Data Communication Networking concepts

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 (Ph. D)

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 (Ph. D)

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

5. Introduction
5
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 (Ph. D)

6. Introduction
6
OSI Reference Model:
The Open Systems Interconnection (OSI) model is a reference tool for understanding
data communications between any two-networked systems.
➢ Application Layer: This layer is responsible for providing interface to the
application user. This layer encompasses protocols which interact with the user.
➢ Presentation Layer: This layer defines how data in the native format of remote host
should be presented in the native format of host.
➢ Session Layer: This layer maintains sessions between remote hosts. For example,
once user authentication is done, the remote host maintains this session for a while
and does not ask for authentication again in that time span.
➢ Transport Layer: This layer is responsible for end-to-end delivery between hosts.
Prof. K. Adisesha (Ph. D)

7. Introduction
7
OSI Reference Model:
The Open Systems Interconnection (OSI) model is a reference tool for understanding
data communications between any two-networked systems.
➢ Network Layer: This layer is responsible for address assignment and uniquely
addressing hosts in a network.
➢ Data Link Layer: This layer is responsible for reading and writing data from and
onto the line. Link errors are detected at this layer.
➢ Physical Layer: This layer defines the hardware, cabling wiring, power output, pulse
rate etc.
Prof. K. Adisesha (Ph. D)

8. Introduction
8
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/Internet Layer
❖ Data Link & Physical Layer
Prof. K. Adisesha (Ph. D)

9. Introduction
9
TCP/IP Model:
Internet uses TCP/IP protocol suite, also known as Internet suite. This defines
Internet Model which contains four layered architecture.
➢ Application Layer: This layer defines the protocol which enables user to interact with
the network. For example, FTP, HTTP etc.
➢ Transport Layer: This layer defines how data should flow between hosts. Major
protocol at this layer is Transmission Control Protocol (TCP).
➢ Internet Layer: Internet Protocol (IP) works on this layer. This layer facilitates host
addressing and recognition. This layer defines routing.
➢ Link Layer: This layer provides mechanism of sending and receiving actual data.
Prof. K. Adisesha (Ph. D)

10. 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 (Ph. D)

11. 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 (Ph. D)

12. 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 (Ph. D)

13. 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 (Ph. D)

14. 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.
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Prof. K. Adisesha (Ph. D)

15. Transmission Modes
Transmission Modes of a Data Communications system:
Communication between two devices can be unidirectional or bi-directional modes.
Data Transmission Modes:
➢ 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.
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Prof. K. Adisesha (Ph. D)

16. Transmission Modes
Transmission Modes of a Data Communications system:
Communication between two devices can be unidirectional or bi-directional modes.
Data Transmission Modes:
➢ 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 (Ph. D)

17. 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 (Ph. D)

18. 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 (Ph. D)

19. 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 (Ph. D)

20. 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 (Ph. D)

21. 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 (Ph. D)

22. 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 (Ph. D)

23. 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 (PAN)
➢ Local Area Network (LAN)
➢ Metropolitan Area Network (MAN)
➢ Wide Area Network (WAN)
Prof. K. Adisesha (Ph. D)

24. 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 (Ph. D)

25. Network Switching
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Classification of Network Switching
Switching is process to forward packets coming in from one port to a port leading
towards the destination.
➢ When data comes on a port it is called ingress, and when data leaves a port or goes out
it is called egress.
➢ At broad level, switching can be divided into two major categories:
❖ Connectionless: The data is forwarded on behalf of forwarding tables. No
previous handshaking is required and acknowledgements are optional.
❖ Connection Oriented: Before switching data to be forwarded to destination, there
is a need to pre-establish circuit along the path between both endpoints. Data is
then forwarded on that circuit.
Prof. K. Adisesha (Ph. D)

26. Network Switching
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Types of Network Switching
A communication system may include number of switches and nodes.
➢ When data comes on a port it is called ingress, and when data leaves a port or goes out
it is called egress.
➢ Switching can be divided into three types:
❖ Circuit Switching
❖ Message Switching
❖ Packet Switching
Prof. K. Adisesha (Ph. D)

27. Network Switching
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Types of Network Switching
A communication system may include number of switches and nodes.
➢ When data comes on a port it is called ingress, and when data leaves a port or goes out
it is called egress.
➢ At broad level, switching can be divided into three types:
❖ Circuit Switching: When two nodes communicate with each other over a
dedicated communication path, it is called circuit switching.
❖ Message Switching: In message switching, the whole message is treated as a data
unit and is switching / transferred in its entirety.
❖ Packet Switching: The entire message is broken down into smaller chunks called
packets. The header is added into each packet and transmitted independently.
Prof. K. Adisesha (Ph. D)

28. Queries
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Prof. K. Adisesha (Ph. D)