| 摘要 |
In a broadband switching system for the switching of asynchronously transferred cells of data, a dynamic bandwidth controller (DBC) controls the application of data cells to an input port of the system, the data cells being supplied by a number of transmitting end-systems. When an end-system begins transmitting data cells, the DBC detects the presence of incoming cells and requests bandwidth from a connection admission control (CAC) forming part of the system. The switching system stores a table associating a number of signal sources connected to the ingress with respective predetermined transmission bandwidths and, preferably also, maximum delay times. When arrival of cells from one of the sources at the input port is detected, the DBC sends a request signal for the relevant predetermined bandwith to the CAC and delays transmission of the cells until at least the predetermined bandwidth is allocated. This delay is typically effected by sending a cell rate indicator signal back to the input port for placing the source in a halt mode. If no allocation of bandwidth has occurred before the respective maximum delay time, bandwidth is allocated by robbing bandwidth from other signal sources.
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