Animation of computer networking concepts

A number of the key concepts in the design of computer networks lend themselves to illustration through animation. Animation can make the main features of these concepts accessible to the beginning undergraduate student as well as to more advanced students. We have identified six of these networking concepts: packet encapsulation; packet fragmentation; error control; media access in Ethernet local-area networks; domain name resolution; and the hypertext transfer protocol. We developed Java applets and accompanying materials to illustrate four of these concepts. The applets serve two roles: one role as a visual representation of different scenarios with respect to the concept in question; the second role as a vehicle for experimentation. We discuss the applets, the sequence of points each applet is designed to convey, and how the user can conduct experiments to further understand the networking concept. For the other two concepts, we show how the student can use free, easily available software to observe how the concept is implemented in the Internet.