The Evolution of SD-WAN

The Evolution of SD-WAN

The driving factors for SD-WAN adoption have not been static throughout its history. SD-WAN has evolved through three main stages to meet the business needs of its users.

The cloud has become an inseparable part of the IT enterprise as more applications make the transition to the cloud. Adaptations in WAN infrastructure that arise are necessary to meet the new and shifting IT landscape. Initially, SD-WAN was driven by the need for cost-saving since WAN infrastructure, MPLS, in particular, can be quite expensive. Today, it’s not just cost savings that are driving enterprises to SD-WAN. Enterprises have changed how they work, with features such as cloud, SaaS, mobile workers, and IT requirements to roll out new sites in days rather than weeks while reducing costs at the same time.

SD-WAN has become more than just a network for connecting locations. The rise of cloud, mobile, and business agility demands has required SD-WAN to become smarter by providing security, optimization, intelligence, and better reach. These changes in SD-WAN can be broken down into three phases, reflecting the ways that SD-WAN technologies have adapted over time to the demands of business requirements.

SD-WAN 1.0 Hungry for Bandwidth

In addition to cost savings, one of the initial problems with WAN infrastructure that IT leaders were looking to solve was last mile bandwidth and availability. A workaround enterprises have used to improve site availability, is pairing an MPLS connection with backup Internet connections. However, typically those backup connections are only used in the event of an outage.

The predecessor to SD-WAN provided some improvements with link-bonding, which combines multiple Internet services with diverse technologies, such as xDSL and 4G from different providers. This technology operated at the link layer and improved last-mile bandwidth. These improvements were limited to the last-mile and did not create benefits for the middle-mile. Although the network was not yet virtualized at this stage, the idea was laying the groundwork for SD-WAN and proving to be a solution to the changing needs of enterprise networks.

SD-WAN 2.0 The Rise of SD-WAN Startups

Link bonding only addressed availability of the last mile. For true improvement in WAN performance, routing awareness needs to take place anywhere along the path, not just the last mile. Advanced features beyond link bonding were needed to address current needs. As these new advancements in SD-WAN were being developed, many startups soon appeared on the scene. Competition breeds innovation, and this phase introduced new features such as virtualization failover/failback capabilities, and application-aware routing. These features were driven by the need for improved performance and agility on the WAN. SD-WAN improves agility of the WAN by avoiding the installation and provisioning delays of MPLS and fills the need for bandwidth on demand. Virtualization allows network administrators the ability to manage the paths or the services underneath from a single control panel to configure optimization features.

Optimization of SD-WAN provides application performance that previously required the SLA-backed connections of MPLS. Using application-aware routing and dynamic link assessment, SD-WAN improves WAN performance by selecting the optimum connection per application. SD-WAN met the challenge to deliver the right performance and uptime characteristics needed to provide applications to users.

SD-WAN 3.0 Reaching Out

SD-WAN evolved beyond connecting branch offices — expanding the reach to all enterprise resources to create a seamless network experience. This is a major shift in networking capabilities to create a unified infrastructure for cloud, mobility, and “as-a-service” technologies. SD-WAN provides encrypted Internet tunnels for traffic traversing the WAN. SD-WAN as-a-service can provide a full enterprise-grade, network security stack built directly into its global SD-WAN backbone to protect all location types, including mobile users.

A Roadmap to WAN Transformation

Not all SD-WAN solutions on the market today address all three aspects of WAN transformation. Cato Networks integrates these WAN transformation attributes into one solution and presents a fundamental change in how we think about SD-WAN. By simplifying what can be a complex environment, Cato’s SD-WAN as-a-service helps organizations achieve full visibility into their network, route applications for optimum performance, and provides security for the entire WAN, including mobile and cloud users.

With Cato Cloud, WAN transformation is a full roadmap for streamlining the networking and security infrastructure of the organization to provide application delivery performance requirements now and as future needs arise.

Learn about how Cato Networks’ advanced SASE solution can transform your business.


  • What is SD-WAN?

    Software-defined Wide Area Network (SD-WAN) devices sit in company locations and form an encrypted overlay between themselves across any underlying transport service including MPLS, LTE, and broadband Internet services.

  • What are the benefits of SD-WAN?

    Reduced Bandwidth Costs: MPLS bandwidth is expensive. On a “dollar per bit” basis, MPLS is significantly higher than public Internet bandwidth. Exactly how much more expensive will depend on a number of variables, not the least of which is location. However, the costs of MPLS aren’t just a result of significantly higher bandwidth charges. Provisioning an MPLS link often takes weeks or months, while a comparable SD-WAN deployment can often be completed in days. In business, time is money, and removing the WAN as a bottleneck can be a huge competitive advantage.
    Reliable Network Across the Unreliable Internet: The ability to connect locations with multiple data services running in active/active configurations. Sub-second network failover allows sessions to move to new transports in the event of downtime without disrupting the application.
    Secure Communications: Encrypted connectivity secures traffic in transit across any transport.
    Bandwidth on Demand: The capability to immediately scale bandwidth up or down, so you can ensure that critical applications receive the bandwidth they need when they need it.
    Immediate Site Activation: Bring up a new office in minutes, instead of weeks and months that it takes with MPLS. SD-WAN nodes configure themselves and can use 4G/LTE for instant deployment.

  • What are the key trends driving SD-WAN adoption?

    Enterprises built their networks using legacy carrier services, such a managed MPLS service. These services are expensive, require weeks to months to activate sits, and require waiting for the service provider to make even the simplest of changes.
    SD-WAN offers an escape from that bringing agility and cost efficiencies to IT networking. The SD-WAN connects locations with several Internet connections, aggregating them together with an encrypted overlay. Policies, application-aware routing, and dynamic link assessment in the overlay allow for the optimum use of the underlying Internet connections.
    Ultimately, SD-WAN delivers the right performance and uptime characteristics by taking advantage of the inexpensive public Internet with the security and availability needed by the enterprise.

  • What are the limitations of SD-WAN?

    Lack of a global backbone: SD-WAN appliances sit atop the underlying network infrastructure. This means the need for a performant and reliable network backbone is left unaddressed by SD-WAN appliances alone.
    Lack of advanced security features: SD-WAN appliances help address many modern networking use cases, but don’t help with security requirements. As a result, enterprises often need to manage a patchwork of security and networking appliances from different vendors (Like CASBs) to meet their needs. This in turn leads to increased network cost and complexity as each appliance must be sourced, provisioned, and managed by in-house IT or an MSP.
    No support for the mobile workforce: By design, SD-WAN appliances are built for site-to-site connectivity. Securely connecting mobile users is left unaddressed by SD-WAN appliances.