Southbound Interface

Why Trust Techopedia

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)


Related Terms

Margaret Rouse
Senior Editor
Margaret Rouse
Senior Editor

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.