Abstract: A telecommunications system having a software dispatcher is provided for delivering messages between dispatcher clients, i.e., software subsystems that may be in the same process, a different process, or on a different machine. The dispatcher manages a pool of threads to balance the workload. The dispatcher can process both synchronous and asynchronous messages by dispatching the message to all registered subsystems in order of their registered priority.

Abstract: A communication system, such as an H.323 system, in which a gatekeeper (108) may support a plurality of virtual private networks or virtual domains. Endpoints (102a, 102b, 106) are provided with communication domain identifiers (CDI) which identify the endpoints' domain. The CDI is provided during call setup and used during address resolution. In particular, H.323 endpoints according to the present invention are provided with a control layer which provides a communication domain identification (CDI) assigned to a user during call setup or other situations in which it is desirable to have domain-restricted functionality. In the call setup embodiment, the CDI may be used, during the address resolution phase of the H.323 direct signaling mode, to determine whether the call is to a user at another extension of the same company. In the direct signaling mode, the communication domain identification control layer accesses a local database to make this determination.

Abstract: A system and method is presented for providing a ringback tone at the initiating end of a call while substantially reducing bandwidth usage. The initiating end initiates a call through a network. The receiving end of the call responds by transmitting an alerting message containing information on the characterization of a ringback tone to the initiating end of the call. At the initiating end of the call, the proper ringback tone is determined based on this information, and a ringback tone is generated. When the call is picked up at the receiving end, a transmission to the initiating end alerts the initiating end to cease the ringback tone. Silence suppression may be used at the receiving end to prevent the transmission of an audio stream before the terminal (e.g., a phone) is picked at the receiving end.

Abstract: A telecommunications system having a software dispatcher is provided for delivering messages between dispatcher clients, i.e., software subsystems that may be in the same process, a different process, or on a different machine. The dispatcher manages a pool of threads to balance the workload. The dispatcher can process both synchronous and asynchronous messages by dispatching the message to all registered subsystems in order of their registered priority.