Using laboratory to improve understanding of 802.3 physical characteristics

When teaching computer networks as part of a computer engineering degree, emphasis is placed on higher-layer protocols while physical and data-link layers usually play a secondary role. Physical aspects of data communication are sometimes taught as an independent, not-related, topic whereas data-link concepts are ¿hard¿ to our students. We propose a new lab experience in which students can see IEEE 802.3 frames in a new way; by using standard digital oscilloscope we are able to go deeper into lower-level layers. The lab session will be divided into two parts, focusing on topics that are usually considered ¿hard¿ by our students. The first part will focus on physical aspects of a frame transmission whereas the second will focus on MAC-layer. For example, topics like physical layer synchronization, signal attenuation, 5-4-3 rule and even interframe gap are exercised at the lab session. This experience has been tested with a group of last year students; we have analyzed students ¿own perception¿ of previous knowledge of some related topics, the results from a evaluation questionnaire (a small exam given out to students) and students evaluation of this exercise.