Hierarchy Descending SFC Provisioning Scheme With Load Balancing in Fog Computing

This letter presents a novel provisioning scheme for service function chain (SFC) requests for delay-sensitive applications. The SFC is comprised of virtual network functions (VNF) to be mapped on a multi-tier fog architecture composed of primary and secondary nodes with limited resources. Now existing provisioning methods establish service paths based on least delay or load, and then map single VNFs on each fog node. However, these approaches can yield early congestion at the primary nodes, thus leaving secondary nodes unoccupied due longer link delays. To solve this problem, the proposed scheme leverages a descending hierarchical approach to enhance admission and utilization rates and reduce provisioning delays. At low traffic volumes, it performs grouped VNF mapping on secondary nodes through shorter paths that skip underloaded primary nodes. At high traffic volumes, it performs single mapping on primary nodes over established paths.