White Paper

How an Effective SD-WAN Deployment Can Help You Solve Countless Challenges

Software-defined WANs deliver powerful capabilities such as greater security, connectivity and visibility.
  • by Robert Herriage
  • |

The vast growth of networked applications and the number of devices connected to the Internet of Things in recent years have placed immense stress on wide area networks. Organizations that have deployed WAN solutions are finding that they face a growing challenge in managing this complexity. 

Software-defined wide area networking solutions are designed to overcome these obstacles. SD-WANs, which consist of physical or virtual appliances and a central controller, use overlay networks to connect branches directly to data centers, cloud services and each other. SD-WANs simplify network operations by enabling administrators to remotely push out policies from a central management tool. These policies allow for the efficient use of different forms of transport by building secure overlays and prioritizing applications, which can improve user experience, network performance and agility while reducing network costs.


The average percentage increase in network traffic each year

Source: Cisco Systems, “Can Your WAN Keep Up?” March 2018

Many of the use cases for SD-WAN are inherent in the technology, meaning organizations that adopt SD-WANs will automatically realize their benefits. Organizations can solve countless challenges with an effective SD-WAN deployment.

Branch connectivity: Traditional networks employ a hub-and-spoke model, routing traffic, hop by hop, to an enterprise data center to inspect traffic, then moving it along to its ultimate destination. This model can hamper network performance, especially considering that most distributed workforces access WANs from branches.

SD-WAN, on the other hand, can connect branches directly to the data center, the cloud or to Software as a Service applications, shortening transit time, reducing overhead, eliminating bottlenecks and enhancing application performance. This can be done with all traffic, or subsets of traffic, depending on organizational business and branch security requirements. Branches also typically have a variety of connectivity types, and the transport independence provided by SD-WAN can help accelerate branch connectivity.

Cloud connectivity: The architecture of traditional WANs was designed long before the invention of cloud computing. It was built on the premise that applications are hosted in a centralized data center, so traffic from branches needs to travel back to that data center to access those applications. Under that model, it’s the most direct route to applications.

But with an increasing number of cloud-based apps, backhauling traffic to a central data center before routing it to the cloud slows down the network and degrades application performance. SD-WAN can transport data directly from the branch to the cloud.

Security: When asked about their top SD-WAN concerns, 36 percent of worldwide respondents ranked security first, and 72 percent put it in their top three, according to a 2018 survey by Gartner. Security is also a main driver of SD-WAN adoption. The capability to provide a secure overlay to trusted devices over an insecure medium, such as the internet, is mandatory. However, additional key security capabilities such as application-based firewalls, intrusion prevention systems, URL filtering and other unified threat management capabilities allow organizations to consider moving to a decentralized security model.

Instead of backhauling cloud traffic to the corporate data center for inspection before routing it to the cloud, an SD-WAN solution leveraging these advanced security features can connect branches to cloud-based apps through secure direct internet access. Organizations can utilize multiple ways to get access to these security features, such as being embedded directly in the SD-WAN software stack or in integration with other cloud-based security services.

Visibility into network operations and traffic: Seventy percent of application outages stem from network issues. In most organizations, users are employing more bandwidth-heavy applications, more of which are cloud-based or SaaS solutions, and they’re using more devices, resulting in network congestion, packet loss and outages. SD-WAN provides administrators with a bird’s-eye view of the network, so they can easily pinpoint issues in the network and take immediate steps toward resolution. This visibility can also greatly assist administrators in capacity and application prioritization planning to proactively improve user experience.

Application control and prioritization for quality of service: SD-WANs allow administrators to route some traffic using multiprotocol label switching and some on more affordable broadband internet circuits to ease congestion, improve application performance and reduce networking costs, ultimately resulting in improved user experience.

In addition to giving administrators the ability to route traffic along different forms of transport, they can easily prioritize mission-critical applications over others. That way, users on a videoconference sales call aren’t hampered by network traffic from colleagues watching YouTube videos during their lunch break. Using quality of service capabilities in SD-WAN solutions, administrators can deprioritize less important apps to ensure that critical applications have the performance they need.

Centralized management: On a traditional WAN, the control plane is housed within each router on the network, and traffic is routed along a hop-by-hop architecture. New policies or changes require complex manual configurations, generally to multiple devices.

By shifting the control plane from the branch routers to a central tool, administrators can see across the network and manage it simply by centrally pushing out policies to all the branches. They can even bring new branches online remotely within hours. That simplifies and strengthens network management, giving administrators more control over traffic, security and application prioritization.

Support for a cloud-first strategy: All of the above use cases — branch and cloud connectivity, security, visibility into network traffic, application prioritization and centralized management — come together to make SD-WAN the right solution to support the cloud-first strategies deployed by many organizations. Traditional WANs were designed for applications hosted in a central data center. SD-WANs were created for the specific demands of cloud computing.

To learn more about the benefits of SD-WAN, read the CDW white paper “A Software-Defined Upgrade to Wide Area Networks.”