Enabling SDN in Old School Networks with Software-Controlled Routing Protocols

Software-Defined Networking (SDN) promises to significantly improve network manageability by enabling direct, and centralized control over the network forwarding state via a well-defined Application Programming Interface (API). Fulfilling this promise though is a challenge for network operators as it often requires heavy modifications to their current network architecture, including: i) equipment upgrades, as the vast majority of the installed base of network equipments (e.g., routers) do not support SDN protocols; ii) new management, monitoring and provisioning systems; but also iii) the need for operators training as managing and debugging a SDN network requires essentially completely different skill sets.

In this short paper, we present a lightweight SDN solution that does not require any new network equipment, nor SDNspecific protocols. While it is less expressive than OpenFlow-based SDN, our solution is powerful enough to fulfill complex traffic engineering requirements (e.g., traffic steering through middleboxes, load-balancing) that are hardly achieved in traditional, configuration-based, networks. Moreover, by minimizing SDN inertial factors and simplifying the management interface exposed to network operators, our lightweight SDN model can provide significant incentives to bootstrap the transition towards SDN.