1. Skills: none Concepts: local area network, router, inter network, the TCP/IP layered software “stack”, layer functions, layer protocols, dumb versus smart networks This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License. TCP/IP from 10,000 feet

2. Where does this topic fit? Internet concepts – Applications – Technology – Implications Internet skills – Application development – Content creation – User skills

3. TCP/IP from the outside Application Program, for example, a Web client Application Program, for Example, a Web server A TCP/IP network

4. Local area networks LAN

5. A router at the edge ? ? ?

6. From LAN to Internet to LAN

7. The Internet a network of networks

8. The path between two hosts

9. Crossing the LAN LAN R

10. From the LAN to the ISP’s router

11. Forward to next network

14. Reaches the destination network

15. Client Server Delivered by the data link layer

16. A router goes down

17. Net routes around problems

18. TCP/IP, the very big picture Layer Function Application programs Do useful work like Web browsing, email, and file transfer TCP/IP communication software Handle communication between the client and server

19. Function of each layer LayerFunction ApplicationDo useful work like Web browsing, email, and file transfer TransportTransport data between application programs running on two hosts InternetRoute packets between networks (inter network) Data linkSend data within the local area network PhysicalSpecify hardware characteristics and ways to differentiate between ones and zeros

20. Function of each layer LayerFunction ApplicationDo useful work like Web browsing, email, and file transfer TransportTransport data between application programs running on two hosts InternetRoute packets between networks (inter network) Data linkSend data within the local area network PhysicalSpecify hardware characteristics and ways to differentiate between ones and zeros

21. Function of each layer LayerFunction ApplicationDo useful work like Web browsing, email, and file transfer TransportTransport data between application programs running on two hosts InternetRoute packets between networks (inter network) Data linkSend data within the local area network PhysicalSpecify hardware characteristics and ways to differentiate between ones and zeros

22. Transport layer protocols TCP (transmission control protocol) or UDP (universal datagram protocol)

23. Data link layer protocols Ethernet or Wifi Ethernet or Wifi

24. Internet layer protocol IP (the internet protocol)

25. Application layer protocols Different protocols for each application

26. Physical layer standards or

27. Protocols at each layer LayerProtocol ApplicationMany depending upon the application TransportTCP or UDP InternetIP Data linkEthernet and WiFi most common PhysicalMany wireless, copper wire, optical fiber, etc.

28. By design, the Internet is dumb The InternetThe telephone network The telephone network is smart

29. Summary LayerFunction ApplicationDo useful work like Web browsing, email, and file transfer TransportTransport data between application programs running on two hosts InternetRoute packets between networks (inter network) Data linkSend data within the local area network PhysicalSpecify hardware characteristics and ways to differentiate between ones and zeros

30. Self-study questions 1.Do you have a LAN at home? How many computers connect to it 2.There is only one connection leading out from your home router – where does it forward packets to? 3.When you connect to the Internet using a mobile device like a phone or a tablet, are you connecting to a network that is connected to the Internet? Explain. 4.We saw that there were two commonly protocols at the transport layer – TCP for reliable communication and UDP for fast, but unreliable communication. Which would an application programmer use for a file-transfer program? Which would an application programmer use for a streaming video program? Explain your answers.

31. Application Physical Do you recall the names of the TCP/IP protocol layers?

32. Do you recall the functions of the software at each layer? Application: Transport: Internet: Data link: Physical:

33. Do you recall the protocol(s) used at each layer? Application: Transport: Internet: Data link: Physical:

34. Resources