Patent ID: 6064677
Filing Date: 2000-05-16
Classification: H04L,H04Q

Abstract:
In a packet switched communication system, an apparatus for granting packets of multiple constant bit rate flows time multiplexed, serial access during successive time slots to a shared resource of said system in substantial compliance with individual network traffic contracts for the respective flows, said apparatus comprising:a queuing mechanism organizing pending packets of active flows in respective queues, with said queues having an oldest pending packet at head of queue order;a scheduling mechanism coupled to said queuing mechanism, said scheduling mechanism scheduling the oldest pending packets of the respective flows for service at times which are selected in accordance with the respective network traffic contracts for such flows, said scheduling mechanism including a relatively high priority calendar queue and a relatively low priority calendar cueue and said scheduling mechanism preferentially resolving any scheduling conflicts between packets of flows having relatively high and relatively low contractually specified packet emission rates, respectively, in favor of servicing packets of said high emission rate flows first, thereby enforcing a serialized service schedule on the packets of said active flows, while preferentially distributing delay caused by such conflict resolution to the lower emission rate flows; anda transmit mechanism coupled to said queuing mechanism and to said scheduling mechanism, said transmit mechanism transferring packets of said active flows to said shared resource in accordance with said serialized service schedule, said packets being logically transformed for subsequent operation of said traffic shaper from a pending state to a serviced state upon being transferred to said shared resource.