  Notwithstanding the significant research effort Network Function
Virtualization (NFV) architectures received over the last few years little
attention has been placed on optimizing proactive caching when considering it
as a service chain. Since caching of popular content is envisioned to be one of
the key technologies in emerging 5G networks to increase network efficiency and
overall end user perceived quality of service we explicitly consider in this
paper the interplay and subsequent optimization of caching based VNF service
chains. To this end, we detail a novel mathematical programming framework
tailored to VNF caching chains and detail also a scale-free heuristic 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 (UFL) problem. A wide set of numerical investigations are presented
for characterizing the attainable system performance of the proposed schemes.
