摘要 |
<p>Methods and apparatus for processing cells in an asynchronous transfer mode (ATM) communication system. An ATM cell processor implements a 'bubble' count technique which efficiently accommodates multiple layers of scheduling requests and/or external sources. In the cases of multiple layers of scheduling requests, first primary scoreboard (100) and second primary scoreboards are provided for scheduling/servicing of, for example, higher and lower priority traffic, higher and lower cell rate traffic, or externally and internally generated traffic, respectively. A bubble count is maintained for the second scoreboard, and the count is incremented each time the first scoreboard is serviced and decremented each time an idle slot is encountered on the second scoreboard but not queued for transmission. Scheduling requests for the second scoreboard are then made at a target time plus the bubble count.</p> |