Fastlane-ing more flows with less bandwidth for software-Defined networking

Software-Defined Networking (SDN) has greatly boosted the productivity of data center networking and cloud computing. It introduces a central controller to take over most functions that otherwise reside in distributed forwarding devices. Such a centralized design, however, tends to make the control channel a bottleneck due to bandwidth fatigue. Only when this bottleneck is addressed can SDN greater benefit networking and computing infrastructures. Existing work saves control channel bandwidth at the expense of losing flow visibility. This paper designs and implements FastLane, a framework for bandwidth-efficient yet throughput-boosting SDN flow setup without sacrificing global flow visibility. FastLane informs only one on-path switch of a flow's forwarding path while switches themselves cooperate to complete flow setup. FastLane thus keeps minimum traffic for flow setup in the control channel and leaves the rest to the data plane. We optimize the switch selection toward minimizing flow setup latency. To leverage the saved bandwidth for setting up more flows and therefore achieving higher throughput, we propose delegating certain flow setups from ingress to en-route switches. We prototype FastLane by modifying FloodLight controller and Open vSwitch. The results demonstrate FastLane's benefits to higher SDN throughput with limited switching fabric overhead.