The Network Workbench: network simulation software for academic investigation of Internet concepts

Simulation offers significant advantages as a basis for academic projects i n computer networking. Because many unimportant details can be abstracted a way, and also because simulations can be completely repeatable, it is possi ble to address the same concepts more quickly than is possible with actual networks. At the same time, students who program a protocol for a network s imulator come to understand the protocol much better than if they learn onl y from reading and lectures. This paper reports on a new network simulator, the Network Workbench, which is intended for use in the academic environme nt. It is based on discrete event simulation and structured around a five-l ayer stack abstracted from the Internet protocols (TCP/IP family). While th e Workbench is less powerful than some tools used for investigation of larg er networks or more complex protocols, it has compensating advantages. Its use can be learned quickly and it is sufficiently powerful, comprehensive, and extensible to allow investigation of a considerable range of problems. The Workbench, which is available to the academic community under no-cost l icense, includes a set of protocol programming exercises for introductory n etworking courses and it also has proved usable for more advanced student r esearch projects. This paper describes the philosophy behind the Workbench, gives a brief outline of its history, explains its internal structure, and describes its use in computer network teaching and research. (C) 2000 Else vier Science B.V. All rights reserved.