Etay Maor is Senior Director, Security Strategy for Cato Networks, a developer of advanced cloud-native cybersecurity technologies.
Wide area networks (WANs) have been around for half a century. WAN technology was originally developed to connect geographically dispersed areas over considerable distances, allowing businesses to communicate securely and reliably between offices in different cities and countries. Corporate WANs have evolved, growing more complex and costly for organizations to maintain. Modern enterprises not only connect to branch offices, but they must also connect to cloud-based infrastructures, data centers and elsewhere. As a result, applying security layers to WANs can pose challenges.
Organizations are increasingly leaving behind the WAN framework in favor of migrating to a software-defined WAN (SD-WAN). To understand why SD-WAN is a natural successor to traditional WAN, let’s focus on the differences between both approaches and how SD-WAN overcomes some of the limitations of conventional WAN.
Overview Of WAN
WANs are built using hardware appliances like routers and typically rely on multiprotocol label switching (MPLS) technology to control and route network traffic. Since WANs involve dedicated circuits, they’re usually faster and more reliably secure than the public internet. Moreover, WANs offer organizations full control over the network, enabling them to establish routing policies and prioritize traffic flows as needed.
Limitations Of WANs
Although WANs offer benefits, they are far from perfect. IT teams must invest a great deal of effort in planning, configuring, managing and securing the different layers of hardware. This heavy dependence on hardware creates scalability challenges, as modifications and upgrades necessitate meticulous planning, and the installation of additional capacity often involves manual intervention. Policy configuration can be complex and prone to error and misconfiguration. Additionally, managing specialized hardware requires specialized skills; such resources are difficult to find, train and retain in-house.
MPLS has its own limitations as well. Built for point-to-point connectivity, MPLS is not well suited for cloud applications; this often involves backhauling traffic to the corporate data center, and this increases latency and impacts performance. Additionally, not every ISP or telecom carrier can provide the dedicated support that is needed to maintain an MPLS connection.
In a branch office setup, organizations will typically backhaul traffic to the regional data center for security inspection. However, since most employees today use cloud applications for work, routing this traffic back to the regional data center is extremely inefficient and suboptimal, to say the least.
Overview Of SD-WAN
As the name suggests, SD-WANs is a software-based approach to managing the Wide Area Network. While an SD-WAN also has underlying physical infrastructure, it creates a virtual overlay that uses public internet transport.
Key Benefits Of SD-WAN Over Standard WAN
There are several benefits that SD-WAN offers over a standard WAN architecture.
1. Reduced Costs
MPLS can be expensive for long-distance connections since it requires specialized hardware, software and dedicated IT resources to set up and maintain the infrastructure. SD-WAN, on the other hand, uses the low-cost internet, which is available globally and leverages software-defined networking to harness and optimize existing resources—this reduces CapEx and OpEx expenses significantly. Acquiring and deploying SD-WAN hardware may incur some costs; however, the cost of installing and operating these devices is relatively insignificant in comparison to dedicated MPLS circuits.
2. Faster Performance
While MPLS comes with quality-of-service (QoS) guarantees, SD-WAN compensates for the occasional packet losses using dynamic path selection. In other words, SD-WAN optimizes traffic by selecting the most efficient route and intelligently steering away from poor connections.
3. Increased Flexibility And Scalability
SD-WAN delivers more flexibility because network connections, topology, applications and bandwidth can be defined, managed and dynamically adjusted from the software itself. SD-WAN is also quite scalable—one can easily add branches, applications and services without worrying about adding substantial underlying hardware (except for a single lightweight hardware or virtual appliance at each site or the network edge).
4. Centralized Management
In the case of standard WAN, hardware and devices need to be programmed directly via an on-box console instead of being managed centrally. In contrast, SD-WAN has a tool that enables centralized administration and policy management—eliminating the need to manage every piece of hardware or equipment individually.
5. Improved Security
Remote work poses several security risks to organizations. These risks are further exacerbated by cloud applications that employees use daily. SD-WAN provides deeper visibility and control of network activities, especially if part of a single-vendor SASE. This allows security professionals to proactively identify security threats and protect the network. SD-WAN allows organizations to set up virtual private networks (VPNs) for protected regions that are governed by specific cybersecurity policies. This type of network segmentation reduces the impact of cyberattacks and aids in faster recovery.
Making The Transition—Wisely
However, transitioning to any technology requires a deep evaluation of current infrastructure and needs as well as the limitations of the technology itself. SD-WAN appliances sit atop the underlying infrastructure, which means their performance and reliability depend heavily on the overall health of that infrastructure.
For instance, in the absence of a private backbone, using the public internet for ultra-long haul connections to remote areas will result in poor performance. Similarly, security is an add-on to SD-WAN, not a built-in feature. Options like a single-vendor SASE can address the need for reliable, private backbone and security features, but the key is to have a clear understanding of the required features and capabilities. In addition to evaluating current needs, companies can opt for pilot programs or deploying SD-WAN in specific branches to allow for testing and refinement before full-scale deployment.
Gartner estimates that 70% of enterprises will have implemented SD-WAN by 2026. A majority (60%) of new SD-WAN purchases will come as part of a single-vendor SASE procurement. If organizations run a cost-benefit analysis and calculate the pros and cons, they will realize that the SD-WAN framework is a worthy successor to standard WAN.
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