摘要:
In a policing arrangement for an ATM network, every incoming cell is stored in a cell buffer and a virtual path identifier (VPI) contained in the cell is extracted and translated to a corresponding one of a set of threshold values. Policing circuits of a matrix array are connected column by column for transferring a VPI in accordance with a read/write control circuit. Each policing circuit of the first column is uniquely responsive to a VPI of a particular value for storing the extracted VPI into a bridge memory, and this column has a greater number of policing circuits than any of the other columns of the array. In each column of the array, at least one of the policing circuits includes a cell counter for incrementing a cell count value in response to the VPI of every incoming cell and decrementing the cell count in response to a VPI read out of the bridge memory of the policing circuit. The cell count value is compared with the threshold value and a cell is discarded from the cell buffer when the cell count value exceeds the threshold value.
摘要:
A usage parameter control circuit for effecting a policing control in an ATM transmission network, comprising a time interval measuring unit for measuring a time interval between a current arrival time of a cell to be judged, and an arrival time of a cell which arrived a reference threshold number of cells before the currently arriving cell arrives; and a judging unit for judging whether or not the measured time interval is shorter than a reference threshold time interval, whereby a longer accessing time is allowed and the circuit construction has a flexible expandability.
摘要:
In an access network using optical switches, communications between an OLT and ONUs are established without a photoelectric conversion performed at an optical switching unit.The OLT controls the downlink optical switch SW(DOWN) to sequentially select each ONU in slots arranged in a discrete manner, and transmits a Discovery Gate message. Upon receipt of the Discovery Gate message, each ONU consecutively transmits Register Request messages. The uplink optical switch SW(UP) sequentially switch signals from ONU#1 through ONU#128 in the slots arranged in a discrete manner, and outputs the signals to the OLT, Some of the Register Requests transmitted from the respective ONUs pass through the SW(UP), and reach the OLT. Based on the received Register Requests, the OLT determines the timing of transmission for the ONUS, and notifies the ONUS of the timing of transmission through a Gate message.
摘要:
Nodes notify each other of the availability situation of links, whereby the link availability situation is reflected in the network topology information held by each node. The designated routing information of a packet which arrives at a local node for subsequent transfer is updated on the basis of the topology of a network from which the following have been removed: any nodes which a packet arriving at the local node for subsequent transfer has already passed; any links directly connected to such nodes; and any congested or faulty links.
摘要:
In an input cell policing method in a network of an asynchronous transfer mode, according to information contained in a header field of each input cell, a group to which the cell belongs is identified. For each group, there are set a plurality of time frames having a predetermined length and mutually different phases to count the number of input cells in each time frame period. For each time frame, the count value of input cells is compared with a predetermined threshold value. An input cell for which the count value exceeds the threshold value in either one of the time frames is assumed to be an excess cell. The excess cell is discarded or a violation mark is added thereto.
摘要:
An ATM switch in which the throughput is improved by the simplified arbitration scheme and circuit configuration. This ATM switch uses a matrix type switch formed by N input lines for transmitting the cells read out from the input buffers, M output lines for transmitting the cells to be written into the output buffers, and N.times.M crosspoints located at intersections of the input lines and the output lines, where each crosspoint at an intersection of one input line and one output line carries out an arbitration operation in which a cell arriving from an upper stream side of that one output line is passed to a lower stream side of that one output line with a higher priority than a cell arriving from that one input line, and tile cell arriving from that one input line is transferred to the lower stream side of that one output line only when there is no cell arriving from the upper stream side of that one output line.