The document discusses the architecture and services of multimedia communication networks, highlighting the OSI layers and protocols necessary for efficient data transmission. It emphasizes the importance of quality of service (QoS) and resource management to handle both discrete and continuous media in distributed multimedia systems. Moreover, it outlines the features of these systems, including technology integration, real-time performance, and interactivity, while addressing challenges such as network congestion and dynamic QoS requirements.

1. Presented by: Mohammad Ilyas Malik
M.Tech cse-2nd sem
17320363007
Summited. To:
Er. Khushboo Bansal
(AP of CSE Dept..)

2.  Building communication networks
 OSI layers.
 Multimedia communication over networks
 Distributed multimedia system
 Quality of service
 Resource management

3.  A multimedia networking system allows for the
data exchange of discrete and continuous media
among computers.
 This communication requires proper service and
protocols for data transmission.
 LAYERS: Provide a set of operations to the
requesting application. Logically related services
are grouped into layers according to the OSI layes.
 PROTOCOL: A protocol consists of a set of rules
which must be followed by peer layer instances
during any communication between these two
peers.

4.  The increase in communication of multimedia
information over the past decades has resulted in
many new multimedia processing and
communication systems , being put into service.
 The growing availability of optical fiber links and
rapid progress in VLSI circuits and systems have
fostered a tremendous interest in developing
sophisticated multimedia services with an
acceptable cost.
 Today's fiber technology offers a transmission
capacity that can easily handle high bit rates. This
leads to the development of networks which
integrate all types of Information.

5.  By way of describing multimedia communication
systems, let us consider the individual layers of the
ISO-OSI reference models, which provides at least
the conceptual basis for any communication
system:
1. PHYSICAL LAYER
2. DATA LINK LAYER
3. NETWORK LAYER
4. TRANSPORT LAYER
5. SESSION LAYER
6. PRESENTATION LAYER
7. APPLICATION LAYER

7.  The physical layer defines the transmission method of
individual bits over the physical medium , such as fiber
optics.
 For e.g..: the type of modulation and bit-synchronization
are important issues.
 The delay during the transmission arises due to
propagation speed of the transmission medium and the
electric circuits.
 They determine the maximal possible bandwidth of this
communication channel.
 For audio/video data in general ,the delays must be
minimized and a relatively high bandwidth should
achieved.

8.  It provides the transmission of information blocks
known as data frames.
 To avoid larger delays , the error control for
multimedia transmission needs a different
mechanism that retransmission because a late frame is
a lost frame.
 However because of new high speed networks based
on fiber optics , there may be not any error control at
this layer.
 These networks are favor multimedia transmission
because of their very low transmission rate.

9.  In this layer transport information blocks , called
packets , from one station to another.
 The transport may involves several networks.
 This layer provides services like- addressing,
internetworking, error handling and sequence of
packets.
 Continuous media requires resource reservation
and guarantees for transmission at this layer.
 This is defined through QoS parameters.
 For this purpose connection oriented behavior is

10. Needed where the reservation is made during the
connection setup.
 if internetworking is included , for different
communication structures in multicasting,
broadcasting connections the duplication of
packets can follow , which may introduce
further complexity.
 The network QoS for a connection should be
negotiated at this layer.

11.  This layer provides a process to process
connection.
 In this the QoS which is provided by n/w layer
, is enhanced, Meaning that if the network
service is poor, the transport layer is bridge to
gap b/w what the transport users want and
what the n/w layer provides.
 Large packets are segmented at this layer and
resembled into the original size at the receiver.

12.  Error handling is based on process to process
communication.
 In this the error handling does not include
retransmission because this mechanism high
end-to-end delays and strong jitter.
 The main function of this layer to synchronize
time relations b/w two LDU’s of one
connection and b/w SDU’s of different
connections.

13.  This layer abstracts from different formats and
provide common formats.
 An e.g. of is the different representation of a
number of for Intel or Motorola processors.
 The multitude of audio and video formats also
require conversion b/w formats.
 This problem also comes up outside of the
communication components during exchange
b/w data carriers , such as CD-ROM’s, which
store continuous data .

14.  This layer considers all application –specific services ,
such as file transfer service embedded in the file
transfer protocol(ftp) and the electronic mail service.
 With respect to audio and video ,special services for
support of real time access and transmission must be
provided.
 E.g.. In the case of an application such as , video-on-
demand , special servers on the video server side for
support of real-time db. access and transmission must
be developed.

15.  The main goal of distributed multimedia
communication is to transmit all their media over
the same network.
 A distributed multimedia system (DMS) is an
integrated communication, computing, and
information system that enables the processing,
management, delivery, and presentation of
synchronized multimedia information with
quality-of-service guarantees.
 Multimedia information may include discrete
media data, such as text, data, and images, and
continuous media data, such as video and audio.

16.  Such a system enhances human communications by
exploiting both visual and aural senses and provides
the ultimate flexibility in work and entertainment,
allowing one to collaborate with remote participants,
view movies on demand, access on-line digital libraries
from the desktop, and so forth.
 E.g., Digital media, distributed systems, hypermedia,
interactive TV, multimedia, multimedia
communications, multimedia systems, video
conferencing.

17. • The main features of a DMS are summarized as follows:
1) Technology integration: integrates information,
communication and computing systems to form a unified
digital processing environment.

18.  Multimedia integration: accommodates discrete data as
well as continuous data in an integrated environment
 Real-time performance: requires the storage systems,
processing systems, and transmission systems to
have real-time performance. Hence, huge storage
volume, high I/O rate, high network transmission
rate, and high CPU processing rate are required
 System-wide QoS support: supports diverse QoS
requirements on an end-to-end basis along the data
path from the sender, through the transport network,
and to the receiver.

19.  Interactivity: requires duplex communication
between the user and the system and allows each
user to control the information.
 Multimedia synchronization support: preserves the
playback continuity of media frames within a
single continuous media stream and the temporal
relationships among multiple related data objects.
 Standardization support: allows interoperability
despite heterogeneity in the information content,
presentation format, user interfaces, network
protocols, and consumer electronics.

20.  These are broadly classified into three types:
 ITV, tele-cooperation, and hypermedia.
 Interactive TV: An Interactive TV service is
VOD. VOD provides electronic video-rental
services over the broad-band network .
 Customers are allowed to select programs from
remote massive video archives, view at the
time they wish without leaving the comfort of
their homes, and interact with the programs via
VCR-like functions, such as fast-forward and
rewind.

21.  A VOD system that satisfies all of these requirements (any
video, any time, any VCR-like user interaction) is called a
true VOD system and is said to provide true VOD
services; otherwise, it is called a near VOD system.

22.  Tele cooperation: Tele cooperation, also known as
computer-supported cooperative work (CSCW) or
groupware, refers to a system that provides an
electronic shared workspace to geographically
dispersed users with communication, collaboration,
and coordination supports.
 Group communication provides an electronic channel
for the users to exchange messages either
synchronously or asynchronously.

23. Hypermedia Applications
Hypertext incorporates the notions of navigation, annotation and tailored
presentation to provide a flexible structure and access to computer-based
digital information.
A hypermedia system may be treated as an application of database systems
because it provides flexible access to multimedia information

24.  A hypermedia system allows the user more freedom in
assimilating and exploring information, while the
conventional database system has well-defined
structures and manipulation languages for data
processing.

25.  Quality of service is the ability to provide different
priority to different applications, users, or data
flows, or to guarantee a certain level of
performance to a data flow. For example, a
required bit rate, delay, delay variation, packet loss
or bit error rates may be guaranteed. Quality of
service is important for real-time streaming
multimedia applications such as voice over IP,
multiplayer online games and IPTV, since these
often require fixed bit rate and are delay sensitive.
Quality of service is especially important in
networks where the capacity is a limited resource,
for example in cellular data communication.

26.  A simplified QoS operation model of a multimedia
communication system can be described as follows.
The user’s requirement is specified via an Application
Programming Interface (API). The system then
determines whether it has sufficient resources to meet
the requirements. If so, it will accept the application
and allocate the necessary resources to serve the
application so that its requirements are satisfied. If it
has insufficient resources to meet the application’s
requirement, it may either reject the application or
suggest a lower QoS requirement that it can satisfy to
the application. On the basis of this operation model,
there should be the following components in order to
provide QoS guarantees:

27.  • A QoS specification mechanism for application
to specify their requirements.
 • Admission control to determine whether the
new application should be admitted without
affecting the QoS of the other on going application.
 • A QoS negotiation process so that a system may
support as many application as possible.
 • Resource allocation and scheduling to meet QoS
requirement of accepted applications.
 • Traffic policing to make sure that applications
generate the correct amount of data within agreed
specification.

28.  The QoS model considered here is fairly simple which
tends to get complicated when the QoS requirements
change during an application session. Sometimes the
negotiated parameters cannot be maintained due to
network congestion, requiring renegotiation. Some
parameters are mutually dependent or contradictory,
an example of this is decreasing the error rate by
permitting the retransmission will increase the average
transmission delay. In spite of the contract resulting
from QoS negotiation, the actual QoS values in a
System can vary over the time. Therefore a system
must continuously monitor the actual QoS and employ
correction mechanism like blocking low priority tasks.
In this perspective maintaining QoS becomes a
complex problem.

30.  To achieve an end to end quality of service along
multimedia communications path for distributed
multimedia applications, we need to provide
services and protocols in the end points and
networks which understand what quality of
service is and how to map this quality into the
required resource allocation. Furthermore, the
underlining resource management must have
services and protocols which know how to
negotiate, admit, reserve and enforce requested
resource allocation according to requested QoS
requirements. The resource management ensures
end to-end QoS guarantees. Such guarantees have
the following characteristics:

31.  1. System-wide resources management and
admission control to ensure desired QoS level.
 2. Quantitative specification (packet loss
probability, delay jitter) rather than qualitative
description as in the Internet Transmission Control
Protocol/Internet Protocol (TCP/IP). This gives
the flexibility to accommodate a wide range of
allocations with diverse QoS requirements
 3. Dynamic management. It means that QoS is
dynamically adjusted rather than statistically
maintained though out the lifetime of the
connection.