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What is SD-WAN (Software-defined WAN)?

SD-WAN is the next generation of WAN edge networking. Learn what it is, how it works and how it’s different from traditional branch routing.

SD-WAN (software-defined wide-area network) is a specific application of software-defined networking (SDN) technology applied to WAN connections such as broadband internet, 4G, LTE or MPLS. It connects enterprise networks – including branches and data centers – over large geographic distances.

There is a reason we use the term “software-defined revolution” when talking about SD-WAN. A year ago, conversations with customers around SD-WAN centered on hardware. Now we are focused on the role SD-WAN plays in a holistic move to a software-defined network.

How does SD-WAN work?

SD-WAN involves managing WAN branch routers from a central controller, or creating the “brains” of the network, so that potentially thousands of routers can be managed from a one place.

A main benefit of SD-WAN is that the network is easily managed from a central controller. Network administrators can build policies and seamlessly push them to every device at once, greatly simplifying IT management.

In addition to simplified management, SD-WAN can run over any type of network (such as broadband, fiber, LTE), through any type of service provider connection (Internet, MPLS).

There are four core features of SD-WAN: 

  • Transport independence
  • Application visibility
  • Path intelligence
  • Centralized management

As the SD-WAN market changes, vendors continue to develop solutions that include these features as solution foundations.

SD-WAN deployment

The most common SD-WAN deployment model includes vendor-branded hardware known as SD-WAN edges, but there are also virtual options for the cloud. The edge replaces service provider handoffs – Ethernet, LTE, T1 – and offers routing or switching access to the branch infrastructure.

Network Function Virtualization (NFV) is another deployment model, where virtualization and white box compute platforms are combined. Regardless of deployment model, a physical networking element is required to connect back to the SD-WAN edge. The SD-WAN device must also provide the functionality needed to incorporate the branch into the WAN and the rest of the network.

What are the benefits of SD-WAN?

Organizations are now requiring a higher  level of agility than what traditional WAN designs offer. With SD-WAN technology, businesses can instantly realize benefits such as secure connectivity and endpoint management, transport and hardware independence, bandwidth efficiency, improved application performance and simplified IT operations. The top 8 benefits include:

  • Scalability. Network models are both scalable and cloud-enabled.
  • Transport Independence. Leverage high-speed bandwidth across multiple transports such as MPLS, internet, 3G/4G/LTE, etc. with the right security and quality of service (QoS).
  • Path Control. Utilize multiple WAN paths for resilience and bandwidth efficiency.
  • Application Optimization. Optimize the performance of applications to maximize WAN bandwidth and provide great user experience.
  • Zero-touch Deployment. Quicken the deployment of sites by remotely provisioning new equipment and services.
  • Orchestration. Automate management and orchestration of services to optimize staff time and total cost of ownership.
  • Programmability. Extend the WAN with software-defined and programming extensions via APIs.
  • Flexibility. On-prem and cloud-based deployments are both possible with SD-WAN architecture, based on what is best suited to your policies and processes.

SD-WAN, SDN and traditional WAN

Many of our customers still use legacy service provider circuits, including T1 interfaces, which can be expensive to maintain and carry relatively low bandwidth capabilities. Often this results in paying too much for too little bandwidth when it comes to business-critical services that directly impact revenue.

A variety of services continue to raise expectations much higher than traditional router solutions like software-defined security, WAN optimization and application-aware WAN.

Software-defined networking (SDN) is a way of deploying network infrastructure that simplifies and accelerates operations through automated provisioning, network virtualization, Network Function Virtualization (NFV), service chaining and centralized policy and configuration management.

SDN is programmable by the customer or user while SD-WAN's programming is handled by the vendor. SDN is enabled by NFV within a closed system, whereas SD-WAN provides application routing that can be virtualized or run on an SD-WAN appliance.

Modern SD-WAN solutions have a few main capabilities that separate it from traditional WAN, including transport agnostic WAN connectivity, business application steering, advanced security measures and a simple deployment and operation processes. 

While software-defined solutions provide new innovations for the branch network, traditional WAN practices shouldn’t be ignored. Adopting technology in a controlled way is still the best path for integrating new solutions; this applies to traditional solution design as well.

Processes such as market research, training, pilot testing, migration strategy development and integration tasks are required when implementing SD-WAN architecture and supporting operations. Without comprehensive network planning and design, it will be extremely difficult to realize the full benefits of an SD-WAN deployment.

Which SD-WAN vendor is best?

One problem is that with increasing capabilities and growing popularity, deciding the best solution for your organization can be difficult. A growing number of vendors and new features are coming to market every month and not all SD-WAN solutions are going to meet each business need. This changing market can easily date pertinent information. 

Several vendors offer segmentation and direct internet access, and others provide solutions to support public cloud and colocation connectivity; some placed focus on core routing capabilities that enable better integration into complex architectures.

There are three basic components to consider when selecting an SD-WAN solution: 

  • the solution’s ability to replace existing infrastructure 
  • its functionality when addressing business requirements
  • the ability for it to integrate with your current enterprise architecture

It’s vital that organizations can sort through the noise and identify the actual solution capabilities, aside from what is advertised. Considering the changing requirements of the enterprise network and the rate of today’s innovation, focus on SD-WAN capabilities that are fully tested and in production, while also keeping an eye on road-mapped features.

Lab and consulting services like sandboxes, proofs of concept, workshops and ideation help compare and contrast solutions from different vendors to help identify the best fit for your organization. 

SD-WAN for every use case

Software-defined networks are becoming more relevant in retail and healthcare industries, where guest Wi-Fi is critical to business. Retail stores and hospitals are using wireless connectivity to help strengthen brand awareness and create new experiences for customers and patients.

In addition to customer experiences, organizations from every industry are implementing SD-WAN to improve workforce productivity. Many of our customers are concerned with empowering their employees to maximize their time – whether they’re working on-site or remotely. 

They need their workforce to be able to start working right away, without worrying about connecting to the network or how applications are going to work form a certain location. SD-WAN technology provides optimal service to employees at all times, which helps organizations achieve workforce productivity objectives.

For the ones managing and supporting applications, IT, the modern enterprise network is complex. Many applications now live in the cloud and are consumed through SaaS. Most of company revenue is generated at the branch. The rise of a disparate workforce demands voice and video to improve meetings, communications and ultimately, business relationships.

The result is aging networks that are being pushed to their limits, due to the fact that they were not designed to support modern experiences across the enterprise. SD-WAN offers a way for IT to tackle the stress of managing the modern workplace, because it is built with the modern workplace in mind.

Ready to get started?

The SD-WAN market is constantly changing and adapting to new enterprise needs. It is important to know your unique objectives and desired outcomes that will drive business forward. 

WWT can help design a complete approach to SD-WAN that improves operational efficiencies and helps control WAN costs. Explore the top SD-WAN vendors and identify innovative features of each solution with a WWT SD-WAN Technology Briefing.