System and Method for Allocating Bandwidth in Remote Equipment on a Passive Optical Network

Abstract

The present disclosure provides a system and method for allocating bandwidth in remote equipment on a passive optical network (PON), wherein the system includes an optical line terminal (OLT), which monitors the acceptance of traffic requesting the PON remote equipment for service and configures through signaling control the parameters for the operation of classifying, shaping, and scheduling the traffic in the remote equipment, and a remote equipment which classifies, shapes, and schedules the accepted traffic based on the parameters configured by the OLT and allocates a proper bandwidth to the accepted traffic, and outputs the traffic in the scheduled order. The present disclosure helps ensure the bandwidth and delay requirements of individual traffic flows in the PON remote equipment are met and interaction between traffic of the same or different service class groups is eliminated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing illustrating one embodiment of a PON architecture.

FIG. 2 is a schematic drawing illustrating the architecture of an embodiment of the system of the present disclosure.

FIG. 3 is a flow chart depicting an embodiment of the method of the present disclosure.

FIG. 4 is a schematic drawing illustrating the scheduling and buffer queuing within the scheduler of the present disclosure.

Claims

1. A system for allocating bandwidth to a plurality of remote equipment on a passive optical network (PON) and comprising: an optical line terminal (OLT) that controls the acceptance of traffic requesting service by the PON remote equipment and, through signaling control, classifies, shapes, and schedules the traffic in the remote equipment; andwherein the remote equipment classifies, shapes, and schedules the received traffic based on the parameters configured by the OLT, allocates a bandwidth to the received traffic, and outputs the traffic in the scheduled order.

2. The system of claim 1 wherein the remote equipment comprises: a classifier for classifying the traffic and placing the traffic of each service class into a corresponding buffer queue;a token bucket for shaping the traffic buffered in the classifier based on the token bucket restriction parameters configured by the OLT; anda scheduler that schedules the shaped traffic queues in each service class based on the scheduling parameters configured by the OLT and the preset scheduling algorithm, and outputs the traffic in the scheduled order.

3. The system of claim 2 wherein the service classes comprise guaranteed service, controlled-load service, and best effort service.

4. The system of claim 3 wherein the scheduler comprises: an intra-class scheduler that schedules the traffic queues in the shaped guaranteed service group and the controlled-load service group through a weighted fair queuing (WFQ) algorithm, and places the traffic in the scheduled guaranteed service group into a first transmit priority queue, traffic in the scheduled controlled-load service group into a second transmit priority queue, and traffic in the scheduled best effort service group into a third transmit priority queue; andan inter-class scheduler that adopts the absolute priority-based scheduling for all transmit priority queues once the transmit timeslot of the remote equipment arrives, wherein the traffic in the first transmit priority queue is sent first until all the traffic in this queue is sent, then the traffic in the second transmit priority queue is sent until all the traffic in this queue is sent, and finally the traffic in the third transmit priority queue is sent.

5. The system of claim 1 wherein the remote equipment comprises an optical network terminal (ONT) or an optical network unit (ONU).

6. The system of claim 1 wherein controling the acceptance of traffic requesting service by the PON remote equipment and classifying, shaping, and scheduling the traffic are accomplished through an OLT access permission control module built into the OLT.

7. A method for allocating bandwidth in passive optical network (PON) remote equipment, comprising: configuring, within the PON remote equipment, the parameters for classifying, shaping and scheduling operations; andthe PON remote equipment classifying, shaping, and scheduling the received traffic based on the configured parameters, allocating a corresponding bandwidth to the received traffic, and outputting the traffic in the scheduled order.

8. The method of claim 7 wherein the configuring comprises: the optical line terminal (OLT) configuring, through signaling control, the classification rules of the classifier, token bucket restriction parameters, and weight parameters for weighted fair queuing (WFQ) of the PON remote equipment.

9. The method of claim 8 wherein the configuring comprises: the OLT checking the bandwidth use state of the remote equipment and, when a traffic requests the remote equipment for service, the remote equipment reporting the bandwidth needed by the traffic to the OLT through signaling; andthe OLT determining whether the bandwidth available in the remote equipment can meet the bandwidth need of the traffic, and if so, determining that the remote equipment accepts the traffic; otherwise, determining that the remote equipment rejects the traffic, or the OLT proposing a parameter negotiation with the user requesting service of the traffic and determining that the remote equipment accepts the traffic if the bandwidth available in the remote equipment can meet the bandwidth need of the traffic after the negotiation.

10. The method of claim 7 wherein the classifying, shaping, and scheduling comprises: the remote equipment classifying the received traffic into a guaranteed service group, a controlled-load service group, and a best effort service group based on the classification rules configured by the optical line terminal (OLT), and placing each traffic of the guaranteed service class and the controlled-load service class into a separate buffer queue, while placing all traffic of best effort service class into a default buffer queue;the remote equipment adopting token buckets with different parameters for shaping each flow of the traffic in the guaranteed service group and the controlled-load service group based on the token bucket restriction parameters configured by the OLT; andthe remote equipment scheduling shaped traffic in the same service group using a weighted fair queuing (WFQ) algorithm and placing the traffic into corresponding transmit buffer queues, the remote equipment scheduling the shaped traffic in different service groups using the absolute priority-based scheduling and outputting the traffic.

11. The method of claim 10 wherein the adopting comprises: the token bucket having a mean rate equal to that of the traffic to be shaped and a depth equal to the maximum packet length of the traffic to be shaped.

12. The method of claim 10 wherein the scheduling shaped traffic comprises: the remote equipment scheduling shaped traffic queues in the guaranteed service group and the controlled-load service group using WFQ with each traffic queue assigned a weight configured by the OLT according to the characteristics of the traffic, and mixing the traffic of the best effort service group in the first in first out (FIFO) scheduler;the remote equipment placing the scheduled traffic in the guaranteed service group into a first transmit priority buffer queue, placing the scheduled traffic in the controlled-load service group into a second transmit priority buffer queue, and placing the traffic of the best effort service group into a third transmit priority buffer queue; andthe remote equipment adopting the absolute priority-based scheduling for all transmit priority queues once the transmit timeslot of the remote equipment arrives, wherein the traffic in the first transmit priority queue is sent first until all the traffic in this queue is sent, then the traffic in the second transmit priority queue is sent until all the traffic in this queue is sent, and finally the traffic in the third transmit priority queue is sent.

13. The method of claim 12 wherein the scheduling shaped traffic queues comprises: the remote equipment calculating the service start virtual time and service end virtual time for all shaped traffic queues in the guaranteed service group or control-load service group based on the weight configured for each traffic queue by the OLT, and scheduling and outputting the queue with the smallest service end virtual time and updating the system virtual time; andthe remote equipment recalculating the service start virtual time and service end virtual time for all traffic queues in the guaranteed service group or controlled-load service group, and scheduling and outputting the queue with the smallest recalculated service end virtual time; the remote equipment repeating the recalculating and rescheduling process until all queues are emptied.

14. The method of claim 8 wherein the classifying, shaping, and scheduling comprises: the remote equipment classifying the received traffic into a guaranteed service group, controlled-load service group, and a best effort service group based on the classification rules configured by the OLT, and placing each traffic of the guaranteed service class and the controlled-load service class into a separate buffer queue while placing all traffic of best effort service class into a default buffer queue;the remote equipment adopting a different token bucket with different parameters for shaping each flow of the traffic in the guaranteed service group, and controlled-load service group based on the token bucket restriction parameters configured by the OLT; andthe remote equipment scheduling shaped traffic in the same service group using the WFQ algorithm and placing the traffic into corresponding transmit buffer queues, the remote equipment scheduling the shaped traffic in different service group using the absolute priority-based scheduling and outputting the traffic.

15. The method of claim 14 wherein the adopting comprises: the token bucket having a mean rate equal to that of the traffic to be shaped and a depth equal to the maximum packet length of the traffic to be shaped.

16. The method of claim 14 wherein the scheduling shaped traffic comprises: the remote equipment scheduling shaped traffic queues in the guaranteed service group and controlled-load service group using the WFQ with each traffic queue assigned a weight configured by the OLT according to the type of the traffic, and mixing the traffic of the best effort service group in the first in first out (FIFO) scheduler;the remote equipment placing the scheduled traffic in the guaranteed service group into a first transmit priority buffer queue, placing the scheduled traffic in the controlled-load service group into a second transmit priority buffer queue, and placing the traffic of the best effort service group into a third transmit priority buffer queue; andthe remote equipment adopting the absolute priority-based scheduling for all transmit priority queues once the transmit timeslot of the remote equipment arrives, wherein the traffic in the first transmit priority queue is sent first until all the traffic in this queue is sent, then the traffic in the second transmit priority queue is sent until all the traffic in this queue is sent, and finally the traffic in the third transmit priority queue is sent.

17. The method of claim 16 wherein the adopting comprises: the remote equipment calculating the service start virtual time and service end virtual time for all shaped traffic queues in the guaranteed service group or control-load service group based on the weight configured for each traffic queue by the OLT and scheduling and outputting the queue with the smallest service end virtual time and updating the system virtual time; andthe remote equipment recalculating the service start virtual time and service end virtual time for all traffic queues in the guaranteed service group or controlled-load service group, and scheduling and outputting the queue with the smallest recalculated service end virtual time; the remote equipment repeating the recalculating and rescheduling process until all queues are emptied.

18. The method of claim 7 wherein the remote equipment comprises: an ONT or an ONU.