What Does Northbound Interface Mean?
A northbound interface (NBI) is the interface to a component of higher function or level layer. The lower layer’s NBI links to the higher layer’s southbound interface (SBI).
In an architectural overview, a NBI is drawn on the top portion of the component or layer in question and can be thought of as flowing upward, while a SBI is drawn at the bottom, symbolizing a downward flow.
Techopedia Explains Northbound Interface
A NBI is an output-oriented interface that is usually found in carrier-grade networks and telecommunications network elements. An example of a NBI implementation is a device that only sends SYSLOG messages and cannot be manipulated to take any kind of input.
In addition, the language and protocols commonly used for these interfaces are Simple Network Management Protocol (SNMP) and Transaction Language 1 (TL1). The NBI complies with several standards within the ITU Telecommunication Standardization Sector (ITU-T) or TM Forum (TMF) series; these are used mostly for alarm, performance, inventory, provisioning, configuration and security related information of the network elements that are passed or forwarded to a higher level management system known as Operational Support System (OSS).
Northbound integration is usually implemented through the following interfaces:
Extensible Markup Language (XML)
File Transfer Protocol (FTP)
SNMP, System Log (SYSLOG). Terminal Access Controller Access Control System (TACACS) and Lightweight Directory Access Protocol (LDAP)