What is Southbound Interface (SBI)?
A southbound interface (SBI) is the interface level of a component. It is directly connected to the northbound interface of this lower layer. It breaks down the concepts into smaller technical details that are specifically geared towards a lower layer component within the architecture.
In software-defined networks (SDN), the southbound interface serves as an OpenFlow or alternative protocol specification. It enables a network component to communicate with a lower level component.
The main goal of a southbound interface is to provide communication and management between the network's SDN controller, the nodes, the physical / virtual switches and the routers. It enables the router to discover the network topology, define the network flow, and implement multiple requests forwarded by northbound application programming interfaces (API).
The network nodes are managed via the network management system (NMS) approved 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)
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