1. The TCP/IP communication layer stack Skills: none IT concepts: protocol layers, TCP/IP, OSI This work is licensed under a Creative Commons Attribution-Noncommercial- Share Alike 3.0 License.

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

3. TCP/IP protocol layers from 1,000 feet up Application Transport Internet Data link Physical Programs that do useful work like retrieve Web pages, copy files, send and receive email, etc. Make client-server connections and optionally control transmission speed, check for errors, etc. Route data between networks Route data within the local area network Specify what medium connects two nodes, how binary ones and zeros are differentiated, etc,

4. TCP/IP from 2,000 feet up Application Program, for example, a Web client Application Program, for Example, a Web server A TCP/IP network

5. TCP/IP protocol layers from 2,000 feet up LayerFunction ApplicationDo useful work like Web browsing, email, and file transfer Four Lower layers Handle communication between the client and server

6. Terminology confusion pitfalls Some authors combine the data link and physical layers as the “network access” or the “network interface” layer. Different authors use different layer names like “network layer” instead of “internet layer.”Different authors use different layer names

7. OSI versus TCP/IP OSI (open systems interconnection) was historically significant derived by a different process and lost in the marketplace.

8. The TCP/IP communication layer stack Skills: none IT concepts: protocol layers, TCP/IP, OSI This work is licensed under a Creative Commons Attribution-Noncommercial- Share Alike 3.0 License.

9. A few questions

10. Programs that do useful work like retrieve Web pages, copy files, send and receive email, etc. Make client-server connections and optionally control transmission speed, check for errors, etc. Route data between networks Route data within the local area network Specify what medium connects two nodes, how binary ones and zeros are differentiated, etc, Do you recall the names of the TCP/IP protocol layers?

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