On the Safety and Efficiency of Virtual Firewall Elasticity Control

Traditional hardware-based firewall appliances are placed at fixed locations with fixed capacity. Such nature makes them difficult to protect today's prevailing virtualized environments. Two emerging networking paradigms, Network Function Virtualization (NFV) and Software-Defined Networking (SDN), offer the potential to address these limitations. NFV envisions to implement firewall function as software instance (a.k.a virtual firewall). Virtual firewalls provide great flexibility and elasticity, which are necessary to protect virtualized environments. In this paper, we propose to build an innovative virtual firewall controller, VFW Controller, to enable safe, efficient and costeffective virtual firewall elasticity control. VFW Controller addresses four key challenges with respect to semantic consistency, correct flow update, buffer overflow avoidance, and optimal scaling in virtual firewall scaling. To demonstrate the feasibility of our approach, we implement the core components of VFW Controller on top of NFV and SDN environments. Our experimental results demonstrate that VFW Controller is efficient to provide safe elasticity control of virtual firewalls. Permission to freely reproduce all or part of this paper for noncommercial purposes is granted provided that copies bear this notice and the full citation on the first page. Reproduction for commercial purposes is strictly prohibited without the prior written consent of the Internet Society, the first-named author (for reproduction of an entire paper only), and the author's employer if the paper was prepared within the scope of employment.