Apparatus and method for programmably modifying a limit of a retry counter in a network switch port in response to exerting backpressure

A method for controlling a port of a network switch in a computer network comprising the steps of:

• incrementing a retry count in a retry counter within the port each time the port attempts and fails to transfer a data packet over the computer network, the retry count having a retry limit value;
• sensing whether backpressure is exerted by the port over the computer network;
• resetting the retry count in the retry counter to a start value when backpressure is exerted by the port onto the computer network;
• selectively modifying the retry limit value of the retry count each time the retry count is reset according to predetermined programmed information such that a total number of transfer attempts for an individual data packet does not exceed a maximal retry limit value determined based on the predetermined programmed the information;
• and
• discarding an individual data packet when the retry count has reached the retry limit value.

A media access control (MAC) arrangement comprising:

• a retry counter that maintains a retry count of the number of failed attempts at transmission of data by a MAC onto a computer network, the retry count having a retry limit value;
• control logic that monitors the assertion of backpressure onto the computer network by the MAC;
• a retry counter reset signal generator responsive to assertion of the backpressure to generate a retry counter reset signal that resets the retry count to a start value;
• and
• programmable retry limit modification logic within the control logic that is configured to receive predetermined programmed information from an external switch engine and selectively modifies the retry limit value of the retry count based upon the predetermined programmed information in response to the assertion of backpressure by the MAC.