Patent ID: 7085846

Claim:
A method for providing buffer-to-buffer credit port-level flow control for a computer network in operative communication with a plurality of ingress and egress network processors, each having an egress port and an ingress port that is associated with a buffer-to-buffer credit value corresponding to the current number of frames the ingress port sends, a buffer value corresponding to the current total frame size the ingress port sends, and a pending buffer-to-buffer value corresponding to the pending buffer-to-buffer credits an egress port issues the ingress port, and a set of network processors is associated with a bridge, the method comprising the steps of: sending a frame from the ingress port to a destination egress port, if the ingress port has a sufficient buffer-to-buffer credit value and buffer value; decrementing the buffer-to-buffer credit value associated with the ingress port; decrementing the buffer value associated with the ingress port; determining whether to increment the buffer-to-buffer credit value associated with the ingress port by incrementing the buffer-to-buffer credit value associated with the ingress port if the product of one plus the buffer-to-buffer credit value times the maximum frame size in bytes is less than or equal to a minimum egress buffering value; the minimum egress buffering value corresponds to the minimum amount of egress buffering that is available for any one egress port; incrementing the pending credit value associated with the ingress port; determining whether to send a credit message to the ingress port; the computer network further comprises a switch fabric: and wherein the network processors are in operative communication with the switch fabric via the associated bridge.