Patent ID: 6044060
Filing Date: 2000-03-28
Classification: H04L,H04Q

Abstract:
An ATM switch, comprising:traffic shaping means for regulating outgoing transmission of ATM cells from said ATM switch, said traffic shaping means comprisingmeans for determining an onward transmission time for each ATM cell received at said traffic shaping means, said onward transmission time being dependent for each ATM cell upon a time interval between a first time of arrival of a particular ATM cell on a virtual connection (VC) and a second time of arrival of the ATM cell which preceded said particular ATM cell on said VC,buffer means for storing each said ATM cell received at an address corresponding to said onward transmission time determined for that ATM cell, andmeans for outputting from said buffer means each of said ATM cells at times corresponding to the addresses of said buffer means whereinsaid means for determining an onward transmission time comprises a leaky bucket processor havingtimer means for timing the arrival of each ATM cell presented to the said traffic shaping means,memory means for storing a predetermined regular bucket increment, a current bucket level value, a bucket maximum value, and an onward transmission time for the previous cell on a given VC,calculating means for calculating the time difference between the arrival time of the cell and the stored onward transmission time for the preceding cell on the same VC, and for calculating a new bucket level from the time difference, the current bucket level, and the bucket level increment,subtraction means for subtracting the maximum level from the new level to give an overflow value and, if the overflow value is negative, for setting the value of the overflow to zero, andadding means for adding the overflow value to the current time to give the onward transmission time for the cell and for storing said time in the memory means.