Types of computer networks, protocols and standards

Types of computer networks, protocols and standards

1. 1. Computer Networks Introduction to computer networks
2. 2. Objectives • Define computer networks • Classify computer networks • Protocols & Standardization
3. 3. Computer Networks ? • A large number of separate but interconnected computers do the specific job. • A collection of autonomous computers interconnected by a single technology.
4. 4. Interconnected ? Two computers are said to be interconnected if they are able to exchange information.
5. 5. Types of Networks Classification based on transmission technology Broadcast links. Point-to- point links.
6. 6. Broadcast networks • Have a single communication channel that is shared by all the machines on the network. Host H1 H2 H3 H4 H5H6 Communication channel
7. 7. Broadcast networks • Short messages (also called packets) sent by any machine are received by all the others. • An address field within the packet specifies for whom it is intended. • Upon receiving a packet, a machine checks the address field. • If the packet is intended for the receiving machine, it processes the packet; otherwise it is just ignored. • This mode of operation is called broadcasting
8. 8. Bus Topology Ring Topology
9. 9. point-to-point networks • Many connections between individual pairs of machines. • To go from the source to the destination, a packet on this type of network may have to first visit one or more intermediate machines.
10. 10. Note: • As a general rule, smaller, geographically localized networks tend to use broadcasting, whereas larger networks usually are point-to-point
11. 11. Types of Networks Classification based on Scale (physical size) •LAN • MAN •WAN
12. 12. Local Area Networks • Within a single building or campus of up to a few kilometers in size. • They are widely used to connect personal computers and workstations in company offices and factories to share resources (e.g., printers) and exchange information.
13. 13. Three characteristics of LANs size, transmission technology, topology. few kilometers in size single cable , speeds of 10 Mbps to 100 Mbps Bus, Ring
14. 14. Metropolitan Area Networks • A MAN covers a city. • Ex:- cable television network
15. 15. Wide Area Networks • WAN, spans a large geographical area, often a country or continent. • The hosts are connected by a communication subnet, or just subnet for short. • The hosts are owned by the customers, whereas the communication subnet is typically owned and operated by a telephone company or Internet service provider.
16. 16. Subnet • The job of the subnet is to carry messages from host to host, just as the telephone system carries words from speaker to listener. • The subnet consists of two distinct components: –transmission lines and –switching elements.
17. 17. Transmission lines move bits between machines. They can be made of copper wire, optical fiber, or even radio links. Switching elements are specialized computers used to connect two or more transmission lines.
18. 18. Principle of Subnet • When a packet is sent from one router to another via one or more intermediate routers, the packet is received at each intermediate router in its entirety, stored there until the required output line is free, and then forwarded. • A subnet using this principle is called a store- and-forward or packet-switched subnet.
19. 19. • Routing algorithms are used to choose the path between source and destination.
20. 20. Wireless Networks • wireless networks can be divided into three main categories: 1. System interconnecti on 2. Wireless LANs 3. Wireless WANs.
21. 21. System interconnection • Connecting the components of a computer together using short-range radio. • Bluetooth to connect the components without wires. • Bluetooth also allows digital cameras, camcorders, scanners, and other devices to connect to a computer by merely bringing them within range.
22. 22. System interconnection using Bluetooth Configuration
23. 23. Wireless LANs • These are systems in which every computer has a radio modem and antenna with which it can communicate with other systems.
24. 24. Wireless WAN • Example:- cellular networks • cellular wireless networks are like wireless LANs, except that the distances involved are much greater and the bit rates much lower.
25. 25. Protocols & Standardization • Human analogy
26. 26. What is a protocol? • The formal specifications and conventions that govern and control the communications and data exchange. • Protocols are the standards for communications, networking, and internet networking..
27. 27. Standards • Traditional standards –Ex: TCP/IP • Judicial Standard o ISO/OSI