1. 8/28/2004 2. Network Models - Lin 1 CPET/ECET 355 2. Network Models Data Communications and Networking Fall 2004 Professor Paul I-Hai Lin Electrical and Computer Engineering Technology Indiana University-Purdue University Fort Wayne www.ecet.ipfw.edu/~lin

2. 8/28/2004 2. Network Models - Lin 2 2.1 Layered Tasks Sender, Receiver, and Carrier Hierarchy –Preparation –Sending –Delivering Services –Higher layer uses lower layer service

3. 8/28/2004 2. Network Models - Lin 3 2.2 Internet Model 5 Layer Model –Layer 5 Application –Layer 4 Transport –Layer 3 Network –Layer 2 Data Link –Layer 1 Physical

4. 8/28/2004 2. Network Models - Lin 4 Peer-to-Peer Processes From Figure 2.3 of Data Communications and Networking by Forouzan, 3rd

5. 8/28/2004 2. Network Models - Lin 5 Interfaces between Layers Passing data and network info (down/up) Provide modularity to a network Isolate requiring changes to the surrounding layers

6. 8/28/2004 2. Network Models - Lin 6 Organization of the Layers Network Support Layers (physical aspects) –Electrical specifications –Physical connections –Physical addressing –Transport timing –Reliability Layers –Layer 1 Physical Layer –Layer 2 Data Link Layer –Layer 3 Network layer

7. 8/28/2004 2. Network Models - Lin 7 Organization of the Layers (cont.) Transport Layer (65536 ports) –Layer 4 –TCP Transmission Control –User Datagram Protocol User Support Layer –Layer 5 Applications –File Transport Protocol –HTTP

8. 8/28/2004 2. Network Models - Lin 8 An Exchange Using Internet Model From Figure 2.4 of Data Communications and Networking by Forouzan, 3rd

9. 8/28/2004 2. Network Models - Lin 9 Physical Layer Data in the Bit Stream Data Rate Synchronization of Bits Interface & Transmission Media –Electrical Specification –Mechanical Specification Functions and Procedures for data transmission

10. 8/28/2004 2. Network Models - Lin 10 Physical Layer From Figure 2.5 of Data Communications and Networking by Forouzan, 3rd

11. 8/28/2004 2. Network Models - Lin 11 Data Link Layer A Reliable Link Error free to the upper layer (network layer) Major Tasks –Framing –Physical addressing –Flow control –Error control –Access control

12. 8/28/2004 2. Network Models - Lin 12 Data Link Layer (cont.) From Figure 2.6 of Data Communications and Networking by Forouzan, 3rd

13. 8/28/2004 2. Network Models - Lin 13 Data Link Layer – Node-to-Node Delivery From Figure 2.7 of Data Communications and Networking by Forouzan, 3rd

14. 8/28/2004 2. Network Models - Lin 14 Example 2-1: Data frame Physical addresses –Sender node – physical address 10 –Receiver node – Physical address 87 Data Trailer – extra bits for error detection

15. 8/28/2004 2. Network Models - Lin 15 Example 2-1 Data Frame (cont.) From Figure 2.8 of Data Communications and Networking by Forouzan, 3rd

16. 8/28/2004 2. Network Models - Lin 16 Network Layer Source to destination delivery of a data packet across multiple networks Upper layer - Transport layer Lower layer – Data link layer Logical addressing (IP) Routing

17. 8/28/2004 2. Network Models - Lin 17 Network Layer From Figure 2.9 of Data Communications and Networking by Forouzan, 3rd

18. 8/28/2004 2. Network Models - Lin 18 Network Layer – Source-to- Destination Delivery From Figure 2.10 of Data Communications and Networking by Forouzan, 3rd

19. 8/28/2004 2. Network Models - Lin 19 Example 2-2 Sender (on one LAN) –Network address A –Physical address 10 Receiver (on another LAN) –Network address P –Physical address 95 Router

20. 8/28/2004 2. Network Models - Lin 20 Example 2-2 From Figure 2.11 of Data Communications and Networking by Forouzan, 3rd T2 Data A P 10 20 T2 Data A P 99 33 T2 Data A P 66 95

21. 8/28/2004 2. Network Models - Lin 21 Transport Layer Responsible for process-to-process delivery of the entire message Ensure reliable and orderly of data transporting Oversee error control and flow control

22. 8/28/2004 2. Network Models - Lin 22 Transport Layer (cont.) From Figure 2.12 of Data Communications and Networking by Forouzan, 3rd

23. 8/28/2004 2. Network Models - Lin 23 Transport Layer – Major Tasks Port addressing (16-bit, 65536 ports) Message segmentation and reassembly Connection control –Connection-oriented (TCP) –Connection-less (User Datagram Protocol) Flow control Error Control

24. 8/28/2004 2. Network Models - Lin 24 Reliable Process-to-Process Delivery From Figure 2.13 of Data Communications and Networking by Forouzan, 3rd

25. 8/28/2004 2. Network Models - Lin 25 Example 2-3 Transport Layer Communication One message Chopped into two data packets The address of sending process is j The address of receiving process is k 2 data packets travel on different paths and may be out of order Reconstruct the message for layer 5

26. 8/28/2004 2. Network Models - Lin 26 Example 2-3 Transport Layer Communication (cont.) From Figure 2.14 of Data Communications and Networking by Forouzan, 3rd

27. 8/28/2004 2. Network Models - Lin 27 Application Layer Enable software of user to access the network Provide user interface and support of services Examples of services –Email –Remote log-in –Remote file transfer and access –WWW access, and more

28. 8/28/2004 2. Network Models - Lin 28 Application Layer (cont.) From Figure 2.15 of Data Communications and Networking by Forouzan, 3rd

29. 8/28/2004 2. Network Models - Lin 29 Summary of Duties From Figure 2.16 of Data Communications and Networking by Forouzan, 3rd

30. 8/28/2004 2. Network Models - Lin 30 2.3 OSI Model From Figure 2.17 of Data Communications and Networking by Forouzan, 3rd

31. 8/28/2004 2. Network Models - Lin 31 Summary Questions?