Feedback priority modulation rate controller

A device for routing data transmission units (DTUs) from a source to a destination comprising:

• at least one input port for receiving incoming DTUs from the source;
• at least one output port for transmitting DTUs to the destination;
• a switch fabric for switching transmitting DTUs from one of the at least one input port to one of the at least one output port;
• a controller for controlling an input rate of the in put port and for controlling an output rate of the output port;
• measurement means for measuring the output rate of the output port, the measurement means transmitting the output rate to the controller, wherein the controller adjusts the input rate based on the output rate.

A method of allocating resource units between high priority tasks and low priority tasks, the method comprising:

• a) establishing a desired minimum number of resource units (x) to be allocated to a task;
• b) establishing a desired maximum number of resource units (y) to be allocated to a task;
• c) establishing a first upper limit to resource units to be requested for high priority tasks, the first upper limit being equal to the desired minimum number of resource units (x);
• and d) establishing a second upper limit to resource units to be requested for low priority tasks, the second upper limit being equal to the desired maximum number of resource units (y).