A scheduler system for scheduling the distribution of ATM cells

摘要

A scheduling system for distributing asynchronous transfer mode (ATM) telephone signals from an ATM cell queuing device. The scheduling system includes a number of port shapers. A port shaper can support a number of flows with each flow identifying a number of ATM cells. A port shaper directs the flows to a single telephone service subscriber. Each flow assigned to a port shaper identifies ATM cells which are to be distributed to a different device used by a subscriber, such as a telephone or computer. A port shaper further includes a number of time descriptors. Flows are linked to the time descriptors. The time descriptors are sequentially activated. When a time descriptor becomes active, a flow linked to the time descriptor can emit an ATM cell, and after emitting the cell the flow is relinked to subsequent time descriptors based on a weighting increment I to accommodate different device bandwidths. Multiple flows may be linked to the same time descriptor. Since only one flow can emit an ATM cell at a time, arbitration is performed using a weighted round robin (WRR) engine to determine which flow emits a cell. The WRR engine functions using quality of service (QOS) parameters and weighting to determine which flow linked to the time descriptor gets to emit an ATM cell. <IMAGE>