METHOD AND APPARATUS FOR PROCESSING CALLS ON A MULTIPROCESSOR COMMUNICATION SYSTEM
 The present invention generally relates to communications and, more particularly, to a method and apparatus for processing calls on a multiprocessor communication system.
BACKGROUND OF THE INVENTION
 In a communication system, call processing facilitates connectivity between two or more communication devices on a network. These communication devices include conventional phones, video-phones, or other types of devices that carry audio and/or video information. Initially, call processing uses a call setup process to allocate communication resources to be used by the communication devices when communicating over a network. For example, this may include allocating bandwidth and storage buffers on the system to be used by different communication devices to use during voice or data communication. A call tear-down process breaks the communication connection between the communication devices and reallocates the communication resources back to the system once the communication is completed.
 Some communication networks use a call processor (CP) to perform the call setup and call tear-down processes. On larger networks multiple CPs handle the call setup and tear down processes. These CPs use signaling to communicate with the communication devices during the call setup and call tear-down processes.
 In conventional systems CPs are statically associated with the particular communication devices throughout the call setup and tear down process. The association between a communication device and a CP remains constant even when call patterns change within the network. Unfortunately, calls often overload the network because several CPs become overloaded, even though other CPs are available to process calls. For example, increased communication activity on one part of the network may overload a single CP with call processing tasks while another CP on the network remains idle waiting for communication activity. Accordingly, it is desirable to implement methods and apparatus for processing communications on a multiprocessor network that prevent, or at least minimize the number of, processors that become overloaded.
SUMMARY OF THE INVENTION
 A method consistent with this invention, for use in a network having multiple, processors, of processing a call between communication devices includes selecting one of the multiple processors to setup the call when the call is requested, setting up the call using the selected processor, transferring information between the communication devices, and terminating the call upon receiving an appropriate request. Means for carrying out this method are also provided.
 An apparatus consistent with this invention for processing a call between communication devices over a network includes a plurality of processors, each including
memory containing instructions. The processors execute instructions and, when the call is requested, select one of the processors to set up the call, the selected one of the processors executing instructions thereby setting up the call. During the call, the processor transfers information between the communication devices. The plurality of processors also select one of the processors to terminate the call upon receiving an appropriate request.
 A computer program product consistent with this invention for execution by a processor capable of processing a call between communication devices over a network including multiple processors includes program code capable of selecting a processor to set up the call when the call is requested, setting up the call using the selected processor, transferring information between the communication devices, and selecting a processor to terminate the call when call termination is requested.
 A network consistent with this invention for use with communication devices for exchanging information over the network includes line cards operatively connected to the communication devices and the network to facilitate the exchange of information, and multiple call processors operatively connected to the network and the line cards, wherein each call processor is capable of determining which one of the multiple processors should be used to set up a call and which one of the multiple processors should be used to tear down the calls. In one embodiment, the determination of which processor should be used for setting up or tearing down calls is made based on relative activity levels of the processors.
 The above desires, other desires, features, and advantages of the present invention will be readily appreciated by one of ordinary skill in the art from the following detailed description of the preferred implementations when taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
 The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the principles of the invention.
 FIG. 1 is a network consistent with the invention;
 FIG. 2 is a block diagram of components in a call processor, consistent with the invention, having multiprocessor call setup, multiprocessor call tear-down and activity level table modules for communication over a network;
 FIG. 3 is a flow chart showing the overall steps of processing a call on a network consistent with the present invention;
 FIG. 4 is a flow chart indicating the steps, consistent with this invention, of setting up a call on a network;
 FIG. 5 is a flow chart illustrating the steps, consistent with this invention, of tearing down a call on a network;
 FIG. 6 is a flow chart showing the steps, consistent with this invention, of selecting a processor to process a call in a multiprocessor architecture; and
 FIG. 7 illustrates an activity level table indicating the load associated with processing calls on each of the multiple call processors.