Towards Consistent Software Defined Networking with Logic Programming

• Main Authors: Lui, Chun-Quan, 呂峻權
• Other Authors: 吳育松
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/7p7jg5

碩士 === 國立交通大學 === 資訊科學與工程研究所 === 103 === Software Defined Networking (SDN) has been widely used in today’s cloud datacenter environment. In a cloud datacenter environment, tenants can specify a virtual network for their virtual machines. SDN technologies are employed to realize the virtual network on top of the datacenter network infrastructure. Due to unavoidable component failures, software bugs, and human errors, inconsistencies in the software defined network configuration are anticipated. The inconsistencies could result in network outage or violation of network security policy. In this paper, we propose a system that verifies the consistency of the configurations of a software defined network. The system employs a graph-based network model to describe the physical network topology and the logical network topology of a datacenter. Specifically, the network model covers the infrastructure description, the virtual network specification description, and the configuration state description. Logic constraints are generated from the network model and then fed to a constraint solver to verify the satisfiability of the constraints. If the constraints can be satisfied, the network configuration is consistent. Otherwise, the network configuration is inconsistent. We built a prototype system based on OpenStack and OpenFlow. The experiment results confirmed the system is able to detect various inconsistent configurations of a software defined network. The experiment results also indicate the system is efficient. It takes about 1 second to verify the consistency of a network with 6 virtual machines.