CST 311 Week 2 - 2.1 - 2.5, 2.8

This week I learned a lot about the Application Layer in the textbook. I learned that an application developer will usually choose one of the two: Client-server architecture, or peer-to-peer architecture. They both have advantages. An example of client-server architecture is the Web, FTP, Email. An example of P2P is BitTorrent. Here is a picture showing the differences between the 2:

In 2.1.2, I learned that it's not programs that communicate, but processes. 

For example, with the Web, a browser is a client process and a Web server is a server process.

A process sends messages into, and receives messages from, the network through a software interface called a socket. If the process is like the house then the socket would be like the door. 

In 2.1.3 I learned that the transport layer protocol services are classified amongst four dimensions: reliable data transfer, throughput, timing, and security. These were all discussed in detail.

In 2.1.4 I learned about TCP services and UDP services. 

In 2.1.5 I learned about application-layer protocols. These define how an application's processes, running on different end systems, pass messages to each other. 

2.2 talked about the Web and HTTP. I learned an overview about http, non-persistent and persistent connections, HTTP message format, HTTP response message, cookies, and web caching.

2.3 was about electronic mail in the internet. There are 3 major components: user agents, mail servers, and the Simple Mail Transfer Protocol (SMTP). I also learned about DNS, the internet's directory service (and this was exemplified in great detail in this week's lab). 

There was much more discussed, but this is a brief overview.

My thoughts on this week's learning: I actually am really enjoying learning all the ins and outs of the Internet and how it works under the surface. The labs are very hands-on and the reading is engaging. Another week of success, and I look forward to enjoying this class even more in the future!