1. TCP/IP: the transport layer Skills: none IT concepts: layered protocols, transport layer functions, TCP and UDP protocols, isochronous applications This work is licensed under a Creative Commons Attribution-Noncommercial- Share Alike 3.0 License.

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

3. The big picture Client Server Application programs communicate using TCP/IP

4. 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,

5. A C B → A B C Transport layer (TCP) Establish connections Slow transmission Check for errors Reorder packets Which application (port)? ftp, web, send email, read email, iTunes, bit torrent, Skype … (Transmission control protocol)

6. Transport layer (UDP) Establish connections Which application (port)? ftp, web, send email, read email, itunes, bit torrent, Skype … (User datagram protocol)

7. UDP sounds lame No error checking, reordering of packets or slowing the transmission rate -- Does UDP have an advantage over TCP? Web clients and servers use TCP and VoIP programs use UDP – why?

8. Answers UDP is faster than TCP. VoIP is an isochronous application, so errors cannot be corrected.

9. TCP/IP: the transport layer Skills: none IT concepts: layered protocols, transport layer functions, TCP and UDP protocols, isochronous applications This work is licensed under a Creative Commons Attribution-Noncommercial- Share Alike 3.0 License.

10. Another question Would a video conferencing application use UDP or TCP for transport? Explain your answer.