Download 4 Distributed Multimedia Systems (PPT Slides) File

Multimedia Communication Systems
Techniques, Standards, and Networks
Chapter 4
Distributed Multimedia Systems
Definitions

DMS – Distributed Multimedia Systems


An integrated communication, computing and
information system that enables the processing,
management, delivery, and presentation of
synchronized multimedia information that the
quality of service guarantees.
Authoring tool

Specialized software which enables the design &
assembly of multimedia elements for a multimedia
presentation
Distributed Multimedia Applications

Interactive television


Telecooperation


Video on demand, home shopping, video games
Distance learning, telecommuting,
videoconferencing
Hypermedia

Linked documents, digital library, on-line
encyclopedia, ezines, information kiosks
DMS Features

Technology Integration

Communication & computing
Multimedia integration
 Real-time
 QoS
 Interactivity
 Synchronization



Of various media streams
Support

Standardization & interoperability
QoS
Applications dependent
 Quantified



Packet loss, delay, jitter
Negotiated between users & service providers

Three levels of delivery




Deterministic
Statistical
Best Effort Delivery
Requires


Resource management
Reservation
Network Variations

Media


Coax, fiber, wireless, satellite
Transport/switching/routing protocols
Connection oriented or connectionless
 Ethernet, ATM, IP
 Unicast, multicast


Network Size

LAN, MAN, WAN
IP Networking
Datagram
 Connectionless
 Best effort



Reliability is left to the end user
Present Internet

Primitive service model



Best effort, point to point
UDP – User (Unreliable) Datagram Protocol
More RTPs (Real-time Transport Protocol) needed

VoIP, multicasting, VoD, etc.
IP Multicast
A single packet to multiple destinations
 Requires a multicast address

Network forwards a copy to each group of
hosts
 Allow users to join & leave the session


Routing protocol categories
Link state (router subsets)
 Distance Vector (destination)

RSVP
Resource Reservation Protocol
 Receiver initiated


PATH message



Flow specification, destination
Receiver determines QoS & initiates RESV
Reservation styles



Fixed filter (video conferencing)
Wildcard filter (audio conferencing)
Shared explicit (sender selection)
RTP

Real-time Transport Protocol
Does not provide QoS
 Provides packet sequence number
 Used for multiparty conferencing



Provides synchronization, framing, & encryption
Used with RTCP

Exchanges QoS & failure information
Integrated Management Architecture

MPLS



Edge-label switches (connect to customers)
Core switches
FCAPS

Integrated management of networks





Performance
Fault
Configuration
Security
Billing
ATM
ATM Forum now MFA Forum
 Connection oriented
 Small cells
 Virtual circuit, virtual path
 QoS



Sustainable rate, peak rate, burst length,
cell loss ratio, delay, jitter
5 Adaptation layers
IP/ATM Integration

IP




Large installation base
Connectionless
Best effort
ATM




QoS
Bandwidth
Connection oriented
Adaptation layers (class of service)
IP/ATM Integration

Switching




IP switching
Tag switching (MPLS)
Cut-through switching
RMOA
 Real-time multimedia over ATM
 Underdevelopment
Distributed Media Servers

Applications


VoD, digital library, in-house training
Complexity
I/O bandwidth
 Information storage/access
 QoS to multiple users
 VCR-like controls

Multimedia Operating Systems

CPU Management



Memory Management


Speed & fragmentation
IO Management


EDF – earliest deadline first
Rate-monitoring scheduling (fixed priority)
Interrupts & transfer rates
File System Management

Real-time & continuous media streams
Interactive Television



Point-to-point switched connections
Asymmetrical bandwidth
Broadcast media



Stored media




streaming
VoD – real-time
file transfer or streaming
VoD – on-line movie rental/video library
video jukebox
SONET/ATM

National distribution
Telecooperation
Telecommuting +
 Electronic shared workspace


Shared applications/documents




Replicated
Concurrent
Cooperation control
Conferencing



Requires multicast
Real-time
Add drop control
Hypermedia

Media Limitations
Proprietary storage mechanisms
 Disparate document formats


The Web
HTTP, URL
 HTML, XHTML, DMTL
 CGI – Common Gateway Interface
 JAVA
