Performance and Reliability in Open Router Platforms for Software-Defined Networking

The unprecedented growth of the Internet has brought about such an enormous impact on our daily life that it is regarded as indispensable in modern era. At the same time, the underlying Internet architecture is still underpinned by principles designed several decades ago. Although IP networking has been proven very successful, it has been considered as the cause to network ossification creating barriers to entry for new network innovations. To support new demands and requirements of the current and the future Internet, solutions for new and improved Internet architectures should be sought. Software-defined networking (SDN), a new modularized network architecture that separates the control plane from the data plane, has emerged as a promising candidate for the future Internet. SDN can be described as flow-based networking, which provides finer granularity while maintaining backward compatibility with traditional IP networking. In this work, our goal is to investigate how to incorporate flow-based networking into open router platforms in an SDN context. We investigate performance and reliability aspects related to SDN data plane operation in software on open source PC-based routers. Our research methodology is based on design, implementation, and experimental evaluation. The experimental platform consists of PC-based routers running open source software in combination with commodity-off-the-shelf (COTS) hardware components. When it comes to performance aspects, we demonstrate that by offloading the lookup from a CPU to a network interface card, the overall performance is improved significantly. For enhanced reliability, we investigate bidirectional forwarding detection (BFD) as a component to realize redundancy with fast failover. We demonstrate that BFD becomes unreliable under high traffic load and propose a solution to this problem by allocating dedicated system resources for BFD control messages. In line with this solution, we extend our architecture for next-generation PC-based routers with OpenFlow support by devising a strategy to efficiently map packet forwarding and application processing tasks onto the multi-core architecture on the PC-based router. This extension would make it possible to integrate BFD effectively into the router platform. Our work demonstrates the potentials of open router platforms for SDN. Our prototypes offer not only high performance with good reliability but also flexibility to adopt new software extensions. Such platforms will play a vital role in advancing towards the future Internet.