Compared to Multiprotocol Label Switching (MPLS), Software-Defined Wide Area Networks (SD-WAN) is said to be more cost-effective, secure, and resilient. Will SD-WAN replace MPLS?

Of the two, MPLS is still the king of low latency site-to-site data transfer; This makes MPLS appear hard to beat, especially considering most new technologies require the fastest data transfer rates possible. But it’s not all one way, as SD-WAN brings diversity and intelligent path selection into the mix.

This article explores the key differences between MPLS and SD-WAN plus delves deeper to see if it may not be a matter of simply choosing one over the other.

MPLS Overview

MPLS is a core network technology that managed WAN service providers (such as Securus Communications) employ to accelerate routing decisions and connect customer sites securely over a shared WAN. MPLS allows us to host multiple companies on the same platform while keeping each company’s traffic isolated from the others.

MPLS accomplishes this by assigning a label to every packet to speed routing decisions over large-scale networks. We use MPLS to create a secure Virtual Private Network (VPN) for each customer. Each VPN has a dedicated Virtual Routing and Forwarding (VRF) table that stores the routes of each site.

The benefit of MPLS is that it allows multiple end customers to securely traverse the Securus core network whilst keeping their traffic separated. Cost savings can be made on the core network infrastructure, and we pass that on to our clients.

Our MPLS network has a global reach, so businesses can seamlessly connect multiple sites, no matter their location, as if they are on one large dedicated WAN service.

SD-WAN Overview

SD-WAN Overview

SD-WAN is a cost-effective, software-driven WAN solution that our clients use for enhanced WAN connectivity between sites. It uses inexpensive, direct-to-the-internet broadband, 4G, LTE, and 5G WAN connectivity to connect local branch sites and data centres. 

The connections are encrypted, and traffic can be prioritised over numerous lines at each site as needed. SD-WAN allows companies to extend their networks over large distances and deliver critical services often cheaper than MPLS.

Securus uses a centralised management system to orchestrate traffic and ensure efficient use of the available bandwidth. SD-WAN can also monitor each WAN circuit’s load and delay and select direct traffic accordingly.

MPLS vs SD-WAN 

While there are several differences between SD-WAN and MPLS, the overall cost is one of the most debated topics. MPLS often uses more expensive dedicated circuits, while SD-WAN is a virtual overlay decoupled from physical links that can use cheaper direct-to-internet (DIA) lines.

Although SD-WAN initially has the upper hand over MPLS with cost as it provides optimised, multi-point connectivity that does not require costly dedicated circuits, we find the end solution pricing of these two technologies is about the same.

MPLS pricing has dropped to complete with SD-WAN in the past few years. Also, the additional hardware needed by SD-WAN for the centralised controller, more expensive branch site hardware, and extra technical support costs to run the more complex solution negates any cost savings gained from the DIA links compared to MPLS in our experience.

Additionally, MPLS often has the advantage of lower latency, and consistent bandwidth backed up by solid SLA’s surrounding uptime, packet loss, and latency. 

SD-WAN comes into its own for locations that optimised multi-point connectivity where dedicated circuits are not available. It uses distributed, private control points and data traffic exchange to provide users with secure access to needed services from any access point.

At Securus Communications, we offer you the best of both worlds. Our Hybrid SD-WAN solution uses both cheaper direct-to-internet DIA connectivity and high-performance MPLS lines that directly access our low latency high capacity core network. More about this fantastic solution next;

Hybrid SD-WAN

Hybrid SD-WAN

Given that MPLS and SD-WAN have distinct advantages, Securus Communications often recommends a hybrid MPLS design model for a mix of MPLS and SD-WAN specifically tailored on a per-customer basis for your precise needs. 

Hybrid SD-WAN uses a combination of traditional MPLS and direct-to-internet connectivity. Each physical site has one MPLS line and one direct-to-internet line in its most straightforward configuration.

Each link is monitored for its current usage, packet loss, latency, and errors in real-time. If one line fails, the remaining lines can take over the load. Furthermore, real-time services that rely on low latency use the MPLS line. Likewise, traffic bound for the public internet and web-hosted services use the direct-to-internet line.

This design model is efficient because latency-sensitive applications can utilise the MPLS platform rather than the public internet. Of course, internet performance is also enhanced because web traffic uses a direct-to-internet line.

A single MPLS line with a single direct-to-internet line for smaller businesses needing only a resilient yet straightforward solution is recommended. This solution incorporates SD-WAN technology to enable greater granularity of traffic flow. The traffic can temporarily travel along the MPLS line if the internet line fails until internet service is restored. Should the reverse happen, all traffic could use the direct-to-internet link.

For larger businesses needing additional bandwidth and increased resilience, a single or dual MPLS line with dual direct-to-internet lines is recommended. This solution works the same way as the previous, albeit with added lines to handle the additional applications and bandwidth.

Achieving Lower Latency

SD-WAN often seems the most cost advantageous as it uses cheaper direct-to-internet circuits; however, as discussed previously, a complete SD-WAN solution usually costs-in about the same as MPLS. Another trade-off from SD-WAN comes with poorer latency and response times. Some applications, especially real-time data transfer, voice and video applications, don’t perform as well over DIA links.

SD-WAN’s variance in response times can be significant enough to disrupt business applications and services that rely on consistent low latency. While companies may not notice a difference on a completely SD-WAN network if using low-latency sensitive services, the evolution of video meetings, voice over IP, and even the emerging metaverse will need consideration.

For global enterprises, MPLS offers consistently reduced latency and network stability. As discussed in the previous section, Securus Communications often recommend Hybrid SD-WAN to harness the benefits of both WAN technologies. 

Hybrid SD-WAN can allow high-performance or mission-critical services that operate in real-time can be directed over the MPLS line, while bulk downloads and low-quality sub-720p streaming can utilise the direct-to-internet line.

High Bandwidth Capacity

While MPLS reduces latency, MPLS and SD-WAN can supply the same bandwidth. SD-WAN, however, is more flexible in distributing bandwidth to critical need areas. 

MPLS provides a stable, fixed level of bandwidth. Initially, that seems like an advantage. Though, consider that network traffic has unpredictable performance requirements. To compensate, the organisation would need to lease enough MPLS capacity to handle the highest traffic load, which means expensive bandwidth goes unused much of the time.

SD-WAN has a different approach as it can recognise resource-hungry applications and adapt bandwidth accordingly. When needed, SD-WAN initiates multiple parallel direct-to-internet lines and provides granular load balancing between them. It can also prioritise latency-sensitive applications to receive the bandwidth they require.

Security Considerations

Security Considerations

While MPLS provides inherent L2 security, SD-WAN’s customisable security features offer better protection for IP data in transit. Out of the box, MPLS offers more robust security than SD-WAN unless the full suite of SD-WAN security features is used. MPLS provides a secure link between branch locations and the data centre via the provider’s internal backbone, and this is far more secure than any public internet connection.

However, MPLS security is not ironclad as it does not analyse the data it delivers. That responsibility falls to the customers’ firewalls and routers. As data travels through the MPLS connection, all traffic must be inspected for malware and other dangerous entities at some point along the path.

Many SD-WAN solutions require that security be added as an overlay solution such as SASE or SWG. Adding security is often more challenging than it needs to be when compared to MPLS.

Ease Of Provisioning

One of the more convenient features of SD-WAN is that the supplier handles the provisioning. However, take a closer look at the tasking, and you’ll see that even though the supplier may perform the provisioning for SD-WAN, the provisioning process is far more involved than MPLS.

You’ve likely heard that SD-WAN providers can provision a new site within minutes with Zero Touch Provisioning (ZTP), as compared to the time it takes to configure an MPLS connection. ZTP enables a business to provision a site without local configuration. 

Some SD-WAN devices can be shipped to the new site from the factory without the need for configuration. Once the ZTP device connects to the internet, it links to a centralised controller, receives verification against its serial number, downloads the configuration, and joins the overlay network.

Most of the time, MPLS is more of a manual provisioning process completed by your service provider. While it’s not as complex a task as SD-WAN, it does take an appropriate time to accomplish.

Conclusion

While it’s true that SD-WAN’s use of cheaper direct-to-internet circuits is more cost-effective than MPLS WAN connectivity, we find that factoring in the additional cost of centralised controllers and the elevated cost of SD-WAN branch devices makes both solutions cost-in at about the same.

Additionally, MPLS is not quite yet a replaceable technology. Low-latency services such as voice, video and the emerging metaverse will perform better over a high bandwidth low latency MPLS platform that Securus Communications offers.

Will SD-WAN replace MPLS? In our opinion, no. For the most complete and efficient network solution, consider our Hybrid SD-WAN solution for a blend of MPLS and SD-WAN. The two complement one another to create an optimum performance at a cost-effective price.

If you would like to understand more about the low latency WAN, SD-WAN, Edge, Fog and Cloud solutions that Securus Communications has available and how they can help your business, please don’t hesitate to get in touch.

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