What is SD-WAN (Software-Defined-Wide-Area Network)?


SD-WAN technology is a modern way to set up an enterprise network using secure connections to data centers and broadband links across many geolocated offices. Routing data is handled virtually using software for transport services instead of traditional routers with routing tables. Packets are given a label and a predetermined path when they are sent from a sender to a recipient to improve performance. SD-WAN technology makes cloud connectivity more flexible, convenient, and secure.

How an SD-WAN Works

Traditionally, routers were used to direct traffic across the Internet, and they are still prevalent today. When you send communication over the Internet, data is sent to a central location where the packets are analyzed and routed. Router tables are vast resources that create a bottleneck during data transmission. A lookup for the fastest path is performed and dynamically created.

In an SD-WAN environment, data is labeled with a predetermined path attached to the packet. This eliminates the inefficiency of sending packets to a central location where the path is dynamically determined. Instead of using a central office to determine the way packets are routed, an SD-WAN relies on the application. Distributing control of traffic to each application improves data transfer speeds. For large enterprise networks, data speeds are crucial for customer satisfaction and employee productivity.

Why SD-WAN is Important

As more businesses integrate cloud computing into their architecture, they must maintain performance during migration. It’s also just as important to have the infrastructure that supports business applications. Leveraging the latest technology like SD-WANs keeps businesses current and helps them avoid supporting antiquated legacy architecture.

SD-WAN integrates well with cloud platforms, which is its primary benefit over WAN technology. For instance, Salesforce is commonly used in sales departments, but it’s a large project for organizations to set it up to work with local resources. SD-WAN technology works well with SaaS (Software as a Service) and PaaS (Platform as a Service) providers. It integrates well with Salesforce, Office 365, Dropbox, and other widely-used platforms.

What is the Difference Between SD-WAN and WAN?

Most IT professionals are familiar with the traditional Wide Area Network (WAN) setup. The Internet itself is one large WAN where data travels first to an Internet Service Provider (ISP) and then to a target location that could be across the globe. A traditional WAN is just multiple Local Area Network (LAN) connections across different geolocations. It could be two separate buildings across the street from each other or two offices in different states. The connections are made using routers and switching that prioritizes traffic.

An SD-WAN setup has some of the features of a traditional WAN, but the following features are unique to SD-WAN architecture:

  • Agnostic to switching protocols. Instead of worrying about the switching protocol used to route traffic, SD-WAN architecture relies on the application to assign a path to data.
  • Load balance across each location. Administrators can specify where applications will run and share resource usage across data centers.
  • Reduces complexity. Using an SD-WAN, administrators no longer need to worry about adding complexity to a WAN. Professionals can more easily understand the settings and configurations required to set up the network.
  • Security and VPN technology. Although a WAN can also be secure, an SD-WAN can be more easily set up with VPN to encrypt and protect data sent across the network.

What are the Benefits of an SD-WAN?

Better performance and flexibility aren’t the only two benefits of using SD-WAN technology. Using an SD-WAN over traditional WAN technology has several other benefits. Here are a few of them.

  • Prioritize traffic. With a traditional WAN, all traffic is considered the same, but it’s isolated from other traffic to prevent packet loss. Usually, certain network traffic is more critical than other applications. For instance, voice calls should be a priority over general traffic. Prioritizing traffic gives speed and bandwidth to more critical applications.
  • Security. MPLS connections are secure by keeping traffic private from other data, but SD-WAN technology incorporates VPN into data transfers. VPN security is much more reliable and can be easily configured with the current infrastructure.
  • Scalability. WAN technology is older and much less manageable when scalability becomes an issue. SD-WAN is much easier to scale and configure when adding new offices.
  • Cheaper IT costs. MPLS technology is expensive, and SD-WAN lets businesses use cheaper fiber, cable, or DSL connectivity.
  • No single point of failure. Instead of using a single-point connection with MPLS, SD-WAN gives administrators the option to use multiple links across locations. A dual-link connection can be used as a failover if one fails.

A true cloud-connected enterprise should have multiple locations to support users at different geolocations. SD-WAN technology makes it much more convenient and scalable for an organization to quickly add a remote office and keep it secure from eavesdropping.

When Should an SD-WAN Be Used?

Adding an extra office or cloud location is the first step in considering an SD-WAN. There are several scenarios when an SD-WAN would be more beneficial compared to traditional WAN technology.

Because you can prioritize traffic, an SD-WAN is beneficial when several applications take large amounts of bandwidth. With an SD-WAN, the administrator can set the path data will take as it travels across circuits. Voice and media could take the path using one circuit, and then internal applications could be given a lower priority and routed across another circuit. With multiple circuits, high-bandwidth applications can be routed over circuits with more capacity compared to other circuits.

Some organizations work with cloud data centers to host applications and data. An SD-WAN is much more easily configured to work with cloud locations versus a WAN. Any time you use a cloud location, an SD-WAN should always be the solution. Traditional WAN technology is better for connections across offices close in proximity.

Any time an organization shares sensitive data from one location to several satellite offices, an SD-WAN can be configured to work with a VPN. VPN is a more secure method of data transfer across circuits, especially the Internet.

Traditional WAN connections can be expensive. An organization can cut costs by switching to SD-WAN, but many don't want to make significant changes with existing connections. Organizations can set up a hybrid system where traditional MPLS circuits stay active, but any new office connections work with SD-WAN technology. SD-WAN can also be used as a failover across all connections.

What Does SD-WAN Have to Do with SDN?

Shopping for networking technology, administrators will run into the term Software-Defined Network (SDN). Although it might seem like the two technologies are similar, they are distinct in what they do for an organization. SDN is a technology used in local area network (LAN) management, while SD-WAN is used for managing network resources across multiple sites and the technology used to connect them.

SDN networks can also prioritize traffic and let administrators control configurations from a central location. The primary difference is that control and prioritization are configured for a LAN rather than a WAN. SDN networks will still use traditional routing and infrastructure and can be added to existing network environments where WAN or SD-WANs are set up.