Technique for supporting tiers of traffic priority levels in a packet-switched network

Abstract

The technique of the present invention provides a simple and efficient solution to the problem of supporting differentiated priority levels within a QoS service class within a packet-switched network. When a bandwidth request is received at the cable modem head end, the service ID of that particular cable modem is identified. From this service ID, the associated static priority value of the requesting modem's service class is determined. The grant scheduler at the CMTS maintains a single queuing structure to temporarily store all differentiated priority bandwidth requests associated with a particular class of service that are received from cable modems on a selected channel. The technique of the present invention implements a procedure to calculate a metric used in determining a queuing priority for each received bandwidth request so that a single priority queuing structure may be used for this purpose. The metric is calculated by subtracting a product of the static priority value from the arrival time value of an associated bandwidth request. Use of the static service class priority in the queuing priority metric helps the grant scheduler to prioritize bandwidth requests from high priority modems over requests from low priority modems in the same queuing structure. Use of the arrival time in the metric enables an implicit fairness feature in the traffic prioritization to prevent starvation of low priority traffic.