Software-Defined Label Switching: Scalable Per-Flow Control in SDN

Deploying Software-Defined Networks (SDNs) faces various challenges, and one of them is to implement per-flow control while preserving data plane scalability. Due to the limited rule storage space of commodity SDN switches, achieving flexible control and having a low-latency data plane with a low storage cost are often at odds. Unfortunately, existing SDN architectures fail to implement per-flow control efficiently: they either incur extra delays to packets or pose high storage burden to switches. In this paper, we propose Software-Defined Label Switching (SDLS) to achieve both data plane scalability and per-flow control. SDLS combines central control with label switching to reduce storage burden while maintaining per-flow control. SDLS introduces software switches into the data plane and manages the network in regions for scalability. SDLS is OpenFlow-compatible and employs a hybrid data plane to provide efficient flow setups. We evaluate SDLS by comparing with the state-of-the-art SDN architectures and show that SDLS can rival the best on the latency performance while reducing the number of flow entries and overflows by more than 47%.