Software-defined WANs deliver clear benefits and have reached a maturity level that warrants consideration for customers with branch offices. However, enterprises must also weigh the challenges and have an accurate anticipation of SD-WAN advantages and disadvantages before they decide to adopt this technology.
Top SD-WAN challenges
Before venturing into this new technology, check out some of the top disadvantages of SD-WAN, and consider the possible effect to the network environment.
Cost. SD-WAN will increase costs in the near term like any new investment, but it can provide operational efficiency and savings in the long term as those deployment costs eventually are amortized. While the near-term, underlying WAN circuit costs may not immediately change, additional software licensing for this new layer of software may be necessary.
Technical skills. SD-WAN completely upends the WAN status quo and will require a lot of training for IT teams because of the new approach to WAN management. IT pros can't simply drop SD-WAN in and let the teams manage it. IT departments must also ensure they allocate enough money for their training budgets.
Security. WANs represent significant exposures because they are outward-facing and rely on transport outside the firewall. Deploying any new WAN technology can introduce unintended security issues. Additionally, vulnerabilities could now exist across both WAN layers.
Complexity. Typically, WAN connections are a single service from one company. SD-WAN adds an extra component on top, bringing an overlay to the existing WAN connection -- the underlay -- creating complexity.
Software. Software is more susceptible to errors, bugs and glitches, which is why, for years, WAN vendors preferred to hardcode functions into hardware for more stability. By moving to SD-WAN, customers will gain tremendous operational flexibility, but that comes at the expense of the peculiarities and limitations of software.
Troubleshooting. Because SD-WAN includes both an underlay and overlay in the WAN service -- and possibly from two different vendors -- troubleshooting becomes more complex. WAN issues then require two different places to investigate before zeroing in on the problem.
Advantages of SD-WAN
Despite these SD-WAN challenges, SD-WAN has clear benefits in each of these areas as well.
While SD-WAN deployment increases costs, businesses will be able to save money over time by optimizing their circuit costs and offsetting the initial deployment costs, ultimately leading to greater long-term savings.
Security, another common deployment concern, is one area where SD-WAN can better centralize and standardize security practices. While SD-WAN uses both an overlay and an underlay, SD-WAN's centralized controller can better maintain security throughout the whole network, instead of maintaining security at each individual endpoint.
The complexity that accompanies SD-WAN can eventually give way to a more streamlined operation, especially through automation and orchestration. Choosing the right managed service provider is one way to reduce complexity, as it can minimize the frustration that comes with provisioning, link procurement, configuration and policy creation. SD-WAN implementation alone will not make life easier, but a well-designed and well-implemented platform can reduce headaches over time.
The software benefit is less clear, as SD-WAN adds more layers and cost, but these higher licensing costs can offset costs in operational areas. Teams will likely find it more beneficial to view IT costs holistically rather than as siloed costs.
The training and development challenges that arise from SD-WAN also bring opportunities for more forward-thinking IT departments. This new technology brings a chance for businesses to train their staff on a cutting-edge technology, which improves technical and troubleshooting skills and bolsters the professional development for the whole department.
SD-WAN vs. MPLS WAN connections
While many businesses have relied on MPLS as the primary transport for their WAN connections, it is expensive and generally has lower bandwidth than other transports. SD-WAN use as an overlay can help optimize MPLS economics by directing only the most important data over the MPLS connection. Additionally, SD-WAN enables redundancy or load balancing through the addition of a second lower-cost transport, like broadband internet, ultimately reducing the overall transport cost.
SD-WAN provides far more flexibility with cellular connectivity, whether as a secondary transport for redundancy or as a primary transport for fully remote locations. The ability for SD-WAN to easily add cellular along with MPLS or broadband and direct the traffic for each link makes cellular connectivity a more viable transport for businesses.
When a primary transport is taken out by a backhoe or other unforeseen circumstance, SD-WAN provides a second transport to aid disaster recovery. In the case of natural disasters when all local infrastructure is down, SD-WAN cellular connections can help maintain business continuity by keeping a branch location online during prolonged interruptions.
MPLS services are complicated to deploy and configure. Making changes to MPLS are difficult and time-consuming, but SD-WANs enable self-managed services so the company itself is in control of changes and timelines instead of carriers.
When companies use cloud-based applications extensively, deeper insights into applications, users, usage and routing are especially valuable. Legacy connections, like MPLS, don't generally provide the depth of statistics that SD-WAN can provide.
How to overcome SD-WAN challenges
While SD-WAN has its disadvantages, IT teams shouldn't let them stand in the way of investigating or deploying this technology. These issues are important considerations in the planning process, and teams can balance the potential downsides against the business advantages to see if SD-WAN makes sense for the business. Armed with both the advantages and disadvantages, IT departments and business leaders can determine the best course of action in their SD-WAN plans.