Alchemy Blog

SD Wan: A Pragmatic Perspective

Software Defined Wide Area Networks (SDWAN) have been around for a while now so most people understand the basics of what the technology is expected to deliver to the market. Unfortunately, between the initial release of SDWAN and now, there have been a lot of marketing initiatives that have blurred the reality of what can actually be expected from this technology. Starting this week, I will publish several blogs addressing different aspects of SDWAN so I thought addressing the decidedly non-technical issue of cost would be a good place to start.

The initial marketing of SDWAN reducing Wide Area Network (WAN) costs was important to attract attention from potential early adopters. However, quantifying what that cost actually is has not always easy to understand but could be looked at from two easily understood perspectives:

  1. Can SDWAN reduce Cost?
    • Yes and no. SDWAN can reduce cost, but you have to put your trust in the Services Level Agreement (SLA) that SDWAN brings to the table. Enterprise companies tied to Multi-Protocol Label Switching (MPLS) contracts are in a somewhat intractable position. The difficulty being that if you are still using MPLS as part of your SDWAN deployment, and then you have to buy SDWAN hardware your Return-On-Investment (ROI) will likely take much longer to realize. Many of the enterprises we run across are not willing to take that jump to all public infrastructure.
    • Fortunately, things have improved with public and business class connectivity. Internet, Loss, Latency, and Jitter issues have improved in the last 5 years, although those improvements are varied when used in conjunction with an alternative SDWAN overlay. Additionally, the growing presence of fiber is having an impact and has been on the upswing recently with up to 25% coverage in the United States having connectivity capacities up to 1 gig in those coverage areas.
  1. There is a lot of potential for SDWAN to replace many of the differentiated services, as well as the SLA requirements for the MPLS. Below is a chart exemplifying the savings and ROI for a mixed MPLS and Public Circuit offering on a 4-year cost model.

Each branch in this example represents a regional site with a primary and backup MPLS circuit. Adding SDWAN eliminates the secondary MPLS and adds public circuit access with increased bandwidth. In this case, the ROI is realized in 18 months. These costs do not reflect the fact that with increased capacity from the public infrastructure, MPLS can be right-sized and those costs can be further reduced.

Administration and Support

SDWAN vendors have refined the issues of installation, configuration, and integration into existing environments as an overlay. SDWAN functions happen transparently, many times requiring minimal information to properly replicate routing and application forwarding for Quality of Service (QoS), and other differentiated services for application management. To ensure SLA compliance, some SDWAN vendors can also add circuit monitoring functionality for system states all the way down to a packet by packet basis.

By monitoring on the packet level, the data provides a high-resolution view on that state so that as the state changes the sensing response happens quickly so any failover would happen based on the application requirements & feedback on the error. In this situation, the system administrator would be notified immediately of the condition change which means that troubleshooting a failure issue is no longer a matter of sorting through data from various monitoring tools looking for an anomaly that caused a backup failure or a missed Recovery Time Objective (RTO). It is difficult to put an exact dollar value on an always up WAN, but as a long-time administrator of WAN networks, I would label it invaluable and a requirement for any network upgrade plan.

In summary, SDWAN has at this point, gone from a new and unproven technology to becoming a mainstream topic in any conversation around performance and value. Offerings from Citrix, VeloCloud, Aryaka and BigLeaf, all have features that when measured against the requirements of the modern enterprise can bring immediate benefits. Our advice is that you make the time to take a pragmatic approach to review & select the best solution for your environment.