with various data-link layer, network layer, routing and transport layer networking protocols. It has been specifically developed for undergraduate teaching."> undergraduate, teaching"> TEXT ="black" LINK="blue" VLINK="purple">  
The cnet network simulator (v1.7.7) enables experimentation with various data-link layer, network layer, routing and transport layer networking protocols. cnet has been specifically developed for, and used in, undergraduate computer networking courses taken by thousands of students since 1991. At The University of Western Australia, cnet is used primarily in Chris McDonald's Computer Networks (IT312) undergraduate unit.

cnet runs on a variety of UNIX and Linux platforms. It does not run on either Windows or the Apple Macintosh. The original and most up-to-date version of this documentation remains at

Further information available from here:

Please appreciate that there are thousands of students worldwide using cnet. I am unable to respond to individual questions about cnet, unless they are from students enrolled in a course that I'm presenting. Please ask your professor or instructor.



The following people have generously offered suggestions, pieces of code, and acted as testers, as cnet has developed over the years. A big thanks to them all:

Dr Greg Baur (University of Western Kentucky), Prof. Bruce Elenbogen (University Michigan-Dearborn), Mark Davies (University of Wellington, New Zealand), Prof. John Hine (University of Wellington, New Zealand), Dr Chris Johnson (The Australian National University), Dr David Laverell (Calvin College, Michigan), A/Prof. Phil MacKenzie (Boise State University, Idaho), Prof. Jeff Ondich (Carleton College, Minnesota), Dr Chris Pudney (The University of Western Australia), Dr Mike Robins (SMR Electronics Pty Ltd), Prof. James Wilkinson (College of Charleston, South Carolina), and my 1450 undergraduate students at The University of Western Australia and Dartmouth College who have always been able to find the last bug.

Data and Computer Communications, 6th ed., by William Stallings cnet has been selected by William Stallings to complement the material in his text Data and Computer Communications, 6th ed., published November 1999 by Prentice-Hall (Copyright 2000, 810 pp., ISBN 0-13-084370-9). This text was voted the winner of the 2000 award for long-term excellence in a Computer Science textbook, awarded by the Text and Academic Authors Association, Inc.

If you can demonstrate that you are a member of academic staff somewhere (business card, FAX on University letterhead, or official Web page), I'll email some more detailed examples to you - ones that may typically be set for student projects.

If you decide to use cnet in the teaching of an undergraduate course, or need some more info on how to, please let me know. I'd like to keep a record of sites using cnet and the types of examples and projects being attempted. I'll also be able to keep you informed of updates. Examples of some large projects, such as those written by Aric Stewart and Leema Kuhn and Robert Anderson (all supervised by Prof. Jeff Ondich), are sought.


A Network Specification Language and Execution Environment for Undergraduate Teaching, C.S. McDonald, Proc. of the ACM Computer Science Education Technical Symposium '91, San Antonio, Texas, Mar 1991, pp25-34.
Network Simulation Using User-level Context Switching, C.S. McDonald, Proc. of the Australian UNIX Users' Group Conference '93, Sydney, Sept 1993, pp1-10.

cnet was written and is maintained by Chris McDonald (