Efficient Routing Algorithm Design for Large DetNet
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Deterministic Networking (DetNet) is a rising technology that offers deterministic delay & jitter and zero packet loss regardless of failures in large IP networks. In order to support DetNet, we must be able to find a set of low-cost routing paths for a given node pair subject to delay-range constraints. Unfortunately, the Delay-Range Constrained Routing (DRCR) problem is NP-Complete. Existing routing approaches either cannot support the delay-range constraints, or incur extremely high computational complexity. We propose Pulse+, a highly scalable and efficient DRCR problem solver. Pulse+ adopts a branch-and-bound methodology and optimizes its pruning strategies for higher efficiency. We also integrate Pulse+ with a divide-and-conquer approach and propose CoSE-Pulse+ to find a pair of active/backup paths that meet DetNet's delay-range and delay-diff constraints. Both Pulse+ and CoSE-Pulse+ offer optimality guarantee. Notably, although Pulse+ and CoSE-Pulse+ do not have a polynomial worst-case time complexity, their empirical performance is superior. We evaluate Pulse+ and CoSE-Pulse+ against the K-Shorst-Path and Lagrangian-dual based algorithms using synthetic test cases generated over networks with thousands of nodes and links. Both Pulse+ and CoSE-Pulse+ achieve significant speedup. To enable reproduction, we open source our code and test cases at [1].
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