Partially preemptive burst scheduling model for an optical burst switching network

A method of scheduling data bursts for transmission on one of a plurality of outgoing channels in a router in an optical burst switched (“OBS”) node, the method comprising the steps of:

• responsive to a determination that a data burst to be scheduled overlaps with an already-scheduled data burst on each of the plurality of outgoing channels, determining an optimum channel with respect to which the already-scheduled data burst thereon overlaps the least amount with the data burst to be scheduled;
• dropping a portion of the already-scheduled data burst on the optimum channel that overlaps with the data burst to be scheduled;
• if the overlapping portion of the already-scheduled data burst on the optimum channel exceeds a predetermined threshold value, dropping the entire already-scheduled data burst on the optimum channel;
• and
• scheduling the data burst to be scheduled on the optimum channel.

A method of scheduling data bursts for transmission on one of a plurality of outgoing channels in a router in an optical burst switched (“OBS”) node, the method comprising the steps of:

• responsive to a determination that a data burst to be scheduled overlaps with an already-scheduled data burst on each of the plurality of outgoing channels, determining an optimum channel with respect to which the already-scheduled data burst thereon overlaps the least amount with the data burst to be scheduled;
• dropping a portion of the already-scheduled data burst on the optimum channel that overlaps with the data burst to be scheduled;
• scheduling the data burst to be scheduled on the optimum channel;
• determining whether there is sufficient time to modify a Burst Header Packet (“BHP”) of the already-scheduled data burst on the optimum channel prior to transmission thereof;
• responsive to a determination that there is sufficient time to modify the BHP, modifying a length value there of;
• responsive to a determination that there is not sufficient time to modify the BHP, generating an error message.

A method of scheduling data bursts for transmission on one of a plurality of outgoing channels in a router in an optical burst switched (“OBS”) node, the method comprising the steps of:

• responsive to a determination that a data burst to be scheduled overlaps with an already-scheduled data burst on each of the plurality of outgoing channels, determining an optimum one of the outgoing channels with respect to which the already-scheduled data burst thereon overlaps the least amount with the data burst to be scheduled;
• responsive to a priority of the already-scheduled data burst on the optimum channel being higher than that of the data burst to be scheduled:
• dropping a portion of the data burst to be scheduled that overlaps with the already-scheduled data burst on the optimum channel;
• and
• scheduling a remaining portion of the data burst to be scheduled on the optimum channel;
• and
• responsive to a priority of the data burst to be scheduled being higher than that of the already-scheduled data burst on the optimum channel:
• preempting a portion of the already-scheduled data burst on the optimum channel that overlaps with the data burst to be scheduled;
• and
• scheduling the data burst to be scheduled in its entirety.

Apparatus for scheduling data bursts for transmission on one of a plurality of outgoing channels in a router in an optical burst switched (“OBS”) node, the apparatus comprising:

• means responsive to a determination that a data burst to be scheduled overlaps with an already-scheduled data burst on each of the plurality of outgoing channels for determining an optimum channel with respect to which the already-scheduled data burst thereon overlaps the least amount with the data burst to be scheduled;
• means for dropping a portion of the data burst to be scheduled that overlaps with the already-scheduled data burst on the optimum channel;
• and
• means for scheduling a remaining portion of the data burst to be scheduled on the optimum channel.

Apparatus for scheduling data bursts for transmission on one of a plurality of outgoing channels in a router in an optical burst switched (“OBS”) node, the apparatus comprising:

• means responsive to a determination that a data burst to be scheduled overlaps with an already-scheduled data burst on each of the plurality of outgoing channels for determining an optimum channel with respect to which the already-scheduled data burst thereon overlaps the least amount with the data burst to be scheduled;
• means for dropping a portion of the already-scheduled data burst on the optimum channel that overlaps with the data burst to be scheduled;
• means responsive to the overlapping portion of the already-scheduled data burst on the optimum channel exceeding a predetermined threshold value for dropping the entire already-scheduled data burst on the optimum channel;
• and
• means for scheduling the data burst to be scheduled on the optimum channel.

Apparatus for scheduling data bursts for transmission on one of a plurality of outgoing channels in a router in an optical burst switched (“OBS”) node, the apparatus comprising:

• means responsive to a determination that a data burst to be scheduled overlaps with an already-scheduled data burst on each of the plurality of outgoing channels for determining an optimum channel with respect to which the already-scheduled data burst thereon overlaps the least amount with the data burst to be scheduled;
• means for dropping a portion of the already-scheduled data burst on the optimum channel that overlaps with the data burst to be scheduled;
• means for scheduling the data burst to be scheduled on the optimum channel;
• means for determining whether there is sufficient time to modify a Burst Header Packet (“BHP”) of the already-scheduled data burst on the optimum channel prior to transmission thereof;
• means responsive to a determination that there is sufficient time to modify the BHP for modifying a length value thereof;
• means responsive to a determination that there is not sufficient time to modify the BHP for generating an error message.