Download - Protocol Engineering and Technology Unit

Multimedia Communications
Prof. Pallapa Venkataram,
Electrical Communication Engineering,
Indian Institute of Science,
Bangalore – 560012, India
E0262 - Multimedia Communications
Objectives
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To know the networking evolution.
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To understand the network types.
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To discuss multimedia requirements in the communication
systems.
To understand the basics of a multimedia communication
system.
To illustrate multimedia networks.
To know the Internet protocol suite for multimedia
communications.
E0262 - Multimedia Communications
Networking Infrastructure Evolution
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Network deployment issues
E0262 - Multimedia Communications
Network Topologies Evolution
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LAN
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Linear topology
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Star-wired
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Multisegment
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Backbone-connected
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Switched-backbonet
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WLAN
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WAN
E0262 - Multimedia Communications
Multimedia Requirements
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To develop schemes for multi-access networks which can
provide performance guarantees.
To develop a distribute route-selection strategy for point-topoint networks.
Real-time multimedia applications require guaranteed
performance communication services, such as throughput,
delay, delay jitter and loss rate.
The characteristics of a source, such as peak and average
rate, are known at channel establishment time.
Channel parameters have to be predicted in live continuous
video sources.
E0262 - Multimedia Communications
Communication Service for Multimedia
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Quality-of-service (QoS) support and group communication system:
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establishment and take-down of appropriately congured channels;
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negotiation of QOS levels between end-systems, intermediate
systems, and network control; and
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control of the agreed QOS level
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bandwidth, delay, delay jitter (variance), and reliability.
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Audio/Video groups can:
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have static or dynamic memberships during their lifetime,
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have centrally (typically sender) or distributedly (typically receiver)
controlled membership,
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consist of members with homogeneous or be heterogeneous
characteristics and requirements.
E0262 - Multimedia Communications
Multimedia Communication System
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Communication system - A system or facility capable of
providing information transfer between persons and
equipment.
CD-ROM: “Compact disk read-only memory.”
Client-Server Model: A client makes a request and a server
fulfills that request.
Composite Video: Analog video signals can be broken
down into parts such as luminance (Black & White) and
chrominance (color).
E0262 - Multimedia Communications
Multimedia File types
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Here are some examples of le types:
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Text Files: .txt, .doc, .rtf
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Audio Files: .au, .aif, .wav
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Graphic files: .jpg, .gif, .tif, .bmp, .pict, .pcx
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Moving video files: .qt, .mov, .avi
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Animation: .fli, .flc
E0262 - Multimedia Communications
Multimedia Communication System
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Interactive Multimedia Design
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Interlacing
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Interleaved
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Linear Multimedia
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Non-Interactive Multimedia
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Nonlinear Multimedia
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Presentation Multimedia
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Latency and Bandwidth
E0262 - Multimedia Communications
Multimedia Application Environment
E0262 - Multimedia Communications
Multimedia Communication System
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LAN Access Method
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Routing
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Frame and Packet Structures
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Packet Discrimination
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Identify packets that require special handling.
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Be capable of accommodating those special requirements.
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Bandwidth Requirement, Reservation and Conservation
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High bandwidth and low latency
E0262 - Multimedia Communications
Multimedia Communication System
Architecture
The ability to manage dynamically the achieved QoS of each service
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component
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The possibility for users to select some resources that best meet their needs.
The possibility to interact with another user whose equipment has differing
characteristics.
The communications network must allow any user to select the service
components he/she wants:
The possibility for users to join in or withdraw from a communication session
according to certain policies, such as agreement of all interacting partners
before admitting a new user.
The possibility to set such quality of service parameters as the synchronization
tolerance between the service components, the echo sensitivity, the burst
sensitivity, and so on.
E0262 - Multimedia Communications
Multimedia Networks
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Technical Issues
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Admission control
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Scheduling
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Resource management
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Congestion control
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Policing/Shaping
E0262 - Multimedia Communications
Multimedia Network Reference Model
E0262 - Multimedia Communications
Multimedia Hardware/Software
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Audio/Video Hardware
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Digital Video (DV)
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Analog to Digital devices
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Built-in Hardware
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Digital Video Software
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Multimedia Software
E0262 - Multimedia Communications
Comparison of Stacks
E0262 - Multimedia Communications
INTERNET
E0262 - Multimedia Communications
Connection to Internet
E0262 - Multimedia Communications
Multimedia Internet Protocols
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Multimedia over TCP
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Multimedia over UDP
E0262 - Multimedia Communications
RTP
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Real-time Transport Protocol (RTP) provides support for the
transport of real-time data such as video and audio streams.
RTP needs support from lower layers that actually have
control over resources in switches and routers
RTP/RTCP provides functionality and control mechanisms
necessary for carrying real-time content.
RTP/RTCP itself is not responsible for the higher-level tasks
like assembly and synchronization. These have to be done
at application level.
E0262 - Multimedia Communications
RTCP
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Real-Time Control Protocol extends RTP
In an RTP session, participants periodically send RTCP packets to convey
feedback on quality of data delivery and information of membership.
Packets defined for carrying control information:
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SR: Sender report, for transmission and reception statistics from session
participants that are
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active senders.
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RR: Receiver report, for reception statistics from session participants, that
are not active
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senders.
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SDES: Source description items, including CNAME
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BYE: Indicates end of participation
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APP: Application specific functions
E0262 - Multimedia Communications
Multimedia Internet Protocols
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SAP & SDP
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SIP
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Peer to peer communication, the concept of session.
Signaling mechanisms that are necessary to establish a
session and to negotiate the parameters to be used in it, such
as codecs, media, location, etc.
MBONE Tools
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SDR, VIC, VAT and RAT, WB, NTE.
E0262 - Multimedia Communications
Multimedia Internet Protocols
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RSVP
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Network control protocol
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Allows data receiver to request a special end-to-end quality of
service for its data flows.
RTSP
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A client-server multimedia presentation protocol to enable
controlled delivery of streamed multimedia data over IP
network.
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Aims to provide the same services on streamed audio and
video just as HTTP does for text and graphics.
E0262 - Multimedia Communications
Multimedia Communications
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High-Density File Transfers
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Graphics File Transfers
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Audio File Transfers
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Video File Transfers
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Audio Communication
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Computer-Based Telephony
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Computer-Based Audio Conferencing
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Streaming Audio
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Video Communication
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Video Conferencing
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Streaming Video
E0262 - Multimedia Communications