JP4584106B2 - Network monitoring device - Google Patents

Description

  The present invention relates to a network monitoring apparatus that monitors whether or not a minimum interval time between frames is satisfied and detects an abnormality in, for example, Ethernet (registered trademark).

  In the field of Ethernet, according to the standard IEEE 802.3, at each interface (10BASE-T, 100BASE-TX, 1000BASE-T, etc.), the minimum interval time between packets (IFG: inter-frame gap, or IPG: (It may be defined as an inter-packet gap). Each manufacturer actively develops new LSIs with the rise of GEPON (Gigabit Ethernet Passive Optical Network). On the other hand, in order to realize independent monitoring of the Ethernet network, the minimum interval bandwidth of this IFG is used. Development is underway to transmit control signals.

  Conventionally, there has been a device for detecting the presence or absence of collision in a transmission path by arbitrarily changing the IFG length and transmitting (see, for example, Patent Document 1). In addition, there has been a device that considers a delay time considering the time of a transmission path and IFG, and waits for a response as a result (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 10-13465 Special table 2000-512456 gazette

By the way, some of the communication devices outflow the devices whose IFG length defined in the above-mentioned IEEE 802.3 does not satisfy the minimum interval condition. Yes. The condition that the IFG length becomes the minimum interval is difficult to reproduce in the existing network, so the reproducibility is low, and this trouble takes a very long time to isolate the cause.
In addition, the techniques described in Patent Documents 1 and 2 cannot be applied to such an IFG length abnormality detection.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a network monitoring apparatus that can easily detect an abnormality in a frame interval time in a network signal.

Network monitoring apparatus according to the present invention, a frame for monitoring the control signals flowing whether to satisfy the minimum time interval of a frame corresponding to the network signal is determined by the physical interface unit to determine the interface type of network signal interface An interval time monitoring unit is provided.

The network monitoring apparatus of the present invention monitors whether or not the frame interval time corresponding to the network signal satisfies a predetermined minimum interval time by the control signal flowing through the interface. It is possible to obtain a network monitoring device that can easily detect an abnormality in time.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a network monitoring apparatus according to Embodiment 1 of the present invention. Prior to this description, the network apparatus as a premise of the present invention will be described.
FIG. 2 is a block diagram of such a network device.
In FIG. 2, an Ethernet device 2 and a counter Ethernet device 3 are connected to the Ethernet transmission line 1. The Ethernet transmission line 1 is a known Ethernet transmission line such as 10BASE-T, 100BASE-TX, or 1000BASE-T. The Ethernet device 2 is a device that communicates with the opposing Ethernet device 3 via the Ethernet transmission path 1, and includes a transceiver 4, a physical interface unit (PHY) 5, an Ethernet control LSI 6, a transmission interface 7, and a reception interface 8. .

  The transceiver 4 includes a physical connector (RJ-45) and a transformer, and transmits and receives signals to and from the Ethernet transmission path 1 in the Ethernet device 2. The physical interface unit 5 exchanges information of an I / F type that can be handled with the opposite Ethernet device 3 connected via the Ethernet transmission path 1, and 10BASE-T and 100BASE-T defined by IEEE802.3. Connection is executed with an I / F such as TX or 1000BASE-T. That is, the physical interface unit 5 performs electrical termination of the network signal and sends a frame from the medium access control unit 9 described later as a network signal.

  The Ethernet control LSI 6 includes a medium access control unit 9 and controls the medium access control unit 9. The medium access control unit 9 transmits and receives MAC frames to and from the physical interface unit 5 via the transmission interface 7 and the reception interface 8. The transmission interface 7 is MII (Media Independent Interface) _TX I / F or GMII (Gigabit Media Independent Interface) _TX I / F, and the reception interface 8 is MII_RX I / F or GMII_RXI / F.

In the network device configured as described above, first, the operation of the reception processing from the Ethernet transmission line 1 in the Ethernet device 2 will be described.
The physical interface unit 5 executes an appropriate process defined by IEEE 802.3 in accordance with the I / F condition on the Ethernet transmission path 1 and extracts a control code pattern between the IFG pattern and the physical interface unit 5. . After extracting the IFG pattern and control code, the physical interface unit 5 performs code conversion on the data to be transmitted to the medium access control unit 9, and standardized transmission of MII_TX I / F or GMII_TX I / F The data is converted into a parallel number, and data, a clock, and a control signal are transmitted to the medium access control unit 9.

  When data is transmitted to the Ethernet transmission line 1, the data to be transmitted from the medium access control unit 9 is matched with the I / F condition on the Ethernet transmission line 1 determined by the physical interface unit 5, and MII_RX or Transmission data parallel conversion standardized with respect to the GMII_RX I / F is performed, and data, a clock, and a control signal are transmitted to the physical interface unit 5. The physical interface unit 5 performs appropriate processing defined by IEEE 802.3 on the data transmitted from the medium access control unit 9 and transmits the data to the Ethernet transmission line 1. At this time, if no data is transmitted from the medium access control unit 9, the physical interface unit 5 transmits the IFG code to the Ethernet transmission path 1.

  In the general form described above, when the IFG does not enter the Ethernet transmission line 1 at an appropriate interval, the medium access control unit 9 cannot normally process the data received via the MII / GMII_RX I / F. There is. Conversely, when data is transmitted from the medium access control unit 9 via the MII / GMII_TX I / F, the MII / s transmitted by the medium access control unit 9 is necessary for the physical interface unit 5 to transmit an appropriate IFG to the opposite device. In GMII_TX I / F, it is necessary to guarantee a data interval at which an appropriate IFG can be inserted into the physical interface unit 5. Therefore, in the present embodiment, such a frame interval time monitoring unit for monitoring IFG is provided, which will be described below with reference to FIG.

  In FIG. 1, the transceiver 4 to the medium access control unit 9 are the same as the respective components in FIG. 2, and thus description thereof is omitted here. The TX IFG detection circuit 11 and the RX IFG detection circuit 12 constitute a frame interval time monitoring unit that monitors whether the frame interval time satisfies a predetermined minimum interval time based on the invalid data width on the interface. The TX IFG detection circuit 11 monitors the frame interval time based on the invalid data width on the transmission interface 7 from the medium access control unit 9 to the physical interface unit 5, and the RX IFG detection circuit 12 The frame interval time is monitored based on the invalid data width on the reception interface 8 from the control unit 9 to the physical interface unit 5. The TX IFG detection circuit 11 and the RX IFG detection circuit 12 constantly monitor and check whether the IFG to be transmitted or the IFG to be received can ensure the expected IFG interval, to ensure the quality of the Ethernet transmission line 1 and It monitors whether the IFG control of the new Ethernet control LSI 6 is normally performed. If the IFG to be transmitted or received does not secure the expected IFG interval, an alarm is raised.

Next, the operation of the present embodiment will be described.
A signal coming from the Ethernet transmission line 1 is extracted by the physical interface unit 5 and IFG is extracted, and data is transmitted to the transmission interface 7 (MII_TX I / F or GMII_TX I / F). Here, whether to use the MII_TX I / F or the GMII_TX I / F is determined on the Ethernet transmission line 1 according to which I / F defined by the opposing Ethernet device 3 and IEEE 802.3 is connected. In 10BASE-T and 100BASE-T, the MII I / F is adopted, and the I / F configuration defined in IEEE 802.3 defined in FIG. Further, when connecting with 1000BASE-T, the GMII I / F defined in FIG. 3B is applied.

  Whether the MII I / F is applied, the GMII I / F is applied, or the MII I / F, whether the 10BASE-T or 100BASE-TX is determined is recognized by the physical interface unit 5, and this information is detected by TX IFG. Notify the circuit 11 and the RX IFG detection circuit 12. Thereby, the TX IFG detection circuit 11 and the RX IFG detection circuit 12 determine which I / F how to perform IFG detection.

Hereinafter, the operation of the TX IFG detection circuit 11 (IFG_TX interval abnormality detection) will be described.
The IFG_TX interval abnormality detection is realized by monitoring the interval from the transmission data end point of the TX valid data transmitted from the medium access control unit 9 to the physical interface unit 5 to the start point of the next TX valid data.

  In the MII I / F defined in FIG. 3A, the MII_TX portion includes four parallel data TXD [3. . 0], TXCLK for controlling the transmission timing of this signal, TXEN indicating that this signal is valid, and TXER indicating that this signal is abnormal. The COL signal and the CRS signal are not used particularly in the IFG detection circuit.

  The TX IFG detection circuit 11 recognizes which mode of connection in 10BASE-T, 100BASE-TX, or 1000BASE-T from the information of which I / F the Ethernet transmission line 1 is connected to from the physical interface unit 5. be able to. Hereinafter, the case where it connects by 10BASE-T is demonstrated as an example.

  When connected by 10BASE-T, TXCLK becomes a 2.5 MHz clock, and four parallel signals are transmitted at a speed of 2.5 MHz. By operating 4 parallel data at 2.5 MHz, a data transfer rate of 10 MHz is realized. Here, MEN_TX I / F is always valid for TXEN when valid data is transmitted. As a result, when TXEN is invalid, it counts how many times TXCLK operates continuously in 2.5 MHZ, and multiplies the counted number of clocks by the reciprocal number (400 ns) of 2.5 MHz of one clock, Free time between data can be calculated. Since the physical interface unit 5 performs an operation of inserting an IFG into the Ethernet transmission line 1 for this data free time, the medium access control unit 9 always uses 12 bytes defined by 10BASE-T in IEEE 802.3 when it is normal. It is necessary to guarantee the physical interface unit 5 with an interval of (9.6 μsec) or more from the end of the valid data to the start of the next valid data. For this reason, it is possible to detect that an IFG abnormality has occurred on the TX side by making the condition that the count value of TXCLK is less than 24 counts.

  FIG. 4 shows a timing chart when the IFG is normal and when the IFG is abnormal in the 10BASE-T MII_TX I / F. In addition, (a) is a case where IFG is normal, (b) is a case where IFG is abnormal.

  Similarly, the MII I / F is adopted in 100BASE-TX, but the operation speed of TXCLK at this time is 25 MHz. The detection method is to calculate the IFG time from the clock count when TXEN is invalid as in 10BASE-T. However, in IEEE802.3, a clear minimum IFG time is not defined in 100BASE-TX. Generally, 12 bytes (0.96 μsec) are defined, and detection is possible by changing the count number of the 25 MHz clock.

Next, IFG_TX abnormality detection when the Ethernet transmission line 1 operates at 1000BASE-T will be described.
In the GMII I / F defined in FIG. 3B, the GMII_TX portion includes eight parallel data TXD [7. . 0], GTXCLK for controlling the transmission timing of this signal, TXEN indicating that this signal is valid, and TXER indicating that this signal is abnormal. Note that the COL signal and the CRS signal are not used particularly in the IFG detection circuit, and a detailed description thereof will be omitted.

  The TX IFG detection circuit 11 can recognize in which mode of 10BASE-T, 100BASE-TX, or 1000BASE-T the Ethernet transmission line 1 is connected as described in the MII I / F.

  In the case of 1000BASE-T, GTXCLK becomes a 125 MHz clock, and eight parallel signals are transmitted at a speed of 125 MHz. A data transfer rate of 1 Gbps is realized by operating eight parallel data at 125 MHz. Here, GMII_TX I / F is always valid for TXEN when valid data is transmitted. This counts how many times TXCLK operates continuously at 125 MHz when TXEN is disabled, and the free time between data is obtained by multiplying the counted number of clocks by the reciprocal (8 ns) of 125 MHz of one clock. Can be calculated.

  Since the physical interface unit 5 performs an operation of inserting an IFG into the Ethernet transmission line 1 with respect to this data free time, the medium access control unit 9 must always use 8 bytes (8 bytes (1000BASE-T) defined by IEEE 802.3 when normal. It is necessary to guarantee the physical interface unit 5 with an interval of 0.064 μsec) or more from the end of the valid data to the start of the next valid data. Therefore, when the count value of TXCLK is less than 8, it is possible to detect that an IFG abnormality has occurred on the TX side. Further, since there is also a medium access control unit 9 that is normally designed to guarantee an IFG interval of 12 bytes, it is possible to change the IFG interval abnormality detection time in units of 8 ns by changing the clock count value.

Next, operation of the RX IFG detection circuit 12 (IFG_RX interval abnormality detection) will be described.
IFG_RX interval abnormality detection is realized by monitoring the interval from the transmission data end point of the RX valid data transmitted from the physical interface unit 5 to the medium access control unit 9 to the start point of the next RX valid data.

  In the Ethernet transmission line 1, the I / F to be connected is determined by the 10 BASE-T detected by the physical interface unit 5 as described above because the TX unit and the RX unit always apply the same I / F. Alternatively, MII_RX I / F or GMII_RX I / F is applied based on information of 100BASE-TX and 1000BASE-T. The method for detecting IFG_RX is the same as the method for detecting IFG_TX.

  The case where the MII_RX I / F operates at 10BASE-T will be described. The MII_RX part in the MII I / F defined in FIG. 3A includes four parallel data RXD [3. . 0], RXCLK for controlling the transmission timing of this signal, RXDV indicating that this signal is valid, and RXER indicating that this signal is abnormal. Like the TX unit, RXCLK operates at 2.5 MHz, and four parallel data operate at 2.5 MHz, thereby realizing a data transfer rate of 10 MHz. Here, when the MII_RX I / F transmits valid data from the physical interface unit 5 to the medium access control unit 9, RXDV becomes valid.

  As a result, when RXDV is disabled, the number of consecutive RXMHZ operations of RXCLK is counted and the number of clocks counted is multiplied by the reciprocal (400 ns) of 2.5 MHz for one clock. The idle time can be calculated. The IFG interval time detected here is the IFG time that the opposing Ethernet device 3 transmits to the Ethernet transmission line 1. In 10BASE-T, the interval of 12 bytes (9.6 μsec) or more is required from the end of the valid data to the beginning of the next valid data, as in IFG_TX. If the condition is less than 24, it is possible to detect that an IFG abnormality has occurred on the RX side.

  Similarly, in 100BASE-T and 1000BASE-T, it is possible to detect an abnormality that does not satisfy the minimum IFG interval defined by each I / F by counting RXCLK when the RXDV signal is invalid instead of the TXEN signal. .

  In the above embodiment, the case where the IFG length in Ethernet is monitored has been described. However, even in other networks, the minimum interval time is defined in advance between the packets. If applicable, it is equally applicable.

  As described above, according to the network monitoring apparatus of the first embodiment, the physical interface unit that determines the interface type of the network signal, the medium access control unit that transmits and receives frame data, the physical interface unit, and the medium access control unit Since the network interface is provided with an interface through which frame data is connected and a frame interval time monitoring unit that monitors whether or not the minimum time interval of the frame corresponding to the network signal determined by the physical interface unit is satisfied. It is possible to easily detect an abnormality in the frame interval time. As a result, the quality of the network can be improved.

  Further, according to the network monitoring apparatus of the first embodiment, the frame interval time monitoring unit monitors the frame interval time based on the invalid data width on the transmission interface from the medium access control unit to the physical interface unit. Therefore, it is possible to easily determine whether there is an abnormality in the frame interval time on the transmission side, for example, whether the IFG control of the new Ethernet control LSI is normally performed.

  Further, according to the network monitoring apparatus of the first embodiment, the frame interval time monitoring unit monitors the frame interval time based on the invalid data width on the reception interface from the physical interface unit to the medium access control unit. Therefore, even if there is a communication device that does not meet the minimum frame interval time among the communication devices connected to the network, this can be easily known. When trouble occurs due to not satisfying, the cause can be easily identified.

It is a block diagram which shows the network monitoring apparatus by Embodiment 1 of this invention. It is a block diagram which shows the network apparatus used as the premise of the network monitoring apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows MII I / F and GMII I / F in Embodiment 1 of this invention. It is a timing chart at the time of IFG normality and IFG abnormality in Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ethernet transmission line, 5 Physical interface part, 7 Transmission interface, 8 Reception interface, 9 Medium access control part, 10 Ethernet apparatus, 11 TX IFG detection circuit, 12 RX IFG detection circuit

Claims (4)

A physical interface unit to determine the interface type of the network signals,
A medium access control unit for transmitting and receiving a control signal indicating data validity and data obtained by parallel conversion of the network signal based on the interface type determined by the physical interface unit ;
Connecting the physical interface unit and the medium access control unit, and an interface through which the data and the control signal flow;
Network monitoring comprising: a frame interval time monitoring unit that monitors whether or not the network signal satisfies a minimum time interval of a frame corresponding to the interface type determined by the physical interface unit, by a control signal flowing through the interface apparatus. 2. The network monitoring apparatus according to claim 1, wherein the frame interval time monitoring unit monitors the frame interval time based on an invalid time of the control signal on the transmission interface from the medium access control unit to the physical interface unit. . Frame interval time monitoring unit, the physical interface unit based on the dead time of the control signal on the receive interface to the medium access control unit from claim 1 Symbol placement of network monitoring, wherein the monitoring the frame interval time apparatus. The frame interval time monitoring unit uses a clock that is determined based on the interface type determined by the physical interface unit and flows through the interface, and determines the invalid time of the control signal according to the count number of the clock when the control signal is invalid. The network monitoring device according to claim 2 or 3, wherein the network monitoring device is obtained.

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