NoBI: uma interface Northbound para a programação dinâmica de redes OpenFlow com suporte à interoperabilidade entre controladores.

Abstract

The Software-Defined Networking (SDN) is a new paradigm that is attracting significant interest from both academy and network industry. Unlike tradicional networks, the SDN paradigm enables innovation by encouraging the separation of network’s control logic from the underlying devices and introducing the ability to orchestrate the network in a high-level fashion. In recent years, increasing research efforts have addressed the conception of northbound programming interfaces (NBIs), which allow business-applications and network administrators to properly communicate with SDN controllers and program the network. However, albeit the current consolidation of the OpenFlow, the lack of a standard for the NBI makes it very difficult for administrators to create interoperable code. Currently, dozens of SDN controllers are available, but each one is free to design and implement its own NBI. So as the number of controllers have increased dramatically, the ability of network managers to use NBI functions have become such a problematic and sometimes an impossible task, given the differences in programming languages and instructions among SDN controllers. As a result, the lack of a interoperable NBI implementation often forces administrators to manually rewrite almost all of their code, every time they need to support a new controller. Also, migrating existing network instruction sets to another controller is a tedious and time-consuming process that typically involves learning new APIs, complex data models and various controller-dependent conventions. To address this limitation, we present an alternative northbound API, called NoBI, that allows administrators to easily program the SDN irrespective of the existing controller. Particularly, NoBI provides a REST-based set of functions that is truly interoperable, and thus may communicate seamlessly with more than one controller. In order to meet multi-controller interoperability requirement, we introduce an new architecture that can be easily instantiated and also new data models compatible with two prominent SDN controllers (Floodlight and OpenDaylight). So rather than injecting intricate low-level instructions directly into the code to program the SDN, administrators will interact only with NoBI. It translates automatically all the high-level requests into internal NBI calls and native data models supported by the underlying controller. We demonstrated the feasibility of our solution in real single-controlled SDN architectures using different OpenFlow devices. Our results show that our solution is able to program the SDN at runtime and yet fulfill the interoperability requirement, while statistically achieving similar operational results compared to state-of-the-art baselines.