This content is part of the Buyer's Guide: Consider SD-WAN products to help simplify network management

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Key considerations before evaluating SD-WAN vendors

Before selecting an SD-WAN technology, organizations must understand what problems they need to solve and assess which implementation option is best suited to their WAN and business requirements.

Software-defined WAN, or SD-WAN, is a powerful and flexible technology that offers organizations improved bandwidth economics, application prioritization and operational efficiencies. SD-WAN supports a wide variety of use cases across a range of verticals, and basically any organization with a distributed workforce can benefit from the technology.

It's important to evaluate your current branch networking requirements before selecting a specific SD-WAN technology. There are many different ways to purchase the technology -- from the spectrum of complete do-it-yourself flexibility to the convenience of a fully managed service offered by SD-WAN vendors. Pricing schemes are complex, with options to buy appliances, licenses to run software on your own servers and software via subscription.

How SD-WAN technology addresses business challenges

As with all IT projects, the best place to start is to understand which problem you're trying to solve and its business value to the organization. For SD-WAN, the problem may be specific to an application, such as Office 365 performance, poor WAN connection reliability, voice-over-IP (VoIP) quality or huge WAN traffic bursts due to video transport. The business challenge may also be more general in that WAN bandwidth requirements to office locations are growing faster than the budget for WAN bandwidth.

Editor's note:

Using extensive research into the SD-WAN market, TechTarget editors focused on 10 leading SD-WAN vendor offerings; this does not include middleware or options offered by resellers or managed service providers. Our research included data from TechTarget surveys and reports from research firms, including Gartner.

Another business case could be related to IT agility. Take, for example, the requirement to rapidly deploy temporary branch locations, like construction sites or pop-up retail stores. Other examples of specific SD-WAN use cases to address specific problems are highlighted below:

Hybrid WAN. SD-WAN technology enables the deployment of hybrid WANs -- specifically, the ability to use two or more WAN links to provide enhanced bandwidth and reliable connectivity to each remote branch. The typical hybrid WAN deployment allows an organization to add high-speed internet connectivity to its existing MPLS branch network. Through application prioritization and traffic load balancing, SD-WAN can ensure critical applications use the best link available at any given time. Hybrid WANs are generally easy to cost-justify based on the performance and economic benefits of internet links.

Branch reliability. Related to the hybrid WAN use case, the reliability of branch communications can be enhanced by the deployment of two or more WAN connections with SD-WAN. Organizations like banks, restaurants and retail stores can suffer tremendous effects to their business -- including lost revenue -- when their branch locations are offline during business hours.

Other industry verticals cite problems of lost user productivity. For example, a key business problem includes lawyers being unable to access critical applications and information when access is down.

Branch security. Security requirements at branch locations can vary widely depending on the applications in use, vertical industry, and specific regulatory and compliance requirements. Industries, including finance, public safety, healthcare and retail, are all subject to specific security regimens. SD-WAN vendors' technology provides enhanced security for relatively unsecure internet links and can interoperate with existing network security infrastructure, like firewalls at branch or centralized locations.

Unified communications (UC). Enterprise communication services, including VoIP and video, require specific network capabilities in order to deliver a high-quality user experience. UC requires WAN connections with adequate bandwidth, low latency and minimal packet loss. SD-WAN enables organizations to prioritize UC traffic over WAN links, monitors UC traffic performance and adjusts the network to improve quality according to IT requirements.

In a hybrid WAN use case or for internet-only links, SD-WAN can remediate the performance challenges often associated with unpredictable internet bandwidth. Each of the leading SD-WAN vendors has its own proprietary method for application identification and traffic prioritization to enhance UC quality.

Temporary sites. Branch locations can change on a regular basis, whether they're part of normal business projects, like a new building site; business conditions, such as a new or changing store location; or changes resulting from a merger and acquisition. SD-WAN enables IT teams to rapidly deploy WAN connectivity to new locations within days. Using SD-WAN's zero-touch deployment and centralized management, IT can ship an application to a location and have untrained personnel connect the box to the internet or 4G Long Term Evolution (LTE). The remote appliance can phone home and be remotely configured by central IT resources.

SD-WAN has the power to tackle a wide range of WAN challenges that address use cases, vertical industries and geographies.

Remote and mobile locations. Many organizations have critical applications and a workforce at small or remote locations. Others, such as those in public safety, have IT processes that are truly mobile. SD-WAN can be deployed as part of a remote access service for mobile and work-at-home employees. It can help provide secure connectivity and improve performance for critical applications.

Services from SD-WAN vendors offer 4G LTE links to provide high-speed connections to truly mobile sites. As more IT applications become distributed at the edge -- e.g., internet of things -- SD-WAN's remote and mobile capabilities become increasingly important.

WAN architecture. The WAN provides critical connectivity between remote branch offices and central locations. It also enables the remote workforce to access cloud-based applications, including Office 365; UC; remote compute and storage services, such as Amazon Web Services or Google; and specialized applications, like Salesforce. The growth of UC and cloud-based applications continues to stress the bandwidth and latency requirements for most distributed organizations.

Here are some initial questions to consider regarding SD-WAN architecture that allow an organization to analyze its current and projected requirements for its WAN:

  • What is your current and near-future branch network architecture?
  • How many locations?
  • How many employees at each branch?
  • What are your bandwidth requirements?
  • What's your current spending on WAN connectivity?
  • How will increased bandwidth requirements affect this spending?
  • Who are your current communications suppliers for WAN bandwidth?
  • Do you need to set up connectivity to new or temporary branch offices?
  • How often do your branches change location?

Which SD-WAN technical capabilities are required?

SD-WAN technology comprises a comprehensive and growing catalog of capabilities. IT organizations should evaluate their specific requirements as they research the SD-WAN market. Here are some questions to help evaluate which SD-WAN capabilities the organization requires:

  • What are the critical applications at your branch locations?
  • Do these applications reside in your data center or in the cloud?
  • What cloud-based applications require prioritization?
  • Do you currently -- or plan to -- run latency-dependent UC applications, like voice and video, at the branch?
  • What is your current branch security architecture?
  • What are your key security requirements?
  • Do you require WAN optimization for specific branch applications?
  • Do you operate guest Wi-Fi at your branch locations?

SD-WAN buying options

Organizations can choose to install and manage SD-WAN technology themselves, or they can outsource part or all of the process. A wide range of network resellers, managed service providers and communications service providers are available to assist with SD-WAN implementations. Organizations should carefully evaluate their internal capabilities and costs compared to external managed resources.

SD-WAN vendors offer a wide array of choices when it comes to selecting a specific SD-WAN implementation. Organizations implementing SD-WAN internally, as opposed to selecting a managed service provider, have three main options:

  • Appliances. The traditional network hardware device, these SD-WAN services come in an integrated box that's typically a modified server.
  • Software licenses. Organizations buy or license SD-WAN software to run on their own servers at the branch and data center.
  • As a service. The SD-WAN technology provider delivers SD-WAN as a service. Any devices or software at the branch are owned and operated by the supplier.

As a technology, SD-WAN has the power to tackle a wide range of WAN challenges that address use cases, vertical industries and geographies. Before you begin vetting SD-WAN vendors, it's important to prioritize your specific business challenges and to answer a range of questions about your WAN environment.

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