What Does Southbound Interface Mean?
A southbound interface (SBI) is a component’s lower level interface layer. It is directly connected to that lower layer’s northbound interface. It breaks down the concepts into smaller technical details that are specifically geared toward a lower layer component within the architecture.
In software-defined networking (SDN), the southbound interface serves as the OpenFlow or alternative protocol specification. It allows a network component to communicate with a lower level component.
Techopedia Explains Southbound Interface
The main objective of a southbound interface is to provide communication and management between the network’s SDN controller, nodes, physical/virtual switches and routers. It allows the router to discover the network topology, define network flow and implement several requests relayed from northbound application programming interfaces (API).
The management of network nodes is handled by the Network Management System (NMS) allowed by the southbound interface. The southbound integration is supported by the following interfaces:
Simple Network Management Protocol (SNMP)
Command Line Interface (CLI)
File Transfer Protocol (FTP) or SSH File Transfer Protocol (SFTP)
Telnet (TN) or Secure Shell (SSH)