Abstract: A digital information mapper and method for mapping sequences of information characters into a SONET (synchronous optical network) payload in such a manner that there can be an arbitrary mixture of control and/or data values in those sequences. Each information character comprises 9 bits consisting of an 8 bit information byte, being either a control byte or a data byte, and one octet type bit identifying the byte as control or data. A processor applies a mapping algorithm of a mapping module to the input information characters. The mapping algorithm is applied to sequences of eight input information characters, the algorithm being operable to map the information bytes of each sequence of eight information characters to eight of a sequence of nine contiguous SPE octets. The algorithm then maps the octet type bits for the eight mapped information bytes of the character sequence to the ninth octet of the contiguous SPE octets of the SPE octet sequence.

Abstract: A method and apparatus are provided for flexible time-division multiplexing, and demultiplexing, of serial line data, from 1-n client lines, based on the SONET standard (e.g. OC-48 or OC-192) whereby a predetermined and reconfigurable number of STS-1s are allocated to each client. A multiplexer includes 1 to n mappers for mapping the data of 1 to n clients, according to a predetermined bandwidth allocation, to an N×STS-1 SONET payload, each mapper using y STS-1s where y is 0 to N, the y STS-1s being selected on a sequential or non-sequential concatenation basis from the N STS-1s. Each mapper maps the data of one client and each allocated STS-1 is allocated to one client and the total number of STS-1s allocated to the clients is less than or equal to N. An aggregator aggregates the mapped data into a composite STS payload comprising N STS-1s. A bandwidth allocation receiver receives the bandwidth allocation.

Abstract: A digital information mapper and method for mapping sequences of information characters into a SONET (synchronous optical network) payload in such a manner that there can be an arbitrary mixture of control and/or data values in those sequences. Each information character comprises 9 bits consisting of an 8 bit information byte, being either a control byte or a data byte, and one octet type bit identifying the byte as control or data. A processor applies a mapping algorithm of a mapping module to the input information characters. The mapping algorithm is applied to sequences of eight input information characters, the algorithm being operable to map the information bytes of each sequence of eight information characters to eight of a sequence of nine contiguous SPE octets. The algorithm then maps the octet type bits for the eight mapped information bytes of the character sequence to the ninth octet of the contiguous SPE octets of the SPE octet sequence.

Abstract: This invention relates to a method and apparatus for controlling the flow of fiber channel (FC) data frames from a fiber channel link to a metropolitan area link of lesser bandwidth (a synchronous optical network (SONET)). The release of each data unit by a data source for transport onto the first channel is governed by a credit-based protocol whereby one data unit is released upon the provision of one credit unit. A first marker identifies a high limit H of the buffer at which a first condition occurs, H being less than N and the first condition applying when the number of data units in the buffer is greater than H. A second marker identifies a low limit L of the buffer at which a second condition occurs, L being less than H and the second condition applying when the number of data units in the buffer is less than L. A credit unit owed counter O counts the number of credit units which become owed to the data source when the second condition applies.

Abstract: A method and apparatus are provided for flexible time-division multiplexing, and demultiplexing, of serial line data, from 1-n client lines, based on the SONET standard (e.g. OC-48 or OC-192) whereby a predetermined and reconfigurable number of STS-1s are allocated to each client. A multiplexer includes 1 to n mappers for mapping the data of 1 to n clients, according to a predetermined bandwidth allocation, to an N×STS-1 SON ET payload, each mapper using y STS-1s where y is 0 to N, the y STS-1s being selected on a sequential or non-sequential concatenation basis from the N STS-1s. Each mapper maps the data of one client and each allocated STS-1 is allocated to one client and the total number of STS-1s allocated to the clients is less than or equal to N. An aggregator aggregates the mapped data into a composite STS payload comprising N STS-1s. A bandwidth allocation receiver receives the bandwidth allocation.

Abstract: A digital information mapper and method for mapping sequences of information characters into a SONET (synchronous optical network) payload in such a manner that there can be an arbitrary mixture of control and/or data values in those sequences. Each information character comprises 9 bits consisting of an 8 bit information byte, being either a control byte or a data byte, and one octet type bit identifying the byte as control or data. A processor applies a mapping algorithm of a mapping module to the input information characters. The mapping algorithm is applied to sequences of eight input information characters, the algorithm being operable to map the information bytes of each sequence of eight information characters to eight of a sequence of nine contiguous SPE octets. The algorithm then maps the octet type bits for the eight mapped information bytes of the character sequence to the ninth octet of the contiguous SPE octets of the SPE octet sequence.