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Chapter 5 standards for multimedia communications

Chapter 5 standards for multimedia communications. 5.1 Introduction 5.2 reference models 5.3 standards relating to interpersonal communications 5.4 Standards relating to interactive applications over the internet 5.5 standards for entertainment applications. 5.1 introduction.

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Chapter 5 standards for multimedia communications

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  1. Chapter 5 standards for multimedia communications • 5.1 Introduction • 5.2 reference models • 5.3 standards relating to interpersonal communications • 5.4 Standards relating to interactive applications over the internet • 5.5 standards for entertainment applications

  2. 5.1 introduction • In this chapter we present an overview of the standards that have been defined for use with multimedia communication • A reference model is used for defined the various standards

  3. 5.2 reference models • The standards associated with the three types of application,show in figure5.1 • The functionality of each set of standards is as follows: • Application standards • Network interface standards • Internal network standards

  4. Figure5.1(a)

  5. Figure 5.1(b)(c)

  6. 5.2 reference models-5.2.1 • Tcp/ip reference model (figure 5.2) • Physical layer • Link layer • Network layer • Transport layer • Application layer

  7. Figure 5.2

  8. 5.2 reference models-5.2.2 • Protocol basics • The protocol to be used at each layer is chosen to meet the needs of a particular application/network combination • Protocol control information(PCI) • Protocol data unit(PDU) • Show figure 5.3

  9. Figure 5.3(a)

  10. Figure 5.3(b)

  11. 5.3 standards relating to interpersonal communications-5.3.1 circuit-mode networks • Circuit-mode network is show in figure 5.4 • Network interface standard • Transport layer • Multiplexer / demultiplexer • System control application • Audio and video codecs • Multipoint communications service(MCS)

  12. Figure 5.4

  13. Table 5.1

  14. 5.3 standards relating to interpersonal communications-5.3.1 circuit-mode networks-cont • H.320 • The H.320 standard is intended for use in end systems that support a range of multimedia application over an ISDN • Audio:G.711,G.722,G.728 • Video:H.261 • User data:T.120 • System control/call setup:Q.391 • Multiplexing:H.221

  15. 5.3 standards relating to interpersonal communications-5.3.1 circuit-mode networks-cont • H.324 • Over bit rate switched networks such as a PSTN • Video:H.261,H.263 • Audio:G.723.1,G.729 • User data:T.120 • Multiplexing • Total channel bandwidth is divided into a number of separate logical channels • Bit-oriented protocol ,the principles of which are shown in figure 5.5

  16. Figure 5.5

  17. 5.3 standards relating to interpersonal communications-5.3.1 circuit-mode networks-cont • Adaptation • In order to allow for the possibility of transmission errors being present in the received byte stream associated with each logical channel • The adaptation layer supports three difference schemes-AL1,2 and 3 • Multipoint conferencing:H.324 • System control :h.245 is concerned with the overall control of the end system

  18. 5.3 standards relating to interpersonal communications-5.3.1 circuit-mode networks-cont • H.321/H.310 • Intended for use with terminals that provide a range of multimedia application over a B-ISDN • H.322 • Intended for use with end systems that support interpersonal communication applications over a local area network(LAN)

  19. 5.3 standards relating to interpersonal communications-5.3.2 packet-switched networks • H.323 • Attached either to the same LAN or to different LANs • H.323 is intended for use with LANs that provide a non-guaranteed QoS • Figure 5.6 show structure

  20. Figure 5.6

  21. 5.3 standards relating to interpersonal communications-5.3.2 packet-switched networks-cont • Audio and video coding • Audio codec:either G.711 or G.728 • Video codec:either H.261 or H.263 • Call setup:H.323 gatekeeper can be used • Figure 5.7 two-party call setup procedure using an h.323 gatekeeper • Figure 5.8 H.323 multiplexing/ demultiplexing

  22. Figure 5.7

  23. Figure 5.8

  24. 5.3 standards relating to interpersonal communications-5.3.2 packet-switched networks-cont • Interworking • End system that are attached to a circuit-mode network is achieved. This is through H.323 gateway • Figure 5.9

  25. Figure 5.9

  26. 5.3 standards relating to interpersonal communications-5.3.2 packet-switched networks-cont • IETF • Early IETF provided a basic two-party telephony service between two IP hosts • Later IETF provided a more versatile facility supporting both multiparty conferencing and broadcast services • Signaling protocol • Session initiation protocol (SIP) • Sip provides services for user location,call establishment,and call participation management

  27. 5.3 standards relating to interpersonal communications-5.3.2 packet-switched networks-cont • Session description protocol(SDP) • When a user is invited to join in a call/session

  28. 5.3 standards relating to interpersonal communications-5.3.3 electronic mail • Internet mail • Figure 5.10 email over the internet • User agent(UA) • Message transfer agent(MTA) • Message store(MS) • Simple mail transfer protocol(SMTP) • Domain name server(DNS)

  29. Figure 5.10

  30. 5.3 standards relating to interpersonal communications-5.3.3 electronic mail-cont • MIME(multipurpose internet mail extensions) • RFC 822:email messages are written in English and are made up of just ASCII characters • Extensions to the basic format defined in RFC 822 were added.these are defined in RFC 2045 and are known as MIME

  31. 5.3 standards relating to interpersonal communications-5.3.3 electronic mail-cont • e-mail gateways • Show figure 5.11 • Two problem: • Format of the mail message is often different • The application protocol are also different • To overcome these problems,a device known as an email gateway is used,show figure 5.12

  32. Figure 5.11

  33. Figure 5.12

  34. 5.4 standards relating to interactive applications over the internet-5.4.1 information browsing • Figure 5.13 show information browsing

  35. figure 5.14

  36. 5.4 standards relating to interactive applications over the internet-5.4.2 electronic commerce • To send detail of your credit card in order to purchase • Figure 5.15 electronic commerce • Common gateway interface(CGI) • security

  37. Figure 5.15

  38. 5.4 standards relating to interactive applications over the internet-5.4.3 intermediate systems • Communication between the client and server is achieved through a networking device • Show figure 5.16 • Security gateway • Packet filtering • Proxy server

  39. Figure 5.16

  40. 5.4 standards relating to interactive applications over the internet-5.4.4 Java and JavaScript • Figure 5.17 • Applet • Virtual machine • Bytecode • Javascript • Embed java code into an HTML page directly

  41. Figure5.17

  42. 5.5 standards for entertainment applications –5.5.1 Movie/video-on-demand • Transmission format (figure 5.18) • Elementary streams • Packetized ES (PES) • System time clock(STC) • Pack • System clock reference(SRC)

  43. Figure 5.18

  44. 5.5 standards for entertainment applications –5.5.1 Movie/video-on-demand-cont • Distribution network • Figure5.19(a) show telephony company architecture • Figure5.19(b) show cable TV company architecture

  45. Figure 5.19

  46. 5.5 standards for entertainment applications –5.5.2 Interactive television • Base on MPEG-2 format • TV program multiplexing(a)PS and TS generation (b) TS format (figure 5.20) • System-level • Program allocation table(PAT) • Program map table(PMT) • Conditional access table(CAT)

  47. Figure 5.20

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