Critical groundwork on the interfaces between software-defined networking (SDN) controllers and the application layer has been undertaken by the Open Networking Foundation 's (ONF) recently-formed Northbound Interfaces Working Group, laying the path for a greater understanding of how SDN can be utilized in multiple data-networking scenarios.

ONF is working on multiple fronts to develop SDN architectures for enterprises and network operators and to promote the use of the OpenFlow protocol in next generation networks. It stated in an email update this week that the working group, announced only a few months ago, has already identified a number of use cases and "levels of abstraction." ONF plans to share these when it publishes its Northbound Interface "information models" later this year. Those models, it says, will be "accompanied by open-source working code for select use cases." (See HP Exec Goes Northbound for SDN.)

The so-called Northbound Interface is important because it is the application programming interface (API) between SDN controllers and applications, management systems, and orchestration software. (The Southbound Interface, meanwhile, is the API that enables a controller to define the behavior of switches/routers, with OpenFlow being a prime example of a Southbound Interface protocol.)

Many different Northbound APIs already exist. ONF is providing guidance on what those APIs are and on the instances in which they are most applicable. It is not, ONF's executive director Dan Pitt explained in a November article written for Light Reading, developing a standard Northbound API. It is however monitoring the potential use of certain specifications that could be of use to network operators, vendors, and developers. (See Compass Check: ONF & the Northbound API(s).)

Identifying and evaluating Northbound APIs is just one of a number of current major challenges for the SDN community. Others revolve around the issues of OSS and orchestration. (Expect the Service Provider Information Technology (SPIT) community to be very active in this area during 2014.) Another area of focus is security, where SDN developers are working towards self-defending systems, such as SE-Floodlight, that use analytics to identify potential threats and adjust data flows.

With 2014 set to be another major year for networking professionals considering SDN's potential, developments such as the Northbound Interface APIs and network security models are important, especially considering that they are progressing at a pace not often seen in the telco world. That's particularly important because, while SDN was borne of the datacenter sector initially, Pitt believes that telecom service providers will be the key drivers behind SDN and network functions virtualization (NFV) developments this year. (See AT&T Revamps Supplier Program for SDN/NFV and Top 5 NFV Movers & Shakers.)

— Ray Le Maistre, Editor-in-Chief, Light Reading