2. Computer Networks & Topologies

3. Group Members Shahid Ahmed Sp11-Bba-100 Shahzad Zeb Sp11-Bba-084 Nadia Naseer Abbasi Sp11-Bba-079 Ahsan Bashir Sp11-Bba-007 Nosherwan Zafar Sp11-Bba-080 Muhammad Fahad Sp11-Bba-082

4. Computer Network A way of connecting computers together so that they can communicate, share information and other resources with each other is called computer network. A computer network is also called the information network.

5. Types of Computer Networks  LAN  WAN  MAN

6. LAN

7. LAN stands for Local Area Network It is used to cover a small area The network of computers in a computer lab of a college and network of computers in an office building are examples of LAN In a LAN, the nodes are connected via cables A LAN may use star topology, ring topology or bus topology A LAN covers small distance such as one office or building

8. WAN

9. WAN stands for wide area network It is used to cover a large or vide area The computers connected to WAN can be in different cities or countries Nodes are connected through telephone lines however they can be connected through microwave or satellite systems Typically a WAN consists of two or more LANs connected together The internet is world’s largest WAN

10. MAN

11. MAN stands for metropolitan area network It covers area of a single city Usually MAN connects more than one LANs in a city or town It covers smaller geographical area than WAN Fibre optic cables are used as communication media So it is very high-speed network Mobile phones (cellular) system often use MAN

12. Network Topology There are many ways in which computers can be connected together in computer network. The way in which computers or other devices are connected in network is called network topology.

13. Types of network Topology  Bus topology  Star topology  Ring topology  Tree topology  Mesh topology

14. Bus topology

15. All nodes or devices are connected to a common communication medium or central single cable that is backbone cable This cable is called Bus It is very simple network and less expensive But it supports only a small number of nodes It does not need much cabling to connect nodes as compared to other networks

16. Star topology

17. Each node is directly connected to a central connection point known as Hub nodes are connected to the Hub with unshielded twisted pair Ethernet Star topology is most commonly used in LAN Many home networks uses the Star topology This network forms a shape like star It is easy to install and to maintain It requires more cabling than Bus topology

18. Ring topology

19. In a ring topology, each node is connected to two adjacent nodes or neighbours It forms a closed ring or loop In this way the last node connects to the first node to complete the ring All the messages travel through a ring in one direction (clockwise or anti-clockwise) Token passing method is used in this topology It is less expensive than star topology

20. Tree topology

21. Nodes are connected to each other in such a way that it forms a tree like structure Multiple star topologies are used to form a tree network It has combined features of bus and star topology One central hub and multiple secondary hubs are used The cable TV network is an example of tree network Main cable is divided into branches and each branch is further divided in to smallest branches and so on

22. Mesh topology

23. Each node is directly connected to every other node on the network This type of network involves concept of routes Some WANs like internet uses Mesh topology Each node can send message to its destination through multiple paths Its performance is not affected with heavy load of data transmission It is difficult to install and is much expensive