  Service function chaining (SFC) is promising to implement flexible and
scalable virtual network infrastructure for the Internet of Things (IoT). Edge
computing is envisioned to be an effective solution to process huge amount of
IoT application data. In order to uniformly provide services to IoT
applications among the distributed edge computing nodes (ECNs), we present a
unified SFC orchestration framework based on the coordination of SDN and NFV,
which provides a synergic edge cloud platform by exploiting the connectivity of
FiWi access networks. In addition, we study the VNF deployment problem under
our synergic framework, and we formulate it as a mixed-integer nonlinear
programming (MINLP) problem jointly considering the load balancing of
networking and computing for chaining VNFs. We also propose two approximation
optimal deployment algorithms named Greedy-Bisection Multi-Path (GBMP) and KSP
MultiPath (KSMP) taking advantage of the multi-instance virtual network
functions (VNFs) deployed in ECNs and the multipath capacity in FiWi access
networks. Extensive simulations are conducted in two types of IoT application
scenarios in the EC over FiWi access networks. The numerical results show that
our proposed algorithms are superior to single path and ECMP based deployment
algorithms in terms of load balancing, service acceptance ratio, and network
utilization in both two typical scenarios.
