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The Battle of Bandwidth: MPLS vs. SD-WAN


Multiprotocol Label Switching (MPLS) has been a great service for the last 25 years. But technology evolves. What may have once been considered a premier solution to meet market demands will run its course as needs and times change.

As a routing technique, MPLS applies a circuit-switched discipline to deliver packets and avoid packet loss over a distributed network. That means it is reliable and efficient at keeping traffic flowing. In addition, since the buyer leases the entire circuit, it is not shared with anyone else, making it inherently more secure. Most organizations with an MPLS network connect their locations and branch offices to a central data center, using a hub-and-spoke WAN model to connect the different points. Data travels to the data center to be processed and redistributed to the branch.

That approach worked well for decades. But that was before the Cloud, bandwidth hungry apps, broadband, software as a service (SaaS) and our culture’s wholesale reliance on the internet – all of which have diminished some of the distinct advantages of MPLS. Here, we look at the battle of bandwidth and compare MPLS to Software Defined Wide Area Networks (SD-WAN).

Insufficient Bandwidth

Because MPLS was designed for networks that depended on data centers, it simply is not well-suited for situations where branch or field office employees want or need direct access to the Cloud. Organizations with MPLS networks that have adopted Cloud applications must “backhaul” all traffic from their branches through their data center (or HQ) and on to the Cloud. Backhauling causes slower internet access due to the delay or latency associated with routing traffic over longer distances to the data center and then on to the Cloud service, leading to poor user experiences. When critical Cloud applications are involved, productivity also suffers.

The problem has been magnified in the last few years by the steady rise in video traffic. In 2018, Cisco predicted that video would account for 82% of all internet traffic by 2022. That was before the pandemic and the 70% spike in internet use in 2020; and before Zoom had over 300 million meeting participants per day on its videoconferencing platform.

Typical MPLS networks depend on T1 lines that are limited to only 1.5 Mbps service; the challenge here is that the standard T1 line is too small for bandwidth hungry apps and the growing number of users and devices. Since there’s no end in sight to these usage trends, organizations will likely find themselves playing a costly game of catch up as they strive to meet rising bandwidth demands by adding new T1 lines which may prove insufficient and not resolve performance issues.

Inescapable Costs

In addition to MPLS networks being inefficient when it comes to operating in a Cloud environment, they are also expensive compared with IP-based broadband deployments. Today it’s easier and much less expensive to add IP-based broadband than new private MPLS connections. Because MPLS is purchased as an entire leased line from a carrier, it is far more expensive than sending traffic over the public internet – especially in more remote areas where costs are dictated by circuit distance. Even with new services like 3, 5, and 10 Mbps Ethernet, the costs are still much higher than IP-based broadband.

If a network needs to be expanded geographically, there is also the added expense of infrastructure and the common delays associated with deployment. As organizations expand into new areas, they may find it difficult to find an MPLS service provider that can deliver coverage. For all of these reasons, it is not unusual for broadband to deliver cost savings of 60% to 70% when compared to T1 and other MPLS transport options.

SD-WAN as a Leading Alternative

With the advent of SD-WAN, there’s another option to meet the changing needs of distributed networks. SD-WAN is a virtualized WAN architecture that connects and extends networks over large geographical distances. SD-WAN can simplify branch or field office networking and assure optimal application performance and security protocol application, creating a network with more capacity and security than MPLS. In their 2020 WAN Market Survey Report, Gartner stated that SD-WAN is now “becoming the de facto option for new WAN edge sourcing initiatives.”

So what are the differences between the two? As noted, traditional MPLS networks rely on static physical links to connect remote or branch users to applications hosted in data centers via a hub-and-spoke design. Data flow is typically determined by a network engineer or administrator who writes rules and policies, often manually, for each router on the network ─ a process that can be time-consuming and prone to errors.

SD-WAN, on the other hand, uses software to control and manage network traffic from a central location with dynamic execution at every site. SD-WAN routes application traffic over the best path in real time. In the case of Cloud services like SaaS, SD-WAN can connect to internet- and Cloud-bound traffic directly from a branch, doing away with backhauling, and delivering improved user experiences. SD-WAN can also manage multiple types of connections, including MPLS, broadband, LTE and others, as well as support applications hosted in data centers, public and private Clouds, and SaaS services like, Workday, Office 365 and Dropbox.

The flexibility and scalability of SD-WAN enable an organization to either shift completely away from MPLS or to apply a hybrid approach, seeking the right mix of MPLS connections (for high-priority data center applications, for example), broadband (for high-bandwidth and internet-based applications), and even 4G LTE (and eventually 5G) wireless connections to meet each location’s needs. SD-WAN’s greatest strength might be its ability to leverage multiple broadband transports to connect field office locations securely, reliably, and cost-effectively to ensure users across the network have a consistent and high-performance experience. The result? Organizations with SD-WAN win the battle of bandwidth.

Thank you for reading part 1 of our MPLS vs. SD-WAN comparison. Part 2 will focus on the security aspects of the two networking approaches; highlight how security is integrated into SD-WAN; and how new frameworks, like the Secure Access Service Edge (SASE) are advancing security even further in this Cloud era.

For a different look at how SD-WAN works, watch this video from our colleagues at Hughes Europe. For more information about MPLS and SD-WAN, download our eBook here.