Data communication and networks by B. Forouzan
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This document discusses different types of computer network topologies and categories. It describes mesh, star, bus, and ring topologies, providing their key characteristics, advantages, and disadvantages. It also defines local area networks (LANs), wide area networks (WANs), and metropolitan area networks (MANs), and discusses how multiple networks can be interconnected through an internet. The document serves to provide an overview of fundamental network topology and category concepts.
Data communication and networks by B. Forouzan
- 2. Different Types of Networks and Topologies By, T G Preethi , 19ifte073
- 3. Network Topology : â Topology refers to the way in which the network of computers is connected. â Topology can also be defined as the geometrically interconnection pattern by which the stations (nodes/computers) are connected using suitable transmission media (which can be point-to-point and broadcast)
- 4. Types of network topology : â Mesh topology â Star topology â Bus topology â Ring topology
- 5. Mesh topology â In mesh topology, each node is directly connected to every other node on the network. This type of network involves the concept of routes. Mesh topology is rarely used in LAN. Some WANs like the Internet use mesh topology. â In mesh topology, each node can send message to the destination through multiple paths. It means that each node of mesh network has several possible paths to send or to receive message.
- 6. Advantages â It has multiple links, so if one route is blocked then other routes can be used for data communication. â It ensures the data privacy or security, because every message travels along a dedicated link. â Troubleshooting of this topology is easy as compared with other networks. â It performance is not affected with heavy load of data transmission.
- 7. Disadvantages : â It becomes very expensive because a large number of cabling and I/O ports are required. â It is difficult to install.
- 8. Star Topology : â In a star network, all computers or nodes are directly connected to a central device. â The the nodes are connected to the Hub with unshielded twisted pair central device is called Hub. â Star topology is most commonly used in LAN. This form of network shape looks like a Star. â In Star topology, the computers communicate with each other through central Hub. â The sending computer sends data to the Hub. The Hub sends data to the receiving computer. In this way, data is transferred from one computer to another.
- 9. Advantages : â It is easy to install and to maintain. â New nodes can easily be added and removed to and from the central Hub without affecting the network. â If any node or cable fails, other nodes are not affected
- 10. Disadvantages : â It requires more cable than any other topologies. â So it becomes more costly. â This type of network depends upon the central Hub. â If Hub fails, the entire network breaks down.
- 11. Bus topology : â In Bus topology, all nodes (or devices) are connected to a common communication medium. â Usually, a central cable is used as communication medium. This cable is called Bus. The computers or nodes are connected to the Bus through interface connector. In bus network, each computer is assigned a unique address. â When a computer sends a message to another computer, it also attaches the address of the destination computer with message. â This message moves from one computer to other through the bus. Each computer connected to the network checks the message. â If the address matches with the address of computer, then it accepts the message. â Otherwise, the message moves to the next computer. In this way, the message is received by the destination computer.
- 13. Advantages : â It is very simple and easy to install. â It requires small length of cable to connect computers. â It is less expensive. â When a node is added and removed to and from the network, the network is not affected. â If one node fails, other nodes are not affected.
- 14. Disadvantages : â It can support only a small number of nodes or computers. â As the number of computers increases, the network get slower. â Entire network fails if there is any problem in the central cable.
- 15. Ring Topology : â In ring topology, each computer is connected to the next computer and the last computer is connected to the first. â Thus, a ring of computers is formed. â When a computer sends a message to another computer on the network, the message flows from one computer to the next computer. â Every computer receives message from previous computer and transmits it to the next computer until the destination computer receives the message.
- 16. Ring Topology :
- 17. Advantages : â Data is quickly transferred without a bottle neck â The transmission of data is relatively simple as packets travel in one direction only. â Adding additional nodes has very little impact on bandwidth â It prevents network collisions because of the media access method or architecture required.
- 18. Disadvantages : â Data packets must pass through every computer between the sender and recipient therefore this makes it slower. â If any of the nodes fail then the ring is broken and data cannot be transmitted successfully. â It is difficult to troubleshoot the ring. Because all stations are wired together, to add a station you must shut down the network temporarily. â In order for all computers to communicate with each other, all computers must be turned on. Total dependence upon the one cable
- 19. Categories of Networks â Network Category depends on its size â Two primary categories LAN: Covers area < 2 miles WAN: Can be worldwide MAN: Between LAN & WAN, span 10s of miles
- 20. Local Area Network (LAN) â Privately owned â Links devices in the same office, building, or campus â Simple LAN: 2 PCs & 1 printer in home or office â Size is limited to a few kilometers â Allow resources to be shared (hardware, software, or data)
- 21. Local Area Network (LAN)
- 22. Local Area Network (LAN) â LAN is distinguished by: Size (# users of OS, or licensing restrictions) Transmission medium (only one type) Topology (bus, ring, star) â Data Rates (speed): Early: 4 to 16 Mbps Today: 100 to 1000 Mbps
- 23. Wide Area Networks (WAN) â It Provides long-distance transmission of data over large geographic areas (country, continent, world) âSwitched WAN Backbone of the Internet âDial up line point-to-point WAN Leased line from a telephone company
- 24. Wide Area Networks (WAN)
- 26. Metropolitan Area Networks (MAN) â Size between LAN and WAN â Inside a town or a city â Example: The part of the telephone company network that can provide a high-speed DSL to the customer
- 27. Interconnection of Networks: Internetworks Two or more networks connected together The Internet â Internet has revolutionized many aspects of our daily lives. â It has affected the way we do business as well as the way we spend our leisure time.
- 28. Internetworks
- 29. â Internet is a communication system that has brought a wealth of information to our fingertips and organized it for our use â An internet is 2 or more networks that can communicate with each other â The Internet is a collaboration of more than hundreds of thousands of interconnected networks
- 30. Internet Today â Made of many LANs and WANs â Every day new networks area added and removed â Internet services Providers (ISPs) offer services to the end users â International service providers â National service providers â Regional service providers â Local service providers
- 31. THANK YOU....!