A dial number (DN) set is also called a dial plan. A DN set contains a set of numbers that are processed together. Only numbers, call prefixes, trunks, and routes that belong to the same DN set are processed. Two users can call each other only when the two users belong to the same DN set.
DN sets determine the home of users when associated with country codes and region codes, and determine the dial rules for users when associated with call prefixes. DN sets can be used to divide a physical network into multiple logical networks even in the same device, and are similar to virtual local area networks (VLANs) in a local area network (LAN).