Designing a Federated Testbed as a Distributed System
Proceedings of the 8th International ICST Conference on Testbeds and Research Infrastructures (Tridentcom) 2012.
Traditionally, testbeds for networking and systems research have been stand-alone facilities: each is owned and operated by a single administrative entity, and is intended to be used independently of other testbeds. However, this isolated facility model is at odds with researchers' ever-increasing needs for experiments at larger scale and with a broader diversity of network technologies. The research community will be much better served by a federated model. In this model, each federated testbed maintains its own autonomy and unique strengths, but all federates work together to make their resources available under a common framework.
Our challenge, then, is to design a federated testbed framework that balances competing needs: We must establish trust, but at the same time maintain the autonomy of each federated facility. While providing a unified interface to a broad set of resources, we need to expose the diversity that makes them valuable. Finally, our federation should work smoothly in a coordinated fashion, but avoid central points of failure and inter-facility dependencies. We argue that treating testbed design as a federated distributed systems problem is an effective approach to achieving this balance. The technique is illustrated through the example of ProtoGENI, a system we have designed, built, and operated according to the federated model.