Reliable Network Services in Future Internet Service Provider Networks: Reliable and Efficient Control Plane Applications for Virtualized Data Planes in Software-Defined Networking

Driven by highly efficient over-the-top content providers, traffic on the Internet is increasing and puts pressure on Internet service providers (ISPs) to increase their efficiency as well. A promising approach to increase the efficiency of ISP networks is software-defined networking (SDN). SDN achieves this by separating the control from the data plane through a network protocol and thereby enabling increased automation and resource efficiency. However, today’s SDN-based control planes, consisting of control plane applications and an SDN controller to coordinate the data plane access, do not meet the reliability requirements for services in ISPs networks. With SDN, network services consist of multiple control plane applications combined in a single control plane. The control path in data plane elements is responsible for processing SDN protocol messages to configure the packet processing pipeline, termed data path. Today’s SDN controller designs do not virtualize the control path adequately, i.e., the effects of messages from different applications are not sufficiently isolated. Thereby, misbehaving low priority applications can block the control paths for essential high priority applications in ISP networks such as the network fabric. This lack of isolation can lead to control plane applications to fail unexpectedly and prevent the whole control plane from operating reliably. To this end, we introduce a novel, systematic resource-oriented approach to characterize the control paths in SDN data planes as well as a virtualization design for throughput aspects of control paths to increase the reliability among control plane applications. Based on these findings, we analyze the requirements of applications to operate on virtualized data planes. Local bottlenecks that only affect a single data plane element can be mitigated by shifting load to a different element. We apply this approach to our network function chaining design and investigate its effectiveness and provide insights on how the application should decide on the specifics of the mitigation process. Global control path bottlenecks affect a complete area of an ISP network. We analyze the interaction pattern that our novel Adaptive Software-Defined Multicast (ASDM) and Adaptive Bit-Index Software-Defined Multicast (ABSDM) designs require to identify such a bottleneck. Furthermore, we show how a global packet matching memory bottleneck can be mitigated by shifting the applications’ resource usage from matching memory to data rate. We demonstrate the effectiveness of the ASDM application for mitigating control path resource bottlenecks and thereby making it reliable. In this thesis, we close gaps in the virtualization of control paths that affect both SDN controllers and control plane applications. Thereby, we enable reliable SDN controllers and propose designs for reliable control plane applications to deliver SDN-based network services in ISP networks