JP5767174B2 - Delay variation measuring apparatus, delay variation measuring method, and delay variation measuring program - Google Patents

Description

  The present invention relates to an apparatus, a method, and a program for calculating delay variation indicating the degree of dispersion of delay time for transmission of transmitted and received packets.

  ITU-T Y.M. 1541 and Patent Document 1 describe a technique for calculating a delay variation (IPDV: Internet Protocol Packet Variation) indicating a degree of dispersion of a delay time (IPTD: Internet Protocol Transfer Delay) for transmission of transmitted and received packets. Is disclosed. The delay variation IPDV is calculated as the difference between the upper limit value and the lower limit value of the dispersion range of the delay time IPTD for the transmission of a plurality of transmitted and received packets.

Special table 2003-534715 gazette

  ITU-T Y.M. In 1541 and Patent Document 1, it is conceivable to calculate the delay variation IPDV after collecting the frequency distribution of the delay time IPTD for transmission of a plurality of transmitted and received packets. However, there are problems that the measurement of the delay variation IPDV requires a long time and the real-time property cannot be secured. When the number of classes of the frequency distribution of the delay time IPTD is limited, first, the first class width of the delay time IPTD is set roughly, and then the frequency distribution of the delay time IPTD is set in a wide range including the upper limit value and the lower limit value. After the collection, the first class width of the delay time IPTD is set finely, and then the frequency distribution of the delay time IPTD is collected in the vicinity of the upper limit value and the lower limit value.

  Therefore, in order to solve the above-described problem, the present invention has an object of ensuring real-time performance without requiring a long time in calculating delay variation indicating the degree of dispersion of delay time for transmission of transmitted and received packets. And

  In order to achieve the above object, for transmission of transmitted and received packets, the delay times are registered in the delay time table in ascending or descending order, the upper limit value and lower limit value of the range of delay time dispersion are read from the delay time table, and the upper limit The difference between the value and the lower limit value is calculated, and the delay variation is calculated.

Specifically, the present invention includes a packet transmission unit that transmits a packet, a packet reception unit that receives the packet, a delay time measurement unit that measures a delay time of transmission of the packet, and the delay time measurement unit. the delay time of the transmission of the measured the packet is registered in the delay time table the delay time of the transmission of packets sent and received is registered, updating the delay time table so that the ascending or descending order according to the delay time a delay time table update unit that, the delay time corresponding to the upper limit value and the lower limit of the range of variance of the delay times for transmission of the transmission packet received from the delay time table in which the delay time table updating unit has updated read, calculates a difference between the delay time of the delay time and the lower limit value of the upper limit, packets sent and received delay time variance for the transmission of And delay variation calculation unit that calculates a delay variation indicating a degree, a delay variation measurement device, characterized in that it comprises a.

Specifically, the present invention includes a packet transmission step of transmitting a packet, a packet reception step of receiving the packet, a delay time measurement step of measuring a delay time of transmission of the packet, and the delay time measurement step. the delay time of the transmission of the measured the packet is registered in the delay time table the delay time of the transmission of packets sent and received is registered, updating the delay time table so that the ascending or descending order according to the delay time a delay time table updating step of, delay time corresponding to the upper limit value and the lower limit of the range of variance of the delay times for transmission of the transmission packet received from the delay time table updated in the delay time table update step read, it calculates a difference between the delay time of the delay time and the lower limit value of the upper limit value, which is transmitted and received packetized A delay variation measurement method comprising: the delay variation calculation step of calculating the delay variation indicating the degree of dispersion of the delay time for the transmission of bets, the order.

  According to this configuration, ascending or descending sort tables are created for the delay times of transmitted and received packets, so that a long time can be eliminated in calculating delay fluctuations.

  Further, in the present invention, the delay time table update unit limits the number of registrations in the delay time table to a predetermined number, deletes the delay time of transmission of the oldest transmitted / received packet from the delay time table, The delay variation measuring apparatus is characterized in that a delay time of transmission of packets transmitted and received is registered in the delay time table.

  In the delay time table update step, the present invention limits the number of registrations in the delay time table to a predetermined number, deletes the delay time of transmission of the oldest transmitted / received packet from the delay time table, The delay variation measuring method is characterized in that a delay time of transmission of packets transmitted and received is registered in the delay time table.

  According to this configuration, since a sort table in ascending order or descending order is created for the delay time of packets transmitted / received only at the latest predetermined times, it is possible to eliminate the need for a long time in the calculation of delay variation, and in real time. Sex can be secured.

  In the present invention, the delay variation calculating unit reads the upper limit value and the lower limit value registered in the ascending order or descending order in the delay time table, and the upper limit value before and after the update of the delay time table. When the lower limit value does not change, the delay fluctuation measuring apparatus adopts the delay fluctuation before the delay time table is updated as the delay fluctuation after the delay time table is updated.

  In the delay variation calculating step, the upper limit value and the lower limit value that are registered in the ascending order or descending order in the delay time table are read in the delay time table, and the upper limit value is updated before and after the update of the delay time table. When the lower limit value does not change, the delay variation measurement method is characterized in that the delay variation before the delay time table is updated is adopted as the delay variation after the delay time table is updated.

  According to this configuration, it is not necessary to repeatedly calculate the delay variation when the delay variation becomes stable after a lapse of time from the start of measurement, so that a long time is not required in the calculation of the delay variation. In addition to being able to ensure real-time performance.

  Further, the present invention provides a delay variation measurement program that causes a computer to sequentially execute the packet transmission step, the packet reception step, the delay time measurement step, the delay time table update step, and the delay variation calculation step described above. is there.

  According to this configuration, it is possible to provide a program that can eliminate a long time in calculating the delay variation and can ensure real-time performance.

  The present invention can ensure real-time performance without requiring a long time in calculating a delay variation indicating the degree of dispersion of delay time for transmission of transmitted and received packets.

It is a figure which shows the structure of the delay variation measuring apparatus of Embodiment 1. FIG. It is a figure which shows the process of the delay variation measuring apparatus of Embodiment 1. FIG. It is a figure which shows the process of the delay time measurement of Embodiment 1,2. It is a figure which shows the process of delay time table update and delay fluctuation | variation calculation of Embodiment 1. FIG. It is a figure which shows the structure of the delay variation measuring apparatus of Embodiment 2. It is a figure which shows the process of the delay variation measuring apparatus of Embodiment 2. It is a figure which shows the process of the delay variation measuring apparatus of Embodiment 2. It is a figure which shows the process of delay time table update and delay fluctuation calculation of Embodiment 2. It is a figure which shows the process of delay time table update and delay fluctuation calculation of Embodiment 2.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In the present specification and drawings, the same reference numerals denote the same components.

(Embodiment 1)
The configuration of the delay variation measuring apparatus according to the first embodiment is shown in FIG. The delay variation measuring apparatus 1 includes a transmission parameter input unit 11, a packet transmission unit 12, a packet reception unit 13, a delay time measurement unit 14, a delay time table storage unit 15, a delay time table update unit 16, a delay variation calculation unit 17, and a delay. The variable output unit 18 is configured. The delay variation measuring device 1 transmits a packet to the network 2, receives the packet from the network 2, measures a delay time IPTD of transmission of the packet, repeats these transmission cycles, and calculates a delay variation IPDV. .

  The transmission parameter input unit 11 receives the setting value of the transmission rate and the setting value of the packet length, and based on these setting values, sets the duration of one packet and the interval between adjacent packets (t in FIG. 3). calculate. The packet transmission unit 12 transmits the packet to the network 2. The packet receiving unit 13 receives the packet from the network 2. The delay time measurement unit 14 measures a delay time IPTD of transmission of the packet, as will be described later with reference to FIG.

  The delay time table storage unit 15 stores a delay time table in which delay times IPTD of transmission / reception of transmitted / received packets are registered in ascending order or descending order. As will be described later with reference to FIG. 4, the delay time table update unit 16 registers the delay time IPTD of packet transmission measured by the delay time measurement unit 14 and the delay time table of transmission delay time IPTD of transmitted and received packets. The registration time is registered in ascending order or descending order, and the delay time table is updated.

  As will be described later with reference to FIG. 4, in the delay time table updated by the delay time table update unit 16, the delay variation calculation unit 17 sets an upper limit value and a lower limit value of the dispersion range of the delay time IPTD for transmission of transmitted and received packets. , The difference between the upper limit value and the lower limit value is calculated, and the delay variation IPDV indicating the degree of dispersion of the delay time IPTD for transmission of the transmitted and received packets is calculated. The delay variation output unit 18 outputs a calculated value of the delay variation IPDV.

  The processing of the delay variation measuring apparatus for each transmission cycle is shown in FIG. The delay time measurement process is shown in FIG. The delay time table update and delay variation calculation processing is shown in FIG.

  The delay time measurement unit 14 measures the timing difference value Δtn (step S1). The timing difference value Δtn corresponds to the delay time IPTD and is measured as shown in FIG.

  The upper part of FIG. 3 shows the packet capture timing when the delay variation IPDV of the delay time IPTD is zero. For timings PI0, PI1, PI2, PI3,..., PIn, the interval between adjacent packets does not deviate from the constant value t.

  The lower part of FIG. 3 shows the packet capture timing when the delay variation IPDV of the delay time IPTD is not zero. For timings PR0, PR1, PR2, PR3,..., PRn, the interval between adjacent packets varies from the constant value t.

  The case where the delay variation IPDV of the delay time IPTD is 0 is compared with the case where it is not 0. The difference between the timings PI1 and PR1 is Δt1. The difference between the timings PI2 and PR2 is Δt2. The difference between the timings PI3 and PR3 is Δt3. The difference between the timings PIn and PRn is Δtn.

  Here, the delay time IPTD when the delay variation IPDV of the delay time IPTD is not 0 is obtained by adding the timing difference value Δtn to the delay time IPTD when the delay variation IPDV of the delay time IPTD is 0. Therefore, the variance / variation with respect to the delay time IPTD when the delay variation IPDV of the delay time IPTD is not 0 is equal to the variance / variation with respect to the timing difference value Δtn. Therefore, the delay time measurement unit 14 may measure the timing difference value Δtn or may measure the delay time IPTD. Hereinafter, the delay time measurement unit 14 measures the timing difference value Δtn.

  The delay time table update unit 16 acquires the timing difference value Δtn from the delay time measurement unit 14 (step S2). The delay time table update unit 16 updates the delay time table (step S3). The delay variation calculator 17 calculates the delay variation IPDV (step S4).

  The left side of FIG. 4 shows a delay time table before update. At this time, 100 timing difference values Δtn are registered in ascending order, but may be registered in descending order. The upper limit value of the range of dispersion of the timing difference value Δtn may be, for example, the timing difference value Δtn corresponding to the upper 0.05%. The timing difference value Δtn corresponding to the upper 0.1% may be applied by applying 1541. The lower limit value of the dispersion range of the timing difference value Δtn may be, for example, the timing difference value Δtn corresponding to the lower 0.05%. By applying 1541, the minimum (subscript number 1) timing difference value Δtn may be used.

  The upper limit value of the range of dispersion of the timing difference value Δtn is “+1.46” of the subscript number 99. The lower limit value of the dispersion range of the timing difference value Δtn is “−0.58” of the subscript number 2. The delay variation IPDV is (+1.46) − (− 0.58) = 2.04 (μs).

  The right side of FIG. 4 shows a delay time table after 100 updates. At this point, 200 timing difference values Δtn are registered in ascending order. The upper limit value of the range of dispersion of the timing difference value Δtn is “+1.30” of the suffix number 197. The lower limit value of the dispersion range of the timing difference value Δtn is “−0.50” of the subscript number 4. The delay variation IPDV is (+1.30) − (− 0.50) = 1.80 (μs).

  As described above, since a sort table in ascending order or descending order is created for the delay time IPTD or timing difference value Δtn of the transmitted / received packets, a long time is not required in calculating the delay variation IPDV rather than creating a frequency distribution. be able to.

  However, if the setting value of the transmission rate and the setting value of the packet length are known, the delay variation IPDV can be calculated ex post rather than in real time by obtaining the result of the packet capture timing shown in FIG. The delay variation measuring apparatus 1 according to the first embodiment can be realized by a computer and a program, and the program can be recorded on a recording medium or provided through a network.

(Embodiment 2)
FIG. 5 shows the configuration of the delay variation measuring apparatus according to the second embodiment. The delay variation measuring apparatus 1 includes a transmission parameter input unit 11, a packet transmission unit 12, a packet reception unit 13, a delay time measurement unit 14, a delay time table storage unit 15, a delay time table update unit 16, a delay variation calculation unit 17, a delay The variable output unit 18 and the ring buffer unit 19 are included.

  The second embodiment is the same as the first embodiment with respect to the transmission parameter input unit 11, the packet transmission unit 12, the packet reception unit 13, the delay time measurement unit 14, and the delay variation output unit 18.

  As will be described later with reference to FIGS. 8 and 9, the delay time table update unit 16 limits the number of registered delay time tables to a predetermined number and deletes the delay time IPTD of transmission of the oldest transmitted / received packet from the delay time table. Then, the latest transmission / reception packet transmission delay time IPTD is registered in the delay time table. Accordingly, in the second embodiment, the delay time table storage unit 15 is different from the first embodiment, and a ring buffer unit 19 is added.

  The delay time table storage unit 15 and the ring buffer unit 19 have transmitted / received the latest packet from the latest transmission / reception delay time IPTD before accepting the latest transmission / reception packet delay time IPTD. The delay time IPTD is registered until the packet transmission delay time IPTD. However, the delay time table storage unit 15 registers the delay times IPTD in ascending order or descending order. On the other hand, the ring buffer unit 19 registers the delay time IPTD in time series regardless of the size of the delay time IPTD. Note that the ring buffer unit 19 or a FIFO (First-In First-Out) buffer unit may be applied as means for registering the time-series delay time IPTD.

  As will be described later with reference to FIGS. 8 and 9, the delay fluctuation calculation unit 17 reads the upper limit value and the lower limit value registered in the ascending order or the descending order in the delay time table, and before and after updating the delay time table, When the lower limit value does not change, the delay variation IPDV before the delay time table is updated is adopted as the delay variation IPDV after the delay time table is updated.

  The processing of the delay variation measuring apparatus for each transmission cycle is shown in FIGS. Two types of processing of delay time table update and delay variation calculation are shown in FIGS.

  The delay time measuring unit 14 measures the latest timing difference value Δt (latest) (step S11). The delay time table update unit 16 acquires the latest timing difference value Δt (latest) from the delay time measurement unit 14 (step S12), and acquires the oldest timing difference value Δt (oldest) from the ring buffer unit 19. (Step S13), the oldest timing difference value Δt (oldest) is deleted from the ring buffer unit 19 (Step S14), and the latest timing difference value Δt (latest) is registered in the ring buffer unit 19 (Step S15). .

  The delay variation calculation unit 17 acquires the latest timing difference value Δt (latest) and the oldest timing difference value Δt (oldest) from the delay time table update unit 16 (step S16). Then, the delay variation calculation unit 17 acquires the upper limit value and the lower limit value of the range of dispersion of the timing difference value Δtn from the delay time table storage unit 15 (step S17).

  Here, immediately after steps S16 and S17, when the upper limit value and the lower limit value do not change before and after the update of the delay time table, the delay variation calculation unit 17 performs the post-update of the delay time table. As the delay variation IPDV, the delay variation IPDV before the update of the delay time table may be adopted to calculate in a short time in real time.

  In the process of FIG. 8, the upper limit value and the lower limit value do not change before and after the update of the delay time table. In the process of FIG. 9, as an example in which at least one of the upper limit value and the lower limit value changes before and after the update of the delay time table, the lower limit of the upper limit value and the lower limit value before and after the update of the delay time table. The value changes. In the processing of FIGS. 8 and 9, the delay time table before the update is the same.

  The left side of FIGS. 8 and 9 shows a delay time table before update. As a predetermined number, 100 timing difference values Δtn are registered in ascending order, but may be registered in descending order. The upper limit value of the range of dispersion of the timing difference value Δtn may be, for example, the timing difference value Δtn corresponding to the upper 0.05%. The timing difference value Δtn corresponding to the upper 0.1% may be applied by applying 1541. The lower limit value of the dispersion range of the timing difference value Δtn may be, for example, the timing difference value Δtn corresponding to the lower 0.05%. By applying 1541, the minimum (subscript number 1) timing difference value Δtn may be used.

  The upper limit value of the range of dispersion of the timing difference value Δtn is “+1.46” of the subscript number 99. The lower limit value of the dispersion range of the timing difference value Δtn is “−0.58” of the subscript number 2. The delay variation IPDV is (+1.46) − (− 0.58) = 2.04 (μs).

  First, the process of FIG. 8 will be described. The delay time table updating unit 16 performs a scissors search (binary search) for the insertion position for the latest timing difference value Δt (latest) = − 0.15 (step S18), and the oldest timing difference value Δt (maximum). For (old) = + 1.30, a scissors search (binary search) of registered positions is performed (step S19).

  Then, the delay time table updating unit 16 sets the latest timing difference value Δt (latest) = − 0.15, the timing difference value Δtn = −0.20 of the subscript number 51 before the update, and the subscript number 52 before the update. The timing difference value Δtn = −0.12 is inserted, and the timing difference value Δtn = + 1.30 of the subscript number 97 before the update is deleted as the oldest timing difference value Δt (oldest) = + 1.30. The delay time table is updated (step S20).

  The delay variation calculation unit 17 confirms that Δt (latest) and Δt (oldest) acquired in step S16 are between the upper limit value and the lower limit value acquired in step S17 (YES in step S21 and step S22). ). That is, the delay variation calculation unit 17 confirms that the upper limit value and the lower limit value do not change before and after the update of the delay time table.

  Then, the delay variation calculation unit 17 employs the previous delay variation IPDV = 2.04 (μs) as the current delay variation IPDV (step S23). However, the delay variation calculator 17 may newly calculate the delay variation IPDV as the current delay variation IPDV.

  The right side of FIG. 8 shows a delay time table after one update. As a predetermined number, 100 timing difference values Δtn are registered in ascending order. The upper limit value of the range of dispersion of the timing difference value Δtn is “+1.46” of the subscript number 99. The lower limit value of the dispersion range of the timing difference value Δtn is “−0.58” of the subscript number 2. The delay variation IPDV is (+1.46) − (− 0.58) = 2.04 (μs), and does not change before and after the delay time table is updated.

  Next, the process of FIG. 9 will be described. The delay time table updating unit 16 performs a scissors search (binary search) for the insertion position for the latest timing difference value Δt (latest) = − 0.65 (step S18), and the oldest timing difference value Δt (maximum). For (old) = + 1.30, a scissors search (binary search) of registered positions is performed (step S19).

  Then, the delay time table update unit 16 inserts the latest timing difference value Δt (latest) = − 0.65 on the timing difference value Δtn = −0.60 of the index number 1 before the update, and before the update. The timing difference value Δtn = + 1.30 of the subscript number 97 is deleted as the oldest timing difference value Δt (oldest) = + 1.30, and the delay time table is updated (step S20).

  The delay variation calculation unit 17 obtains Δt (oldest) acquired in step S16 between the upper limit value and the lower limit value acquired in step S17, but Δt (latest) acquired in step S16 is acquired in step S17. It is confirmed that it does not fall between the set upper limit value and lower limit value (NO in step S21 and step S22). That is, the delay variation calculation unit 17 confirms that the upper limit value does not change but the lower limit value changes before and after the update of the delay time table.

  Then, as will be described later with reference to FIG. 9, the delay variation calculating unit 17 newly calculates a delay variation IPDV as the current delay variation IPDV (step S24).

  The right side of FIG. 9 shows a delay time table after one update. As a predetermined number, 100 timing difference values Δtn are registered in ascending order. The upper limit value of the range of dispersion of the timing difference value Δtn is “+1.46” of the subscript number 99. The lower limit value of the dispersion range of the timing difference value Δtn is “−0.60” of the subscript number 2. The delay variation IPDV is (+1.46) − (− 0.60) = 2.06 (μs), and changes before and after the delay time table is updated.

In this way, a sort table in ascending order or descending order is created for the delay time IPTD or timing difference value Δtn of packets transmitted and received only at the latest predetermined time. When the delay variation IPDV becomes stable after a lapse of time from the start of measurement, there is no need to repeatedly calculate the delay variation IPDV. Therefore, in calculating the delay variation IPDV, a long time can be eliminated and real-time performance can be ensured. In steps S18 and S19, a scissors search (binary search) is performed, and the maximum time calculation amount can be set to about O (2log ₂ n + n) with respect to the size n of the delay time table.

  However, if the setting value of the transmission rate and the setting value of the packet length are known, the delay variation IPDV can be calculated ex post rather than in real time by obtaining the result of the packet capture timing shown in FIG. The delay variation measuring apparatus 1 according to the second embodiment can be realized by a computer and a program, and can be recorded on a recording medium or provided through a network.

  A delay variation measuring apparatus, a delay variation measuring method, and a delay variation measuring program according to the present invention include a delay time IPTD as a quality level to be realized for each QoS (Quality of Service) class in an end-to-end communication in an IP network. In addition, the delay variation IPDV can be measured in a short time and in real time.

1: Delay variation measurement device 2: Network 11: Transmission parameter input unit 12: Packet transmission unit 13: Packet reception unit 14: Delay time measurement unit 15: Delay time table storage unit 16: Delay time table update unit 17: Delay variation calculation Unit 18: Delay variation output unit 19: Ring buffer unit

Claims (7)

A packet transmitter for transmitting packets;
A packet receiver for receiving the packet;
A delay time measuring unit for measuring a delay time of transmission of the packet;
A delay time of transmission of the packet in which the delay time measuring unit is measured, as registered in the delay time table the delay time of the transmission of packets sent and received is registered, in ascending order or descending order according to the delay time A delay time table updating unit for updating the delay time table;
A delay time corresponding to the upper limit value and the lower limit of the range of variance of the delay times for transmission of sent and received packets, read from the delay time table in which the delay time table updating unit has updated the delay time of the upper limit value and said calculating a difference between the delay time of the lower limit, the delay variation calculation section that calculates a delay variation indicating the degree of dispersion of the delay time for the transmission of packets sent and received,
A delay variation measuring apparatus comprising: The delay time table update unit limits the number of registrations in the delay time table to a predetermined number, deletes the transmission delay time of the oldest transmitted / received packet from the delay time table, and The delay variation measuring apparatus according to claim 1, wherein a delay time of transmission is registered in the delay time table. The delay variation calculation unit reads the upper limit value and the lower limit value registered in a predetermined order in ascending or descending order in the delay time table, and the upper limit value and the lower limit value change before and after the update of the delay time table. 3. The delay variation measuring apparatus according to claim 2, wherein the delay variation before updating the delay time table is adopted as the delay variation after updating the delay time table when not. A packet transmission step of transmitting a packet;
A packet receiving step for receiving the packet;
A delay time measuring step of measuring a delay time of transmission of the packet;
A delay time of transmission of the packet measured by the delay time measuring step, as registered in the delay time table the delay time of the transmission of packets sent and received is registered, in ascending order or descending order according to the delay time A delay time table update step for updating the delay time table;
A delay time corresponding to the upper limit value and the lower limit of the range of variance of the delay times for transmission of sent and received packets, read from the delay time table updated in the delay time table update step, the delay time of the upper limit value and calculating a difference between the delay time of the lower limit, the delay variation calculation step of calculating the delay variation indicating the degree of dispersion of the delay time for the transmission of packets sent and received,
Are provided in order. In the delay time table update step, the number of registrations in the delay time table is limited to a predetermined number, the transmission delay time of the oldest transmitted / received packet is deleted from the delay time table, and the latest transmitted / received packet The delay variation measuring method according to claim 4, wherein a transmission delay time is registered in the delay time table. In the delay variation calculating step, the upper limit value and the lower limit value registered in the predetermined order in the ascending order or descending order in the delay time table are read, and the upper limit value and the lower limit value change before and after the delay time table is updated. 6. The delay variation measuring method according to claim 5, wherein when not, the delay variation before updating the delay time table is adopted as the delay variation after updating the delay time table.   A delay variation that causes a computer to sequentially execute the packet transmission step, the packet reception step, the delay time measurement step, the delay time table update step, and the delay variation calculation step according to any one of claims 4 to 6. Measurement program.

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