DATA COMMUNICATION AND NETWORKING
5. NETWORKING FUNDAMENTALS (Part-1)
An overview of networking
Switching techniques: -
a. Circuit Switching
b. Packet Switching
c. Message Switching
Network Topologies: -
a. Bus Topologies
b. Ring Topologies
c. Star Topologies
Introduction to networking fundamentals and an overview of networking: -
1. A network is set up by connecting two or more computers and other supporting hardware i.e. printers, disk drivers, etc. devices through communication channels is called a computer network.
2. A system in which multiple computers are connected to each other to share information and resources is also known as computer network.
3. When data comes on a port is called ingress and when data leaves a port or goes out is called egress.
4. Characteristics of a computer network are as follows: -
a. To share resources and information from one computer to another.
b. Computer network allows you to share resources such as printer, scanner etc.
c. Created files data are stored in a computer we can access those files from another computer that are connected over the network.
d. By using computer network we can share expensive software and database among network users.
e. Computer network allows the exchanging of data and information among users through a network.
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Some lists of hardware's data required to set up a computer network: -
1. Network cables-
Network Cables are used to connect computers and the most commonly used cable is category 5 cables is RJ-45.
2. Distributors-
a. A central body through which computers, printers, and scanners etc. can be connected and manage to distribute network traffic this Central body is known as distributors.
3. Router-
a. Router is equipped with holes and ports through which computers and other devices are connected using network cable.
b. Now-a-days router comes in wireless module using which computers can be connected without any physical cable.
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1. Network card
a. It is a necessary component of a computer because it helps to connect computers over a network.
b. Network Card are of two types- Internal and External
Internal network cards-
a. There is a slot in motherboard for internal network card where it is to be inserted.
b. Network cables are required to provide network access.
c. Peripheral component interconnect and industry standard architecture.
External Network Cards-
a. It can be of two type wireless and USB based
b. Wireless network card needs to be inserted into the motherboard whereas USB card is easy to use and connect via USB port
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Switching techniques: -
1. There are multiple paths in any large networks from sender to receiver; the switching technique decided the best route for data transmission.
2. It is used to connect the systems for making one to one communication.
3. Selection of a path that master take out of the available option in paths is called switching.
4. A switched network is made up of a series of interconnected nodes called switches.
5. there are basically Three Types of switching techniques
a. Circuit switching
b. Packet switching
c. Message switching
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Circuit Switching: -
1. Circuit switching is the simplest method of data communication in which a dedicated physical communication or path is established between the sending and receiving device.
2. In circuit switching network is set of switches are connected by physical link.
3. Circuits which are take place in the physical layer.
4. In circuit switching a complete end-to-end path must exist before the communication takes place.
5. Circuit switching is used for public Telephone Network for voice transmission.
6. Once the connection is established in circuit switching technique then the dedicated path will remain to exist until the connection is terminated.
7. There are three phases of communication in circuit switching: -a. Circuit establishment
b. Data transfer
c. Circuit disconnect
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Advantage of Circuit Switching Technique: -
1. In circuit switching technique the communication channel is dedicated.
2. Circuit switching has fixed bandwidth.
3. Communication channel is end to end dedicated.
Disadvantages of Circuit Switching Technique: -
1. The only delay occurs in the speed of data transmission once the dedicated path is established.
2. Circuit switching technique takes a long time to establish a connection approx 3 seconds during which no data can be transmitted.
3. It is more expensive than any other switching techniques because it required a dedicated path would each connection.
4. Due to the dedicated path connection no other data can be transferred even if the channel is free.
Message Switching Technique: -
1. Message switching is a logical unit of Information and can be of any length.
2. Message switching does not establish a dedicated path between the two communicating device.
3. In message switching no direct link is established between the sender and the receiver.
4. A dynamic routing is provided by message switching as the message is going through the intermediate nodes based on the information available in the message, and the destination address is enclosed in the message.
5. Switching technique in which a message is transferred as a complete unit and went through intermediate notes at which messages stored and forwarded is known as message switching.
6. They are programmed in such a way so that they can provide most efficient route.
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Advantages of Message Switching Technique are: -
1. In message switching technique data channels are shared among the communicating devices which improve the efficiency of using available bandwidth
2. To manage the network message priority is used.
3. It supports the data of unlimited size because the size of message which is sent over the network can be varied
4. The message is temporarily stored in the nodes which reduced the congestion in traffic.
Disadvantages of Message Switching Technique are: -
1. To store many messages of unlimited sizes each intermediate switching note requires large storage capacity
2. Storing and forwarding methods introduces delay at each switching node which is a suitable for real time applications.
Packet Switching Technique: -
1. Packet switching is a switching technique in which the message is sent in once but it is divided into smaller pieces and they are sent individually.
2. The packet contain data and various control information
3. In packet switching network there is a strict upper bound limit of the size of packets.
4. The splitting of message into smaller pieces known as packets and these packets are given a unique number to identify their order at the receiving end.
5. Smaller pieces of message that is packets are are travel across the network taking the shortest path as possible.
6. All the packets are collected at the receiving end and reassembled in correct order.
7. In the case any packet is missing or corrupted then the message will be send to resend the message.
8. The correct order of the packets is reached then the acknowledgement message will be sent by the receiving end to the sender end.
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Advantages of Packet Switching Technique are: -
1. In packet switching technique packets are sent as soon as they are available which causes fast delivery of packets.
2. Packet switching does not required massive storage because they don't have to store the entire messages before forwarding them to the next node.
3. Packet switching technique allows simultaneous uses of same channel by multiple users.
4. In packet switching technique if any node is busy then the packets can be routed which ensures that this technique provides reliable communication.
5. Packet switching technique is an efficient technique because it does not require any established path to the transmission and many users can use the same communication channel simultaneously.
Disadvantages of Packet Switching Technique are: -
1. Packet switching techniques are unsuitable for applications that can not a fault delays in communication like high quality voice calls.
2. Packet switching required Complex protocols food delivery.
3. The protocol data used in packet switching technique are very complex and requires high implementation cost.
4. It requires re-transmission of Lost packet if the network is overloaded or corrupted which lead to the loss of critical information if errors are not recovered
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