摘要 |
A method and a system for controlling a plurality of queues of an input port in a switching or routing system. The method supports the regular request-grant protocol along with speculative transmission requests in an integrated fashion. Each regular scheduling request or speculative transmission request is stored in request order using references to minimize memory usage and operation count. Data packet arrival and speculation event triggers can be processed concurrently to reduce operation count and latency. The method supports data packet priorities using a unified linked list for request storage. A descriptor cache is used to hide linked list processing latency and allow central scheduler response processing with reduced latency. The method further comprises processing a grant of a scheduling request, an acknowledgement of a speculation request or a negative acknowledgement of a speculation request. Grants and speculation responses can be processed concurrently to reduce operation count and latency. A queue controller allows request queues to be dequeued concurrently on central scheduler response arrival. Speculation requests are stored in a speculation request queue to maintain request queue consistency and allow scheduler response error recovery for the central scheduler.
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