CS401 Study Guide

This study guide will help you get ready for the final exam. It discusses the key topics in each unit, walks through the learning outcomes, and lists important vocabulary terms. It is not meant to replace the course materials!

Unit 9: Networking

9a. Explain basic networking principles

  • Describe some of the basic elements involved in networking.

Computer networking refers to the ability of different computers, peripherals, and things we might not consider to be computers, to talk to each other. For example, networking allows computer users to share printers, make phone calls, use social media tools, and send and receive email.

Make sure you are familiar with the definitions for the following terms related to computer networking:

Client – a desktop computer or workstation that can obtain information and applications from a server.

Hub – a basic networking device that connects multiple computers with other network devices.

Local Operating System – the operating system that manages a desktop computer or workstation.

Network Interface Card (NIC) – the computer hardware that connects computers and devices to the computer network.

Network Operating System – the operating system that manages network resources and performs the special functions that connect computers and devices, such as to a local area network (LAN) or a wide area network (WAN) over the Internet.

Router – a networking device that exchanges data packets among computer networks. Routers direct the traffic functions on the Internet.

Server – a computer that provides data to other computers. It may serve data to systems on a local area network (LAN) or a wide area network (WAN) over the Internet. Many types of servers exist, including web servers, mail servers, and file servers.

Shared Printers and Other Peripherals – hardware resources provided to network users by servers. Resources include data files, printers, software, and other items clients share on the network.

Switch – a computer network device that connects other devices together.

Review these basic elements of networking in Introduction to Networks, Computer Networking, and Networking II.


9b. Discuss protocols and how they are used

  • What are some common networking protocols? Include their acronyms, if typically used.

Computer networking requires different tools, in the form of common software programs or protocols, so computers can communicate with each other even if they were produced by different manufacturers. This is where networking protocol standards come into play. Any manufacturer can refer to the networking protocol standard and know what their product needs to do to talk with other equipment or computers made by other manufacturers.

Here are some common networking protocols:

  1. Domain Name System (DNS)
  2. File Transfer Protocol (FTP)
  3. Hypertext Transfer Protocol (HTTP)
  4. Hypertext Transfer Protocol over SSL/TLS (HTTPS)
  5. Internet Message Access Protocol (IMAP)
  6. Internet Protocol (IP)
  7. Post Office Protocol version 3 (POP 3)
  8. Secured Shell (SSH)
  9. Simple Mail Transfer Protocol (SMTP)
  10. Simple Network Management Protocol (SNMP)
  11. Telnet
  12. Transmission Control Protocol (TCP)

Review this material in Layering and Link Layer.


9c. Explain reference models, particularly TCP/IP and OSI

  • Define the OSI 7 Layer model. What do computer programmers use it for?
  • What is the TCP/IP model? What is it used for?

The OSI/ISO 7 Layer Model

The International Organization for Standardization (ISO), an international standard-setting body, created the OSI (Open Systems Interconnection) reference model which describes the functions of a communication system. The OSI model provides a framework for creating and implementing networking standards and devices and describes how network applications on different computers can communicate through network media.

Engineers use the OSI/ISO 7 Layer model as a teaching model to explain the different functions computers have to be able to complete to communicate. They do not use this model to manufacture or build equipment.

The TCP/IP Model

The United States Defense Advanced Research Project Agency (DARPA) created the TCP/IP model in the 1970s as an open, vendor-neutral, public networking model. Just like the OSI model, it describes general guidelines for designing and implementing computer protocols. 

These computer protocols consist of four layers: network access, Internet, transport, and application.

The four TCP/IP layers cover, perform, and can be mapped alongside the OSI 7 Layer model, showing where and how they are logically equivalent even though they are distinctly different.

Engineers use the TCP/IP model to manufacture and build equipment and as a practical model for internetworking communication between devices.

OSI/ISO 7 Layer model and the TCP/IP networking communications protocol are foundational to modern computer networking. Computer engineers use the OSI model to teach and discuss the subject of networking. While they also use the TCP/IP model to discuss networking, they typically supplant this model with the OSI 7 Layer model in professional conversations. However, engineers use the TCP/IP model to build and communicate between computing devices.

Review this material in:


Unit 9 Vocabulary

  • Domain Name System (DNS)
  • File Transfer Protocol (FTP)
  • Hypertext Transfer Protocol (HTTP)
  • Hypertext Transfer Protocol over SSL/TLS (HTTPS)
  • Internet Message Access Protocol (IMAP)
  • Internet Protocol (IP)
  • Networking
  • Networking protocol
  • OSI/ISO 7 Layer Model
  • Post Office Protocol version 3 (POP 3)
  • Protocol
  • Secure Shell (SSH)
  • Simple Mail Transfer Protocol (SMTP)
  • Simple Network Management Protocol (SNMP)
  • Telnet
  • Transmission Control Protocol (TCP)