Matching schemes with captured-frame eligibility for input-queued packet switches

Virtual output queues (VOQs) are widely used by input-queued (IQ) switches to eliminate the head-of-line (HOL) blocking phenomena, which limits switching performance. An effective matching scheme must provide high throughput under several admissible traffic patterns and keep implementation complexity low. A variety of matching schemes for IQ switches that deliver high throughput under uniform traffic have been proposed. However, there is a need of matching schemes that provide high throughput under several admissible traffic patterns, including those with nonuniform distributions. In this paper, we introduce the captured frame-size concept for matching schemes in IQ switches. We use the captured-frame eligibility concept in a round-robin based scheme, uFORM, and in a random-base scheme, uFPIM, to improve switching performance under nonuniform traffic patterns. The uFPIM scheme is based in the parallel iterative matching (PIM) scheme and shows the throughput improvement achieved with the captured frame concept. The uFORM scheme provides high performance under nonuniform traffic while keeping the high performance that round-robin schemes are known to have under uniform traffic.