摘要:
Specific ABR control capability for implementing an ABR service in an ATM switching system. A subscriber line processing device has a capability for calculating a turnaround delay time of a cell, based on a period during which the cell loops back at a terminal and returns. A switch or demultiplexer has a capability for 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 suitably changes the transmission rate according to the degree of occurrence of congestion. Additionally, the rate changer counts the number of communicating connections. At this time, the number of communicating connections which should exist in a certain predetermined period is estimated based on the counted number of communicating connections, which is counted in a period shorter than the predetermined period according to a predetermined method. Additionally, a coefficient is determined based on the number of communicating connections so estimated and an actual number of communicating connections, and a next estimated value is estimated to be a more suitable value using the coefficient.
摘要:
A call admission control system in an asynchronous transfer mode exchange includes a unit for describing attribute parameters of a call from the subscriber terminal; a unit for calculating, based on the attribute parameters, the average and the dispersion of the traffic speeds of the call; a unit for managing data of the average and the dispersion on each output route and data relating to each subscriber; and a unit for calculating the total average and the total dispersion of the data speeds on the selected output route; and a unit for calculating prediction values of cell abandon rate and end-to-end delay based on the average and the dispersion on the selected output route calculated by the total average and dispersion calculating unit, and for comparing the prediction values with the required service quality of cell discard rate and end-to-end delay, for determining whether or not the requesting call may be connected.
摘要:
A video quality monitoring method includes a distribution server measuring first video quality index values according to a full-reference method by comparing a video, distributed from the distribution server to a client through a network, with a degraded video, generated by causing multiple scenarios of quality degradation due to the network in the video in a pseudo manner, creating characteristic data of first quality degradation values, obtained by causing the quality degradation to vary with the scenarios at regular intervals, and the first video quality index values corresponding to the respective scenarios, and transmitting the characteristic data to the client; and the client measuring a second quality degradation value in the video distributed through the network, and calculating a second video quality index value, equivalent to a value according to the full-reference method, of the distributed video from the measured second quality degradation value and the characteristic data.
摘要:
There is disclosed a transmitting system which is capable of recovering a fault efficiently, thereby improving transmission quality. When a fault has occurred, a fault message-sending section notifies a fault message including information of a detected location of occurrence of the fault to other devices. A relay/transfer section carries out label switching operation on a packet having a label added thereto and relay/transfer of the packet. The integer calculation section performs a function operation based on flow information of an input packet to calculate one integer corresponding to one input packet. A path-setting section classifies the calculated integer into one of sections divided by boundary values and sets the section as a path for transferring the input packet. Further, the path-setting section adjusts the boundary values, when a fault message is received, or depending on the state of communication. An ingress edge transfer device adds a label to a packet for transferring the packet via the set path.
摘要:
The present invention provides a traffic information collecting device and method. A node in a communication network collects a first traffic information of a first link connected to an own node. And also the node receives second traffic information of second links connected to the other nodes. The second traffic information is transmitted from the other nodes. The node stores the first and second information. In consequence, the node can be informed of the conditions of the traffic of each link in the communication network based on the stored information. As the result, it becomes possible to control the load sharing in correspondence to the conditions of the traffic.
摘要:
A feedback control apparatus whereby the traditional single control loop for available bit rate (ABR) connections is segmented into a plurality of loops that are handled in a mutually related manner for better responsiveness of ABR connection feedback control. Three control loops are illustratively formed: a closed upward feedback control loop between a source end system and a virtual destination-link unit (VD-L) for an ABR connection, a downward control loop between a destination end system and a virtual source-link unit (VS-L) for the ABR connection, and an intra-switch feedback control loop between an upstream virtual source-internal unit (VS-I) and a downstream virtual destination-internal unit (VD-I) for the ABR connection.
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:
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.
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.