The rise, fall, and rise again of SD-WAN
by Alan Earls Alan Earls on

SD-WAN has had a mixed reception over the years. A variety of factors have put this technology on a rockier market trajectory than some had expected. Now, with the rush to support Work- from Anywhere (WFA), it’s worthwhile to look at the strengths and weaknesses of SD-WAN and the role of end-to-end monitoring in making SD-WAN deployments better.

SD-WAN Rising

For serving distributed business infrastructure, SD-WAN rose with its promise of providing an alternative to setting up an owned and dedicated IP network or implementing Multiprotocol Label Switching (MPLS) data forwarding technology, which offers the potential advantage of connecting users over many different kinds of underlying infrastructure, (e.g. IP, Frame Relay, or Ethernet). By comparison, SD-WAN simplifies the process, potentially delivering a virtual WAN wherever there is an internet connection.

In some cases, this SD-WAN connectivity has been delivered as a service, in the expectation that this would further simplify adoption and deployment. But whether provided by a third party or managed by an organization for itself, critics have pointed to potential weaknesses in the SD-WAN premise, particularly for “traditional” applications where a centralized organization (with a few major facilities) wants cost-effective connectivity to a relatively finite collection of branch offices or outlying facilities.

In that schema, the dependence that SD-WAN has had on existing connectivity, which may have bandwidth and reliability problems, known or unknown, has often been seen as a problem, leading its stock to fall somewhat over the past few years.

Thus, while SD-WAN had been pitched as a potential panacea for many organizational networking challenges, a number of concerns and real-world experiences created plenty of doubters, taking the shine off of the SD-WAN star for many.

The fall

For example, reliance on available Internet connectivity was a key selling feature because it could get SD-WAN up and running quickly and at a competitive cost, but the results did not necessarily meet desired SLAs, according to critics.

Consider the challenges of VoIP. While that technology has a degree of tolerance for signal degradation or traffic collisions, it doesn’t take too many glitches to lead to serious and noticeable problems with service—and that quickly leads to unhappy users. If MPLS is available, sensitive communications such as VoIP can be rerouted from SD-WAN, but that’s a lot of extra trouble and potentially more expense. If that’s not an option, companies have found they often have to just muddle through and ask people to simply put up with it.

Rising again

In terms of interest in the technology, today, the SD-WAN picture is brighter thanks to changes wrought by the pandemic. Many organizations recognize they now must sustain secure, quality connectivity for a substantial portion of their workforce now operating in WFA mode. And they may need to do so indefinitely, as the positive benefits of WFA (combined with resistance to returning to traditional operations among many) forces a change in IT services delivery.

In this situation the appeal of SD-WAN (ease of set-up and operation and low cost) are again coming to the fore and would seem to better match the needs of a broadly distributed workforce. In other words, the ‘classic’ challenges of supporting, say 100 smaller facilities with 10-20 users, which might have been a typical use case in the past, are different from supporting thousands of individual WFA users. And in that new environment some of those SD-WAN challenges could be more acceptable. Afterall, in many cases the WFA connectivity of the past year has been far from ideal, so SD-WAN should represent an improvement.

However, potential performance and reliability issues remain.

If those overseeing SD-WAN operations aren’t able to collect detailed and continual performance measurements, they still won’t know what is causing problems. Efforts to reroute critical traffic will be problematic and troubles potentially chronic. What’s more, without comprehensive monitoring and diagnostics, operating vast WFA SD-WAN will be time-consuming and potentially futile.

That’s why any WFA planning and any attempt to increase reliance on SD-WAN should include active monitoring that can follow the underlying links and provide a true picture of the SD-WAN deployment and how it is holding up to traffic demands.

This can shine a bright light on communications and ensure that IT isn’t responding to problems by simply shooting in the dark. This can apply whether an organization is working with an ISP or handling all aspects of an SD-WAN.

Including end-user performance monitoring and measurement from the start is the only way to ensure that SD-WAN lives up to its potential and delivers what a company and a workforce needs in the era of WFA.


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Filed Under: Industry Insights

Tags: hybrid cloud , hybrid office , hybrid work , remote work , work from anywhere , work from home , enterprise cloud , enterprise IT , enterprise network , wide area network , software defined networking , WAN , SD WAN