Network Function Placement for NFV Chaining in Packet/Optical Datacenters

TLDR

Optical technologies enable NF chaining for aggregated flows, while NFV allows on‑demand placement of virtualized NFs in datacenters. The study aims to minimize costly optical/electronic/optical conversions caused by on‑demand vNF placement in packet/optical datacenters. By grouping vNFs of a chain into fewer pods, the authors formulate optimal placement as a binary integer program and propose an efficient heuristic to reduce unnecessary optical traversals. The heuristic achieves near‑optimal O/E/O conversions comparable to the BIP solution and outperforms a simple first‑fit algorithm across various scenarios.

Abstract

In an operator's datacenter, optical technologies can be employed to perform network function (NF) chaining for larger aggregated flows in parallel with the conventional packet-based fine-grained traffic steering schemes. When network function virtualization (NFV) is enabled, virtualized NFs (vNF) can be placed when and where needed. In this study, we identify the possibility of minimizing the expensive optical/electronic/optical (O/E/O) conversions for NFV chaining in packet/optical datacenters, which is introduced by the on-demand placement of vNFs. When the vNFs of the same NF chain are properly grouped into fewer pods, traffic flows can avoid unnecessary traversals in the optical domain. We formulate the problem of optimal vNF placement in binary integer programming (BIP), and propose an alternative efficient heuristic algorithm to solve this problem. Evaluation results show that our algorithm can achieve near-optimal O/E/O conversions comparable to BIP. We also demonstrate the effectiveness of our algorithm under various scenarios, with comparison to a simple first-fit algorithm.