Understanding the Basics of SD-WAN

Unlike traditional WANs, SD-WAN is a flexible, scalable solution that enables enterprises to securely and efficiently route traffic across the Internet directly to SaaS and IaaS. This improves application performance, resiliency, and productivity while reducing IT costs.

An ideal SD-WAN solution supports both MPLS and internet connections, offers centralized policy management, prioritizes traffic on business intent, and delivers improved visibility. It should also support WAN optimization and security features such as an advanced next-generation firewall.

How SD-WAN Works

A traditional WAN network relies on MPLS connections for application delivery. But today’s cloud-based, bandwidth-hungry applications need more than just a single MPLS link. Enterprises need to deploy more reliable connectivity to maximize performance and deliver a high-quality user experience. That’s where SD-WAN comes in.

What is SD-WAN? A managed SD-WAN solution establishes a software layer between an organization and its physical WAN network through encrypted tunnels. At each site, an SD-WAN device communicates with the centralized management portal to receive and enforce custom-defined configurations and traffic policies. It then directs network traffic to the most suitable WAN link based on existing policies and real-time performance data.

SD-WAN enables IT to prioritize traffic and allocate bandwidth on the fly based on business priority, ensuring mission-critical apps always get the best performance possible. It also helps reduce operational costs by directing traffic over more cost-effective, readily available broadband Internet rather than expensive MPLS links.

Finally, SD-WAN provides secure connectivity that only authorized personnel can access sensitive information as it travels across the public Internet. This ensures that even if an attacker gains access to the network, it won’t be able to view or steal valuable information. This is a key differentiator from traditional networking infrastructure.

SD-WAN vs. WAN Optimization

SD-WAN delivers performance, security, and resilience by overlaying atop existing multiprotocol label switching (MPLS) VPNs and broadband Internet connections (LTE, cable, fixed wireless, and more). It offers the flexibility to securely connect sites, data centers, and multiple clouds without the cost of dedicated connectivity.

An important aspect of SD-WAN is that it is a platform rather than a piece of hardware. This decoupling of the control plane from the data plane allows an SD-WAN to see your network landscape in real time and make decisions about where and how to route traffic based on policy rather than pre-programmed rules that may or may not be applicable.

A business-driven SD-WAN is self-learning and continuously adapts to changes in the network. It adjusts routing and policies in real-time, delivering optimal application performance under any network conditions, including congestion or impairments. In the event of a transport outage, it can handle a full switchover seamlessly and in a way that minimizes the impact on business-critical applications. It also enables organizations to establish local internet breakout of IaaS and SaaS applications to bring them as close as possible to users for improved performance while ensuring the corporate network is kept secure. An integrated WAN optimization solution adds to this functionality, allowing businesses to optimize TCP and non-TCP traffic.

SD-WAN vs. WAN Acceleration

SD-WAN leverages network software services that decouple from the underlying hardware, virtualizing WAN connections. This enables businesses to connect their branches, networks, cloud environments, and applications with lower latency, higher performance, better security, and ease of deployment and central management.

The programmability inherent in SD-WAN is also the basis of its big brother, Software Defined Networking (SDN). SDN separates the control and data planes, allowing routing to occur in software rather than specialized hardware devices. This allows businesses to choose from various hardware devices, including commodity x86 platforms, without being locked into single networking vendor hardware.

With traditional networking approaches like MPLS, traffic created in the branch must be backhauled to a central internet security point at the head office, which takes time and decreases application performance. With an SD-WAN solution, this traffic is sent directly to the Internet, bypassing the centralized security point and reaching the applications more quickly, improving productivity and the user experience.

The SD-WAN technology running on the CPE monitors the conditions of all access lines and directs traffic based on application requirements and business priorities. Bandwidth optimization features can be enabled to reduce bandwidth costs by enabling stream compression and byte-caching in real time on the fly. Path selection can also automatically redirect bandwidth-intensive traffic to a secondary broadband internet connection if the primary line experiences congestion.

SD-WAN vs. WAN Security

A key aspect of SD-WAN is enhancing network security with application-level policies, micro-segmentation, and unified threat management (UTM) capabilities. This provides the ability to isolate data traffic so that critical business applications have priority. This can also ensure that rogue devices can’t access sensitive data. This capability can help IT teams save on bandwidth costs while delivering the performance and security that real-time, sensitive applications demand.

Another advantage of SD-WAN is using less expensive broadband Internet connections for WAN connectivity rather than more costly MPLS links. This lowers bandwidth costs and makes it easier to add new sites as your business grows. The solution can be managed from a single management portal, so paths to applications are assigned according to their criticality, and you can easily flex your bandwidth to meet requirements.

Unlike basic SD-WAN solutions, which steer traffic according to pre-defined rules programmed via templates, business-driven SD-WAN continuously adapts in real-time. This delivers optimal application performance even when network conditions change, such as congestion, brownouts, or transport outages. It can also provide sub-second failover, averting disruption of critical applications, such as voice and video communications. The solution supports associating multiple direct-to-internet (DIA) lines to improve last-mile network bandwidth and cost through link bonding. In addition, IT can prioritize and steer traffic according to business requirements to reduce bandwidth consumption and improve end-user experience.