Granted Patent B2

US 8,792,499 · App. 12/985,108 · Granted Jul 29, 2014

Abstract

Claims (49)

1. A method of scheduling an optical network, the method comprising:

receiving at a scheduling server status information concerning at least one transmit queue for a plurality of optical pass-through switches (OptSws);

determining a schedule for one or more transmissions to take place in a cycle based on the status information for the plurality of OptSws, the determining including:

for a wavelength that is available to transmit a transmission,

removing one or more unsupportable transmissions from a candidate transmission list,

determining a first transmission of the candidate transmission list, the first transmission being the one of the transmissions of the candidate transmission list which most preferably satisfies a given parameter;

updating a usage list to reflect determination of the first transmission; and

replacing the candidate transmission list with the residue set of the first transmission; and

forwarding a control message to the plurality of OptSws in order that the schedule may be implemented at the plurality of OptSws.

2. The method of claim 1 wherein the status information includes an indication of at least one parameter from the group consisting of current buffer size of a transmit queue, head of queue packet delay for a transmit queue, and an estimated time of buffer overflow for a transmit queue.

3. The method of claim 2 wherein the indication details a relationship of the parameter to one or more thresholds.

4. The method of claim 1 wherein the status information includes an identification of an egress OptSw for a queued transmission.

5. The method of claim 1 wherein the control message is at least one of a transmission setup message, transmission termination message, and queue statistics collection message.

6. The method of claim 1 wherein the control message is a transmission setup message, the transmission setup message including wavelength specific information that informs establishment of a direct optical path from a first OptSw to an second OptSw.

7. The method of claim 1 wherein the control message includes an indication for at one of the plurality of OptSws to perform at least one of: disabling a transmitter, enabling a transmitter, disabling a receiver, enabling a receiver, disabling a blocking module, enabling a blocking module.

8. The method of claim 1 wherein forwarding the control message to the plurality of OptSws in order that the schedule may be implemented at the plurality of OptSws comprises:

forwarding the control message based on the usage list.

9. The method of claim 1 wherein the given parameter is largest residue set, largest k-residue set, shortest path, or shortest k-path, and the first transmission correspondingly has a largest residue set, a largest k-residue set, a shortest path, or a shortest k-path for the transmissions of the candidate transmission list.

10. The method of claim 1 wherein the first transmission is

a transmission having a longest path when two or more of the transmissions of the candidate transmission list have a same size residue set; and

when two or more of the transmissions of the candidate transmission list have a same size residue set and a same size path, a selected one of the two or more transmissions.

11. The method of claim 1 wherein determining the schedule for one or more transmissions to take place in a next cycle based on the status information for the plurality of OptSws further comprises:

determining an intermediate OptSw that may tap into the first transmission on the wavelength; and

determining an originating OptSw of the first transmission on the wavelength that may transmit to an intermediate OptSw and a terminating OptSw.

12. An apparatus for scheduling an optical network, the apparatus including a processor and a memory device, the processor configure to:

receive status information concerning at least one transmit queue for a plurality of optical pass-through switches (OptSws);

determine a schedule for one or more transmissions to take place in a cycle based on the status information for the plurality of OptSws, the determining including:

for a wavelength that is available to transmit a transmission,

removing one or more unsupportable transmissions from a candidate transmission list,

determining a first transmission of the candidate transmission list, the first transmission being the one of the transmissions of the candidate transmission list which most preferably satisfies a given parameter;

updating a usage list to reflect determination of the first transmission; and

replacing the candidate transmission list with the residue set of the first transmission; and

forward a control message to the plurality of OptSws in order that the schedule may be implemented.

13. The apparatus of claim 12 wherein the status information includes an indication of a parameter from the group consisting of current buffer size of a transmit queue, head of queue packet delay for a transmit queue, and an estimated time of buffer overflow for a transmit queue.

14. The apparatus of claim 13 wherein the indication details a relationship of the parameter to one or more thresholds.

15. The apparatus of claim 12 wherein the status information includes an identification of one or more egress OptSws for a queued transmission.

16. The apparatus of claim 12 wherein the control message is at least one of a transmission setup message, transmission termination message, and queue statistics collection message.

17. The apparatus of claim 12 wherein the control message is a transmission setup message, the transmission setup message including wavelength specific information that informs establishment of a direct optical path from a first OptSw to an second OptSw.

18. The apparatus of claim 12 wherein the control message includes an indication for at one of the plurality of OptSws to perform at least one of: disabling a transmitter, enabling a transmitter, disabling a receiver, enabling a receiver, disabling a blocking module, enabling a blocking module.

19. The apparatus of claim 12 wherein forwarding the control message to the plurality of OptSws in order that the schedule may be implemented at the plurality of OptSws comprises:

forwarding the control message based on the usage list.

20. The apparatus of claim 12 wherein the given parameter is largest residue set, largest k-residue set, shortest path, or shortest k-path, and the first transmission correspondingly has a largest residue set, a largest k-residue set, a shortest path, or a shortest k-path for the transmissions of the candidate transmission list.

21. The apparatus of claim 12 wherein the first transmission is

a transmission having a longest path when two or more of the transmissions of the candidate transmission list have a same size residue set; and

when two or more of the transmissions of the candidate transmission list have a same size residue set and a same size path, a selected one of the two or more transmissions.

22. The apparatus of claim 12 further comprising

a blocking module, for blocking a wavelength from passing through the apparatus;

add module for adding a wavelength to a signal exiting the apparatus;

drop module for directing a wavelength from a signal entering the apparatus to further processing.

Assignments (11)