Towards a Distributed SDN Control: Inter-Platform Signaling among Flow Processing Platforms

Today's Internet is a concatenation of IP networks interconnected by many distributed functions integrated into a plethora of highly specialized middleboxes. These elements implement complex network functions like firewalls, NATs, DPI, traffic scrubbing, etc. The product is a quite complex and rigid internetworking system in which network administrators and users cannot easily determine what is happening to traffic flows as they go toward destinations. SDN research and programmable network functions for flow processing and virtualization are unlocking the current scenario, though most of the COTS products generally support network functions only for virtual L2 switching over IP networks (e.g. VXLAN, GRENV, STT) and LAN based flow pinpointing. This paper presents a different perspective for implementing flow processing via distributed SDN controllers and inter-platform signaling. The distributed end-to-end service provisioning among adjacent flow processing platforms is implemented via a signaling framework in which the different actions/functions to be executed by each platform are described in a generic Flow Processing Route (FPR) object. The FPR is exchanged among the SDN controllers over the end-to-end network service path and contains information on routing rules and local flow processing actions to be instantiated at the different platforms. The proposed signaling architecture has been designed and implemented in the FP7-ICT CHANGE project. This paper reports on the key signaling architectural aspects and the developed signaling prototype.