Let’s face it: The world is hooked on mobile devices. Consumers have high expectations for their wireless devices and expect seamless communication capabilities.

That being said, wireless providers have quite a high-pressure job, and their business is far from easy. Providers face fierce competition and high customer churn, thanks to a saturated subscriber base and low, fixed, "all you can eat," pricing plans. On the other hand, user demand is almost limitless. Despite how much network capacity is allocated, it is sure to eventually be eaten up by apps and media content.

While there is no magic solution to fix capacity problems, can mobile carriers use software defined networking (SDN) to alleviate the stress on their networks and provide additional benefits by embedding more logic and functions into networks?

With mobile data usage on the rise and the looming "mobile data crunch," one of the major concerns for carriers is optimization, specifically in regards to the radio access network (RAN). Much to the industry’s dismay, you can’t just throw bandwidth at this problem and call it a day. If optimization efforts are not coordinated globally, increasing coverage by adding costly towers will also add interference to the existing towers, a sort of “two steps forward, one step back” move. Additionally, we need to consider the Transmission Control Protocol (TCP) links connecting the Internet with mobile devices using the RAN. If not properly managed, these flows will lock-step too long waiting on acknowledgements, resulting in underutilized "dead air."

The amount of data passing through the mobile airwaves can also be optimized. With many users needing to utilize the same air at the same time, it's worthwhile to invest in resources for real-time transcoding of heavy content files and streams. While this could potentially lower picture quality, in most cases it's a far better option than thrashing application engagement for all users. In order to stay competitive, it’s imperative that carriers consider all the optimization options available to preserve user quality of experience (QoE) while alleviating stress on the network.

We know that optimization should be top of mind for carriers, but what about the rest of our devices? Another important consideration is the issue of connecting more "things" (think Internet of Things) in more ways, achieving selective functionality aspects for competitive agility. For example, when connecting instrumentation in cars, we notice the high mobility, yet low bandwidth of the connectivity. However, when connecting security cameras, we see high coverage and bandwidth, yet low mobility in terms of the connections.

The lesson here is that it’s possible for one-size infrastructure to fit all, but it isn’t cost effective. When connecting “things,” carriers need to consider the selective tenancy dimension. Actions can be applied using in-network functions on behalf of enterprises, (such as Ford, GM, Coca-Cola, or UPS), connecting anything from vending machines to delivery trucks. These functions should be specific, isolated, and should not be randomly mixed.

Looking at SDN's applicability for mobility, we can also compare the actions mobile carriers are taking to those previously taken by airline carriers. When faced with rising costs and intense competition, airlines were forced to make changes and “optimize.” This included increasing density, adjusting offerings and prices and the formation of strategic alliances, actions most of us experienced firsthand. Some airlines were also able to utilize sponsorships, implementing marketing campaigns to help with fuel costs.

This same tactic is already being applied by mobile carriers. Through the use of profiling, analytics, and tagging subscribers and traffic to content providers, advertisers are making mobile carriers a part of the application. Elastic caching of hot content and applications also adds to the value and experience aspect of the delivery network in the eye of the content or end application provider, (much more than a "pipe").

It isn’t easy to deliver such a laundry list of selective smart functions into the network using legacy practices. In the past, such functions were delivered by adding capabilities to "special" routers. Routers are in the data path, so they might as well apply additional logic, right? Not exactly! Adding functions to such custom devices is a slow and expensive process, and each additional function degrades the box performance, which then demands complex and slow repartition and re-planning processes. Routers are natural network junctions, but they do not naturally possess a global context of subscribers, functions and services. They are also difficult to configure, and such subscriber configuration (like access control) is very sensitive to any minor link or topology changes.

SDN has tremendous potential for service providers because it can help virtualize carrier networks and connect the "white pages," (subscriber base) with "yellow pages," (set of functions, mobility, content, analytics, security, flow-control, optimization, etc.). To this end, and because of the complexity of service-provider networks we have previously discussed, creating overlays for the existing IP network (underlay) by using meshed computers that form a service delivery network enables for more efficient connecting, chaining, and balancing of subscriber flows, as well as the ability to match them to network functions. In an ideal world, this delivery network architecture is based on standard IP, but is much more IT and transaction processing oriented.

In addition, the technology would virtualize the wireless carriers’ core networks, enabling them to reap the many benefits of SDN within their existing infrastructure, including cost reduction and monetization opportunities. Using this approach, carriers would be able to operate similarly to Internet companies in terms of time-to-market for new features/services, regardless of the fact that they don’t write their own apps and that their networks are geo-distributed.

While the technology may appear complex, the logic and value behind SDN is simple. Through SDN, the carrier network becomes much more functional and completely programmable, dynamically linking (almost in the computer-programming-language sense) subscribers with functions. This approach enables carriers to steer traffic per flow and chain multiple functions while taking into consideration load, tenancy and access control in a global sense. In addition, anything connected to SDN over IP can be virtualized and can move (both subscribers and functions), enabling service providers to adopt data-center practices, commercial off-the-shelf (COTS) hardware, decoupled software, and elastic allocation. These capabilities bring down cost and increase flexibility, giving mobile and content service providers the tools they need to win the battle between delivering services and managing costs.

Are all approaches to SDN created equal? Ultimately, SDN’s separation of control, forwarding, and network hardware from software makes perfect sense. However, networking demands a distributed way to deliver SDN technology, no matter if it’s control, and/or globally aware. Otherwise, solutions can’t scale, withstand local failures and topology changes, or evolve and accumulate application-specific logic. So, yes to SDN for empowering mobile carriers, lowering costs, and increasing agility using cloud practices. But not just any SDN: location-, identity-, and context-aware federated SDN.