SD-WAN vs. VPN: A detailed comparison

What is an SD-WAN?

SD-WAN stands for software-defined wide area network. It is an advanced networking technology that helps businesses efficiently manage wide area networks. Organizations use SD-WAN solutions to seamlessly connect and oversee business applications, users, and data across several locations.

An SD-WAN uses a range of WAN connections — such as broadband internet, LTE, MPLS, and 4G/5G — to route network traffic between locations. It’s an excellent way to optimize communication between remote offices, even if they’re in different countries or continents.

An SD-WAN applies software-defined networking (SDN) principles, such as centralized network control and abstraction, to simplify network management. Centralized network control allows network administrators to manage all aspects of the network from one location (e.g., changing configurations across all company devices). The second principle, network abstraction, simplifies complex network details and presents them in a more user-friendly way.

Using an SD-WAN is best suited for organizations with multiple branch offices, remote locations, or distributed networks. It offers a flexible and scalable solution for businesses that need efficient and reliable network connectivity.

SD-WANs vs. VPNs

Before comparing an SD-WAN with a VPN, it’s important to reiterate that they are two distinct technologies that serve unique purposes.

An SD-WAN is an advanced networking solution that optimizes communications between different business locations. A business VPN, on the other hand, is a secure networking technology that gives employees secure access to the company’s internal resources from remote locations. Let’s compare SD-WANs and VPNs in terms of security, cost, performance, and scalability.

Security

Both SD-WANs and VPNs offer security benefits to businesses. However, a VPN is designed for security, while an SD-WAN’s primary purpose is optimizing and managing network traffic between several locations.

A VPN encrypts all outbound traffic, scrambling data to make it unreadable to unauthorized parties. It allows remote employees to securely connect to a business network while working from home or on the go.

A virtual private network also increases employee privacy by creating an encrypted VPN tunnel between the user’s device and the company network. This VPN tunnel makes it more difficult for malicious parties to intercept and eavesdrop on the data as it travels over the web.

An SD-WAN isn’t designed for network security — but some SD-WAN solutions may include security benefits (such as a site-to-site VPN connection and encryption).

SD-WAN providers may also allow businesses to secure the entire network with end-to-end encryption rather than establishing manual, individual VPN connections. Other built-in SD-WAN security measures may include integrated firewalls, traffic segmentation, threat detection, and mitigation.

Cost

The cost of each solution depends on several factors, such as the organization’s size, the number of sites or users, and the chosen provider.

VPN pricing is typically more straightforward and cost-effective than an SD-WAN. That’s because a VPN offers a simpler service, while an SD-WAN provides a more complex and comprehensive networking solution.

With an SD-WAN, companies typically have two options — a managed service provider (MSP) offering an SD-WAN solution, or building their own SD-WAN in-house. However, in-house implementation comes with a significant upfront cost and the future costs of replacing the aging infrastructure.

Performance

Let’s compare the performance of SD-WANs and VPNs by looking at three key performance areas — network speed, reliability, and user experience.

• Network speed. An SD-WAN uses dynamic path selection (i.e., intelligently and automatically choosing the most appropriate route) to optimize network performance. As a result, an SD-WAN can offer excellent network speeds and improved application functionality, especially for cloud-based services. Conversely, a VPN adds an extra layer of encryption to the data transmission process, which may slow down the connection. The slower speeds may be more noticeable in corporate networks where companies transmit data over long distances. However, modern VPN applications are more efficient, so they shouldn’t significantly affect the speed.
• Reliability. SD-WAN appliances use multiple network connections simultaneously, providing reliable network connectivity. If one connection fails or experiences issues, an SD-WAN automatically switches to another available connection to ensure the network functions properly. When configured correctly, a virtual private network (e.g., an IPSec VPN) is also a reliable networking solution. While older VPNs rely on a single network link, modern VPNs use multiple connections simultaneously, offering better performance and reliability.
• User experience. SD-WAN technology optimizes network traffic to improve how data flows over networks. It allocates bandwidth to prioritize critical apps (such as video conferencing), reduces network congestion, and ensures fast network speeds. Users can enjoy better application performance and smoother communication over the corporate network. VPN providers, whether B2B or B2C, also want to deliver the best experience to their users (otherwise, they might lose them to a competitor). Many VPN providers offer intuitive interfaces, helpful features, and a fast connection speed. Additionally, they ask for user feedback to continue improving in the areas they’re lacking.

Scalability

SD-WAN appliances are designed for large enterprises. Their flexibility means they can easily accommodate multiple branch locations, remote users, and cloud-based applications.

As the company and the network grows, an SD-WAN dynamically handles increasing traffic and adapts to the changing needs of the business. The centralized management and streamlined processes also make it easy to add new sites and users. This scalability is a huge advantage for organizations looking to expand their network infrastructure efficiently without compromising performance.

VPNs can also be tailored to the needs of growing businesses. Many VPN providers offer features and strategies that help incorporate VPN solutions into the infrastructure of an expanding business. Nonetheless, a VPN wasn’t originally designed for large enterprises, and it doesn’t offer as many benefits to larger corporations as an SD-WAN solution.

SD-WANs vs. MPLS

An SD-WAN and MPLS (multiprotocol label switching) are two distinct wide area networking approaches. While an SD-WAN uses software-defined technology, MPLS utilizes physical connections to establish private networks.

Compared to an SD-WAN, MPLS is a traditional technology. It offers a reliable, predictable, and secure data transmission — but lacks the dynamic flexibility of an SD-WAN. Dynamic path selection allows an SD-WAN to optimize traffic based on real-time conditions and business priorities, while MPLS requires manual configurations.

MPLS is typically more expensive than SD-WANs because it uses dedicated lines and has higher operational costs. Overall, an SD-WAN is a better choice for most modern businesses.

SD-WANs vs. WANs

Both SD-WANs and WANs (wide area network) are networking technologies that connect businesses over multiple locations.

Initially, companies used traditional WAN solutions to manage multiple office locations. However, WAN technologies were expensive and not great at adapting to new developments (like the emergence of cloud computing).

SD-WANs were created to address WANs’ limitations and meet modern businesses' evolving needs. They offer a more versatile network management approach than a simple WAN network.

Even though the technology is relatively new, SD-WAN adoption is growing rapidly as businesses become more mobile and remote work grows.