Optimal VNF Chains Management for Proactive Caching

Notwithstanding the significant attention that network function virtualization architectures received over the last few years, little attention has been placed on cases where proactive caching is considered within a service chain. Caching algorithms have been developed independently from virtual network function (VNF) chaining schemes, and as we explain in detail in this paper such operation might lead to sub-optimal overall network and service performance. Since caching of popular content is envisioned to be one of the key adopted technologies in emerging 5G networks to increase network efficiency and overall end user perceived quality of service, we explicitly consider the interplay and subsequent optimization of caching-based VNF service chains. To this end, a mathematical programming framework is proposed tailored to VNF caching chains and, in addition, we detail a scale-free heuristic algorithm to provide competitive solutions for large network instances since the problem itself can be seen as a variant of the classical NP-hard uncapacitated facility location problem. A wide set of numerical investigations is presented for characterizing the attainable system performance of the proposed schemes.