Increasingly enterprises are considering a transition to a hybrid WAN environment. Many have already started the transition. The adoption of Software-Defined Wide Area Network (SD-WAN) technology over a hybrid WAN infrastructure allows enterprises to partially or fully offload traffic from traditional MPLS networks to broadband Internet access, with lower cost per bit.

In planning the transition to a hybrid WAN, however, one of the common questions we are asked by our customers is whether it is appropriate to move their Unified Communications (UC) applications to a broadband Internet — i.e. how confident are we to let Internet, a best effort service that is generally not as reliable as MPLS, take the load of UC traffic known to be vulnerable to: packet loss, latency and jitter? This will determine whether an expensive MPLS connection can be completely eliminated from branch office(s) which brings greater cost savings to enterprise.

The answer to this question will depend on the factors outlined below:

How critical is UC to your business? While some enterprises have successfully run their UC applications over the Internet, there is still no assurance that the UC service quality will be maintained in a connection which lacks end-to-end Quality of Service (QoS). If you cannot compromise on the quality of service for a given branch office, MPLS should still remain as the primary choice of transport.

Are your branch offices concentrated in the same region or are they distributed? If your office locations are limited to one region for example, the United States, there is less likelihood that your UC applications will suffer from Internet quality issues — given the shorter distance between locations and the general quality of Internet available in the local market. However, if your offices are distributed across multiple international and/or continental regions, there is higher chance that the UC packets will be affected by Internet quality issues.

Is your UC on-premises or cloud (UCaaS) based? For on-premises deployment, you typically have the flexibility of using MPLS and/or Internet for transport options. Some UCaaS services are primarily designed to be serviced over the top and hence it is best to consult with your service provider to determine the best options for your business.

Enterprise should consider solutions that are available in the market that will help to alleviate the impact of Internet quality issues on UC and other applications.

You could consider using Internet only as a means of access to the nearest MPLS node as opposed to using Internet for an end-to-end link. This effectively minimizes the use of Internet and allows UC packets to run over MPLS with guaranteed QoS on a greater portion of the link. This works well especially for site-to-site traffic that flows over greater distances. The critical point here is to work with the provider with an adequate distribution of gateways globally.

Another solution is to leverage the ‘Forward Error Correction’ mechanism that is provided from selected SD-WAN technology vendors. This allows the reconstruction of lost packets which can substantially increase the performance of low quality Internet links.

In summary, in pursuing the hybrid WAN initiative, enterprise must carefully assess their current environment and business needs, and the technology options available to best accommodate critical enterprise UC applications.