Abstract: An ATM connection is a virtual communication path specified by VPI/VCI. A plurality of ATM connections that are directed to the same output line is defined as an ATM connection group. A connection UPC (Usage Parameter Control) facility is provided for each of the ATM connections and a connection group UPC facility is provided for the ATM connection group. The connection UPC facilities and the connection group UPC facility are operated in either the monitor mode or the control mode. In the monitor mode, when the rate of flow of packets into a network exceeds a threshold, a control unit is informed of it, but cells are allowed to enter the network as they are. In the control mode, when the rate of flow of cells into the network exceeds the threshold, cells the flow rate of which exceeds the threshold are discarded.

Abstract: For both a bandwidth-guaranteed connection call and a non-bandwidth-guaranteed connection call together, with respect to the bandwidth-guaranteed connection call, a schedular allocates the number of time slots which correspond to a required bandwidth to the bandwidth-guaranteed connection call from among the N time slots that constitute one period and so controls as to transmit an ATM cell at an allocated time slot. The non-bandwidth-guaranteed call transmitting unit transmits an ATM cell of a non-bandwidth-guaranteed connection call at a time slot which is not allocated to any bandwidth-guaranteed connection call. A congestion/normal state monitoring unit sets in advance a queue length which is regarded as the occurrence of a long-term congestion in a queuing buffer and compares the actual queue length with the preset queue length so as to detect the occurrence of a long-term congestion.

Abstract: A plurality of switching modules arrayed in a plurality of columns and in at least one row switch over paths in accordance with path data contained in cells to transfer inputted data to a target line on the cell-unit. One or more path switching units are provided between two adjacent columns of switching modules among plural columns of switching modules and switch paths between the respective switching modules, disposed in a side-by-side relationship in a row direction, of one column of switching modules of the two adjacent columns of switching modules and the respective switching modules, disposed in the side-by-side relationship in the row direction, of the other column of the two adjacent columns of switching modules.

Abstract: A cell buffer is provided for storage of cells for each quality class. A counter is provided for each cell buffer. A threshold value which regulates the respective readout interval is set for each quality class. The count of the counter for each quality class is increased by 1 for each time slot. When the count for a certain quality class reaches the threshold value, if a cell is stored in the cell buffer for that quality class, that cell is read out and output, and, at the same time, the count is decreased by the threshold value. When the count for a certain quality class reaches the threshold value, if a cell is not stored in the cell buffer for that quality class, the count is left unchanged.

Abstract: In an ATM switching system responsive to a call setup request from each of B-ISDN terminals, a band for an accepted call is estimated in accordance with fuzzy decision on the basis of the fact that the network traffic characteristics can be determined empirically. Therefore, it is possible to estimate the band without any complicated band estimation calculations, improve the call acceptance processing response speed, and further improve the availability efficiency of the network transmission line. In the consequents of the fuzzy rules in particular, the respective band estimation values are represented by the respective input functions, or particularly by the linear couplings coupled by predetermined linear parameters of respective inputs, thus improving the descriptive capacity of the rules.

Abstract: An ATM including both a bandwidth-guaranteed connection call and a non-bandwidth-guaranteed connection call together, with respect to the bandwidth-guaranteed connection call, a scheduler 21 allocates the number of time slots which correspond to a required bandwidth to the bandwidth-guaranteed connection call from among the N time slots which constitute one period and so controls as to transmit an ATM cell at an allocated time slot. A non-bandwidth-guaranteed cell transmitting element 31 transmits an ATM cell of a non-bandwidth-guaranteed connection call at a time slot which is not allocated at any bandwidth-guaranteed connection call. A congestion/normal state monitoring element 121 sets in advance a queue length which is regarded as the occurrence of a long-term congestion in a queuing buffer 111, and compares the actual queue length with the preset queue length so as to detect the occurrence of a long-term congestion.

Abstract: A connection admission control method for allocating many calls to a transmission line while guaranteeing the quality of service such as the cell loss ratio, where an average cell rate/peak cell rate comparator judges that a call requesting admission has a variable-speed traffic property when the average cell rate Ra and the peak cell rate Rp which are declared by the user are different. A traffic class judging portion determines the traffic class to which the call belongs on the basis of the peak cell rate. A required bandwidth calculator obtains the required bandwidth for guaranteeing the quality on the basis of the sum of the average cell rate of the call requesting admission and the average cell rates of all the calls that belong to the traffic class and that are already allocated to a transmission line, and outputs the calculated bandwidth as the estimated bandwidth.

Abstract: The present invention is designed such that the communication quality of a currently connected normal call is deteriorated and the transmission of the normal call is delayed in a network when an emergent call is set. As a result, the required bandwidth of the emergent call is successfully reserved. Furthermore, the present invention is designed such that a deteriorated normal call is detoured to a detour circuit to improve the communication quality of the normal call. In the detouring process, one or more detour circuits are managed for each normal call so that the possibility of a successful detour to a detour circuit can be raised. Additionally, in the normal call detouring process, a plurality of detour circuits guarantee a normal call its communication quality even if a single detour circuit is not enough to meet the required bandwidth of a normal call.

Abstract: In an ATM switching system responsive to a call setup request from each of B-ISDN terminals, a band for an accepted call is estimated in accordance with fuzzy decision on the basis of the fact that the network traffic characteristics can be determined empirically. Therefore, it is possible to estimate the band without any complicated band estimation calculations, improve the call acceptance processing response speed, and further improve the availability efficiency of the network transmission line. In the consequents of the fuzzy rules in particular, the respective band estimation values are represented by the respective input functions, or particularly by the linear couplings coupled by predetermined linear parameters of respective Inputs, thus improving the descriptive capacity of the rules.