Abstract: A method and apparatus for prioritizing ATM cells within time transmission slots is disclosed. The present invention takes cells which have been prioritized by traditional priority circuitry and adds to them information regarding the need to begin transmitting cells in the current time slot in order to ensure that a list of cells which must be transmitted by a future time slot can all be transmitted timely. If no list of cells in a future time slot mandate immediately transmission in the current time slot, a cell from the standard prioritization buffer will be transmitted. If, on the other hand, a subsequent slot contains so many entries that one of its cells must be transmitted in the current slot in order to ensure that all cells in the list are transmitted before their time deadline, one of the cells from the subsequent time slot list will be transmitted in lieu of the standard priority cell of the current slot.

Abstract: A packet-based transmission system is disclosed in which resource management packets containing cell rate information are processed at a single ABR server. The server receives forward resource management packets and routes them without modification to their destination. The server also receives reverse resource management packets which it processes by updating their corresponding cell rate information based, for example, on cell rate information received from the forward cells.

Abstract: A new, efficient approach to ATM connection table lookup minimizes the number of tables and memory lookups through use of hash coding and binary table search techniques. The virtual connection information associated with an incoming ATM cell is hash coded. The hash code provides a compressed representation of the virtual connection information--allowing the address space of a table accessed based on the hash code to be much smaller than the maximum number of possible virtual connection combinations that can be encoded in the ATM cell header without restricting the set of possible virtual connection combinations. A binary search based on the cell's virtual connection information can be used to efficiently select, from plural records accessed based on the hash code, the particular search record corresponding to the cell's connection.

Abstract: An Asynchronous Transfer Mode (ATM) switching device handles active and passive leaves. For a multicast connection being routed through the switching device, there is set up both a passive leaves queue (PLQ) for each physical output link and a leaf table for each leaf of the multicast connection. The leaf tables are added and removed for each connection on the fly as each leaf is added or removed. For a passive leaf of the multicast connection, the leaf table for the passive leaf is linked to an appropriate one of the passive leaves queues. However, upon reception of a cell from a switch core, the appropriate one of the passive leaves queues is activated by being linked to an activation queue (AQ). Thereafter a pointer is set, in an active leaves queue (ALQ), to the leaf table indicated in the appropriate passive leaves queue (PLQ). There is an active leaves queue for each physical output.