An Internet measurement platform for the e-learning community
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FORGE (http://ict-forge.eu/) was a European project that ran from 2013 to 2016 that developed the use of computer networking testbeds in e-learning. Through FORGE,
teachers and students were given access to testbeds from the European Commission’s FIRE initiative, and were able to create and execute scientific experiments on these testbeds in ways that were suitable to the classroom or self-study. The e-learning tools developed by FORGE have been made available as open educational resources.
We describe our work in FORGE, which consisted of making the PlanetLab Europe testbed (http://www.planet-lab.eu/) available to a MOOC on internet measurements, so that MOOC students could conduct lab exercises in a real-world environment. The MOOC is described here: https://www.fun-mooc.fr/courses/inria/41011/session01/about
Those who are familiar with PlanetLab know that it offers SSH access to a command line environment in which one has root privileges on Linux virtual machines at servers around the world. This sort of access is appropriate for researchers engaging in long-term scientific experiments, but was ill adapted for students in this mooc for a number of reasons, among them: offering individual PlanetLab Europe accounts to 1800 students was not scalable and was not compatible with the privacy policy of the mooc platform; purely anonymous access would be incompatible with the PlanetLab security policies; the mooc students were a diverse lot and we could not count upon their knowledge of the Linux command line environment; there was a risk of flash crowd effects disrupting PlanetLab Europe’s nodes and servers.
Our solution was to develop a dedicated client-server system for mooc measurements including ping, traceroute, and iperf (this latter requiring the coordination of iperf processes on two separate PlanetLab nodes at a time). The client component, run as part of the mooc environment, provided an individualized control panel which each student could use to request measurements and see their own results. The server system is accessed through a RESTful webservices interface. The server does not learn the identities of the students, but a chain of responsibility is maintained, in case of any disruptive measurements, as the mooc administrators can identify their own students on the basis of job numbers provided them by the PlanetLab Europe administrators. The server maintains a queue of measurement requests and feeds them to PlanetLab Europe nodes at a controlled rate. Some basic sanity checks are performed to reduce the potential for disruptive measurements. The server returns standard output, standard error, the process return code, and beginning and ending timestamps for the measurement. This client-server system is currently being extended to enable measurements in other courses and on other testbeds