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Hunkar Can Tunc

Publications and source records attributed to Hunkar Can Tunc.

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DyNetKAT: An Algebra of Dynamic Networks

We introduce a formal language for specifying dynamic updates for Software Defined Networks. Our language builds upon Network Kleene Algebra with Tests (NetKAT) and adds constructs for synchronisations and multi-packet behaviour to capture the interaction between the control- and data-plane in dynamic updates. We provide a sound and ground-complete axiomatisation of our language. We exploit the equational theory to provide an efficient reasoning method about safety properties for dynamic networks. We implement our equational theory in DyNetiKAT -- a tool prototype, based on the Maude Rewriting Logic and the NetKAT tool, and apply it to a case study. We show that we can analyse the case study for networks with hundreds of switches using our initial tool prototype.

cs.NI

Explaining Safety Failures in NetKAT

This work introduces a concept of explanations with respect to the violation of safe behaviours within software defined networks (SDNs) expressible in NetKAT. The latter is a network programming language based on a well-studied mathematical structure, namely, Kleene Algebra with Tests (KAT). Amongst others, the mathematical foundation of NetKAT gave rise to a sound and complete equational theory. In our setting, a safe behaviour is characterised by a NetKAT policy, or program, which does not enable forwarding packets from an ingress i to an undesirable egress e. We show how explanations for safety violations can be derived in an equational fashion, according to a modification of the existing NetKAT axiomatisation. We propose an approach based on the Maude system for actually computing the undesired behaviours witnessing the forwarding of packets from i to e as above. SDN-SafeCheck is a tool based on Maude equational theories satisfying important properties such as Church-Rosser and termination. SDN-SafeCheck automatically identifies all the undesired behaviours leading to e, covering forwarding paths up to a user specified size.

cs.FL