JP2009212724A - Switch device, and method and program for switching without instantaneous interruption thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make cell stored states and queue selected states of the switch parts of the current system and a preliminary system coincide with each other. <P>SOLUTION: A switch device includes: a cell counting part 101-10-1 for counting the number of stored cells in a buffer of the current system switch part; the number of stored cells notifying part 101-11-1 for storing the number of stored cells upon starting a switching sequence and notifying the number of stored cells from the current system to the preliminary system switch part; an arrival cell storing part 101-14-1 for storing cells that arrive at the preliminary system switch part from the beginning time sequentially; the number of stored cells analyzing part 101-18-1 for simulating queue selection of the current system switch part in a period of time shorter than a one-cell time until catching up with the present time; the number of cells adjusting part 101-19-1 for selecting a queue on the basis of the number of stored cells and simulated arrival cells and selecting queues for the number of stored cells; and a state control part 101-17-1 for instructing a buffer control part to start writing at the same time with a switching start and to start reading after adjusting the number of cells, and switches from the current system to the preliminary system switch part after outputting the same cell from the current system and the preliminary system switch part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a switch device that handles fixed length data. In particular, the present invention relates to a switch device for matching cell outputs of an active switch unit and a standby switch unit, an uninterruptible switching method, and a program.

  When there is a buffer for storing the input cells inside the active switch unit and the standby switch unit, a buffer selection method (Round Robin, Weighted Round Robin, complete priority, etc.) for matching the storage state and reading the cell is used. Since the cell outputs of the active system switch unit and the standby system switch unit cannot be matched unless the state (Round Robin pointer, etc.) is matched, the output unit simply selects from the active system switch unit to the standby system switch unit. Even if is switched, it cannot be switched without interruption.

Although not the active system switch unit and the standby system switch unit, as a method of synchronizing the switch elements in the switch that processes the bit sliced data by a plurality of switch elements (matching the number of stored data), for example, There is a method described in Patent Document 1.
An ATM switch is composed of a plurality of switch elements, and in order to provide a monitoring circuit for an ATM switch for monitoring and guaranteeing a synchronous operation between the elements, an input signal is multiplexed by a multiplexing unit and supplied to an address filter. The counter counts the number of cells stored in the buffer for each output port periodically, the counter count value is periodically stored in the register, the register stored value, and other switches The value of the register of the element is compared by a comparison circuit, the synchronization shift is monitored based on the comparison result, and a reset signal is transmitted when there is a mismatch, and synchronization control between the switch elements is performed (for example, Patent Document 1). reference).

  This is because the data storage number stored in all switch elements is transmitted to all other switch elements and the data storage number of all the switch elements is synchronized. If it does not match, it is determined that synchronization is not achieved, the buffer is reset, and the process is restarted to synchronize the switch elements.

In the case of this method, when it takes more than one cell time (for example, K cell time) to notify the number of accumulated data between switch elements, the standby system switch unit uses the active cell before K cell time. Since the number of accumulations and the state of the buffer selection method are notified, synchronization between switch elements cannot be achieved.
In addition, as a method of matching the cell outputs of the active switch unit and the standby switch unit, for example, there is a method described in Patent Document 2 below.

  In order to provide a redundant switching method that can perform redundant switching without interruption without causing cell delay even when a delay priority control function is provided, a switching control cell is generated for each delay priority class, and switching with the highest delay priority class is performed. In order from the control cell, the data is output to each queue provided in the active system switch unit and the standby system switch unit. In each queue of the active system switch, the switching control cell is accumulated and read out in the same manner as other cells, and The system switch unit initializes the queue in response to the arrival of the switching control cell, stops cell reading, and reads out the switching control cell from the active system switch, from the corresponding delay priority class queue in the standby system switching unit. Cell reading is resumed, and when the switching control cell of the lowest delay priority class is read from the active switch unit, it is read from the standby switch unit. And it selects output cell as the main signal (e.g., see Patent Document 2).

This is because when the buffer of the switch section is divided for each delay priority class, the buffer status of all priority classes is not adjusted to the status of all buffers at the same time, but from the buffer of the highest priority class in order. It is a method to go.
This method is applicable if it is a complete priority method (a method that always preferentially selects the highest priority buffer among the cells in which the cells are stored), but the buffer selection method is, for example, Round Robin or Weighted Round. This is not possible with the buffer selection method in which the buffers are sequentially selected as in the case of Robin.

Further, as a method of synchronizing the contents of the buffers in the active switch and the standby switch, for example, there is a method described in Patent Document 3 below.
In order to provide an ATM switch system that can be configured using only a circuit that is simple to implement, and that can switch redundantly without interruption, the contents of buffers in the active switch and the standby switch are synchronized. Therefore, each switch is provided with a circuit (T cell detection circuit and cell retention number detection circuit) for detecting the number of cells existing in the buffer when a cell having a predetermined content is input. The buffer of the standby switch is controlled according to the difference in the number of cells (synchronization of cells with a predetermined content), and when a cell with a predetermined content is detected in the subsequent stage of each switch In addition, the ATM switch system is configured so that the cells in the buffer of the standby switch are output to the outside (see, for example, Patent Document 3).

In order to synchronize, the active switch and the standby switch detect the number of cells existing in the buffer when a cell with a predetermined content is input, and respond to the difference in the number of cells. Thus, the buffer of the standby system switch is controlled.
As described above, this method can be applied to the complete priority method (always preferentially selecting the highest priority buffer among the buffers in which cells are stored), but the buffer selection method is, for example, Round. It is impossible to use a buffer selection method in which the buffers are selected in order as in the case of Robin and Weighted Round Robin.

Japanese Patent Laid-Open No. 08-242233 JP-A-10-190683 JP 08-139726 A

  Therefore, in view of the above problems, the present invention is not limited to the case where the process of notifying the standby switch unit of information such as the cell accumulation state and queue selection state in the active switch unit is completed in one cell time. Switch device that realizes uninterruptible switching by matching the cell storage state and queue selection state of the active system switch unit and the standby system switch unit for algorithms other than complete priority control as control, its uninterruptible switching method, And to provide a program.

  In order to solve the above problems, the present invention provides a distribution unit that distributes the same cell as fixed-length data to each of the active switch unit and the standby switch unit, and a buffer unit that stores the cells therein, A buffer control unit for controlling writing or reading of the buffer unit in accordance with a predetermined algorithm, and a selection unit for selecting one of the output cell from the active switch unit and the output cell from the standby switch unit In the switch device, the active switch unit is notified of a count value from the cell count unit that counts the number of cells stored in the buffer unit of the active switch unit, and the cell count unit, and a switching sequence start time Storing the number of storage cells in the storage system, and notifying the standby system switch unit from the active system switch unit, The standby switch unit includes an arrival cell storage unit that stores cells arriving at the standby switch unit in chronological order from a switching sequence start time, and a switching sequence start time notified from the active switch unit. Using the time-series cell arrival information stored in the arrival cell storage unit with the number of cells stored in the buffer unit as an initial state, the queue selection operation of the active switch unit is set to the current time in a time shorter than one cell time. Perform the queue selection operation based on the number of storage cells obtained as a result of the simulation from the storage cell analysis unit and the cells that arrive after the simulation, A cell number adjustment unit that operates until a queue is selected for the number of stored cells obtained as a result of the simulator, and a switching sequence. The buffer control unit is reset simultaneously with the start and simultaneously the write control and the read control are stopped. After the storage cell analysis in the storage cell number analysis unit is finished, the buffer control unit is instructed to start writing, and the cell number adjustment unit A state control unit for instructing the buffer control unit to start reading after the cell number adjustment is completed, and the cell storage state and the queue selection state in the buffer unit of the active system switch unit and the standby system switch unit match, A switching device that realizes uninterrupted switching by switching from the active switch unit to the backup switch unit in the selection unit after the same cell is always output from both I will provide a.

The buffer unit includes a plurality of queues.
In addition, a plurality of queues configured by the buffer unit are allocated for each priority class.
Further, synchronization of the start of the switching sequence between the active switch unit and the standby switch unit is performed in a common frame phase.
In addition, the switching control cell synchronizes the start of the switching sequence of the active switch unit and the standby switch unit.

Further, synchronization of the start of the switching sequence of the active switch unit and the standby switch unit is notified from one of the active switch unit and the standby switch unit to the other.
Further, the storage cell number notifying unit notifies the active switch unit to the standby switch unit together with the information on the number of stored cells at the switching sequence start time and the point information used for the queue selection operation.

In addition, the pointer used in the queue selection operation in both systems is set to the same predetermined value simultaneously with the start of the switching sequence from the active system switch unit to the standby system switch unit.
In addition, a buffer control / cell count unit for holding the number of storage cells in the standby system switch unit at the same time as the working system switch unit holds the number of storage cells is provided. Compare the number of cells with the number of stored cells received from the active switch unit, do nothing if they match, and perform a matching process if they are different, before switching processing in the selection unit A matching process is performed in advance.

  The present invention also provides an active switch unit having a buffer unit for storing fixed-length data as a cell and storing the cell therein, and a buffer control unit for controlling writing or reading of the buffer unit according to a predetermined algorithm, and A standby switch unit, a distribution unit that distributes the same cell to each of the active switch unit and the standby switch unit, an output cell from the active switch unit, and an output from the standby switch unit In a non-instantaneous switching method of a switching device including a selection unit that selects any one of cells, a step of counting the number of accumulated cells in the buffer unit of the active switch unit, and a count value is notified from the cell count unit The number of stored cells at the start time of the switching sequence is held, and the standby switch is connected from the active switch unit. A step of notifying the switch unit, a step of storing the cells arriving at the standby system switch unit in time series from the switching sequence start time, and the buffer unit at the time of starting the switching sequence notified from the active system switch unit Simulating the queue selection operation of the active switch unit using the time-series cell arrival information stored with the number of stored cells as an initial state until it catches up to the current time in a time shorter than one cell time; Queue selection operation based on the number of stored cells information obtained as a result of the above and the cells that arrive after simulation, and the process of switching until the number of stored cells obtained as a result of the simulator is selected. At the same time when the sequence starts, the buffer control unit is reset and at the same time the write control and read control are stopped and stored. The buffer control unit is instructed to start writing after the completion of cell analysis, the buffer control unit is instructed to start reading after the cell number adjustment is completed, and the cell storage in the buffer unit of the active system switch unit and the standby system switch unit After the state and the queue selection state match, and the same cell is always output from both, the switching unit switches from the active system switch unit to the standby system switch unit so that uninterruptible switching is performed. And a step of realizing the switching method.

The buffer unit includes a plurality of queues.
In addition, a plurality of queues configured by the buffer unit are allocated for each priority class.
Further, synchronization of the start of the switching sequence between the active switch unit and the standby switch unit is performed in a common frame phase.
In addition, the switching control cell synchronizes the start of the switching sequence of the active switch unit and the standby switch unit.

Further, synchronization of the start of the switching sequence of the active switch unit and the standby switch unit is notified from one of the active switch unit and the standby switch unit to the other.
Further, in addition to the information on the number of stored cells at the switching sequence start time, the point information used for the queue selection operation is also notified from the active switch unit to the standby switch unit.

In addition, the pointer used in the queue selection operation in both systems is set to the same predetermined value simultaneously with the start of the switching sequence from the active system switch unit to the standby system switch unit.
Further, at the same time when the working switch unit holds the number of storage cells, the number of storage cells of the standby switch unit is held, and the number of stored cells and the number of storage cells received from the working switch unit are The matching process is performed in advance before the switching process in the selection unit by performing no comparison if they match and performing the matching process if they are different.

  The present invention also provides an active switch unit having a buffer unit for storing fixed-length data as a cell and storing the cell therein, and a buffer control unit for controlling writing or reading of the buffer unit according to a predetermined algorithm, and A standby switch unit, a distribution unit that distributes the same cell to each of the active switch unit and the standby switch unit, an output cell from the active switch unit, and an output from the standby switch unit In a non-instantaneous switching program of a switching device including a selection unit for selecting any one of cells, a procedure for counting the number of accumulated cells in the buffer unit of the active switch unit, and a count value notified from the cell count unit The number of stored cells at the start time of the switching sequence is held, and the preliminary switch is sent from the active switch unit. A procedure for notifying the system switch unit, a procedure for storing cells arriving at the backup system switch unit in chronological order from the switching sequence start time, and the buffer unit at the start of the switching sequence notified from the active system switch unit. Using the time-series cell arrival information stored with the number of stored cells as an initial state, a procedure for simulating the queue selection operation of the active switch unit until it catches up to the current time in a time shorter than one cell time, Queue selection operation based on the number of stored cells information obtained as a result of the above and the cells that arrive after simulation, and the procedure to switch until the number of stored cells obtained as a result of the simulator is selected and switching At the same time when the sequence starts, the buffer control unit is reset and at the same time the write control and read control are stopped. A procedure for instructing the buffer control unit to start writing after the storage cell analysis is completed, and a command for instructing the buffer control unit to start reading after the adjustment of the number of cells, and a cell in the buffer unit of the active system switch unit and the standby system switch unit After the accumulation state and the queue selection state match, and the same cell is always output from both, the switching unit switches from the working system switch unit to the standby system switch unit so that the switch can be switched instantaneously. And a switch program for switching the switch device without interruption.

  As described above, according to the present invention, the number of storage cells in the buffer unit of the active system switch unit is counted, the count value is notified, the number of storage cells at the switching sequence start time is held, and the current system switch unit Notify the standby switch unit, store the cells arriving at the standby switch unit in chronological order from the switching sequence start time, and initialize the number of cells stored in the buffer unit at the start of the switching sequence notified from the active switch unit The number of stored cells obtained as a result of the simulation is simulated by using the time-series cell arrival information stored as, and simulating the queue selection operation of the active switch unit until it catches up to the current time in a time shorter than one cell time. Based on the information and the cells that arrive after simulation, a queue selection operation is performed and the result of the simulator is obtained. As many queues as the number of stored cells are selected, the buffer control unit is reset simultaneously with the start of the switching sequence, and simultaneously the write control and read control are stopped. After the storage cell analysis is completed, the buffer control unit starts writing. After the adjustment of the number of cells, the buffer control unit is instructed to start reading, and the cell storage state and queue selection state in the buffer unit of the active system switch unit and the standby system switch unit match, and the same cell is always output from both Since the switching unit is switched from the active system switch unit to the standby system switch unit by the selection unit to realize uninterruptible switching, the switching sequence start time in the standby system switch unit 101-22 is realized. Switch based on the number of cells stored in the active switch unit 101-4 and the time-series cell arrival information after the switching start time. Was to be able to reproduce the queue selection operation in sequence start time after the active system switch unit 101-4 instead.

  Conventionally, a switch unit having a buffer unit that stores therein fixed-length data (described as a cell) and a buffer control unit that controls writing or reading of the buffer unit according to a predetermined algorithm is referred to as an active switch unit. There are two standby switch units, one of the distribution (copy) unit that distributes the same cell to the active switch unit and the standby switch unit, the output cell from the active switch unit, and the output cell from the standby switch unit In a switch device including a selection unit for selecting one, when the switch unit selected by the selection unit is switched from the active system switch unit to the standby system switch unit, the cell storage state and the queue selection state of the active system switch unit (of Round Robin) If the pointers do not match, it will not be possible to switch to uninterrupted switching. In order to match the queue storage state with the queue selection state, the active switch unit notifies the standby switch unit of its own cell storage state and queue selection state, and the standby switch unit operates based on the information. However, if the notification process does not end in one cell time, the standby switch unit starts operation based on the status of the previous active switch unit. The cell accumulation state and the queue selection state of the switch unit and the standby system switch unit do not coincide with each other, so that the instantaneous switching without the selection unit cannot be realized.

  On the other hand, in the present invention, in the standby system switch unit, the number of cells stored in the active system switch unit at the switching sequence start time (including the Round Robin and Weighted Round Robin pointers and Weight information) and the switching start time and later Based on the time-series cell arrival information, the queue selection operation in the active switch unit after the switching sequence start time can be reproduced, so that the recognition of the number of stored cells in the active switch and the standby switch coincides. Because the operation of the active system switch and the standby system switch can be made to match completely, switching between the active system switch and the standby system switch can be realized by switching the switch to be selected by the selection unit of the output interface unit. It became so.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a switch device according to the present invention. As shown in this figure, the switch device 100 is used between N input interfaces 101-1-1 to 101-1-N and N output interfaces 101-20-1 to 101-20-N. It is a switch connected by the system switch unit 101-4 and the standby system switch unit 101-22, and performs the uninterruptible switching operation.

In this example, the number of input interfaces and the number of output interfaces are both N, which is the same number, but there is no problem even if the numbers are different.
The input interfaces 101-1-1 to 101-1-N fix received data in a block composed of the cell units 101-2-1 to 101-2-N and the distribution units 101-3-1 to 101-1-N. The data is divided into long data (cells), and the cells are distributed (copied) to the active system switch unit 101-4 and the standby system switch unit 101-22.

The active switch unit 101-4 is a block that performs switching processing of cells received from the input interfaces 101-1-1 to 101-1-N to the output interfaces 101-20-1 to 101-20-N as destinations. It comprises a multiplexing unit 101-5, filter units 101-1-6-1 to 101-6-N, and destination data management units 101-7-1 to 101-7-N.
Multiplexer 101-5 is a block that time-division-multiplexes cells input from input interfaces 101-1-1 to 101-1-N, and outputs multiplexed data to filter units 101-1-6-1 to 101-6-N. Is done.

The filter units 101-1-1 to 101-6 -N pass only cells from the destination a 1 (to the output interface 101-20-1) to the destination aN (to the output interface 101-20 -N) from the multiplexed data. Except for the block to be deleted, the processed data is sent to the destination data management units 101-7-1 to 101-7-N, respectively.
The destination data management unit 101-7-1 includes a buffer unit 101-8-1, a buffer control unit 101-9-1, a cell count unit 101-10-1, and an accumulated cell number notification unit 101-11.

The buffer unit 101-8-1 is a memory that is internally configured with a queue for each priority level, and is subjected to write control and read control from the buffer control unit 101-9-1, respectively.
The buffer control unit 101-9-1 divides the input cells for each priority and writes them to the buffer unit 101-8-1, and performs a queue selection process for reading the cells according to a predetermined algorithm. Read control is performed.

  Here, the “predetermined algorithm” is, for example, Round Robin for selecting a queue for sequentially reading cells of each priority one cell at a time. Reading is performed in order, but is determined for each priority, not for each cell. For example, a weighted round robin that selects a queue from which cells are read according to the ratio, a complete priority scheme that selects a queue in which cells with higher priority are stored, and the like can be considered.

The cell read from the buffer unit 101-8-1 is output to the destination output interface 101-20-1.
Further, the buffer control unit 101-9-1 sends the priority information of the cell written and read to the buffer unit 101-8-1 to the cell count unit 101-10-1.
The cell count unit 101-10-1 is a block that individually counts the number of accumulated cells stored in the buffer unit 101-8-1 for each priority based on the priority from the buffer control unit 101-9-1. The counted value is notified to the accumulated cell number notifying unit 101-11-1.

When the storage cell number notifying unit 101-11-1 is instructed to start the switching sequence from the switching start instructing unit 101-26 in the timing generating unit 101-25, the priority received from the cell counting unit 101-10-1 The number of cells counted individually is held and output to the standby system switch unit 101-22.
The operations of the destination data management units 101-7-2 to 101-7-N are different from each other only in handling the cells of the destinations a2 to aN, and the operations are the same as those of the destination data management unit 101-7-1.

  The standby switch unit 101-22 operates as a backup for the active switch unit 101-4, and the cells received from the input interfaces 101-1-1 to 101-1-N are output interfaces 101-20-1 to 101-2. 101-20-N is a block that performs switching processing, and includes a multiplexing unit 101-12, filter units 101-13-1 to 101-13-N, and destination data management units 101-23-1 to 101-23-N. .

Multiplexer 101-12 is a block for time-division multiplexing cells input from input interfaces 101-1-1 to 101-1-N, and multiplexed data is output to filter units 101-13-1 to 101-13-N. The
The filter units 101-13-1 to 101-13-N pass only the cells from the destination a1 (to the output interface 101-20-1) to the destination aN (to the output interface 101-20-N) from the multiplexed data. Except for the block to be deleted, the processed data is sent to the destination data management units 101-23-1 to 101-23-N, respectively.

The destination data management unit 101-23-1 includes an arrival cell storage unit 101-14-1, a buffer control unit 101-15-1, a buffer unit 101-16-1, a state control unit 101-17-1, and the number of stored cells. It comprises an analysis unit 101-18-1 and a cell number adjustment unit 101-19-1.
The buffer unit 101-16-1 is a memory that is internally configured with queues for each priority level, and is subjected to write control and read control from the buffer control unit 101-15-1.

The buffer control unit 101-15-1 divides the input cells for each priority and writes them to the buffer unit 101-16-1, performs a queue selection process for reading the cells according to a predetermined algorithm, and reads the cells. Take control.
In addition, the buffer control unit 101-15-1 resets the buffer unit 101-16-1 (clears and empties the buffer unit) in accordance with an instruction from the state control unit 101-17-1, stops / starts cell writing, Each cell read / stop state is defined.

The cell read from the buffer unit 101-8-1 is output to the destination output interface 101-20-1.
In addition, when the arrival cell storage unit 101-14-1 is instructed to start the switching sequence from the switching start instruction unit 101-26 in the timing generation unit 101-25, the arrival cell storage unit 101-14-1 sets the priority of the cell arriving at itself from that time. The block is stored in the series, and the stored time-series cell priority information is notified to the accumulated cell number analyzing unit 101-18-1 in accordance with a request from the accumulated cell number analyzing unit 101-18-1.

  The accumulated cell number analysis unit 101-18-1 stores the accumulated cell number information and the arrival cell storage for each priority at the start of the switching sequence received from the accumulated cell number notification unit 101-11-1 in the active switch unit 101-4. Based on the time-series cell priority information received from the unit 101-14-1, the queue selection operation of each priority of the buffer control unit 101-9-1 of the active switch unit from the start of the switching sequence is analyzed. The information on the number of stored cells for each priority after simulation in the (simulated) block is output to the cell number adjusting unit 101-19-1, and the operation state (under analysis or under analysis) is output to the state control unit 101- Notify 17-1.

  The cell number adjustment unit 101-19-1 is based on the number of stored cells for each priority after simulation received from the stored cell number analysis unit 101-18-1 and the priority information of the received cells. The queue selection process is simulated on the assumption that the number of cells is within −16-1, and the priority information that the queues are selected by the number of stored cells received from the stored cell number analysis unit 101-18-1 ( Hereinafter, the state control unit 101-17-1 is notified of the adjustment completion notification.

  The state control unit 101-17-1 is a block for controlling the operation state of the buffer control unit 101-15-1, and receives a switching sequence start instruction from the switching start instruction unit 101-26 in the timing generation unit 101-25. Requests for buffer reset, cell write stop and read stop are sent to the buffer unit 101-16-1, and when the status of the operation notified from the accumulated cell number analysis unit 101-18-1 becomes non-analyzed, all priority is given. Cell buffer start instruction is sent to the buffer control unit 101-15-1, and when an adjustment end notification is received from the cell number adjustment unit 101-19-1, a cell read instruction with the corresponding priority is sent to the buffer control unit 101-15. -1.

  The output interfaces 101-20-1 to 101-20-N are blocks that receive the cells after the switching process from the active switch unit 101-4 and the standby switch unit 101-22. 1 to 101-21-N. The selection units 101-21-1 to 101-21-N select one of the cells received from the active system switch unit 101-4 and the standby system switch unit 101-22 and select the decellization unit 101-. This block is output to 24-1 to 101-24-N.

  The selection units 101-21-1 to 101-21-N monitor cells received from the active switch unit 101-4 and the standby switch unit 101-22 and receive from the active switch unit 101-4. If the cell and the cell received from the standby system switch unit 101-22 are monitored to synchronize, and switching is performed from the active system switch unit 101-4 to the standby system switch unit 101-22 Non-instantaneous switching can be realized.

The cells selected by the selection units 101-21-1 to 101-21-N are converted into TDM (Time Division Multiplex) data, ATM (Asynchronous Transfer Mode) by the decelerating units 101-24-1 to 101-24-N. ) It is converted into the accommodated interface format such as a cell or a variable length packet.
The timing generation unit 101-25 is a block for sending a switching sequence start instruction signal for synchronizing the switching sequence start with a common frame to the active switch unit 101-4 and the standby switch unit 101-22. 101-26.

The switching start instructing unit 101-26 sends a timing signal (switching sequence start instructing signal) as a starting point for starting the switching sequence.
Next, the operation of this embodiment shown in FIG. 1 will be described.
First, the data switching operation in this embodiment shown in FIG. 1 will be described. The input interfaces 101-1-1 to 101-1-N accommodate TDM data, ATM cells, variable-length packets, and the like, and these data are stored in the cell units 101-2-1 to 101-2-N. The data is divided into fixed length data (cells) which are switching units within.

The cells are distributed to the active switch unit 101-4 and the standby switch unit 101-22 in the distribution units 101-3-1 to 101-3-N.
The cells that have arrived at the active switch unit 101-4 from the input interfaces 101-1-1 to 101-1-N are subjected to time division multiplexing processing by the multiplexing unit 101-5, and the filtering units 101-1-6-1 to 101-6. -N

The filter units 101-1-1 to 101-6 -N pass only the cells from the destination a 1 (to the output interface 101-20-1) to the destination aN (to the output interface 101-20 -N) from the multiplexed data. Are deleted and transmitted to the subsequent destination data management units 101-7-1 to 101-7-N.
The cell received by the destination data management unit 101-7-1 is stored in the queue of the corresponding priority of the buffer unit 101-8-1 under the control of the buffer control unit 101-9-1.

The buffer control unit 101-9-1 performs a queue selection process for reading a cell from the buffer unit 101-8-1, and performs a cell read process for the selected queue.
The read cell is output to the output interface 101-20-1.
The operations of the destination data management units 101-7-1 to 101-7-N are the same as those of the destination data management unit 101-7-1, except that the cells of the destinations a2 to aN are different.

  Regarding normal switching operations in the multiplexing unit 101-12, the filter units 101-13-1 to 101-13-N, and the destination data management units 101-23-1 to 101-23-N of the standby switch unit 101-22 Are the same as the operations of the multiplexing unit 101-5, the filter units 101-1-6-1 to 101-6-N, and the destination data management units 101-7-1 to 101-7-N of the active switch unit 101-4. It is.

  The output interfaces 101-20-1 to 101-20-N receive the cells after the switching processing from the active system switch unit 101-4 and the standby system switch unit 101-22, and select the units 101-21-1 to 101-. At 21-N, one of the cells received from the active switch unit 101-4 and the standby switch unit 101-22 is selected, and the cells are changed to the decelling units 101-24-1 to 101-24-N. Output.

In the decelerating units 101-24-1 to 101-24-N, the received cells are converted into accommodated interface formats such as TDM data, ATM cells, and variable-length packets.
Next, a switching sequence from the active switch unit 101-4 to the standby switch unit 101-22 in this embodiment will be described below. In this description, the destination data management unit 101-7-1 and the destination data management unit 101-23-1 that handle cells destined for the output interface 101-20-1 will be described, but the destination data management unit 101-7-2 to 101-7-N and the destination data management unit 101-23-3-2 to 101-23-N are the same in the process except that the cell destination is different.

  The start timing of the switching sequence is notified from the switching start instruction unit 101-26 in the timing generation unit 101-25 to the active switch unit 101-4 and the standby switch unit 101-22.

In the active switch unit 101-4, the cell count unit 101-10-1 counts the number of accumulated cells in the buffer unit 101-8-1 for each priority.
When the storage cell number notifying unit 101-11-1 is notified of the start of the switching sequence from the switching start instructing unit 101-26, the number of stored cells for each priority received from the cell counting unit 101-10-1 is displayed. The stored cell number analysis unit 101-18-1 in the standby system switch unit 101-22 is notified.

In the standby switch unit 101-22, the arrival cell storage unit 101-14-1 in the destination data management unit 101-23-1 arrives when the start of the switching sequence is notified from the switching start instruction unit 101-26. The process of storing the priorities of chronologically is started.
When the state control unit 101-17-1 is notified of the start of the switching sequence from the switching start instruction unit 101-26, the buffer control unit 101-15-1 is reset to the buffer unit 101-16-1. (Clear) and stop writing / reading are instructed.

  In the storage cell number analysis unit 101-18-1, the number of storage cells for each priority stored in the buffer unit 101-8-1 from the storage cell number notification unit 101-11-1 in the active switch unit 101-4. Is received, the arrival cell storage unit 101-14-1 is made to output the stored time-series cell priority information to the accumulated cell number analysis unit 101-18-1.

In the accumulated cell number analyzing unit 101-18-1, the buffer control unit of the active switch unit 101-4 from the start of the switching sequence based on the time-series cell priority information and the accumulated cell number for each priority. The queue selection operation of each priority of 101-9-1 is analyzed (simulated).
The queue selection operation to be simulated can catch up to the queue selection processing in the buffer control unit 101-9-1 at the current time by performing processing for one cell in a time shorter than one cell time. The number of stored cells for each priority in the buffer unit 101-8-1 in the system switch unit 101-4 can be known by the stored cell number analyzing unit 101-18-1.

The number of stored cells for each priority at the current time obtained as a result of the simulation is output to the cell number adjusting unit 101-19-1.
Further, the operation state (analyzing or not analyzing) is output from the accumulated cell number analyzing unit 101-18-1 to the state control unit 101-17-1, and the state control unit 101-17-1 When a change from analysis to non-analysis is detected, the buffer control unit 101-15-1 is instructed to start writing of cells of all priorities.

  The cell number adjustment unit 101-19-1 is based on the number of stored cells for each priority after simulation received from the stored cell number analysis unit 101-18-1 and the priority information of the received cells. The queue selection process is simulated on the assumption that the number of cells is within −16-1, and the priority information that the queues are selected by the number of stored cells received from the stored cell number analysis unit 101-18-1 ( Hereinafter, the state control unit 101-17-1 is notified of the adjustment completion notification.

When the state control unit 101-17-1 receives the adjustment end notification from the cell number adjustment unit 101-19-1, the cell control unit 101-15-1 is notified of a cell read instruction with a corresponding priority.
When this process is performed for all priorities, the number of storage cells of all priorities in the buffer unit 101-8-1 in the active switch unit 101-4 and the buffer unit 101-16-1 in the standby switch unit 101-22. Therefore, the operation of the active switch unit 101-4 and the standby switch unit 101-22 can be completely matched.

  The selection unit 101-21-1 in the output interface 101-20-1 monitors the cells received from the active system switch unit 101-4 and the standby system switch unit 101-22, and receives the cells from the active system switch unit 101-4. If the cell and the cell received from the standby system switch unit 101-22 are monitored to synchronize, and switching is performed from the active system switch unit 101-4 to the standby system switch unit 101-22 Non-instantaneous switching can be realized.

  Further, in the buffer control unit 101-9-1 and the buffer control unit 101-15-1 in FIG. 1, when the queue selection processing is performed by the round robin or weighted round robin control, the pointer information and the weight information. Is necessary for the queue selection processing, but the active switch unit 101-4 notifies the standby switch unit 101-22 together with the pointer information and the weight information together with the stored cell number information, thereby analyzing the stored cell number. The active-use queue selection process can be reproduced by the simulation process in the unit 101-18-1 and the cell number adjustment unit 101-19-1.

  Further, even if the pointer information and the weight information are not sent from the active switch unit 101-4 to the standby switch unit 101-22, the pointer information and the weight are reset at the same time as the switching sequence start timing, so that the active switch The pointer information and the weight can be recognized together in the queue selection processing from the unit 101-4 to the standby system switch unit 101-22.

FIG. 2 shows a series of processes for matching the number of stored cells in the buffer unit 101-8-1 of the active system switch unit 101-4 and the buffer unit 101-16-1 of the standby system switch unit 101-22 in FIG. It is a figure explaining to a time series.
Next, the operation of this embodiment shown in FIG. The numbers of the blocks in this figure correspond to those in FIG.

As shown in the figure, at the switching sequence start time (T1), the storage cell number notifying unit 101-11-1 in the working switch unit 101-4 reserves the number of cells stored in the buffer in the working switch unit 101-4. This is notified to the storage cell number analysis unit 101-18-1 in the system switch unit 101-22 (see (1) in the figure).
At the switching start time (T1), the state control unit 101-17-1 starts the process of storing the priorities of the cells arriving in the arrival cell storage unit 101-14-1 in time series, and at the same time, the buffer control unit 101-15-1 is instructed to reset (clear) the buffer unit 101-16-1, stop writing, and stop reading.

The notification of the time series information of the arrival cell is started from the arrival cell storage unit 101-14-1 to the accumulated cell number analysis unit 101-18-1 (see (2) in the figure). When the accumulated cell number information arrives (time T2), the accumulated cell number analysis unit 101-18-1 starts from time T1 based on the accumulated cell number information and the arrival cell information from the arrival cell storage unit 101-14-1. The queue selection operation of the active switch unit 101-4 is simulated.
When the simulation operation in the storage cell number analysis unit 101-18-1 catches up with the queue selection operation of the current system switch unit 101-4 at the current time (T3), the number of storage cells in the current system switch unit 101-4 This means that the recognition of the number of cells in the storage cell number analysis unit 101-18-1 in the standby system switch unit 101-22 coincides.

At the timing (T3) when the simulation process in the storage cell number analysis unit 101-18-1 is completed (T3), the number of storage cells for each priority for which the simulation result is obtained from the storage cell number analysis unit 101-18-1. Is output to the cell number adjustment unit 101-19-1, the operation state is notified to the state control unit 101-17-1 (see (3) in the figure), and the state control unit 101-17-1 performs buffer control. The unit 101-15-1 is instructed to write cells at all priorities.
Further, at T3, the cell number adjustment unit 101-19-1 performs buffering based on the number of accumulated cells for each priority after simulation in the accumulated cell number analysis unit 101-18-1 and the cells arriving after T3. The queue selection operation in the control unit 101-15-1 is simulated, and the state control is sequentially performed from the priority selected for the number of storage cells after simulation obtained from the storage cell number analysis unit 101-18-1. The state control unit 101-17-1 instructs the buffer control unit 101-15-1 to start reading from the notified priority.

When the read instruction is completed for all priorities (T4), the operations of the destination data management unit 101-7-1 and the destination data management unit 101-23-1 match.
FIG. 3 shows a series of processing steps for matching the numbers of stored cells in the buffer unit 101-8-1 of the active system switch unit 101-4 and the buffer unit 101-16-1 of the standby system switch unit 101-22 in FIG. FIG. T1, T2, T3, and T4 shown in this figure are the same as T1, T2, T3, and T4 in FIG. 2, and the numbers described in the squares in the figure indicate the priority of the cell.

As shown in this figure, the buffer of the active system switch unit 101-4 and the buffer of the standby system switch unit 101-22 assign priority to cells destined for a specific destination (for example, the output interface 101-20-1 in FIG. 1). It is assumed that there are two priority classes. Hereinafter, (1) to (6) will be described.
(1) shows the state at time T1, and the number of stored cells from the active switch unit 101-4 to the standby switch unit 101-22 (priority 1 is 3 cells ... priority K is 4 cells). ) Is output.

The standby switch unit 101-22 starts chronological storage of the arriving cells for each priority (the cells arriving at the standby switch unit 101-22 are the cells arriving at the active switch unit 101-4). The same).
In addition, the standby switch unit 101-22 clears the buffer unit 101-16-1 and stops cell writing and reading.

(2) shows the operation from time T1 + 1 to time T2-1 (in this example, 3 cell times).
The active switch unit 101-4 operates as usual, and the standby switch unit 101-22 stores the arriving cells in chronological order for each priority, continuing from (1).
(3) shows the operation from time T2 to T3-1 (in this example, 4 cell time).

At the time T2, the information on the number of cells stored in the active switch unit 101-4 at the time T1 output from the active switch at (1) is received by the standby switch unit 101-22.
The standby switch 101-22 simulates the queue selection operation in the active switch unit 101-4 from time T1 based on the cell accumulation information and the arrival cell information stored from time T1, and at time T3. The active switch unit 101-4 recognizes that three cells of priority 1 are stored and four cells of priority 2 are stored.

(4) shows the buffer accumulation state of the active switch unit 101-4 and the standby switch unit 101-22 at time T3.
(5) shows the operation from time T3 to time T4-1 (7 cell time in this example).
From time T3, the standby switch unit 101-22 also starts the process of writing the received cell to the buffer unit 101-16-1.

In addition, the standby switch unit 101-22 selects the queue based on the simulation result obtained in (3) (priority 1 stores 3 cells and priority 2 stores 4 cells) and cells arriving after T3. Simulate the behavior.
(6) shows the operation after time T4.
After time T3, when the corresponding queues are selected corresponding to the simulation result obtained in (3), the queue reading process for that priority is started, and queue reading for all priorities is started at time T4. Thus, the operations of the active switch unit 101-4 and the standby switch unit 101-22 completely match.

In this way, in the standby switch unit 101-22, the switching sequence start time based on the number of cells stored in the active switch unit 101-4 at the switching sequence start time and the time-series cell arrival information after the switching start time. The queue selection operation in the subsequent active switch unit 101-4 can be reproduced.
Conventionally, a switch unit having a buffer unit that stores therein fixed-length data (described as a cell) and a buffer control unit that controls writing or reading of the buffer unit according to a predetermined algorithm is referred to as an active switch unit. There are two standby switch units, one of the distribution (copy) unit that distributes the same cell to the active switch unit and the standby switch unit, the output cell from the active switch unit, and the output cell from the standby switch unit In a switch device including a selection unit for selecting one, when the switch unit selected by the selection unit is switched from the active system switch unit to the standby system switch unit, the cell storage state and the queue selection state of the active system switch unit (of Round Robin) If the pointers do not match, it will not be possible to switch to uninterrupted switching. In order to make the accumulation state and the queue selection state coincide with each other, the active system switch unit notifies the standby system switch unit of its own cell storage state and queue selection state, and the standby system switch unit operates based on the information. However, if the notification process does not end in one cell time, the standby system switch unit will start operation based on the previous status of the active system switch unit. The cell accumulation state and the queue selection state of the switch unit and the standby system switch unit do not match, and the instantaneous switching without the selection unit cannot be realized.

  On the other hand, in the present invention, in the standby system switch unit, the number of cells stored in the active system switch unit at the switching sequence start time (including the Round Robin and Weighted Round Robin pointers and Weight information) and the switching start time and later Based on the time-series cell arrival information, the queue selection operation in the active switch unit after the switching sequence start time can be reproduced, so that the recognition of the number of stored cells in the active switch and the standby switch coincides. Because the operation of the active system switch and the standby system switch can be made to match completely, switching between the active system switch and the standby system switch can be realized by switching the switch to be selected by the selection unit of the output interface unit. It became so.

FIG. 4 is a block diagram showing a schematic partial configuration of a switch device according to the present invention, which is a first modification of FIG. As shown in the figure, compared with FIG. 1, blocks that have no difference in configuration blocks in the active switch unit 101-4 and the standby switch unit 101-22 are omitted.
In FIG. 1, the switching sequence start instruction signal is distributed from the switching start instruction unit 101-26 to the active switch unit 101-4 and the standby switch unit 101-22, but instead of the switching start instruction unit 101-26, In FIG. 4, the switching sequence start instruction to the active switch unit 101-4 and the standby switch unit 101-22 is recognized by the switching cell inserted from the input interface units 101-1-1 to 101-1-N.

In FIG. 4, the start of the switching sequence starts with the active switch at the switching cell inserted from the switching cell insertion unit 104-1-1 to 104-1-N in the input interface unit 101-1-1 to 101-1-N. Is notified to the unit 101-4 and the standby system switch unit 101-22.
A switching cell may be realized by defining a switching start bit in the header portion of a cell in which a main signal (packet, ATM cell, TDM data, etc.) is cellized, or a switching cell start notification dedicated cell is defined. May be.

In the active system switch unit 101-4 and the standby system switch unit 101-22, the switching cell detection units 104-2-1 to 104-2-N and the switching cell detection unit are placed after the multiplexing unit 101-5 and the multiplexing unit 101-12. 104-3-1 to 104-3-N are provided, and the switching cell detection units 104-2-1 to 104-2-N and the switching cell detection units 104-3-1 to 104-4-N receive cells. The switching sequence start instruction signal is detected from, the switching sequence start timing is recognized, and the switching process is started.
The operation after the start of the switching sequence is the same as in the embodiment of FIG.

FIG. 5 is a block diagram showing a schematic partial configuration of a switch device according to the present invention, which is a second modification of FIG. 1, and FIG. 6 is a third modification of FIG. 1, and a switch according to the present invention. It is a block diagram which shows the schematic partial structure of an apparatus.
As shown in FIG. 5, compared with FIG. 4, in FIG. 4, the switching cell is detected by both the active system switch unit 101-4 and the standby system switch unit 101-22, but the multiplexing unit 101-5 The switching cell detection units 104-2-1 to 104-2-N are provided later, and the switching cell detection units 104-2-1 to 104-2-N detect the switching cells only in the active switch unit 101-4. The detected timing is notified to the standby system switch unit 101-22.

  In FIG. 6, compared to FIG. 5, the switching cell detection units 104-3-104 to 104-3 N are provided after the multiplexing unit 101-12, and the switching cell detection units 104-3-1 to 104-3 are provided. With -N, the switch cell is detected only by the standby system switch unit 101-22, and the detected timing is notified to the active system switch unit 101-4. The operation after the start of the switching sequence is the same as that in the embodiment of FIG.

  FIG. 7 is a block diagram showing a schematic partial configuration of a switch device according to the present invention, which is a third modification of FIG. 1, and FIG. 8 is a fourth modification of FIG. 1, and is a switch according to the present invention. It is a block diagram which shows the schematic partial structure of an apparatus. As shown in FIG. 7, compared with FIG. 1, in FIG. 1, the switching sequence start instruction signal is distributed from the switching start instruction unit 101-26 to the active switch unit 101-4 and the standby switch unit 101-22. However, switching timing detectors 107-1-1 to 107-1-N are provided in the working system switch unit 101-4, and a switching start instruction is issued by the switching timing detectors 107-1-1 to 107-1-N. The switching sequence start instruction signal from the unit 101-26 is detected only by the active switch unit 101-4, and the detected timing is notified to the standby switch unit 101-22.

  In FIG. 8, switching timing detection units 108-1-1 to 108-1 -N are provided in the standby system switch unit 101-22, and switching is started by the switching timing detection units 108-1-1 to 108-1 -N. The switching sequence start instruction signal from the instruction unit 101-26 is detected only by the standby system switch unit 101-22, and the detected timing is notified to the active system switch unit 101-4. The operation after the start of the switching sequence is the same as in the embodiment of FIG.

  FIG. 9 is a block diagram showing a schematic partial configuration of a switch device according to the present invention, which is a fifth modification of FIG. As shown in this figure, in comparison with FIG. 1, instead of the buffer control unit 101-15-1 in the standby system switch unit 101-22 destination data management unit 101-23-1, a buffer control / cell count unit 109- 1-1, and the buffer control unit / cell count unit 109-1-1 starts the switching sequence from the switching start instruction unit 101-26 in addition to the function of the buffer control unit 101-15-1 in FIG. Is received, the number of stored cells in the buffer unit 101-16-1 at that time is held, and the stored number of stored cells and the stored cells in the buffer unit 101-8-1 sent from the active switch unit 101-4 The number is compared, and if they match, the writing / reading process of the buffer unit 101-16-1 is continued without executing the switching sequence.

  As a result, the number of stored cells in the buffer unit 101-8-1 in the active system switch unit 101-4 and the buffer unit 101-16-1 in the standby system switch unit 101-22 have already been changed before the switching sequence is started. If they match, it is possible to avoid performing the cell number matching process anew, and to perform the cell matching process only when the number of stored cells is different.

It is a block diagram which shows schematic structure of the switch apparatus which concerns on this invention. A series of processes for matching the number of accumulated cells in the buffer unit 101-8-1 of the active system switch unit 101-4 and the buffer unit 101-16-1 of the standby system switch unit 101-22 in FIG. It is a figure explaining. A series of processing steps for matching the numbers of stored cells in the buffer unit 101-8-1 of the active system switch unit 101-4 and the buffer unit 101-16-1 of the standby system switch unit 101-22 in FIG. FIG. FIG. 8 is a block diagram showing a schematic partial configuration of the switch device according to the invention, which is a first modification of FIG. 1. FIG. 9 is a block diagram showing a schematic partial configuration of the switch device according to the invention, which is a second modification of FIG. 1. FIG. 8 is a block diagram showing a schematic partial configuration of a switch device according to the invention, which is a third modification of FIG. 1. FIG. 8 is a block diagram showing a schematic partial configuration of a switch device according to the invention, which is a third modification of FIG. 1. FIG. 10 is a block diagram showing a schematic partial configuration of the switch device according to the invention, which is a fourth modification of FIG. 1. FIG. 9 is a block diagram showing a schematic partial configuration of a switch device according to the present invention, which is a fifth modification of FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Switch apparatus 101-1-1 to 101-1-N ... Input interface 101-2-1 to 101-2-N ... Cell-ized part 101-3-1 to 101-3-N ... Distribution part 101-4 ... active system switch unit 101-5 ... multiplexing units 101-6-1 to 101-6-N ... filter units 101-7-1 to 101-7-N ... destination data management units 101-8-1 to 101-8 -N ... Buffer unit 101-9-1 ... Buffer control unit 101-10-1 ... Cell count unit 101-11-1 ... Accumulated cell number notification unit 101-12 ... Multiplexing unit 101-13-1 ... Filter unit 101- 14-1 ... Arrival cell storage unit 101-15-1 ... Buffer control unit 101-16-1 ... Buffer unit 101-17-1 ... State control unit 101-18-1 ... Accumulated cell number analysis unit 101-19-1 ... Cell number adjustment unit 101-20 1~101-20-N ... output interface 101-21-1~101-21-N ... selector 101-22 ... standby system switch unit 101-23-1~101-23-N ... destination data management unit
101-24-1 to 101-24-N ... Decelization unit 101-25 ... Timing generation unit 101-26 ... Switch start instruction units 104-1-1 to 104-1-N ... Switch cell insertion unit 104-2- 1-104-2-N ... switching cell detectors 104-3-10-104-3 -N ... switching cell detectors 107-1-1 to 107-1 -N ... switching timing detectors 108-1-1 108-1-N: switching timing detection unit 109-1-1 ... buffer control / cell count unit

Claims (19)

In each of the active switch unit and the standby switch unit, a distribution unit that distributes the same cell as fixed-length data as a cell, a buffer unit that stores the cell therein, and a write to the buffer unit according to a predetermined algorithm Alternatively, in a switch device including a buffer control unit that performs read control, and a selection unit that selects any one of the output cell from the active switch unit and the output cell from the standby switch unit,
In the working system switch part,
A cell count unit that counts the number of accumulated cells in the buffer unit of the active switch unit;
The count value is notified from the cell count unit, the number of storage cells at the switching sequence start time is held, and the storage cell number notification unit for notifying from the active switch unit to the standby switch unit,
In the spare system switch part,
An arrival cell storage unit for storing cells arriving at the standby switch unit in time series from a switching sequence start time;
Using the time-series cell arrival information stored in the arrival cell storage unit as an initial state, the number of cells stored in the buffer unit at the start of the switching sequence notified from the active switch unit is used. An accumulated cell number analysis unit that simulates a queue selection operation in less than one cell time until it catches up with the current time;
The queue selection operation is performed based on the information on the number of stored cells obtained as a result of simulation from the storage cell analysis unit and the cells arriving after the simulation, and only the number of queues obtained as a result of the simulator is selected. A cell number adjustment unit that operates until
The buffer control unit is reset simultaneously with the start of the switching sequence, and at the same time, the write control and the read control are stopped. After the storage cell analysis in the storage cell number analysis unit is completed, the buffer control unit is instructed to start writing, and the number of cells A state control unit that instructs the buffer control unit to start reading after the adjustment of the number of cells in the adjustment unit,
After the cell storage state and the queue selection state in the buffer unit of the working system switch unit and the standby system switch unit match and the same cell is always output from both, the working unit performs the working A switching device characterized in that non-instantaneous switching is realized by switching from a system switch unit to the backup system switch unit. The switch device according to claim 1, wherein the buffer unit includes a plurality of queues. The switch device according to claim 2, wherein a plurality of queues configured by the buffer unit are allocated for each priority class. 4. The switch device according to claim 1, wherein synchronization of start of a switching sequence of the active system switch unit and the standby system switch unit is performed in a common frame phase. 5. 4. The switch device according to claim 1, wherein synchronization of start of a switching sequence of the active system switch unit and the standby system switch unit is performed in a switching control cell. 5. 6. The synchronization of the start of the switching sequence of the active system switch unit and the standby system switch unit is notified from one of the active system switch unit and the standby system switch unit to the other. The switch device according to 1. The accumulated cell number notifying unit notifies the standby switch unit from the active switch unit together with the information on the number of accumulated cells at the switching sequence start time and the point information used for the queue selection operation. The switch device according to any one of claims 1 to 6. The pointers used in the queue selection operations in both systems are set to the same predetermined value simultaneously with the start of the switching sequence from the active system switch unit to the standby system switch unit. The switch device according to claim 6. A buffer control / cell count unit for holding the number of storage cells of the standby system switch unit at the same time as the active system switch unit holds the number of storage cells, and the buffer control / cell count unit holds the number of stored cells Is compared with the number of stored cells received from the active switch unit, and if they match, nothing is performed, and if they are different, a matching process is performed, so that the matching is performed in advance before the switching process in the selection unit. The switch device according to any one of claims 1 to 8, wherein an insertion process is performed. A working switch unit and a standby switch unit each having a buffer unit for storing fixed-length data as a cell and storing the cell therein, and a buffer control unit for controlling writing or reading of the buffer unit according to a predetermined algorithm are provided. Further, a distribution unit that distributes the same cell to each of the active system switch unit and the standby system switch unit, an output cell from the active system switch unit, and an output cell from the standby system switch unit In the non-instantaneous switching method of the switch device including the selection unit to select,
Counting the number of accumulated cells in the buffer unit of the active switch unit;
A step of notifying the count value, holding the number of storage cells at the switching sequence start time, and notifying the standby switch unit from the active switch unit;
Storing cells arriving at the standby switch unit in chronological order from the switching sequence start time;
Using the time-series cell arrival information stored as the initial state, the number of cells stored in the buffer unit at the start of the switching sequence notified from the active switch unit, the queue selection operation of the active switch unit is performed for one cell. A process of simulating to catch up with the current time in a time shorter than the time,
A queue selection operation based on the information on the number of stored cells obtained as a result of the simulation and the cells arriving after the simulation, and a step of operating until queues are selected by the number of stored cells obtained as a result of the simulator; ,
At the same time as the switching sequence is started, the buffer control unit is reset and at the same time, the write control and the read control are stopped. After the storage cell analysis is completed, the buffer control unit is instructed to start writing. A step of instructing,
After the cell storage state and the queue selection state in the buffer unit of the working system switch unit and the standby system switch unit match and the same cell is always output from both, the working unit performs the working And a step of realizing uninterruptible switching by switching from the system switch unit to the backup system switch unit. The method according to claim 10, wherein the buffer unit includes a plurality of queues. The switching method of the switching apparatus of Claim 10 characterized by the above-mentioned. The several queue comprised by the said buffer part is allocated for every priority class. The switch device according to any one of claims 10 to 12, wherein synchronization of switching sequence start of the active system switch unit and the standby system switch unit is performed in a common frame phase. Non-instantaneous switching method. The switching device according to any one of claims 10 to 12, wherein synchronization of switching sequence start of the active system switch unit and the standby system switch unit is performed in a switching control cell. Non-instantaneous switching method. 15. The synchronization of the start of the switching sequence of the active system switch unit and the standby system switch unit is notified from one of the active system switch unit and the standby system switch unit to the other. A switching method for the switch device described in the above. The point information used for the queue selection operation in addition to the information on the number of stored cells at the switching sequence start time is also notified from the active switch unit to the standby switch unit. The method for switching the switch device without interruption in any one of claims 15. 11. The pointer used in the queue selection operation in both systems is set to the same predetermined value simultaneously with the start of the switching sequence from the active system switch unit to the standby system switch unit. The method for switching the switch device without interruption in any one of claims 15. At the same time that the working system switch unit holds the number of storage cells, the number of storage cells in the standby system switch unit is held, and the number of stored cells is compared with the number of storage cells received from the working system switch unit The process is performed in advance before the switching process in the selection unit by performing nothing and performing nothing if they match and performing a matching process if they are different. A method for switching the switch device without any interruption according to any one of claims 10 to 17. A working switch unit and a standby switch unit each having a buffer unit for storing fixed-length data as a cell and storing the cell therein, and a buffer control unit for controlling writing or reading of the buffer unit according to a predetermined algorithm are provided. Further, a distribution unit that distributes the same cell to each of the active system switch unit and the standby system switch unit, an output cell from the active system switch unit, and an output cell from the standby system switch unit In the non-instantaneous switching program of the switch device including the selection unit to select,
A procedure for counting the number of cells stored in the buffer unit of the active switch unit;
A procedure for notifying the count value, holding the number of storage cells at the switching sequence start time, and notifying the standby switch unit from the active switch unit,
A procedure for storing cells arriving at the standby switch unit in chronological order from the switching sequence start time;
Using the time-series cell arrival information stored as the initial state, the number of cells stored in the buffer unit at the start of the switching sequence notified from the active switch unit, the queue selection operation of the active switch unit is performed for one cell. A procedure to simulate until it catches up with the current time in less time,
A procedure for performing a queue selection operation based on the information on the number of stored cells obtained as a result of simulation and cells arriving after the simulation, and operating until queues are selected for the number of stored cells obtained as a result of the simulator; ,
At the same time as the switching sequence is started, the buffer control unit is reset and at the same time, the write control and the read control are stopped. After the storage cell analysis is completed, the buffer control unit is instructed to start writing. With instructions to
After the cell storage state and the queue selection state in the buffer unit of the working system switch unit and the standby system switch unit match and the same cell is always output from both, the working unit performs the working And a procedure for realizing uninterruptible switching by switching from the system switch unit to the backup system switch unit.

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