Orchestrating Virtualized Network Functions

Abstract: Middleboxes or network appliances like firewalls, proxies, and WAN optimizers have become an integral part of today’s ISP and enterprise networks Middlebox functionalities are usually deployed on expensive and proprietary hardware that require trained personnel for deployment and maintenance Middleboxes contribute significantly to a network’s capital and operation costs In addition, organizations often require their traffic to pass through a specific sequence of middleboxes for compliance with security and performance policies This makes the middlebox deployment and maintenance tasks even more complicated Network function virtualization (NFV) is an emerging and promising technology that is envisioned to overcome these challenges It proposes to move packet processing from dedicated hardware middleboxes to software running on commodity servers In NFV terminology, software middleboxes are referred to as virtualized network functions (VNFs) It is a challenging problem to determine the required number and placement of VNFs that optimizes network operational costs and utilization, without violating service level agreements We call this the VNF orchestration problem (VNF-OP) and provide an integer linear programming formulation with implementation in CPLEX We also provide a dynamic programming-based heuristic to solve larger instances of VNF-OP Trace driven simulations on real-world network topologies demonstrate that the heuristic can provide solutions that are within 13 times of the optimal solution Our experiments suggest that a VNF-based approach can provide more than $ {4\times }$ reduction in the operational cost of a network