VDE: an emulation environment for supporting computer networking courses

Emulators have long been a valuable tool in teaching. Particularly in the OS course, emulators have allowed students to experiment meaningfully with different machine architectures. Furthermore, many such tools run in user-mode, allowing students to operate as system administrators without the concomitant security risks. Virtual Distributed Ethernet (VDE) is a system which emulates, in user-mode, all aspects of an internet, including switches, routers, communication lines, etc, in a completely realistic manner, consistent with the operation of such artifacts in the real world. VDE's can be implemented on a single computer, spread over several machines on the same LAN or scattered across the Internet. A VDE can interoperate with both real systems (via standard virtual interface/connectivity tools) and several virtual machine environments, support encryption, and actually run fast enough to support real applications. Furthermore, a VDE can interface/interoperate with real networks. VDN's have proven highly effective in supporting both undergraduate and graduate networking courses, and a wide range of student experiments and projects.