Resource partitioning in the NEPHELE datacentre interconnect

Abstract

We present heuristic algorithms for the efficient resource partitioning in the NEPHELE datacentre optical interconnect. The algorithms aim to segment the network into smaller and isolated virtual datacentres (VDCs), where all racks are able to communicate at full capacity irrespective of their placement. Since the NEPHELE architecture relies on shared optical rings, the isolation of VDC traffic is challenging. Observing its close resemblance to finding a bi-clique on a bipartite graph, which is NP-hard, we propose heuristic algorithms which find a solution by limiting either the spatial spread of racks that construct each VDC or their wavelength allocation. If a solution cannot be found, then the algorithms invoke a second de-fragmentation phase, where they re-allocate the racks of existing VDCs to concentrate them spatially and reduce traffic on the shared optical rings. It is demonstrated via simulation that the proposed heuristics can achieve very high utilization and also exhibit low VDC request blocking probability for typically expected VDC sizes