Abstract:
An ATM (asynchronous transfer mode) exchange has a buffer for system #0 and a buffer for system #1 providing P-MEM's for storing data including an A bit and for a VCI/VPI currently in use is set to "1'. Upon detecting a switchover between the systems, every B bit is reset to "0". When the exchange while changing from a master to a slave receives a cell having a slave indication and while changing from a slave to a master it receives a cell having a master indication, respective systems rewrite B bits for VCI/VPI's of respective cells to "1". In the meantime, each of the P-MEM's calculates exclusive "OR" operations between the A bit and the B bit for every VCI/VPI, and further obtains a disjunction among all the exclusive "OR" operations thus obtained. Then, when both P-MEM's obtain "0" for their respective disjunctions, cells are read out from one of the buffers in the system changing from a slave to a master. This enables the ATM exchange having a switch duplexed by mutually asynchronous active and backup systems to switchover the systems without causing a cell to be duplicated or lost.
Abstract:
An ATM transmission system transmits cell-formatted data in an asynchronous transfer mode, and aims at conducting an online path route test in the system. If one path route only is established in the system, then one or more valid cell detecting units for detecting, upon receipt of a cell enable signal indicating that a valid cell to pass through the path route has been sent, the arrival of a valid cell are provided at an optional point including an ATM switch in the path route so that the path route can be partially or entirely validity-checked. If plurality of valid path routes are established, the system provides, in addition to the valid cell detecting units, a virtual path identifier and virtual channel identifier comparing unit for comparing values of the VPI and VCI stored therein with values of a VPI and a VCI added to an arriving cell, and a path route validity check unit for partially or entirely validity-checking a path route in the ATM transmission system.
Abstract:
An in-service activator for a broadband exchanger has a dual system structure, in which a first system and a second system form a dual pair. The first system and the second system in the dual pair each has at least one [1] channel converter and a switcher. A channel converter stores channel setting information for use in routing a cell inputted from a line, and outputs the cell inputted from the line by attaching the channel setting information to the cell. The switcher switches a cell outputted from a channel converter. The interfacer stores, in a channel converter of a to-be-activated standby system in the dual pair, the channel setting information read from the corresponding channel converter of an act system in the duplex pair.
Abstract:
A main processor assigns originated-call processings to each of a plurality of call processors in the sequence of call originations according to the first principle of this invention. A switching state controller collects usage information about a plurality of buffers composing the switching network in the ATM exchanger. The call processors to which call processings are assigned perform the call processings based on the content of switching state controller a main processor assigns a call processing for an originated call to one of a plurality of call processors by referring to the call processing assignment table memory with the virtual channel identifier corresponding to an originated call according to the second principle of this invention thus, call processing loads are distributed among call processors.
Abstract:
An ATM exchange which is comprised of a multistage cascade connection of ATM switches of self-routing module structures which are provided with a plurality of outgoing lines and incoming lines, wherein it provides at the output side and the input side of the ATM switches output side conversion interfaces and input side conversion interfaces both for connection of adjoining ATM switches and uses optical cables to connect the output side interfaces and input side interfaces facing thereto. By this, it is possible to maintain the correct exchange operation even if the length of the transfer lines (outgoing lines and incoming lines) laid between ATM switches becomes greater along with extension of the ATM switches in the exchange.
Abstract:
When broadcast is executed in an ATM mode, a subscriber is assigned a path and a channel as information by a central controller of a switching unit, and the information is added to a cell to be transmitted to the switching unit through a subscriber line. The switching unit comprises the central controller, a tag information adder, and a self-routing switch. The self-routing switch comprises a plurality of input lines and output lines, and unit switches provided for each input line corresponding to each of the output lines. The tag information adder adds routing information for the self-routing switch to a cell to be transmitted to the self-routing switching. The routing information comprises a set of bits corresponding to each output line, and the tag information adder adds to the cell the routing information in which a bit corresponding to an output line for transmitting the cell is set to a predetermined logical value. In executing the broadcast, a plurality of bits corresponding to a plurality of output lines are set to a predetermined logical value. The self-routing switch analyzes the routing information of the cell received by each unit switch, and outputs the cell to the outpost line if the bit corresponding to a unit switch is set to a predetermined logical value. If a plurality of bits of routing information are set to a predetermined value, the cell is outputted from a plurality of output lines, thus enabling the broadcast.
Abstract:
A switch interface unit, a monitor unit, and a control system interface unit are connected as external units to a highway to which a subscriber information processing unit is also connected so that a monitoring process, that is, a special study process, can be simplified and a cost charged for the subscriber information processing unit can be prevented from increasing greatly. Furthermore, in an accounting process, accounting parameters are accumulated in an accounting information accumulating unit for variations on compressed source addresses, not on source addresses. As a result, the accounting information accumulating unit, etc. can be realized with normal circuit elements only.
Abstract:
A first terminal unit is connected to a line switch via a set of data lines. A second terminal unit is connected to the first terminal unit via a set of data lines. A third terminal unit is connected to the second terminal unit via a set of data lines. Therefore, the terminals are sequentially connected in series. Cells transmitted to the terminals are multiplexed by each terminal and sequentially transmitted upstream, to the third terminal unit, the second terminal unit, and the first terminal unit together with a token. Since the first terminal unit receives a first identification signal from a switch and a second identification signal from downstream, the first terminal unit recognizes that it is the highest order terminal unit, and sends a cell to the switch after separating the cell from a token which is to be returned downstream. Since the second terminal unit does not receive the first identification signal and receives only the second identification signal, it recognizes that it is an intermediate terminal unit, and sends back downstream a token returned from upstream. Since the third terminal unit does not receive the identification signals, it recognizes that it is the lowest order terminal unit, and sends upstream a cell transmitted via a low data rate line according to a token returned from upstream.
Abstract:
A cell having an attribute of a point-to-multipoint connection is distributed to each of a number of subscribers using a point-to-multipoint connection distributing switch to be provided in parallel with a point-to-point connection, concentrating and distributing switch. Therefore, a hardware configuration can be simply established. Besides, both a point-to-point connection, and a point-to-multipoint connection can be made only by switching a cell to each switching unit, and a software configuration can thus be simplified.
Abstract:
On receiving voice data from a subscriber accommodated in a broadband network, a terminal adaptor separately puts the voice data in cells in 8-bit units every 125 .mu.s separately, and transmits the cells by a remote switching unit in the broadband network to subscriber terminal equipment. The subscriber terminal equipment accommodates and processes each item of 8-bit data in 24 channels in the PCM format, puts in cells the PCM-formatted data in 24 channels, and sends the cells sequentially to a broadband network transmission line through the remote switching unit. On receiving the above described data in cells, an adaptor provided between the broadband network and an existing telephone network converts the data to the PCM transmission format, and sends them to the existing telephone network after adding a signaling bit to them.