Cascade Communications Corporation

Kurt A Melden

Gregory S Goss

A method and apparatus are disclosed for multicasting through a single physical port in a switch, i.e., logical multicasting. An incoming cell is logically multicast by providing a first copy of the cell to the desired output port and providing a second copy of the cell to a loop-back element which includes standard input and output ports dedicated to loop-back operation. The cell provided to the loop-back element is subsequently provided to the desired output port such that the first and second copies of the cell are serially transmitted from the single desired output port. Further, the cell provided to the loop-back element may be repeatedly copied, provided to the loop-back element, and provided to the desired output port. Thus, the incoming cell may be transmitted through a single output port as many times as is desired. When utilized in conjunction with a switch configured for unicast operation, multicast type capability can be provided in the unicasting switch by logically multicasting from the multicasting switch to the unicasting switch.

Logical multicast from a switch configured for spatial multicast

Method and apparatus are disclosed for maintaining operational and statistical information in a high speed network switch for each of a plurality of supported connections. A high speed array is provided which includes a plurality of high speed registers for each of a plurality of connections supported by the switch. Upon receipt of a cell/frame, a connection identifier is generated to identify the connection within the network switch and the connection identifier is stored in an index register. The connection identifier stored within the index is used to select a plurality of registers within the high speed register array of registers pertaining to the specified connection. Information pertaining to each received cell/frame is generated upon receipt of the cell or retrieved from the respective cell header and is employed to generate an operand for each of the plurality of registers addressed by the connection identifier. Operands may allow for the clearing, setting, incrementing, decrementing or maintenance of the register contents. Each of the plurality of registers identified by the connection identifier is updated in parallel within the time frame associated with the receipt of a frame/cell.

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Westborough, MA, United States of America

Kurt A Melden