Light Reading
Why it's time to bring clarity to the SDN controller northbound interface debate.

Compass Check: ONF & the Northbound API(s)

Dan Pitt
Column
Dan Pitt
11/6/2013
50%
50%

The Open Networking Foundation (ONF) turned a lot of heads in October with the announcement of a Northbound Interfaces (NBI) Working Group.

While we're always glad to draw more attention to the benefits of Software-Defined Networking (SDN), we want to be sure that the industry truly understands why we are looking north and how this new Working Group fits into the overall focus of Open Networking Foundation (ONF). This is especially important since we have been so vocal for more than two years about why we are not standardizing the northbound API. (Believe me, I've taken a lot of flak for that, but steadfastly resisted.)

ONF's mission is to accelerate the adoption of open SDN. To us, SDN includes both the OpenFlow substrate and the enablement of applications and services above it. This means that while our NBI Working Group is new, our work with the Northbound Interface is not.

Back in June 2011, we received an inquiry from another industry group asking if we planned to standardize the Northbound API. "Goodness, no," we replied, but we neglected to say why.

"Oh good," they replied. "Then we will."

Damage control included explaining why no one should, because:

  • No one had enough experience with OpenFlow controllers to know what to standardize
  • This period of innovative experimentation was important for learning and we did not want to stifle it
  • Anyone who tried would surely get it wrong
  • There won't be just one NBI anyway, and
  • That's not how software artifacts get standardized.

Fortunately, they listened.

Since then, the industry has built a considerable body of experience. With a solid OpenFlow substrate, the attention now shifts to include the software and services that the foundation enables. We have seen a greater demand from developers of application, orchestration, and management software for assistance in understanding NBIs as a critical component of a complete SDN solution.

So in the fall of 2012 we began looking at NBIs in the form of the Architecture and Framework Working Group's study of existing SDN use cases and controller interfaces, which are many. The large number of unique controller APIs indicates that there is no consensus yet on what makes the right NBI (and could also lead one to believe that they are not that hard to write). We will soon publish the first edition of our NBI study, cataloguing and comparing them.

While this proliferation of SDN controllers brings some valuable learning, it also creates confusion for those wanting to write to an NBI. Without stable interfaces to write to, overall adoption of SDN slows, and when we heard concerns from many in the ONF user population, we knew that we had to take action.

The question then became: What action should the ONF take? We have long said that software APIs are not typically standardized in advance by committees, because they don't have to be. Anyone can modify an (open) interface quickly; it's not like redesigning an ASIC. What we as an organization can do is bring clarity to the choices and their benefits, through both investigation and prototyping.

Therefore, ONF took the leap and chartered the NBI Working Group, which is evaluating Northbound Interfaces. Plural. That's an important distinction. The Working Group has already put together a chart showing how broad the topic is. Characterizing the different levels of abstraction as latitudes and the different use cases as longitudes, they starkly demonstrate the futility of imagining there being one, or "the," NBI.

Our first step will be to develop information models for Northbound Interfaces at different latitudes and longitudes with plans to prototype and gain market feedback on select examples. Again, examples -- plural.

What we don't plan to do is rush to a standard. ONF has spoken passionately about standards, and we have committed to standardizing only what is truly necessary. If the industry needs us to help them arrive at a standard for some use case, we will. Prominent among our members' requirements are for the interfaces they write to to be truly open and not vulnerable to the whims of a single vendor. Moreover, we suspect that a small number of NBIs will serve a large fraction of current market needs. Thus, one of the purposes of our NBI Working Group will be to determine if an NBI standard from a committee is needed by the market at this time.

ONF plans to publish its Northbound Interface information models in 2014, accompanied by open-source working code for select use cases. We will also continue to strengthen the OpenFlow substrate to make sure it offers great service to the software and services above the NBI.

As always, user needs remain our only compass.

— Dan Pitt, Executive Director, Open Networking Foundation

(1)  | 
Comment  | 
Print  | 
Newest First  |  Oldest First  |  Threaded View
sam masud
50%
50%
sam masud,
User Rank: Light Sabre
11/6/2013 | 2:33:21 PM
So what now?.
Dan,

Although it makes a lot of sense to have standard NBIs, I'm wondering whether having ONF standardize on the NBIs might slow the down the adoption of SDN. Also, curious as to what you would advise a customer who's considering deploying SDN--should they wait on the ONF's NBIs or go with whatever solutions are out there?

 
More Blogs from Column
Communications service providers need to become digital service providers, but what exactly does that entail?
Here are some ideas for how cable operators can help low-income households connect to pay-TV and broadband services.
Once SDN and NFV are added to already complex wide area networks, management and security become even greater challenges for operators.
Operators should leverage their network, QoS, billing and big data to compete against OTT players with both consumer and enterprise offers.
Is it smarter to centralize network intelligence for LTE-Advanced and 5G, or continue the Flat-IP 4G trend of pushing intelligence to the edge?
Flash Poll
From The Founder
Is your network built on 'The Old IP,' or are you part of 'The New IP' revolution?
LRTV Huawei Video Resource Center
Innovating Access Technology With G.fast

10|1|14   |   3.42   |   (0) comments


Exploring the potential of G.fast technology from the point of view of the Broadband Forum, Huawei – and an end-user.
LRTV Documentaries
A Cultural Shift for an OTT World

9|26|14   |   01:41   |   (3) comments


Telcos need to embrace a new approach to partnerships if they are to generate extra revenues quickly and give customers what they want.
LRTV Documentaries
New Skills Needed as Telecom, IT Collide

9|26|14   |   4:07   |   (1) comment


As telecom and IT collide, new technologies are emerging, new skills are needed and new opportunities for women are arising.
UBB Forum News
Do IP Networks Need An Overhaul?

9|25|14   |   02:01   |   (0) comments


As traffic levels ramp, do IP networks need new technologies and topologies?
LRTV Documentaries
Sprint Wields Its Influence in the Valley

9|25|14   |   3:09   |   (11) comments


Anne-Louise Kardas, Sprint's connection to startups in the Valley, explains how telcos can be innovative and find new opportunities with partners.
LRTV Documentaries
SDN, NFV & The Future of XO's Network

9|25|14   |   3:47   |   (1) comment


XO Communications COO Don MacNeil explains how cloud, SDN and NFV are altering its network requirements as well as changing data centers of the future.
UBB Forum News
The OTT Conundrum

9|24|14   |   01:39   |   (0) comments


What is holding back prosperous partnerships between telcos and the OTT players?
LRTV Documentaries
Putting Broadband to Work

9|24|14   |   01:26   |   (0) comments


High-speed broadband network rollout is key to telco strategies, but it's what happens after the network is built that counts.
Light Reedy
Light Reading's Women in Telecom Recap

9|24|14   |   0:55   |   (4) comments


Our first Women in Telecom breakfast was a huge success, and we hope you'll join us in London for the next event on November 6.
UBB Forum News
Monetizing Ultra-Broadband

9|24|14   |   01:43   |   (2) comments


Ultra-broadband networks need to be built, with fiber-to-the-premises the ultimate goal, but they need to be monetized, too.
LRTV Huawei Video Resource Center
Sales Director of INIT on Plug & Play Switch Devices

9|19|14   |   3:21   |   (0) comments


INIT Italy uses both the Huawei S5700 and S7700 series switches for the campus LAN environment. Sales Director Andrea Curti says their company chose these Huawei devices over others because of their performance, flexible scalability and plug-and-play features.
LRTV Huawei Video Resource Center
Saudi Arabia Upgrades Vocational Training System

9|19|14   |   3:31   |   (0) comments


The Technical and Vocational Training Corporation (TVTC) has 100,000 students, 150 government-owned institutions and oversees 1000 private institutes. The CIO of TVTC explains that Huawei devices have allowed them to manage multiple datacenters using just one software program, scientifically tracking the progress of students and teachers, saving them millions.
Upcoming Live Events
October 29, 2014, New York City
November 6, 2014, Santa Clara
November 11, 2014, Atlanta, GA
December 2, 2014, New York City
December 3, 2014, New York City
December 9-10, 2014, Reykjavik, Iceland
June 9-10, 2015, Chicago, IL
Infographics
Half of the world's population will be connected to the Internet by 2017, but not just by smartphones and desktops.
Hot Topics
Facebook Pokes Around LTE Direct
Sarah Reedy, Senior Editor, 9/25/2014
Is Redbox Instant Shutting Down?
Mari Silbey, Independent Technology Editor, 9/30/2014
Sprint Wields Its Influence in the Valley
Sarah Reedy, Senior Editor, 9/25/2014
US Ignite Cultivates Gigabit Apps
Jason Meyers, Senior Editor, Utility Communications/IoT, 9/25/2014
Comcast Turns Off Streampix
Mari Silbey, Independent Technology Editor, 9/26/2014
Like Us on Facebook
Twitter Feed