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6 Degrees of Separation: SPs Define 'Open'6 Degrees of Separation: SPs Define 'Open'

Light Reading asked a group of major network operators to tell us what the term 'open' means to them, especially with regards to SDN and NFV -- here's what they had to say.

January 23, 2014

8 Min Read
6 Degrees of Separation: SPs Define 'Open'

With the potential impact of software-defined networking (SDN) and network functions virtualization (NFV) now influencing decision-making processes at every major carrier in the world, never has it been more important for communications network operators to get to grips with the term "open" and what it means for every aspect of their operations and culture.

There's probably no other important concept in telecom networking that is so often cited, yet just as often misunderstood, as that of being open.

Openness is often called out as a primary goal of virtualization, as telecom network operators try to move away from proprietary, purpose-built systems (which lock them into specific vendors) and towards more flexible open hardware that lets them mix and match best-of-breed technologies.

There are a number of initiatives based on openness -- OpenStack, OpenFlow, and OpenDaylight, to name a few.

But is there one definition of open for communications network operators? To find out, we asked several major service providers to share their definitions of open, particularly as it relates to SDN and NFV.

Six operators responded. While the answers have some similarities, each is actually quite different. Clearly, "open" is in the eye of the beholder.

One reason for that, as noted by Diego Lopez, senior technology expert at Telefónica SA (NYSE: TEF)'s research division, Telefónica I+D, is that the term open is overused, especially in discussing virtualization. "It seems like you'll have to add the 'open' prefix to whatever you do," he says.

The operator responses clearly show that openness retains its importance, however. The answers, which came via email, showed thoughtfulness, even though some were short and to the point and others much more detailed.

Some of the differences can be attributed to the individual who fielded our email. For example, we queried John Considine, the CTO of Verizon Terremark, the cloud organization, while choosing to ask research executives or virtualization specialists from other carriers. Only one company, AT&T Inc. (NYSE: T), declined to provide a response, although you can get some idea of its view of openness from comments made by Margaret Chiosi, distinguished network architect, in October of 2013. (See ESDN: AT&T Calls for SDN APIs Now.)

The executives who responded are (in alphabetical order):

  • Yves Bellego, director of network technical strategy, Orange (NYSE: FTE)

  • John Considine, CTO, Verizon Terremark

  • Chris Davis, senior director of marketing, Americas, NTT Communications Corp. (NYSE: NTT)

  • James Feger, VP, network strategy and development, CenturyLink Inc. (NYSE: CTL)

  • Diego Lopez, senior technology expert, Telefónica I+D

  • Peter Willis, chief data networks strategist, BT Group plc (NYSE: BT; London: BTA)

The responses highlighted a number of key themes, which are explored in the following pages of this feature:

  • Interoperability

  • Practical functionality

  • Interchangeability

  • Not all industry initiatives are made equal

— Carol Wilson, Editor-at-Large, Light Reading

Only one response -- that from Lopez of Telefónica -- specifically mentioned the word, and cited it as important, but many responses were clearly pitched in this direction.

"In the SDN space, [open] currently implies the ability of freely interconnecting forwarding elements among them and to any control element, without regard of the origin [vendor, open-source, in-house...] of those elements," Lopez says.

Similarly, for NFV, he says, openness means interoperability among virtualized network functions, the virtualized infrastructure on which they run, and orchestrators that validate and apply the VNFs, regardless of their origins.

Peter Willis, chief data networks strategist at BT, says open is all about mix and match: "Open is where a solution can be formed of multiple vendors where any one component can be exchanged for a similar component from another arbitrary vendor."

In the response from NTT Communications, courtesy of Chris Davis, senior director of marketing, Americas, two of the four points shared related to interoperability: "Open Technology whose specification is widely open to public and mutual connectivity is guaranteed"; and, "Open Architecture with de facto standard multiple technologies to prevent vendor lock-in."

The Orange view, provided by Yves Bellego, director of network technical strategy, also stresses multi-vendor capabilities, but adds the requirement for standards.

"Operating large networks, Orange needs to be able to operate networks composed of elements coming from various suppliers," he says. "This requires that network functions are clearly identified and that the interfaces between these functions are open. This was achieved until now through standardization."

Practical functionality
The word "open" is less important than what is accomplished, say our network operator execs. They are not hung up on a pie-in-the-sky open standard.

"If the supplier provides a well-documented, supportable, and scalable development capability to enhance or manipulate their product functionality, then we see that as 'open,'" says James Feger, VP, network strategy and development, at CenturyLink. "The critical component is the ability for a community to use the tools provided."

Verizon Terremark's Considine tackles the practicality issue from an end-user standpoint. Where Verizon is delivering infrastructure-as-a-service to its customers, it shouldn't matter to those customers what the underlying technology is and whether it's open, so long as that end-user receives "very flexible networking options when using our service, and can select the performance levels they choose to receive," he says.

By contrast, when users want to create customized networking solutions that span multiple datacenters or clouds, there will be a need for "compatibility of endpoints," Considine says, and Verizon will support the open networking movement and make sure its platform plays well with others in sharing information in the appropriate format.

"This same approach applies to the other components like OpenStack -- we strive to provide compatibility at the API layer so that customers can federate between their private clouds and public clouds," he says.

Where SDN and NFV are concerned, openness is a goal, but will come in stages, predicts Bellego of Orange. In the early phases, several network functions may be virtualized onto a single server, but will likely be vendor-controlled, as a modest first step that delivers significant operations benefits, he says.

"We will need to review the processes to operate these network functions, to ensure that we master reliability and business continuity," he says. "Then, after this first step, other steps will increase virtualization to reach the point where we can virtualize all of our network functions in the cloud."

Interchangeability: Vendors can't just declare their systems open
BT's Willis provides a very straightforward appraisal of what makes a vendor's system truly open.

"It's only open if that vendor can be replaced by another vendor," he says. "For example, if Vendor X published an interface, then anyone can write an application that uses Vendor X -- that's not open, that's just publication. Open would be if Vendor X could be replaced by Vendor Y or Z. (Sometimes we see something that looks open but is only implemented by a small number of vendors.)"

In addition, vendor systems that look open, but lack sufficient published details to enable interoperability, are not open, Willis says, because the mix-and-match aspect is limited to those vendors with "inside" knowledge.

Adds Verizon's Considine: "Openness just so you can claim that your implementation is derived from open-source has no real value. Openness for the interfaces and connectivity to allow common control, workload portability, and common networking -- yes, there is real value there."

Not all industry initiatives are made equal
Views of the numerous open initiatives differ.

While generally supportive, operators don't view the various industry initiatives that promote openness in the same way.

"Our view of 'open' does not necessarily translate to OpenStack, OpenFlow, or OpenDaylight," says CenturyLink's Feger. "Our view is focused on the purity of the word, meaning we expect 'open' to be something anyone can use and develop against. The process to achieve this should include sticking with industry-based efforts and standards, which could include the series of 'open' efforts previously mentioned, but that isn’t always a requirement."

Telefónica is looking at the work on SDN and NFV by the Open Networking Foundation and European Telecommunications Standards Institute (ETSI) 's NFV Industry Specifications Group (ISG), as well as other initiatives as critical to ultimately developing standards, says Lopez. He sees initiatives such as OpenStack and OpenDaylight as complementary to the efforts of the standards bodies, and even able to accelerate them and/or generate de facto standards.

"Open interfaces based on open standards are essential, and we are actively working on and promoting them in our projects, deployments, and through our participation in fora like the ETSI NFV ISG or the ONF," he says. "There are many ways of making this a reality, participating in formal standardization activities (like OpenFlow or the I2RS and ForCES initiatives in IETF) and promoting approaches based on open source (such as OpenStack or OpenDaylight) as well."

BT also is viewing these initiatives as enabling progress, especially in the early stages of virtualization.

"For a start it makes it much easier to develop and test interoperable solutions," Willis says. "They can also be considered as prototypes that get debugged by a large number of people and organizations. It's also likely to bake openness into the final products we use for live services."

Verizon Terremark's cloud supports and is compatible with OpenStack at the API layer, "so that customers can federate between their private clouds and public clouds," Considine says. But the company isn't using OpenStack as an orchestration layer, as others are, because it doesn't see that as an advantage in the cloud space.

The last word
For this article, the final word goes to NTT's Davis, who, for his fourth bullet, defines open as "Open" Innovation, creating technical innovation by a mixture of open-source software, open technology that is truly multi-vendor, and open architectures. As he concludes, NTT is also working on SDN technology with "an open mind."

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