Using Java to teach networking concepts with a programmable network sniffer

A crucial part of the Networking course is the examination of and experimentation with network traffic data. Most standalone network traffic sniffers are quite expensive and those freely available on general purpose platforms (e.g., Linux or Windows) are quite cryptic. Because of this, we have developed NetSpy: a Java-based network sniffer that allows plug-in Java modules to analyze network data. These modules are written by students as part of their experimentation with traffic data. This paper describes the NetSpy system and the way we use this in Networking class.