JP5056775B2 - Frame loss measurement method and measurement system, and network relay device - Google Patents

Description

  The present invention relates to a method for measuring a frame loss between relay devices, and more particularly, a frame loss measurement method and measurement system capable of accurately measuring a frame loss between relay devices connected by multipoint connection, and a network relay. It relates to equipment.

  As a method for measuring frame loss between network relay devices, ITU-T Y.T. There is a method using LMM (Loss Measurement Message) and LMR (Loss Measurement Reply) defined in 1731.

  As an example, a case where the frame loss between a pair of network relay devices A and B is measured using LMM and LMR will be described.

  As shown in FIG. 5, first, the LMM 1 is transmitted from the network relay device A that is the measurement subject to the network relay device B. At this time, the network relay device A writes the frame counter value (TxFCf) of the transmission counter in the counter field of the LMM 1 and transmits it.

  The network relay device B that has received LMM1 writes the frame counter value (referred to as RxFCf) of the reception counter at the time of receiving LMM1 to LMM1. Thereafter, the network relay device B converts LMM1 into LMR1, and transmits LMR1 to the network relay device A. At this time, the network relay device B writes the frame counter value of the transmission counter (referred to as TxFCb) in the counter field of LMR1 and transmits it.

  The network relay device A that has received the LMR1 stores the above three frame counter values (TxFCf, RxFCf, TxFCb) written in the LMR1 and the frame counter value (referred to as RxFCl) of the reception counter when the LMR1 is received. deep. In the case of FIG. 5, the frame counter values stored in the network relay device A are TxFCf = 1, RxFCf = 1, TxFCb = 2, and RxFCl = 2.

  Thereafter, the LMM2 is transmitted from the network relay device A to the network relay device B, and the frame counter values (TxFCf, RxFCf, TxFCb) and the LMR2 stored in the LMR2 are received as in the case of the LMM1 described above. The frame counter value (RxFC1) is stored in the network relay device A. In the case of FIG. 5, the frame counter values stored in the network relay device A are TxFCf = 15, RxFCf = 13, TxFCb = 8, and RxFCl = 6.

  Since the frame counter value TxFCf = 1 of the transmission counter at the time of LMM1 transmission and the frame counter value TxFCf = 15 of the transmission counter at the time of LMM2 transmission, the network relay is performed between the transmission of LMM1 and the transmission of LMM2. The number of frames transmitted from the device A to the network relay device B is 14.

  On the other hand, since the frame counter value RxFCf = 1 of the reception counter at the time of LMM1 reception and the frame counter value RxFCf = 13 of the reception counter at the time of LMM2 reception, the time from reception of LMM1 to reception of LMM2 In the meantime, the number of frames received by the network relay device B from the network relay device A is 12.

  Therefore, even though the network relay device A has transmitted 14 frames to the network relay device B, the network relay device B has received only 12 frames, and the network relay device A transmits a frame to the network relay device B. It can be seen that a frame loss of 14−12 = 2 occurs.

  Similarly, since the frame counter value TxFCb = 2 of the transmission counter at the time of LMR1 transmission and the frame counter value TxFCb = 8 of the transmission counter at the time of LMR2 transmission, between the transmission of LMR1 and the transmission of LMR2 The number of frames transmitted from the network relay device B to the network relay device A is six.

  On the other hand, since the frame counter value RxFC1 of the reception counter at the time of receiving the LMR1 is 2 and the frame counter value RxFC1 of the reception counter at the time of receiving the LMR2 is 6, the time between receiving the LMR1 and receiving the LMR2 The number of frames received from the network relay device B by the network relay device A is four. Therefore, it can be seen that a frame loss of 6-4 = 2 occurs when a frame is transmitted from the network relay device B to the network relay device A.

  As described above, by repeating the measurement of the frame counter value using the LMM and the LMR, the frame loss between the network relay devices A and B to be measured can be obtained from the difference between the frame counter values.

  The prior art document information related to the invention of this application includes the following.

JP 2008-244870 A

ITU-T Recommendation Y.E. 1731

  However, in the method using the above LMM and LMR, there is no problem when the network relay devices A and B to be measured are connected one-to-one (point-to-point connection), but the network relay device A to be measured , B are connected by multipoint connection (point-to-multipoint connection), a problem may occur.

  Specifically, as shown in FIG. 6 (a), if the network relay devices A and B to be measured and the network relay device C not to be measured are connected to the network 51 by multipoint connection, the network The frame from the relay device A does not necessarily pass through the network relay device B but may be transmitted to the network relay device C.

  When a frame is transmitted from the network relay device A to the network relay device C, the network relay device B does not receive the frame even though the frame is transmitted from the network relay device A. Although no loss has occurred, a frame loss has occurred between the network relay devices A and B.

  As shown in FIG. 6B, it is also conceivable that the network relay device A counts only the frames transmitted to the network relay device B. However, for example, when considering a case where a frame is transmitted from the network relay device A to the network relay device C, if another network relay device included in the network 51 has not yet learned the address of the network relay device C, the original network Even a frame addressed to the relay device C may be flooded by the network relay device B. In this case, the frame not counted by the network relay device A is received and counted by the network relay device B, and the frame loss between the network relay devices A and B becomes negative.

  In general, since it is difficult to know whether an arbitrary frame has been learned by all the network relay devices in the network 51 or not yet learned, an arbitrary frame transmitted from the network relay device A is converted to the network relay device B. It is difficult to determine whether or not to pass.

  Further, as shown in FIG. 6C, when there is a frame passing from the network relay device C that is not the measurement target to the network relay device B, the network relay device is not transmitted from the network relay device A. B is received and counted, and the frame loss between the network relay devices A and B is negative.

  Thus, when the network relay devices A and B to be measured are connected by multipoint connection, it is difficult to accurately measure the frame loss between the network relay devices A and B.

  Therefore, an object of the present invention is to solve the above-described problem and to obtain a frame loss that can accurately measure a frame loss between network relay devices even when the network relay device to be measured is connected by multipoint connection. It is in providing the measuring method and measuring system of this, and a network relay apparatus.

  The present invention was devised to achieve the above object, and transmits and receives a communication frame for frame loss measurement between a pair of measurement target network relay devices connected via a network. Is a method for measuring a frame loss between the measurement target network relay devices based on a frame counter value written in the communication frame, and a lower communication device connected to one measurement target network relay device, Of the lower-layer communication devices connected to the other network relay device to be measured, select the lower-layer communication device that the frame to be transmitted and received between the lower-layer communication devices must pass through both network devices to be measured, and select the selected lower-layer communication device. Only the frames to be transmitted and received between communication devices are counted by the network relay device to be measured, Based of the frame counter value is a measurement method of frame loss for measuring a frame loss between the network relay device of the measurement target.

  The network relay device to be measured determines that the frame is a frame to be transmitted / received between the selected lower communication devices when the transmission source address and the destination address of the frame to be transmitted / received are addresses of the selected lower communication device. You may count.

  The network relay device to be measured encapsulates a frame from the lower communication device and transmits it as an encapsulated frame to the network side, and releases the encapsulation of the encapsulated frame received from the network side. The network relay device to be measured is configured to transmit to a lower-level communication device, and the measurement target network relay device counts the frame when the destination address and the source address of the encapsulated frame to be transmitted / received are the addresses of the network relay device to be measured. May be.

  As the communication frame, ITU-T Y.T. The LMM and LMR specified in 1731 may be used.

  Further, the present invention transmits and receives a frame loss measurement communication frame between a pair of measurement target network relay devices connected via a network, and sets the frame counter value written in the communication frame by both network relay devices. Based on a network loss device between the measurement target network relay device, the measurement target network relay device, the lower communication device connected to one measurement target network relay device, and the other Of the lower-layer communication devices connected to the network relay device to be measured, select the lower-layer communication devices whose frames to be transmitted / received between the lower-layer communication devices must pass through both network relay devices to be measured. A transmission / reception processing unit that counts only frames transmitted and received between A frame loss measurement system comprising a measuring unit for measuring a frame loss between the network relay device of the measurement target based on the frame counter value count.

  The transmission / reception processing unit includes an address storage unit that stores an address of the selected lower-level communication device, a counter value storage unit that stores a frame counter value, and a transmission source address and a destination address of a frame to be transmitted and received are the address storage unit A determination unit that determines that the frame is a frame to be transmitted / received between the selected lower-level communication devices, and increments the frame counter value of the counter value storage unit, A frame processing unit that writes a frame counter value stored in the counter value storage unit into the communication frame when the communication frame is transmitted and received.

  The transmission / reception processing unit encapsulates a frame from the lower communication device and transmits it as an encapsulated frame to the network side, and decapsulates the encapsulated frame received from the network side, , An address storage unit for storing the address of the other network relay device to be measured, a counter value storage unit for storing a frame counter value, and a destination address and a source address of the encapsulated frame to be transmitted Is the address of the network relay device to be measured, the determination unit for incrementing the frame counter value of the counter value storage unit, and the frame counter value of the counter value storage unit during the transmission / reception of the communication frame The frame processor to write to the frame It may be e.

  Furthermore, the present invention provides a network relay for transmitting and receiving a frame loss measurement communication frame to and from another network relay device connected via a network and measuring a frame loss with the other network relay device. Among the lower-layer communication devices connected to the network relay device and the lower-layer communication devices connected to the other network relay device, a frame that is transmitted and received between the lower-layer communication devices is a network relay device to be measured Each of the lower-layer communication devices that always pass through, and a transmission / reception processing unit that counts only frames transmitted and received between the selected lower-level communication devices, and the other network relay based on the frame counter value counted by the transmission / reception processing unit A network relay device with a measuring unit that measures frame loss between devices. .

  According to the present invention, frame loss between network relay devices can be accurately measured even when the network relay device to be measured is connected by multipoint connection.

1 is a schematic view of a frame loss measurement system of the present invention. FIG. 2A is a block diagram of the network relay device of the present invention, and FIG. 2B is an enlarged view of one of its ports. It is a block diagram of the network relay device of the present invention, and is a block diagram when two network relay devices are connected via a network. It is a figure explaining the frame structure of LMM and LMR. It is a figure explaining the measuring method of the frame loss using LMM and LMR. 6A to 6C are diagrams for explaining a conventional method for measuring a frame loss.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

  The frame loss measuring method of the present invention is a method of measuring a frame loss between network relay devices connected by multipoint connection.

  First, a frame loss measurement system used in the frame loss measurement method according to the present embodiment will be described.

  FIG. 1 is a schematic diagram of a frame loss measurement system according to the present embodiment.

  As shown in FIG. 1, a frame loss measurement system 1 transmits and receives a communication frame for frame loss measurement between a pair of network relay devices A and B to be measured connected via a network 2 and both networks. Based on the frame counter value written in the communication frame by the relay devices A and B, the frame loss between the network relay devices A and B to be measured is measured.

  The network relay devices A and B to be measured are connected via the network 2. Further, a network relay device C that is not a measurement target is connected to the network relay devices A and B via the network 2. As described above, the network relay devices A, B, and C are multipoint connected via the network 2.

  One communication target network relay device A is connected to a lower communication device D. The lower communication device E is connected to the other network relay device B to be measured. Frames transmitted and received between the lower communication device D and the lower communication device E are always arranged to pass through the network relay device A and the network relay device B.

  The network relay devices A, B, and C are switching hubs, for example, and the lower communication devices D and E are terminals such as PCs (Personal Computers).

  As a communication frame for frame loss transmitted and received between the network relay devices A and B to be measured, ITU-T Y.T. The LMM and LMR specified in 1731 are used.

  In the present embodiment, a case will be described in which the frame loss between the network relay devices A and B is mainly measured by the network relay device A. That is, the network relay device A transmits an LMM to the network relay device B, and measures the frame loss based on the frame counter value stored in the LMR received from the network relay device B.

  As shown in FIG. 2A, network relay devices A and B, which are network relay devices of the present invention, are provided corresponding to a plurality of ports 20 and the respective ports 20 and transmit / receive via the ports 20. A transmission / reception processing unit 21 that performs the transmission / reception processing of the above, a control unit 22 that processes LMM and LMR and measures frame loss, and a switch mechanism 23 that transfers frames between the ports 20. The transmission / reception processing unit 21 includes a reception processing unit 24 and a transmission processing unit 25.

  When receiving a frame at a certain port 20 in the network relay devices A and B, the reception processing unit 24 refers to an FDB (Forwarding Database) (not shown) according to the destination address of the received frame and determines the forwarding destination port 20. To the switch mechanism. The switch mechanism 23 transfers the frame to the transmission processing unit 25 corresponding to the transfer destination port 20. The transmission processing unit 25 transmits a frame from the transfer destination port 20.

  FIG. 2B is an enlarged view of one port 20 in the network relay devices A and B.

  As shown in FIG. 2B, the reception processing unit 24 and the transmission processing unit 25 include an address storage unit 201 in common. The reception processing unit 24 and the transmission processing unit 25 may each include an address storage unit. The address storage unit 201 stores a destination address and a source address of a frame to be counted.

  The reception processing unit 24 determines whether or not the frame received via the port 20 is a frame at the address stored in the address storage unit 201 and the reception counter 202 as a counter value storage unit that stores the frame counter value. The reception side determination unit 203 increments the frame counter value of the reception counter 202 when it is determined to be the frame of the address stored in the address storage unit 201, and the frame counter value of the reception counter 202 is written into the LMM when receiving the LMM. The reception side frame processing unit 204 transfers the received LMR and the frame counter value of the reception counter 202 at the time of LMR reception to the control unit 22 at the time of LMR reception.

  The control unit 22 includes an LMM transmission unit 206 that transmits an LMM, an LMM-LMR conversion unit 207 that converts an LMM into an LMR and transmits the received LMM, and a frame counter value (TxFCf, RxFCf, TxFCb) and a frame counter value storage unit 208 that stores the frame counter value (RxFCl) of the reception counter 202 at the time of LMR reception transferred from the reception processing unit 24, and each frame counter value stored in the frame counter value storage unit A measurement unit 205 that measures the frame loss based on the LMR discard unit 209 that discards the received LMR is provided.

  The transmission processing unit 25 determines a transmission counter 210 as a counter value storage unit that stores the frame counter value, and determines whether or not the frame to be transmitted is a frame of an address stored in the address storage unit 201. When it is determined that the frame is at the address stored in 201, the transmission side determination unit 211 increments the frame counter value of the transmission counter 210, and the frame counter value of the transmission counter 210 is set to LMM and LMR when transmitting LMM and LMR. A transmission side frame processing unit 212 for writing and transmitting this via the port 20.

  In the network relay devices A and B, predetermined ports are set as ports for measuring frame loss. For example, the port is set by the network administrator communicating with the network relay devices A and B through the PC terminal. In the present embodiment, the port connected to the network relay device B of the network relay device A is set as a port for transmitting the LMM. Also, the port connected to the network relay device A of the network relay device B is set as a port for transmitting LMR.

  In the present embodiment, the addresses of the lower-layer communication devices D and E are stored in the address storage unit of the set port and the port that transmits the LMM of the network relay device A. Similarly, the addresses of the lower-layer communication devices D and E are stored in the address storage unit of the LMR transmission port of the network relay device B and the set port. For example, the network administrator communicates with the network relay devices A and B through the PC terminal by storing the address in the address storage unit.

  As an address stored in the address storage unit, a MAC address or an IP address can be used.

  FIG. 3 shows the port 20a and the network relay device 20b of the network relay device A connected via the network 2.

  The port 20a of the network relay device A is set as a port for transmitting LMM. The address storage unit 201a stores the addresses of the lower-level communication devices D and E as destination addresses.

  Based on the address storage unit 201a, the reception side determination unit 203a of the reception processing unit 21a of the network relay device A has the transmission source address of the frame received through the port 20a as the address of the lower communication device E and the destination address as the lower address. When it is the address of the communication device D, the frame counter value of the reception counter 202a is incremented (counted).

  The transmission side determination unit 211a of the transmission processing unit 25a of the network relay device A is based on the address storage unit 201a, and the transmission source address of the frame to be transmitted is the address of the lower communication device D and the destination address is the address of the lower communication device E In this case, the frame counter value of the transmission counter 210a is incremented (counted).

  The port 20b of the network relay device B is set as a port for transmitting LMR. The address storage unit 201a stores the addresses of the lower-level communication devices D and E.

  The reception side determination unit 203b of the reception processing unit 24b of the network relay device B is based on the address storage unit 201b, and the source address of the frame received via the port 20b is the address of the lower communication device D, and the destination address is lower. When it is the address of the communication device E, the frame counter value of the reception counter 202b is incremented (counted).

  The transmission side determination unit 211b of the transmission processing unit 25b of the network relay device B is based on the address storage unit 201b, the transmission source address of the frame to be transmitted is the address of the lower communication device E, and the destination address is the address of the lower communication device D In this case, the frame counter value of the transmission counter 210b is incremented (counted).

  Here, the LMM and LMR frame structures will be described.

  As shown in FIG. 4, LMM and LMR are Ethernet OAM (Operation Administration and Maintenance) frames (Ethernet is a registered trademark), DA (Destination Address) 31, SA (Source Address) 32, S-TAG (Service VLAN Tag) 33, EtherType (Ethernet type) 34 in which identification of Ethernet OAM is stored, MD (Maintenance Domain) Level + version (maintenance domain level + version) 35, LMM or LMR OP code (operation code) 36, Flags (flag) 37, TLV (Type / Length / Value) offset (TLV offset) 38, Data (data) 39, END TLV (end TLV) 40, F Including each region of the S (Flame Check Sequence) 41.

  When this frame is an LMM, a code “43” indicating the LMM is stored in the area of the OP code 36 in the frame. In this embodiment, since the LMM is transmitted from the network relay device A to the network relay device B, the MAC address of the network relay device B is stored in the area of DA31, and the MAC of the network relay apparatus A is stored in the area of SA32. Stores the address.

  When this frame is LMR, a code “42” indicating that it is LMR is stored in the area of OP code 36 in the frame. In this embodiment, since the LMR is transmitted from the network relay device B to the network relay device A, the MAC address of the network relay device A is stored in the DA31 area, and the MAC address of the network relay device B is stored in the SA32 area. Stored.

  The area of Data 39 includes TxFCf 42 that stores a frame counter value at the time of LMM transmission, RxFCf 43 that stores a frame counter value at the time of LMM reception, and TxFCb 44 that stores a frame counter value at the time of LMR transmission.

  The code for identifying the LMM and LMR can be uniquely set by the vendor of the network relay device within the scope of the OAM frame standard.

  Next, a frame loss measurement method according to this embodiment will be described.

  When the network relay devices A and B to be measured are connected by multipoint connection, counting the frames that pass through only one of the network relay devices A and B or the frames that are flooded when the destination is unknown will result in an accurate frame loss. It becomes impossible to measure. Therefore, it is necessary to count only frames that reliably pass through both network relay devices A and B.

  Therefore, in the present invention, only the frames transmitted and received between the lower communication device D under the network relay device A and the lower communication device E under the network relay device B are counted by the network relay devices A and B. I tried to do it.

  As the lower-level communication devices D and E, a frame that is transmitted and received between the lower-level communication devices D and E is selected so that it always passes through the network relay devices A and B.

  As an example, a case where the frame X is transmitted from the lower communication device D to the lower communication device E will be described. The address of the lower communication device D is stored in the transmission source address of the frame X, and the address of the lower communication device E is stored in the destination address.

  The frame X transmitted by the lower communication device D is received at a certain port of the network relay device A. The frame X is transferred from the certain port to the transmission processing unit 25a of the port 20a by the switch mechanism 23a.

  The transmission side determination unit 211a of the transmission processing unit 25a of the network relay device A refers to the transmission source address and the destination address of the frame X, and the transmission source address stored in the address storage unit 201a is the address of the lower communication device D. Yes, it is determined whether the destination address is the address of the lower communication device E. Since the address of the lower communication device D is stored in the transmission source address of the frame X and the address of the lower communication device E is stored in the destination address, the transmission side determination unit 211a increments the frame counter value of the transmission counter 210a. To do. Thereafter, the transmission processing unit 25a transmits the frame X from the port 20a.

  The frame X transmitted from the network relay device A is received at the port 20b of the network relay device B and sent to the reception processing unit 24b. The reception side determination unit 203b of the reception processing unit 24b refers to the transmission source address and the destination address of the frame X, and whether the transmission source address is the address of the lower communication device D and the destination address is the address of the lower communication device E. Judging. Since the address of the lower communication device D is stored in the transmission source address of the frame X and the address of the lower communication device E is stored in the destination address, the reception side determination unit 203b increments the frame counter value of the reception counter 202b. To do.

  The receiving side determination unit 203b refers to the FDB based on the destination address of the frame X and determines a transfer destination port. The switch mechanism 23b transfers the frame to the transmission processing unit of the port connected to the lower communication device E.

  As described above, when the frame X is transmitted from the lower communication device D to the lower communication device E, the frame counter value of the transmission counter 210a of the network relay device A and the frame counter value of the reception counter 202b of the network relay device B are incremented. Is done.

  Similarly, when a frame is transmitted from the lower communication device E to the lower communication device D, the frame counter value of the transmission counter 210b of the network relay device B and the frame counter value of the reception counter 202a of the network relay device A are incremented. .

  The frames other than the frames transmitted and received between the lower communication devices D and E are counted by both the network relay devices A and B because either the transmission source address or the destination address is not the address of the lower communication devices D and E. Not.

  When measuring the frame loss, first, the LMM transmission unit 206a of the control unit 22a of the network relay device A that is the measurement subject transmits the LMM. The transmission side frame processing unit 212a of the transmission processing unit 25a stores the frame counter value of the transmission counter 210a in the area of the TxFCf 42 of the LMM, and transmits it to the network relay device B via the port 20a.

  The LMM received by the network relay device B is sent to the reception processing unit 24b via the port 20b. The reception side frame processing unit 204b of the reception processing unit 24b stores the frame counter value of the reception counter 202b in the area of RxFCf43 of the LMM and outputs it to the control unit 22b.

  The LMM-LMR conversion unit 207b of the control unit 22b replaces the address (address of the network relay device B) stored in the DA31 area of the LMM and the address (address of the network relay device A) stored in the SA32 area. , The code (42) indicating the LMR is stored in the area of the OP code 36, the LMM is converted into the LMR, and output to the transmission processing unit 25b.

  The transmission side frame processing unit 212b of the transmission processing unit 25b stores the frame counter value of the transmission counter 210b in the area of the TxFCb 44 of the LMM, and transmits it to the network relay device A via the port 20b.

  The LMR transmitted from the network relay device B is received by the network relay device A and sent to the reception processing unit 24a via the port 20a. The reception side frame processing unit 204a of the reception processing unit 24a transfers the received LMR and the frame counter value of the reception counter 202a at the time of LMR reception to the control unit 22a.

  The frame counter value storage unit 208a of the control unit 22a includes each frame counter value (TxFCf, RxFCf, TxFCb) stored in the LMR TxFCf42, RxFCf43, TxFCb44, and the frame counter value (RxFCl) of the reception counter 202a at the time of LMR reception. Remember. The received LMR is discarded by the LMR discard unit 209a.

  Similarly, the frame counter value (TxFCf, RxFCf, TxFCb) stored in the LMR transmitted from the LMM transmission unit of the network relay device A and received from the network relay device B, and the reception counter 202a at the time of LMR reception The frame counter value (RxFCl) is stored in the frame counter value storage unit.

Based on the frame counter value stored in the frame counter value storage unit 208a, the measurement unit 205a of the control unit 22a uses the following equations (1) and (2).
Frame loss (AtoB) = (TxFCf [2]) − TxFCf [1]) − (RxFCf [2] −RxFCf [1]) (1)
However, frame loss (AtoB): frame loss of a frame transmitted from the network relay device A to the network relay device B TxFCf [2]: frame counter value at the second LMM transmission TxFCf [1]: at the first LMM transmission Frame counter value RxFCf [2]: Frame counter value at second LMM reception RxFCf [1]: Frame counter value at first LMM reception Frame loss (BtoA) = (TxFCb [2] −TxFCb [1] )-(RxFCl [2] -RxFCl [1]) (2)
However, frame loss (BtoA): frame loss of a frame transmitted from the network relay device B to the network relay device A TxFCb [2]: frame counter value at the second LMR transmission TxFCb [1]: at the first LMR transmission Frame counter value RxFCl [2]: Frame counter value at the second LMR reception RxFCl [1]: Frame loss is obtained from the frame counter value at the first LMR reception.

  When it is found that a frame loss has occurred, congestion has occurred between the network relay devices A and B. For example, appropriate measures such as band limitation may be taken.

  As described above, in the frame loss measurement method according to the present embodiment, frames transmitted and received between the lower communication device D connected to the network relay device A and the lower communication device E connected to the network relay device B. However, the network relay devices A and B count only frames transmitted and received between the lower communication devices D and E by using the fact that both network relay devices A and B always pass, and the network is based on the frame counter value. The frame loss between the relay devices A and B is measured.

  Frames transmitted and received between the lower communication devices D and E always pass through the network relay devices A and B to be measured, so even if the network relay devices A and B are connected by multipoint connection, the lower communication By counting only frames transmitted and received between the devices D and E, it is possible to accurately measure the frame loss between the network relay devices A and B.

  In the above embodiment, a case has been described in which one lower communication device D connected to the network relay device A and one lower communication device E connected to the network relay device B are selected. However, the present invention is not limited to this. The lower communication devices may be targeted.

  For example, the lower communication devices D and F are connected to the network relay device A, the lower communication devices E and G are connected to the network relay device B, and transmission / reception is performed between the lower communication devices D and F and the lower communication devices E and G. When a frame to be transmitted always passes through both network relay devices A and B, the frames transmitted / received between lower communication devices D and E, between D and G, between F and E, and between F and G shall be counted. Can do.

  The lower-level communication device only needs to reliably pass through the network relay device A and the network relay device B at the time of frame transmission / reception. Therefore, the lower-level communication device may be a communication device connected to a lower level of the lower-level communication device. it can.

  Further, the network relay devices A and B may include an encapsulation unit defined in IEEE (American Institute of Electrical and Electronics Engineers) 802.1ah in the transmission / reception processing unit (reception processing unit 21a and transmission processing unit 21b). Good. The encapsulation means adds a header to the frame from the lower communication devices D and E to encapsulate it, transmits it as an encapsulated frame to the network 2 side, and removes the header of the encapsulated frame received from the network 2 side. The data is decapsulated and transmitted as a frame to the lower communication devices D and E. The network relay devices A and B are treated as edge devices, and the network relay devices A and B are connected via a network 2 as a backbone bridge network.

  In this case, the address storage unit stores the address of the encapsulation header of the paired measurement target network relay device. The address storage units of the network relay devices A and B store the addresses of the encapsulation headers of the network relay devices A and B, respectively.

  The receiving side determination unit of the network relay device A receives when the transmission source address of the received encapsulated frame is the address of the network relay device B and the destination address is the address of itself (network relay device A). The frame counter value of the counter 23a is incremented. The transmission side determination unit of the network relay device A transmits the transmission counter 23b when the transmission source address of the encapsulated frame to be transmitted is the address of itself (network relay device A) and the destination address is the address of the network relay device B. Increment the frame counter value. The same applies to the network relay device B.

  The encapsulated frame transmitted / received between the network relay devices A and B is always transmitted from one of the network relay devices A and B and received by the other. Therefore, if the encapsulated frame is counted by the network relay devices A and B to be measured, the frame loss between the network relay devices A and B can be accurately measured.

1 Frame loss measurement system 2 Network A, B Network relay device (measurement target)
C Network relay device (not subject to measurement)
D, E Lower-layer communication equipment

Claims (8)

Based on a frame counter value written to the communication frame by both network relay devices by transmitting / receiving a communication frame for frame loss measurement between a pair of measurement target network relay devices connected via a network, the measurement target A method for measuring frame loss between network relay devices of
Of the lower-level communication devices connected to one measurement target network relay device and the lower-level communication devices connected to the other measurement-target network relay device, the frames sent and received between the lower-level communication devices are Each lower communication device that always passes through the relay device is selected, only the frames that are transmitted and received between the selected lower communication devices are counted by the network relay device to be measured, and the network relay to be measured is based on the frame counter value. A method for measuring a frame loss, characterized by measuring a frame loss between devices.   The network relay device to be measured determines that the frame is a frame to be transmitted / received between the selected lower communication devices when the transmission source address and the destination address of the frame to be transmitted / received are addresses of the selected lower communication device. The frame loss measuring method according to claim 1, wherein the frame loss is counted. The network relay device to be measured encapsulates a frame from the lower communication device and transmits it as an encapsulated frame to the network side, and releases the encapsulation of the encapsulated frame received from the network side. Configured to transmit to lower-level communication devices,
2. The frame loss measurement method according to claim 1, wherein the network relay device to be measured counts the frame when the destination address and the source address of the encapsulated frame to be transmitted and received are addresses of the network relay device to be measured. .   As the communication frame, ITU-T Y.T. The frame loss measurement method according to claim 1 or 2, wherein LMM and LMR defined in 1731 are used. Based on a frame counter value written to the communication frame by both network relay devices by transmitting / receiving a communication frame for frame loss measurement between a pair of measurement target network relay devices connected via a network, the measurement target A system for measuring frame loss between network relay devices of
The network relay device to be measured is transmitted and received between lower communication devices among the lower communication device connected to one measurement target network relay device and the lower communication device connected to the other measurement target network relay device. The transmission / reception processing unit that selects only the lower-layer communication devices that must pass through both measurement target network relay devices, counts only frames that are transmitted / received between the selected lower-layer communication devices, and the frames counted by the transmission / reception processing unit. A frame loss measurement system comprising: a measurement unit that measures frame loss between the network relay devices to be measured based on a counter value.   The transmission / reception processing unit includes an address storage unit that stores an address of the selected lower-level communication device, a counter value storage unit that stores a frame counter value, and a transmission source address and a destination address of a frame to be transmitted and received are the address storage unit A determination unit that determines that the frame is a frame to be transmitted / received between the selected lower-level communication devices, and increments the frame counter value of the counter value storage unit, The frame loss measurement system according to claim 5, further comprising: a frame processing unit that writes a frame counter value of the counter value storage unit to the communication frame when the communication frame is transmitted and received.   The transmission / reception processing unit encapsulates a frame from the lower communication device and transmits it as an encapsulated frame to the network side, and decapsulates the encapsulated frame received from the network side, , An address storage unit for storing the address of the other network relay device to be measured, a counter value storage unit for storing a frame counter value, and a destination address and a source address of the encapsulated frame to be transmitted Is the address of the network relay device to be measured, the determination unit for incrementing the frame counter value of the counter value storage unit, and the frame counter value of the counter value storage unit during the transmission / reception of the communication frame The frame processor to write to the frame Frame loss measurement system of claim 5, wherein the obtaining. A network relay device that transmits and receives a communication frame for frame loss measurement with another network relay device connected via a network and measures a frame loss with the other network relay device,
Of the lower-layer communication devices connected to the network relay device and the lower-layer communication devices connected to the other network relay device, the frame that is transmitted and received between the lower-layer communication devices always passes through both measurement-target network relay devices. A transmission / reception processing unit that selects each communication device and counts only frames transmitted / received between the selected lower-level communication devices, and a frame counter value counted by the transmission / reception processing unit, between the other network relay device A network relay device comprising a measurement unit for measuring a frame loss.

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