Common Northbound Interface for SDN Controllers

Develop a common, standardized northbound application programming interface for software-defined networking controllers that enables application portability and interoperability across control platforms while abstracting device-specific and southbound API details.

Background

The survey contrasts the maturity of southbound interfaces—most notably OpenFlow—with the lack of a corresponding common northbound interface. The authors emphasize that while OpenFlow provides a widely accepted mechanism to program forwarding devices, application developers still face fragmentation across controllers due to differing northbound APIs.

A standardized northbound interface would serve as a portability and interoperability layer for SDN applications, analogous to POSIX in operating systems, allowing developers to write controller-agnostic applications and simplifying adoption across heterogeneous control platforms.