Pmc-sierra, Inc.

Salman Ghufran

David Walden Wong

Vernon Robert Little

A variable bit rate scheduler for ATM traffic shaping which includes a service rate queue (SRQ) counter for generating a base traffic profile for the control of data transmission on a virtual channel, a virtual channel peak cell rate determinator coupled to said SRQ counter and operative to determine a virtual channel peak cell sub-rate, VC.sub.-- PCR, a leaky bucket having an input for receiving sub-tokens and an output for discharging tokens and means for adding sub-tokens at the virtual channel peak cell rate to the leaky bucket and, when a cell is to be transmitted, removing a number of tokens from the bucket equal to the ratio of a virtual channel sustainable cell rate. The virtual channel sustainable cell rate is a fraction of or equal to the virtual channel peak cell rate.

Variable bit rate scheduler

An ATM network interface comprising a physical layer interface having transmit and receive line interfaces, transmit and receive framers and overhead processors coupled to respective ones of the transmit and receive line interfaces and transmit and receive cell processors coupled to respective ones of transmit and receive framers and overhead processors. The interface further includes a segmentation and reassembly interface coupled to the physical layer interface having transmit and receive ATM and adaptation layer processors coupled to respective ones of the transmit and receive ATM cell processors and a transmit ATM Traffic Shaper coupled to said Transmit ATM and Adaptation Layer Processor, and a coupler to couple the segmentation and reassembly interface to a PCI bus. By incorporating the SAR unit on the same monolithic device as the remainder of the interface, one is able to eliminate the need for expensive external static RAM or SRAM for connection context memory.

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Burnaby, Canada

Salman Ghufran