The virtual network system

The goal of our work is to give students a hands-on experience designing, deploying and debugging parts of the Internet infrastructure, such as an Internet router that routes real network traffic, or a security firewall. To do so normally requires that the students have access to snoop and generate raw network traffic, which is a risk to privacy and security. And it normally requires each student to have a dedicated computer, and to modify the kernel. The Virtual Network System (VNS) is a teaching tool designed for undergraduate and graduate networking courses. With VNS, each student can build a router (or any packet-processing device) in user-space, in their own private, protected topology, and process real Internet traffic. VNS has been used by over 500 students at Stanford and remotely from other universities. This paper describes the VNS tool, and our experiences using it in the classroom.