1. An Introduction to Computer Networks Amitava Nag Assistant Professor Dept. of IT, AOT

2. 1. What is communication? 2. What is data communication? Ans: Data communication is the exchange of data between two devices via some form of transmission medium.

3. 3 Data Communication Model Network SourceDestination

4. 4 Simplified Communication Model

5. 5 Simplified Data Communications Model

6. 6 Components Message –Information (data to be transmitted Sender –That sends the data Medium –Physical path that carries data Receiver –Receives data in form of signal Protocol –A set of rules that governs data communications.

7. 7 Networking Point to point communication not usually practical –Devices are too far apart. –Large set of devices would need impractical number of connections. Solution is a communications network.

8. 8 Simplified Network Model

9. Computer Network A communication system for connecting computers /hosts and share resources

10. 10 Why Networking? Sharing information — i.e. data communication Do you prefer these? Or this?

11. Why Networking? Why?  Better connectivity  Better communication  Better sharing of resources  Bring people together  Overcome geographic limits  Access remote data Goal: Universal Communication (any to any)

12. 12 How many kinds of Networks? Depending on one’s perspective, we can classify networks in different ways Based on transmission media: Wired (UTP, coaxial cables, fiber-optic cables) and Wireless Based on network size: LAN and WAN (and MAN) Based on management method: Peer-to-peer and Client/Server Based on topology (connectivity): Bus, Star, Ring …