Introductory concepts of data communication lecture-1

Introductory Concepts of Data Communication

1. Lecture-1 Introductory Concepts of Data Communication

2. Basic Communication Model A Communication model is used to exchange data between two parties. For example: communication between a computer, server and telephone. Source Data to be transmitted is generated by this device, example: telephones, personal computers etc.

3. Basic Communication Model Transmitter The data generated by the source system is not directly transmitted in the form its generated. The transmitter transforms and encodes the data in such a form to produce electromagnetic waves or signals . Transmission System A transmission system can be a single transmission line or a complex network connecting source and destination . Receiver Receiver accepts the signal from the transmission system and converts it into a form which is easily managed by the destination device . Destination Destination receives the incoming data from the receiver

4. C omponents of Data Communication Message :  It is the information to be delivered. Sender:  Sender is the person who is sending the message. Receiver:  Receiver is the person to whom the message is being sent to. Medium:  It is the medium through which the message is sent. For example: A Modem. Protocol:  These are some set of rules which govern data communication.

5. What is a Computer Network? Computer network is the interconnection of networks devices(computers, printers, and network hardware) through some medium(wireless or Wired). These connected devices able to exchange data with each other in efficient and consistence way.

6. Components Of Computer Network/Network Hardware

7. Network Interface Card NIC is a device that helps the computer to communicate with another device. The network interface card contains the hardware addresses, the data-link layer protocol use this address to identify the system on the network so that it transfers the data to the correct destination . NIC performs some activates such as sending and receiving data as well as controlling data flow between linked all terminals over the network. NIC is capable to send and receive data on (10,100 to 1000 Mb/s) transfer rate. All NIC contain unique id (MAC address) that is programmed on chip, and it is embedded on the network interface card. There are two types of NIC : Wireless NIC:  All the modern laptops use the wireless NIC. In Wireless NIC, a connection is made using the antenna that employs the  radio wave technology . Wired NIC:  Cables use the  wired NIC  to transfer the data over the medium.

8. Hub Hub  is also a hardware component of  computer network  that helps to split large network connections into small multiple network terminals. Hub works as distribution point. When computes try to request for some piece of data from network (wired or wireless), then it has first priority to send request to Hub via cable. Hub will transmit those requests over the network, and all linked terminal will determine that those requests are related to them or not. If not related then all requests will be trashed.

9. Modem Modem  stands for “ Modulator–Demodulator “. Main objective of using of Modem in  computer network  is to move data from one computer terminal to another computer terminal via telephone line system. Types of modem are : Ethernet modem  – It is connected into NIC in the computer system. Wireless modem  – Wireless modem contains small antenna, and it is connected with computer terminal through wireless network.

10. Switch Switch is a networking device that groups all the devices over the network to transfer the data to another device. A switch is better than Hub as it does not broadcast the message over the network, i.e., it sends the message to the device for which it belongs to. Therefore, we can say that switch sends the message directly from source to the destination.

11. Bridges A bridge is a network device that connects multiple LANs (local area networks) together to form a larger LAN. The process of aggregating networks is called network bridging. A bridge connects the different components so that they appear as parts of a single network. Bridges operate at the data link layer of the OSI model and hence also referred as Layer 2 switches.

12. Router A   router  is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions on the Internet. Data sent through the internet, such as a web page or email, is in the form of data packets. A packet is typically forwarded from one router to another router through the networks that constitute an internetwork (e.g. the Internet) until it reaches its destination node .

13. Gateway A gateway is  a network node that forms a passage between two networks operating with different transmission protocols . 

14. Repeater Repeater  performs all activates on the  physical layer of the OSI model . It is very helpful to regain or replicate analog or digital signals, which are distorted by transmission loss. So it is known as “Signal Booster”.

15. Network Software Network software is defined as a wide range of software that streamlines the operations, design, monitoring, and implementation of computer networks.

16. Functions of network software User management  allows administrators to add or remove users from the network. This is particularly useful when hiring or relieving File management  lets administrators decide the location of data storage and control user access to that data. Access  enables users to enjoy uninterrupted access to network resources. Network security systems  assist administrators in looking after security and preventing data breaches.