Shared buffer memory type ATM communication system and method with a broadcast facility

Claim 1

A communication system having a plurality of incoming lines for receiving input cells of asynchronous transfer modes (ATM) including normal cells and broadcast cells and a plurality of outgoing lines for outputting said input cells input from the incoming lines, said system outputs said input cells to the outgoing lines in accordance with header information of said input cells, and outputs each of said normal cells to one of said plurality of outgoing lines and each of said broadcast cells to at least two of said plurality of outgoing lines, said system comprising: input interface means provided for each of said incoming lines, for adding internal routing information, which is uniquely set in the inside of said communication system, to a header part of each of said input cells; buffer memory means for storing temporarily said input cells; writing control means for storing said input cells in said buffer memory means so as to form a plurality of list structures corresponding to the respective internal routing information, said list structures including one broadcast cell list structure for chaining said broadcast cells together, each of said broadcast cells in said one broadcast cell list structure has a pointer which indicates a cell to be output next, and a plurality of normal cell list structures for chaining said normal cells other than said broadcast cells together, said normal cell list structures corresponding to said outgoing lines; reading control means for reading out said normal and broadcast cells from said plurality of list structures formed in said buffer memory means to distribute said normal and broadcast cells thus read to said outgoing lines; and output interface means provided for each of said outgoing line, for converting the header part of a cell read out from said buffer memory means by said reading control means into a header format which is used in a network connected to said outgoing lines of said communication system, said reading control means comprises: table means for storing a bit pattern for specifying the outgoing lines, through which broadcast cell of interest is to be output, in correspondence to the internal routing information of the broadcast cell, and broadcast control means for reading out broadcast destination specifying information corresponding to the internal routing information of the broadcast cell located at a head part of said one broadcast cell list structure, selecting, on the basis of said broadcast destination specifying bit pattern thus read out, one of said plurality of list structures every outgoing line, and reading out the normal cell or the broadcast cell located at a head part of said list structure thus selected, said broadcast control means serving to read out the same broadcast cell repeatedly from said one broadcast cell list structure to the associated outgoing lines for a period of time until a next broadcast destination specifying bit pattern is read out from said table means.

Claim 15

A method in a communication system having a plurality of incoming lines for receiving input cells of asynchronous transfer modes (ATM) including normal cells and broadcast cells and a plurality of outgoing lines for outputting said input cells input from the incoming lines, said system outputs said input cells to the outgoing lines in accordance with header information of said input cells, and outputs each of said normal cells to one of said plurality of outgoing lines and each of said broadcast cells to at least two of said plurality of outgoing lines, said method comprising the steps of: storing said input cells in a buffer to form a plurality of list structures corresponding to the respective internal routing information included in a header part of each of said input cells, said list structures including one broadcast cell list structure for chaining said broadcast cells together, each of said broadcast cells in said one broadcast list structure has a pointer which indicates cells to be output next, and a plurality of normal cell list structures for chaining said normal cells other than said broadcast cells together, said normal cell list structures corresponding to said outgoing lines; and reading out said normal and broadcast cells from said plurality of list structures formed in said buffer to distribute said normal and broadcast cells thus read to said outgoing lines; said reading step comprises the steps of: storing a bit pattern for specifying the outgoing lines, through which a broadcast cell of interest is to be output, in correspondence to the internal routing information of the broadcast cell, reading out broadcast destination specifying information corresponding to the internal routing information of the broadcast cell located at a head part of said one broadcast cell list structure, selecting, based on said broadcast destination specifying bit pattern thus read out, one of said plurality of list structures every outgoing line, and reading out the normal cell or the broadcast cell located at a head part of said list structure thus selected, wherein said step of read out the normal cell or the broadcast cell located at a head part of said list structures is performed such that when a broadcast cell is read out the same broadcast cell is read out repeatedly from said one broadcast cell list structure to the associated outgoing lines for a period of time until a next broadcast destination specifying bit pattern is read out.

Claim 16

A method in a communication system having a plurality of incoming lines for receiving input cells of asynchronous transfer modes (ATM) including normal cells and broadcast cells and a plurality of outgoing lines for outputting said input cells input from the incoming lines, said system outputs said input cells to the outgoing lines in accordance with header information of said input cells, and outputs each of said normal cells to one of said plurality of outgoing lines and each of said broadcast cells to at least two of said plurality of outgoing lines, said method comprising the steps of: storing said input cells in a buffer to form a plurality of list structures corresponding to the respective internal routing information included in a header part of each of said input cells, said list structures including one broadcast cell list structure for chaining said broadcast cells together, each of said broadcast cells in said one broadcast list structure has a pointer which indicates cells to be output next, and a plurality of normal cell list structures for chaining said normal cells other than said broadcast cells together, said normal cell list structures corresponding to said outgoing lines; and reading out said normal and broadcast cells from said plurality of list structures formed in said buffer to distribute said normal and broadcast cells thus read to said outgoing lines; said reading step comprises the steps of: storing a bit pattern for specifying the outgoing lines, through which a broadcast cell of interest is to be output, in correspondence to the internal routing information of the broadcast cell, reading out broadcast destination specifying information corresponding to the internal routing information of the broadcast cell located at a head part of said one broadcast cell list structure, selecting, based on said broadcast destination specifying bit pattern thus read out, one of said plurality of list structures every outgoing line, and reading out the normal cell or the broadcast cell located at a head part of said list structure thus selected, wherein said step of read out the normal cell or the broadcast cell located at a head part of said list structures is performed such that when a broadcast cell is read out the same broadcast cell is read out repeatedly from said one broadcast cell list structure to the associated outgoing lines for a period of time until a next broadcast destination specifying bit pattern is read out.