A 400 Gb/s Carrier-Class SDN White-Box Design and Demonstration: The Bitstream Approach

Software defined networks (SDNs) could be a game changer for next generation provider networks. OpenFlow (OF)-the dominant SDN protocol, is rigid in its south bound interface-any new protocol field that the hardware must support, must await complete OF standardization. In contrast, OF alternatives such as protocol oblivious forwarding and forwarding and control element separation have simpler schemes for insertion of new protocol identifiers. Even with these there is an inherent limitation on network hardware-the tables must support specific formats and configuration at each node as per protocol semantics. We ask the question-can we design an open system (white-box) - one that is carrier-class, yet able to meet the requirements of any protocol forwarding/action with a minimal set of data-plane functions. We propose bitstream, a low-latency, source-routing based scheme that can support addition of new protocols, be compatible with existing protocols, and facilitate a minimum semantic set for acting on a packet. A prototype is built to show bitstream working. The controller architecture is detailed from a provider perspective, as to how it can be integrated in a provider network using YANG models. The hardware architecture is also presented, showing the functioning of a bitstream capable 400 Gb/s whitebox. The issue of protocol processing optimization is considered and its impact on service latency is shown. The results from the test-bed validate the carrier-class features of the bitstream model.