AAL1 processing method and apparatus for parallelly executing sequence number processing and pointer comparison processing in ATM cell disassembly apparatus

An AAL1 processing apparatus for use in a cell disassembly apparatus comprising:

• sequence number processing means;
• pointer comparing means operable in parallel with said sequence number processing means on the assumption that a pointer is inserted in each of received ATM cells;
• means for determining the validity of the result of said pointer comparing means;
• and
• means for controlling data outputted to a STM multiplexer unit based on the result of said means for determining.

An AAL1 processing apparatus for use in a cell disassembly apparatus, comprising:

• status parameter holding means for storing status parameters corresponding to connection numbers for indicating a processing history of the preceding cell for each of the connection numbers added to each of ATM cells, said status parameters being stored as updatable;
• means for reading a status parameter corresponding to a connection number acquired when an ATM cell is inputted from said status parameter holding means based on the connection number and for setting said status parameter in each processing means in said AAL1 processing apparatus to recover a processing state of the ATM cell having said connection number;
• sequence number processing means for confirming the order of sequence numbers stored in AAL1 headers of respective received ATM cells based on a status parameter corresponding to the connection number to monitor each of the received ATM cells for cell loss and/or misinsertion;
• pointer comparing means, on the assumption that a pointer is inserted in each of the received ATM cells, for comparing a value of said pointer with the number of remaining bytes up to the head of a frame based on the status parameter corresponding to the connection number, said pointer comparing means operable in parallel with said sequence number processing means;
• determination means for determining whether or not a processing result in said pointer comparing means is valid based on said sequence number processing means and the status parameter corresponding to the connection number read from said status parameter holding means;
• frame length counting means for counting the number of remaining bytes up to the head of a STM frame to output a frame head signal;
• and
• output control means for controlling data to the outside of said AAL1 processing apparatus and output timing of said data based on a determination result of said determination means.