CST 311 ---- Week 3

This week we learned about the Transport Layer. This layer resides between the application layer and the network layer. A transport layer provides for logical communication between application processes running on different hosts. With this logical communication, it can seem as if the hosts running the processes were directly connected. However, the hosts could be on opposing ends of the Earth as we know it. The transport layer converts the application-layer messages it receives from a sending application process into transport-layer packets known as transport-layer segments, which we observed in the labs of this week. 

There are two major protocols that can be used. UDP, which provides an unreliable, connectionless service to the invoking application. And there is TCP, the transmission control protocol, which provides a reliable, connection-oriented service to the invoking application. 

I also learned that extending host-to-host delivery to process-to-process delivery is called transport-layer multiplexing and demultiplexing. Tcp provides reliable data transfer and this is a major factor that ensures the data is delivered from the sending process to the receiving process.

 Above is a picture demonstrating transport-layer multiplexing and demultiplexing.

I learned so much more in the textbook, I could write much more because I truly do enjoy reading about networking, it makes me want to consider going off in that direction in my studies, because I am just so fascinated by it. It is a subject that doesn't feel heavy for me to read about, in all honesty. Through the labs of this week I learned about congestion control and did some calculations that involved RTT and MSS, and everything went fine! I also thoroughly enjoy doing the labs and they coincide with the textbook so well! I look forward to the next week of studies and beyond.