Enterprise / Networking / WAN

SD-WAN vs. MPLS: Advantages and Disadvantages

Dennis Thankachan
Many business footprints expanded in 2020 for obvious, unanticipated reasons. Instead of all operations taking place under one roof or within a defined campus, work moved to remote locations over an expansive geographic area. Some grew to include logins from as far away as the home office of the employee with the longest commute. Although organizations were under pressure to enable remote work within a matter of weeks to keep operations running, reliable connections, high quality of service (QoS) and security had to remain priorities – or they quickly became pain points.

The two most popular options for wide area network management available to businesses, newly distributed or not, are software-defined wide area networks (SD-WANs) and multiprotocol label switching (MPLS). Although they’re not apples-to-apples comparable, IT leaders often view them as interchangeable alternatives. MPLS being the legacy, somewhat expensive, but unmatched QoS service, with SD-WAN as the cheaper, more flexible, newer option. Getting a handle on the “SD-WAN vs. MPLS” argument can be tricky, but it’s worth making the effort to understand the benefits and drawbacks of each technology.

SD-WAN vs. MPLS: What’s the Difference?

Both SD-WAN and MPLS connect users or local area networks (LANs) to enable communications over a wider area. MPLS technology runs on dedicated, physical infrastructure and uses proprietary hardware to route data in a predictable, secure manner. An SD-WAN, however, moves network functions from the physical to the virtual so that network infrastructure can be managed via software and the cloud. As a result, SD-WAN can steer traffic intelligently over the public internet, making use of regular broadband connectivity rather than expensive dedicated infrastructure.
Each has its own advantages and disadvantages, which may make choosing the optimal network management technology challenging. To focus on which type of network management is right for your business, start with this four-point side-by-side comparison of SD-WAN vs. MPLS.

Quality of Service (QoS)

MPLS: The labels used in MPLS technology isolate data packets and enable carriers to assign priorities to certain categories of traffic as they travel over private or dedicated leased lines. This groundwork supports a system with near 0 packet loss and the highest possible reliability. Carriers offering MPLS network management back it with 99.9%+ service level agreements (SLAs) to guarantee the users will have the speed, bandwidth, reliability and performance they promise.

SD-WAN: A software-defined system offers similar reliability and quality of service but leverages the public internet rather than a dedicated line. Therefore, service levels for data routed through the public internet are often not backed up by an SLA. This is fine for most use cases, but for instances where packet loss or bandwidth reliability is mission-critical, SD-WAN alone may not cut it.

Advantage: MPLS. Although MPLS can get pricey, the QoS is unmatched. Nothing beats an SLA-backed dedicated route!

MPLS: Because this network management technology is separate from the public internet, it is considered a secure transport mode, not vulnerable to certain types of cyberattacks, such as Denial of Service (DoS) where the system is flooded with traffic to the point that it’s incapacitated. Security solutions, however, are required to protect the network from unauthorized users gaining access, for example, by stealing a user’s login credentials. MPLS providers usually don’t provide those security solutions; they are the responsibility of the user.

SD-WAN: Different SD-WAN vendors offer different “flavors” of security options. Today, SD-WAN + SASE, an SD-WAN and cloud-based security package rolled into one, has become quite popular for companies whose WAN security postures are top-of-mind. SD-WAN allows users to build a multi-layered security strategy that includes firewalls, URL filtering, end-to-end encryption and more, controlled in an easy cloud-based network management tool.

Advantage: It depends. MPLS comes out-of-box as a more secure WAN solution, but requires some work to create a highly-configured, flexible security posture. SD-WAN has the potential to make security easily configurable and highly customizable, but this depends on the vendor and specific solution selected.

Cost and Scalability
MPLS: Depending on the types of data traveling on the network, bandwidth requirements can be high, especially for video applications or large file transfers. MPLS, which is priced per megabit, can get very expensive when bandwidth needs are high. Also, when the user needs to expand their network geographically, this requires an investment in additional infrastructure from the same carrier managing the rest of your MPLS network. Further, MPLS implementations can be slow and frustrating, as they require action from an ISP.

SD-WAN: With SD-WAN, the physical distance between endpoints doesn’t matter. The network can use any form of internet connectivity - regular broadband or even cellular service - to add links without changes to the business’ infrastructure. The ability to use different carriers and connectivity types also empowers users to optimize their costs, enabling them to route low priority traffic over less expensive network pathways. Moreover, SD-WAN makes it easier to build redundancy via multiple carriers.

Advantage: SD-WAN. No need to depend on a single carrier or form of connectivity means your WAN is (likely) cheaper and easier to scale. This is one of the main reasons people get excited about SD-WAN in the first place!

Ease of Management

MPLS: Because MPLS is carrier managed, the user has minimal responsibility or workload related to network management. That said, changes to routing protocol or general maintenance requires interactions with an ISP which can be slow and frustrating at times.

SD-WAN: SD-WAN requires active management from the user, but most vendors offer easy-to-use cloud-based applications that make network management a breeze. Further, managed SD-WAN solutions are available that take network management off your hands if that’s a preference. Most vendor applications make it easy to centrally manage your network, gain deep network visibility insights, and optimize the routing of traffic dynamically.

Advantage: SD-WAN. This one is less clear cut, but complete flexibility at your fingertips in a cloud-based management application is hard to beat. MPLS can be better if you’d prefer a carrier fully manages your WAN, but remember that managed SD-WAN is a reality too!

SD-WAN vs. MPLS: Is There a Clear Winner?

It’d be much easier to declare a simple winner here, but reality is unfortunately less clear cut. Both MPLS and SD-WAN continue to have a place in the industry depending on your use case and budget.

SD-WAN’s cost, scalability, and flexibility are driving transitions away from MPLS, and it’s often the choice for organizations with growing cloud and Software as a Service (SaaS) traffic requirements. The SD-WAN vendor may even accommodate direct connectivity to private or public clouds (e.g., Azure and AWS).

MPLS may be the better choice for organizations with strict connectivity and security requirements and for those that continue to use on-premises data centers and applications. If QoS is mission-critical to your organization and you’d like an SLA backing aspects of your service, MPLS is probably your best bet.

Also, remember that a business isn’t locked into one or the other. An organization with an SD-WAN can still route sensitive, real-time data on MPLS to ensure that priority information reaches its destination reliably.

The best choice when considering SD-WAN vs. MPLS is to match the network management strategy to the business’ unique needs.

If you’re interested in learning a bit more about specific SD-WAN vendors, check out our 2020 SD-WAN buyer guide.
If you’re looking to deploy SD-WAN or MPLS, configure your specific needs here and we can get you vendor specific actionable pricing and more for you to look through!

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