In the days of traditional circuit switched telephony, companies were required to put a PBX on every site, so a large organization had many hundreds (if not thousands) of PBX switches. Advanced communications architectures now use shared IP-PBXs that are located in regional data centers. Calls are aggregated to the regional hub, rather than having a T1 trunk for every location to access the PSTN, saving considerable annual carrier costs.
Large enterprises or service providers will be interested in the benefits that advanced communications architectures can bring, particularly if the organization comprises multiple business units, operating across multiple countries with complex national and international trunking requirements.
