SDN basics for service providers
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Software-defined networking (SDN) and Network functions virtualization (NFV) took center stage at Mobile World...
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Congress this year as it became clear that the technology has the potential to revolutionize mobile operator networks. SDN and NFV can enable resource and service orchestration with dynamic provisioning that can take minutes instead of months.
In mobile networks, the need for dynamic provisioning and orchestration
The foundation of Ethernet and IP protocol networks is elegant and simple, but things have become ever more complicated over the years with the introduction of features, such as access control lists (ACLs) and VLANs. This issue has become even more pronounced in mobile core data centers where operators must support control plane functions, such as policy and charging rules function (PCRF), User Data Repository (UDR) for subscriber data management and user plane applications involving complex Layer 7+ processing for rapidly growing video traffic.
Let's take the example of a control plane function, UDR, to illustrate current mobile network operator challenges. Openwave Mobility has deployed a UDR with a customer that has over 100 million subscribers. The UDR is accessed by dozens of applications including the short message service center (SMSC) and the multimedia messaging service (MMSC) in real time for reading and writing subscriber attribute data. It is arguably one of the most critical control plane elements in the customer's network. While the application has been solid over the last 10 years, there are two areas where this application can benefit from the introduction of SDN and NFV.
The first area is related to provisioning lead times. Today the UDR dimensioning and provisioning based on peak traffic forecasts has to be done almost a year in advance to account for setting up hardware, VLANs, load balancing, as well as software installations, configuration, data synchronization, and so on. That's a complex and time-consuming process to say the least. Imagine the multiplicative effect of this challenge for network and IT personnel when you take into account that each application in the network that has its own solution for load balancing, high availability (HA), configuration, monitoring, reporting, and the like.
This has resulted in CFOs sweating with the working capital ramifications of these long lead times. This problem is exacerbated by the fact that, given the long lead times, operators usually end up overprovisioning by 60-100% to ensure that there are no outages on days like Dec 25th, which would be a PR nightmare and immediate trigger for churn of subscribers.
The second challenge that could be addressed by SDN and NFV is a concept that is interestingly not talked about as much in the context of SDN -- separation of application logic and enforcement from corresponding subscriber data. In many applications today, such as the policy and charging rules function (PCRF) and home subscriber service (HSS), the subscriber data and application logic/enforcement are banded together, usually in a proprietary interface, resulting in subscriber data that resides in multiple silos leading to data duplication, storage inefficiencies, data errors, complexity in the application related to HA and ultimately increasing the complexity and time to market for new applications.
How SDN and NFV address mobile network challenges
We know already that SDN and NFV can address these challenges in two ways: dynamic resource orchestration and intelligent service orchestration. Dynamic resource orchestration, involving the principles of NFV, requires a uniform virtualization stack across applications often in the context of a private cloud for operators.
This means that individual applications such as the UDR not only have the capability to run on virtual machines but also have the capability of being auto-elastic during peak load times, with self-configured new instances coming up while maintaining state and critical capabilities such as HA and failover. This ultimately means that operators can reduce lead times for dimensioning and provisioning of resources for an application down to minutes from months. Meanwhile intelligent service orchestration primarily involves the principles of SDN whereby switches, routers and applications at Layer 7 can be programmed from a centralized component called the controller with intelligent decisions regarding individual flow routing in real time. It is important to note that intelligent service orchestration means subscriber policy and profile-aware service chaining at the flow level. In other words to realize this vision of differentiated service offerings by mobile operators will require a centralized data component such as a UDR. The SDN controller will interface with a UDR to truly enable dynamic and subscriber aware service chaining for each flow.
In summary, dynamic resource orchestration in tandem with intelligent service orchestration dramatically cuts down the long lead times associated with dimensioning and provisioning additional resources for an existing application, while also reducing the cost and time to market for new applications. It also goes a step further by providing the capability to deploy subscriber-aware services.
Given that this is a paradigm shift when it comes to how OpenWave's customers deploy and go to market with new services, the reality is that all this will be done very much in a phased approach over the next few years. In terms of functional areas, operators are focusing on OSS/BSS and the services data center as testing grounds for SDN and NFV, where proof of concepts have involved basic resource orchestration capabilities such as deploying applications on virtual machines. In 2013 we will see thought leadership and proof-of-concepts given our interactions and active engagements with mobile operators with regards to SDN and NFV.
About the author: Indranil Chatterjee is vice president of product management, marketing and strategy at Openwave Mobility. Chatterjee has over 15 years of experience in product management, marketing, strategy and software development in the mobile communications and IT industries. Prior to joining Openwave Systems, Indranil was director of product management at Syniverse Technologies, responsible for new product development for wireless applications and mobile analytics. Before joining Syniverse, he served as director of wireless solutions for Alcatel-Lucent. Indranil is a member of the board of bovernors of 4G Americas. He holds an MBA from Duke University's Fuqua School of Business and a bachelor's degree in mechanical engineering from Indian Institute of Technology (IIT), BHU, India.