SD-WAN: Fast and Affordable Remote Connectivity

Adapting to a New Era

The days of IT providing core business services out of a central data center or server closet are winding down. Today’s focus is on providing seamless, reliable access to externally hosted services. “When all traffic was bound for a central place, network functions relating to bandwidth optimization and security would be implemented centrally,” says Fred Chagnon, research director of Info-Tech Research Group’s infrastructure practice. “With applications being hosted externally, these functions need to be deployed closer to the edge of the network.” SD-WAN provides the means to do so within a more distributed architecture.

With more applications heading to the cloud, traditional hub-and-spoke topology and multiprotocol label-switching (MPLS) architectures are becoming less efficient for direct access, notes Sanch Datta, CTO of FatPipe Networks. “Additionally, the quality of internet connections has improved over recent years,” she says. “These factors are leading organizations to look at SD-WAN as a means to manage their WAN.”

SD-WAN creates an agile, software-driven approach to WANs. “It replaces traditional WAN networking hardware, such as command-line interface–configured routers, with centralized management, applying SDN technology to WAN connections to most effectively deliver applications to users across long distances,” Dobies explains. “The goal of SD-WAN is to reduce the costs of private WAN links, increase performance and make networking more agile for the cloud.”

Another key SD-WAN benefit is its inherent ability to control traffic at the application level, establishing intelligent policies about where real-time traffic, such as video and voice, are to be routed. For instance, an SD-WAN can detect business-related traffic and give it preferential treatment. Nonessential traffic, headed for sites such as Facebook and YouTube, can be given lower priority. “An organization that has the ability to categorize its traffic in terms of business use and priority will find itself with more discrete control over how to shape that traffic across their SD-WAN,” Chagnon says.

SD-WAN Components

There are four basic components that exist in almost every SD-WAN solution, Johnson notes, although these features may be offered in different forms by solutions from different manufacturers.

1. Controller:

An SD-WAN controller directs the network’s operation and provides network-wide intelligence. The controller is generally situated either in a data center or cloud, either in a physical tool or as software.

2. Appliances:

An SD-WAN appliance is placed at every location that’s participating in the network. The appliance terminates the virtual tunnels, participates in routing, may include firewall functionality and provides local intelligence for traffic management. Appliances can be physical, virtual or offered as a virtual network function running on a customer premises equipment network. Software-deployed appliances are also available in the cloud, where they may be owned by the provider and offered as a service.

3. Virtual tunnels:

Integral to an SD-WAN, virtual tunnels are connections created from underlying networks — such as MPLS, broadband, wireless or satellite — and terminated on either end by an SD-WAN appliance. All SD-WAN traffic is intelligently directed along these tunnels.

4. Management system:

A management system, or orchestrator, is found in every SD-WAN solution. The component is used to configure the network, define policies, manage tasks and troubleshoot problems. A simple, straightforward management system makes it easier to deploy, operate and maintain an SD-WAN.

Getting On Board

“Once the organization has identified its primary SD-WAN needs, it needs to be clear with the vendors it’s considering and really understand how those vendors can meet those needs,” Johnson advises. A knowledgeable solutions-focused external partner can help an organization select the most appropriate vendors.

Datta believes that solution flexibility and adaptability are essential to a successful SD-WAN deployment. “The organization should choose an SD-WAN platform that has the flexibility to provide the features in each location that the specific location requires,” she says.

When evaluating SD-WAN solutions, it’s also important to consider how well the technology will work with and benefit from other network services and practices. “Specifically, network security components, WAN optimization, and visibility into end-user experience and application response times are all critical to achieving and maintaining fast, agile and secure delivery of applications across the distributed network,” Dobies says.