Apparatus and methods for access fairness for a multiple target bridge/router in a fibre channel arbitrated loop system

A method operable in a bridge device adapted to couple a plurality of devices to a Fibre Channel Arbitrated Loop (FC-AL) communication medium, the method comprising:

• providing arbitration information in a Fibre Channel layer 2 logic circuit of the bridge device for each of multiple Target Arbitrated Loop Physical Addresses (T-ALPAs) managed by the bridge device, the arbitration information including a request indicator for each of the multiple T-ALPAs and an access window indicator for each of the multiple T-ALPAs;
• generating arbitration signals in the Fibre Channel layer 2 logic circuit derived from the arbitration information;
• applying the arbitration signals to an FC-AL layer logic circuit of the bridge device, the FC-AL layer logic circuit including a Loop Port State Machine;
• utilizing the arbitration signals within the FC-AL layer logic circuit to control arbitration exchanges in the FC-AL communication medium to control arbitration exchanges on the FC-AL communication medium to provide access fairness for all T-ALPAs managed by the bridge device based on the arbitration signals in cooperation with access fairness provided by any other devices coupled to the FC-AL communication medium.

A system comprising:

• a Fibre Channel Arbitrated Loop (FC-AL) communication medium;
• a Fibre Channel (FC) device coupled to the FC-AL communication medium wherein the FC device implements access fairness features of the FC-AL standards;
• a bridge device coupled to the FC-AL communication medium;
• and
• a plurality of devices coupled to the bridge device wherein the bridge device associated one of multiple Target Arbitrated Loop Physical Addresses (T-ALPAs) with each of the plurality of devices,
• wherein the bridge device further comprises:
• a Fibre Channel layer 2 logic circuit adapted to implement FC2 features of the Fibre Channel protocol and adapted to maintain arbitration information for each of multiple T-ALPAs, the arbitration information comprising a request indicator for each of the multiple T-ALPAs and an access window indicator for each of the multiple T-ALPAs, the Fibre Channel layer 2 logic circuit further adapted to generate arbitration signals derived from the arbitration information;
• and
• an FC-AL layer logic circuit including a Loop Port State Machine logic circuit, the Loop Port State Machine coupled to receive arbitration signals from the Fibre Channel layer 2 logic circuit and adapted to control arbitration exchanges on the FC-AL communication medium and adapted to provide access fairness for all T-ALPAs based on the arbitration signals in cooperation with access fairness provided by any other devices coupled to the FC-AL communication medium.