The space formed by networked computers is often referred to as being virtual. Students of computer science need to learn about computers and networks in a hands-on way; when teaching computer security in particular, a sandbox of networked systems is required to allow them to experiment in a safe environment. This sandbox is a virtual virtual space, thus the paper’s title: “virtual square,” V2.
The V2 system is composed of virtual machines that are connected to a virtual network. Clearly, the performance of such a system suffers, but the system is very flexible, since the virtual machines can also be combined with real ones in a network. For instance, several real computers might attack a virtual server in a lab environment.
The authors present a brief overview of software for emulated hosts and virtual networks. Most of the tools described were implemented by the authors, and are available as free and open software. While the approach described by the authors is certainly a very good one, a comparison to commercially available virtual machines (such as VMware or Virtual PC) would have been nice. VMware can also be used to set up virtual machines, and it offers different modes of networking between these virtual machines.