| operating and window systems |
XView | Motif | TclTk | ASCII |
|---|---|---|---|---|
| DEC OSF/1 | y | y | y | y |
| SGI IRIX-5 | n | y | y | y |
| Linux (a.out) | y | n | y | y |
| Solaris 2.x | y | n | y | y |
| SunOS 4.1.x | y | y | y | y |
with Linux (ELF), MacOS 7.5, and Win-32 as the next targets. We are extremely grateful to the Apple University Consortium for providing a Power Macintosh 7500/100 on which we will further develop cnet in 1996.
cnet either displays the entire network under XView, Motif or TclTk or runs rather less visually on an ASCII terminal. Under the X-window system, cnet provides a graphical representation of the network under execution and permits a number of attributes of the network to be modified while the simulation is running. Nodes may be selected with the mouse resulting in a sub-window being displayed containing the output and statistics of that node. The node's attributes of message rates and sizes may be modified while the network is running by selecting further buttons. Similarly, the default attributes of all nodes in the network may be simultaneously modified by selecting and changing global attribute buttons. From a menu each node may be forced to reboot, (impolitely) crash, (politely) shutdown and reboot, pause and (hardware) fail.
Selecting a link results in a sub-window being displayed containing statistics for that link. Links are bidirectional, so ``selecting a link'' means clicking on the link near the end of its source. The link-based attributes of costs and probabilities of error may be modified while the network is running by dragging sliders. Similarly, the attributes of all links in the network may be simultaneously modified by selecting and changing global link attributes.
From within your protocols,
the current node and link attributes
(as possibly modified via the windowing interface)
are available to each node in C data structures and variables
declared in cnet's header file
cnet requires network protocols to be written in either the K&R or ANSI-C programming language and supports their execution within a single UNIX process. Protocols are invoked directly by cnet itself - not interpreted. Protocols do not need to contain any windowing code. In addition, different Application and Physical Layers may be provided which exhibit varying statistical characteristics of message generation and data transmission.
| Dr Greg Baur | University of Western Kentucky |
| Prof. John Hine | University of Wellington, New Zealand |
| Dr Chris Johnson | The Australian National University |
| Dr David Laverell | Calvin College, Michigan |
| Prof. Jeff Ondich | Carleton College, Minnesota |
| Dr Chris Pudney | The University of Western Australia |
| Mike Robins | The University of Western Australia |
| Prof. James Wilkinson | College of Charleston, South Carolina |
If you can prove to me that you're a member of academic staff somewhere (business card or FAX on University letterhead), 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 keep in touch. 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. Excellent examples, such as those written by Aric Stewart and supervised by Prof. Jeff Ondich, and testimonials are welcome.