East/Westbound Interfaces and Hierarchical Controller Designs

Investigate and define east/westbound interfaces among software-defined networking controllers, including their role in enabling hierarchical controller designs that achieve scalability, modularity, and security across distributed and multi-domain environments.

Background

The paper discusses modularity and flexible composition of controller platforms and notes gaps in how controllers interact horizontally (east/westbound) in distributed settings. Such interfaces are critical for data sharing, consistency models, and coordination across controller instances and domains.

The authors explicitly identify the need to further study east/westbound interfaces, particularly for hierarchical designs intended to scale and segment functionality and trust domains, making this a concrete open area of SDN controller research and standardization.