International Business Machines Corporation

University of Massachusetts

Victor Firoiu

Gary Scott Delp

Roch A Guerin

Philip Lynn Leichty

Rajendran Rajan

John Handley Shaffer

Donald F Towsley

Vinod Gerard Peris

David Richard Poulter

James F Kurose

A method and apparatus are provided for scheduling the transmission of cells of a plurality of data streams in a communications network. An earliest deadline first (EDF) scheduler is provided for scheduling the transmission of cells of a plurality of data streams in a communications network to ensure that the connection or data stream with the earliest deadline is transmitted first. Each of the multiple data streams has a delay bound or deadline. Data of each data stream is enqueued to a corresponding data cell queue. A timing wheel time slot based on an identified target transmission time for each data cell queue is calculated utilizing an addition of a maximum delay value. A move forward timing mechanism includes a scan forward feature to identify a succession of virtual connection or data stream cell queues for transmission. A multiple tier cell scheduler is provided that includes at least two scheduling timing wheels. The priority of a first timing wheel is higher than the priority of a second timing wheel. The priority of the second timing wheel is higher than the priority of an optional third timing wheel. The third timing wheel includes a best effort operational mode. The relative rates between data streams are maintained, while the absolute rates of the data streams are increased or decreased in the lowest priority wheel.

Earliest deadline first communications cell scheduler and scheduling

A network component performs flow admission control. A function F(t) is provided which characterizes resources available at the network component. Information characterizing a proposed flow is received and used to define an envelope A(t). It is then attempted to fit the envelope within F(t) and the flow is accepted or rejected based on the attempt to fit the envelope.

Flow admission control for a router

Growing community of inventors

Amherst, MA, United States of America

Victor Firoiu