• 04/28/2014
    12:00 PM
    Ethan Banks
  • Ethan Banks
  • Commentary
  • Connect Directly
  • Rating: 
    0 votes
    Vote up!
    Vote down!

50 Shades Of Open SDN

The word open is used frequently in the software-defined networking market, but a closer look at three SDN initiatives shows that the meaning of open depends on your point of view.

In the competitive landscape of software-defined networking, vendors often use the word "open." Either a vendor claims its product is open, or a competitor counters that it's not. This really raises a question: What does it mean to be open? As with so many issues in networking, the answer to that question is "It depends." The best way to address this conundrum is to look at what certain vendors and projects mean when they say open. I think we'll find that the notion of open has become fluid.

Cisco ACI
Cisco's Application Centric Infrastructure is Cisco's holistic SDN initiative consisting of a controller called APIC, compatible hardware, and the newly introduced OpFlex protocol. On Cisco's ACI landing page, the company describes ACI as "an open ecosystem" that provides "support for open networking," with a key characteristic: "open software flexibility for DevOps teams and ecosystem partner integration."

That's a heavy use of the word open -- a theme that continues as you read through Cisco ACI literature. So what does this really mean? Can you download APIC and use it freely? No. Can you dig into the source code and modify it as you see fit, launching your own APIC fork on GitHub? Again, no.

What it does mean is that you can integrate your product or process with the APIC controller using a variety of APIs that Cisco provides. In that sense, there is a degree of openness. The door has been opened to allow Cisco infrastructure to be integrated with other vendor infrastructure and customer operations via a programmatic interface.

That said, this is not the same sort of open that network practitioners have come to expect. While Cisco will open the door to anyone who wants to integrate with its infrastructure -- a savvy, if obvious, business decision -- Cisco is not giving intellectual property away to anyone who might like to use it. Cisco ACI, OpFlex, and related APIs are open in the sense that Cisco is offering a key to drive its car around. It is not opening the hood and allowing engine modifications.

The Open Networking Foundation is the organization behind the protocol OpenFlow. With such prominent use of the word open, OpenFlow must be open, correct? Well, yes -- and no. Participation in OpenFlow's development is only available to ONF members. Membership in the ONF costs $30,000 annually. Startups catch a break, paying only $1,000 annually for their first two years.

A select number of academicians can participate freely. Even ONF working group and discussion group mailing lists are shrouded from the public, as only ONF member email domains are permitted to join.

So the process of developing OpenFlow is not open to the general public. What about the products the ONF creates, i.e. OpenFlow? Surely, those who wish to bake the OpenFlow specification into their products can do so. Again, yes and no.

The ONF's OpenFlow trademark policy requires contacting the ONF for a written license agreement unless your usage falls into an exception category. One of those exceptions is for community-developed implementations of OpenFlow "released free of charge and under an Open Source Initiative-approved license." The trademark policy makes it seem like perhaps anyone could use OpenFlow for noncommercial purposes, but the story becomes more complex when reviewing the ONF Intellectual Property Rights document.

This document states: "Each Member, on behalf of itself and its Affiliates, hereby grants to the other Members and their Affiliates... worldwide license under their Necessary Claims to make, have made, use, import, offer to sell, lease, sell and otherwise distribute Compliant Portions."

Hmm. In other words, ONF members allow all other ONF members to use OpenFlow "compliant portions" however they like, with some caveats further detailed in the policy. Perhaps I missed it in the jargon-laden document, but I saw no provision allowing ONF nonmembers to create OpenFlow products.

How, then, is OpenFlow open? In the sense that a large number of organizations with an emphasis on end users are working together as members to create a protocol, OpenFlow is open -- a point not to be understated. I believe most of the networking industry feels that OpenFlow is an open standard. However, the ONF's process is closed to public viewing, participation, and productization, making OpenFlow somewhat less open than its name implies.

In contrast to Cisco ACI's and ONF's flavors of "open," the OpenDaylight (ODL) SDN initiative is a completely open project. Membership in ODL is not exclusive. Anyone can participate and commit code, assuming the code has merit as determined by the community. In fact, OpenDaylight is actively seeking contributors.

The ODL process is open; anyone can subscribe to the mailing lists of the various projects or the technical steering committee, and anyone can participate in the public IRC channels. The ODL products are consumable by anyone. Whoever would like to work with OpenDaylight's first release, Hydrogen, can freely download the product. OpenDaylight could even be used as a baseline for other products that are later commercialized. Simply stated, OpenDaylight is as open as open gets.

Open to interpretation
Clearly, open means different things in networking literature; context is extremely important. All of the technology I mentioned here is indeed open... from a certain point of view. IT practitioners need to understand the context and point of view clearly to know what is meant when the word "open" is used. Armed with that knowledge, they can then decide which open basket to place their eggs into.


Game of Semantics

This is a good breakdown, Ethan. Thanks to the open source movement, the term "open" has, in my opinion, a positive connotation. It's clear that companies like Cisco hope some of those good vibes might rub off by calling their systems "open" when what they really mean is "you can integrate with it." I don't think any potential customer is fooled by a vendor's twisting of the word "open," but I guess marketing depts. can't help themselves.

OpenDaylight does seem like the most traditionally "open" of the three you mention, but I think you have to pony up some serious money to be part of the Technical Steering Committee.

Re: Game of Semantics
Drew, I think that "you can integrate with it" is a very good description of what most vendors mean when they use the term open these days (or perhaps "you can hire us to integrate with it"). "Open" certainly does not equate to "open-source" which is how customers tend to interpret it. I think the positive association is starting to wear off, however, because overuse is making users suspicious of the term. Kind of like, oh, maybe "software-defined"?
Re: Game of Semantics

I agree people are demanding openness in the solutions, but is it only about overcoming challenges like vendor lock-in, requirement change, end of life or anything else because migration cost attached with the SDN seems little high.

Re: Game of Semantics

Aditshar1, yes, and does that seem like a lot to ask? I doesn't to me. Customers want general interoperability between products, which should be the normal state of things. Unfortunately the networking industry has evolved differently. Now customers are taking things to a whole new level because they are tired of vendor control.

Re: Game of Semantics

What i believe is that it often requires proprietary customization for implementation or modification that varies by network provider, which further seems concern if your network is under or taken care by some 3rd party.

Excellent topic to expose
I am very glad Ethan has raised this issue, even if I don't completely agree with his conclusions. He is getting at the heart of how loosely the term "open" is thrown around. As the Executive Director of the Open Networking Foundation, I understand and wholeheartedly value openness in SDN. The organization takes this very seriously, and this is why our mission is to accelerate the adoption of open SDN for the benefit of the network operator and end user. We did not start out calling it "open SDN", just SDN, but we have found it important to do so because of how loosely "open" is used (and misused). Open Networking has taken on a hugely new and valuable meaning with SDN, and our Foundation is structured deliberately to bring this about, with the users in an unusually prominent role. Our activities and policies are heavily weighted to benefit (as with governance) and protect (as with trademarks) the user, especially given how disruptive SDN can be to the status quo. By the way, OpenFlow is available for anyone to use. Our IPR policy means only that members do not need to negotiate licenses with each other for any IP contributed to the specifications. This eliminates all the legal wrangling that goes on in most SDOs (often behind the scenes), and results in no difference at all to non-participants.
Note that we define open technologies as those that are not only published and available to all but also are not overly controlled by a single party. So with any "open" activity or organization, it is important to know who wields the influence and how decisions are made. Since ONF's success measure is the commercial success of SDN, we need suppliers and consumers of the technology to agree on what the market needs, and thus we encourage and enjoy representation within the organization from a variety of suppliers and innovators, including incumbent vendors, startups, and even researchers (who often are too far removed from commercial concerns about products and services to work effectively enough in standards development). But important to note is that we strongly encourage and consequently enjoy significant participation from SDN customers, including our entire Board of Directors and the many other operators in our ranks.
Finally, in such a diverse ecosystem no one can do everything. That is why we collaborate so closely with other organizations, including OpenDaylight, OpenStack, Open Compute, Internet2, US Ignite, and all the major standards organizations.
Dan Pitt
Re: Excellent topic to expose

I'm glad that Dan Pitt was willing to stand up and offer a response - it's interesting hearing his perspective.

I think Ethan highlighted an important issue though, which extends (naturally) way beyond SDN, and that is the use of the word "Open". It's certainly abused... Offering an API to integrate with does not make it open any more than by Microsoft Windows providing libraries, it's an "open development platform". Ok, anybody can develop on the platform, but the platform itself is far from "open".

Maybe ... and I'm just spitballing here ... there's a use for the term "Software Defined Openness"? I shall now whip myself for going there.

Re: Excellent topic to expose

Oh my goodness jgherbert, you have outdone yourself now. "Software Defined Openness" takes the cake -- you will have to add it to the list on your blog.

I too am grateful to Dan Pitt for sharing his thoughts with us here.

Re: Excellent topic to expose

Thanks, Susan.

I am currently punishing myself for that little outburst by forcing myself to read FORTAN77 manuals. :-)

Re: Excellent topic to expose

Oh, I'm not sure there's any reason to be THAT hard on yourself!

Re: Excellent topic to expose

Wow, that is some list jgherbert compiled! My favorites are "software-defined buildings" and "software-defined vision correction." Incredible.