Softflow: a middlebox architecture for open vSwitch

Open vSwitch is a high-performance multi-layer virtual switch that serves as a flexible foundation for building virtualized, stateless Layer 2 and 3 network services in multitenant datacenters. As workloads become more sophisticated, providing tenants with virtualized middlebox services is an increasingly important and recurring theme, yet it remains difficult to integrate these stateful services efficiently into Open vSwitch and its OpenFlow forwarding model: middleboxes perform complex operations that depend on internal state and inspection of packet payloads - functionality which is impossible to express in OpenFlow. In this paper, we present SoftFlow, an extension of Open vSwitch that seamlessly integrates middlebox functionality while maintaining the familiar OpenFlow forwarding model and performing significantly better than alternative techniques for middlebox integration.