ESSENTIAL of (CS/IT/IS) class 07 (Networks)

Class 07, Database, ESSENTIAL of (CS/IT/IS), for 1st level students of College of Computers, ESSENTIAL of (CS/IT/IS) class 07 (Networks)

1. ESSENTIAL of (CS/IT/IS) Instructor: Dr. Mazin Md. Alkathiri Information technology Department Faculty of Applied Sciences Seiyun University – Yemen Jan 2024

2. Lecture 6 : Networking and data communication 2

3. The term telecommunication means communication at a distance. The word data refers to information presented in whatever form is agreed upon by the parties creating and using the data. Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable. DATA COMMUNICATIONS 3

4. 1. 4 Figure 1.1 Components of a data communication system

5. 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. A link can be a cable, air, optical fiber, or any medium which can transport a signal carrying information. NETWORKS 5

6. Computer systems and peripherals are connected to form a network. They provide numerous advantages: Resource sharing such as printers and storage devices Exchange of information by means of e-Mails and FTP Information sharing by using Web or Internet Interaction with other users using dynamic web pages IP phones Video conferences Parallel computing Instant messaging Applications 6

7. 1. 7 Network Criteria Performance Depends on Network Elements Measured in terms of Delay and Throughput Reliability Failure rate of network components Measured in terms of availability/robustness Security Data protection against corruption/loss of data due to: Errors Malicious users

8. Type of Connection Point to Point - single transmitter and receiver Multipoint - multiple recipients of single transmission Physical Topology Connection of devices Type of transmission - unicast, mulitcast , broadcast 1. 8 Physical Structures

9. is a unicast connection. There is a dedicated link between an individual pair of sender and receiver. The capacity of the entire channel is reserved only for the transmission of the packet between the sender and receiver. Types of connections:(A) point-to-point 9

10. also called multidrop line configuration. a single link is shared by multiple devices. the channel capacity is shared temporarily by every device connecting to the link. Types of connections: (B) Multipoint 10

11. A Network Topology is the arrangement with which computer systems or network devices are connected to each other. Topologies may define both physical and logical aspect of the network. Categories of topology 1. 11

12. In this type of topology, a host is connected to one or multiple hosts. This topology has hosts in point-to-point connection with every other host or may also have hosts which are in point-to-point connection with few hosts only. A fully connected mesh topology (five devices) 1. 12

13. All hosts in Star topology are connected to a central device, known as hub device, using a point-to-point connection. That is, there exists a point to point connection between hosts and hub. A star topology connecting four stations 1. 13

14. In case of Bus topology, all devices share single communication line or cable. Bus topology may have problem while multiple hosts sending data at the same time. A bus topology connecting three stations 1. 14

15. In ring topology, each host machine connects to exactly two other machines, creating a circular network structure. When one host tries to communicate or send message to a host which is not adjacent to it, the data travels through all intermediate hosts A ring topology connecting six stations 1. 15

16. A network structure whose design contains more than one topology is said to be hybrid topology. A hybrid topology: a star backbone with three bus networks 1. 16

17. 1. 17 Categories of Networks Personal Area Network (PANs) Local Area Networks (LANs) Metropolitan Area Networks (MANs) Wide Area Networks (WANs)

18. A Personal Area Network (PAN) is smallest network which is very personal to a user. This may include Bluetooth enabled devices or infra-red enabled devices. PAN has connectivity range up to 10 meters. PAN may include wireless computer keyboard and mouse, Bluetooth enabled headphones, wireless printers and TV remotes. Personal Area Network 1. 18

19. A computer network spanned inside a building and operated under single administrative system is generally termed as Local Area Network (LAN). Usually, LAN covers an organization’ offices, schools, colleges or universities. Number of systems connected in LAN may vary from as least as two to as much as 16 million. LAN provides a useful way of sharing the resources between end users. The resources such as printers, file servers, scanners, and internet are easily sharable among computers. LAN can be wired, wireless, or in both forms at once. Local Area Network 19

20. LAN 20

21. The Metropolitan Area Network (MAN) generally expands throughout a city such as cable TV network. Metro Ethernet is a service which is provided by ISPs. This service enables its users to expand their Local Area Networks. For example, MAN can help an organization to connect all of its offices in a city. Backbone of MAN is high-capacity and high-speed fiber optics.  Metropolitan Area Network 21

22. MAN 22

23. As the name suggests, the Wide Area Network (WAN) covers a wide area which may span across provinces and even a whole country. Generally, telecommunication networks are Wide Area Network. These networks provide connectivity to MANs and LANs. Since they are equipped with very high speed backbone, WANs use very expensive network equipment. Wide Area Network 23

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