VNF chain allocation and management at data center scale

Recent advances in network function virtualization have prompted the research community to consider data-center-scale deployments. However, existing tools, such as E2 and SOL, limit VNF chain allocation to rack-scale and provide limited support for management of allocated chains. We define a narrow API to let data center tenants and operators allocate and manage arbitrary VNF chain topologies, and we introduce NetPack, a new stochastic placement algorithm, to implement this API at data-center-scale. We prototyped the resulting system, dubbed Daisy, using the Sonata platform. In data-center-scale simulations on realistic scenarios and topologies that are orders of magnitude larger than prior work, we achieve in all cases an allocation density within 96% of a recently introduced, theoretically complete, constraint-solver-based placement engine, while being 82x faster on average. In detailed emulation with real packet traces, we find that Daisy performs each of our six API calls with at most one second of throughput drop.