Allocated and dynamic switch flow control

A network switch for controlling flow of at least one data unit within a telecommunications network, comprising:

• at least one input port for receiving the at least one data unit into the switch;
• at least one output port for transmitting the at least one data unit out of said switch;
• at least one input buffer queue associated with said at least one input port for enqueuing the at least one data unit received at the at least one input port;
• at least one output buffer queue associated with said at least one input buffer queue for receiving and temporarily storing the at least one data unit from said at least one input buffer queue;
• at least one transmission request generator operative to generate one or more requests for permission to transmit the at least one data unit from said at least one input buffer queue to said at least one output buffer queue;
• at least one feedback message generator operative to provide at least one feedback message to said at least one input buffer queue, said at least one feedback message including a signal having first and second states, said first and second states respectively indicating no operation and an instruction to cease sending requests for permission to transmit, and wherein each of said at least one input buffer queue receiving the signal in the second state from one or more of said at least one output buffer queue ceases submitting requests to transmit to said one or more of said at least one output buffer queue.

A method for controlling flow of at least one inputted cell within a network switch having a plurality of input buffers associated with at least one input queue and a plurality of output buffers associated with at least one output queue, the method comprising the steps of:

• receiving the at least one inputted cell in the switch, the cell being received in the input queue of the input memory;
• forwarding a request to transmit the at least one inputted cell to one of said at least one output queue;
• and
• asserting, when a traffic type cell count of all cells shared by all existing connections is not greater than or equal to a first limit and a dynamic buffer count associated with one of said at least one output queue is greater than or equal to a second limit, both a first signal denying said request and a second signal causing cessation of forwarding requests to transmit to the one output queue.

A system for controlling flow of a received data unit in a network switch, comprising:

• an input queue associated with a receive buffer for storing the received data unit, the input queue associated with an input port, a first traffic type, and a first connection;
• a plurality of traffic type output queues associated with an output port, each one of the plurality of traffic type output queues further associated with a respective traffic type, each one of the traffic type output queues including a plurality of connection specific output queues;
• and
• a feedback message generator operative to determine whether there is insufficient buffer space in one of the connection specific output queues associated with the first connection included in one of the traffic type output queues associated with the first traffic type and the first output port, the feedback message generator further operative to provide a first feedback message to the input queue responsive to determining there is insufficient buffer space in the one of the connection specific output queues associated with the first connection included in the one of the traffic type output queues associated with the first traffic type and the first output port.

A method for controlling flow of a data unit within a network switch, comprising:

• receiving the data unit in the switch, the data unit being received at an input port associated with an input queue, the input queue associated with at least one input buffer;
• storing the data unit in the at least one input buffer associated with the input queue;
• at least at some times, forwarding a plurality of requests to transmit the data unit from the input port to a plurality of output queues, the plurality of output queues associated with a respective plurality of output ports;
• providing, by at least one of the respective plurality of output ports in response to the plurality of requests to transmit, a feedback message to the input port denying the request to transmit the data unit in the event that a total number of the output buffers associated with the respective output queue and available for data unit storage is less than are needed to store the data unit;
• and
• delaying transmission of the data unit from the input queue to the respective plurality of output ports in the event that the at least one of the output ports provides the feedback message denying the request to transmit the data unit.