Data Communication (CS 455) - Spring 2026

• Lecture Time: Monday/Wednesday 10:00-11:15 am, PS 152
• Office Hours: Wednesdays, 2:00-3:00 pm, SB 218E
• Prerequisites: CS 351 Systems Programming
• Workload: 3 credit hours

Course Description

The modern Internet serves as a foundational infrastructure enabling global communication, commerce, research, and entertainment. It is built upon a stack of interoperating network technologies, ranging from fiber-optic backbones and BGP routing to cellular networks, DNS, and content delivery networks. Together, these technologies create a resilient, scalable, and ubiquitous platform that supports everything from real-time multimedia to cloud computing and everyday online services.

This course introduces the core principles of computer networks, with a particular focus on how the Internet operates. Students will explore the first four layers of the OSI protocol stack—Physical, Data Link, Network, and Transport—gaining a deep understanding of how data is transmitted and routed for a variety of applications and use cases. Through theoretical insights and practical assignments, students will develop a comprehensive understanding of how modern computer networks and the Internet function.

Course Objectives

By the end of the semester, students will be able to:

• Explain the structure of modern network architectures, including the roles and interactions of layers in the ISO/OSI model.
• Describe the functions and applications of key Internet protocols such as HTTP, TCP, UDP, IP, and Ethernet.
• Develop and analyze end-to-end Internet applications, focusing on reliable data transfer and congestion-control mechanisms.
• Understand the design of the Internet’s architecture and the principles behind routing algorithms and protocols.
• Explain how data is transmitted at the physical layer and how link-layer protocols enable media access and local communication.
• Demonstrate foundational knowledge of wireless networking technologies and principles.