JP5551958B2 - Data transfer system and data transfer method - Google Patents

Description

  The present invention relates to a data transfer system and a data transfer method.

  For example, in a data transfer system in which a root node arbitrates transmission rights such as IEEE 1394, only one device always has the right to use the bus. The data transfer system has a problem that only data transfer between a set of nodes can be performed even when transfer paths do not conflict. One data transfer device that is connected to each other and constitutes the data transfer system is called a node, and a connection form between the nodes is called a topology. The data transfer system has only one root node that performs transmission right arbitration.

  For example, in a data transfer system including nodes A to H as shown in FIG. 1, it is assumed that transfer between node A and node D and transfer request between node G and node H compete. Nodes A to H have three ports for connecting to other nodes for data transfer. The root node is A.

  The data transfer path between node A and node D and the data transfer path between node G and node H do not overlap and do not conflict. However, even if the data transfer paths do not conflict, the data transfer system requests the right to use the bus to the root node A of the bus. Then, only one transfer between the node A and the node D or the transfer between the node G and the node H can be performed. That is, resources related to the transfer bandwidth cannot be effectively used.

  In order to solve such a problem, there is a method in which a bus included in one packet transfer system is divided into a plurality of segments by a switching node and arbitration is performed for each segment when two or more transfer requests compete. (Patent Document 1)

Japanese Patent Laid-Open No. 2001-7819

  However, in this method, there is a limit to the transfer topology, for example, the switching node itself cannot become a leaf.

  A data transfer system having a bus to which a plurality of data transfer devices are connected, selecting one of the data transfer devices as a bus arbitration device, and assigning the right to use the bus to the data transfer device by the bus arbitration device The bus arbitration device includes a topology control circuit that disconnects and restores the connection between the data transfer devices in response to a data transfer request from the data transfer device, and one or more data in accordance with the data transfer request from the data transfer device. And a route proxy permitting unit that outputs a signal that allocates the data transfer device as a proxy bus arbitration device and permits the allocation of the right to use the bus.

  In the present invention, a root bus authority is temporarily assigned to a node in the bus to provide a proxy bus arbitration device. Further, the transfer path between the proxy bus arbitration device, the bus arbitration device, that is, the route node, and another proxy bus arbitration device is temporarily disconnected. As a result, the topology can be flexibly rearranged according to the data transfer status, and a plurality of data transfers can be performed simultaneously.

Conventional data transfer system Block diagram according to the first embodiment Operation flow related to topology change and route proxy authorization Operational flow related to return and judgment of root proxy permission Operation flow related to retention of root proxy permission Operation flow related to retention proxy permission timeout Operation flow when a request for a bus usage right with a transfer record is made Truth table of connection flag register Data transfer system according to the first embodiment Data transfer system according to the second embodiment

<First embodiment>
A block diagram according to this embodiment is shown in FIG. The bus arbitration device according to the present embodiment includes a topology memory circuit TM, a REQ content analysis circuit RA, and a topology control circuit TC.

  The topology storage circuit TM stores the node ID of the device itself and the topology, that is, the position and connection relation of each node constituting the system.

  The topology storage circuit TM assigns numbers to the initial topology, the topology with a connection history, and the current topology, which are the topology immediately after the bus reset, and manages them.

  The topology update signal is input to the topology storage circuit TM in order to store the information related to the latest topology from the topology control circuit TC after the bus reset and the topology change.

  The topology memory circuit TM outputs a now topology signal, which is a signal including the current topology information, to the REQ content analysis circuit RA as information for determination of request content analysis.

  When the valid route proxy permission signal is notified to the REQ content analysis circuit RA, the REQ content analysis circuit RA notifies the topology storage circuit of a hold signal that means topology retention. The effective route proxy permission signal will be described later. When the result signal is notified to the REQ content analysis circuit RA, the topology number topology No. corresponding to the result signal with the connection result stored in the topology storage circuit TM from the REQ content analysis circuit RA. The signal or the hold signal is notified to the topology memory circuit TM. The REQ content analysis circuit RA notifies the topology control circuit TC of an archive topology signal having information related to the requested topology in connection with the information notified from the REQ content analysis circuit RA.

  When the valid route proxy permission signal and the actual result signal are not notified to the REQ content analysis circuit RA, the REQ content analysis circuit RA receives the hold signal and the topology No. Since the signal is not output to the topology storage circuit TM, the topology storage circuit TM does not output the archive topology signal.

  The effective route proxy permission signal is a signal that is notified to the REQ content analysis circuit RA of the root node when any one or more of the nodes included in the data transfer system holds the route proxy permission. While the valid route proxy permission signal is valid, the current topology can be used for transfer. When the valid route proxy permission signal is input to the REQ content analysis circuit RA of the root node, the REQ content analysis circuit RA outputs a hold signal, which is a signal instructing to maintain the topology, to the topology storage circuit TM.

  If the actual signal has been transferred with the same topology before, the actual number is recorded from the topology control circuit TC of the root node. This is a signal input to the REQ content analysis circuit RA of all nodes as a notification signal. The topology connection results are managed by the topology memory circuit TM using the topology number. The REQ content analysis circuit RA of the node provided in the data transfer system uses the topology number notified as the result signal as the topology No. The topology memory circuit TM is notified as a signal.

  The root node REQ content analysis circuit RA examines a method for realizing data transfer for a data transfer request notified as a REQ signal from a node included in the data transfer system. It should be noted that the information on the transfer route, the effective route proxy permission signal, the topology with a connection history, and the current topology is used for the examination of the data transfer implementation method.

  Here, the data transfer realizing method means changing the topology so as to satisfy the request contents. Changing the topology means disconnecting the connection between nodes and issuing a root proxy permission to the node. The operation flow related to the examination of the method for realizing data transfer will be described later.

  When the valid route proxy permission signal is notified to the REQ content analysis circuit RA of the root node, the hold signal is notified from the REQ content analysis circuit RA to the topology storage circuit TM. When the realization method corresponding to the data transfer request requested from the node is a change to a topology with a connection record, the REQ content analysis circuit RA sends a topology No. corresponding to the connection record to the topology storage circuit TM. Signal notification. The topology storage circuit TM outputs an archive topology signal including information related to the requested topology with a connection history to the topology control circuit TC. In this case, the REQ content analysis circuit RA suppresses a new topology signal that notifies the topology control circuit TC of the new topology change content.

  In addition, when the valid route proxy permission signal is continuously notified to the REQ content analysis circuit RA of the root node for a predetermined time or more, the root node REQ content analysis circuit RA notifies the node having the root proxy permission with a holding timeout signal. To do. The hold timeout signal is a signal for notifying a node having root proxy permission for a predetermined time or more to return the root proxy permission.

  When the effective route proxy permission signal is not notified to the REQ content analysis circuit RA of the root node, and when there is no connection record regarding the method of realizing the requested data transfer, the REQ content analysis circuit RA of the root node is new. Consider the topology of. As a result of the examination, if it is determined that simultaneous transfer is impossible, such as a transfer path conflict, a grant (GNT) signal that permits transfer to the node on one side, and a reject signal that rejects transfer on the other node send. If it is determined that simultaneous transfer is possible, a GNT signal is sent to one node and a route proxy permission signal is sent to the other node. Also, the topology change content is notified as a new topology signal to the topology control circuit TC.

  The node to which the route proxy permission signal is notified from the REQ content analysis circuit RA of the root node to the topology control circuit TC is the root proxy node. While the root proxy node has the root proxy authority, the topology control circuit TC outputs a valid route proxy signal.

  Here, the contents of the REQ signal and transfer path signal input to the REQ content analysis circuit RA will be described. The REQ signal is a signal for notifying one value of 0 or 1. When the value of the REQ signal is 1, it means that a transfer request is present. Further, the transfer path signal includes information indicating from which node to which node the transfer request is made.

  The topology control circuit TC of the root node receives the notification of the archive topology signal from the topology memory circuit TM or the new topology signal from the REQ content analysis circuit RA, and changes the connection using the topology change signal to the entire data transfer system. Instruct. In addition, when an archive topology signal is input, a record No. including information on the corresponding topology number is displayed. A notification signal is notified to the entire system. Further, it issues a topology update signal to its own topology storage circuit TM to instruct it to store the new topology.

  Only one of the archive topology signal and the new topology signal is input to the topology control circuit TC of the root node. The topology update signal and the topology change signal output from the topology control circuit TC have the same contents as the signal input to the topology control circuit TC.

  The topology control circuit TC other than the root node is notified of the topology change signal issued from the topology control circuit TC of the root node. The topology control circuit TC of all nodes including the root node disconnects and restores the connection between the nodes according to the topology change signal. A method for connection and restoration between nodes will be described later.

  Next, FIG. 3 shows an operation flow when this embodiment is used. The topology of the entire data transfer system is the same as that of the data transfer system shown in FIG. Further, it is assumed that all nodes included in the data transfer system have the bus arbitration device according to the present embodiment.

  The operation flow shown in FIG. 3 shows that a bus usage right request for data transfer from the node G to the node H and a bus usage right request for data transfer from the node D to the node A are simultaneously transmitted to the root node. It is assumed that A is requested. Transfer paths do not compete for these two bus usage right requests.

  The two bus use right requests are notified from the node G and the node D to the node A which is the root node (S0).

  The REQ content analysis circuit RA of the root node A analyzes the REQ content input from the node G and the node D to the REQ content analysis circuit RA, and determines to which node the GNT signal is issued (S2). In this case, the REQ content analysis circuit of the root node A determines to issue a GNT signal to the node D.

  Next, the REQ content analysis circuit RA has overlapping transfer paths in both the transfer path used for data transfer from the node G to the node H and the transfer path used for data transfer from the node D to the node A. It is determined whether there is any (S4).

  In the system shown in FIG. 1, the transfer path from the node G to the node H and the transfer path from the node D to the node A do not overlap. In the case of this system, if the connection between the node A and the node B and the connection between the node A and the node C are disconnected and the node G is given the root proxy permission, the data transfer from the node G to the node H and the node D to the node Data transfer to A can be realized simultaneously.

  In this case, the REQ content analysis circuit RA of the route node A determines to issue the route proxy permission signal to the node G that has not issued the GNT signal among the nodes D and G that output the REQ signal.

  The topology control circuit TC of the root node A outputs a topology change signal so as to disconnect the connection between the node A and the node B and the connection between the node A and the node C (S6).

  Then, the REQ content analysis circuit RA of the route node A issues a route proxy permission signal to the node G, and the node G temporarily becomes the proxy route node (S8). Then, the node G transfers data to the node H.

  The root node A outputs a GNT signal to the node D (S10). The node D that receives the GNT signal and is permitted to transfer the data transfers the data to the node A.

  When the data transfer is completed, the node G and the node D change the value of the REQ signal from 1 to 0 and notify the root node A that the data transfer is completed (S12, S14). The node G returns the root proxy permission to the root node A (S14).

  When the end of data transfer is notified to the root node device A, the topology control circuit TC of the root node A outputs a topology change signal to return to the original topology (S16). In response to the topology change signal, the connection between the node A and the node B and the connection between the node A and the node C are reconnected to return to the original topology. This completes the data transfer (SE).

  Next, FIG. 4 shows an operation flow in the case where it is determined whether or not to hold the root proxy permission after the data transfer is completed.

  When the value of the REQ signal is continuously output as 1 from the node G, that is, when data transfer is continuously performed from the node G to the node H, the node G does not return the root proxy permission (S20: No). In this case, the node G continues to output an effective route proxy permission signal to the route node A (S22). The REQ content analysis circuit RA of the route node A receives the valid route proxy permission signal and maintains the current topology without outputting the topology change signal (S24). The node G continues to hold the root proxy permission (S30).

  When the node G finishes the data transfer, the node G changes the value of the REQ signal from 1 to 0, and the node G returns the root proxy permission (S20: Yes). In this case, the node G suppresses the effective route proxy permission signal for the route node A and notifies the route node A that the route proxy permission is returned (S26). In response to the return of the root proxy permission and the completion of the data transfer between the node A and the node D, the root node A restores the topology (S28). The process ends here (SE)

  FIG. 5 shows a flow when the node G continues to output the effective route proxy permission signal and the node G holds the route proxy permission.

  After step S30, a request for the right to use the bus between the node G and the node H is notified again from the node G to the root node A (S32). Here, it is determined whether or not the node G has root proxy permission (S34). If the node G does not have the root proxy permission, the process proceeds to step S2 in FIG. 3 (S34: No). When the node G has root proxy permission, data transfer between the node G and the node H is performed with the topology as it is (S36). After the data transfer is completed, it is determined whether or not the route proxy permission is returned again (FIG. 4: S20).

FIG. 6 shows a flow in the case of applying a retention timeout limit by a timer when determining route proxy permission.
The route proxy node determines whether to return the route proxy permission after the data transfer (S20). When there is no data to be continuously transferred at the time of the determination, it is determined that the route proxy permission is returned (S20: Yes). Then, the node G returns the root proxy permission to the root node A (S26). Then, the root node device A restores the topology (S28) and ends the data transfer (SE).

  If there is data to be continuously transferred, the node G does not return the root proxy permission (S20: No, S40). Here, the REQ content analysis circuit RA of the root node checks whether or not the root proxy permission retention timeout limit has been exceeded (S42). Here, when the retention timeout limit is not exceeded (S42: Yes), the node G continues to retain the route proxy permission (S44).

  When the retention timeout limit is exceeded (S46), the root node A outputs a retention timeout signal to the node G. The node G to which the hold timeout signal is input returns the root proxy permission (S46). Then, the root node A restores the connection between the disconnected nodes (S48). The data transfer system returns to the original topology and ends the data transfer (SE).

  FIG. 7 shows a flow for determining the transfer record for the required combination of transfer paths.

  A bus usage right request for data transfer between the node G and the node G and the node H to the root node A and a bus usage right data transfer request for data transfer between the node D and the node A are simultaneously transmitted from the node G to the node G. Notification is made (S50).

  The REQ content analysis circuit RA of the route node A determines whether there is a transfer record corresponding to the data transfer request notified as the REQ signal (S52). When it is determined that there is no transfer record (S52: No), the process proceeds to step S2 in FIG.

  When it is determined that there is a transfer record (S52: Yes), based on the transfer record, the topology control circuit TC of the root node A sends a record No. to the REQ content analysis circuit RA of the subordinate node. A performance signal is notified as a notification signal. The topology control circuit TC of the root node A notifies the topology change signal to the topology control circuit TC of the subordinate node. The following flow is the same as the flow from step S6 to step S10 shown in FIG. The topology control circuit TC of the node A to which the result signal and the topology change signal are input disconnects the connection between the node A and the node B and the connection between the node A and the node C (S6). Further, the route node A issues a route proxy permission signal to the node G based on the transfer record (S8). Node A issues a GNT signal to node D based on the transfer record (S10). Thereafter, the operation is performed according to the flow shown in FIGS.

  It is possible to reduce the processing related to the transfer realization method by storing a proven topology by the topology storage circuit TM and determining and using the transfer record for the required combination of transfer paths.

  The operation for disconnecting and restoring the connection between nodes will be described. In this embodiment, connection between nodes is managed by a connection flag register included in the topology control circuit TC, and disconnection between nodes and restoration of connection are realized.

  A truth table of the connection flag register is shown in FIG. The connection flag register includes registers Physical Port Connection (PPC) [0] to [m−1], Registers Disconnect [0] to [m−1], and Registers Port Connection (PC) [0] to [m−1]. Prepare. Here, m is the number of ports that the node has.

  The register PPC [n] is a register indicating whether or not physical port connection recognition is possible. When no cable is connected to port n of the data transfer device, the value 0 is indicated. An arbitrary integer n represents a port number.

  The register Disconnect [n] is a register indicating port connection release controlled by the topology control circuit TC. Used to release port n connection for simultaneous transfer.

The register PC [n] is a register indicating whether or not the port connection is recognized. When the value of the register is 0, the connection of the port n can be released regardless of the physical connection. . The register PC [n] is 0 when the register Disconnect [n] and the register PPC [n] are 0. By setting the value of the register Disconnect [n] to 0, the value of the register PC [n] is forcibly set to 0. When the value of the register PC [n] is 0, the topology control circuit TC controls, for example, a PHY register that controls a physical connection between data transfer apparatuses existing outside, and releases the connection of the port n. . Thereby, simultaneous data transfer can be realized.
For example, when the value held in the register PPC [n] is forcibly changed and the connection between the nodes is disconnected and restored, the bus reset is not performed according to the IEEE 1394 standard. Occur. When a bus reset occurs, data transfer cannot be performed during that time. Therefore, if the disconnection and restoration of the connection between nodes frequently occur frequently, a bus reset occurs each time, and the transfer efficiency is lowered. According to the method using the register PPC [n] disclosed in the present embodiment, such a decrease in transfer efficiency can be suppressed.

  In the data transfer system shown in FIG. 9, a data transfer request from the node G to the node G and the node H and a data transfer request from the node D to the node D and the node A are simultaneously made to the REQ content analysis circuit RA of the root node A. The operation in the case of the case will be described. In order to perform the simultaneous transfer, the REQ content analysis circuit RA of the root node A determines to disconnect the connection between the node A and the node B and between the node A and the node C. In order to disconnect the connection, the connection of port 0 and port 1 of node A, port 1 of node B, and port 1 of node C may be released.

  The root node A outputs a new topology signal from the REQ content analysis circuit RA, and transmits a topology change signal from the topology control circuit TC to the nodes A, B, and C.

  The nodes A, B, and C change the value of the register Disconnect [1] included in each node from 1 to 0 based on the received topology change signal. For the node A, the value of the register Disconnect [0] is also changed from 1 to 0.

  Since the value of the register Disconnect [1] of the nodes B and C is changed from 1 to 0, the value of the register PC [1] is changed from 1 to 0. As a result, connection is not recognized for port 1 of node B and port 1 of node C. Also, since the values of the registers Disconnect [0] and [1] of the node A are changed from 1 to 0, the values of the registers PC [0] and [1] are changed from 1 to 0. As a result, the connection of port 0 and port 1 of node A is released. As a result, the connection between the node A and the node B and the connection between the node A and the node C are disconnected.

  The operation for restoring the connection will be described. The root node A starts an operation for restoring the connection. The root node A reads the topology before disconnection from the topology storage circuit TM, and outputs a topology change signal to the nodes B and C from the topology control circuit TC.

  The node B and the node C that have received the topology change signal change the value of the register Disconnect [1] from 0 to 1 based on the received topology change signal. Since the value of the register Disconnect [1] becomes 1, the value of the register PC [1] changes from 0 to 1, and the connection is restored.

<Second embodiment>
An apparatus and method for realizing simultaneous data transfer in a data transfer system in which a node including a circuit according to the first embodiment and a conventional apparatus not including the circuit according to the first embodiment coexist will be described.

  Among nodes A to J constituting the data transfer system shown in FIG. 10, nodes A, C, and G are provided with a circuit according to this embodiment, and other nodes are not provided with a circuit according to this embodiment. Suppose that

  In the data transfer system, when the power is turned on, one of the node A, the node C, and the node G that are devices including the circuit according to the present embodiment is set as a root node. This can be realized by turning on the power in order from the node that the power is turned on as the root node. In the following description, a case where node A is the root node will be described.

  In addition, when a bus reset occurs for some reason, in order to prevent one of the devices not including the circuit according to the present embodiment from becoming a root node, the nodes A, C, and N including the circuit according to the present embodiment Force one of G to be a root node. This can be realized by using a force-root signal in, for example, the IEEE 1394 standard.

  In the data transfer system, data transfer from node C to node A, data transfer from node G to node B, data transfer from node F to node H, and data transfer request from node D to node J were made simultaneously. The operation flow in this case is shown below.

At the time of node recognition performed before the data transfer request is made, the root node A recognizes that the nodes B, H, and I are devices including the circuit according to the present embodiment.
A REQ signal for notifying a data transfer request from the nodes C, G, F, and D to the route node A is output.

  The root node A determines that there is no duplicate path in the route of the four transfer requests. Further, the root node A determines that simultaneous transfer is possible by disconnecting the connection between the node A and the node B, the connection between the node A and the node D, and the connection between the node B and the node F. Then, the root node A outputs a GNT signal to the node D and a route proxy permission signal to the nodes B, H, and I that can be the route proxy. In addition, the root node device A outputs a topology change signal, and disconnects the connection between the node A and the node B, the connection between the node A and the node D, and the connection between the node B and the node F.

  The data transfer is completed for all of the data transfer from the node C to the node A, the data transfer from the node G to the node B, the data transfer from the node F to the node H, and the data transfer from the node D to the node J.

  When the data transfer ends, the restoration of the topology and the route proxy authorization are invalidated, and the original topology is restored.

Hereafter, the effect which an Example show | plays is described.
When the node to which the root proxy authority is granted by the route proxy permission signal needs to continuously transfer the data, the effective route proxy signal is notified to the REQ content analysis circuit RA of the root node, so that the route continues. It becomes possible to become a proxy node. As a result, it is possible to reduce determination processing when the same transfer request is generated.

  The topology realized by the topology storage circuit TM is stored and managed by the topology number. Thereby, it is possible to reduce the determination process when the same transfer request as the transfer request made in the past is made.

  When the root proxy authority is monopolized for a long time by a specific node, the topology cannot be changed, and therefore data transfer via the connection between the disconnected nodes becomes impossible. When the root proxy permission signal continues to be notified for a certain time or more, the root proxy authority is returned by notifying the node having the root proxy authority of the hold timeout signal. Thereby, it becomes possible to prevent the root proxy authority monopoly by a specific node.

  Hereinafter, various aspects of the invention will be summarized as additional notes.

<Appendix 1>
Data having a bus to which a plurality of data transfer devices are connected, selecting one of the data transfer devices as a bus arbitration device, and assigning a bus use right to the data transfer device by the bus arbitration device A transfer system,
The bus arbitration device, in response to a data transfer request from the data transfer device, a topology control circuit that disconnects and restores the connection between the data transfer devices;
In response to a data transfer request from the data transfer device, one or more of the data transfer devices are assigned as proxy bus arbitration devices, and a route proxy permission unit that outputs a signal that allows permission to use the bus A data transfer system comprising:
<Appendix 2>
The proxy bus arbitration device is a signal that suppresses disconnection and restoration of the connection between the data transfer devices by the topology control circuit and assignment as a proxy bus arbitration device to the data transfer device by the route proxy permission unit. The data transfer system according to appendix 1, further comprising an effective proxy bus arbitration unit that outputs
<Appendix 3>
The bus arbitration device is configured to disconnect and restore the connection between the data transfer devices by the topology control circuit in response to a request from the data transfer device, and to perform the route proxy permission unit in response to a request from the data transfer device. The data transfer system according to appendix 1 or 2, further comprising a topology storage circuit that stores and manages assignment of the proxy bus arbitration device to one or a plurality of the data transfer devices.
<Appendix 4>
The bus arbitration device, after allocating the data transfer device as the proxy bus arbitration device, forcibly outputs a signal for canceling the allocation as the proxy bus arbitration device after a predetermined time has elapsed. 4. The data transfer system according to appendix 2 or 3, further comprising a limiting circuit.
<Appendix 5>
A data transfer method in which a plurality of data transfer devices are connected by a bus, one of the data devices is selected as a bus arbitration device, and the bus arbitration device assigns a right to use the bus to the data transfer device. And
In response to a data transfer request from the data transfer device, disconnecting and returning the connection between the data transfer devices;
Allocating one or a plurality of the data transfer devices as proxy bus arbitration devices in response to a data transfer request from the data transfer device, and permitting the allocation of the right to use the bus. Data transfer method.
<Appendix 6>
Item 6. The supplementary note 5, comprising the steps of suppressing disconnection and restoration of the connection between the data transfer devices and assignment of the route proxy permission unit as a proxy bus arbitration device to the data transfer device. Data transfer method.
<Appendix 7>
Disconnection and restoration of connection between the data transfer devices in response to a request from the data transfer device, and assignment as one or more of the data transfer devices as the proxy bus arbitration device in response to a request from the data transfer device The data transfer method according to appendix 5 or 6, further comprising a step of storing and managing.
<Appendix 8>
The method according to claim 6 or 7, further comprising the step of forcibly canceling the assignment as the proxy bus arbitration device after a predetermined time has elapsed after the data transfer device is assigned as the proxy bus arbitration device. The data transfer method described in 1.

TM topology memory circuit RA REQ content analysis circuit TC topology control circuit

Claims (8)

It has a bus a plurality of data transfer devices are connected, one of the data transfer device of the plurality of data transfer devices selected as the bus arbiter, the bus to the plurality of data transfer apparatus by the bus arbitration device Data transfer system to assign usage rights for
The bus arbitration system, according to a plurality of data transfer requests from said plurality of data transfer devices, and topology control circuit for cutting and return the connection between the plurality of data transfer devices,
When there is no overlapping path in each data transfer path corresponding to the plurality of data transfer requests, at least one data transfer apparatus among the plurality of data transfer apparatuses is assigned as a proxy bus arbitration apparatus, and data transfer system characterized by having; and to Lulu over preparative proxy authorization unit to allow the permission assignment. The proxy bus arbitration device disconnects and returns the connection between the plurality of data transfer devices by the topology control circuit, and the proxy to at least one data transfer device among the plurality of data transfer devices by the route proxy permission unit The data transfer system according to claim 1, further comprising an effective proxy bus arbitration unit that outputs a signal that inhibits assignment as a bus arbitration device. The bus arbitration device forcibly serves as the proxy bus arbitration device after a predetermined time has elapsed after allocating at least one data transfer device of the plurality of data transfer devices as the proxy bus arbitration device. The data transfer system according to claim 2, further comprising a holding time limit circuit that outputs a signal for canceling the allocation. The route proxy permitting unit allocates a data transfer device that has made the data transfer request among the plurality of data transfer devices as the proxy bus arbitration device, and allows permission to allocate the right to use the bus. The data transfer system according to any one of claims 1 to 3. A plurality of data transfer devices are connected by a bus, and one of the plurality of data transfer devices is selected as a bus arbitration device, and the bus arbitration device uses the bus to the plurality of data transfer devices. A data transfer method for assigning
Depending on the plurality of data transfer requests from said plurality of data transfer devices, the steps of the cutting and return the connection between a plurality of data transfer devices,
When there is no overlapping path in each data transfer path corresponding to the plurality of data transfer requests, at least one data transfer apparatus among the plurality of data transfer apparatuses is assigned as a proxy bus arbitration apparatus, and A data transfer method comprising: a step of permitting allocation. Characterized in that it has a step of inhibiting the assignment on behalf bus arbitration device to at least one data transfer device, the one of the the cutting and return connections between the data transfer apparatus, prior Symbol plurality of data transfer devices The data transfer method according to claim 5.   Disconnection and restoration of connection between the data transfer devices in response to a request from the data transfer device, and assignment as one or more data transfer devices as the proxy bus arbitration device in response to a request from the data transfer device 7. A data transfer method according to claim 6, further comprising a step of storing and managing.   6. The data transfer device that has made the data transfer request among the plurality of data transfer devices is assigned as the proxy bus arbitration device so that assignment of the right to use the bus can be permitted. The data transfer method according to any one of?

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