Abstract: A method of identifying a segment and end-to-end OAM flow VPC context table for one of a plurality of VCCs corresponding to the VPC. Each VCC has a context table. Each VCC context table has a pointer. The pointer contains the address of the context table for the segment and end-to-end OAM flow VPC. Provisioned connections supported by the ATM switching system are repeatedly scanned. If a VCC has an active F4-to-F5 OAM process, the pointer is extracted from that VCC's context table, identifying the context table of the corresponding segment and end-to-end OAM flow VPC. If the VPC is in the VP-AIS alarm state, the current VCC outputs a VCC-AIS cell. A continuity check is repeatedly performed by updating the appropriate F4 OAM connection context table whenever a VCC cell is received on a corresponding F5 connection, preventing the F4 connection from raising a continuity check alarm.

Abstract: A method of determining an error detection code (EDC) on incoming data which includes a reserved bit field, comprising applying the incoming data to inputs of both an input data CRC (IDC) calculator and to an input data and reserved field CRC (IDRC) calculator, calculating the EDC on successive input data words and recursively updating the EDC in both the IDC and IDRC calculators, selecting a payload of the input data as a system output signal for all payload words, and subsequently selecting a output EDC word from the IDRC calculator in a time immediately following a final payload word which contains the reserved field.

Abstract: A method and apparatus for traffic control in an ATM-based network is provided to avoid congestion of traffic flows and false identifications of conforming and non-conforming cells.

Abstract: A device for identifying cells as either conforming or non-conforming in a cell-based transmission system, which includes an n-bit word-length counter having an input coupled to a source of clock pulses, a parallel n-word gate coupled to a parallel output of the n-bit word length counter and having a gate input coupled to a source of cell arrival signals. A processor is coupled to an output of gate having a first comparer for comparing TAT and t.sub.a (k), a second comparer for comparing t.sub.a (k)[n-1] with zero and t.sub.a (k-1)[n-1] with 1, a setting device for setting TAT=t.sub.a (k) in the event that either of the comparisons in the first and second comparers are true. A third comparer is provided for comparing TAT and t.sub.a (k)+L and if TAT is less than or equal to t.sub.a (k)+L, an indexing device for indexing TAT by I and declaring the cell conforming, and an output device for declaring the cell non-conforming if TAT is greater than t.sub.a (k)+L.