Encoder for use in asynchronous transfer mode systems

A communication system including:

• A. a source station for transmitting data, the source station including:
• i. a source station encoder for encoding a data packet and segmenting the data packet into fixed-sized cells, the encoder appending the result of the encoding to the packet before segmenting the packet,
• ii. means for transmitting the cells;
• and
• B. a destination station for receiving transmitted cells, the destination station including:
• i. a first encoder for encoding the data included in a received cell in accordance with a cyclic redundancy check code to produce an associated partial remainder;
• ii. means for appending the partial remainder to the received cell;
• iii. storage means for storing the cell and the appended partial remainder, the storage means linking the cell by pointers to previously stored cells associated with the same data packet;
• iv. means for determining if a cell is the last cell of a packet;
• v. means for retrieving the stored partial remainders associated with the cells belonging to a selected data packet once the last cell of the selected packet has been encoded by the first encoder;
• vi. a second encoder for manipulating the partial remainders associated with the retrieved cells to produce a packet remainder;
• and
• vii. comparison means for comparing the packet remainder with a predetermined pattern, the comparison means determining that the data packet is error-free if the remainder and the pattern match.

A system for determining if a data packet received in the form of cells contains errors, the system including:

• A. a first encoder for encoding the data included in a received cell in accordance with a cyclic redundancy check code to produce an associated partial remainder;
• B. storage means for storing the cell and the partial remainder, the storage means linking the cell and the partial remainder by pointers to previously stored cells and partial remainders associated with the same data packet;
• D. means for determining if a cell is the last cell of a packet;
• E. means for retrieving the stored partial remainders associated with the cells of a selected data packet once the last cell of the selected packet has been encoded by the first encoder;
• and
• F. a second encoder for manipulating the partial remainders associated with the cells to produce a packet remainder;
• G. comparison means for comparing the packet remainder with a predetermined pattern, the comparison means determining that the data packet is error-free if the remainder and the pattern match.