SD-WAN industry development requires VNF evolution

Like any successful technology, the Software Defined Wide Area Network (SD-WAN) market is experiencing a growing dilemma related to market awareness, with many vendors extending the term to their traditional solutions or simply using it as a direction of development, but SD-WAN is indeed the trend of the industry. As the wide area network gradually becomes the performance bottleneck of various cloud services, the SD-WAN market will continue to grow and develop. This evolution will happen in every area where software defines everything, such as enterprise data centers, virtual network functions (VNFs), and how they are used to create customized WANs on demand.

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The huge growth of SD-WAN this year, and the continued growth expected in the next few years, is the continued evolution in the data center. That is, from manually configuring a group of servers and storage devices to a software-defined architecture, where servers and storage devices (virtual or physical) can be managed and operated through a software-defined architecture, which means fewer manual errors, lower costs, and more efficient operation of the data center.

As an industry, when we implement some data center methods into the WAN, we must pay attention to the huge difference between the data center network and the enterprise WAN. That is, the data center local area network (LAN) has sufficient capacity and bandwidth, and unless they are misconfigured, it is never a performance bottleneck. For the enterprise WAN, its branch offices are connected to the Internet through WAN connections (MPLS, DSL, cable, fiber, T1, 3G/4G/LTE, etc.), and the performance bottleneck is almost always the WAN. This is why SD-WAN has been able to quickly become popular, because SD-WAN provides a way to alleviate this problem.

However, as WAN complexity continues to grow, and as enterprises run multiple clouds and cloud models simultaneously, there is a growing need to add automation and programmability to software-defined WANs to ensure performance and reliability. Therefore, VNFs that can address this WAN performance bottleneck have the opportunity to change the way enterprises connect to private, public, and hybrid clouds. VNFs that extend beyond a single location but can cover WAN networks will have the ability to add programmability to the WAN. At some point, the "software-defined" nature of the data center will extend to branch offices, including the WAN connections between them.

So, what do programmable VNFs and VNFs that solve WAN bottlenecks look like? These VNFs can perform overlay tunnels of certain flow logic and can solve network problems on a flow-by-flow and packet-by-packet basis. These intelligent VNFs are able to diagnose problems, issue alerts, and most importantly, provide solutions to solve these problems. In other words, before SD-WAN, IT managers needed to deal with network problems urgently, but with these VNFs, they don't need to. With VNF-based SD-WAN, the network will become smart enough to proactively solve problems, and in most cases, the problems will be solved before they even affect applications, services, and user experience.

The addition of specific VNFs for SD-WAN will start with the most pressing needs, which are usually latency and jitter sensitive applications such as voice, video and unified communications (UC) type applications. Even now, VNFs are used to solve these problems. For example, the CIO has a VNF that dynamically and automatically directs VoIP/SIP traffic caused by high latency, jitter and packet loss, and another VNF supports cross-flow and latency optimization for chatty applications.

Another example is that a VNF can be built in minutes, which is designed to steer non-real-time traffic away from expensive WAN links and apply header compression to real-time traffic only if packet loss or latency exceeds a certain threshold within a certain time, while updating syslog and telemetry data. With this flexibility and advanced features, VNF will become a solution to WAN-related problems.

A VNF load balancer is another overlay that has the ability to load balance traffic across WAN links. Because a VNF load balancer is essentially software code that can be deployed on an SD-WAN device, it has the advantage of leveraging various types of intelligence and adaptation to optimize WAN performance. VNF load balancers work with standard routing protocols so that they can be injected into the network, such as seamlessly connecting between WAN modems and firewalls/routers.

Clearly, VNFs are part of the next evolution of SD-WAN, bringing intelligence and flexibility to the enterprise WAN. As 2017 progresses, we will see more and more innovation in the SD-WAN space, including the expansion of data centers to software-defined architectures.