Abstract: A method and apparatus is disclosed for temporarily deferring transmission of frames to a destination in a data switch. When a request for transmission of a frame to the destination port is received, the congestion status of that destination is determined. If the destination is congested, the frame is stored in a deferred queue. When the status of a destination changes from congested to non-congested, the deferred queue is examined to see if any deferred frames can now be forwarded to their destination. While examining the deferred queue, incoming frames are placed on a backup queue. When the deferred queue is fully analyzed, the backup queue is emptied by either sending those frames to their destination or storing the frames in the deferred queue. While examining the deferred queue, the congested states of the destinations are not allowed to change from congested to non-congested.

Abstract: A method and apparatus is disclosed for temporarily deferring transmission of frames to a destination in a data switch. When a request for transmission of a frame to the destination port is received, the congestion status of that destination is determined. If the destination is congested, the frame is stored in a deferred queue. When the status of a destination changes from congested to non-congested, the deferred queue is examined to see if any deferred frames can now be forwarded to their destination. While examining the deferred queue, incoming frames are placed on a backup queue. When the deferred queue is fully analyzed, the backup queue is emptied by either sending those frames to their destination or storing the frames in the deferred queue. While examining the deferred queue, the congested states of the destinations are not allowed to change from congested to non-congested.

Abstract: A switch segments variable length frames into cells for transmission over a cell-based switch fabric and handles rate differences between the input data rate and the switch fabric data rate. The fabric handles multiple cell packets by maintaining a switch path until a certain number of cells are transmitted as indicated in a length field in the first data cell. The first cell contains a full data payload, and a length field value sufficient to handle a maximum length frame. Subsequent cells can contain less than a full data payload, with the number of valid bytes in the cell being indicated in the length field. The last cell used to segment the frame contains an end of frame indicator. The indicator signals the destination port side of the switch to terminate the packet path in the switch fabric prematurely—before the number of cells indicated in the first data cell.