1. 1 Introduction Computer Networks

2. 2 Motivation and Scope Computer networks and internets: an overview of concepts, terminology and technologies that form the basis for digital communication in private corporate networks the the global Internet.

3. 3 Motivation for Networks Information Access Sharing of Resources Facilitate Communications

4. 4 What a Network Includes Transmission hardware Special-purpose hardware devices interconnect transmission media control transmission run protocol software Protocol software encodes and formats data detects and corrects problems

5. 5 What a Network Does Provides communication that is Reliable Fair Efficient From one application to another

6. 6 What a Network Does [continued] Automatically detects and corrects Data corruption Data loss Duplication Out-of-order delivery Automatically finds optimal path from source to destination

7. 7 Data Communication versus Networking With only two nodes, mostly EE issues. Ñ With more than two nodes, lot more issues!

8. 8 Direction of Transmission Point to PointBroadcast

9. 9 Network Topologies

10. 10 Transmission Media Wireline String Garden Hose Copper Twisted Pair Coax Optical Fiber Wireless Sound Light and mirrors Infrared RF Microwave

11. 11 Network Scope Local Area Network (LAN) Metropolitan Area Network (MAN) Wide Area Network (WAN)

12. 12 Data Transmission Serial Parallel

13. 13 Multiplexing

14. 14 Communication Modes Simplex Half-duplex Full-duplex

15. 15 Connection-oriented versus Connectionless Connection Setup Data Transfer Connection Termination Data Transfer

16. 16 Circuit Switching versus Packet Switching Dedicated fixed bandwidth route fixed at setup idle capacity wasted network state Best Effort end-to-end control multiplexing technique re-route capability congestion problems

17. 17 Examples Public Switched Telephone Network Internet Postal Service Train Car and highway system

18. 18 Standards Hardware Software Protocols Advantages and Disadvantages Proprietary, De Facto, De Jure Standards Bodies IETF, IEEE, OSI, ANSI, ATM Forum, etc.

19. 19 Protocols Rules, standards and etiquette Metric System English Dinner party Morse Code TCP/IP HTML

20. 20 Layering

21. 21 Headers, Data and Trailers

22. 22 Encapsulation

23. 23 ISO OSI Reference Model 7: Application Layer 6: Presentation Layer 5: Session Layer 4: Transport Layer 3: Network Layer 2: Data link Layer 1: Physical Layer

24. 24 Interfaces and Services PDUs SDUs SAPs Peer communications Service Primitives etc... read Tanenbaum 1.3.3 and 1.3.5

25. 25 TCP/IP Model 5: Application Layer 4: Transport Layer 3: Network Layer 2: Data link Layer 1: Physical Layer

26. 26 TCP/IP versus OSI "Rough consensus and running code ” Simplicity Time to market Availability

27. 27 Network Classification Physical medium: copper, fiber, wireless Scope: LAN, MAN, WAN Topology: bus, star, ring, mesh Switching style: circuit, packet Application: voice, data, video Protocol: IP, OSI, Ethernet, ATM Transmission rate: 10Mb/s, Gigabit

28. 28 Terms I (we) Often Use Frames: think data link layer Packets: think network layer Datagrams: think IP Segments: think TCP Cells: think ATM Layer : refer to reference models

29. 29 The End-to-End Argument "End-to-End Arguments in System Design ” J.H. Saltzer, D.P. Reed, and D.D. Clark http://web.mit.edu/Saltzer/www/publications/