VC merging for ATM switch

A method of operating an Asynchronous Transfer Mode (ATM) switching device, the method comprising:

• applying incoming cells to a switch core from a plurality of incoming VC channels, the switch core receiving, on the plurality of incoming VC channels, cells having a corresponding plurality of VC identifiers;
• receiving, at an egress port connected to the switch core, cells having the corresponding plurality of VC identifiers and which are applied to a same outgoing VC channel, and at the egress port performing the steps of:
• storing the incoming cells in a plurality of pre-merge VC queues in accordance with their incoming VC channel;
• making a determination when one of the pre-merge VC queues has a completed packet of cells therein;
• and, in accordance with the determination,
• entering the packet of cells into a merge VC queue associated with the outgoing VC channel;
• and
• applying the completed packets of cells from the merge VC queue to a single outgoing link connected to the merge VC queue whereby all cells entered into the merge VC queue are applied to the single outgoing link.

An Asynchronous Transfer Mode (ATM) switching device comprising:

• a switch core connected to a plurality of incoming VC channels;
• an egress port connected to receive cells from the switch core, the egress port comprising:
• a plurality of pre-merge VC queues into which cells received from the switch core are stored in accordance with their incoming VC channel;
• at least first and second merge VC queues;
• a merge controller which determines when one of the pre-merge VC queues has a completed packet of cells therein, and wherein said merge controller determines whether to enter the packet of cells in the first or second merge VC queue and thereafter enters the packet of cells into the appropriate one of the merge VC queues so that completed packets of cells in the plurality of pre-merge VC queues are merged into a single outgoing link connected to the appropriate merge VC queue.

A method of operating an Asynchronous Transfer Mode (ATM) switching device, the method comprising:

• applying incoming cells to a switch core from a plurality of incoming VC channels;
• at an egress port connected to receive cells from the switch core:
• storing the incoming cells into a plurality of pre-merge VC queues in accordance with their incoming VC channel;
• providing first and second merge VC queues in the egress port;
• making a determination when one of the pre-merge VC queues has a completed packet of cells therein;
• determining whether to enter the packet of cells in the first merge VC queue or the second merge VC queue;
• entering the packet of cells into the first merge VC queue based upon said determining step;
• and
• applying the completed packets of cells from the first merge VC queue to a single outgoing link connected to the first merge VC queue.