Stringer: Balancing Latency and Resource Usage in Service Function Chain Provisioning

Network function virtualization (NFV) enables telecommunications infrastructure providers to replace special-purpose networking equipment with commodity servers running virtualized network functions (VNFs). A provider using NFV faces the service function chain (SFC) provisioning problem of assigning VNF instances to nodes in the physical infrastructure (for example, datacenters), and routing SFCs (which are sequences of functions required by customers) in the physical network. The provider must balance competing goals of performance and resource usage. This article presents an approach to SFC provisioning, consisting of three elements. The first element is a fast and scalable round-robin heuristic. The second element is a mixed integer programming-based approach. The third element is a queueing-theoretic model to estimate the average latency associated with any SFC provisioning solution. This SFC provisioning system, called Stringer, allows providers to balance the conflicting goals of minimizing infrastructure resources and end-to-end latency for meeting their respective service-level agreements.