JP2010088040A - Method and system for measuring relay delay time between relay apparatuses, and relay apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and system for measuring a relay delay time between relay apparatuses, wherein the relay delay time between the relay apparatuses is accurately measured, and also to provide a relay apparatus. <P>SOLUTION: The present invention relates to a measurement method of a relay delay time between relay apparatuses, for measuring a reciprocative relay delay time between a first relay apparatus A and a second relay apparatus B. The method includes measuring the relay delay time required for reciprocating predetermined times between the first relay apparatus and the second relay apparatus. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and system for measuring a relay delay time between relay devices that measures a round trip relay delay time between relay devices, and a relay device.

  In a service in which a plurality of terminals perform real-time communication with each other via the Internet, such as an IP (Internet Protocol) telephone, the delay time of communication between the terminals is one of the factors that degrade the quality of the service. . As a place where this delay occurs, there is a relay delay between relay devices constituting the network, and there is a request to measure the relay delay time between the relay devices.

  For the measurement of the relay delay time between conventional relay devices, ITU-T Y.T. There are methods using DMM (Delay Measurement Message) and DMR (Delay Measurement Reply) defined in J. 1731.

  For example, when measuring the round trip relay delay time between the relay devices A and B, the relay device B transmits the DMM from the relay device A to the relay device B, and the relay device B that receives the DMM converts the DMM into a DMR and relays the relay device. The relay device A returns to A and receives the DMR, and measures the time from the time when the DMM is transmitted to the time when the DMR is received. The relay device A stores the time of the moment when the DMM is transmitted in the frame of the DMM, acquires the time of the moment when the DMR is received, and compares the time when the DMR is received with the time when the DMM in the DMR is transmitted. Thus, the relay delay time can be obtained. The measured relay delay time (the time from when the DMM is transmitted until the DMR is received) is, for example, about several hundred μsec.

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

JP 2007-180611 A

  As shown in FIG. 6, in the relay device A, the transmission-side line card 61 and the reception-side line card 62 may be separated. In such a case, when the above-described measurement of the relay delay time is performed by hardware processing, the hardware of the transmission-side line card 61 and the hardware of the reception-side line card 62 synchronize the built-in clock. It is necessary to let When the clocks are not synchronized, the transmission side line card 61 acquires the time when the DMM is transmitted, and the reception side line card 62 acquires the time when the DMR is received, so the time when the DMR is received and the time when the DMM is transmitted Therefore, an error between the clock of the line card 61 on the transmission side and the clock of the line card 62 on the reception side is included in the relay delay time obtained from the above.

  Since the relay delay time to be measured is about several hundred μsec, it is necessary to suppress the clock error to about several μsec, and it is necessary to synchronize the hardware clock with an error of about several μsec. In the case of the relay device A shown in FIG. 6, it is necessary to realize a clock synchronized with an error of about several μsec between the packet circuits 63 mounted on the line cards 61 and 62.

  When there is no means for synchronizing the hardware clock between the transmission side line card 61 and the reception side line card 62 of the relay device A, the relay delay time is measured by software processing in the CPU 65 of the management module 64. There is a need.

  However, when measuring the relay delay time by software processing, an error due to the software processing time becomes a problem.

  Referring to FIGS. 6 and 7, when the measurement of the relay delay time is performed by software processing, transmission processing for issuing a command for transmitting the DMM from the CPU 65 of the management module 64 to the transmission line card 61 is performed. At the same time, the time when the transmission process is started is stored. The transmission line card 61 transmits the DMM to the relay device B. The receiving line card 62 receives the DMR returned from the relay device B, and sends the received DMR to the memory of the CPU 65. The CPU 65 performs DMR reception processing and stores the time when the reception processing is performed. The CPU 65 obtains the relay delay time from the time when the reception process is completed and the time when the transmission process is performed.

  As shown in FIG. 7, it takes about several hundred msec for the software transmission processing time in the CPU 65 until the transmission line card 61 transmits the DMM after the CPU 65 starts the transmission processing. Further, it takes about several hundreds of milliseconds for the CPU 65 to receive the software after the receiving line card 62 receives the DMR until the CPU 65 finishes the receiving process. The relay delay time obtained by the CPU 65 includes the processing time of software transmission processing and reception processing in the actual relay delay time between the relay devices A and B.

  While the actual relay delay time between the relay devices A and B is about several hundreds of microseconds, the processing time for software transmission processing and reception processing is about several hundreds of milliseconds, so an accurate value of the actual relay delay time can be obtained. It could not be measured.

  Accordingly, an object of the present invention is to provide a measuring method and measuring system for a relay delay time between relay devices and a relay device capable of accurately measuring the round trip relay delay time between the relay devices.

  The present invention was devised to achieve the above object, and the invention according to claim 1 relates to a relay device that measures a round trip relay delay time between the first relay device and the second relay device. The relay delay time is measured between the relay devices, wherein the relay delay time is measured when the relay device makes a predetermined number of round trips between the first relay device and the second relay device. This is a method for measuring the relay delay time.

  The invention according to claim 2 is characterized in that the first delay device and the second relay device are divided by the predetermined number of times to divide the relay delay time required when the predetermined number of times of round trip between the first relay device and the second relay device. The method of measuring a relay delay time between relay devices according to claim 1, wherein a round trip relay delay time between the relay device and the second relay device is calculated.

  According to a third aspect of the present invention, the first relay device transmits a first frame to the second relay device, the second relay device receives the first frame, and the first relay device receives the first frame. Frame is converted to a second frame, and the second frame is transmitted to the first relay device. The first relay device receives the second frame, and converts the second frame into the second frame. The first frame is converted to the first frame, the first frame is transmitted to the second relay device, and the first frame and the second frame are transmitted between the first relay device and the second relay device. The relay delay time required when the frame is reciprocated a predetermined number of times between the first relay device and the second relay device by performing the frame reciprocal exchange for the predetermined number of times. 2 is a method for measuring a relay delay time between relay devices.

  In the invention according to claim 4, when the first first frame is transmitted from the first relay device, the first relay device receives the first frame internally, and the reception time of the first first frame is determined. The first relay device receives the second frame after measuring and reciprocating the predetermined number of times between the first relay device and the second relay device. The second frame reception time is measured, and the first relay device and the second frame are calculated from the difference between the reception time of the second frame after the predetermined number of round trips and the reception time of the first first frame. 4. The method of measuring a relay delay time between relay devices according to claim 3, wherein the relay delay time required when the predetermined number of round trips between the relay devices is measured.

  According to a fifth aspect of the present invention, the first frame and the second frame include a region for holding a round-trip number between the first relay device and the second relay device, and the first relay The device converts the received second frame into the first frame, increments the number of round-trips of the area, and transmits the first frame to the second relay device. It is the measuring method of the relay delay time between the described relay apparatuses.

  According to a sixth aspect of the present invention, there is provided an ITU-T Y.3 as the first frame and the second frame. 6. The method for measuring a relay delay time between relay devices according to claim 3, wherein DMM and DMR defined in 1731 are used.

  The invention according to claim 7 is a system for measuring a relay delay time between relay devices that measures a round trip relay delay time between a first relay device and a second relay device, wherein the first relay device Is a system for measuring a relay delay time between relay devices, comprising means for measuring a relay delay time required for a predetermined number of round trips to and from the second relay device.

  According to an eighth aspect of the present invention, the first relay device sets a relay delay time required when the first relay device makes a round trip between the first relay device and the second relay device for the predetermined number of times. 8. The relay delay time measuring system between relay devices according to claim 7, wherein a round trip relay delay time between the first relay device and the second relay device is calculated by dividing.

  In the invention according to claim 9, the second relay device receives the first frame from the first relay device, converts the first frame into a second frame, and converts the second frame into the second frame. Means for transmitting a frame to the first relay device, wherein the first relay device receives the second frame, converts the second frame into the first frame, and Means for transmitting the first frame to the second relay device, wherein the first relay device and the second relay device exchange the round trip between the first frame and the second frame a predetermined number of times. The relay delay time measurement system between relay devices according to claim 7 or 8.

  In the invention according to claim 10, when the first relay device transmits the first first frame, the first relay device internally receives the first frame, measures the reception time of the first first frame, and receives the first frame. Receiving the second frame after the predetermined number of round trips between the relay equipment and the second relay equipment, measuring the reception time of the second frame after the predetermined round trips, A round trip between the first relay device and the second relay device for the predetermined number of times based on the difference between the reception time of the second frame and the reception time of the first first frame. The relay delay time measuring system between relay devices according to claim 9 for measuring the relay delay time.

  According to an eleventh aspect of the present invention, the first frame and the second frame include a region for holding a round-trip number between the first relay device and the second relay device, and the first relay The device converts the received second frame into the first frame, increments the number of round-trips of the area, and transmits the first frame to the second relay device. It is a measurement system of the relay delay time between the described relay apparatuses.

  According to a twelfth aspect of the present invention, as the first frame and the second frame, ITU-T Y. 12. The method for measuring a relay delay time between relay devices according to claim 9, wherein DMM and DMR specified in 1731 are used.

  According to a thirteenth aspect of the present invention, there is provided a relay device comprising means for measuring a relay delay time required for a predetermined number of round trips to and from another relay device.

  According to a fourteenth aspect of the present invention, the means is configured to divide a relay delay time required for the predetermined number of round trips with the other relay device by the predetermined number of times. 14. The relay device according to claim 13, which calculates a round trip relay delay time between the relay devices.

  In the invention according to claim 15, the means transmits the first frame to the other relay device, receives the second frame from the other relay device, and sends the second frame to the first relay device. The first frame is transmitted to the second relay device, and the round-trip exchange between the first frame and the second frame is performed with the predetermined relay device. 15. The relay device according to claim 13 or 14, wherein the relay delay time is measured when the predetermined number of round trips are performed with the other relay device by performing the number of times.

  According to a sixteenth aspect of the present invention, when the means transmits the first first frame, the means receives the first first frame, measures the reception time of the first first frame, and determines the other relay. Receiving the second frame after the predetermined number of round-trips with the device, measuring the reception time of the second frame after the predetermined number of round-trips, 16. The relay device according to claim 15, wherein a relay delay time required when the predetermined number of round trips between the other relay devices is determined from a difference between the reception time of the first frame and the reception time of the first first frame. It is.

  According to a seventeenth aspect of the present invention, the first frame and the second frame include an area for holding a round-trip count with the other relay device, and the means includes the received second frame. The relay device according to claim 15 or 16, wherein the relay device converts the first frame and increments the number of round-trips of the area to transmit the first frame to the other relay device.

  According to an eighteenth aspect of the present invention, there is provided an ITU-T Y.T. The relay device according to any one of claims 15 to 17, wherein a DMM defined in 1731 is used.

  According to the present invention, the round-trip relay delay time between relay devices can be accurately measured.

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

  FIG. 1 is a schematic diagram of a measurement system for a relay delay time between relay devices according to the present embodiment.

  As shown in FIG. 1, the measurement system 1 for the relay delay time between relay devices is a system that measures the round trip relay delay time between the relay devices A and B.

  In FIG. 1, although the diagram is simplified, the relay devices A and B are connected via a network, and various devices are connected to this network.

  In FIG. 1, DMR (Delay Measurement Message) (“first frame”) is transmitted from the relay device A to the relay device B, and the DMR (Delay Measurement Reply) (“first” is returned from the relay device B to the relay device A. The case where the relay device A receives the second frame ")" will be described. The relay devices A and B are switching hubs.

  The relay delay time measurement system 1 between relay devices reciprocates the DMM / DMR between the relay devices A and B to delay the relay delay time to a level that can be measured by software. Here, a case where the number of reciprocations is set to n times will be described.

  The relay device A that is a switching hub of the present invention includes a DM control circuit 2 that converts the DMR received from the relay device B into a DMM, a DMM that is transmitted from the relay device A, and a packet that analyzes the DMR received from the relay device B. An analysis circuit 3 and a software processing unit 4 that calculates a relay delay time by software processing are provided.

  The DM control circuit 2 stores a DMR-DMM conversion circuit 5 that converts the DMR received from the relay device B into a DMM, and a DMR round-trip count r output from the DMR-DMM conversion circuit 5 (see FIG. 4). And an increment circuit 6 that increments the number of round-trip times r. The frame structure of DMM and DMR will be described later.

  The packet analysis circuit 3 receives the transmission request from the software processing unit 4, copies the software request receiving circuit 7 that transmits the DMM, and copies the first DMM transmitted from the software request receiving circuit 7. Of the DMR received from the relay device B and the DMR received from the relay device B is copied to the software processing unit 4 after the n-round trip between the relay devices A and B. A receiving-side copy circuit 9 that transfers to the software processing unit 4 and a DMR discarding circuit 10 that discards the DMR after n round-trips that have passed through the receiving-side copy circuit 9 are provided. Hereinafter, the round-trip times r stored in the DMM and DMR are shown in parentheses as DMM (r) and DMR (r). DMM (0) represents the first DMM, and DMR (n-1) represents the DMR after n round trips between the relay devices A and B.

  The software processing unit 4 receives the first DMM (0) transferred from the transmission side copy circuit 8 and receives the first DMM (0) from the reception side copy circuit 8, and the reception side copy circuit 9 transfers the received time. Difference between reception times measured by the second reception time measurement unit 12 that receives the received DMR (n-1) and measures the time when the DMR (n-1) is received, and the first reception time measurement unit 11 and the second reception time measurement unit 12 And a relay delay time measuring unit 13 for calculating the relay delay time by determining the time difference of the delay time and dividing the time difference of the delay time by the number of round trips n.

  Although not shown, the software processing unit 4 includes a measurement start command output unit that outputs a command for transmitting the first DMM (0) to the software request receiving circuit 7, and a round-trip number storage that stores a preset round-trip number n. And a reception time storage unit that stores the reception times measured by the first reception time measurement unit 11 and the second reception time measurement unit 12.

  The DMR-DMM conversion circuit 5, the increment circuit 6, the software request reception circuit 7, the transmission side copy circuit 8, the reception side copy circuit 9, and the DMR discard circuit 10 are realized by hardware. Here, the hardware is, for example, an LSI dedicated to a specific process. The first reception time measurement unit 11, the second reception time measurement unit 12, the relay delay time measurement unit 13, and the measurement start command output unit are realized by software processing. The round-trip number storage unit and the reception time storage unit are realized by a memory.

  As shown in FIG. 2, when the relay device A transmits the first DMM (0), it transmits this to the relay device B and copies the DMM (0) by the transmission side copy circuit 8 for software processing. The first reception time measurement unit 11 measures the reception time.

  When DMR (r) is received from the relay device B, it is replaced with DMM (r) by the DMR-DMM conversion circuit 5, and the round trip number r is incremented by the increment circuit 6 to obtain DMM (r + 1). Transmit to relay device B.

  Further, when DMR (n−1) after n round-trips is received from the relay device B, it is copied by the receiving side copy circuit 9 and transferred to the software processing unit 4. The software processing unit 4 measures the reception time by the second reception time measurement unit 12. The original DMR (n−1) is discarded by the DMR discard circuit 10.

  On the other hand, the relay device B includes a DM control circuit 14 that converts the DMM received from the relay device A into a DMR and transmits it. The DM control circuit 14 includes a DMM-DMR conversion circuit 15 that converts received DMM into DMR.

  As shown in FIG. 3, the relay device B replaces the DMM (r) received from the relay device A with the DMR (r) by the DMM-DMR conversion circuit 15, and returns the DMR (r) to the relay device A.

  Here, the frame structure of DMM and DMR will be described.

  As shown in FIG. 4, DMM and DMR are Ethernet OAM (Operation Administration and Maintenance) frames (Ethernet is a registered trademark), a destination MAC address (DA) 41, a source MAC address (SA). 42, a VLAN tag (VLAN TAG) 43, an Ethernet type (CFM EtherType) 44 storing an identification of Ethernet OAM, a maintenance domain (MD) level version (MD Level + version) 45, a DMM or a DMR An operation code (OP code) 46, a flag (Flags) 47, a TLV (Type / Length / Value) offset (TLV offset) 48, a DMMTLV (DMM TLV) 49, and a round trip count r are stored. Add TLV50, including each region of the end TLV (END TLV) 51, padding data (Padding Data) 52, FCS (Flame Check Sequence) 53. That is, the frame structure of the DMM and DMR used in this embodiment is obtained by adding an additional TLV 50 that stores the number of round-trip times r in a normal Ethernet OAM frame.

  When this frame is DMM, the MAC address of the relay device B is stored in the destination MAC address 41 in the frame, and the MAC address of the relay device A is stored in the source MAC address 42. The operation code 46 stores a code “47” indicating DMM.

  When this frame is a DMR, the MAC address of the relay device A is stored in the destination MAC address 41 in the frame, and the MAC address of the relay device B is stored in the source MAC address 42. In addition, the operation code 46 stores a code “46” indicating DMR.

  The codes for identifying the DMM and DMR can be uniquely set by the vendor of the relay device within the scope of the OAM frame standard.

  Next, a method for measuring the relay delay time between relay devices will be described.

  As shown in FIG. 5, first, the first DMM (0) is transmitted from the relay device A to the relay device B. The number of reciprocations n for reciprocating between the relay devices A and B is set in advance and stored in the reciprocation number storage unit of the relay device A.

  More specifically, the software processing unit 4 (measurement start command output unit) of the relay device A outputs a command for transmitting the first DMM (0) to the software request receiving circuit 7, and receives this to receive the software request receiving circuit. 7 sends the first DMM (0). The destination MAC address 41 of DMM (0) stores the MAC address of relay device B, the source MAC address 42 stores the MAC address of relay device A, and the additional TLV 50 stores the number of round trips r = 0.

  The transmission side copy circuit 8 refers to the round-trip number r stored in the additional TLV 50 of the DMM (0) input from the software request reception circuit 7, and when r = 0, copies the DMM (0) 1 Transfer to reception time measuring unit 11. Since r = 0 is stored in the additional TLV 50 of the first DMM (0), the transmission side copy circuit 8 copies the DMM (0) and transfers it to the first reception time measuring unit 11.

The first reception time measurement unit 11 measures the reception time t ₁ ′ when the DMM (0) transferred from the transmission side copy circuit 8 is received. The reception time t ₁ ′ is delayed by the time (several hundred msec) required for the software reception process from the time t ₁ when the DMM (0) is actually transmitted. The reception time t ₁ ′ measured by the first reception time measurement unit 11 is stored in the reception time storage unit. The DMM (0) that has passed through the transmission side copy circuit 8 is transmitted to the relay device B.

  The relay device B that has received the DMM (0) replaces the DMM (0) with the DMR (0) by the DMM-DMR conversion circuit 15 (the destination MAC address 41 and the source MAC address 42 are replaced, and the operation code 46 The DMR (0) is returned to the relay device A after storing the code indicating the DMR.

  The receiving side copy circuit 9 of the relay device A that has received the DMR (0) from the relay device B refers to the round trip number r (in this case, r = 0) stored in the additional TLV 50 of the received DMR (0). R = n−1, DMR (n−1) is copied and transferred to the second reception time measurement unit 12. Here, since DMR (0) is not r = n−1, DMR (0) is passed through without being transferred, and is output to the DMR discard circuit 10.

  The DMR discard circuit 10 refers to the round-trip number r (in this case, r = 0) stored in the additional TLV 50 of the received DMR (0). If r = n−1, the DMR (n−1) is determined. Discard. Here, since DMR (0) is not r = n−1, DMR (0) is passed as it is without being discarded, and is output to the DMR-DMM conversion circuit 5.

  The DMR-DMM conversion circuit 5 replaces DMR (0) with DMM (0) (replaces the destination MAC address 41 and the source MAC address 42 and stores a code indicating DMM in the operation code 46), and DMM (0) is output to the increment circuit 6.

  The increment circuit 6 increments the round-trip count r stored in the additional TLV 50 of the input DMM (0) to obtain DMM (1), and outputs this to the software request reception circuit 7.

  The software request receiving circuit 7 passes the input DMM (1) as it is. The transmission side copy circuit 8 refers to the round trip number r (in this case, r = 1) stored in the additional TLV 50 of the DMM (1) input from the software request reception circuit 7 and passes through as it is because r = 0 is not satisfied. Let The DMM (1) that has passed through the transmission side copy circuit 8 is transmitted to the relay device B.

  By repeating the above, the DMM / DMR is reciprocated n times between the relay devices A and B. The DMR-DMM conversion circuit 5, the increment circuit 6, the software request reception circuit 7, the transmission side copy circuit 8, the reception side copy circuit 9, the DMR discard circuit 10, and the DMM-DMR conversion circuit 15 are configured by hardware. Therefore, there is almost no delay when processing is performed in each circuit.

  The receiving side copy circuit 9 that has received the DMR (n−1) after n round trips between the relay devices A and B receives the round trip number r (in this case, stored in the additional TLV 50 of the received DMR (n−1)). With reference to r = n−1), since r = n−1, DMR (n−1) is copied and transferred to the second reception time measurement unit 12.

The second reception time measuring unit 12 measures the reception time t ₂ ′ when the DMR (n−1) transferred from the reception side copy circuit 9 is received. The reception time t ₂ ′ is delayed by the time (several hundred msec) required for the software reception process from the time t ₂ when the DMR (n−1) is actually received. The reception time t ₂ ′ measured by the second reception time measurement unit 12 is stored in the reception time storage unit.

  The DMR (n−1) that has passed through the receiving side copy circuit 9 is input to the DMR discard circuit 10. The DMR discard circuit 10 refers to the round trip number r (in this case, r = n−1) stored in the additional TLV 50 of the received DMR (n−1), and r = n−1. n-1) is discarded.

The relay delay time measurement unit 13 calculates the following equation (1) from the reception time t ₁ ′ measured by the first reception time measurement unit 11 and the reception time t ₂ ′ measured by the second reception time measurement unit 12.
T ′ = t ₂ ′ −t ₁ ′ (1)
To obtain the time difference T ′ of the relay delay time, and further, the following equation (2)
T _d = T ′ / n (2)
As shown in FIG. 5, the actual relay delay time _Td between the relay devices A and B is calculated by dividing the time difference T ′ of the relay delay time by the number of round trips n.

Thus, the relay delay time _Td between the relay devices A and B is obtained.

Software reception time when measuring the reception time t ₁ ′ of the first DMM (0) and software reception time when measuring the reception time t ₂ ′ of the DMR (n−1) after n round trips Since the processing time is substantially the same, the time difference T ′ between the relay delay times obtained from the reception times t ₁ ′ and t ₂ ′ is the actual transmission time t ₁ and DMR (n−1) of the DMM (0). ) is substantially equal to the time difference T of the relay delay time calculated from the reception time t ₂ of the. Therefore, by dividing the time difference T ′ of the relay delay time by the number of round trips n, it is possible to accurately obtain the actual relay delay time T _d between the relay devices A and B of about several hundred μsec.

  Here, the number of reciprocations n for reciprocating between the relay devices A and B will be considered.

When the time required for the software reception processing is T _s , the error β (software reception processing time) ratio β is expressed by the following equation (3).
β = T _s / (T _d × n + T _s ) × 100 (3)
It is represented by Assuming that the relay delay time T _d is 100 μsec and the time T _s required for the software reception processing is 100 msec, the error ratio β is a value shown in Table 1 when the number of round trips n is varied from 1 to 10,000.

  As shown in Table 1, when the number of reciprocations n is 100 or less, the error ratio β increases to 90% or more. When the number of reciprocations n is 1000, β = 50%, and when the number of reciprocations n is 10,000. β = 9%. Therefore, the number of reciprocations n is 1000 or more, preferably 10,000 or more.

  If the number of round trips n is 10000 or more, the time difference T ′ of the relay delay time to be measured is about several seconds, so that the time difference T ′ of the delay time can be accurately measured by software.

Moreover, by taking the difference DMR (n-1) reception time t ₂ which has received the 'from DMM (0) reception time t _1, which has received the' error due processing time of the software included in the reception time t ₂ ' The error due to the processing time of the software included in the reception time t ₁ 'is subtracted from Therefore, the error included in T ′ (= t ₂ ′ −t ₁ ′) is a variation of the software processing time, T _{s in the} above equation (3) is reduced, and the error ratio β is reduced.

  As described above, the number of round trips n is set so that the error due to the software processing time falls within an allowable range with respect to the actual relay delay time.

As described above, in the present invention, in order to measure the round-trip relay delay time between the relay devices A and B, the relay delay time can be measured by software by reciprocating the DMM / DMR between the relay devices A and B. By dividing the time difference T ′ of the relay delay time obtained by reciprocating the DMM / DMR between the relay devices A and B by the number of reciprocations n, the relay delay time T _d is Calculated.

As a result, the relay delay time can be accurately measured by software, the relay device A has a transmission line card and a reception line card, and the hardware clock of the transmission line card and the reception line card Even when the hardware clocks are not synchronized, it is possible to accurately measure the relay delay time _Td .

In the present invention, when the first DMM (0) is transmitted from the relay device A, the relay device A receives it internally, measures the reception time t ₁ ′ of the DMM (0), and relays it. Relay by dividing the difference between reception times t ₁ ′ and t ₂ ′ by the number of round trips n after measuring the reception time t ₂ ′ of DMR (n−1) after n round trips between devices A and B The delay time _Td is calculated.

Since the time required for the software reception process when receiving DMM (0) and DMR (n−1) is substantially the same, the reception times t ₁ ′ and t ₂ ′ are shifted by the time required for the software reception process. Therefore, the time difference T ′ of the relay delay time, which is the difference, is almost the same value as the time difference T of the actual relay delay time, and the time difference T ′ of the relay delay time is divided by the number of round trips n to obtain an accurate The relay delay time _Td can be obtained.

Further, by setting the number of times the DMM / DMR is reciprocated between the relay devices A and B to 1000 times or more, the error can be further reduced, and a more accurate relay delay time _Td can be obtained.

  In the above embodiment, the round trip number r is incremented after the received DMR is converted to DMM. However, the present invention is not limited to this, and the round trip number r may be incremented before the DMR is converted to DMM. .

  The present invention is not limited to the above-described embodiments, but is interpreted as embodying all modifications and alternative configurations included in the scope of the basic teachings described in the present specification that can be conceived by those skilled in the art. Should be.

It is a schematic diagram of the measuring system of the relay delay time between relay devices of the present invention. It is a figure explaining the operation | movement of the relay apparatus A of the measuring system of the relay delay time between relay apparatuses of FIG. It is a figure explaining the operation | movement of the relay apparatus A of the measuring system of the relay delay time between relay apparatuses of FIG. It is a figure explaining the frame structure of DMM and DMR used by this invention. It is a figure explaining the measuring method of the relay delay time between the relay apparatuses of this invention. It is a schematic diagram which shows an example of the system which does not have the clock synchronized at the hardware level. It is a figure explaining the measuring method of the relay delay time between the conventional relay apparatuses.

Explanation of symbols

1 Measurement system for relay delay time between relay devices 2 DM control circuit 3 Packet analysis circuit 4 Software processing unit 5 DMR-DMM conversion circuit 6 Increment circuit 7 Software request transmission circuit 8 Transmission side copy circuit 9 Reception side copy circuit 10 DMR discard Circuit 11 First reception time measurement unit 12 Second reception time measurement unit 13 Relay delay measurement unit 14 DM control circuit 15 DMM-DMR conversion circuit A, B Relay device

Claims (18)

A method for measuring a relay delay time between relay devices for measuring a round trip relay delay time between a first relay device and a second relay device,
A method for measuring a relay delay time between relay devices, comprising measuring a relay delay time required for a predetermined number of round trips between the first relay device and the second relay device.   The first relay device and the second relay device are divided by the predetermined number of times of the relay delay time required for the predetermined number of round trips between the first relay device and the second relay device. The method for measuring a relay delay time between relay devices according to claim 1, wherein a round trip relay delay time between the devices is calculated. Transmitting a first frame from the first relay device to the second relay device;
The second relay device receives the first frame, converts the first frame into a second frame, and transmits the second frame to the first relay device;
The first relay device receives the second frame, converts the second frame into the first frame, and transmits the first frame to the second relay device;
By performing the predetermined number of round-trip exchanges between the first frame and the second frame between the first relay device and the second relay device, the first relay device and the second relay device. The method of measuring a relay delay time between relay devices according to claim 1 or 2, wherein the relay delay time required when the predetermined number of round trips between the relay devices is measured. When transmitting the first first frame from the first relay device, the first relay device internally receives and measures the reception time of the first first frame;
The first relay device receives the second frame after the predetermined number of round trips between the first relay device and the second relay device, and the second frame after the predetermined number of round trips Measure the frame reception time,
Based on the difference between the reception time of the second frame after the predetermined number of round trips and the reception time of the first first frame, the round trip between the first relay device and the second relay device is performed the predetermined number of times. 4. The method for measuring a relay delay time between relay devices according to claim 3, wherein the relay delay time is sometimes measured. The first frame and the second frame have a region for holding the number of round trips between the first relay device and the second relay device,
The first relay device converts the received second frame into the first frame, increments the number of round-trips of the area, and transmits the first frame to the second relay device. The method for measuring a relay delay time between relay devices according to claim 3 or 4.   As the first frame and the second frame, ITU-T Y. The method for measuring a relay delay time between relay devices according to any one of claims 3 to 5, wherein DMM and DMR specified in 1731 are used. A system for measuring a relay delay time between relay devices that measures a round trip relay delay time between a first relay device and a second relay device,
The system for measuring a relay delay time between relay devices, wherein the first relay device includes means for measuring a relay delay time required when the first relay device makes a predetermined number of round trips to and from the second relay device.   The first relay device divides a relay delay time required for the predetermined number of round trips between the first relay device and the second relay device by the predetermined number of times. The system for measuring a relay delay time between relay devices according to claim 7, wherein a round trip relay delay time between the relay device and the second relay device is calculated. The second relay device receives a first frame from the first relay device, converts the first frame into a second frame, and converts the second frame to the first relay device. Means to transmit to
The first relay device includes means for receiving the second frame, converting the second frame into the first frame, and transmitting the first frame to the second relay device. 9. The relay delay time between relay devices according to claim 7, wherein the first relay device and the second relay device perform round-trip exchange between the first frame and the second frame a predetermined number of times. Measuring system. The first relay device is
When transmitting the first first frame, it is received internally to measure the reception time of the first first frame,
Receiving the second frame after the predetermined number of round trips between the first relay device and the second relay device, and measuring the reception time of the second frame after the predetermined round trips ,
Based on the difference between the reception time of the second frame after the predetermined number of round trips and the reception time of the first first frame, the round trip between the first relay device and the second relay device is performed the predetermined number of times. 10. The system for measuring a relay delay time between relay devices according to claim 9, which measures the relay delay time that is sometimes required. The first frame and the second frame have a region for holding the number of round trips between the first relay device and the second relay device,
The first relay device converts the received second frame into the first frame, increments the number of round-trips of the area, and transmits the first frame to the second relay device. The system for measuring a relay delay time between relay devices according to claim 9 or 10.   As the first frame and the second frame, ITU-T Y. The method for measuring a relay delay time between relay devices according to claim 9, wherein DMM and DMR specified in 1731 are used.   A relay device comprising means for measuring a relay delay time required for a predetermined number of round trips to and from another relay device.   The means divides the relay delay time required for the predetermined number of round trips with the other relay device by the predetermined number of times, thereby reducing the round trip relay delay time with the other relay device. The relay device according to claim 13 to calculate. The means is
Sending the first frame to the other relay device;
Receiving a second frame from the other relay device, converting the second frame into the first frame, and transmitting the first frame to the second relay device;
By reciprocating the first frame and the second frame with the other relay device for the predetermined number of times, and when reciprocating with the other relay device for the predetermined number of times. The relay device according to claim 13 or 14, which measures the relay delay time. The means is
When transmitting the first first frame, received inside the means to measure the reception time of the first first frame;
Receiving the second frame after the predetermined number of round-trips with the other relay device, and measuring the reception time of the second frame after the predetermined number of round-trips;
The relay delay time required for the predetermined number of round trips to the other relay device based on the difference between the reception time of the second frame after the predetermined round trip and the reception time of the first first frame. The relay device according to claim 15 to be measured. The first frame and the second frame have a region for holding the number of round-trips with the other relay device,
The means converts the received second frame into the first frame, increments the number of round-trips of the area, and transmits the first frame to the other relay device. The relay equipment described.   As the first frame, ITU-T Y.T. The relay device according to claim 15, wherein a DMM defined in 1731 is used.

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