A feature of modern SD-WAN technology is the ability for branch locations to build dynamic tunnels to each other for taking the shortest WAN path to circumvent transiting a central hub. This optimizes VoIP and data transfer between branches for the duration of the session and then tunnels are torn down automatically to save on processing resources. SD-WAN vendors often price their hardware and software licensing based on tiered models to handle processing the number of tunnels needed for the environment. Because of this, it is important to choose the most cost effective model for the needs of the particular hub/branch locations. Though many perform due diligence to appropriately size and license correctly, there can be some variables that throw a wrench in the works.