| 摘要 |
An ATM system transmits different types of cells (data, forward resource management (RM) and backward RM) from station A through switch(es) to station B. Different fields in an Available Bit Rate (ABR) table provide controls over the rate of such cell transmissions. First particular field values in such table control the selection of successive ones of cell decision blocks which determine the type of cell to be transmitted. Second particular field values in such table control the selection of one of a plurality of entries in an exponent table which also provides other parameter values controlling the generation of an explicit rate. Third particular field values in the ABR table control the selection of an individual one of a plurality of rate decision blocks each indicating an individual rate of cell transmission from the station A to the station B. Each of the rate decision blocks includes a plurality of fields which control changes from the individual one of the rate decision blocks to a rate decision block generally providing a reduced rate of cell transmission. These changes are dependent in part upon the relative times for the reception and transmission by the station of the different types of cells. One step in controlling the cell transmission rate is to select the lower one of the explicit rate and the rate indicated in the individual one of the rate decision blocks. By providing these controls, an optimal, but not excessive, rate is selected to transmit the different cells.
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