1. Integrating Voice, Video, and Data
Chapter 10

2. Learning Objectives Explain analog and digital video technologies
Describe audio file technologies
Explain audio and video sampling
Describe Voice over IP
Assess bandwidth and throughput on a network
Explain how multimedia transmissions work
Design LANs and WANs for multimedia applications
Discuss multimedia issues of the future

3. Video Technologies Roots in analog TV
Analog and digital video technologies
Main video technologies used on computers
Audio Video Interleave (AVI)
Moving Pictures Expert Group (MPEG)
Fractal image

4. Analog Video Primarily associated with television
Television broadcast standards
National Television Standards Committee (NTSC)
525 vertical scan lines; 30 frames per second
Phase alternation line (PAL)
625 vertical scan lines; 25 frames per second
System Electronique Couleur Avec Memoire (SECAM)

5. Digital Video Commonplace on the Internet Increased distances
Sharper images
Network video transmissions involve several technologies; digital television uses one (MPEG-2)

6. Video Compression Technologies
AVI
Interleaves video and audio data to be reproduced as short clips
MPEG
Standard set by the MPEG within the ISO
Fractal image compression
Uses properties of fractals, duplicated images, and mapping to compress frames

7. Video Compression Techniques Used by MPEG
Lossy compression
Predicted encoding
Bidirectional interpolation

8. Predicted Encoding

9. Bidirectional Interpolation

10. MPEG Levels

11. MPEG Video Playback Options
Store on server for clients to download as a file and play using MPEG player software
Streaming the file over a network link

12. Audio File Technologies
Algebraic-Code-Excited Linear Prediction (ACELP)
Audio Code Number 3 (AC-3), which is Dolby digital surround sound
Adaptive Differential Pulse Code Modulation (ADPCM)
Audio Interchange File Format (AIFF)
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13. Audio File Technologies
Global System for Mobil Communication (GSM)
Interchange File Format (IFF)
Musical Instrument Digital Interface (MIDI)
MPEG-1 Audio
MPEG-2 Audio
MPEG-4 Audio
MPEG-7 Audio
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14. Audio File Technologies
Open Document Architecture Audio Content Architecture (ODA ACA)
Pulse code modulation (PCM)
Sub-band adaptive differential pulse code modulation (SB-ADPCM)
Waveform audio file format (WAV)

15. Audio File Technologies That Are Transported Over Networks
ACELP
Used in media player
MPEG
Used in many diverse kinds of applications
WAV (particularly PCM U-law)
Used to play music over the Internet

16. Audio and Video Sampling
Samples of an analog signal taken at specific intervals construct a digital signal
Type of sampling technique influences the quality of the signal

17. Popular Uses of Audio and Video Technologies
Internet radio and downloading music files
Audio and video conferencing
Online courses and seminars
attachments
Local and national news broadcasts

18. Growth Trends for Audio and Video Technologies
Telephone messaging services
Seminars
Movies
Live out-of-classroom help from teachers
Interviews
Physician training about pharmaceutical products
Integration of telephone, TV, computer, and stereo
Wireless, handheld audio/video devices for visitors to a new city

19. Voice over IP (VoIP)
Provides telephony communications over an IP network
Used by some companies as an alternative to PBXs, PAXs, and PABXs

20. Devices on a VoIP Network
Telephone device
Converts voice sounds into binary, then into IP packets
Call processor or call server
Sets up and terminates calls
Manages a calling session
Translates telephone numbers or IDs into IP addresses
Specialized gateway
Converts IP packetized voice data into a signal that can be transmitted over a PSTN

21. Widely Used VoIP Standards
ITU H.323
Session Initiation Protocol (SIP)
Media Gateway Control Protocol (MGCP)/ MEGACO/H.248

22. ITU H.323 Outlines several types of devices for voice communications
Used with several accompanying standards for compression/decompression (codec) and voice communications handling

23. SIP Signaling protocol created by IETF
Used to start or stop a VoIP communications session
Uses commands modeled after HTTP
Uses URLs for addressing
Advantages
Can be used over the Internet or on an IP LAN, MAN, or WAN
Can be used with H.323 systems

24. MGCP/MEGACO/H.248
Designed to handle translation of an audio signal to a VoIP network
Relatively low overhead; uses UDP for audio communications over an IP network
Compatible with networks that use SIP

25. Assessing Bandwidth and Throughput
Transmission capacity of a communications medium
Typically measured in bits per second (data) or hertz (some data, voice, and video)
Determined by maximum minus minimum transmission capacity
Throughput
Amount of traffic passing through given point on network at given time

26. Determining Download Time for a Single File
Download time in seconds = file size in bytes * 10 /connection speed in bps

27. Factors That Affect Bandwidth and Throughput
File compression and file format compatibility
Synchronization
Latency
Jitter

28. File Compression and File Format Compatibility
Reduces size of a normal file by using techniques to remove redundant information or blank areas in file’s structure

29. Synchronization
Ensures all constituent pieces are assembled and played in the right order
Most reliable with adequate bandwidth

30. Synchronization

31. Latency
Time it takes for networked information to travel from transmitting device to receiving device
Influenced by:
Transmission delay
Propagation delay
Processing delay
Store-and-forward or switching delay

32. Jitter Presence of variable latency on a network
Causes evident reproduction errors
Clicks or pops in audio playback
Jerky or delayed response in video

33. How Multimedia Transmissions Work in LANs and WANs
Typically occur between two devices (sender and receiver) with a LAN, WAN, or both in between
Different methods
Using network resources (eg, routers)
Creating transmissions that generate relatively more network traffic

34. Transmission Types
Unicast
Broadcast
Multicast

35. Unicast Transmissions
Description
Limitations
One copy of each frame or packet is sent to each destination point
Difficult to scale up multimedia applications for increased numbers of users
If many users, traffic volume is high and requires high bandwidth

36. Unicast Transmissions

37. Broadcast Transmissions
Description
Limitations
One copy of each frame or packet is sent to all points on a network, regardless of whether or not a node has requested it
If not filtered by internetworking devices, multimedia broadcast traffic can produce even more load on a network than unicasts, because it potentially goes to more destinations

38. Broadcast Transmissions

39. Multicast Transmissions
Description
Limitations
Server divides users who request certain applications into groups
Each data stream of frames or packets is a one-time transmission that goes to multiple addresses
More difficult to develop applications to use multicasting, but the payoff in improved network control and traffic patterns is well worth the effort

40. Multicast Transmissions

41. Multimedia Transmissions
Same application under different transmission methods
Role of Internet Group Management Protocol (IGMP)
Additional Protocols to Accommodate Multicasting
Distance Vector Multicast Routing Protocol (DVMRP)
Multicast Open Shortest Path First Protocol (MOSPF)
Protocol Independent Multicast (PIM)

42. DVMRP Works with RIP to determine:
Which workstations are subscribed to multimedia multicasts
Fewest hops to a particular router on a network
Route to take to reach a particular router

43. MOSPF
Works like OSPF in finding the shortest path from source to destination for multicast transmissions

44. PIM
Compatible with networks that use OSPF or RIP as their main routing protocol

45. Protocols with Real-Time Streaming Multicasts
Real-Time Protocol (RTP)
Multicast protocol developed for real-time multimedia applications
Real-Time Transport Control Protocol (RTCP)
Works with RPT to provide specific controls over multicast transmissions
Provides management information

46. Applications and Internetworking Devices
Resources Reservation Protocol (RSVP)
Used on TCP/IP-based networks
Enables an application to reserve computer and network resources it needs (bandwidth, buffers, maximum burst, classes of service)
Dynamically allocates resources as demands increase or decrease
Also know as the Resource Reservation Setup Protocol

47. RSVP

48. Making LANs and WANs Accommodate Multimedia Applications
Redesigning legacy networks for multimedia applications
Deploying high-speed Ethernet on multimedia-based LANs
Designing WANs that carry multimedia applications with ease

49. Redesigning a Legacy Network
Add switches and routers

50. Redesigning a Legacy Network

51. Redesigning a Legacy Network

52. Combining Fast Ethernet and Gigabit Ethernet

53. WAN Designs to Accommodate Multimedia
Match WAN to speed and application requirements of the connected LANs

54. Reducing WAN Costs and Increasing Performance
Schedule WAN usage around application use
Deploy multiple video servers at different sites throughout the LAN/WAN

55. Deploying Multiple Video Servers

56. Vendor Features That Increase WAN Performance
Snapshot routing
IPX/SPX spoofing
Bandwidth on demand

57. Multimedia Issues for the Future
Network-based computer instruction
Video conferencing
Streaming applications

58. Chapter Summary Analog and digital video technologies
Audio file technologies
Audio and video sampling
Integrating voice, video, and data on a network
Voice over IP (VoIP)
How to assess bandwidth and throughput on a network
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59. Chapter Summary
Packet and frame transmission techniques for integrated multimedia applications
How to design LANs and WANs to handle multimedia traffic
Issues that will affect how multimedia is transported in the future