By facilitating the use of inexpensive public Internet connections in the wide area network, software-defined WAN (SD-WAN) presents a clear threat to service providers that make money by leasing expensive MPLS lines to enterprises. Some providers, however, seem prepared to meet that threat by embracing it. Verizon, Singtel and Talco, for example, now offer managed SD-WAN services in an apparent move to recapture business they might otherwise lose as software-defined WAN continues to erode the MPLS market.
The rise of software-defined WAN
In the age of Office 365 and Salesforce, many enterprises ask, "Why are we still paying so much for our MPLS WAN?" MPLS has been the workhorse of enterprise WANs for many years now, providing the large middle-tier of the standard three-tier architecture, bookended by Carrier Ethernet on one side (typically for data center interconnects) and by site-to-site Internet virtual private networks on the other end (for sites that are too hard or too costly to reach with MPLS).
Of course, the rise of reliable and low cost-per-Mbps broadband Internet has disrupted the conditions under which that model evolved. More than 70% of organizations with WANs have Internet-only sites as of 2015. Among those organizations, an average of 28% of a company's total sites have Internet-only connectivity -- a figure that is growing as MPLS tiers continue to shrink.
With a rising tide of Internet-connected branch offices to lift them, software-defined WAN vendors have emerged with the proposition that they can help replace some or all MPLS connections in the WAN with Internet links.
The main driver in most organizations deploying SD-WAN is cost reduction by supplementing or replacing MPLS links with commodity broadband connectivity. This can reduce cost-per-Mbps of bandwidth by 90% or more, and can allow IT to meet pent-up demands for huge bandwidth increases that MPLS costs often made prohibitively expensive.
Carriers respond with managed software-defined WAN
As enterprises cap, tighten or drop MPLS spending, carrier MPLS services will suffer.
In response, several carriers now offer managed SD-WAN services. These offerings can look a lot like regular managed router services, except that they freely incorporate Internet links for connectivity among internal sites.
These services allow the enterprise all the functional flexibility and most of the cost savings of an SD-WAN environment, while minimizing the headache of managing infrastructure and connectivity. A managed service also should make the transition from MPLS-only to SD-WAN smoother if the carrier in question is the current MPLS provider. And if the carrier is the incumbent, shifting to a different service within the provider's portfolio means no "new vendor" overhead and the continuation of an existing working relationship around support and billing.
For the carriers, the advantages are slightly different. Managed software-defined WAN gives these carriers a new approach to the WAN services space and they can manage the infrastructure at a lower internal cost. More importantly, managed SD-WAN gives them a way to recapture business they could otherwise expect to lose, and to provide a higher level of function at a lower cost. The ability to better match actual WAN functions to specific enterprise needs should make the relationship more "sticky" in the long term.
So, the combination of technical, functional and economic factors at work in the software-defined WAN space make managed SD-WAN services a pairing with obvious benefits -- both to providers and enterprises. Any enterprise looking to adopt SD-WAN should review the available managed options.
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