| 摘要 |
A traffic shaper (121 ) accommodates F5 maintenance cells of an ATM constant bit rate (CBR) virtual circuit without causing jitter or delay of the CBR traffic cells. Each virtual circuit is allocated two queues : a first queue (131) for enqueuing CBR traffic cells and a second queue (132) for enqueuing maintenance cells. Each virtual circuit is allocated twice its normal bandwidth on the transmission medium (120). A dequeue state machine (140) transmits contents of each first queue at twice the normal transmission rate during one half of each normal transmission interval of the queue's corresponding virtual circuit, and transmits content s of each second queue at twice the normal transmission rate during the other half of each normal transmission interval of the queue's corresponding virtual circuit. F5 cell transmissions are thus locked half- way between, and 180.degree. out of phase with, transmissions of sequential CBR traffic cells, and consequently introduce no jitter or delay, at th e expense of allocated bandwidth.
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