Dynamically adjusted credit based round robin scheduler

摘要

A credit based queue scheduler dynamically adjusts credits depending upon at least a moving average of incoming packet size to alleviate the impact of traffic burstiness and packet size variation, and increase the performance of the scheduler by lowering latency and jitter. For the case when no service differentiation is required, the credit is adjusted by computing a weighted moving average of incoming packets for the entire scheduler. For the case when differentiation is required, the credit for each queue is determined by a product of a sum of credits given to all queues and priority levels of each queue.

主权项

1. A routing method, comprising steps of:
receiving incoming Internet Protocol (IP) packets at a router; placing a first plurality of the received IP packets intended for an output port of the router in a first queue of a round robin scheduler of the router; placing a second plurality of the received IP packets intended for the output port of the router in a second queue of the round robin scheduler of the router; computing a moving average over time for incoming packet size, from sizes of the IP packets received at the router, the moving average being computed from an average of both the first plurality of IP packets and the second plurality of IP packets over a predetermined period of time; weighting the moving average based on a previous moving average from a previous period of time; dynamically determining a first credit of the round robin scheduler for the first queue and a second credit of the round robin scheduler for the second queue based on the weighted moving average; determining priorities of the first queue and the second queue; comparing the priorities of the first queue and the second queue to each other; wherein:
the first credit and the second credit are set as the weighted moving average when the comparison indicates that the priorities of the first queue and the second queue are the same, andthe first credit and the second credit are computed by multiplying the weighted moving average of the IP packets received at the router by a first percentage weight and a second percentage weight respectively when the comparison indicates that the priorities of the first queue and the second queue are different, the first percentage weight being different than the second percentage weight; and operating the round robin scheduler to take IP packets form the first and second queues in a round robin fashion, for transmission from the router via the output port, in respective amounts based on the dynamically determined first credit and second credit.