SDN Heading North: Towards a Declarative Intent-based Northbound Interface

The Intent-Based Northbound Interface (NBI) offers users the ability to express what they want to achieve instead of how to achieve it, enabling improvements to network management and reducing operational costs. However, development of an Intent-Based NBI remains in its infancy. Existing solutions do not allow users to express high-level operational targets that appropriately capture business objectives, nor link these to lower-level management policies and operations. We propose an extensible Intent-based NBI framework and a higher-level declarative intent expression to enable service-oriented intents with different targets. We focus on the creation of intents and their mapping from high-level expressions to low-level policies, and consider this from the perspective of an intent developer in the context of a Cloud CDN use case.