Components of Data Communication Systems, Modes of Data Communications, Applications of Networks, Physical Topologies and their types, Categories of Networks: LAN, MAN, WAN

1. DATA COMMUNICATION &
NETWORKS

2. Data Communication
Exchange of data between two or more
devices using some transmission
medium.
Another explanation could be:
Electronic transmission of information
that has been encoded digitally (as for
storage and processing by computers)

3. Components of Data
Communication System
 Message (text, image, numbers, audio, video)
 Sender(computer, workstation, telephone,
camera etc.)
 Receiver
 Transmission Medium(twisted-pair, optical
fiber, coaxial cable, radio waves)
 Protocol(set of rules that govern data
communication)

4. Mode of Data
Communications
 Simplex (unidirectional)
 Half-Duplex (bidirectional)
 Full-Duplex(bidirectional)

5. Applications of Networks
 Resource Sharing
 Hardware (Computing Resources, Disks, Printers, etc.)
 Software (Application Software)
 Information Sharing
 Easy accessibility from anywhere (Files, Databases, etc.)
 Search Capability (WWW)
 Communication
 Email
 Message Broadcasting

6. Network Criteria
 Performance:
Transmit Time, Response Time,
Throughput
 Reliability:
Frequency of failure, Time to recover
 Security:
Unauthorized Access, Protecting Data

7. Physical Topology
 It refers to the way how the network is
laid out physically.
 Geometric representation of the
relationship of all the links and linking
devices

8. Types of Physical Topologies
 Mesh Topology
 Star Topology
 Bus Topology
 Ring Topology
 Hybrid Topology

9. Mesh Topology

10. Star Topology

11. Bus Topology

12. Ring Topology

13. Hybrid Topology

14. Categories of Networks
 Local Area Network (LAN)
 Wide Area Network (WAN)
 Metropolitan Area Network (MAN)

15. Local Area Network
 Privately owned computer network that
connects computers and other information
processing device.
 LAN size – Few Kilometers
 LAN Examples
 Ethernet (CSMA/CD)
 LocalTalk (CSMA/CA)
 Wireless LAN
 Token Ring

16. LAN

17. Wide Area Network
Network that covers a broad area
 Example- Any telecommunications
network that links across
metropolitan, regional, or national
boundaries.

18. WAN

19. Metropolitan Area
Network(MAN)
 Designed to extend over the entire city.
 It may be a single network as a cable TV
network OR
 It may be means of connecting a number of
LANs into a larger network
 The main reason for distinguishing MANs as a
special category is that a standard has been
adopted for them. It is DQDB(Distributed
Queue Dual Bus) or IEEE 802.6.

21. Protocols and Standards
Protocol:
 Syntax
The structure or format of data, i.e. the order
in which they are presented.
 Semantics
Semantics refers to the meaning of each
section of bits.
 Timing
When and how fast data to be sent.

22. Standards:
 De facto Standards -
Not approved by an organized
body.
 De jure Standards -
Approved by an organized body.