Method for limiting the transmission of data generated by a data source
First Claim
1. A method of limiting the transmission rate of data generated from a data source, packaged in fixed sized cells, to a data rate RATE and to a burst rate BURST, the values of both RATE and BURST rates expressed as a multiple of the time to transmit one of said cells, said method comprising the steps of:
- setting a variable CREDIT equal to its previous value plus the difference between a current clock time TNOW and a previous clock time TLAST, said difference expressed in units of the time to transmit one of said cells;
setting said variable CREDIT to the minimum of said variable CREDIT and said burst rate BURST;
comparing said variable CREDIT to said data rate RATE;
if said variable CREDIT is greater than or equal to said data rate RATE;
transmitting one data cell;
subtracting said data rate RATE from said variable CREDIT;
setting said previous clock time TLAST equal to the current clock time TNOW ;
determining whether there is more data to be transmitted;
if there is more data to be transmitted, repeating said step of comparing; and
wherein said variables CREDIT, RATE and BURST are integers.
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Abstract
A novel method of calculating and enforcing user traffic parameters on an ATM network is disclosed. The method of the present invention provides very accurate calculation results for the amount of bandwidth consumed by an application. The method can be utilized to limit both the average traffic rate and the maximum burst rate of an application. The disclosed method achieves high efficiency by requiring minimal intervention from a processor and by requiring only additions and subtractions with no multiplications or divisions for its core operations.
17 Citations
3 Claims
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1. A method of limiting the transmission rate of data generated from a data source, packaged in fixed sized cells, to a data rate RATE and to a burst rate BURST, the values of both RATE and BURST rates expressed as a multiple of the time to transmit one of said cells, said method comprising the steps of:
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setting a variable CREDIT equal to its previous value plus the difference between a current clock time TNOW and a previous clock time TLAST, said difference expressed in units of the time to transmit one of said cells; setting said variable CREDIT to the minimum of said variable CREDIT and said burst rate BURST; comparing said variable CREDIT to said data rate RATE; if said variable CREDIT is greater than or equal to said data rate RATE; transmitting one data cell; subtracting said data rate RATE from said variable CREDIT; setting said previous clock time TLAST equal to the current clock time TNOW ; determining whether there is more data to be transmitted; if there is more data to be transmitted, repeating said step of comparing; and wherein said variables CREDIT, RATE and BURST are integers. - View Dependent Claims (2, 3)
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Specification