What Is SD-WAN, How Does It Work, and What Are Its Limitations?
SD-WANs (Software-Defined Wide Area Networks) have been in wide-scale use for several years now, and their adoption has accelerated in recent years. The first SD-WAN products were introduced around 2013, but it took a few years for the technology to mature and gain widespread acceptance.
By 2018, SD-WAN had become a major trend in the networking industry, and many organizations were deploying SD-WAN solutions to simplify their network infrastructure and improve application performance. According to a report by IDC, the worldwide SD-WAN infrastructure market reached $4.5 billion in 2020, representing a dramatic 45.5% increase from the previous year.
But within SD-WAN solutions for organizations, there are critical differences—particularly for organizations that operate globally. To optimize SD-WAN for business performance, organizations must have a clear understanding of their connectivity priorities, including factors such as security and data privacy needs, salient cloud applications, centralized configuration, and global traffic that must be supported over the long haul.
This article covers the key points of interest for successfully implementing an SD-WAN solution, as well as complementary solutions to consider when SD-WAN alone is not enough.
What is SD-WAN?
SD-WAN is a technology that allows for the centralized management and control of a wide area network using software. In traditional WANs, network devices such as routers and switches are typically managed manually, making the process time-consuming and prone to errors. SD-WAN, however, uses software to manage network traffic and route it intelligently over multiple network links such as broadband, LTE, or MPLS. Depending on the needs of the application, this helps to improve application performance, reduce costs, and enhance security.
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SD-WAN is becoming increasingly important in the networking industry for businesses of all sizes because it offers greater agility, flexibility, and security in adjusting networks to meet changing business needs.
According to its vendors, SD-WAN also reduces costs by utilizing less expensive internet links, while maintaining the same or improved levels of performance and reliability as more expensive dedicated circuits. This is based on the assumption that most networking issues are at the last mile, and that being able to select between different last-mile connectivity options is the right solution. When this is not the case, complementary SD-WAN solutions for the long haul may be required.
What Is Long-Haul Connectivity?
Long-haul connectivity refers to the ability to maintain high-speed, reliable communication even over long distances, with minimal loss of signal quality or data integrity.
Key Features Of SD-WAN
SD-WAN’s smart combination of core key features makes it highly efficient.
A centralized management console enables SD-WAN administrators to configure and manage the entire network from a single location. Since SD-WAN is highly scalable, it can be easily deployed across multiple locations, making it ideal for organizations with distributed workforces or multiple branches.
Dynamic path selection automatically selects the best path for each application based on network conditions to reduce downtime, while application-aware routing allows for intelligent routing decisions based on the specific requirements of each application to optimize performance and reliability.
SD-WAN also supports Quality of Service (QoS) policies that enable network administrators to prioritize traffic so that critical applications receive the necessary bandwidth and resources.
Finally, SD-WAN may provide advanced security features such as encryption, authentication, and access control, which helps to protect the network from threats. However, it is important to assess the specific security capabilities among different solution providers.
Types of SD-WAN
SD-WAN presents diverse ways of deploying and organizing networks to suit different business needs. There are various deployment strategies like installing SD-WAN hardware on-site, using cloud-based services, or subscribing to managed SD-WAN services.
Additionally, SD-WAN architecture can be classified into overlay, underlay, or hybrid models, each with its own benefits in terms of simplicity, integration, and flexibility. Understanding these options helps businesses make informed choices about how to structure and manage their networks effectively.
Understanding SD-WAN architecture
The basic architecture of SD-WAN involves a centralized management system that controls network traffic, security, and performance across multiple network connections. The system uses software to create an overlay network that abstracts the underlying network hardware and connects different sites and devices.
SD-WAN architecture typically consists of the following components:
- SD-WAN Edge Devices: These are physical or virtual devices deployed at the edge of the network, typically at branch offices or remote locations. They are responsible for establishing and maintaining secure connections to the SD-WAN network.
- SD-WAN Controllers: These are centralized management systems that control the SD-WAN network. They are responsible for configuring and managing the network, including policies for traffic routing, QoS, and security.
- Underlay Network: This is the underlying physical or virtual network infrastructure that carries SD-WAN traffic. It can consist of various types of connections, including MPLS, broadband internet, cellular, and satellite.
- Overlay Network: This is a logical network that runs on top of the underlay network. It is created by SD-WAN edge devices and controllers and provides an abstracted view of the underlying network. The overlay network can optimize traffic flow, balance loads, and provide security.
Understanding SD-WAN deployment
SD-WAN deployment typically falls into three basic categories: on-premises, cloud-based, and SD-WAN as-a-Service (SDWaaS).
On-premises SD-WAN involves the installation and management of SD-WAN hardware and software within an organization’s premises. This traditional model requires procurement and maintenance of hardware, offering greater control and customization over network management.
Cloud-based SD-WAN, on the other hand, delivers SD-WAN functionality through a cloud-based service provider. It eliminates the need for on-premises hardware, providing scalability and flexibility, particularly suitable for organizations with distributed locations.
SD-WAN as-a-Service (SDWaaS) offers a fully managed solution by a third-party provider, available as a subscription-based service. This model ensures rapid deployment and scalability without upfront hardware costs, making it an attractive option for organizations seeking a cost-effective and low-maintenance SD-WAN solution.
How SD-WAN differs from traditional WAN (and why it’s better)
Traditional WAN (Wide Area Network) refers to the method of connecting multiple branches using leased lines, multiprotocol label switching (MPLS) or other dedicated connections. SD-WAN is designed to address the challenges of traditional WANs by providing better control, security, and visibility over network traffic, as well as improved application performance and availability.
For example, in a traditional WAN the network is controlled by the service provider, and any changes to the network, such as adding or removing a branch, require the provider’s involvement. In contrast, SD-WAN gives network control directly to the enterprise.
SD-WAN also provides centralized management and visibility, allowing IT teams to manage the entire network from a single interface. With a traditional WAN, you’d need separate management for each branch location.
And since traditional WANs do not have the app-aware routing capabilities of SD-WAN, they are more prone to low or inconsistent application performance. These are all significant hassles that negatively affect an organization’s performance and impede digital transformation.
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Common use cases for SD-WAN
One of the most popular use cases for SD-WAN is to connect branch offices to the corporate network, providing a secure and optimized connection for remote workers. SD-WAN helps manage traffic and prioritize critical applications so remote workers have a consistent and high-quality experience. SD-WAN also helps manage traffic between different branch locations, ensuring that applications receive the necessary bandwidth and that security policies are enforced.
Another common use case for SD-WAN is to manage multiple cloud services, such as Amazon Web Services, Microsoft Azure, and Google Cloud Platform. SD-WAN can help organizations connect and manage traffic between these different cloud providers, as well as between the cloud and on-premises data centers.
What makes one SD-WAN solution better than another and what are the limitations of SD-WAN?
There are objective differences in quality and performance among SD-WAN solutions. The level of vendor support, which may include customer service, technical support, and training, can differ significantly and should be a key selection factor. So, too, should the level of management and monitoring, as these will impact the ease of use and maintenance in the long run.
Ultimately, much will depend on an organization’s specific needs. Not every organization requires the most powerful solution, but for those who do, the differences can be critical. These include:
- Different deployment options, such as on-premise or cloud-based
- Different choices of network architecture, which can include hub-and-spoke, full mesh, or partial mesh, depending on requirements for cost, performance, and complexity
- And differences in scalability, which are determined by factors like the number of locations to be connected, the volume of traffic, and the growth projections of the organization.
Generally speaking, organizations that operate globally, with branches in different geolocations, will need more robust SD-WAN solutions. They may even require solutions that are complementary to SD-WAN, in order to optimize connectivity over the long haul.
Global network connectivity platforms such as Teridion use AI-powered route detection to dynamically find the fastest and most stable routes while in transit to ensure fast, reliable performance in any location and with any edge device. As an overlay network, Teridion has the agility to utilize the internet when it performs optimally, but once it detects that performance has dropped below the SLA threshold, it has full control to re-route traffic. Comparatively, SD-WAN can detect that there is an issue, but can’t fix it. SD-WAN is dependent on the best efforts of the internet – and can only control the exit point from which the traffic will reach its destination, such as a private lines, internet, or DIA.
The future of SD-WAN is bright
As businesses increasingly rely on cloud services and distributed workforce models, the need for a more flexible, secure, and cost-effective networking solution has become paramount. SD-WAN provides all of these benefits, as well as the ability to prioritize and optimize traffic flows according to business policies and application requirements.
Moreover, SD-WAN solutions are constantly evolving, and new features and capabilities are being added regularly. For example, we can expect to see more advanced security features integrated into SD-WAN solutions, such as advanced threat protection and secure access service edge (SASE) capabilities.
As the technology matures and becomes more standardized, we’re likely to see more interoperability between different vendors’ SD-WAN solutions, making it easier for businesses to adopt and manage multi-vendor networks. Global enterprises can also expect powerful SD-WAN enhancements that are specifically designed to optimize traffic over the long-haul so that international teams can communicate more efficiently.
Overall, the future of SD-WAN is bright, and we can expect to see continued growth and innovation in this space in the coming years.
Now global teams can communicate seamlessly, with optimized long-haul connectivity.
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