Understanding SD-WAN Architecture – A Comprehensive Overview

The SD-WAN architecture enables organizations to avoid costly service contracts, but technology teams must understand what they need before buying. Pre-purchase steps include aligning business goals with the technology’s capabilities. These include micro-segmentation, which helps IT staff organize network traffic; policies that describe application characteristics and failover options; and real-time line monitoring. A centralized controller manages all of this, providing visibility in real-time.

Network Topology

What are the basics of sd-wan? When an organization migrates to SD-WAN, it can expect better performance and lower costs. The network can optimize traffic based on business policies, allowing greater flexibility and agility. In addition, automation can reduce human error. With this, businesses can operate more efficiently and experience less downtime. To achieve this, the network needs to be scalable and secure. It must be able to connect locations using significant types of data services, including fiber, xDSL, cable, 4G/LTE, and MPLS. It also needs to support link bonding, which combines multiple Internet connections to increase last-mile bandwidth. It should also be able to identify different applications and apply appropriate security. Finally, it must be able to support both MPLS and the Internet. It should be able to offload non-critical traffic over the Internet and direct critical traffic through a high-performance private backbone. It should also provide redundancy and performance for remote locations, with the ability to scale up or down as needed. Most organizations used an MPLS-only model for their WANs in the past, but this approach can be expensive and slow to implement. Many enterprises are moving to a hybrid approach, with some traffic on MPLS and the rest offloading to SD-WAN. In the future, some experts believe that most enterprises will shift to a pure Internet-based solution.


In addition, to secure connectivity, SD-WAN should provide advanced security deployed in a cloud service so that it doesn’t have the scaling issues and management challenges that come with hardware appliances or virtual network functions (VNFs). The infrastructure should also support a firewall as a service that eliminates the cost, complexity, and maintenance of deploying and managing local security appliances. The WAN architecture should also optimize application performance to ensure that applications run smoothly, despite Internet-borne threats like latency and packet loss. The ability to detect and prioritize application traffic will help improve user experience and increase productivity. One of the critical elements of the WAN architecture should be link bonding that combines multiple types of Internet connections at the link level, improving last-mile bandwidth. This will ensure that other relationships continue to carry traffic if a connection experiences an outage or degradation. The WAN architecture should also allow the automatic provisioning of application policies aligning with business intent. By intelligently steering traffic based on policy and continuously measuring performance, SD-WAN will maintain application performance, even as it remediates performance degradation by failing over to better-performing WAN links. This will help to improve user experience and reduce costly downtime for critical applications.


An SD-WAN can automate numerous processes for improved efficiency and security. This can lower operating costs by reducing human error, speeding up operations, and improving quality of service (quality of service). To implement an SD-WAN, IT staff creates a virtual abstraction that sits on top of physical WAN networks and manages those networks’ devices. The centralized management system can set governance policies, configure network settings and perform performance monitoring on devices in the SD-WAN layer. This allows IT teams to make changes that can directly impact application and WAN network performance. In addition, an SD-WAN can provide redundancy and automatic failover between WAN connections for improved application performance. This can reduce reliance on expensive, leased MPLS circuits by sending low-priority data over cheaper public internet connections and reserving private links for mission-critical data. It can also optimize connectivity to the cloud and SaaS applications by directing traffic over direct routes that bypass the data center. This can help companies avoid costly telecommunications circuits often subject to packet loss and jitter, negatively affecting application performance. By analyzing performance and bandwidth needs at each site, an SD-WAN can determine the best transport mix and automatically redirect traffic when there is a problem. This can provide sub-second failover and avert a business outage or service interruption.


Unlike traditional networking models, where traffic from branch offices is backhauled to a centralized internet security point in the data center, SD-WAN enables secure, direct connectivity. This eliminates the need to send data back and forth between branches and headquarters, which reduces latency and boosts application performance. The software layer in an SD-WAN creates a virtual overlay that abstracts underlying private or public WAN connections like MPLS, internet broadband, fiber, and wireless. This allows enterprises to keep their existing equipment and enables real-time application traffic management across the links. IT staff can program network edge devices with low or zero-touch provisioning. Another essential feature of an SD-WAN is application optimization. IT staff can identify which applications are sensitive to latency and packet loss, and the system can automatically optimize those applications for the best performance. This improves availability and increases user productivity by reducing a specific application’s bandwidth or using multiple routes to deliver data more efficiently. A final benefit is cost savings. By utilizing regular Internet connections for business-critical data rather than pricier MPLS links, businesses can save on hardware, deployment, and maintenance costs while maintaining last-mile connectivity that’s reliable and fast. Internet connections also enable organizations to scale up or down their SD-WAN deployments as necessary. An SD-WAN’s centralized management makes this more accessible, eliminating the need for separate management systems to manage each site’s WAN infrastructure.

Leave a Comment