Dynamic heuristic for the recomposition of service function chain

Abstract

Network function virtualisation and software-defined networking are two emerging technologies which together enable a new service provisioning paradigm called service function chain (SFC). However, the SFC should be scalable enough to accommodate one or more service functions joining or leaving it during its lifecycle. In this work, the authors first formulate this problem as an integer linear programming (ILP) model, and then address this ILP model to obtain the optimal solution. Due to the extremely high execution time for solving the ILP model, they next proposed a dynamic heuristic to solve this problem. In particular, the proposed heuristic leverages two kinds of strategies to handle the scale-in (i.e. removing existing service functions from SFCs) and scale-out (i.e. adding new service functions to SFCs) requests. Since each SFC has a corresponding service function path (SFP) constructed, the first kind of strategy proposes to serve the arriving scale-in and scale-out requests based on the in-use SFP, while the second kind of strategy intends to optimise the in-use SFP to achieve low cost and packet loss probability proactively. Finally, the experimental results indicate that the proposed heuristic can achieve better performance than the existing algorithm.