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. 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

5. TCP/IP layers LayerFunction ApplicationDo useful work like Web browsing, email, and file transfer TransportTransport data between application clients and servers 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

6. Establish the temporary connection between the two computers Packetize the data Make sure the packets get to the correct program on the receiving computer Optionally check for and correcting transmission errors or out of sequence packets Optionally slow transmission if the receiving computer cannot keep up with the data flow Why optional? Transport layer Transport data between application clients and servers

7. Two transport layer protocols TCP (reliable) or UDP (unreliable)

8. ? ? ? (geek symbol for a router) Internet Layer Route packets between networks (inter network)

9. Internet Layer Route packets between networks (inter network)

10. Data link Layer Send data within the local area network

11. or PhysicalSpecify hardware characteristics and ways to differentiate between ones and zeros

12. 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.

13. Summary LayerFunction ApplicationDo useful work like Web browsing, email, and file transfer TransportTransport data between application clients and servers 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

14. 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.

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

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

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