A southbound interface (SBI) connects an SDN controller’s Control Layer to network devices in the Infrastructure Layer. The controller translates high-level requirements into actionable instructions, which devices execute. section 22.2.2 section 22.4
Recognize these southbound protocols and their typical roles:
- OpenFlow lets a controller directly interact with and control a device’s data plane. section 22.2.2
- NETCONF is an IETF-defined, industry-standard protocol for modifying network-device configurations. section 22.2.2
- OpFlex is a Cisco-developed protocol used with Application-Centric Infrastructure (ACI). section 22.2.2
- SSH and SNMP can serve as traditional southbound management protocols. section 22.2.2
- Do not confuse the SBI with the northbound interface (NBI): the NBI connects applications to the controller and typically uses REST over HTTP. section 22.2.2
Figure 22.6 The three layers of SDN architecture: Application, Control, and Infrastructure. The NBI facilitates communication between the Application and Control Layers, and the SBI facilitates communications between the Control and Infrastructure Layers.
Use the SDN layer diagram to locate the SBI between the Control and Infrastructure Layers and distinguish it from the NBI. section 22.2.2
