Enabling Novel Interactions between Applications and Software-Defined Networks

Over the last few decades the pervasive diffusion of software has greatly simplified the introduction of new functionalities: updates that used to require complex and expensive re-engineering of physical devices can now be accomplished almost at the push of a button. In the context of telecommunications networks, recently modernized by the emergence of the Software-Defined Networking (SDN) paradigm, software has manifested in the form of self-contained applications driving the behavior of the control plane of the network. Such SDN controller applications can introduce profound changes and novel functionalities to large deployed networks without requiring downtime or any changes to deployed boxes, a revolutionary approach compared to current best practices, and which greatly simplifies, perhaps even enables, solving the challenges in the provisioning of network resources imposed by modern distributed business applications consuming a network’s services (e.g., bank communication systems, smart cities, remote surgery, etc.). This thesis studies three types of interaction between business applications, SDN controller applications and networks with the aim of optimizing the network response to a consumer’s needs. First, a novel interaction paradigm between SDN controller applications and networks is proposed in order to solve a potential configuration problem of SDN networks, which is caused by the limited memory capacity of SDN devices. An algorithm that offers a virtual memory to the network devices is designed and implemented in a SDN application. This interaction shows an increase of the amount of traffic that a SDN device can process in the case of memory overflows. Second, an interaction between business applications and SDN networks shows how it is possible to reduce the blocking probability of service requests in application-centric networks. A negotiation scheme based on an Intent paradigm is presented. Business applications can request connectivity service, receive several alternative solutions from the network based on a degradation of requirements and provide a feedback. Last, an interaction between business applications, SDN controller applications and networks is defined in order to increase the number of ad-hoc connectivity services offered by network operators to customers. Several service providers can implement a connectivity service in the form of SDN applications and offer them via a SDN App Store on top of a SDN network controller. The App Store demonstrates a lower overhead for the introduction of customized connectivity services.