Abstract: Attribute based communications system include a set of communication units associated with a unique network identifier in a communication network having a switch, a registration center, and a registration database. Users establish user attribute records in the registration database for correlating attributes with network identifier of the user communication unit. Users establish communication links between each other by referencing attributes of the target user rather than the network identifiers of the target user communication unit. The system relates attribute based communication request messages with the registration database to derive the network identifiers for the communication units.