Systems and methods for routing an incoming service request to one of a plurality of pod units are described. A communication system can be provided that includes a plurality of pods each having a first pod serving a first subset of user accounts associated with a hosted PBX system. The first pod can include a first pod unit in a first data center and a second pod unit in a second data center. A global user directory (GUD) can be used to store a plurality of user keys that are mapped to the plurality of pods. A router can be provided to identify a user key from an incoming service request, query the GUD to identify the first pod as being associated with the user key, and route the incoming service request to one of the first and second pod units.