September 1979 | NTIA Technical Report TR-79-26

Switch Element Capacities in Access Area Digital Switching Systems

Robert F. Linfield; Martin Nesenbergs

Abstract: The capacity of a digital circuit switching system is defined in terms of its four major elements: the traffic offered by the interface element, the maximum traffic carried by the switch matrix, the maximum number of call attempts handled by the control processor, and the maximum number of calls handled by the signaling elements. These element capacities may be engineered for the expected traffic (e.g., call attempts and holding times), the performance objectives (e.g., blocking probabilities and tolerable delays), the processor capabilities (e.g., speeds, memory sizes, service features), and the signaling techniques (e.g., common channel or per–channel signaling). In a properly engineered system, the interrelations between the capacity of all elements should be considered. This report discusses such interrelationships and characterizes representative switch configurations on the basis of the four major elements. The results obtained have applications in developing non–tactical networks for military access areas where the communications profile is known. This is demonstrated for Ft. Monmouth and its environs. Estimates of traffic statistics and switching requirements are made with the aid of available Ft. Monmouth terminal density profiles.

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Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

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