BeNNS: A Surrogate Model for Hybrid Online-Offline Evolution of SFC Embedding

Abstract: Service Function Chains (SFCs) enable programmatic control of the functions and services in a computer network. By leveraging Software Defined Networking to control the links between virtualised network functions, SFCs provide a scalable approach to dealing with the increased pressures on network operation and management. Unfortunately, the challenge of embedding SFCs onto the underlying physical network and compute infrastructure is an NP-hard problem. Genetic Algorithms (GAs) have been used to address this issue, but they require significant time to evaluate solution quality (fitness) \textit{online}, with most solutions instead adopting \textit{offline} simulations or analytical evaluations. To enable online use of GAs in solving the SFC embedding problem, we introduce a hybrid online-offline approach to evaluate generated solutions. At the core of this is BeNNS--a topology, traffic, and SFC-embedding agnostic surrogate model that approximates fitness. We evaluate our approach across six experiments, varying available resources and traffic loads. Our results demonstrate that our approach is capable of exploring thousands of potential configurations and generating deployable solutions in 36.8 minutes on average, compared to online-only approaches, which take 17.9 hours on average to explore tens of solutions, which do not converge on an optimal solution.