JP5781272B2 - Communication device, master-slave determination method, and computer program - Google Patents

Description

  The present invention relates to a communication device such as an SHDSL modem and a method for determining a role in the communication device.

  Conventionally, communication devices such as two modems communicate with each other by various communication methods. For example, according to the Symmetric Digital Subscriber Line (SDSL) system, two modems perform communication from one modem to the other modem and communication in the opposite direction via the pair of telephone lines at the same speed. Further, according to the Symmetric High-speed Digital Subscriber Line (SHDSL) system, communication can be performed at a higher speed than the SDSL system, and the length of the telephone line can be made longer than that of the SDSL system.

  When communication is performed by two communication devices such as two modems via a telephone line or the like, usually one communication device is set as a master and the other communication device is set as a slave (Non-Patent Document 1).

Rad Japan Co., Ltd. website, “ASM-31”, URL “http://www.raddata.co.jp/Article/0,6583,39296-2-Wire_Multirate_Short_Range_Modem,00.html”, January 24, 2010 Day search

  In a large site such as a factory, when two communication devices such as modems are fixedly installed at a remote location and communication for in-house transmission is performed, an operation and maintenance person plans to build a communication environment in advance. At this time, the operation and maintenance person sets one communication device as a master and the other communication device as a slave.

  However, when it is necessary to build a communication environment that temporarily connects two locations, for example, when a disaster occurs, one of the two communication devices is set as the master and the other is set as the slave. Work must be done promptly.

  However, in the conventional method, it takes time and effort for planning and setting by an operation and maintenance person, and it takes time until an environment for communication is established.

  The present invention has been made in view of such problems, and an object of the present invention is to make it possible to determine the roles of two communication devices such as modems more easily than in the past.

A communication device according to an aspect of the present invention is a communication device that communicates with another communication device, and when a first value is set in the first register, a handshaking message is exchanged with the communication device. Communication control means using a driver and physical layer control firmware that sets the second value in the second register when handshaking is established, and communication with the other communication device using the communication device as a master A master mode setting command means of a master mode processing unit for setting a master mode to be set for the communication control means, and when the master mode setting command means sets the master mode for the communication control means, handshaking open by the mode determination processing start command unit of the master mode processing unit for setting the first value to 1 in the register An instruction unit, wherein the communication device and a slave mode setting command means in the slave mode processing unit for setting to the communication control means slave mode to communicate with the other communication devices as a slave, the first and second registers In a period when the value of 2 is not set, it is determined on the basis of a random number that is a time interval longer than the time required for exchanging all the handshaking messages to the master mode setting command means and the slave mode setting command means. Switching means for alternately setting a mode for the communication control means at random time intervals .

  According to the present invention, the role of communication devices such as two modems can be determined more easily than before.

It is a figure which shows the example of the whole structure of a wide area network. It is a figure which shows the example of the hardware constitutions of a modem. It is a figure which shows the example of a functional structure of a modem. It is a figure which shows the example of exchange of a handshaking message. It is a flowchart explaining the example of the flow of the whole process of the modem at the time of link establishment. It is a flowchart explaining the example of the flow of the whole process of the modem at the time of link establishment. It is a figure which shows the example of exchange of a handshaking message. It is a figure which shows the example of exchange of a handshaking message. It is a figure which shows the example of exchange of a handshaking message. It is a figure which shows the example of exchange of a handshaking message. It is a figure which shows the example of the platform of a modem. It is a figure which shows the example of a functional structure implement | achieved by the software for a connection. It is a figure which shows the example of a master mode process part. It is a figure which shows the example of a slave mode process part.

  1 is a diagram illustrating an example of the overall configuration of the wide area network 30, FIG. 2 is a diagram illustrating an example of a hardware configuration of the modem 10, FIG. 3 is a diagram illustrating an example of a functional configuration of the modem 10, and FIG. It is a figure which shows the example of exchange of a handshaking message.

  As shown in FIG. 1, the wide area network 30 includes a plurality of local area networks 40. Hereinafter, each local area network 40 may be described separately as “local area network 40A”, “local area network 40B”, “local area network 40C”,.

  The local area network 40 includes a modem 10, a hub 11, and one or a plurality of terminal devices 12.

  The hub 11 relays communication between the modem 10 in the local area network 40 to which the hub 11 belongs and each terminal device 12.

  The modem 10 communicates with other modems 10 by a communication method such as Symmetric Digital Subscriber Line (SDSL) or Symmetric High-speed Digital Subscriber Line (SHDSL). The modem 10 communicates with the terminal device 12 by a communication method such as Local Area Network (LAN) or wireless LAN.

  More specifically, the modem 10 is connected to another modem 10 by a telephone line such as a metal line. Further, the modem 10 is connected to the hub 11 by a LAN cable or the like. In some cases, the modem 10 is provided with the function of the hub 11.

  Then, the modem 10 transmits data exchanged between the terminal device 12 in the local area network 40 to which the modem 10 belongs and the terminal device 12 in the other local area network 40 to the other local area network 40. Relay via another modem 10 belonging to

  The terminal device 12 is a device provided with an application such as a word processor, e-mail, Web browser, or IP phone. As the terminal device 12, a personal computer or a workstation is used.

  As shown in FIG. 2, the modem 10 includes a micro processing unit (MPU) 10p, a random access memory (RAM) 10q, a read only memory (ROM) 10r, a liquid crystal panel 10s, operation buttons 10t, a communication unit 10u, and the like. .

  The communication unit 10u modulates the digital signal sent from the terminal device 12 via the LAN cable into an analog signal and transmits it to the other modem 10 via the telephone line. Further, the analog signal sent from the other modem 10 via the telephone line is demodulated into a digital signal and transmitted to the terminal device 12 via the LAN cable.

  The operation button 10t is a button for the user to input commands and data to the modem 10.

  The liquid crystal panel 10s displays a command or data input by the user in addition to the state of the modem 10.

  Further, the operation button 10t and the liquid crystal panel 10s may be configured to connect a terminal device having an equivalent function to the outside of the modem 10.

  The ROM 10r includes a master / slave determination unit 101, a random number generation unit 102, a master mode switching processing unit 103, a slave side switching processing unit 104, a master side message exchange processing unit 105, and a slave side message exchange processing unit 106 as shown in FIG. And programs and data for realizing the link establishment processing unit 107 and the like are stored. These programs and data are executed by the MPU 10p.

  According to each part of FIG. 3, the process at the time of newly connecting the modem 10 to the other modem 10 can be performed more easily than before.

  By the way, in general, when two modems 10 are connected, an operation / maintenance person must plan and set that one of them plays the role of a master and the other plays the role of a slave.

  At the time of establishing a connection, that is, a link, a message exchanged between the master and the slave is first transmitted from the master side as shown in FIG. That is, first, the master transmits (sends) a message MG1 having a specific content to the slave via the telephone line.

  When receiving the message MG1, the slave transmits a message MG2 indicating a specific content to the master as a response message to the slave. Hereinafter, similarly, the master and the slave exchange messages according to the communication method. When all message exchanges are completed, a link is established between the master and the slave by setting the conventional line according to the role at that time.

  Next, the processing content of each part of the modem 10 shown in FIG. 3 will be described in detail.

  The master / slave determination unit 101 determines whether the modem 10 itself operates as a master or a slave. Hereinafter, a mode operating as a master is referred to as “master mode”, and a mode operating as a slave is referred to as “slave mode”.

  The master / slave determination unit 101 determines whether the mode of the modem 10 itself is set to the master mode or the slave mode in cooperation with the random number generation unit 102 as follows.

  When the power supply of the modem 10 is turned on, the master / slave determination unit 101 determines a predetermined one of the master mode and the slave mode as the mode of the modem 10 itself. Alternatively, it may be determined which mode is selected by generating a random number.

  The random number generation unit 102 generates a random number within a predetermined range every time the master / slave determination unit 101 determines a mode. This random number is used to represent the number of seconds in which the mode is continued as will be described later.

  The lower limit value of the predetermined range is preferably equal to or longer than the time necessary for completing the exchange of handshaking messages when the master and the slave determine the mode. For example, if the time required for exchanging handshaking messages is 2 to 3 seconds, the lower limit is set to about “3” to “5”.

  On the other hand, the upper limit value of the predetermined range may be any value, but it is better not to be too large. For example, it is set to about “20” to “60”.

  Furthermore, after determining the mode, when the time (seconds) for the random number generated by the random number generation unit 102 elapses, the master / slave determination unit 101 determines the mode to be different from the current mode.

  Further, even after the master / slave determination unit 101 determines the mode again, the random number generation unit 102 generates a random number. Then, when the time (seconds) corresponding to the random number has elapsed, master / slave determination unit 101 determines the mode to be different from the current mode.

  Therefore, according to master slave determination unit 101 and random number generation unit 102, the mode of modem 10 is determined as a master mode, a slave mode, a master mode, a slave mode,... At random time intervals. Alternatively, the slave mode, the master mode, the slave mode, the master mode,... Are determined at random time intervals. The determination process is stopped when it is determined that the handshaking message exchange with the other modem 10 has been normally completed.

  The master mode switching processing unit 103 switches the mode of the modem 10 itself to the master mode at the timing when the mode is determined or re-determined as the master mode by the master / slave determination unit 101.

  The slave side switching processing unit 104 switches the mode of the modem 10 itself to the slave mode at the timing when the mode is determined or re-determined as the slave mode by the master / slave determination unit 101.

  Master-side message exchange processing unit 105 transmits message MG1 to the slave at the timing when the mode of modem 10 is switched to master mode by master mode switching processing unit 103. Further, according to the communication method, a message (handshaking message) is exchanged with the slave, such as receiving a message from the slave and transmitting a specific message to the slave. The message exchange is as described with reference to FIG.

  The slave-side message exchange processing unit 106 waits for the message MG1 to be transmitted from the master at the timing when the mode of the modem 10 is switched to the slave mode by the slave-side switching processing unit 104. When message MG1 is received, a message (handshaking message) is exchanged with the master as described in FIG. 4 according to the communication method.

  The link establishment processing unit 107 determines that the mode has been established by successfully completing the handshaking message exchange with the other modem 10 that is the connection partner, and establishes a link with the other modem 10. Perform processing such as setting the line to complete the establishment of the network.

  FIGS. 5 and 6 are flowcharts for explaining an example of the overall processing flow of the modem 10 at the time of establishing a link, and FIGS. 7 to 10 are diagrams showing an example of handshaking message exchange.

  Next, with reference to an example in which the modem 10 of the local area network 40A shown in FIG. 1 is not yet connected to the modem 10 of the local area network 40B and will be newly connected, the processing procedure of each unit in FIG. This will be described with reference to the flowcharts shown in FIGS. Hereinafter, the modems 10 of the local area network 40A and the local area network 40B will be described separately from “modem 10A” and “modem 10B”.

  A user in the local area network 40A connects a telephone line laid between the local area network 40A and the local area network 40B to the modem 10A. Further, the modem 10A is turned on.

  Then, in the modem 10A, the master / slave determination unit 101 determines the mode of the modem 10A to be either the master mode or the slave mode (# 71 in FIG. 5). If the master mode is determined (Yes in # 72), the random number generator 102 generates a random number within a predetermined range (# 73). Before or after or in parallel with the random number generation process, the master / slave determination unit 101 resets the hardware setting values (# 74), and the master mode switching processing unit 103 sets the mode of the modem 10A to the master mode. (# 75).

  The master-side message exchange processing unit 105 exchanges a handshaking message with the modem 10B as a master (# 77). Therefore, master side message exchange processing unit 105 transmits message MG1, which is the first message, to modem 10B.

  When the modem 10B is operating as a slave, the message MG1 is received by the modem 10B, so the master-side message exchange processing unit 105 can start exchanging handshaking messages. However, otherwise it cannot be started.

  Therefore, the master-side message exchange processing unit 105 tries to exchange handshaking messages for the time corresponding to the random number generated in step # 73. That is, the master-side message exchange processing unit 105 transmits the message MG1 periodically (for example, every 0.1 to 0.5 seconds).

  When the handshaking message exchange is completed within the time (Yes in # 78), the link establishment processing unit 107 determines that the modem 10B is operating as a slave, thereby changing the mode of the modem 10A. The master is determined (# 79). Then, the modem 10A performs various settings relating to the line and the like as usual (# 80).

  On the other hand, when the exchange of the handshaking message cannot be completed within the time (No in # 78, Yes in # 76), the master / slave determination unit 101 re-determines the mode of the modem 10A to the slave mode. Appropriately executes the processing shown in FIG. Also, when the power is turned on and the mode of the modem 10A is first determined to be the slave mode (No in # 72), each unit executes the processing shown in FIG.

  The random number generator 102 generates random numbers within a predetermined range (# 81). Before or after or in parallel with the random number generation processing, the master / slave determination unit 101 resets the hardware setting values (# 82), and the slave side switching processing unit 104 sets the mode of the modem 10A to the slave mode. (# 83).

  The slave-side message exchange processing unit 106 exchanges a handshaking message with the modem 10B as a slave (# 85). Therefore, the slave-side message exchange processing unit 106 waits for the message MG1, which is the first message, to be transmitted from the modem 10B.

  When the modem 10B is operating as a master, the message MG1 is transmitted, so that the slave-side message exchange processing unit 106 can start exchanging handshaking messages when receiving the message MG1. However, otherwise it cannot be started.

  Therefore, the slave-side message exchange processing unit 106 tries to exchange the handshaking message for the time corresponding to the random number generated in step # 81. That is, the message MG1 is kept waiting for that time.

  If the handshaking message exchange is completed within the time (Yes in # 86), the link establishment processing unit 107 determines that the modem 10B is operating as a master, and thereby changes the mode of the modem 10A. The slave is determined (# 87). Then, the modem 10A performs various settings relating to the line and the like as usual (# 88).

  On the other hand, if the handshaking message exchange cannot be completed in time (No in # 86, Yes in # 84), the master / slave determination unit 101 re-determines the mode of the modem 10A as the master mode, Appropriately executes the processes of steps # 74 to # 80 shown in FIG.

  Similarly, the user in the local area network 40B connects the telephone line laid between the local area network 40A and the local area network 40B to the modem 10B. Further, the modem 10B is turned on.

  Then, the modem 10B also appropriately executes each process shown in FIGS. 5 and 6 with the modem 10A as a counterpart.

  As a result, the modes of the modem 10A and the modem 10B change randomly. Therefore, as shown in FIG. 7 or FIG. 8, there is a time zone in which one modem 10 is in the master mode and the other modem 10 is in the slave mode. In this time zone, the modem 10A and the modem 10B can exchange handshaking messages to determine the mode.

  As shown in FIG. 9 or FIG. 10, if the mode of one modem 10 is switched during the handshaking message exchange, the handshaking message exchange cannot be completed. The mode cannot be determined. However, even in such a case, the modes of the modem 10A and the modem 10B change at random time intervals. Therefore, the modem 10A and the modem 10B can obtain the opportunity of exchanging handshaking messages again, and can determine the mode.

  According to the present embodiment, the user can perform the role assignment of the master and slave of the two modems 10 more easily than in the past without making a prior plan.

[Example of modem compatible with SHDSL]
11 is a diagram showing an example of the platform of the modem 50, FIG. 12 is a diagram showing an example of a functional configuration realized by the connection software 563, FIG. 13 is a diagram showing an example of the master mode processing unit 504, and FIG. It is a figure which shows the example of the slave mode process part.

  Next, a description will be given of an embodiment in which an SHDSL compatible modem 50 is used as the modem 10 and an existing driver is used.

  The overall configuration of the wide area network 30 is as shown in FIG. The hardware configuration of the modem 50 is basically the same as the hardware configuration of the modem 10 shown in FIG. That is, as shown in FIG. 11, the modem 50 includes an MPU 50p, a RAM 50q, a ROM 50r, a liquid crystal panel 50s, operation buttons 50t, a communication unit 50u, and the like.

  However, the ROM 50r of the modem 50 stores physical layer control firmware 561, a driver 562, and connection software 563, as shown in FIG.

  The physical layer control firmware 561 is a program for controlling each hardware so that communication is performed according to SHDSL and Ethernet (registered trademark). Furthermore, Application Program Interface (API) is prepared for the physical layer control firmware.

  The driver 562 is a program for controlling the hardware of the modem 50 by appropriately calling an API function (function) prepared in the physical layer control firmware 561.

  The physical layer control firmware 561 and the driver 562 are prepared in advance by the vendor of the modem 50. Depending on the model, the physical layer control firmware 561 and the driver 562 may be integrally configured as a set of software (firmware).

  Incidentally, the standard of the telephone line (2BASE-TL) used in SHDSL is defined by Institute of Electrical and Electronics Engineers (IEEE) 802.3. Therefore, the physical layer control firmware 561 and the driver 562 are compliant with IEEE 802.3. The driver 562 includes a register defined by IEEE802.3.

  The connection software 563 is software for performing processing when a modem 50 itself is newly connected to another modem 50 more easily than in the past. That is, it basically plays the same role as each part shown in FIG.

  However, in the example of FIG. 11, the functions of the units illustrated in FIG. 3 are realized not only by the connection software 563 but also by the physical layer control firmware 561 and the driver 562.

  The connection software 563 includes a program for realizing a master / slave determination unit 501, a reset command unit 502, a master / slave switching unit 503, a master mode processing unit 504, and a slave mode processing unit 505 as shown in FIG. Contains data. These programs are executed by the MPU 50p.

  Next, processing contents of each unit of the modem 50 shown in FIG. 12 will be described. Note that a description of items common to those described in FIG. 3 is omitted.

  The master slave determination unit 501 determines whether the mode of the modem 50 itself is set to the master mode or the slave mode, similarly to the master slave determination unit 101 of FIG.

  The reset command unit 502 resets hardware setting values and the like every time the master / slave determination unit 501 determines a mode. The reset may be performed, for example, by designating a reset command or API function to the driver 562 or the physical layer control firmware 561.

  When the master slave determination unit 501 determines the mode to be the master mode, the master slave switching unit 503 enables the master mode processing unit 504 and disables the slave mode processing unit 505. On the other hand, when the master / slave determination unit 501 determines the mode to be the slave mode, the master / slave switching unit 503 enables the slave mode processing unit 505 and disables the master mode processing unit 504.

  As shown in FIG. 13, the master mode processing unit 504 includes a master mode setting command unit 571, a mode determination processing start command unit 572, a random number generation unit 573, a mode determination check unit 574, a line setting command unit 575, and the like. With such a configuration, the master mode processing unit 504 performs processing for connecting to another modem 50 as a master. This process is started at the timing when the master mode processing unit 504 is effectively switched by the master / slave switching unit 503.

  The master mode setting command unit 571 causes the driver 562 or the physical layer control firmware 561 to perform processing for setting the mode of the modem 50 itself to the master mode. At this time, the master mode setting command unit 571 may specify a command or API function for switching to the master mode to the driver 562 or the physical layer control firmware 561. Then, the driver 562 or the physical layer control firmware 561 sets the mode to the master mode. The same applies to the setting of the slave mode by a slave mode setting command unit 581 (see FIG. 14) described later.

  The mode confirmation processing start command unit 572 instructs the driver 562 to start exchanging handshaking messages as a master after the setting to the master mode is completed. The command is “Regulation 6.16 of IEEE802.3”, that is, “Get (BitVal = 10)” in “Discovery Operation (Bit [1: 0])” of the register “45.2.6.6 10P / 2B aggregation discovery control register (Register 6.16)”. ”Is set. Then, the communication unit 50u and the like are controlled by the driver 562 and the physical layer control firmware 561, and the first message, that is, the message MG1 is transmitted to the other party.

  The random number generator 573 generates a random number within a predetermined range every time the master mode is set.

  The mode confirmation checking unit 574 determines whether or not a link with another modem 50 has been established until the time (seconds) of the random number generated by the random number generation unit 573 has elapsed since the master mode was set. Check as follows.

  The mode confirmation check unit 574 reads out the value of “Remote PAF supported Bit [11]” of the register of IEEE802.3 Reg3.60, that is, “45.2.3.17 10P / 2B capability register (register 3.60)”. Then, the mode confirmation checking unit 574 determines that the exchange of the handshaking message has been normally completed because the read value has changed to “link partner supports PAF (BitVal = 1)”, and determines that the mode has been confirmed. To do. Otherwise, it is determined that the mode has not been determined.

Here, it is premised that the value of “PAF available Bit [12]” in Reg 3.60 of IEEE 802.3 is “PAF supported (BitVal = 1)” between itself and the other modem 50. (PAF: Abbreviation for PME Aggregation Function, which is a function commonly implemented in SHDSL chips.)
When the mode determination check unit 574 determines (detects) that the mode has been determined, the line setting command unit 575 performs line setting with the mode of the modem 50 itself as the master mode. For example, by specifying a command for setting a line or an API function to the driver 562 or the physical layer control firmware 561, various settings relating to the line etc. for the modem 50 to operate as a master can be set. Just do it.

  Returning to FIG. 12, the slave mode processing unit 505 includes a slave mode setting command unit 581, a random number generation unit 582, a mode confirmation check unit 583, a line setting command unit 584, and the like as shown in FIG. 14. With such a configuration, the slave mode processing unit 505 performs processing for connecting to another modem 50 as a slave. This process is started at the timing when the slave mode processing unit 505 is effectively switched by the master / slave switching unit 503.

  The slave mode setting command unit 581 causes the driver 562 or the physical layer control firmware 561 to perform processing for setting the mode of the modem 50 itself to the slave mode.

  The random number generator 582 generates a random number within a predetermined range every time the slave mode is set.

  The mode confirmation check unit 583 determines whether or not a link with another modem 50 has been established until the time (seconds) of the random number generated by the random number generation unit 573 has elapsed since the slave mode was set. To check. The checking method is the same as the checking method by the mode confirmation checking unit 574 described above. In other words, the mode confirmation checking unit 583 changes the value of “Remote PAF supported Bit [11]” in Reg3.60 of IEEE 802.3 to “link partner supports PAF (BitVal = 1)”. It is determined that the exchange has been completed normally, and it is determined that the mode has been determined. Otherwise, it is determined that the mode has not been determined.

  When the mode determination check unit 583 determines (detects) that the mode has been determined, the line setting command unit 584 performs line setting with the mode of the modem 50 itself as the slave mode. For example, as in the case of the line setting command unit 575, the setting is made so that the modem 50 itself operates as a slave by specifying a line setting command or API function to the driver 562 or the physical layer control firmware 561. Various settings relating to the line and the like may be made.

  Returning to FIG. 12, the master / slave determination unit 501 determines that the mode determination check unit 574 or the mode determination check unit 583 determines the mode even when the time corresponding to the random number generated by the random number generation unit 573 or the random number generation unit 582 has elapsed. Is not detected, the mode of the modem 50 itself is determined again as a mode opposite to the current mode.

  With such a configuration, the mode of the modem 50 is determined as a master mode, a slave mode, a master mode, a slave mode,... At random time intervals within a predetermined range. Alternatively, the slave mode, the master mode, the slave mode, the master mode,... Are determined at similar time intervals. When the handshaking message exchange with the other modem 50 is normally completed, the mode is determined and the determination process is stopped.

  The overall processing flow of the modem 50 is basically as described above with reference to the flowcharts shown in FIGS. Hereinafter, processing of each step when an existing driver or the like is used in the modem 50 will be described.

  The local area network 40A includes a modem 50A as the modem 50. On the other hand, the local area network 40B is provided with a modem 50B as the modem 50. The modem 50A and the modem 50B are not yet connected, and a connection is attempted from now on.

  A user in the local area network 40A connects a telephone line laid between the local area network 40A and the local area network 40B to the modem 50A. Further, the modem 50A is turned on.

  Then, the modem 50A executes the same process as the modem 10A. That is, in the modem 50A, the master / slave determination unit 501, the reset command unit 502, and the master / slave switching unit 503 repeatedly switch the mode of the modem 50A to either the master mode or the slave mode at random time intervals (FIG. 5). # 71 to # 75, # 81 to # 83 in FIG.

  While in the master mode, the master mode processing unit 504 attempts to determine the mode with the modem 50B as a master (# 77). At this time, the master mode processing unit 504 sets “Get (BitVal = 10)” in “Discovery Operation (Bit [1: 0])” of Reg 6.16. As a result, the communication unit 50u is controlled by the physical layer control firmware 561 and the driver 562, and the message MG1 is transmitted to the modem 50B. When the message MG1 is not received by the modem 50B, the message MG1 is periodically transmitted from the modem 50A to the modem 50B until the mode is switched to the slave mode.

  Then, before switching to the slave mode, the message MG1 is received by the modem 50B, and when the exchange of the handshaking message is normally completed (Yes in # 78), the role of the modem 50A is determined as the master, and the line setting is performed. By doing so, a link is established (# 79, # 80). Thereafter, the modem 50A communicates with the modem 50B as a master. The confirmation of the mode can be detected by checking the value of “Remote PAF supported Bit [11]” in Reg 3.60.

  On the other hand, while in the slave mode, the slave mode processing unit 505 attempts to determine the mode with the modem 50B as a slave (# 85). At this time, it waits for the message MG1 to be transmitted from the modem 50B.

  When the message MG1 arrives from the modem 50B and the exchange of the handshaking message is normally completed (Yes in # 86) before switching to the master mode, the role of the modem 50A is determined to be a slave (# 87, # 88) Thereafter, the modem 50A communicates with the modem 50B as a slave. The mode confirmation in the slave mode can also be detected by checking the value of “Remote PAF supported Bit [11]” in Reg 3.60.

  Similarly, the modem 50B appropriately executes the above-described processes according to the procedure shown in FIGS. 5 and 6 with the modem 50A as a counterpart.

  According to the present embodiment, it is possible to easily share the roles of the master and slave of the two modems 10 by using a register prepared in advance and defined by IEEE 802.3.

  In each of the embodiments described above, the time for continuing the master mode and the time for continuing the slave mode are determined at the time of mode determination or redetermination, but other determination methods may be used. For example, after the mode determination or re-determination, the modems 10 and 50 each receive a random number every time a predetermined time (for example, 1 second) elapses after the time required for completing all handshaking message exchanges has elapsed. Is generated. If the generated random number is a predetermined value, the mode is determined again. Otherwise, continue mode.

  In addition, the configuration of the entire wide area network 30, the local area network 40, and the modems 10 and 50, the components, the processing contents, the processing order, and the like can be appropriately changed in accordance with the spirit of the present invention.

10, 50 Modem (communication equipment)
105 Master side message exchange processing unit (master processing means)
106 Slave side message exchange processing unit (slave processing means)
101, 501 Master slave determination unit (switching means)
102 Random number generator (switching means)
103 Master mode switching processing section (switching means)
104 Slave side switching processing section (switching means)
107 link establishment processing unit (confirming means)
503 Master-slave switching unit (switching means)
504 Master mode processing unit (master processing means)
505 Slave mode processing unit (slave processing means)

Claims (3)

A communication device that communicates with other communication devices,
A driver that causes the communication device to exchange handshaking messages when a first value is set in the first register, and sets a second value in the second register when handshaking is established And communication control means by physical layer control firmware ;
A master mode setting command unit of a master mode processing unit that sets a master mode for causing the communication device to communicate with the other communication device as a master for the communication control unit;
When the master mode setting command means sets the master mode to the communication control means, the master mode processing section sets the first value by the mode confirmation process start command section. Handshaking start instruction means;
A slave mode setting command means of a slave mode processing section for setting a slave mode for communicating with the other communication equipment as the slave to the communication control means;
In the second period in which the second value is not set in the register, to the master mode setting command means and said slave mode setting command means, a required time or time interval for exchanging all the handshaking message Switching means for performing mode setting for the communication control means alternately at random time intervals, determined based on random numbers ;
Communication equipment having. Two communication devices that start exchanging handshaking messages when the first value is set in the first register and set the second value in the second register when handshaking is established A master-slave determination method for determining the two communication devices as a master and a slave when establishing a link of
A process of setting a master mode for communicating with the other communication apparatus as the master and setting the first value in the first register in each of the two communication apparatuses; and the other communication apparatus as the slave A process for setting a slave mode to communicate with a random number at a time interval equal to or longer than a required time for exchanging all the handshaking messages during a period when the second value is not set in the second register. Are determined alternately based on each other, and are alternately executed at random time intervals , and when the second value is set in the second register in the master mode, the master is determined, and in the slave mode, the second value is determined. If the second value is set, confirm to the slave,
Master slave determination method. Communication control means for starting handshaking message exchange when the first value is set in the first register and setting the second value in the second register when handshaking is established. A computer program executed in the communication device,
In the computer that the communication device has,
Master mode setting command processing for setting the communication control means as a master mode for communicating with other communication devices using the communication device as a master;
Handshaking start instruction processing for setting the first value in the first register when the master mode is set for the communication control means;
Slave mode setting command processing for setting the communication control means slave mode for communicating with the other communication device as the communication device as a slave,
Said second register to said second value is not set period, met duration or time interval for exchanging all the master mode setting command process and the slave mode setting command processes the handshaking message And a switching process that is alternately performed at random time intervals determined based on random numbers .

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