTP-over-TCP encapsulation, 298 RTP (Real-time Transport Protocol), introduction, 9 14 application-level framing design, bundling packets, design philosophies, development of, 6 end-to-end principle in design, features, 9 10 flexibility of, 54 future standards, 65 header compression, 60 limitations of, 57 multiplexing, 61

15 AW001-PerkinsIX 5/14/03 2:01 PM Page 411 INDEX 411 payload formats, related standards, 10 11, RTP profiles, 58 59, 71-74, 81, 84 RTP receivers, RTP senders, specification, RTP receivers. See Receivers RTP senders. See Senders RTP timestamp. See Timestamps, RTP RTSP (Real-Time Streaming Protocol) as call setup protocol, 62 key exchange and, 366 normal play time in, RTP-over-TCP encapsulation, 298 streaming A/V, 9 RTT (round-trip time), See also Round-trip time S SAP (Session Announcement Protocol), 6 7, 62 SATNET (Atlantic Satellite Network), 5 Saturating addition, audio mixing, SDES (source destination), RTCP buffer overflow attacks and, parsers, item types, mapping SSRC to CNAME, overview of, packet format, packet reception, 165 RTCP packet types, 98 text security, SDP (Session Description Protocol) development of, 7 overview of, 63 RTP payload formats and, 59 payload type mapping using, Second-order compression state, ROHC, 329 Secure RTP profile. See SRTP (Secure RTP) profile Security, active content and, 382 authentication, confidentiality. See confidentiality denial-of-service, 381 mixers and, overview of, privacy, replay protection, 380 RTCP, SDES text items, translators and, Security parameter index (SPI), 373 Sender reports. See SR (sender reports), RTCP Senders behavior, 11 12, clock skew and, clock synchronization, congestion detection, error concealment techniques and, 247 error correction, 251, 285 FEC and, 252, octet count, 110 packet count, 110 playout calculation and, source synchronization, Sequence number, FEC, 258, 262 Sequence number, RTCP, 103 Sequence number, RTP, functions of, 75, initial values of, 77 wrap-around counters and, Serial links, CRTP, 319 Session Announcement Protocol (SAP), 6 7, 62 Session description protocols, 63. See also SDP (Session Description Protocol) Session initiation, key exchange, 366 Session Initiation Protocol. See SIP (Session Initiation Protocol) Session layer, OSI reference model, 17 Session protocols, 22 Sessions, RTP, defined, 67 types of, 69 unicast and multicast, 68 Signal-to-noise ratio, 228

16 AW001-PerkinsIX 5/14/03 2:01 PM Page INDEX Silence substitution, audio error concealment, Silence suppression audio with, audio without, Simple Mail Transfer Protocol (SMTP), 17 Simulcast, 307 SIP (Session Initiation Protocol) as call setup protocol, 62 development of, 7 key exchange and, 366 as replacement for H.323, 7 Sliding receiver window, congestion control, 290, 292 Sliding window protocols, 290 Slow-start algorithm, TCP, 304 SMTP (Simple Mail Transfer Protocol), 17 SONET (Synchronous Optical Network), 355 Sound. See Audio Source destination. See SDES (source destination), RTCP Source origin authentication, 377, 378 Spatial repairs, video error concealment, 245 Specification, RTP, 55 57, Speech codecs, 195 measuring audio quality and, 228 phonemic restoration, 233 pitch cycles, 234 repetition repair techniques, talk spurts, waveform substitution, SPI (security parameter index), 373 Spikes, packet transit time, 35, SR (sender reports), RTCP data interpretation, 110 mapping media clock to sender reference clock, 164 NTP timestamp and, 108 overview of, 107 packet format, packet variables, 125 round-trip calculation and, 164 RTCP packet types, 97 sender s packet count, 110 SRTP (Secure RTP) profile, AES as default for, 368 AES counter mode, 369 AES f8 mode, authentication, 378 encryption process with, payload encryption, RTCP packets, RTP packets, senders and receivers and, 368 SSRC (synchronization source) associating sources with media time base, 214 FEC packet, 257 mapping CNAME to, 82 member identification by, 126 nonrandom, 353 RR (receiver reports) and, RTP header, ST (Stream Protocol), 5 Standard deviation, jitter compensation, 187 Standards future development, 65 IETF, NIST, RTP related, 10 11, State information, 322 States of operation, ROHC, Step join, RTCP reconsideration, 134 Step leave, RTCP reconsideration, Stop-and-wait protocols, Stream Protocol (ST), 5 Symmetric algorithms, Synchronization. See also Lip synchronization accuracy of, adaptation in receivers, delay in receivers, Synchronization source. See SSRC (synchronization source) Synchronous Optical Network (SONET), 355

17 AW001-PerkinsIX 5/14/03 2:01 PM Page 413 INDEX 413 T T1 lines, 355 Talk spurts, audio playout adaptation, TCP-friendly rate control, TCP/IP OSI reference model and, TCP-like rate control, TCP (Transmission Control Protocol) congestion collapse and, 289 congestion control algorithms, 290 congestion windows, 291 fair sharing of capacity, features, 44 IP and, 22, 43 limitations for real-time applications, 47 multimedia congestion control and, packet loss and, 25 reliability at expense of timeliness, 52, 298 slow-start algorithm, 304 as transport protocol, TCRTP (Tunneling Multiplexed Compressed RTP), concepts, IETF Audio/Video group and, implementing, performance, protocol stack, 343 transparency of interface, 346 TDM (Time Division Multiplexing), 355 Telephony multiplexed, unicast voice, 54 Temporal repairs, video error concealment, 245 TESLA (Timed Efficient Stream Loss-tolerant Authentication), 378 Throughput congestion control and, 295 variations in, 295 Time Division Multiplexing (TDM), 355 Timed Efficient Stream Loss-tolerant Authentication (TESLA), 378 Timescale modification, audio error concealment, 241 Timestamps FEC packet, 258 LSR timestamp, 104 NTP timestamp, Timestamps, RTP, calculations, continuity of, 80 duplication of, function of, 78 initial values of, 78 NTP timestamp and, 109 packet generation and, playout calculation and, 173 synchronizing media clocks with reference clocks, 213 Timing model, RTP, Timing rules retransmission, RTCP, TOOL item, SDES, 114 Traffic. See Network traffic Transcoders, as one-to-one translator, Transit time, packets, calculating variance in, 103 factors effecting, jitter as measurement of, 33 measuring, periodicity in, 37 spikes, 35, Translators classes of, overview of, 91 RTP support for, 57 security, Transmission FEC and, 252 problem of discontinuous, 305 RTCP rules, , Transmission Control Protocol. See TCP (Transmission Control Protocol) Transport layer, OSI reference model, 17, 210

18 AW001-PerkinsIX 5/14/03 2:01 PM Page INDEX Transport mode, IPsec, Transport protocols OSI reference model and, 22 real-time media and, 46 TCP, UDP, Triple DES, 365 Troubleshooting RTCP implementation, Tunnel mode, IPsec, Tunneling, See also TCRTP (Tunneling Multiplexed Compressed RTP) Tunneling Multiplexed Compressed RTP. See TCRTP (Tunneling Multiplexed Compressed RTP) U UDP checksum compression efficiency and, disabling, 273 unpredictable header fields and, 329 UDP (User Datagram Protocol) as basis of RTP, 46 header, 42 IP and, 22, RTP sitting on top of, 56 standard RTP ports, 97 ULP (unequal layered protection), Unicast voice telephony, 54 Unidirectional mode, ROHC, 330 User Datagram Protocol. See UDP (User Datagram Protocol) User names, 120 UTC (Coordinated Universal Time), 213 UTF-8, 116 V Validity checks encryption confirmation, 365 RTCP packets, RTP packets, 90 Version number (V field) RTCP header, 98 RTP header, 85 Video. codecs, 168 conferencing, 5 7 decoding compressed media, error concealment. See Error concealment, video lack of congestion control standards for, 298 packet size, 37 payload formats, 60, playout point, RTP timestamp and, 154 treating separately from audio, Virtual private networks (VPNs), 344 Voice circuit emulation, 356 Voice-over-IP, 348 VPN (virtual private networks), 344 W W-LSB (window-based least-significant bit) encoding, ROHC, Waveform substitution, audio error concealment, Web browsers, 18 White noise, 231 Wideband Satellite Network, 5 Window-based least-significant bit (W-LSB) encoding, Wireless networks IEEE b, 18 performance characteristics, 40 Wiretaps, 376 Wrap-around counters, X XOR operation, parity FEC, ndwid