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Why SD-WAN doesn't mean the end of MPLS connections

Many organizations are opting to keep their MPLS connections, even after deploying SD-WAN, defying predictions of the death of MPLS with SD-WAN's rise -- at least for some circuits.

About 21% of organizations are deploying some flavor of software-defined WAN, according to a Nemertes Research...

2017 survey. These organizations have mostly been lured by twin promises: First, SD-WAN will deliver a better WAN that is more reliable, resilient and high-performing; and, second, SD-WAN will also deliver a less expensive WAN -- at least on a cost-per-megabits-per-second basis. Does this mean enterprises will be ditching their MPLS connections? Not really.

The results of SD-WAN deployment have been gratifying for most early adopters. Many began their deployments in their most troublesome WAN locations: sites with the poorest connectivity quality or with the fastest-growing demands, or a combination of the two. They added SD-WAN to these locations, using it to manage not just their existing primary WAN link, which is usually an MPLS connection, but also an existing or new secondary -- usually internet -- link. Since migrating to SD-WAN, these organizations have seen enormous reductions in WAN service outages and WAN troubleshooting tickets and time.

Note that reduced service disruption and IT overhead are happening in spite of -- not in the absence of -- ongoing problems with individual links. Outright link failures continue to happen, as do more insidious brownouts, during which service is significantly degraded without ever actually failing. Thanks to SD-WAN services they have in place, network staff can know about these problems sooner and better understand the nature of the problems.

In some cases, organizations are even able to provide their carriers with important troubleshooting data. But SD-WAN's transparent traffic failover from bad links to good, coupled with prioritization and bandwidth management, have made link failures nonevents for end users. Without service interruption, IT spends less time -- and adrenaline -- resolving individual, usually transient, connectivity problems.

Are organizations dropping MPLS for SD-WAN?

The promise of a less expensive WAN

At this point, 60% of organizations say they will make no changes in their MPLS deployments as a result of layering on SD-WAN.

As for the promise of cheaper SD-WAN bandwidth, organizations are getting that, too -- with the significant caveat that they are not eliminating MPLS connections. At this point, 60% of organizations say they will make no changes in their MPLS deployments as a result of layering on SD-WAN. Basically, they continue to see MPLS as the backbone of the mission-critical WAN -- but it's improved and expanded by SD-WAN.

Of the rest, just over 20% say that they have capped their WAN spending, and nearly 20% say they will reduce number of sites using MPLS connections. None of the organizations said they will eliminate MPLS connections in the next few years. In 2016, the few who said they did intend to drop MPLS put their plans to do so at least five to 10 years out.

So, those who can't see the logic in dropping MPLS connections or even in significantly reducing their use of it -- or who simply have no confidence in the alternatives -- should take heart. Those companies may not be able to reduce current WAN services spending much, but they can certainly bring down future WAN costs by reducing the cost of growth through judicious use of broadband. They can also bring down the operational costs of WAN management while improving services to the business. This can all happen while keeping a technology they know, trust and value at the core of the WAN.

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This was last published in June 2017

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