JP4005968B2 - Data transmission system - Google Patents

Description

  The present invention relates to a data transmission system comprising a plurality of CSMA / CD media access control transmission / reception control systems in which a plurality of terminals having a data frame transmission / reception function are connected in a star shape to ports of a hub device.

  The IEEE 802.3 standard represented by Ethernet (registered trademark) and the ISO 8802/3 standard (hereinafter represented by IEEE 802.3), which is the mainstream of the current LAN, are CSMA / CD (Carrier Sense Multiple Access / Collision). Media access control called an example of abbreviation LAN for Detection) is performed. In CSMA / CD, each terminal (each station device) monitors a signal on a common transmission path, and transmits if there is a vacancy for a certain period of time. Also, during the transmission, it is monitored whether there is a collision with another terminal, and if a collision occurs, the transmission is interrupted and transmitted again after a predetermined time delay. Due to such CSMA / CD operation, when the usage rate of the transmission path is increased, collisions frequently occur or transmission may not be performed indefinitely. Therefore, it is not suitable for applications that require real-time performance.

  In order to realize real-time property that information can be exchanged surely within a certain time, the present applicant has a CSMA / CD system in which a plurality of terminals having a data frame transmission / reception function are connected in a star shape to a port of a hub device Previously proposed a data transmission apparatus (Japanese Patent Application No. 8-51984).

  FIG. 10 is a system diagram showing a schematic configuration of the data transmission device of the prior application. This is achieved by adding a new function to the hub device of the IEEE 802.3 standard so that each terminal can be surely connected within a certain time. This is a hub device (denoted as a real-time hub device) that gives the right to use the transmission path and enables mutual information exchange.

10 includes a real-time hub device (hereinafter simply referred to as a hub device) 100, a plurality of terminals 50 having a transmission circuit conforming to the IEEE 802.3 standard, and a transmission cable 40. . Each terminal 50 is connected to the ports 1, 2, 3,... In the star type data transmission apparatus, the hub apparatus 1 is connected to the IEEE 502.3 standard terminal 50 connected to each port of the hub apparatus 100 and arranged in a star shape.
The transmission permission control function of 00 repeats giving the transmission permission 50 to each terminal, for example, one station at a time, or in accordance with a predetermined order, and accordingly, a certain terminal 50 is a plurality of times and a certain terminal. 50 is skipped or repeated several times once, giving priority to the method of granting transmission permission, and the transmission permission given to each terminal is the number of frames that can be transmitted at one time, The transmission time is controlled, and the transmission right is obtained within a certain time.

  FIG. 11 shows the timing of transmission permission control in the hub device 100 of FIG. In the transmission permission control of the hub device 100, the hub device 100 transmits a preamble signal (PRE in FIG. 11 in a dummy frame) including no data information to all the terminals 50 except for a specific terminal. A terminal other than one terminal cannot transmit a data frame (DT in FIG. 11). The free time between the preamble signal PRE and the data frame DT is the free time between frames defined by the IEEE 802.3 standard so that the terminal does not shift to the data frame sending operation by detecting the no-signal state of the transmission path (for example, 10 Mbps and a value smaller than 9.8 μs of IEEE 802.3 standard). When transmission of one specific terminal is completed, the transmission path usage right is transferred to this terminal by transmitting a dummy frame PRE to all terminals other than another terminal. By repeating this operation one terminal at a time or in a predetermined order, or in addition, a certain terminal skips, or repeats once or several times, etc., so that each terminal acquires a transmission right periodically. be able to.

  Further, the time that each terminal 50 can transmit at one time is monitored, the transmission permission time is calculated from the difference between the current transmission start time from the previous transmission start time and the target transmission right circulatory time. At the end of the data frame DT, the transmission right is transferred to the next terminal, so that the circulatory time of the transmission right is made substantially constant.

  In the real-time hub device 100 of the prior application described above, when the number of terminals 50 is increased or when the terminals 50 are distributed over a wide range, the real-time hub device 100 itself needs to be large, The transmission cable 40 between the terminal 50 and the port of the real-time hub device 100 distributed in the network becomes longer, and the wiring cost of the transmission cable 40 for compensating for signal attenuation and eliminating the influence of noise on the transmission cable 40 increases. In particular, when a terminal is installed for each vehicle and signal lines need to be routed between vehicles, such as a data transmission device mounted on a train, the signal lines are concentrated on a single real-time hub device. It is not preferable for use.

  That is, each vehicle is separated as necessary and connected to another vehicle to form one train, so that the centralized real-time hub device can be combined with the flexibility of train organization. It is difficult to wire signal lines.

  Therefore, the functions of the real-time hub devices are distributed, and a plurality of real-time hub devices (hereinafter simply referred to as hub devices) are distributed and arranged in necessary places such as in one vehicle, and the distance between the hub device ports and terminals is short. It is only necessary to connect a plurality of hub devices that are connected by signal lines having a length and are connected to each other so that a plurality of hub devices can be integrated to function as a single hub device. .

  An object of the present invention is to provide a data transmission system in which a plurality of hub devices are connected to each other so that transmission right control can be performed in real time even if the hub devices of the star type data transmission device of the prior application are dispersedly arranged. Is to realize.

To achieve the above object, the invention corresponding to claim 1 comprises at least three hub devices, all of which have the same configuration, and the hub devices are connected to each other by a serial signal transmission line. The mutual control of the hub devices is performed by a communication protocol on the serial signal transmission path, and the hub devices operate as if they were one hub device,
A port of each hub device includes a transmission / reception control system in which a plurality of terminals each having a data frame transmission / reception function of IEEE 802.3 standard are connected in a star shape,
The transmission of data frames from the terminal to which one hub apparatus corresponds to each of the hub apparatuses in a predetermined order with respect to the respective ports, and with respect to the terminals connected to the respective hub apparatuses. Means for performing transmission permission control, wherein the means for performing transmission permission control receives a transmission path control right transfer signal indicating a transmission path control right to start the transmission permission control, and completes transmission permission control. The transmission line control right transfer signal can be sent to another downstream serial signal transmission line, and the transfer of the transmission line control right transfer signal to the previous downstream hub device is confirmed. A confirmation means for confirming that the transmission path control right is transferred from the side or downstream side to the upstream side hub device,
The terminal sets the transmission path control right transfer signal as a non-signal with a significant time length following the preamble signal of the IEEE 802.3 standard, and a response to the transmission path control right transfer signal sent from one downstream hub device. The data transmission system is characterized in that the confirmation is configured as a preamble signal of the standard or a data frame of the standard.

In order to achieve the above object, the invention corresponding to claim 2 comprises at least three hub devices, all of which have the same configuration, and the hub devices are connected to each other by a serial signal transmission line. The mutual control of the hub devices is performed by a communication protocol on the serial signal transmission path, and the hub devices operate as if they were one hub device,
A port of each hub device includes a transmission / reception control system in which a plurality of terminals each having a data frame transmission / reception function of IEEE 802.3 standard are connected in a star shape,
The transmission of data frames from the terminal to which one hub apparatus corresponds to each of the hub apparatuses in a predetermined order with respect to the respective ports, and with respect to the terminals connected to the respective hub apparatuses. Means for performing no transmission permission control,
The means for performing the transmission permission control receives a transmission path control right transfer signal indicating a transmission path control right for starting the transmission permission control, and when the transmission permission control is completed, the transmission path control right transfer signal is transmitted to the downstream side. Can be sent to another serial signal transmission line, confirms the transfer of the transmission path control right transfer signal with the previous downstream hub apparatus, and transfers from the upstream side to the downstream side or from the downstream side to the upstream side hub apparatus. Confirmation means for confirming that the transmission path control right has been transferred;
After sending the transmission path control right transfer signal to the downstream serial signal transmission line, the delivery confirmation from the downstream side is monitored for a specified time, and if there is no response to the delivery confirmation, the transmission line control right transfer signal is sent. And means for stopping
The terminal sets a transmission path control right transfer signal as a no-significant time length signal following the IEEE 802.3 preamble signal, and confirms a response of the transmission path control right transfer signal sent from one downstream hub device. Configure as a preamble signal of the standard or a data frame of the standard,
When the hub device stops sending the transmission path control right transfer signal, a situation where there is no transmission path control right temporarily occurs, and then the transmission path control is performed again from the upstream side to the downstream hub apparatus. A data transmission system characterized by transferring rights.

  According to the present invention, the following effects can be obtained.

  (1) A data transmission system conforming to the IEEE 802.3 standard having no time determinism can be given time determinism by a real-time hub device, and further, the functions of the real-time hub device can be distributed and geographically distributed.

  (2) It is possible to avoid the collision of the IEEE 802.3 standard, so that the transmission efficiency is increased, and the distance extension between terminals and the circulation time of the transmission path control right can be easily programmed including the circulation in the hub device. .

  (3) In order to realize a distributed arrangement, the timing at which transmission permission control can be performed on the port of the hub device is transferred as a transmission path control right transfer signal, and further, control is performed so that the transfer can be repeated. Any of the signals used in the IEEE 802.3 standard signal can be used, and since it can be realized in conformity with the IEEE 802.3 standard, the standard of the IEEE 802.3 standard that is widely used is used. Since it can be easily realized as a method that is consistent with the standard, such as connection with terminals, equipment, diversion of the standard, etc., the hardware cost can be set at a low cost, and the hub device as in the embodiment of the present invention By preparing terminal functions inside and enriching the microcomputer software, it is possible to embed detailed data transmission equipment. Can be realized according to function and cost.

  (4) Although the hub device is described as a concentrator (collector / distributor) of a plurality of terminals, as described above, this system can use general-purpose and inexpensive products, and can integrate hard logic. The use of a programmable gate array can be realized in a compact manner. In that case, it can be realized as a hub device for a single terminal (which is no longer meaningful as a hub device as a function of collecting and wiring), and a physical layer having a bus structure conforming to the IEEE 802.3 standard is provided. , Real-time, bus, physical layer can be replaced.

  (5) By configuring as a data transmission system management function as a multiplexed data system, for example, a duplex data system, it is possible to realize a system that pursues very high operation continuity. (6) Since the two separated data transmission devices can be physically combined and integrated in one cycle of the transmission cycle, the microcomputer program installed in the hub device can be partially integrated. It is possible to manage normal parts and combine them flexibly and continue operation as a new data transmission system.

  According to the present invention, even if the hub device of the star type data transmission device is distributed, it is possible to perform transmission right control with real time as a whole.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1 is a system diagram showing a first embodiment of the present invention, comprising a plurality of transmission / reception control systems, for example, four star type data transmission apparatuses shown in FIG. A CSMA / CD media access control system in which a plurality (two or three in the figure) of terminals 50 having a transmission / reception function are connected to the ports of the hub devices 101, 102, 103, and 104 in a star shape, respectively. The hub devices 101 to 104 are connected by a pair of signal transmission paths 3 and 4 in opposite directions, and at one point, a data frame from a terminal to which one of the hub devices 101 to 104 corresponds. In this data transmission system, transmission permission control is performed to enable transmission to each port in a predetermined order.

  Here, for convenience of explanation, the hub device 101 is described as the upstream side, and the hub device 104 is described as the downstream side.

  In the data transmission system having such a configuration, the data frame sent from the terminal 50 connected to the hub devices 101 to 104 can be sent to the upstream, downstream, or upstream / downstream signal transmission path. , 4 can be relayed to the terminal via the port, the data frame received from the upstream can be relayed downstream, and the data frame received from the downstream can be relayed to the upstream signal transmission path. At one point, among the plurality of hub devices, one hub device performs the above-described transmission permission control, so that the plurality of hub devices are connected in sequence, and the plurality of hub devices are as if one hub device. Thus, data exchange between terminals connected to a plurality of hub devices can be performed.

  FIG. 2 is a block diagram for explaining the hardware of the hub device 102 among the hub devices 101 to 104 in FIG. 1. The other hub devices 101, 103, and 104 are all configured in the same manner as the hub device 102. Therefore, the description thereof is omitted.

  As will be described below, the gate circuits A1, A2, A3, A4, A5, A6, the timer circuit (Token-Det Timer) 8 and the hub state control circuit (Hub-State-CON) that constitute the relay control means. ) 12 and a transmission stop means comprising a timer circuit (Token-Ack Timer) 10 and a hub state control circuit 12.

  The transceiver circuit (TECV-L) 1 is connected to the upstream signal transmission paths 3L and 4L, and the transceiver circuit (TECV-R) 2 is connected to the downstream signal transmission paths 3R and 4R. Between the hub common bus 5 and the transceiver circuit 1, there are gate circuits A1, A2, A3 whose output signals are controlled by control signals S1, S2, S3, respectively. Connected between the hub common bus 5 and the transceiver circuit 2 are gate circuits A4, A5 and A6 whose output signals are controlled by control signals S4, S5 and S6, respectively.

  Here, by activating the control signal S1 of the gate circuit A1, a significant signal received from the upstream side can be guided to the hub common bus 5, and by activating the control signal S4 of the gate circuit A4, A significant signal received from the downstream side can be guided to the hub common bus 5. In this case, one of the control signals S5, S6 and S2, S3 of the gate circuits A5, A6 and A2, A3 is active, or all of them are inactive. By making the control signals S2 and S5 of the gate circuits A2 and A5 active, signals on the hub common bus 5 can be output to the upstream or downstream signal transmission paths 3L and 4L or 3R and 4R. Further, when the control signals S3 and S6 of the gate circuits A3 and A6 are active, the signal can be relayed from the downstream side to the upstream side or from the upstream side to the downstream side.

  The significant signal detection circuit (RCCVDET1) 6 outputs a significant signal detection signal Rcdl when detecting a significant signal from the upstream side of the transceiver circuit 1, and the significant signal detection circuit (RCCVDET2) 7 is downstream of the transceiver circuit 2. When a significant signal from the side is detected, a significant signal detection signal Rcd2 is output.

  The timer circuit 8 measures the length of the transmission path control right transfer signal received from the upstream side, and outputs the timing signal Tkd after the lapse of the significant time measurement.

  The timer circuit (Tif-Trunk Timer) 9 measures the no-signal time of the significant signal detection signal Rcdl of the upstream significant signal detection circuit 6 and the no-signal time of the significant signal detection signal Rcd2 of the downstream significant signal detection circuit 7. When the no-signal time is measured, a timing signal TifT having an elapsed time shorter than the no-signal time of the ISO 802.3 standard is output.

  A timer circuit (Token-Ack Timer) 10 monitors a response confirmation after sending a transmission path control right transfer signal downstream, outputs a timing signal TAK1 for confirming a reception response from the downstream, and A detection waiting time lapse signal TAK2 is output when there is no reception response from the downstream.

  The timer circuit (No. 1 Signal Timer) 11 measures the no-signal detection time on the upstream and downstream signal transmission paths, and as a result of the most downstream hub device giving up the transmission path control right, When a no-signal state occurs and a predetermined time Tns1 elapses, the hub apparatus obtains a transmission path control right and outputs a timing signal nsl for starting transmission of a transmission right holding signal, assuming that there is no significant signal input. Further, assuming that there is no significant signal input, the timing signal ns2 is output as the count value of the predetermined time Tns2. The most upstream hub device outputs a transmission right holding signal for the predetermined time Tns2.

  On the input side of the timer circuits 8, 9, 10, 11 are signals RT1, RT2, RT3, RT4 output from the hub state control circuit (Hub-State-CON) 12 and functioning as reset signals and input switching signals, respectively. Entered.

  The transceiver circuits (TRCV1... TRCVn) 131... 13n conform to the IEEE 802.3 standard and correspond to the port Port-1. A terminal 50 is connected to the end of each port Port-1... Port-n. The output signal from each terminal 50 is Port-1 In... Portn In, and the output signal from each port Port-1... Port- n is Port-1 Out. Transceiver circuits 131... 13 n obtain output signals PI 1... PIn based on output signals Port-1 In. The output signals PI1... PIn of the transceiver circuits 131... 13n are respectively input to the significant signal detection circuit (RCCVDTC10) 22, and the input signals from the transceiver circuits 131. The port input signal RIN is selected, and the port input signal RIN is input to the hub state control circuit 12.

  The port input signal RIN is guided to a timer circuit (Tif-Timer) 19 that measures a no-signal period between data frames. The timer circuit 19 outputs a timing signal Tifh having an elapsed time shorter than the no-signal time, and the timing signal Tifh is input to the hub state control circuit 12.

  The output signals PI1... PIn of the transceiver circuits 131... 13n are sent to the hub common bus 5 via the gate circuits B1... Bn by activating the control signals SB1. Signals from the hub common bus 5 are guided and gate signals C1... Cn output signals PI1... PIn are output controlled by activating control signals SC1. The signals are input to the transceiver circuits 131... 13 n through the circuits C 1... Cn, are output from the ports Port 1.

  The preamble signal generation circuit (Preamble-GEN) 20 generates a preamble signal when the control signal Pag from the hub state control circuit 12 becomes active, and when the control signal S7 becomes active, the preamble signal is generated via the gate circuit A7. Is output to the hub common bus 5.

  A clock signal generation circuit (Clock-GEN) 21 generates a clock signal used in the hub device.

  The transceiver circuit (TRCV-kT) 14 is connected to the microcomputer common bus 23 via the run transmission control circuit (LANC) 15 in accordance with the IEEE 802.3 standard. The run transmission control circuit 15 and the transceiver circuit 14 allow the hub device to communicate with all terminals connected to the data transmission device and other hub devices using IEEE 802.3 standard frames.

  The register (REGS) 16 is for holding control parameters of the hub device and the data transmission device. The microcomputer (μPU Timer + RAM / ROM) 17 includes a microprocessor, a timer as its peripheral circuit, a RAM memory, and a ROM memory for storing a control program.

  An input / output register circuit (I / O-REG) 18 of the microcomputer 17 is used for inputting the state of each hardware part, the timer value of the timer circuit, and the output for direct control of the hardware, but the details are omitted.

  The LAN transmission control circuit 15, the register 16, the input / output register circuit 18, the hub state control circuit 12, and the microcomputer 17 are connected to the microcomputer common bus 23, respectively.

  Next, timing control of the hub device is performed by the hub state control circuit 12, which will be described with reference to FIG. FIG. 3 shows the timing of transfer of the transmission path control right and the acquisition of the transmission path control right. A no-signal state exceeding the time of the timing signal TAK1 is detected following the data frame from the hub device on the upstream side. This is performed as the timing signal Tkd from the timer circuit 8 by the significant signal detection circuit 6 described above.

  On the other hand, the timer circuit 9 similarly detects the absence of the timing signal TifT, and the timing signal TifT is output. The control signal pag from the hub state control circuit 12 is activated by the timing signal TifT so that the no-signal time of the IEEE 802.3 standard is not exceeded, the preamble signal is generated from the preamble signal generation circuit 20, and the control signal of the gate circuit A7 S7 is activated and output on the hub common bus 5, the control signal SCj of the gate circuit Cj and the control signal S5 of the gate circuit A5 become active, and are output downstream by the port and the transceiver circuit 2 by TRCV-j. .

  As the timing signal TAK1, the transmission path control right holding flag becomes active. From this point of time, the preamble signal is returned to the upstream hub device as a reception response signal of the transmission path control right transfer signal. The preamble on the hub common bus 5 is output to the upstream signal transmission path 3L by the transceiver circuit 1 when the control signal S2 of the gate circuit A2 becomes active.

  When the transmission control right holding flag becomes active, transmission permission control is started. The preamble signal output to Port-1 is cut by deactivating the control signal SC1 of the gate circuit C1. The terminal 50 of the IEEE 802.3 standard connected to Port-1 detects a no signal on the signal path, and can output a data frame.

  In FIG. 3, when one frame of data frame is received from port 1 and this is detected as PI1, the input of RIN is detected via the transceiver circuit 22, the control signal S7 of the gate circuit A7 is inactive, and the control signal of the gate circuit B1 By making SB1 active, a data frame from Port-1 is output on the hub common bus 5 instead of a preamble signal, and the data frame is relayed to all ports and upstream and downstream sides. Transmission permission control grants transmission permission to Port-1, Port-2,... And repeats data frame relay.

  FIG. 4 shows the timing of transfer of the transmission path control right and transfer of the transmission path control right. When the hub apparatus holding the transmission right completes the transmission path permission control, the control signal S2 of the gate circuit A2 and the control signal S5 of the gate circuit A5 are deactivated, so that the upstream and downstream signal transmission paths are set. No signal state.

  On the other hand, by outputting a preamble to the hub common bus 5, a preamble signal is output to the port. The data frame following the preamble signal is received after the timing signal TAK1 + control delay + propagation delay time from the downstream side by the transmission channel control right acquisition sequence described above. By detecting this by the significant signal detection circuit 7, the control signal S7 of the gate circuit A7 is made inactive, and the control signal S4 of the gate circuit A4 is made active so that the received frame from the downstream side is placed on the hub common bus 5. Is output and relayed to the port. Further, when the control signal S3 becomes active in the gate circuit A3, the signal from the downstream side is relayed to the upstream side.

  FIG. 5 shows the timing of transfer of the transmission path control right in the most downstream side hub device and the no-signal detection timing in each hub device. When transmission permission control is completed, no signal is output downstream. The transmission response of the transmission path control right transfer signal from the downstream side is monitored by the timing signal TAK2. Using the timing signal TAK2 from the timer circuit 10, the transmission path control right holding flag becomes inactive.

  On the other hand, a preamble is output on the hub common bus 5. The timer circuit 11 detects that there is no signal on the upstream and downstream signal transmission paths, and the transmission path control right is acquired using the signal nsl as a timing.

  FIG. 6 shows the transfer right transfer timing from the most downstream side hub device to the most upstream side hub device in order to transfer the transfer control right to the most upstream side hub device and avoid competition. Each of the hub devices 101 to 104 outputs a preamble signal upstream and downstream for Tns 2 hours, assuming that a transmission right has been acquired after Tnsl time. When a preamble signal is received as a significant signal from the upstream during output, the transmission path control right holding flag is deactivated and the transmission of the preamble signal is stopped, and the signal input from the upstream side is relayed, so that the hub device is in the time of Tns2 Contention between them is avoided and the data frame following the preamble from the most upstream hub device is received by each hub device.

  When two separated data transmission devices are integrated, the control signal S5 of the gate circuit A5 and the control signal S3 of the gate circuit A3 are sent to the hub device on the most downstream side of one data transmission device. By making it inactive, the transmission cuts to the downstream signal transmission paths 3R, 4R and the signal relay cuts from the downstream side are performed, and the upstream signal transmission path of the hub device located at the uppermost stream of another data transmission apparatus And a signal transmission path on the downstream side of the hub device. The most downstream hub device receives the transmission path control right transfer signal, performs transmission permission control, generates a transmission path control right transfer signal to the downstream side, and controls the control signal S5 of the gate circuit A5 and the control of the gate circuit A3. By making the signal S3 active, the transmission cut to the downstream side and the signal relay cut from the downstream side are canceled, and the significant signal from the downstream transmission system is guided to the upstream side.

<Second Embodiment>
FIG. 7 is a system diagram showing the configuration of a data transmission system in which the first data transmission system is duplicated, and FIG. 8 is a diagram showing a connection state of mutual signals between hub devices of the data transmission system. 9 shows an example of reconfiguration in which an abnormal part is avoided in the data transmission system. In this case, an example of a situation in which the data transmission system is integrated and reconfigured using normal components of each data transmission apparatus partially including an abnormality is shown.

  In FIG. 9, # 11 to # 15 constitute an active system, and # 21 to # 25 constitute a standby system. In FIG. 9A, for example, when the active # 11 hub device becomes abnormal, # 12 to # 15 are configured as new data transmission devices. When an abnormality occurs in the active system in this way, the standby system is used. However, regarding the # 23 of the standby system or an abnormality occurs in the signal transmission path between # 23 and # 22, similarly, # 21 and # 21 are used. When the 22 systems are separated, the # 12 to # 15 systems and the # 21 # 22 systems are integrated by the above-described sequence.

  In FIG. 9B, for example, an abnormality has occurred in the signal transmission path between # 13 or # 12 and # 13 of the active system, and # 21 of the standby system has been disconnected due to an abnormality or the like. , # 12 and # 22, # 23, # 24, # 25 are integrated. In the example of FIG. 9A, the systems # 21 and # 22 are upstream systems, and in the example of FIG. 9B, the system # 11 # 12 is an upstream system.

  FIG. 9C shows a case where # 25 further becomes abnormal in the system in the state of FIG. 9B. In this situation, since # 14 and # 15 were in operation as separated data transmission devices, the data transmission device consisting of # 11, # 12, # 22, # 23, and # 24 and # 14, # 15 Further, the data transmission device is further integrated. In these cases, the two hub devices of the data transmission device are connected to each other.

  In order to configure such a duplicated data transmission system, two sets of signal transmission paths 3 and 4 are controlled by switches SW1 and SW2 as shown in FIG. 8 in contrast to the hardware configuration example of FIG. What is necessary is just to add the structure which can be selected with signal SL1, SL2. FIG. 8 shows this situation, for example, with the upper side being the active system and the lower side being the standby system. The control signals SL1 and SL2 are output from the input / output register circuit 18. When two sets of data transmission systems are used as the active system and the standby system, the location of the hub device or signal transmission path that is in an abnormal state or disconnected is managed. These pieces of information can be shared by exchanging messages with each other by the transceiver circuit 14, the LAN control circuit 15, and the microcomputer 17 of the hub device. Even if some hub devices or signal transmission paths in the active system and standby system become abnormal, the hub device is used on the upstream and downstream sides to maintain the operation as a whole using the remaining normal components. The two data transmission systems described above are integrated by using the switch SW1 or SW2 to switch between the two sets of signal inputs of the current and bypass and the two sets of signal outputs of the current and bypass as the signal transmission path. It can be realized by a sequence.

  In FIG. 9A, at # 12, the transmitters 115 and 117 and the transmitters 112 and 114 shown in FIG. 8 are selected. In # 22, signal transmission paths 111, 113, 116, and 118 are selected. In the example of FIG. 9B, in # 12, the opposite of FIG. 9A, that is, 111, 113, 116, and 118 are selected. Also in # 22, 115, 117, 112, and 114 are selected. Similarly, in the case of FIG. 9C, a signal transmission path for input and output is selected, but the description is omitted.

<Modification>
The present invention is not limited to the above-described embodiment, and can be implemented similarly not only in a wireless communication system but also in a wired communication system or an optical communication system as a signal transmission path between hub devices.

  In the above-described embodiment, the hub device is described as a concentrator (collector / distributor) of a plurality of terminals. However, as described above, general-purpose and inexpensive products can be used, and hard logic can be integrated. A programmable gate array or the like can be used.

1 is a system diagram for explaining a first embodiment of a data transmission system of the present invention; FIG. The block diagram for demonstrating the hardware which shows an example of the hub apparatus of FIG. The figure for demonstrating delivery of the transmission-line control right of the data transmission system of FIG. 1, FIG. 2, and acquisition of the transmission-line control right. The figure for demonstrating delivery of the transmission-line control right of the data transmission system of FIG. 1, FIG. 2, and transfer of the transmission-line control right. The figure for demonstrating delivery of the transmission-line control authority of the data transmission system of FIG. 1, FIG. 2, and a most downstream hub apparatus. FIG. 3 is a diagram for explaining transfer path control right delegation and conflict avoidance to the most upstream hub device of the data transmission system of FIGS. 1 and 2; The systematic diagram for demonstrating 2nd Embodiment of the data transmission system of this invention. The figure for demonstrating the mutual signal connection between the hub apparatuses of FIG. The figure for demonstrating the reconfiguration example which avoided the abnormal part in the duplex data transmission system of FIG. The system diagram which shows an example of the star type data transmission apparatus of a prior art example. The figure for demonstrating the example of a transmission timing of the star type data transmission apparatus of FIG.

Explanation of symbols

1 ... Transceiver circuit (TECV-L), 2 ... Transceiver circuit (TECV-R)
3L, 4L ... upstream signal transmission path, 3R, 4R ... downstream signal transmission path, A1 to A7 ... gate circuit, B1 to Bn ... gate circuit, C1 to Cn ... gate circuit, S1 to S7 ... control signal, SB1 SBn: control signal, SC1 to SCn: control signal, 5: hub common bus, 6: significant signal detection circuit (RCVDET1), 7: significant signal detection circuit (RCVDET2), Rcd1 ... significant signal detection signal, Rcd2 ... significant signal detection Signal, 8 ... Timer circuit (Token-Det Timer), Tkd ... Time-elapsed timing signal, 9 ... Timer circuit (Tif-Trunk Timer) for measuring upstream and downstream no-signal time, TifT ... IEEE802.3 standard Timing signal with elapsed time shorter than no signal time. 10: Timer circuit (Token-Ack Timer) for confirming and monitoring response after releasing transmission path control transfer signal downstream, TAK1 ... Timing signal for confirming reception response from downstream, TAK2 ... Reception response from downstream Detection waiting time elapse signal when there is not, 11... Timer circuit (No-Signal Timer) for measuring no signal detection time on upstream and downstream signal transmission paths, Tns1... Timing signal, Tns2. State control circuit (Hub-State-CON), 13 ... IEEE802.3 standard transceiver circuit (TRCV1 to TRCVn), 14 ... IEEE802.3 standard transceiver circuit (TRCV-kT), 15 ... LAN control circuit (LANC) ), 16... Register (REGS), Port 1 to Po tn: port of the hub device, Tifh: timing signal with an elapsed time shorter than the no-signal time of the IEEE 802.3 standard, 17: microcomputer (including μPU Timer + RAM / ROM), 18: input / output register circuit (I / I) of the microcomputer O-REG), 19... Timer circuit (Tif-Timer) for measuring a no-signal period between data frames, 20... Preamble signal generation circuit (Preamble-GEN), 21... Clock signal generation circuit (Clock-GEN), 22 ... Significant signal detection circuit (RCVDETC10), RT1 to RT4... Reset signal and on / off switching signal of timer circuits 8 to 11, SEL... Input signal selection signal, RIN.

Claims (4)

At least three hub devices are provided, all of the hub devices have the same configuration, and the hub devices are connected to each other by a serial signal transmission line, and the control of the hub devices is performed by communication on the serial signal transmission line. Each hub device operates according to a protocol, and operates as if it is a single hub device,
A port of each hub device includes a transmission / reception control system in which a plurality of terminals each having a data frame transmission / reception function of IEEE 802.3 standard are connected in a star shape,
The transmission of data frames from the terminal to which one hub apparatus corresponds to each of the hub apparatuses in a predetermined order with respect to the respective ports, and with respect to the terminals connected to the respective hub apparatuses. Means for performing transmission permission control, wherein the means for performing transmission permission control receives a transmission path control right transfer signal indicating a transmission path control right to start the transmission permission control, and completes transmission permission control. The transmission line control right transfer signal can be sent to another downstream serial signal transmission line, and the transfer of the transmission line control right transfer signal to the previous downstream hub device is confirmed. A confirmation means for confirming that the transmission path control right is transferred from the side or downstream side to the upstream side hub device,
The terminal sets the transmission path control right transfer signal as a non-signal with a significant time length following the preamble signal of the IEEE 802.3 standard, and a response to the transmission path control right transfer signal sent from one downstream hub device. A data transmission system characterized in that the confirmation is configured as a preamble signal of the standard or a data frame of the standard. At least three hub devices are provided, all of the hub devices have the same configuration, and the hub devices are connected to each other by a serial signal transmission line, and the control of the hub devices is performed by communication on the serial signal transmission line. Each hub device operates according to a protocol, and operates as if it is a single hub device,
A port of each hub device includes a transmission / reception control system in which a plurality of terminals each having a data frame transmission / reception function of IEEE 802.3 standard are connected in a star shape,
The transmission of data frames from the terminal to which one hub apparatus corresponds to each of the hub apparatuses in a predetermined order with respect to the respective ports, and with respect to the terminals connected to the respective hub apparatuses. Means for performing no transmission permission control,
The means for performing the transmission permission control receives a transmission path control right transfer signal indicating a transmission path control right for starting the transmission permission control, and when the transmission permission control is completed, the transmission path control right transfer signal is transmitted to the downstream side. Can be sent to another serial signal transmission line, confirms the transfer of the transmission path control right transfer signal with the previous downstream hub apparatus, and transfers from the upstream side to the downstream side or from the downstream side to the upstream side hub apparatus. Confirmation means for confirming that the transmission path control right has been transferred;
After sending the transmission path control right transfer signal to the downstream serial signal transmission line, the delivery confirmation from the downstream side is monitored for a specified time, and if there is no response to the delivery confirmation, the transmission line control right transfer signal is sent. And means for stopping
The terminal sets the transmission path control right transfer signal as a no-significant time length signal following the IEEE 802.3 preamble signal, and confirms the response of the transmission path control right transfer signal sent from one downstream hub device. Configure as a preamble signal of the standard or a data frame of the standard,
When the hub device stops sending the transmission path control right transfer signal, a situation where there is no transmission path control right temporarily occurs, and then the transmission path control is performed again from the upstream side to the downstream hub apparatus. A data transmission system characterized by transferring rights.   In the data transmission system according to claim 1 or 2, in the hub apparatus that has received the transmission path control right transfer signal, the transmission path control right transfer signal is not relayed to the port of the hub apparatus and the downstream signal transmission path, Instead, an IEEE 802.3 standard preamble signal is sent to the port of the hub device and the upstream and downstream signal transmission paths of the hub device, transmission permission control is started, and an IEEE 802.3 standard data frame from the port is started. Is transmitted to the upstream, downstream, or upstream / downstream instead of the preamble signal, and is not relayed to the port even if the signal is input from the upstream or downstream side.   3. The data transmission system according to claim 1, wherein the hub device having no transmission path control right relays the IEEE 802.3 standard signal sequence received from the upstream or downstream to the reverse signal transmission path, and the IEEE 802. Frame signal of standard 3 is relayed to all ports, and a preamble signal is inserted into each port so that no signal state longer than the frameless signal time defined by the IEEE 802.3 standard does not occur. A data transmission system.

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