Using a protocol analyzer to introduce communications protocols.

A conceptual understanding of the functionality implemented in layers 1 to 4 of the OSI reference model and of the relationships among the layers when devices are communicating is necessary for any technical work in networking. This paper describes how students are introduced to communications protocols during the initial three and one-half weeks of a first networking course. A protocol analyzer is used in the one-hour labs to examine communications between Linux and Windows XP virtual machines running under VMware Workstation. The goals of the labs are to reduce the level of abstraction and to provide a foundation upon which students can develop their understanding. The paper describes the lab exercises and summarizes the accompanying assignments and lectures that build upon what students have observed in their lab work. Students are introduced to the Ethernet, ARP, IP, ICMP, UDP and TCP protocols.