Granted Patent B2

US 7,460,485 · App. 10/654,901 · Granted Dec 2, 2008

Abstract

Claims (98)

1. A method for guaranteeing a quality of service (QoS) in delivering real-time data across a transmission medium, comprising:

specifying a traffic requirement for a traffic stream in accordance with a generic first specification;

transforming the specified traffic requirement in accordance with a generic second specification based on the specified traffic requirement, an overhead requirement for the traffic stream and a condition of the transmission medium;

adjusting the generic second specification based on feedback obtained from monitoring the condition of the transmission medium;

aggregating a plurality of specifications for a plurality of traffic streams into a single specification to reduce resources required to maintain and process the plurality of specifications and overhead incurred in medium dedication;

generating a medium dedication schedule according to the single specification; and

performing medium dedication in accordance with the medium dedication schedule to coordinate transmission of the plurality of traffic streams.

2. The method according to claim 1 , further comprising:

monitoring, after performing medium dedication, the transmission medium to further tune the single specification to improve medium dedication scheduling and achieve a guaranteed quality of service for the plurality of traffic streams based on feedback obtained from monitoring the transmission medium.

3. The method according to claim 2 , further comprising:

monitoring the condition of the transmission medium; and

reporting the condition of the transmission medium to a scheduling entity.

4. The method according to claim 1 ,

wherein the generic first specification specifies traffic requirements and characteristics of real-time streaming applications, and

wherein the generic first specification specifies:

a highest bound and a lowest bound of bandwidth requirement;

an average data size in units of transmission;

a lifetime of a data unit;

a permitted variation on the duration for the data unit to reach a destination; and

a transmission rate used to deliver the data unit.

5. The method according to claim 1 ,

wherein the generic first specification specifies traffic requirements and characteristics of real-time block transfer applications, and

wherein the generic first specification specifies:

a highest bound and a lowest bound of bandwidth requirement;

an average data size in units of transmission;

a lifetime of a data unit; and

a transmission rate used to deliver the data unit.

6. The method according to claim 1 ,

wherein the generic second specification specifies:

a highest bound and a lowest bound of medium occupancy duration;

a highest bound and a lowest bound of dedication interval; and

a computation interval.

7. The method according to claim 1 , further comprising:

generating a medium dedication frame according to a medium dedication time;

inserting the medium dedication frame into a first-in, first-out (FIFO) queue in a position to be transmitted prior to frames in other queues.

8. A method for guaranteeing a quality of service (QoS) in delivering real-time data across a transmission medium, comprising:

specifying a traffic requirement for a traffic stream in accordance with a generic first specification;

transforming the specified traffic requirement in accordance with a generic second specification based on the specified traffic requirement, an overhead requirement for the traffic stream and a condition of the transmission medium;

adjusting the generic second specification based on feedback obtained from monitoring the condition of the transmission medium;

aggregating a plurality of specifications for a plurality of traffic streams into a single specification to reduce resources required to maintain and process the plurality of specifications and overhead incurred in medium dedication;

generating a medium dedication schedule according to the single specification;

performing medium dedication in accordance with the medium dedication schedule to coordinate transmission of the plurality of traffic streams;

determining, in units of transmission, a number of units for an amount of traffic to be transmitted within a duration interval, as one of a single data packet transmission and a burst transmission of a series of data packets;

determining the duration required to transmit a unit of transmission; and

multiplying the determined number of units with the determined duration,

wherein the generic second specification specifies:

a highest bound and a lowest bound of medium occupancy duration;

a highest bound and a lowest bound of dedication interval; and

a computation interval.

9. The method according to claim 8 , further comprising:

computing a medium occupancy duration required within a duration interval;

determining a number of medium dedications required within the duration interval in accordance with a medium dedication duration limit for an instance of medium dedication; and

dividing the duration interval by the determined number of medium dedications.

10. The method according to claim 9 , further comprising:

computing a dedication interval for the generic second specification;

computing a scaling factor from a delay bound to the dedication interval;

scaling a jitter bound by the scaling factor;

dividing the scaled jitter bound in half; and

adding the dedication interval to the divided scaled jitter bound.

11. The method according to claim 9 , further comprising:

computing a dedication interval for the generic second specification;

computing a scaling factor from a delay bound to the dedication interval;

scaling a jitter bound by the scaling factor, when the jitter bound is specified;

dividing the scaled jitter bound in half, when the jitter bound is specified; and

subtracting the divided jitter bound from the dedication interval, when the jitter bound is specified; and

setting the lowest bound of the dedication interval to zero, when the jitter bound is not specified.

12. The method according to claim 8 , further comprising:

scaling each of the plurality of specifications for the plurality of traffic streams to a common specification duration interval;

summing corresponding medium occupancy duration parameters of each of the scaled plurality of specifications;

selecting a lowest dedication interval parameter from among the scaled plurality of specifications; and

specifying the single specification based on the summed corresponding medium occupancy duration parameters and the selected lowest dedication interval parameter.

13. The method according to claim 8 , further comprising:

generating an individual medium dedication schedule for each of the plurality of traffic streams by:

determining a schedule period;

determining a medium dedication start time;

determining a medium dedication duration required for each instance of medium dedication;

computing a total medium dedication duration required during the schedule period;

computing N, a total number of medium dedication instances required during the schedule period, as N=Rounddown Int{T mdd /M dd }, T mdd being the total medium dedication duration required during the schedule period and M dd being the medium dedication duration required for each instance of medium dedication;

computing the medium dedication interval, M DI , as M DI =N p /N, N p being the schedule period; and

creating N data structures to store N individual medium dedication schedules.

14. The method according to claim 13 ,

wherein each of the N data structures comprise:

identification of a destination device for a scheduled medium dedication, a time value at which the medium dedication is scheduled to begin, and a duration value allocated for the medium dedication.

15. The method according to claim 13 , further comprising:

determining a smallest medium dedication interval from among the N individual medium dedication schedules;

determining a maximum number of medium dedications required from among the N individual dedication schedules, the maximum number of medium dedications being equal to the smallest non-prime integer value that is greater than the schedule period divided by the smallest medium dedication interval;

regenerating the individual medium dedication schedules for which a number of medium dedications required during the schedule period is not a factor of the determined maximum number of medium dedications; and

merging the individual medium dedication schedules into a unified medium dedication schedule.

16. The method according to claim 15 , wherein merging further comprises:

determining a medium dedication start time for each of the individual medium dedication schedules, wherein the medium dedication start time and a medium dedication end time equal to the sum of the medium dedication start time and medium dedication duration, are not within a range of a medium dedication time and a medium dedication duration of a medium dedication schedule structure for a work-in-process unified medium dedication schedule;

updating the individual medium dedication schedules with the medium dedication start time;

determining a new value for the total number of required medium dedications and the determined medium dedication duration;

determining a maximum number of required medium dedications, the maximum number of required medium dedications being equal to the smallest non-prime integer value that is greater than the schedule period divided by the smallest medium dedication interval; and

merging the individual medium dedication schedule with the work-in-process unified medium dedication schedule.

17. The method according to claim 16 ,

wherein the medium dedication schedule structure comprises identification of a destination device for a medium dedication scheduled by the individual medium dedication schedule, a time value at which the medium dedication is scheduled to begin, and a duration value allocated to the medium dedication.

18. The method according to claim 16 ,

wherein the determined new value of medium dedication duration corresponds to the smallest medium dedication interval among all medium dedication schedules greater than a previous value of medium dedication interval.

Assignments (10)