Method and apparatus for arbitration and fairness on a full-duplex bus using dual phases

1. A computer-readable medium containing instructions which, when executed by a computer, provide an arbitration fairness protocol in a full-duplex communications system having a plurality of nodes sending arbitration requests to a BOSS node, by performing the acts of:

providing a first arbitration phase, a second arbitration phase, and an arbitration advancing means;

sending an arbitration reset command for the first arbitration phase by the BOSS node;

granting arbitration by the BOSS node of arbitration requests made by the plurality of nodes for said first arbitration phase during said second arbitration phase;

granting arbitration by the BOSS node of arbitration requests made by the plurality of nodes for said first arbitration phase during said first arbitration phase;

advancing to said second arbitration phase according to said advancing means;

sending an arbitration reset command for said second arbitration phase by the BOSS node;

granting arbitration by the BOSS node of arbitration requests made by the plurality of nodes for said second arbitration phase during said first arbitration phase; and

granting arbitration by the BOSS node of arbitration requests made by the plurality of nodes for said second arbitration phase during said second arbitration phase.

2. The computer-readable medium of claim 1 , wherein said advancing means includes a timer.

3. The computer-readable medium of claim 1 , wherein said advancing means is accomplished by the BOSS node.

4. The computer-readable medium of claim 1 , wherein said first arbitration phase is an odd arbitration phase.

5. The computer-readable medium of claim 1 , wherein said second arbitration phase is an even arbitration phase.

6. The computer-readable medium of claim 1 , comprising the additional act of repeating said arbitration fairness protocol as often as the BOSS node deems necessary.

7. A computer-readable medium containing instructions which, when executed by a computer, provide access to arbitration in a full-duplex communications system having a plurality of nodes communicating in an asynchronous manner, each of the nodes having an arbitration indicator therein, by performing the acts of:

providing a current arbitration phase and an inactive arbitration phase;

determining whether one of said plurality of nodes wishes to arbitrate on the full-duplex communications system;

if one of said nodes wishes to arbitrate, determining further whether the arbitration indicator within said node is set;

sending an arbitration request on said full-duplex communications system for the active arbitration phase by said node if said arbitration indicator is set;

sending an arbitration request on said full-duplex communications system for the inactive arbitration phase by said node if said arbitration indicator is reset; and

sending an arbitration denial for said current arbitration phase if said node does not wish to arbitrate.

8. The computer-readable medium of claim 7 , wherein said current arbitration phase is an odd arbitration phase, and said inactive arbitration phase is an even arbitration phase.

9. The computer-readable medium of claim 7 , wherein said arbitration indicator is an arbitration enable flag as provided for in the P1394b standard.

10. A computer-readable medium containing instructions which, when executed by a computer, provide access to arbitration in a full-duplex communications system having a plurality of nodes communicating in an isochronous manner, by performing the acts of:

providing a current arbitration phase and an inactive arbitration phase;

determining whether one of said plurality of nodes wishes to arbitrate on the full-duplex communications system;

if one of said nodes wishes to arbitrate, sending an arbitration request on said full-duplex communications system for the active arbitration phase by said node if said arbitration indicator is set; and

sending an arbitration denial request on said full-duplex communications system for said current arbitration phase if said node does not wish to arbitrate.

11. The method of claim 10 , wherein said current arbitration phase is an odd arbitration phase, and said inactive arbitration phase is an even arbitration phase.

12. The method of claim 10 , wherein said arbitration indicator is an arbitration enable flag as provided for in the P1394b standard.