MPLS, SD-WAN Not an Either/Or Scenario

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Software-defined Wide Area Network (SD-WAN) technology is providing enterprises with greater flexibility and agility over WAN connectivity, but is being used to supplement rather than replace existing implementations of Multiprotocol Label Switching (MPLS) WAN circuits.

That may be a surprise to many who are wowed by the fast pace of SD-WAN adoption. “In the classic engineer’s formulation, ‘You can have it cheaper, faster, or better…pick two,’” writes John Burke, CIO and Principal Research Analyst - Nemertes Research. “From time to time new technology comes along and, by changing the basic assumptions underlying existing solutions, manages to be cheaper and faster and better all at once. SD-WAN promises to hit the trifecta.”

But, according to Nemertes survey data, nobody is rushing to shut off MPLS as they turn on SD-WAN. “Fully 78% of organizations deploying SD-WAN have no plan to completely drop MPLS from their WAN,” Burke reports. “However, most intend to reduce and restrict their use of it, if not immediately then over the next few years.”

No Appetite to Discard Traditional Backbone

MPLS provides the backbone for many enterprise data network architectures, primarily for its ability to manage services between major hubs, such as data centers. But it’s not as well suited for branch offices, particularly if a business is frequently opening or moving offices. In fact, Burke points out, the lead time for provisioning MPLS has increased over the past 8 years. Still, for a company currently relying on that technology, there’s virtually no appetite to discard it.

“Although it brings a lot of benefits to the table, SD-WAN still uses the public Internet to connect your sites,” points out Network World contributor Mike C. Smith. “And once your packets hit the public Internet, you will not be able to guarantee low levels of packet loss, latency and jitter: the killers of real-time applications.”

Compelling Hybrid Scenarios

Many network administrators are unwilling to accept performance compromises with key applications. What does light up their eyes, however, is the use of SD-WAN to supplement or off-load some of their MPLS requirements to shave costs, implement alternatives over time, and respond quickly to changing user needs. “The fact that MPLS doesn’t seem to be disappearing anytime soon sets the stage for a large number of the deployments SD-WAN is currently seeing — hybrid,” observes SDxCentral.

Rick Hubbard, of networking product management for AT&T Business, told participants at a LightReading conference that the discussion around WAN technology is not a case of MPLS or SD-WAN, but rather one of MPLS and SD-WAN. "What SD-WAN gives us the capability to do is a network with multiple types of technology at a single location," the publication reported, adding that “the location itself can be hybrid in addition to total hybridization of the network.”

Rohit Mehra, VP of network infrastructure at IDC, told FierceTelecom that “SD-WAN offers compelling value for its ability to optimize MPLS costs, simplify and automate WAN operations, improve application traffic management, and dynamically deliver on the cost and efficiency benefits associated with intelligent path selection. SD-WAN will be particularly relevant for enterprises that have adopted or are adopting hybrid cloud and especially those that are availing themselves of SaaS application services.”

To learn more about the coexistence of SD-WAN and traditional WANs, read this IDC white paper. For more information on SD-WAN click here.