1. CSC 412 - Networking Scott Heggen

2. Agenda Finish 4 + 1 TCP – Part 1

3. Let’s Review What does the network layer do? What does the data link layer do? What does the physical layer do?

5. Data 01010101100010110101 10100010110010110101 011010101100101

6. Data.html

7. HTTP

8. HTTP, Data

9. TCP, Source:80, Destination:1030

10. IP, Source:8.1.1.1, Destination:130.4.3.3 TCP, HTTP, Data

11. Ethernet, Source:0010.1111.1111, Destination:0030.3333.3333 IP, TCP, HTTP, Data FCS

12. Data

14. Ethernet, Source:0010.1111.1111, Destination:0030.3333.3333

15. Data

17. Ethernet, Source:0010.1111.1111, Destination:0030.3333.3333

18. Data IP, Source:8.1.1.1, Destination:130.4.3.3 R1(config)# ip route 130.4.0.0 255.255.0.0 200.55.99.251

19. Data Ethernet, Source:0030.3333.3334 Destination:0040.4444.4444

20. Data

22. Ethernet, Source:0030.3333.3334 Destination:0040.4444.4444

23. Data IP, Source:8.1.1.1, Destination:130.4.3.3

24. Data Ethernet, Source:0040.4444.4445 Destination:0050.5555.5555

25. Data

27. Ethernet, Source:0040.4444.4445 Destination:0050.5555.5555

28. Data IP, Source:8.1.1.1, Destination:130.4.3.3

29. Data Ethernet, Source:0050.5555.5556 Destination:0020.2222.2222

30. Data

33. Ethernet, Source:0050.5555.5556, Destination:0020.2222.2222

34. Data

37. Ethernet, Source:0050.5555.5556, Destination:0020.2222.2222 IP, TCP, HTTP, Data FCS

38. IP, Source:8.1.1.1, Destination:130.4.3.3 TCP, HTTP, Data

39. HTTP, Data TCP, Source:80, Destination:1030

40. HTTP, Data

41. Data.htmlHTTP

42. Data.html

43. Data 01010101100010110101 10100010110010110101 011010101100101

45. Reflecting on this process so far… Do any of the bottom three layers handle error correction? Do any of the bottom three layers handle in-order delivery? Do any of the bottom three layers handle delivery of data to the correct device? Do any of the bottom three layers handle delivery of data to the correct process within the device? Do any of the bottom three layers handle controlling the flow of data (slowing down/speeding up data transfer rate??) Do any of the bottom three layers handle breaking up data into smaller segments?

46. Transport Layer The transport layer does all of those things (except delivery of data to the correct device; that was network layer (remember routing?!!?)) Flow control (using windowing) In-order delivery (reassembling segments into the correct order) Error recovery (lower layers handled error detection only; transport actually fixes it!) Segmentation (other layers do break the message into smaller chunks, but transport layer does it better) Identifies applications within a device via port numbers