Patent ID: 8274896

Claim:
An apparatus comprising: a real queue configured to actually receive data units; and a virtual queue configured to: virtually receive virtual data units as the data units are actually received by a real queue, virtually dispatch virtual data units at a drain rate that differs from and is a predefined multiple of a drain rate of the real queue, wherein the virtual queue is configured to maintain a committed token count and an excess token count; and wherein the committed token count is configured to represent a number of bytes available to be allocated to a committed burst having a maximum size; wherein the maximum token size of the committed burst is a threshold value; and wherein the virtual queue is configured to, in response to a data unit virtually exiting the virtual queue: if the excess token count is less than the maximum token size of an excess burst, increase the excess token count, otherwise, if the committed token count is less than the maximum token size of the committed burst, increase the committed token count, otherwise, increase neither the excess token count nor the committed token count.