MANIPULATING DATA STREAMS IN DATA STREAM PROCESSORS

摘要

Techniques for performing user-configurable traffic management functions on streams of packets. The functions include multicasting, discard, scheduling, including shaping, and segmentation and reassembly. In the techniques, the functions are not performed directly on the packets of the stream, but instead on descriptors that represent stored packets. A packet's descriptor includes at least an identifier for the packet and a specifier for a set of traffic management functions to be performed on the descriptor. The user configures a set of traffic management functions for a traffic queue of descriptors. In multicasting, a descriptor is copied and placed on more than one traffic queue; with regard to discard, the descriptor is placed in a discard traffic queue. Packets represented by descriptors in a discard traffic queue are discarded from the buffer. Output of descriptors from all traffic queues, including discard traffic queues, is scheduled. Scheduling is done using a hierarchy of schedulers. The techniques are implemented in a traffic management coprocessor integrated circuit. Also disclosed are a modified partial packet discard algorithm and a frame based deficit round robin scheduling algorithm.