An apparatus for link layer port-based hardware implemented acceptance
rate limiting control is presented. The apparatus employs a single
up-down counter tracking a receive port buffer occupancy level. The
single up-down counter is incremented by a receive line rate clock signal
time truncated by a frame receive signal and a feedback frame acceptance
control signal. The single up-down counter is decremented at an Service
Level Agreement (SLA) agreed upon committed rate at which content is
extracted from the receive port buffer. Outputs of comparators
determining when the port receive buffer occupancy level is below a low
watermark receive port buffer occupancy level, and when the receive port
buffer occupancy level is above a maximum burst size, are provided to a
master slave flip flop generating the frame acceptance control signal
exhibiting hysteresis as the port receive buffer occupancy level
transitions between the low watermark and the maximum burst size receive
port buffer occupancy levels. The advantages of the link layer port-based
hardware implemented acceptance rate limiting control achieved are
derived from a deterministic response enforced in real time, at line
rate, as content is being received employing a small number of logic
gates.