CST 311 Computer Networks - Week 2

Week 2 Overview:

This week focused on the application layer, where user-level network programs operate. We learned the principles behind network applications, like how clients and servers communicate through sockets using established protocols. The lectures went deep into HTTP, explaining how web browsers and servers exchange data through request and response messages, covering topics like persistent vs non-persistent connections and status codes. We also explored the Domain Name System (DNS), understanding how human-readable domain names are translated into IP addresses through hierarchical servers. The labs were very hands-on: in Wireshark HTTP, we analyzed browser-server communication, while in Wireshark DNS, we captured and examined DNS query and response packets in real time. Together, this week tied theory and practice, showing how core Internet applications actually function behind the scenes.

A major part of this week was Programming Assignment 1, where we practiced socket programming in Python using UDP and TCP. We modified client and server scripts to send user-input messages, convert them to uppercase on the server, and communicate across Mininet hosts. This assignment introduced hands-on experience with the client-server model, message passing, and network setup preparing us for more advanced coding in later weeks.