Peter presented our paper on demonstrating the ability of the network to compute at WRIPE 2013. The paper itself is available here. The slides are also available
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Ensuring correct network behavior is hard. Previous state of the art has demonstrated that analyzing a network containing middleboxes is hard. In this paper, we show that even using only statically configured switches, and asking the simplest possible question – “Will this concrete packet reach the destination?” – can make the problem intractable. Moreover, we demonstrate that this is a fundamental property because a network can perform arbitrary computations. Namely, we show how to emulate the Rule 110 cellular automaton using only basic network switches with simple features such as packet matching, header rewriting and round-robin loadbalancing. This ultimately means that analyzing dynamic network behavior can be as hard as analyzing an arbitrary program.