Deadlock-Free Dynamic Network Reconfiguration Based on Close Up*/Down* Graphs

Current high-performance distributed systems use a switch-based interconnection network. After the occurrence of a topological change, a management mechanism must reestablish connectivity between network devices. This mechanism discovers the new topology, calculates a new set of routing paths, and updates the routing tables within the network. The main challenge related to network reconfiguration (the change-over from one routing function to another) is avoiding deadlocks. Former reconfiguration techniques significantly reduce network service. In addition, most recent proposals either need extra network resources (such as virtual channels) or their computation complexities are prohibitive. For up*/down* routed networks we propose a new reconfiguration method that supports a virtually unaffected network service at a minor computational cost. This method is suitable for both source and distributed routing networks, and does neither restrict the injection of packets nor the updating of routing tables during the topology-change assimilation.