JP4152860B2 - COMMUNICATION DEVICE, COMMUNICATION DEVICE, COMPUTER PROGRAM THEREOF, AND RECORDING MEDIUM CONTAINING THE PROGRAM - Google Patents

Description

  The present invention relates to a technique in which a transmission source communication device and a reception destination communication device communicate via a communication device that connects a plurality of communication networks, and in particular, synchronizes clocks between the transmission source communication device and the reception destination communication device. The present invention relates to a communication device, a communication device, a program thereof, and a recording medium on which the program is recorded.

  In recent years, terrestrial digital broadcasting services have attracted attention as new broadcasting services. In this service, high-quality images for home devices such as television and video are stream-transmitted by the MPEG2TS (Moving Picture Experts Group 2 over IP Transfer System) system, and images for mobile devices such as mobile phones are stream-transmitted by the MPEG4 system.

  For example, when MPEG2TS stream data received by a tuner installed in a room in a home is transferred to a television set in another room, how the clock of the tuner on the transmission side advances and the reception side It is desirable that the method of clock advancement of the TV of the same is the same.

  FIG. 20 is a diagram for explaining the influence of the difference between the progress of the clock on the tuner on the transmission side and the progress of the clock on the television on the reception side. In general, when performing stream transmission, a buffer 100 is provided to absorb the influence of data delay and data retransmission caused by an error on the transmission path, and buffering processing is performed. Both the tuner on the transmission side and the television on the reception side perform time management using their own clocks and perform data transmission / reception processing.

  FIG. 20A shows an ideal case where the progress of the clock on the transmission side is exactly the same as the progress of the clock on the reception side. In this case, since the input amount and the output amount with respect to the buffer 100 are the same, the amount of data stored in the buffer 100 is substantially constant, and stable ideal stream transmission is possible.

  On the other hand, FIG. 20B shows a case where the speed of the clock on the transmission side is high and the speed of the clock on the reception side is slow. In this case, since the amount of input to the buffer 100 exceeds the amount of output, the amount of data stored in the buffer 100 increases as time passes, causing an overrun error of the buffer 100.

  FIG. 20C shows a case where the speed of the transmitting side clock is slow and the speed of the receiving side clock is fast. In this case, since the amount of input to the buffer 100 is less than the amount of output, the amount of data stored in the buffer 100 decreases as time passes, causing an underrun error of the buffer 100.

  If an overrun error occurs, the data overflowing from the buffer 100 is lost, causing a problem that the continuity of stream transmission is lost. Also, if an underrun error occurs, data will not reach the sink side, causing a problem of interrupting the stream transmission itself.

  In order to prevent an underrun error or an overrun error of the buffer 100, the flow control is usually used. However, in the case of a terrestrial digital broadcasting service, the flow control cannot be performed on the source side, so these problems are solved. Can not do it. Therefore, as a solution to this problem, it is conceivable to install the same clock progression in both the transmitter tuner and the receiver television. However, since the clock has a certain amount of error, the progress of the clock on the transmission side and the progress of the clock on the reception side do not completely match, and when stream transmission is performed for a long time, FIG. ) Or the problem shown in FIG.

  For example, when an error of a maximum of ± 50 ppm occurs in a clock used in a general AV (Audio Visual) device or the like, when a movie content of 2 hours is transmitted with a high-definition class image quality, a maximum shift of about 0.72 seconds occurs. . If the transfer rate is 24 Mbps, the deviation reaches about 2 Mbytes.

  Therefore, in addition to the memory capacity for absorbing a normal transmission delay, the buffer 100 needs to add a memory capacity of about 2 Mbytes enough to cope with this shift. As described above, it can be easily understood that it is practically difficult to cope with the difference in the degree of advancement of the clock caused by the error of the clock by increasing the capacity of the buffer 100.

  For these reasons, a mechanism for correcting the difference in the degree of clock advance caused by the clock error between the transmission side and the reception side is necessary. In the case of a synchronous communication network, there is a network coordinator called a master or coordinator among the devices participating in the network, and beacons are broadcast at regular intervals to control the timing of transmission and reception. There is a mechanism. When such broadcast communication is performed, it becomes possible for the terminals participating in the network to make corrections to the progress of the clock using the fact that the timing of receiving the broadcast communication is the same. .

  In other words, broadcast communication plays a role of a kind of time signal, and if the terminal that receives it performs correction processing such as resetting the offset value of the clock, the clock shift can be reduced to zero at that moment. . If such broadcast communication is periodically generated, it is possible to prevent the problem of clock deviation accumulation.

  However, this method is only a clock synchronization method that can be achieved only in a single synchronous communication network, and broadcast communication does not reach both sides at the same timing between a plurality of synchronous communication networks. there were. As a clock synchronization technique that can be used even in an environment where a plurality of synchronous communication networks exist, there is an invention disclosed in Japanese Patent No. 3440984 and an invention disclosed in Japanese Patent Publication No. 6-56998.

  Japanese Patent No. 3440984 discloses an information processing apparatus that can establish synchronization of broadcast communication between different environments. According to this prior art, when performing synchronous communication between the wired environment and the wireless environment, the time information related to the synchronization in the wired environment can be reflected in the time information related to the synchronization in the wireless environment. It becomes possible to maintain consistency.

Japanese Examined Patent Publication No. 6-56998 includes a first digital station, and the first digital station is connected to the second digital network via an integrated service digital network (ISDN), an interworking unit, and a public exchange analog network. In a data transmission system in data communication with a data station, a method for synchronizing the local clock of each data station is disclosed. This prior art makes it possible to synchronize a digital data transmission device controlled by a central clock source in a digital network and synchronized with a central clock in the digital network with a clock external to the network.
Japanese Patent No. 3440984 Japanese Examined Patent Publication No. 6-56998

  When synchronizing a source communication device and a destination communication device communicated via a plurality of synchronous communication networks, it is necessary to synchronize the network clock of the synchronous communication network and the local clock of the communication device in the middle of the route. Such a method is not preferable. However, the information processing apparatus disclosed in Japanese Patent No. 3440984 has a problem that network synchronization of different communication networks must be performed.

  FIG. 21 is a diagram for explaining problems in performing network synchronization of different communication networks. In FIG. 21A, communication device A 101 and communication device B 102 communicate via three different synchronous communication networks, and similarly communication device C 103 and communication device D 104 pass through three different synchronous communication networks. The relationship of the network clock during communication is shown. Communication devices A101 to D104 indicate devices corresponding to a transmission source or a reception destination when performing data transmission. Communication devices 1 to 4 (111 to 114) indicate devices that play a role of bridging different synchronous communication networks.

  Originally, a synchronous communication network operates with its own network clock, and therefore there is no synchronization timing consistency between different synchronous communication networks. In the above-described prior art, a communication apparatus that connects different synchronous communication networks compares each network clock, and uses one of the comparison results to match one network clock with the other network clock. By using this technique, the communication device 1 (111) shown in FIG. 21A is configured so that the network clock between the communication device A101 and the communication device 1 (111), the communication device 1 (111), and the communication device 2 are used. The network clock between the communication device 1 (111) and the communication device 2 (112) is compared with the network clock between the communication device A101 and the communication device 1 (111). Can be set to the network clock.

  The network clock between the communication device A 101 and the communication device 1 (111) is “main”, and the network clock between the communication device 1 (111) and the communication device 2 (112) is “subordinate”. This can be seen as a master-slave relationship with the network clock. The network clock between the communication device 1 (111) and the communication device 2 (112) and the network clock between the communication device 2 (112) and the communication device B102 can similarly form a master-slave relationship.

  As a result, the three different synchronous communication networks between the communication device A101 and the communication device B102 are unified with the synchronization timing based on the network clock between the communication device A101 and the communication device 1 (111). Therefore, it is possible to smoothly perform stream transmission between the communication device A101 and the communication device B102.

  If the communication device C103 and the communication device D104 are considered in the same manner, the communication between the three different synchronous communication networks between the communication device C103 and the communication device D104 is established by forming a master-slave relationship of the network clock. Since the synchronization timing can be unified based on the network clock between the device C103 and the communication device 3 (113), it is possible to smoothly perform stream transmission between the communication device C103 and the communication device D104. Become.

  In this state, the communication device A101-communication device 1 (111) -communication device 2 (112) -communication device 4 (114) -communication device D104 is used between the communication device A101 and the communication device D104. Consider performing stream transmission. As described above, when the master-slave relationship of the network clock is formed, the synchronous communication network between the communication device 2 (112) and the communication device 4 (114) as shown in FIG. There is a problem that it is not clear which one of the network clock between the communication device A101 and the communication device 1 (111) and the network clock between the communication device C103 and the communication device 3 (113) is set.

  Moreover, the synchronous communication network between the communication device 2 (112) and the communication device 4 (114) is set to the synchronization timing based on the network clock between the communication device A101 and the communication device 1 (111). However, since the synchronization timing based on the network clock between the communication device 4 (114) and the communication device D104 is different, the stream transmission between the communication device A101 and the communication device D104 cannot be performed well. There is a point.

  Conversely, the synchronous communication network between the communication device 2 (112) and the communication device 4 (114) is matched with the synchronization timing based on the network clock between the communication device C103 and the communication device 3 (113). However, since the synchronization timing based on the network clock between the communication device A101-communication device 1 (111) -communication device 2 (112) is different, the stream between the communication device A101 and the communication device D104 is also used. There is a problem that transmission cannot be performed well.

  In order to avoid this problem, as shown in FIG. 21 (c), the synchronous communication network between the communication device 2 (112) and the communication device 4 (114) is changed to the communication device A101 and the communication device 1 (111). The network clock between the communication device C103-communication device 3 (113) -communication device 4 (114) -communication device D104 also matches the communication device A101. And a synchronization timing based on a network clock between the communication device 1 (111) and the communication device 1 (111) can be considered.

  However, according to this method, during the process of changing the synchronization timing between the communication device C103-communication device 3 (113) -communication device 4 (114) -communication device D104, There is a problem that stream transmission with the communication device D104 cannot be performed well.

  Another problem with this method is that a plurality of independent synchronous communication networks cannot be handled. An independent synchronous communication network is a network having the property that the synchronization timing of the network cannot be adjusted to that of other synchronous communication networks, and a public line network or the like corresponds to this. When an independent synchronous communication network is connected to a non-independent synchronous communication network to achieve synchronization timing consistency, the independent synchronous communication network cannot be synchronized with the synchronization timing of other synchronous communication networks. As for the master-slave relationship of synchronization, it is necessary to form a relationship in which an independent synchronous communication network is “main” and a non-independent synchronous communication network is “subordinate”.

  Under these restrictions, if the synchronization timing consistency of different synchronous communication networks is to be solved by the network synchronization technique, if there are two or more independent synchronous communication networks on the transmission path, the transmission path Since the synchronization timings of the above different synchronous communication networks cannot be unified, there is a problem that stream transmission cannot be performed successfully.

  In the digital data transmission system disclosed in the above-mentioned Japanese Patent Publication No. 6-56998, there is a problem that the synchronization timing cannot be adjusted on a transmission path passing through three or more synchronous communication networks. This problem will be described below.

  The interworking unit that plays the role of connecting the integrated service digital network and the public analog network compares the network clock of the integrated service digital network with the local clock of the data station adjacent to the public analog network, and compares the comparison results with the integrated service. Transfer to a digital station connected to the digital network.

  The digital station matches the synchronization timing by generating the local clock of the digital station synchronized with the synchronization timing of the local clock of the data station from the network clock of the general service digital network and the comparison result. In this prior art, it is assumed that the system is established in an environment composed of two synchronous communication networks, a general service digital network and a public analog network.

  Here, let us consider a case in which this prior art is expanded to assume a transmission path passing through three or more synchronous communication networks. The local clock of the first data station is compared with the clock of the synchronous network opposite to the first data station as viewed from the interoperating unit, and the comparison result is sent to the second data station. If the second data station local clock is synchronized with the first data station local clock in the same procedure, the first data station and the nth data station can be synchronized. It will be.

  However, all local clocks of data stations in the meantime are subject to synchronization restrictions. Furthermore, since a master-slave relationship can be established between data stations, there is a restriction that a data station in the middle of two transmission paths must abandon synchronization of either transmission path.

  That is, the invention disclosed in Japanese Patent No. 3440984 requires synchronization between network clocks in the middle, and the invention disclosed in Japanese Patent Publication No. 6-56998 has all the local clocks of the device through which data passes. Restricted to synchronize. In any of the conventional techniques, only the synchronization between the upper layer of the transmission source and the upper layer of the reception destination without restricting the relationship between the network clock of the network between the transmission source communication device and the reception destination communication device and the local clock of the communication device. It has the problem that it cannot be taken.

  The present invention has been made to solve the above-described problems, and a first object is to provide time information in a higher layer of a transmission source communication device and a reception destination without matching synchronization timing in a synchronous communication network. To provide a communication device capable of synchronizing time information in an upper layer of a communication device, a transmission source communication device, a reception destination communication device, a computer program thereof, and a recording medium recording the program.

  According to an aspect of the present invention, a communication device is a communication device on a transmission path in which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. Comparing means for comparing time information generated from synchronization signals of a plurality of connected communication networks, receiving means for receiving a frame from the communication network on the transmission side, and a frame received by the receiving means A comparison value obtained by the comparison means and an addition means for adding comparison information including identification information for identifying a communication device corresponding to the comparison value; and a frame to which the comparison information is added by the addition means. Transmitting means for transmitting to the receiving communication device. A frame is a processing unit of information handled by a protocol including data information, control information, and the like. In particular, a frame in the present invention has a fixed length of comparison information of a source communication device and comparison information of a plurality of communication devices. Or a field for storing the comparison information of the transmission source communication device and the comparison information of the plurality of communication devices in a variable length form sequentially connected. In what field structure the frame is handled is predetermined. In many cases, the same frame is used through a plurality of networks, but a frame composed of different fields may be used. When different frames are used, it is possible to identify the frame configuration and to convert the frame between the transmission source and the reception destination, or to receive and use the communication device or communication device of the transmission source upper control layer. The control means for matching the time information with the time information of the higher layer of the receiving communication device includes a function of adjusting the comparison information from the transmission source to the receiving destination according to the identification result of the frame and performing control. .

  According to still another aspect of the present invention, a communication device is provided on a transmission path in which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. Comparing means for comparing time information generated from synchronization signals of a plurality of connected communication networks, receiving means for receiving a frame from a communication network on a transmission source side, and receiving means received by a receiving means. A storage means for calculating a cumulative comparison value included in the frame and a comparison value obtained by the comparison means, and storing the calculated comparison value in the frame as a new cumulative comparison value; and a frame in which the cumulative comparison value is stored by the storage means For transmitting to the receiving communication device. The cumulative comparison value is generated by performing a predetermined calculation between the comparison value sent from another device and the comparison value of the own device, and received from another device as a new comparison value. Replace with the comparison value. If the cumulative comparison value is used, the comparison value field does not increase regardless of the number of communication apparatuses on the transmission path.

  According to yet another aspect of the present invention, a transmission source communication device is a transmission path through which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. Comparing means for comparing the time information generated from the synchronization signal of the connected communication network with the time information of the upper control layer, the comparison value obtained by the comparing means, Generation means for generating a frame including comparison information including identification information for specifying a transmission source communication device, and transmission means for transmitting the frame generated by the generation means to a reception destination communication device Including.

  Preferably, the frame includes a field for storing comparison information of a transmission source communication device and comparison information of a plurality of communication devices.

  According to still another aspect of the present invention, the destination communication device is a transmission path through which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. A comparison value between the time information generated from the synchronization signal of the communication network to which the transmission source communication device is connected and the time information of the upper control layer of the transmission source communication device, and the communication device A receiving means for receiving a comparison value of time information generated from synchronization signals of a plurality of connected communication networks, and a comparison value of a transmission source communication device and a comparison value of a communication apparatus received by the receiving means And control means for matching the time information of the upper control layer of the source communication device with the time information of the upper layer of the destination communication device.

  According to still another aspect of the present invention, a computer program is transmitted on a transmission path through which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. A computer program for causing a computer to execute a communication method of a communication apparatus in the communication method, the communication method comprising: comparing time information generated from synchronization signals of a plurality of connected communication networks; A step of receiving a frame from the network, a step of adding comparison information including identification information for identifying a communication device corresponding to the obtained comparison value and the comparison value to the received frame, and comparison information is added Transmitting the received frame to the destination communication device.

  According to still another aspect of the present invention, a computer program is transmitted on a transmission path through which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. Is a computer program for causing a computer to execute a communication method of a transmission source communication device in the communication method, and the communication method compares time information generated from a synchronization signal of a connected communication network with time information of a higher control layer Generating a frame including comparison information including the obtained comparison value and identification information for identifying the transmission source communication device, and transmitting the generated frame to the receiving communication device. including.

According to still another aspect of the present invention, a computer program is transmitted on a transmission path through which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. Is a computer program for causing a computer to execute a communication method of a destination communication device in the communication method, the communication method including time information generated from a synchronization signal of a communication network to which the transmission source communication device is connected, and the transmission source communication device Receiving the comparison value with the time information of the upper control layer of the communication device and the comparison value of the time information generated from the synchronization signals of a plurality of communication networks to which the communication device is connected, and Matching the time information of the upper control layer of the transmission source communication device and the time information of the upper layer of the destination communication device based on the comparison value and the comparison value of the communication device.

  According to yet another aspect of the present invention, a computer-readable recording medium is a communication medium in which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. A computer-readable recording medium storing a program for causing a computer to execute a communication method of a communication device on a transmission path to be performed, the communication method being generated from a synchronization signal of a plurality of connected communication networks A step of comparing information, a step of receiving a frame from the communication network on the transmission side, and a received frame including the obtained comparison value and identification information for identifying a communication device corresponding to the comparison value A step of adding the comparison information, and a step of transmitting the frame to which the comparison information is added to the receiving communication device.

  According to yet another aspect of the present invention, a computer-readable recording medium is a communication medium in which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. A computer-readable recording medium recording a program for causing a computer to execute a communication method of a transmission source communication device on a transmission path to be performed, the communication method being time generated from a synchronization signal of a connected communication network A step of comparing the information with time information of the upper control layer, and a step of generating a frame including comparison information including the obtained comparison value and identification information for identifying the transmission source communication device. Transmitting the received frame to the destination communication device.

According to yet another aspect of the present invention, a computer-readable recording medium is a communication medium in which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. A computer-readable recording medium recording a program for causing a computer to execute a communication method of a destination communication device on a transmission path to be performed, the communication method being synchronized with a communication network to which a transmission source communication device is connected Receives a comparison value between the time information generated from the signal and the time information of the upper control layer of the transmission source communication device, and a comparison value of the time information generated from the synchronization signals of multiple communication networks to which the communication device is connected And the time information of the upper control layer of the source communication device and the time information of the upper layer of the destination communication device based on the received comparison value of the transmission source communication device and the comparison value of the communication device. The comprises the step of aligning.

  According to an aspect of the present invention, the comparison unit includes the comparison value obtained by the comparison unit obtained by the comparison unit and the identification information for identifying the communication device corresponding to the comparison value in the frame received by the reception unit. And the transmission means transmits the frame to which the comparison information has been added by the addition means to the reception destination communication device, so that the reception destination communication device has the time information in the higher layer of the transmission source communication device, and the reception destination communication device. It becomes possible to obtain comparison information of communication devices that are necessary when synchronizing with time information in the upper layer.

  According to another aspect of the present invention, the comparison unit compares the time information generated from the synchronization signal of the connected communication network with the time information of the higher control layer, and the generation unit is obtained by the comparison unit. Since the transmission unit generates the frame including the comparison information including the comparison value and the identification information for specifying the transmission source communication device, and the transmission unit transmits the frame generated by the generation unit to the reception destination communication device. It becomes possible for the communication device to acquire comparison information of the transmission source communication device required when synchronizing the time information in the upper layer of the transmission source communication device and the time information in the upper layer of the reception destination communication device. It was.

  According to still another aspect of the present invention, the control means uses the comparison value of the transmission source communication apparatus and the comparison value of the communication apparatus received by the reception means, and the time information of the upper control layer of the transmission source communication apparatus And the time information in the upper layer of the destination communication device, so that the time information in the upper layer of the source communication device and the time in the upper layer of the destination communication device are matched without matching the synchronization timing in the synchronous communication network. It became possible to synchronize information.

(First embodiment)
FIG. 1 is a block diagram showing a schematic configuration of a transmission path in the first embodiment of the present invention. This transmission path includes communication devices 1a and 1b, a transmission source communication device 2, a reception destination communication device 3, and first to third synchronous communication networks 4 to 6. The transmission source communication device 2 is connected to the first synchronous communication network 4 and transmits data to the reception destination communication device 3 via the communication devices 1a and 1b.

  In addition, the communication device 1 a connects the first synchronous communication network 4 and the second synchronous communication network 5, and the communication device 1 b connects the second synchronous communication network 5 and the third synchronous communication network 6. The destination communication device 3 is connected to the third synchronous communication network 6 and receives data from the transmission source communication device 2 via the communication devices 1a and 1b. Details of the communication devices 1a and 1b, the transmission source communication device 2, and the reception destination communication device 3 will be described later. In the following description, the communication devices 1a and 1b are collectively referred to as the communication device 1.

  FIG. 2 is a diagram illustrating an external appearance example of the communication device 1 according to the first embodiment of the present invention. The communication device 1 is equipped with a computer main body 71, a display device 72, an FD drive 73 to which an FD (Flexible Disk) 74 is attached, a keyboard 75, a mouse 76, and a CD-ROM (Compact Disc-Read Only Memory) 78. A CD-ROM device 77 and a network communication device 79 are included. A program for realizing the function of the communication device 1 (hereinafter referred to as a communication program) is supplied by a recording medium such as the FD 74 or the CD-ROM 78. When the communication program is executed by the computer main body 71, communication described later is performed. The communication program may be supplied to the computer main body 71 from another computer via the communication line and the network communication device 79. Note that the external appearances of transmission source communication device 2 and reception destination communication device 3 are also the same, and therefore detailed description will not be repeated.

  The recording medium is not limited to the FD 74 or the CD-ROM 78, but may be a magnetic tape, MO (Magnetic Optical disk), MD (Mini Disc), DVD (Digital Versatile Disc), IC (Integrated Circuit) card, or the like. May be.

  FIG. 3 is a block diagram illustrating a configuration example of the communication device 1 according to the first embodiment of the present invention. A computer main body 71 shown in FIG. 2 includes a central processing unit (CPU) 80, a read only memory (ROM) 81, a random access memory (RAM) 82, and a hard disk 83. The CPU 80 performs processing while inputting / outputting data to / from the display device 72, the FD drive 73, the keyboard 75, the mouse 76, the CD-ROM device 77, the network communication device 79, the ROM 81, the RAM 82, or the hard disk 83. The communication program recorded in the FD 74 or the CD-ROM 78 is stored in the hard disk 83 by the CPU 80 via the FD drive 73 or the CD-ROM device 77. The CPU 80 loads the communication program from the hard disk 83 to the RAM 82 as appropriate, and executes the communication program, which will be described later. The configurations of transmission source communication device 2 and reception destination communication device 3 are also the same, and thus detailed description will not be repeated.

  FIG. 4 is a block diagram showing a functional configuration of the communication apparatus 1 according to the first embodiment of the present invention. The communication device 1 is configured by a lower communication layer that is often implemented mainly as hardware and an upper control layer that is often implemented mainly as software or firmware. In the following description, the first lower communication layer is a side that receives data viewed from the communication device 1, and the second lower communication layer is a side that transmits data viewed from the communication device 1.

  The upper control layer of the communication device 1 includes a frame processing unit 11, an identification information storage unit 12, and a comparison processing unit 13. The first lower communication layer includes a first communication management unit 14 and a first time management unit 15. Further, the second lower communication layer includes a second communication management unit 16 and a second time management unit 17.

  The frame processing unit 11 analyzes the contents of the data received by the first communication management unit 14, reconstructs the frame as necessary, and causes the second communication management unit 16 to send the data. When the frame processing unit 11 reconstructs a frame, information necessary for the reconstruction is acquired from the comparison processing unit 13 or the identification information storage unit 12 as necessary.

  The identification information storage unit 12 stores identification information for specifying the communication device 1. Then, in accordance with a request from the frame processing unit 11, the stored identification information is notified to the frame processing unit 11. This identification information is mainly used for the destination communication device 3 to identify the communication device 1.

  The comparison processing unit 13 includes a time management table and a comparison value calculation table, which will be described later, acquires time information from the first time management unit 15 and the second time management unit 17 and stores the time information in the time management table. Further, in accordance with a request from the frame processing unit 11, the comparison value is calculated using the comparison value calculation table based on the time information stored in the time management table, and the comparison value as the calculation result is calculated. Notify

  The first communication management unit 14 performs communication processing with respect to the synchronous communication network that is in contact with the communication device 1 and that receives data for the communication device 1. In the following description, the synchronous communication network in which the first communication management unit 14 performs communication processing is referred to as the first synchronous communication network 4. When the first communication management unit 14 receives data from the first synchronous communication network 4, it passes the received data to the frame processing unit 11. In addition, when information related to the synchronization timing of the first synchronous communication network 4 is received from the first synchronous communication network 4, the information is notified to the first time management unit 15.

  The first time management unit 15 manages time information based on the synchronization timing of the first synchronous communication network 4, and notifies the comparison processing unit 13 of the time information according to a request from the comparison processing unit 13. Further, the time information is adjusted based on the information related to the synchronization timing of the first synchronous communication network 4 obtained from the first communication management unit 14.

  The second communication management unit 16 performs communication processing with respect to the synchronous communication network that is in contact with the communication device 1 and that transmits to the communication device 1. In the following description, the synchronous communication network in which the second communication management unit 16 performs communication processing is referred to as the second synchronous communication network 5. When receiving data from the frame processing unit 11, the second communication management unit 16 sends the data to the second synchronous communication network 5. In addition, when information related to the synchronization timing of the second synchronous communication network 5 is received from the second synchronous communication network 5, the information is notified to the second time management unit 17.

  The second time management unit 17 manages time information based on the synchronization timing of the second synchronous communication network 5 and notifies the comparison processing unit 13 of the time information in accordance with a request from the comparison processing unit 13. Further, the time information is adjusted based on the information related to the synchronization timing of the second synchronous communication network 5 obtained from the second communication management unit 16.

  FIG. 5 is a block diagram illustrating a functional configuration of the transmission source communication device 2 according to the first embodiment of the present invention. The transmission source communication device 2 includes a lower communication layer that is mainly implemented as hardware and an upper control layer that is mainly implemented as software or firmware. The upper control layer of the transmission source communication device 2 includes a data processing unit 21, an upper control layer time management unit 22, a frame construction unit 23, a comparison processing unit 24, and an identification information storage unit 25. The lower communication layer includes a communication management unit 26 and a lower communication layer time management unit 27.

  The data processing unit 21 gives a time stamp to data to be transmitted to the receiving communication device 3. The data processing unit 21 acquires time information from the upper control layer time management unit 22 when assigning a time stamp. In addition, the data processing unit 21 gives the data with the time stamp to the frame construction unit 23.

  The upper control layer time management unit 22 has a free-running clock, and generates time information using this free-running clock. In addition, the upper control layer time management unit 22 provides time information to the data processing unit 21 in response to a request from the data processing unit 21. Further, time information is given to the comparison processing unit 24 in response to a request from the comparison processing unit 24.

  The frame construction unit 23 transmits a frame with a time stamp received from the data processing unit 21 to the first synchronous communication network 4 with which the transmission source communication device 2 is connected, in accordance with the protocol specifications of the first synchronous communication network 4. Process. Further, the frame construction unit 23 acquires the comparison value information from the comparison processing unit 24 and the identification information from the identification information storage unit 25 as necessary when performing the framing process, and stores these information in the frame. Process to store. The frame construction unit 23 sends the data subjected to the framing process to the communication management unit 26.

  The comparison processing unit 24 includes a time management table and a comparison value calculation table, which will be described later, acquires time information from the upper control layer time management unit 22 and the lower communication layer time information management unit 27 and stores the time information in the time management table. . The comparison processing unit 24 calculates a comparison value using a comparison value calculation table based on the time information stored in the time management table in accordance with a request from the frame construction unit 23, and compares the comparison result. The value is notified to the frame construction unit 23.

  The identification information storage unit 25 stores identification information for specifying the transmission source communication device 2. The identification information storage unit 25 notifies the frame construction unit 23 of the stored identification information in accordance with a request from the frame construction unit 23. This identification information is mainly used for the destination communication device 3 to identify the transmission source communication device 2.

  The communication management unit 26 performs communication processing on the first synchronous communication network 4 with which the transmission source communication device 2 is in contact. The communication processing at this time conforms to the protocol specification adopted in the synchronous communication network. In addition, when the communication management unit 26 receives a data frame from the frame construction unit 23, the communication management unit 26 transmits the data frame to the first synchronous communication network 4. Further, when the communication management unit 26 receives information related to the synchronization timing of the synchronous communication network from the first synchronous communication network 4, the communication management unit 26 notifies the lower communication layer time management unit 27 of the information.

  The lower communication layer time management unit 27 manages time information based on the synchronization timing of the first synchronous communication network 4 with which the transmission source communication device 2 is in contact, and notifies the comparison processing unit 24 of the time information in accordance with a request from the comparison processing unit 24. To do. Further, the lower communication layer time management unit 27 adjusts the time information based on the information regarding the synchronization timing of the first synchronous communication network 4 obtained from the communication management unit 26.

  FIG. 6 is a block diagram showing a functional configuration of the destination communication device 3 according to the first embodiment of the present invention. This destination communication device is mainly composed of a lower communication layer that is often implemented as hardware and an upper control layer that is mainly implemented as software or firmware. The upper control layer includes a data processing unit 31, an upper control layer time management unit 32, a frame analysis unit 33, and a comparison processing unit 34. The lower communication layer includes a communication management unit 35 and a lower communication layer time management unit 36.

  The data processing unit 31 processes the received data based on the time stamp given to the received data. Note that the timing at which the data processing unit 31 processes the received data is determined by collating the correction time information acquired from the upper control layer time management unit 32 with the time stamp given to the received data. Received data is supplied from the frame analysis unit 33.

  The upper control layer time management unit 32 has a free-running clock, generates time information from the free-running clock, and generates corrected time information using the total comparison value obtained from the comparison processing unit 34. Further, the upper control layer time management unit 32 provides the correction time information to the data processing unit 31 in response to a request from the data processing unit 31. In addition, the upper control layer time management unit 32 provides time information to the comparison processing unit 34 in response to a request from the comparison processing unit 34.

  The frame analysis unit 33 performs frame analysis processing on the received frame received from the communication management unit 35 in accordance with the protocol specification of the synchronous communication network with which the destination communication device 3 is in contact. The frame analysis unit 33 gives the data processing unit the received data to which the time stamp obtained by the frame analysis process is added. Further, the frame analysis unit 33 gives comparison information obtained by the frame analysis processing to the comparison processing unit 34.

  The comparison processing unit 34 includes a time management table, a comparison value calculation table, and a comparison value table, which will be described later, and acquires time information from the upper control layer time management unit 32 and the lower communication layer time information management unit 36 to perform time management. Store in the table. Further, the comparison processing unit 34 stores the comparison information received from the frame analysis unit 33 in the comparison value table. Further, the comparison processing unit 34 calculates a comparison value using a comparison value calculation table based on the time information stored in the time management table, and compares the comparison value as a calculation result with the destination communication device 3. Stored in the comparison value table as a value. In addition, the comparison processing unit 34 calculates a total comparison value from the comparison values stored in the comparison value table, and notifies the higher control layer time management unit 32 of the total comparison value.

  The communication management unit 35 performs communication processing with respect to the third synchronous communication network 6 with which the destination communication device 3 is in contact. The communication process at this time conforms to the protocol specification adopted in the third synchronous communication network 6. The communication management unit 35 gives the data frame to the frame analysis unit 33 when receiving the data frame from the third synchronous communication network 6. When the communication management unit 35 receives information related to the synchronization timing of the synchronous communication network from the third synchronous communication network 6, the communication management unit 35 notifies the lower communication layer time management unit 36 of the information.

  The lower communication layer time management unit 36 manages time information based on the synchronization timing of the third synchronous communication network 6 with which the destination communication device 3 is in contact, and notifies the comparison processing unit 34 of the time information in accordance with a request from the comparison processing unit 34. To do. Further, the time information is adjusted based on the information related to the synchronization timing of the third synchronous communication network 6 obtained from the communication management unit 35.

  7 to 9 show that the transmission source communication device 2 and the destination communication device 3 are connected to each other by transmitting basic type comparison information to the destination communication device 3 in the transmission path according to the first embodiment of the present invention. It is a flowchart for demonstrating the process sequence to synchronize.

  FIG. 7 is a flowchart for explaining the processing procedure of the transmission source communication device 2 according to the first embodiment of the present invention. First, the data processing unit 21 determines whether there is data to be transmitted to the receiving communication device 3 (S11). If there is no data to be transmitted (S11, No), the process of step S11 is repeated.

  If there is data to be transmitted (S11, Yes), the data processing unit 21 obtains time information from the upper control layer time management unit 22 (S12), assigns the information to the data to be transmitted as a time stamp, The data is sent to the construction unit 23 (S13). When receiving the data with the time stamp, the frame construction unit 23 determines whether or not to acquire a comparison value (S14). If the comparison value is not acquired (S14, No), the process proceeds to step S17.

  When the comparison value is acquired (S14, Yes), the comparison value is acquired from the comparison processing unit 24 (S15), and the identification information is acquired from the identification information storage unit 25 (S16). Note that the comparison value acquisition determination indicates that it is determined whether or not to store a comparison value when valid data is not yet stored in the field storing the comparison value in the frame.

  When handling basic comparison information, if you want to send comparison information at regular intervals, an acquisition counter is prepared, and the acquisition counter is incremented every time framing processing is performed, and when the counter reaches a certain number A method for obtaining a comparison value is conceivable. For example, if the fixed number is set to 10, every time the framing process is performed 10 times, the process of acquiring the comparison value is performed once.

  In addition, when the comparison information transmission interval is not constant, a random number is generated when a framing process is performed using a random number generator, and a comparison value is obtained when the random value falls below a specific value. Possible ways to do this. For example, if the unique value is set to 15 and a random number is generated between 0 and 99, when the framing process is performed, the process of acquiring the comparison value with a probability of 15% is performed together. Become.

  Next, the frame construction unit 23 performs framing processing based on the protocol specification adopted by the first synchronous communication network 4 with which the transmission source communication device 2 is in contact with the data with the time stamp (S17). When the comparison value acquisition process is performed, basic type comparison information generated from the acquired comparison value information and the identification information is framed together during the framing process.

  FIG. 10A shows an example of basic type comparison information. The basic type comparison information includes device identification information for specifying the transmission source communication device 2 and comparison value information.

  FIG. 11A is a diagram illustrating an example of a data frame generated by the frame construction unit 23. This data frame includes a data identifier, a destination address, a transmission source address, a time stamp, a data length, a data storage area, and a comparison information field.

  The data identifier indicates that this frame is a data frame. The receiving destination address indicates address information for specifying the receiving destination communication device 3, and for example, an IP (Internet Protocol) address or a MAC (Media Access Control) address of the receiving destination communication device 3 is used. The transmission source address indicates address information for specifying the transmission source communication device 2, and for example, the IP address or the MAC address of the transmission source communication device 2 is used.

  FIG. 12A shows a comparison information format stored in the comparison information field. The comparison information format includes a format type, address information of a destination communication device, address information of a transmission source communication device, and comparison information contents.

  FIG. 12B is a diagram illustrating a table for explaining the format type. In the case of the data frame shown in FIG. 11A, since the address information is already stored, the address information field in the comparison information format can be omitted. Further, since the basic type comparison information is stored in the comparison information content, the format type of the data frame shown in FIG. 12A is “00000001”.

  As a result, the configuration of the frame generated by the frame construction unit 23 is as shown in FIG. If the frame construction unit 23 has not acquired the comparison value, the field for storing the basic type comparison information is filled with zero to indicate that the basic type comparison information is not stored.

  Next, the frame construction unit 23 gives the generated data frame to the communication management unit 26 (S18). The communication management unit 26 transmits the received data frame to the first synchronous communication network 4 with which the transmission source communication device 2 is in contact (S19), returns to step S11, and repeats the subsequent processing.

  FIG. 8 is a flowchart for explaining the processing procedure of the communication apparatus 1 according to the first embodiment of the present invention. First, the first communication management unit 14 determines whether or not a data frame has been received (S21). If no data frame has been received (S21, No), the process of step S21 is repeated.

  When the first communication management unit 14 receives the data frame (S21, Yes), it sends the received data frame to the frame processing unit 11 (S22). The frame processing unit 11 performs frame analysis on the data frame received from the first communication management unit 14 based on the protocol specifications adopted by the first synchronous communication network 4 (S23). If the comparison information is stored in the data frame (S24, No), the process proceeds to step S28.

  If comparison information is not stored in the data frame (S24, Yes), the frame processing unit 11 determines whether or not to acquire a comparison value (S25). Note that the method of using the acquisition counter or the random number generator described in the processing of the frame construction unit 23 of the transmission source communication device 2 can be considered for the determination of the acquisition of the comparison value. If the comparison value is not acquired (S25, No), the process proceeds to step S28.

  When acquiring the comparison value (S25, Yes), the frame processing unit 11 acquires the information of the comparison value from the comparison processing unit 13 (S26), and further acquires the identification information from the identification information storage unit 12 ( S27). Next, the frame processing unit 11 reconstructs the frame based on the protocol specification adopted by the second synchronous communication network 5 based on the analysis result of the frame (S28). When the comparison value acquisition process is performed, the basic type comparison information generated from the acquired comparison value information and the identification information is framed at the time of frame reconstruction. The method of framing the basic comparison information together is the same as that described in the processing of the frame construction unit 23 of the transmission source communication device 2.

  Next, the frame processing unit 11 sends the reconstructed data frame to the second communication management unit 16 (S29). The second communication management unit 16 sends the data frame received from the frame processing unit 11 to the second synchronous communication network 5 (S30), returns to step S21, and repeats the subsequent processing.

  FIG. 9 is a flowchart for explaining the processing procedure of the receiving communication apparatus 3 according to the first embodiment of the present invention. First, the communication manager 35 determines whether a data frame has been received (S31). If no data frame has been received (S31, No), the process of step S31 is repeated.

  When the data frame is received (S31, Yes), the communication management unit 35 sends the received data frame to the frame analysis unit 33 (S32). The frame analysis unit 33 performs frame analysis on the received data frame based on the protocol specification adopted by the third synchronous communication network 6 with which the destination communication device 3 is in contact (S33). If the comparison information is not stored in the data frame (S34, No), the process proceeds to step S36.

  If comparison information is stored in the data frame (S34, Yes), the comparison information is sent to the comparison processing unit 34 (S35). Then, the frame analysis unit 33 extracts data with a time stamp from the data frame and sends it to the data processing unit 31 (S36).

  The data processing unit 31 stores the data with the time stamp in the jitter absorption buffer until the timing for processing the data with the time stamp comes (S37), returns to step S31, and repeats the subsequent processing. .

  The data shown in FIG. 7 to FIG. 9 is transmitted from the transmission source communication device 2 to the reception destination communication device 3.

  Next, a method for obtaining a comparison value in the first embodiment of the present invention will be described. In addition, although the process which calculates | requires a comparison value is performed in each comparison process part 13, 24, and 34 of the transmission origin communication apparatus 2, the communication apparatus 1, and the receiving destination communication apparatus 3, only the object which calculates | requires a comparison value differs, and the calculation method Since these are the same, the communication device 1 will be described as a representative.

  FIG. 13 is a flowchart for explaining a processing procedure for storing time information necessary for calculating the comparison value in the time management table. The comparison processing unit 13 has a time information acquisition flag, and determines whether or not this time information acquisition flag is ON (S41). If the time information acquisition flag is not ON (S41, No), the process proceeds to step S45. When the time information acquisition flag is ON (S41, Yes), the comparison processing unit 13 acquires time information from the first time management unit 15 and the second time management unit 17 (S42).

  FIG. 14A is a diagram illustrating an example of the time management table of the communication device 1. This time management table shows a case where the comparison processing unit 13 acquires time information from the first time management unit 15 and the second time management unit 17 every 50 ms.

  FIG. 14B is a diagram illustrating an example of a time management table of the transmission source communication device 2 or the reception destination communication device 3. This time management table shows a case where the comparison processing unit 24 or 34 acquires time information from the upper control layer time management unit 22 or 32 and the lower communication layer time management unit 27 or 36 every 50 ms.

  Next, the comparison processing unit 13 registers the acquired time information in the time management table (S43), and turns off the time information acquisition flag (S44). Then, the comparison processing unit 13 checks the time counter (S45), turns on the time information acquisition flag when the elapsed time exceeds 50 ms (S46), and resets the time counter to zero (S47). Then, the process returns to step S41 and the subsequent processing is repeated.

  With the above processing, it is possible to perform the time information acquisition operation at a constant interval of about 50 ms. The time counter method is merely an example, and it is not always necessary to acquire time information at regular intervals. For example, the time information acquisition flag is turned on when a request for a comparison value is made from the frame processing unit 11. Also good.

  FIG. 14C is a diagram illustrating an example of a comparison value calculation table. The comparison value calculation table includes a change amount of time information of the first time management unit 15, a change amount of time information of the second time management unit 17, a change amount of time information of the first time management unit 15, 2 and the ratio with the change amount of the time information of the time management unit 17. The comparison processing unit 13 calculates a change amount of the time information in each observation section from the time information stored in the time management table, obtains a ratio of the change amounts, and stores it in the comparison value calculation table.

  The comparison value can be obtained by taking the average value of the ratios of changes in each observation section. Alternatively, a method may be used in which a comparison value is obtained by taking an average value from the remaining 80% ratio excluding 10% of the large value ratio and 10% of the small value ratio in each observation section. By doing this, even if there is a section where normal time information cannot be observed in the case where the terminal managing the synchronization timing of the synchronous communication network changes, the information can be removed. It is possible to obtain an accurate comparison value.

  FIG. 15 is a diagram for describing processing for generating a total comparison value of transmission paths according to the first embodiment of this invention. FIG. 15A is a diagram illustrating identification information and calculated comparison values of the transmission source communication device 2, the communication devices 1a, 1b, and 1c, and the reception destination communication device 3.

  FIG. 15B is a diagram illustrating a comparison value table included in the destination communication device 3. When receiving the comparison information received from the transmission source communication device 2 and the communication devices 1a, 1b, and 1c from the frame analysis unit 33 of the reception destination communication device 3, the comparison processing unit 34 of the reception destination communication device 3 identifies the comparison value. Information is stored in the comparison value table. Further, the comparison processing unit 34 of the reception destination communication device 3 also stores comparison information of the reception destination communication device 3 itself. In the case of the transmission path shown in FIG. 15A, the comparison value table shown in FIG. 15B is created.

  FIG. 16 is a flowchart for explaining a processing procedure when the comparison processing unit 34 of the destination communication device 3 calculates the comprehensive comparison information. The comparison processing unit 34 determines whether the information in the comparison value table has been updated (S51). If the information in the comparison value table has not been updated (S51, No), the process of step S51 is repeated. If the information in the comparison value table has been updated (S51, Yes), the comparison processing unit 34 checks whether or not all comparison values on the route are in the comparison value table (S52).

  If there is a comparison value that has not been prepared yet (S52, No), the process returns to step S51 and the subsequent processing is repeated. When all the comparison values are available (S52, Yes), the comparison processing unit 34 multiplies all the comparison values on the path in the comparison value table (S53), and the result is the total comparison value. To the upper control layer time management unit 32 (S54). The total comparison value is equal to the ratio of the amount of change in time information between the upper control layer time management unit 22 of the transmission source communication device 2 and the upper control layer time management unit 32 of the reception destination communication device 3.

  FIG. 17 shows that the total comparison value is the amount of change in time information in the upper control layer time management unit 22 of the transmission source communication device 2 and the amount of change in time information in the upper control layer time management unit 32 of the destination communication device 3. It is a figure for demonstrating that it is equal to ratio. The clock diagram in FIG. 17 represents the consistency of the synchronization timing, and the time information of the combination portion in the same clock diagram indicates that the amount of change is equal.

  For example, the synchronization timing of the first synchronous communication network 4 includes the lower communication layer time management unit 27 of the transmission source communication device 2 that is in contact with the first synchronous communication network 4, and the first time management unit 15 of the communication device 1a. It can be seen that it is in a synchronized state. And about the location where the time information which adjoins on a communication path | route is not synchronizing, the comparison value which shows the difference in the synchronization timing exists.

In FIG. 17A, there are four comparison values C _S1 , C ₁₂ , C ₂₃ , and C _3R . When these four comparison values are multiplied, as shown in FIG. Since the difference in synchronization timing is offset, the amount of change in time information in the upper control layer time management unit 22 of the source communication device 2 and the amount of change in time information in the upper control layer time management unit 32 of the destination communication device 3 It can be seen that a _total comparison value C _{total which} is a ratio to the above is obtained.

  As described above, the upper control layer time management unit 32 of the destination communication device 3 calculates the total comparison value, and the time information generated from the free-running clock possessed by the upper control layer time management unit 32 of the reception destination communication device 3. By multiplying the calculated total comparison value, the corrected time information that generates the same time change as the time information generated from the self-running clock of the higher control layer time management unit 22 of the transmission source communication device 2 is generated. Is possible.

  As described above, in the present embodiment, the transmission source communication device 2 and the communication device 1 respectively transmit device identification information and a comparison value to the reception destination communication device 3, and the reception destination communication device 3 receives the device identification information. Since the time information is corrected by calculating the total comparison value based on the comparison value, the time information in the higher layer of the transmission source communication device 2 and the reception destination without matching the synchronization timing in the synchronous communication network Only the time information in the upper layer of the communication device 3 can be synchronized.

(Second Embodiment)
The functional configurations and processing procedures of the communication device 1, the transmission source communication device 2, and the reception destination communication device 3 in the second embodiment of the present invention are the same as those described in the first embodiment of the present invention and the following. It is the same except for the point. Therefore, detailed description of overlapping configurations and functions will not be repeated.

  FIG.10 (b) is a figure which shows an example of the fixed form comparison information in the 2nd Embodiment of this invention. This fixed form comparison information has a field for storing all device identification information and comparison values on the path from the transmission source communication device 2 to the reception destination communication device 3. Whether the frame construction unit 23 of the transmission source communication device 2 and the frame processing unit 11 of the communication device 1 perform the comparison value storing process using the acquisition counter or the random number generation device as described in the first embodiment. The comparison value and the identification information calculated by itself are always stored in the standard comparison information of the frame.

  Further, when a comparison value cannot be obtained due to an error or the like, a value indicating invalidity is stored in a place where a predetermined comparison value of the fixed form comparison information is stored. For example, “0xFFFFFFFF” or “0x00000000” is used as a value indicating invalidity.

  FIG. 18 is a flowchart for explaining the calculation of the total comparison value by the comparison processing unit 34 of the destination communication device 3 in the second embodiment. First, the comparison processing unit 34 determines whether or not the information in the comparison value table has been updated (S61). If the information in the comparison value table has not been updated (S61, No), the process of step S61 is repeated.

  If the information in the comparison value table has been updated (S61, Yes), the comparison processing unit 34 determines whether or not all comparison values on the path stored in the comparison value table are valid. (S62). Whether or not the comparison value is valid is determined by confirming that the comparison value as described above is not “0xFFFFFFFF” or “0x00000000”.

  If there is a comparison value that is not valid (S62, No), the process returns to step S61 and the subsequent processing is repeated. If all the comparison values are valid (S62, Yes), the comparison processing unit 34 multiplies all the comparison values on the path in the comparison value table (S63), and the result is the total comparison value. To the upper control layer time management unit 32 (S64).

  As described above, in the present embodiment, the frame construction unit 23 of the transmission source communication device 2 and the frame processing unit 11 of the communication device 1 store the comparison values calculated by themselves in the frame-shaped comparison information. Since the destination communication device 3 calculates the total comparison value based on the fixed form comparison information and corrects the time information, it is possible to achieve the same effect as described in the first embodiment. It became.

(Third embodiment)
The functional configurations and processing procedures of the communication device 1, the transmission source communication device 2, and the reception destination communication device 3 in the third embodiment of the present invention are the same as those described in the first embodiment of the present invention and the following. It is the same except for the point. Therefore, detailed description of overlapping configurations and functions will not be repeated.

  FIG.10 (c) is a figure which shows the connection type comparison information in the 3rd Embodiment of this invention. In the first embodiment, only one field for storing a comparison value is prepared in the basic type comparison information. Therefore, when a valid comparison value is already stored, the frame processing of the communication device 1 is performed. The unit 11 does not perform comparison value acquisition processing. In the connection type comparison information according to the present embodiment, the field for storing the device identification information and the comparison value is a variable length type, and even if a valid value is already stored, the frame processing unit of the communication device 1 11 can add the identification information acquired from the identification information storage unit 12 and the comparison value calculated by the comparison processing unit 13.

  When adding the identification information and the comparison value, the frame processing unit 11 increments the concatenated value stored in the concatenated value field of the concatenated comparison information by one. In this connection value, 0 is stored when there is no comparison value in the connection type comparison information.

  In addition, the calculation of the total comparison value by the comparison processing unit 34 of the destination communication device 3 is the same as the processing procedure described with reference to the flowchart of FIG.

  As described above, in the present embodiment, the frame construction unit 23 of the transmission source communication device 2 and the frame processing unit 11 of the communication device 1 compare the device identification information and the comparison calculated by itself with the frame connection type comparison information. Since the value is added and the destination communication device 3 calculates the total comparison value based on the connection type comparison information and corrects the time information, the same effect as described in the first embodiment can be obtained. It became possible to play.

(Fourth embodiment)
The functional configurations and processing procedures of the communication device 1, the transmission source communication device 2, and the reception destination communication device 3 in the fourth embodiment of the present invention are the same as those described in the first embodiment of the present invention and the following. It is the same except for the point. Therefore, detailed description of overlapping configurations and functions will not be repeated.

  FIG. 10D is a diagram showing cumulative comparison information according to the fourth embodiment of the present invention. This cumulative comparison information includes a cumulative flag and a cumulative comparison value. The accumulation flag is a flag indicating whether or not the information of the accumulation comparison value is valid. The frame construction unit 23 of the transmission source communication device 2 acquires the comparison value from the comparison processing unit 24 and sets it to the cumulative comparison value of the cumulative type comparison information. At this time, the accumulation flag is set to a value indicating validity.

  When the accumulation flag is valid, the frame processing unit 11 of the communication device 1 always acquires the comparison value from the comparison processing unit 13, multiplies the comparison value and the accumulated comparison value stored in the accumulation type comparison information, Using the result as a new cumulative comparison value, the cumulative comparison value field of the cumulative comparison information is overwritten. If the comparison value cannot be acquired due to an error or the like, the accumulation flag of the accumulation type comparison information is invalidated.

  The frame analysis unit 33 of the destination communication device 3 sends the cumulative comparison information to the comparison processing unit 34 only when the cumulative flag of the cumulative type comparison information is valid. The comparison processing unit 34 obtains total comparison information by multiplying the comparison value calculated from the time information of the upper control layer time management unit 32 and the time information of the lower communication layer time management unit 36 and the cumulative comparison value.

  As described above, in the present embodiment, the frame processing unit 11 of the communication device 1 stores a value obtained by multiplying the cumulative comparison information of the frame by the comparison value calculated by itself and the cumulative comparison value. Since the destination communication device 3 calculates the total comparison value based on the cumulative comparison information and corrects the time information, it is possible to achieve the same effect as described in the first embodiment. became.

  Further, since all the comparison information on the path from the transmission source communication device 2 to the reception destination communication device 3 is accumulated, the device identification information becomes unnecessary, and the amount of information stored in the frame can be reduced.

(Fifth embodiment)
The functional configurations and processing procedures of the communication device 1, the transmission source communication device 2, and the reception destination communication device 3 in the fifth embodiment of the present invention are the same as those described in the first embodiment of the present invention and the following. It is the same except for the point. Therefore, detailed description of overlapping configurations and functions will not be repeated.

  FIG. 11B is a diagram illustrating a format example of a control frame with a comparison information field. The control frame with the comparison information field includes a control identifier indicating that it is a control frame, a control command, a control data storage area, and a comparison information field.

  FIG. 19 is a flowchart for explaining the processing procedure of the communication device 1 according to the fifth embodiment of the present invention. In addition, the following description is about the case of connection type comparison information as an example.

  The first communication management unit 14 of the communication device 1 determines whether a control frame is received from the first synchronous communication network 4 (S71). If the control frame has not been received (S71, No), the process proceeds to step S76. If the control frame is received (S71, Yes), the first communication management unit 14 sends the control frame to the frame processing unit 11. The frame processing unit 11 analyzes the received control frame (S72) and determines whether comparison information is included in the control frame (S73).

  If comparison information is not included in the control frame (S73, No), the process proceeds to step S75. If the comparison information is included in the control frame (S73, Yes), the frame processing unit 11 stores the information (S74) and executes the control process indicated by the control frame (S75). ). In addition, about a control process, it follows the protocol specification which the 1st synchronous communication network 4 employ | adopts.

  Next, the frame processing unit 11 determines whether or not it is necessary to send a control frame to the second synchronous communication network 5 (S76). If it is not necessary to send out the control frame (S76, No), the process returns to step S71 and the subsequent processing is repeated. If it is necessary to send a control frame (S76, Yes), a control frame instructing the control content is generated (S77). Note that the conditions, timing, and instruction contents for sending the control frame are in accordance with the protocol specifications adopted by the second synchronous communication network 5.

  Next, the frame processing unit 11 determines whether comparison information is stored (S79). If the comparison information is not stored (S79, No), the process proceeds to step S81. If the comparison information is stored (S79, Yes), the comparison information is added to the generated control frame (S80). Then, the frame processing unit 11 sends the generated control frame to the second communication management unit 16, and the second communication management unit 16 sends the control frame to the second synchronous communication network 5 (S81).

  As described above, in the present embodiment, the frame processing unit 11 of the communication device 1 adds the comparison value to the control frame, and the destination communication device 3 is based on the comparison information added to the control frame. Since the comparison value is calculated and the time information is corrected, it is possible to achieve the same effect as described in the first embodiment.

  Further, since the communication device 1 can relay the comparison information by the control frame, it is possible to transmit the comparison information to the destination communication device 3. The control frame is given as an example of a frame that can be transmitted only within one synchronous communication network, and the same processing can be performed using a data frame.

(Sixth embodiment)
The functional configurations and processing procedures of the communication device 1, the transmission source communication device 2, and the reception destination communication device 3 in the sixth embodiment of the present invention are the same as those described in the first embodiment of the present invention and the following. It is the same except for the point. Therefore, detailed description of overlapping configurations and functions will not be repeated.

  FIG. 11 (c) is a diagram illustrating an example of a dedicated frame in the sixth embodiment of the present invention. This dedicated frame is a frame intended to transmit comparison information, and includes a dedicated identifier indicating that it is a dedicated frame for comparison information, a reception destination address, a transmission source address, and a comparison information field.

  In the present embodiment, the comparison information is transmitted in a dedicated frame, and the processing procedure of the communication device 1, the transmission source communication device 2, and the reception destination communication device 3 is performed when the comparison information is transmitted by a data frame or in the control. This is the same as when comparison information is transmitted by frame.

  As described above, in the present embodiment, the frame construction unit 23 of the transmission source communication device 2 and the frame processing unit 11 of the communication device 1 store the comparison values calculated by themselves in the dedicated frame, and receive destination communication Since the device 3 calculates the total comparison value based on the comparison information stored in the dedicated frame and corrects the time information, it is possible to achieve the same effect as described in the first embodiment. It became.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a block diagram which shows schematic structure of the transmission path | route in the 1st Embodiment of this invention. It is a figure which shows the example of an external appearance of the communication apparatus 1 in the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the communication apparatus 1 in the 1st Embodiment of this invention. It is a block diagram which shows the functional structure of the communication apparatus 1 in the 1st Embodiment of this invention. It is a block diagram which shows the functional structure of the transmission origin communication apparatus 2 in the 1st Embodiment of this invention. It is a block diagram which shows the functional structure of the receiver communication apparatus 3 in the 1st Embodiment of this invention. It is a flowchart for demonstrating the process sequence of the transmission origin communication apparatus 2 in the 1st Embodiment of this invention. It is a flowchart for demonstrating the process sequence of the communication apparatus 1 in the 1st Embodiment of this invention. It is a flowchart for demonstrating the process sequence of the receiver communication apparatus 3 in the 1st Embodiment of this invention. It is a figure which shows an example of basic type comparison information, fixed form comparison information, connection type comparison information, and accumulation type comparison information. It is a figure which shows an example of a data frame with a comparison information field, a control frame with a comparison information field, and a dedicated frame. It is a figure which shows a comparison information format and a format table. It is a flowchart for demonstrating the process sequence which memorize | stores the time information required in order to calculate a comparison value in a time management table. It is a figure which shows the time management table and the calculation table of a comparison value. It is a figure for demonstrating the process which produces | generates the comprehensive comparison value of the transmission path in the 1st Embodiment of this invention. It is a flowchart for demonstrating the process sequence when the comparison process part 34 of the receiving communication apparatus 3 calculates total comparison information. The total comparison value is equal to the ratio between the amount of change of time information in the upper control layer time management unit 22 of the transmission source communication device 2 and the amount of change of time information in the upper control layer time management unit 32 of the destination communication device 3. It is a figure for demonstrating this. It is a flowchart for demonstrating calculation of the comprehensive comparison value by the comparison process part 34 of the receiving communication apparatus 3 in 2nd Embodiment. It is a flowchart for demonstrating the process sequence of the communication apparatus 1 in the 5th Embodiment of this invention. It is a figure for demonstrating the influence by the difference in the advancement of the clock of the transmission side tuner, and the advancement of the clock of the receiving side television. It is a figure for demonstrating the problem in the case of performing network synchronization of a different communication network.

Explanation of symbols

  1 source communication device, 2 communication device, 3 destination communication device, 4 first synchronous communication network, 5 second synchronous communication network, 6 third synchronous communication network, 11 frame processing unit, 12 identification information storage unit, 13 comparison Processing unit, 14 First communication management unit, 15 First time management unit, 16 Second communication management unit, 17 Second time management unit, 21 Data processing unit, 22 Upper control layer time management unit, 23 Frame construction unit, 24 Comparison processing unit, 25 identification information storage unit, 26 communication management unit, 27 lower communication layer time management unit, 31 data processing unit, 32 upper control layer time management unit, 33 frame analysis unit, 34 comparison processing unit, 35 communication management unit 36, lower communication layer time management unit, 71 computer main body, 72 display device, 73 FD drive, 74 FD, 75 keyboard, 76 mouse, 77 CD-ROM device 78 CD-ROM, 79 network communication unit, 80 CPU, 81 ROM, 82 RAM, 83 hard disk.

Claims (13)

A communication device on a transmission path in which a transmission source communication device and a reception destination communication device perform communication via a plurality of communication devices that connect the communication network and the communication network,
Comparison means for comparing time information generated from synchronization signals of a plurality of communication networks to be connected;
Receiving means for receiving a predetermined frame from the communication network on the transmission source side;
Adding means for adding comparison information including a comparison value obtained by the comparison means and identification information for specifying a communication device corresponding to the comparison value to the predetermined frame received by the reception means; ,
A communication unit including: a transmission unit configured to transmit the predetermined frame to which the comparison information is added by the addition unit to the destination communication device.   The communication device according to claim 1, wherein the predetermined frame includes a field for storing comparison information of a transmission source communication device and comparison information of a plurality of communication devices.   The communication apparatus according to claim 1, wherein the predetermined frame is a variable-length frame, and comparison information of a transmission source communication device and comparison information of a plurality of communication apparatuses are sequentially connected. A communication device on a transmission path in which a transmission source communication device and a reception destination communication device perform communication via a plurality of communication devices that connect the communication network and the communication network,
Comparison means for comparing time information generated from synchronization signals of a plurality of communication networks to be connected;
Receiving means for receiving a predetermined frame from the communication network on the transmission source side;
Storage means for calculating a cumulative comparison value included in the predetermined frame received by the reception means and a comparison value obtained by the comparison means, and storing the calculated value in the predetermined frame as a new cumulative comparison value; ,
And a transmission unit configured to transmit a predetermined frame in which the accumulated comparison value is stored by the storage unit to the destination communication device. The source communication device and the destination communication device are a source communication device on a transmission path for performing communication via a plurality of communication devices that connect the communication network and the communication network,
Comparison means for comparing the time information generated from the synchronization signal of the connected communication network and the time information of the upper control layer,
Generation means for generating a predetermined frame including comparison information obtained by the comparison means and identification information for identifying the transmission source communication device;
A transmission source communication device including a transmission unit for transmitting the predetermined frame generated by the generation unit to the reception destination communication device.   The transmission source communication device according to claim 5, wherein the predetermined frame includes a field for storing comparison information of the transmission source communication device and comparison information of a plurality of communication devices. A source communication device and a destination communication device are a destination communication device on a transmission path for performing communication via a plurality of communication devices that connect the communication network and the communication network,
A comparison value between time information generated from a synchronization signal of a communication network to which the transmission source communication device is connected and time information of an upper control layer of the transmission source communication device, and a plurality of communication networks to which the communication device is connected Receiving means for receiving a comparison value of time information generated from the synchronization signal of
Based on the comparison value of the transmission source communication device and the comparison value of the communication device received by the reception unit, the time information of the upper control layer of the transmission source communication device and the time of the upper layer of the reception destination communication device Receiving destination communication equipment, including control means for matching information. A computer program for causing a computer to execute a communication method of a communication device on a transmission path in which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. Because
The communication method includes a step of comparing time information generated from synchronization signals of a plurality of communication networks to be connected;
Receiving a predetermined frame from the communication network on the transmission side;
Adding comparison information having identification information for specifying the obtained comparison value and a communication device corresponding to the comparison value to the received predetermined frame;
Transmitting a predetermined frame to which the comparison information is added to the receiving communication device. A computer for causing a computer to execute a communication method of a transmission source communication device on a transmission path in which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. A program,
The communication method includes a step of comparing time information generated from a synchronization signal of a connected communication network with time information of an upper control layer;
Generating a predetermined frame including comparison information having identification information for specifying the obtained comparison value and the source communication device;
Transmitting the generated predetermined frame to the receiving communication device. Computer for causing a computer to execute a communication method of a destination communication device on a transmission path in which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network A program,
In the communication method, a comparison value between time information generated from a synchronization signal of a communication network to which the transmission source communication device is connected and time information of an upper control layer of the transmission source communication device, and the communication device are connected. Receiving a comparison value of time information generated from synchronization signals of a plurality of communication networks.
Based on the received comparison value of the transmission source communication device and the comparison value of the communication device, the time information of the upper control layer of the transmission source communication device and the time information of the upper layer of the reception destination communication device. A computer program comprising the steps of aligning. Records a program for causing a computer to execute a communication method of a communication device on a transmission path in which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. A computer-readable recording medium,
The communication method includes a step of comparing time information generated from synchronization signals of a plurality of communication networks to be connected;
Receiving a predetermined frame from the communication network on the transmission side;
Adding comparison information including identification information for specifying the obtained comparison value and a communication device corresponding to the comparison value to the received predetermined frame;
Transmitting a predetermined frame to which the comparison information is added to the receiving communication device. A program for causing a computer to execute a communication method of a transmission source communication device on a transmission path in which a transmission source communication device and a reception destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. A computer-readable recording medium on which is recorded,
The communication method includes a step of comparing time information generated from a synchronization signal of a connected communication network with time information of an upper control layer;
Generating a predetermined frame including comparison information having identification information for specifying the obtained comparison value and the source communication device;
Transmitting the generated predetermined frame to the receiving communication device. A computer-readable recording medium. A program for causing a computer to execute a communication method of a destination communication device on a transmission path in which a transmission source communication device and a destination communication device communicate via a plurality of communication devices that connect the communication network and the communication network. A computer-readable recording medium on which is recorded,
In the communication method, a comparison value between time information generated from a synchronization signal of a communication network to which the transmission source communication device is connected and time information of an upper control layer of the transmission source communication device, and the communication device are connected. Receiving a comparison value of time information generated from synchronization signals of a plurality of communication networks.
Based on the received comparison value of the transmission source communication device and the comparison value of the communication device, the time information of the upper control layer of the transmission source communication device and the time information of the upper layer of the reception destination communication device. A computer-readable recording medium comprising the steps of aligning.

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