cnet Network Simulator

cnet Network Simulator (v2.0.10) is a cool tool that lets you play around with different networking protocols like data-link, network, routing, and transport layers. You can create networks using all kinds of point-to-point links and IEEE 802.3 Ethernet segments. Since 1991, cnet has been a go-to for many undergrad computer networking classes all over the world. For example, at The University of Western Australia, it’s mainly used in Chris McDonald’s course called Computer Networks (IT312).

Features of cnet

One of the great things about cnet is how it shows your entire network. You can use Tcl/Tk to get a nice graphical view, or you can keep it simple with an ASCII terminal. When using Tcl/Tk, you’ll see a visual representation of your network while it runs, and you can tweak various settings on the fly! Want to change message sizes or generation rates? Just click on the node with your mouse, and you'll get a sub-window that shows output and protocol stats.

Control Your Network Like a Pro!

You can even reboot nodes or make them crash (not too polite!) or shut them down nicely before rebooting again. There are lots of options to pause nodes or force hardware failures too—it's pretty flexible!

System Requirements

If you're running cnet on a Linux(ELF) system, make sure you have the free libelf package installed. Most newer Linux systems already come with this package if they have version 2.0 kernels or higher. If yours doesn’t have it yet, installing libelf globally will help out a lot! You'll also find that cnet comes with its own copy of libelf.

If you're on SunOS, aim for Release 4.1.2 or newer; if you’re still stuck on Release 4.1.1, you need to grab Sun-Patch-ID#100257-03 from way back in '91—time to upgrade!

For those using SGI-IRIX machines, stick with Release 5 or 6 since Release 4 is outdated now.

Older Linux systems using .aout formats are not supported anymore either.

The good news? cnet works well with most versions of Tcl/Tk like (Tcl7.X+Tk3.X), (Tcl7.X+Tk4.X), (Tcl8.0+Tk8.0), and (Tcl8.3+Tk8.3). So give it a try! You can download cnet here.