CCN Unit-1&2 Data Communication &Networking by K. Adiaesha

1. Data Communication
Networking
Prof. K ADISESHA (Ph. D)

2. Data
Communications
& Networking Introduction
Components
Transmission Modes
Networks
Queries
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Characteristics
Contents--
Prof. K. Adisesha

3. Introduction
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Definition:
“Data communications refers to the exchange of data between two devices via some
form of transmission medium such as a wire cable..”
A network can be defined as "A collection of two or more devices which are
interconnected using common protocols to exchange data."
Prof. K. Adisesha

4. Introduction
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Definition:
In general terms, communications can be said to involve three agents:
➢ Applications (file transfer)
➢ Computers (PCs & servers)
➢ Networks.
Prof. K. Adisesha

5. Introduction
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OSI Reference Model:
The Open Systems Interconnection (OSI) model is a reference tool for understanding
data communications between any two-networked systems.
➢ It divides the communications process into
simpler components called seven layers.
➢ The three lowest layers focus on passing
traffic through the network to end system.
➢ The top four layers come into play in the end
system to complete the process
Prof. K. Adisesha

6. Introduction
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TCP/IP Model:
It stands for Transmission Control Protocol/Internet Protocol. The TCP/IP model is a
concise version of the OSI model.
➢ TCP/IP model, it was designed and developed by
Department of Defense (DoD) in 1960s and is based on
standard protocols.
➢ It contains four layers:
❖ Process/Application Layer
❖ Host-to-Host/Transport Layer
❖ Network Layer
❖ Network Access Layer (Data Link & Physical Layer)
Prof. K. Adisesha

7. Characteristics
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The characteristics of a data communications system:
“Data Communications to occur, the communicating devices must be part of a
communication system made up of a combination of hardware and software "
➢ Delivery: The system must deliver data to the correct destination. Data must be
received by the intended device or user and only by that device or user.
➢ Accuracy: The system must deliver the data accurately. Data that have been altered in
transmission and left uncorrected are unusable.
➢ Timeliness: The system must deliver data in a timely manner. Data delivered late are
useless.
➢ Jitter: Jitter refers to the variation in the packet arrival time. It is the uneven delay in
the delivery of audio or video packets.
Prof. K. Adisesha

8. Components
Components of a data communications system:
A data communications system has five components:
➢ Message
➢ Sender
➢ Receiver
➢ Transmission medium
➢ Protocol
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Prof. K. Adisesha

9. Components
Components of a Data Communications system:
A data communications system has five components:
➢ Message: The message is the information (data) to be communicated. Popular forms of
information include text, numbers, pictures, audio, and video.
➢ Sender: The sender is the device that sends the data message. It can be a computer, workstation,
telephone handset, video camera, and so on.
➢ Receiver: The receiver is the device that receives the message. It can be a computer,
workstation, telephone handset, television, and so on.
➢ Transmission medium: The transmission medium is the physical path by which a message
travels from sender to receiver.
➢ Protocol: A protocol is a set of rules that govern data communications. It represents an
agreement between the communicating devices.
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Prof. K. Adisesha

10. Transmission Modes
Transmission Modes of a Data Communications system:
Communication between two devices can be unidirectional or bi-directional modes.
Data Transmission Modes:
➢ Simplex Mode
➢ Half-duplex Mode
➢ Full-duplex Mode
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Prof. K. Adisesha

11. Transmission Modes
Transmission Modes of a Data Communications system:
Communication between two devices can be unidirectional or bi-directional modes.
Data Transmission Modes:
➢ Simplex : In simplex mode, the communication is unidirectional, as on a one-way street.
Only one of the two devices on a link can transmit; the other can only receive.
➢ Half-duplex : In half-duplex mode, each station can both transmit and receive, but not
at the same time. When one device is sending, the other can only receive, and vice versa.
➢ Full-duplex :In full-duplex mode, both stations can transmit and receive simultaneously.
The full-duplex mode is like a two way street with traffic flowing in both directions at the
same time.
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Prof. K. Adisesha

12. Transmission Medium
Transmission Medium in a Data Communications system:
In data communication terminology, a transmission medium is a physical path between
the transmitter and the receiver through which data is sent from one place to another.
The factors to be considered are:
➢ Transmission rate
➢ Distance
➢ Cost
➢ Easy of installation
➢ Resistance to environmental condition.
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Prof. K. Adisesha

13. Transmission Medium
Transmission Medium in a Data Communications system:
There are two type of transmission media:
➢ Guided media are:
❖ Twisted Pair: Unshielded Twisted Pair (UTP), Shielded Twisted pair (STP)
❖ Co-axial cable: Thinnet, Thicknet
❖ Optical Fiber cable
➢ Unguided media are:
❖ Radio wave Transmission
❖ Microwave Transmission
❖ Satellite Communication
❖ Infrared
❖ Laser
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Prof. K. Adisesha

14. Transmission Medium
Transmission Medium in a Data Communications system:
Guided transmission media: It is also referred to as Wired or Bounded transmission
media. Signals being transmitted are directed and confined in a narrow pathway by
using physical links.
➢ Guided media are:
❖ Twisted Pair: Unshielded Twisted Pair (UTP), Shielded Twisted pair (STP)
❖ Co-axial cable: Thinnet, Thicknet
❖ Optical Fiber cable
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Prof. K. Adisesha

15. Transmission Medium
Transmission Medium in a Data Communications system:
Unguided transmission media: It is also referred to as Wireless or Unbounded
transmission media. No physical medium is required for the transmission of
electromagnetic signals.
➢ Unguided media are:
❖ Radio wave Transmission
❖ Microwave Transmission
❖ Satellite Communication
❖ Infrared
❖ Laser
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Prof. K. Adisesha

16. Network
Network in Data Communications system:
A network is a set of devices (often referred to as nodes) connected by communication
links. A node can be a computer, printer, or any other device capable of sending and/or
receiving data generated by other nodes on the network.
Type of Connection:
➢ Point-to-Point
➢ Multi-point
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Prof. K. Adisesha

17. Network
Network in Data Communications system:
A network is a set of devices (often referred to as nodes) connected by communication
links. A node can be a computer, printer, or any other device capable of sending and/or
receiving data generated by other nodes on the network.
Type of Connection:
➢ Point-to-Point : A point-to-point connection provides a dedicated link between two
devices. The entire capacity of the link is reserved for transmission between those two
devices.
➢ Multipoint : A multipoint connection is one in which more than two specific devices
share a single link. In a multipoint environment, the capacity of the channel is shared,
either spatially or temporally.
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Prof. K. Adisesha

18. Classification of Networks
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Types of Network
A computer network means a group of networked components, i.e., computers are linked
by means of a communication system.
There are three types of network.
➢ Personal Area Network (LAN)
➢ Local Area Network (LAN)
➢ Wide Area Network (WAN)
➢ Metropolitan Area Network (MAN)
Prof. K. Adisesha

19. Network Topologies
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Classification of Network Topologies
Network Topology refers to the arrangement of computers and other devices in a network.
➢ Need for Topologies are: Cost, Flexibility, and Reliability.
➢ Network topologies can be classified as follows:
❖ Bus Topology
❖ Star Topology
❖ Ring Topology
❖ Mesh Topology
❖ Hybrid Topology
Prof. K. Adisesha

20. Network Topologies
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Switching techniques
In large networks, there can be multiple paths from sender to receiver. The switching
technique will decide the best route for data transmission.
➢ Switching technique is used to connect the systems for making one-to-one communication.
➢ Classification of Switching Techniques.
Prof. K. Adisesha
❖ Circuit switching: is a switching technique that establishes a
dedicated path between sender and receiver.
❖ Message Switching: is a switching technique in which a message
is transferred as a complete unit and routed through
intermediate nodes at which it is stored and forwarded.
❖ Packet switching: is a switching technique in which the message
is sent in one go, but it is divided into smaller pieces, and they
are sent individually.

21. Network Topologies
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Multiplexing
Multiplexing is the process of combining multiple signals into one signal, over a shared
medium.
➢ The process of multiplexing divides a communication channel into several number of logical
channels
➢ If analog signals are multiplexed, it is Analog Multiplexing and if digital signals are
multiplexed, that process is Digital Multiplexing.
➢ There are Five types of Multiplexing :
❖ Frequency Division Multiplexing (FDM)
❖ Time-Division Multiplexing (TDM)
❖ Wavelength Division Multiplexing (WDM)
❖ Code-division multiplexing (CDM)
❖ Space-division multiplexing (SDM):
Prof. K. Adisesha

22. Queries
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Prof. K. Adisesha