JP2010239418A - Transmission line terminating circuit and transmission line monitoring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To implement a function for monitoring a message on a transmission line, without reducing throughput, in a transmission line terminating circuit of a radio base station device for mobile communication connected to a host device via an IP transmission line. <P>SOLUTION: In a transmission line terminating circuit of a radio base station device for mobile communication, an electrical signal (MII) between PHY and MAC is branched and a message on a transmission line is outputted in real time via a transmitting monitor PHY and a receiving monitor PHY. Since the message is outputted without going via MAC, a processing for copying the message by a higher layer (processor or the like) of MAC is not required and throughput is not reduced. Furthermore, since no MAC is required for monitoring, finite global MAC addresses are not wasted. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a configuration of a transmission line termination circuit using an IP transmission line, and more particularly, to a transmission line termination circuit mounted in a mobile communication radio base station apparatus or other electronic apparatus.

  In mobile communication systems, the introduction of IP networks is progressing toward the next generation (fourth generation), and ETHERNET (registered trademark) is adopted for the transmission path between the host device and other radio base station devices in the radio base station device. is doing. With the diversification of transmission paths in mobile communication systems and the increase in traffic on the transmission paths, it has become necessary for operators to monitor messages on transmission paths in order to analyze failures in mobile communication systems.

  However, in the conventional apparatus, in order to realize an IP transmission line monitoring function such as ETHERNET, a process of copying a message by a MAC upper layer (processor or the like) is prepared with a plurality of MAC function units. Had to be implemented. For this reason, the conventional apparatus has a problem of a decrease in processing capability due to the copy process. In addition, since the monitor circuit has a configuration capable of LAN connection, a global MAC address must be prepared for monitoring.

  Patent Documents 1 and 2 are listed as documents describing related technologies related to the present invention. Patent Document 1 describes that a “bus switching unit” is provided between a physical layer and a data link layer in an IP transmission device (for example, from the lower left of the second page to the upper right of the third page). Further, Patent Document 2 describes that a branch circuit is provided in a line input / output portion in a data communication system to trace input / output data to be input / output, and monitor the trace result display or color (for example, paragraphs). 0009-0011).

Japanese Patent Laid-Open No. 03-057345 Japanese Patent Laid-Open No. 05-014451

  A conventional configuration will be described with reference to FIG.

  The transmission line termination circuit unit includes a physical termination unit 81, a PHY 84, and a MAC 87. The physical termination unit 81 performs physical termination on the network side (IP transmission path), and includes a transformer, a small form factor pluggable (hereinafter, SFP) module, and the like. The physical termination unit 81 and the PHY 84 are connected by an electrical signal. Hereinafter, a reception signal from the network side to the PHY 84 is referred to as network side reception data, and a transmission signal from the PHY 84 to the network side is referred to as network side transmission data. The PHY 84 is a device that terminates the first layer (physical layer) of the OSI reference model, and has a function of converting a signal of the physical layer to a lower sublayer (MAC layer) of the second layer of the OSI reference model. The PHY 84 and the MAC 87 are connected by Media Independent Interface (hereinafter referred to as MII). As described above, the MAC 87 corresponds to the lower sublayer (MAC layer) of the second layer of the OSI reference model, and functions to perform data conversion with the PHY 84, data transmission / reception method, error detection, etc., and upper layer processing. It has. Hereinafter, the MII interface from PHY 84 to MAC 87 is referred to as a reception MII interface, and the MII interface from MAC 87 to PHY 84 is referred to as a transmission MII interface.

  The monitor unit is a physical termination unit 82 (for reception monitoring), a physical termination unit 83 (for transmission monitoring), PHY85 (for reception monitoring), PHY86 (for transmission monitoring), MAC88 (for reception monitoring), and MAC89 (for transmission monitoring). Consists of The physical terminators 82 and 83 are transformers (including RJ45 connectors) and SFP modules as well as the physical terminator 81 of the transmission line termination circuit unit, but are not necessarily the same as the transmission line termination circuit unit. For example, the physical termination unit of the transmission path termination circuit unit may be an optical line, and the physical termination unit of the monitor unit may be a transformer. PHY85 and PHY86 are devices that terminate the first layer (physical layer) of the OSI reference model, like PHY84. The PHY 85 is connected to the physical termination unit 82 to realize a reception monitor function, and the PHY 86 is connected to the physical termination unit 83 to realize a transmission monitor function. The MACs 88 and 89 correspond to the lower sublayer (MAC layer) of the second layer of the OSI reference model, and receive data and transmission data copied in the upper layer are received to the PHY 85, and are transmitted to the PHY 86. Relaying. Hereinafter, MAC88 to PHY85 are referred to as a reception monitor transmission MII interface, and MAC89 to PHY86 are referred to as a transmission monitor transmission MII interface.

  A conventional operation will be described with reference to FIG. In order to explain the conventional operation in an easy-to-understand manner, it is described separately for the receiving side and the transmitting side.

  First, the operation on the receiving side will be described. Data from the network side (IP transmission line) is received by the physical termination unit 81 of the transmission line termination circuit unit. The network-side received data received via the physical termination unit 81 is input to the PHY 84 and converted into a reception MII interface. The reception MII interface is converted by the MAC 87 from the reception MII interface into reception data that can be processed in an upper layer. When the upper layer receives the reception data, it performs a copy process as transmission data to the reception monitoring MAC 88. The MAC 88 converts the received copy data into a reception monitoring transmission MII interface. The reception monitor transmission MII interface is input to the PHY 85 and converted into reception monitor transmission data. The reception monitor transmission data is output from the reception monitor via the physical termination unit 82.

  Next, the operation on the transmission side will be described. The upper layer sends the transmission data to the MAC 87 on the network side and performs a copy process as transmission data to the MAC 89 on the monitor side. Transmission data on the network side is converted by the MAC 87 into a transmission MII interface, and transmission data on the monitor side is converted by the MAC 89 into a transmission MII interface for transmission monitoring. The transmission MII interface on the network side is input to the PHY 84 and converted from the transmission MII interface to network side transmission data. The network side transmission data is output to the network side (IP transmission path) via the physical termination unit 81. On the other hand, the transmission monitor transmission MII interface on the transmission monitor side is input to the PHY 86 and converted into transmission monitor transmission data. Transmission data for transmission monitoring is output from the transmission monitor via the physical termination unit 83. Similar to the physical termination unit 81, the physical termination unit 83 becomes an RJ45 connector and a transformer if the monitoring interface is a twisted pair line, and an SFP module if the monitoring interface is an optical line.

  As described above, conventionally, a dedicated MAC has been prepared to realize the monitor function. For this reason, data copy processing to the monitor interface has to be performed in an upper layer (mainly processed by the processor) of the MAC, which affects the processing capability. Also, since the monitor unit has a MAC, connection to a LAN or the like is possible, but a global MAC address must be acquired for monitoring, and a limited global MAC address is wasted.

  Therefore, in view of the above circumstances, the present invention provides a function for monitoring a message on a transmission line in a transmission line termination circuit of a mobile communication radio base station apparatus connected to a higher-level device via an IP transmission line. It aims to be realized.

  In order to achieve the above object, the present invention provides a transmission line termination circuit connected to a host device via an IP transmission line, a MAC connected to the host device, a PHY connected to the IP transmission line, Branch means for branching an electrical signal between the MAC and the PHY, and a monitoring PHY to which the electrical signal branched by the branch means is connected.

  The transmission path monitoring method according to the present invention is a transmission path monitoring method for monitoring a message on the IP transmission path using a transmission path termination circuit connected to the host apparatus via the IP transmission path. Branch an electrical signal between a MAC connected to a device and a PHY connected to the IP transmission path, connect a monitoring PHY to the branched electrical signal, and send the electrical signal to the monitor transmission data by the monitoring PHY It is characterized by being converted into.

  According to the present invention, in a transmission line termination circuit of a mobile communication radio base station apparatus connected to a host device via an IP transmission line, a function for monitoring a message on the transmission line can be realized without a reduction in processing capability. It becomes possible.

It is a block diagram which shows the structure of embodiment by this invention. It is a block diagram which shows the structure of other embodiment by this invention. It is a block diagram which shows the structure of a prior art.

  Hereinafter, the present invention will be described in detail by embodiments.

  In the embodiment described below, an electrical signal (MII) between a PHY and a MAC is branched in a transmission line termination circuit of a mobile communication radio base station apparatus, and is transmitted on the transmission line via a transmission monitor PHY and a reception monitor PHY. The message is output in real time. Since the message is output without going through the MAC, the process of copying the message by the upper layer (processor or the like) of the MAC becomes unnecessary, and the processing capability is not lowered. Further, since the configuration does not require a MAC for monitoring, a limited global MAC address is not used wastefully.

  That is, the IP transmission path monitoring circuit described below has a function of monitoring messages on a transmission path in a transmission path termination circuit of a mobile communication radio base station apparatus connected to a host device via an ETHERNET (IP transmission path). This is achieved without a reduction in processing capability and without adding a global MAC address. A specific configuration and operation will be described below.

  The configuration of this embodiment will be described with reference to FIG.

  As shown in FIG. 1, the IP transmission path monitoring circuit of the radio base station apparatus is roughly divided into two, a transmission path termination circuit section and a monitoring section.

  The transmission line termination circuit unit includes a physical termination unit 1, PHY4, and MAC7. The physical termination unit 1 performs physical termination on the network side (IP transmission path), and includes a transformer, an SFP module, and the like. When the network side is a twisted pair line (10Base-T, 100Base-TX, 1000Base-T), it is terminated by a transformer via an RJ45 connector, and when the network side is an optical line (1000Base-SX, 1000Base-LX), it is terminated by an SFP module. .

  The physical termination unit 1 and the PHY 4 are connected by an electric signal. When the network side is a twisted pair line, the electrical signal is transformed by a transformer (actually, there are many times the same), and when the network side is an optical line, the electrical signal is photoelectrically converted by the SFP module. Hereinafter, a reception signal from the network side to PHY4 is referred to as network side reception data, and a transmission signal from PHY4 to the network side is referred to as network side transmission data.

  PHY4 is a device that terminates the first layer (physical layer) of the OSI reference model, and has a function of converting a signal of the physical layer to a lower sublayer (MAC layer) of the second layer of the OSI reference model.

  PHY4 and MAC7 are connected by MII. MII has a plurality of forms (MII, SMII, RMII, GMII, SGMII, RGMII, etc.) depending on the speed of the transmission path (10Base, 100Base, 1000Base) and the type of PHY.

  As described above, the MAC 7 corresponds to the lower sub-layer (MAC layer) of the second layer of the OSI reference model, and functions to perform transmission / reception methods of PHY 4 and data, error detection, and data conversion processed by the upper layer It has. The MAC 7 may be configured as a single device or incorporated in an integrated device such as a processor. Hereinafter, the MII interface from PHY4 to MAC7 is referred to as a reception MII interface, and the MII interface from MAC7 to PHY4 is referred to as a transmission MII interface.

  The monitor unit includes a physical termination unit 2 (for reception monitoring), a physical termination unit 3 (for transmission monitoring), PHY5 (for reception monitoring), PHY6 (for transmission monitoring), and a conversion unit 11. The physical termination units 2 and 3 are transformers (including RJ45 connectors) and SFP modules as well as the physical termination unit 1 of the transmission line termination circuit unit, but are not necessarily the same as the transmission line termination circuit unit. For example, the physical termination unit of the transmission path termination circuit unit may be an optical line, and the physical termination unit of the monitor unit may be a transformer.

  PHY5 and PHY6 are devices that terminate the first layer (physical layer) of the OSI reference model, similarly to PHY4. The PHY 5 is connected to the physical termination unit 2 to realize a reception monitor function, and the PHY 6 is connected to the physical termination unit 3 to realize a transmission monitor function.

  The conversion unit 11 has a function of converting the reception MII interface of the transmission line termination circuit unit into a reception monitor transmission MII interface for the PHY 5 to transmit. Hereinafter, transmission data from PHY 5 to the reception monitor will be referred to as reception monitor transmission data, and transmission data from PHY 6 to the transmission monitor will be referred to as transmission monitor transmission data.

  The operation of this embodiment will be described with reference to FIG. In order to explain the operation of the present embodiment in an easy-to-understand manner, it is described separately on the reception side and the transmission side.

  First, the operation on the receiving side will be described. Data from the network side (IP transmission line) is received by the physical termination unit 1 of the transmission line termination circuit unit. When the IP transmission path is a twisted pair line (10Base-T, 100Base-TX, 1000Base-T), the physical termination unit 1 is terminated by a transformer via an RJ45 connector, and converts received data into a voltage. When the IP transmission path is an optical line (1000Base-SX, 1000Base-LX), the physical termination unit 1 is terminated by the SFP module, and the received data is converted from an optical signal to an electrical signal.

  The network-side received data received via the physical termination unit 1 is input to the PHY 4 that terminates the first layer (physical layer) of the OSI reference model, and converted into a reception MII interface.

  The MII interface is a PHY-MAC communication means standardized by IEEE 802.3, and includes a transmission MII interface and a reception MII interface. Normally, the MII interface is connected one-to-one with the PHY-MAC, but in this embodiment, in order to realize the monitor function, the MII interface is branched into two layers, the upper layer side and the monitor side. Accordingly, the reception MII interface converted by the PHY 4 branches to the MAC 7 on the higher layer side and the conversion unit 11 on the reception monitor side.

  The reception MII interface branched to the upper layer side is converted by the MAC 7 from the reception MII interface into reception data that can be processed by the upper layer. On the other hand, the reception MII interface branched to the reception monitor side is connected to the conversion unit 11.

  In order to realize the reception monitor, the reception MII interface needs to be converted into a reception monitor transmission MII interface so that the PHY 5 on the reception monitor side can transmit. The conversion from the reception MII interface to the reception monitor transmission MII interface in the conversion unit 11 is accompanied by a signal connection change or a data format change according to the specifications of the MII interface to be used.

  The reception monitor transmission MII interface converted by the conversion unit 11 is input to the PHY 5 and converted into reception monitor transmission data. Transmission data for reception monitoring is output from the reception monitor via the physical termination unit 2. Similar to the physical termination unit 1, the physical termination unit 2 is an RJ45 connector and a transformer if the monitoring interface is a twisted pair line, and an SFP module if the monitoring interface is an optical line.

  Next, the operation on the transmission side will be described. Transmission data from the upper layer is converted by the MAC 7 into a transmission MII interface. Similarly to the reception MII interface, the transmission MII interface branches into two, the network side and the monitor side. Accordingly, the transmission MII interface converted by the MAC 7 branches to PHY 4 on the network side and PHY 6 on the transmission monitor side.

  The transmission MII interface branched to the network side is input to the PHY 4 and converted from the transmission MII interface to network side transmission data. The network side transmission data is output to the network side (IP transmission path) via the physical termination unit 1.

  On the other hand, the transmission MII interface branched to the transmission monitor side is input to the PHY 6 and converted into transmission data for transmission monitoring. Since the transmission MII interface is originally an interface capable of transmitting PHY, it does not need to be converted into a transmission interface like the reception MII interface, and is connected to the PHY 6 as it is.

  Transmission data for transmission monitoring is output from the transmission monitor via the physical termination unit 3. As with the physical termination unit 1, the physical termination unit 3 is an RJ45 connector and a transformer if the monitoring interface is a twisted pair line, and an SFP module if the monitoring interface is an optical line.

  Here, a supplementary description will be given of the monitor function of the present embodiment. The physical termination units 2 and 3 of the monitor unit are not necessarily the same interface as the physical termination unit 1 of the transmission line circuit unit. For example, the network side (IP transmission line) may be an optical line, and the monitor side may be an RJ45 connector and a transformer. The connection destination of the monitor unit is not intended for a network such as a LAN, but is assumed to be a measuring instrument such as a data analyzer or a personal computer that can analyze an ETHERNET frame. Therefore, in this embodiment, the interface of the monitor unit is configured to be compatible with either a twisted pair line or an optical line.

  In addition, since the monitor function is considered to be intended for failure analysis in the network, it is not normally used by connecting to a network such as a LAN. Therefore, since it is not necessary to prepare a global MAC address in the monitor unit, in this embodiment, the monitor function is realized by branching the PHY-MAC MII interface.

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

  The first effect is that the processing capability does not decrease even if the monitor function is provided. The reason is that the MII interface between the PHY and MAC is branched to output a message without using the MAC by realizing the monitoring function, so that the message copy process from the MAC to the monitoring MAC is no longer necessary. is there.

  The second effect is that the global MAC address can be effectively used. The reason is that the connection destination of the monitor is limited to the measuring instrument and the personal computer, and therefore the MAC is unnecessary on the monitor side in the circuit configuration.

  The third effect is that the real-time property of the transmission line monitor is increased accompanying the first effect. The reason is that the monitoring method without using the MAC is realized, and the data copy process by the upper layer of the MAC is eliminated, so that the output delay due to the copy process is eliminated. As a result, a message that is actually being communicated can be monitored with a very slight delay (PHY output delay).

  The configuration of another embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 2, in this embodiment, the IP transmission path monitor circuit of the radio base station apparatus is roughly divided into two, a transmission path termination circuit section and a monitor section.

  The transmission line termination circuit unit includes a physical termination unit 51, a PHY 54, a MAC 57, and a connector 60. The physical termination unit 51 performs physical termination on the network side (IP transmission path), and includes a transformer, an SFP module, and the like. The physical termination unit 51 and the PHY 54 are connected by an electrical signal. Hereinafter, a reception signal from the network side to the PHY 54 is referred to as network side reception data, and a transmission signal from the PHY 54 to the network side is referred to as network side transmission data.

  The PHY 54 is a device that terminates the first layer (physical layer) of the OSI reference model, and has a function of converting a signal of the physical layer to a lower sublayer (MAC layer) of the second layer of the OSI reference model. The PHY 54 and the MAC 57 are connected by MII. As described above, the MAC 57 corresponds to the lower sublayer (MAC layer) of the second layer of the OSI reference model, and functions to perform transmission / reception methods of data with the PHY 54, error detection, etc., and data conversion processed by the upper layer. It has. Hereinafter, the MII interface from the PHY 54 to the MAC 57 is referred to as a reception MII interface, and the MII interface from the MAC 57 to the PHY 54 is referred to as a transmission MII interface.

  The connector 60 is for connecting the transmission line termination circuit unit and the monitor unit, and has a hot-swap specification so that the monitor unit can be attached and detached even when the transmission line termination circuit unit is powered on. Yes.

  The monitor unit includes a physical termination unit 52 (for reception monitoring), a physical termination unit 53 (for transmission monitoring), a PHY 55 (for reception monitoring), a PHY 56 (for transmission monitoring), a connector 60, and a conversion unit 61. The physical termination units 52 and 53 are transformers (including RJ45 connectors) and SFP modules as in the physical termination unit 51 of the transmission line termination circuit unit, but are not necessarily the same as the transmission line termination circuit unit. For example, the physical termination unit of the transmission path termination circuit unit may be an optical line, and the physical termination unit of the monitor unit may be a transformer.

  The PHY 55 and the PHY 56 are devices that terminate the first layer (physical layer) of the OSI reference model, like the PHY 54. The PHY 55 is connected to the physical termination unit 52 to realize a reception monitor function, and the PHY 56 is connected to the physical termination unit 53 to realize a transmission monitor function.

  The conversion unit 61 has a function of converting the reception MII interface of the transmission line termination circuit unit into a reception monitor transmission MII interface for the PHY 55 to transmit. Hereinafter, transmission data from the PHY 55 to the reception monitor is referred to as reception monitor transmission data, and transmission data from the PHY 56 to the transmission monitor is referred to as transmission monitor transmission data.

  Similarly to the transmission line termination circuit unit, the monitor unit also has a connector 60 corresponding to the hot-swap specification, and not only the connection of the reception MII interface but also the transmission MII interface of the transmission line termination circuit unit and the transmission MII interface of PHY6. Connecting.

  The operation of this embodiment will be described with reference to FIG. In order to explain the operation of the present embodiment in an easy-to-understand manner, it is described separately on the reception side and the transmission side.

  First, the operation on the receiving side will be described. Data from the network side (IP transmission line) is received by the physical termination unit 51 of the transmission line termination circuit unit. The network-side received data received via the physical termination unit 51 is input to the PHY 54 and converted into a reception MII interface.

  Normally, the MII interface is connected one-to-one with the PHY-MAC, but in this embodiment, in order to realize the monitor function, the MII interface is branched into two layers, the upper layer side and the monitor side. Accordingly, the reception MII interface converted by the PHY 54 branches to the MAC 57 on the upper layer side and the connector 60 on the reception monitor side.

  The reception MII interface branched to the upper layer side is converted by the MAC 57 from the reception MII interface into reception data that can be processed in the upper layer. On the other hand, the reception MII interface branched to the reception monitor side is connected to the conversion unit 61 via the connector 60.

  In order to realize the reception monitor, the reception MII interface needs to be converted into a reception monitor transmission MII interface so that the PHY 55 on the reception monitor side can transmit. The conversion from the reception MII interface to the reception monitor transmission MII interface in the conversion unit 61 involves a change in signal connection or a change in data format according to the specifications of the MII interface to be used. The reception monitor transmission MII interface converted by the conversion unit 61 is input to the PHY 55 and converted into reception monitor transmission data.

  The reception monitor transmission data is output from the reception monitor via the physical termination unit 52. Similar to the physical termination unit 51, the physical termination unit 52 becomes an RJ45 connector and a transformer if the monitoring interface is a twisted pair line, and an SFP module if the monitoring interface is an optical line.

  Next, the operation on the transmission side will be described. Transmission data from the upper layer is converted into a transmission MII interface by the MAC 57. Similarly to the reception MII interface, the transmission MII interface branches into two, the network side and the monitor side. Accordingly, the transmission MII interface converted by the MAC 57 branches to the PHY 54 on the network side and the connector 60 on the transmission monitor side.

  The transmission MII interface branched to the network side is input to the PHY 54 and converted from the transmission MII interface to network side transmission data. The network side transmission data is output to the network side (IP transmission path) via the physical termination unit 51.

  On the other hand, the transmission MII interface branched to the transmission monitor side is input to the PHY 56 via the connector 60 and converted into transmission data for transmission monitoring. Since the transmission MII interface is originally an interface capable of transmitting PHY, it does not need to be converted into a transmission interface like the reception MII interface, and is connected to the PHY 56 as it is.

  Transmission data for transmission monitoring is output from the transmission monitor via the physical termination unit 53. Similar to the physical termination unit 51, the physical termination unit 53 is an RJ45 connector and a transformer if the monitoring interface is a twisted pair line, and an SFP module if the monitoring interface is an optical line.

  Here, a supplementary description will be given of the monitoring function of another embodiment of the present invention. In another embodiment of the present invention, the transmission line circuit unit and the monitor unit are connected by a connector 60 that can be hot-plugged. For this reason, it is possible to isolate | separate a transmission line circuit part and a monitor part as needed. For example, since the monitor function is not used unless there is any failure in normal operation, it can be disconnected and attached later to perform analysis when a failure occurs. It is also possible to use a monitor unit that is attached to the interface according to the interface of the measuring instrument used for the monitor.

  In another embodiment of the present invention, since the monitor function can be separated, the following additional effect can be expected.

  The first additional effect is that the transmission line termination circuit can be provided at low cost. The reason is that the monitor part can be separated, so that the monitor part can be made optional, and whether or not the monitor part is purchased can be selected. If a monitor is not required for the initial operation, the monitor circuit need not be purchased. If failure analysis is required, only the monitor part needs to be purchased at that time.

  The second additional effect is that the power consumption of the transmission line termination circuit can be reduced. This is because the monitor unit can be separated. In operation, wasteful power consumption can be prevented by removing the monitor portion when the monitor is unnecessary.

1, 2, 3, 51, 52, 53, 81, 82, 83 Physical termination unit 4, 5, 6, 54, 55, 56, 84, 85, 86 PHY
7, 57, 87, 88, 89 MAC
11, 61 Converter 60 Connector

Claims (6)

A transmission line termination circuit connected to a host device via an IP transmission line,
A MAC connected to the host device;
PHY connected to the IP transmission path;
Branching means for branching an electrical signal between the MAC and the PHY;
A monitoring PHY to which the electrical signal branched by the branching unit is connected;
A transmission line termination circuit comprising: A monitor unit including the monitor PHY;
A connector for connecting the monitor PHY of the monitor unit to the branching means so as to be insertable / removable;
The transmission line termination circuit according to claim 1, further comprising: The branching unit includes a reception signal branching unit that branches a reception signal, and a transmission signal branching unit that branches a transmission signal,
3. The transmission line termination circuit according to claim 1, wherein there are two monitoring PHYs corresponding to the reception signal branching unit and the transmission signal branching unit, respectively.   Necessary changes are made between the PHY and the monitoring PHY corresponding to the reception signal branching means according to the specifications of the communication interface of the PHY and the monitoring PHY corresponding to the reception signal branching means. 4. The transmission line termination circuit according to claim 3, further comprising conversion means.   The monitoring PHY is branched by the branching means, and converts the electrical signal input to the monitoring PHY into transmission data for monitoring. The transmission line termination circuit described. A transmission path monitoring method for monitoring a message on the IP transmission path by using a transmission path termination circuit connected to the host device via the IP transmission path,
Branching an electrical signal between a MAC connected to the host device and a PHY connected to the IP transmission path;
Connect a monitor PHY to the branched electric signal,
A transmission path monitoring method, wherein the electrical signal is converted into monitor transmission data by the monitor PHY.

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