摘要:
In a first UPC, a PCR is set as a monitor rate for each connection. If a transfer rate of a cell exceeds the PCR set for the connection, the cell is discarded. In a second UPC, an ACR is set as a monitor rate for each connection. If the transfer rate of the cell exceeds the ACR set for the connection, a lower priority is assigned to that cell. Additionally, with a configuration where one UPC monitors a varying rate, a parameter change process is controlled by obtaining a time between a passage time of a detected B-RM cell and an arrival of a user cell and comparing the obtained time with maximum and minimum delay standard values. A parameter table including some parameters is provided. A header of an arrived cell in a forward direction is extracted, and it is determined whether or not the arrived cell is a violation cell using the leaky bucket algorithm, etc. If the arrived cell is a violation cell, it is discarded. An RM cell in a backward direction is received and extracted, and the parameter table is updated by calculating the minimum cell interval, etc. based on data included in a payload of the RM cell.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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. An estimated bandwidth calculator for calls having a variable-speed traffic property calculates the estimated total bandwidth for all the traffic classes, and a call admission judging portion judges whether or not there is a vacant bandwidth in the transmission line which is necessary for accepting the call requesting admission with consideration of the calculated estimated total bandwidth and the physical bandwidth, and accept the call if vacant bandwidth exists, otherwise reject the call.
摘要:
Control messages for securing a communication quality are exchanged via a dedicated connection within an ATM network when a sending terminal in an IP network delivers data to a receiving terminal in another IP network via the ATM network. A resource reservation message sent from the receiving terminal is parsed by a boundary device located at the boundary between the IP and the ATM network, and a data transfer connection is established within the ATM network based on the information of the resource reservation message.
摘要:
A boundary apparatus on the transmission side provided on the boundary between an IP network accommodating a transmitting terminal and an ATM network separates the requests for bandwidth which are received from receiving terminals via boundary apparatuses on the reception side into a plurality of groups on the basis of a required bandwidth, establishes a point-multipoint connection between the boundary apparatus on the transmission side and each of the boundary apparatuses on the reception side for each group, and transmits the data from the transmitting terminal to each of the receiving terminals via the connection. When there is a change in the number of the requests for bandwidth due to the delivery of a new request for bandwidth or the interruption of a flow of requests, the boundary apparatus on the transmission side calculates the effective bandwidth allocation ratio of the group in which there is a change in the number of the requests for bandwidth, and if the effective bandwidth allocation ratio is not more than a preset value, the boundary apparatus separates the requests belonging to the group into two groups, and establishes a connection for each group.
摘要:
In an ATM switching system, an ABR service is implemented with a specific ABR control capability. A subscriber line processing device includes calculating a turnaround delay time of a cell, based on a period during which the cell doubles back at a terminal. A switch or a demultiplexer capable of detecting congestion. A rate calculator calculates a transmission rate corresponding to an output channel, and writes the calculated rate to the cell. A rate changer changes the transmission rate according to congestion. The rate changer counts the number of communicating connections. Then the number of communicating connections which should exist in a certain predetermined period is estimated based on the counted number of communicating connections. A coefficient is determined based on the estimated number of communicating connections and an actual number of communicating connections, and a next estimated value is estimated using the coefficient.