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Will MPLS Ever Go Away?

Multiprotocol Label Switching (MPLS) is one of the bellweather technologies of the modern Internet. MPLS serves as a leased-line circuit options for businesses looking for dedicated links between sites that are backed with service-level agreements (SLAs) from well-known providers like Verizon and AT&T.

MPLS has been a great technology for years. It’s been a way for businesses with multiple sites to connect across large geographic areas. But MPLS isn’t without drawbacks. It’s expensive. Most MPLS deployments require a significant investment of equipment to get up and running. And the contract price for the circuits isn’t cheap either. Providing dedicated traffic pathways costs a lot of money on a monthly and yearly basis. And if those SLAs aren’t met properly, the investment takes on a whole new level of expense: that of time spent troubleshooting down circuits and coordinating with technical support to fix issues.

Enter Software Defined WAN (SD-WAN). There are a multitude of benefits that come from using SD-WAN devices in your network. Application identification, cloud on-ramp, and ease-of-installation are just a few. But a huge one is the ability to take multiple circuit types and add them to a device that then chooses the best way to utilize the links for traffic. Now, instead of having a primary MPLS link and a backup broadband link that sits with no utilization, you can do more. You can now have MPLS and broadband each taking a portion of the traffic and then have a 4G/LTE backup link available for failover in the event that one of those links goes down. You can also measure how responsive those links are for day-to-day use. This is especially important to ensure that the SLAs are met on those expensive MPLS links.

The Need For MPLS

But will MPLS ever really go away? As much as we might like to get rid of expensive dedicated circuits and go with broadband and 4G/LTE, I think MPLS is here to stay. Even with SD-WAN helping us multiplex the circuits and get more value from them through proper utilization the fact is that MPLS has important uses. One is in the real of voice over IP (VoIP). VoIP calls prefer pathways with low latency and little variable delay. As great at broadband circuits are they are also very prone to delay. For VoIP calls between sites MPLS is still preferred. SD-WAN helps mitigate the time between failover from MPLS to backup links, which means that calls are less likely to drop in-progress if a switchover happens. But MPLS is still the preferred circuit type for these calls.

Additionally, SD-WAN still has a huge benefit for areas where broadband could be impacted on a large scale by outages. You may ask yourself “When could you possibly have your broadband circuits impacted?” The answer to this question could be China. When SD-WAN appliances are used in remote offices, they build tunnels between appliances for secure data transfer. Those tunnels use IPSec encryption. Today, the Chinese authorities do not block IPSec tunnels at their border firewall that inspects all Internet traffic coming in and out of the country. But what if that policy changes in the future? What would happen if your branch office suddenly drops offline because you can’t establish a connection through a firewall you don’t control?

The answer is MPLS. MPLS circuits can maintain a connection through private networks and ensure that your branch office stays online. Because MPLS is not consumer grade, it is often handled differently by regulatory agencies. MPLS circuits would allow branch offices in countries with restrictions to stay online should those restrictions impact broadband circuits.

MPLS is a technology that offers advantages to customers that want to use it. SD-WAN is teaching us that MPLS isn’t the magical solution that it was always sold as, however. Instead, MPLS is a piece of the connectivity puzzle. You need a good SD-WAN solution that allows you to build out each of the three prongs of connectivity – MPLS, Broadband, and 4G/LTE. Each has an important role to play and can offer advantages for specific technologies, like VoIP. Ignoring one means cutting off a portion of your capabilities. And no matter how much people try to sell us on the idea, there are some technologies that are never truly going to go away.

About the author

Tom Hollingsworth

Tom Hollingsworth is a networking professional, blogger, and speaker on advanced technology topics. He is also an organizer for networking and wireless for Tech Field Day.  His blog can be found at

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