JP2005039572A - Analysis method and device for reception packet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow packets arriving in a reverse reception order to be quantitatively analyzed and classified in the case that packets arrives at a reception terminal in a reverse arrival order. <P>SOLUTION: Fluctuation information obtained from sequence numbers or reception timestamps of reception packets and an average value of reception intervals of all reception packets is used to classify the reception packets into normal packet, delay packets, loss packets, and disordered packets, and the number of packets in each classification is counted up. In order to execute this processing, packets having sequence numbers and transmission times written therein are transmitted from a transmission terminal 2A (19A). When receiving the packets (43A) through an IP network, a reception terminal 5A gives reception timestamps to the packets and arranges the packets in the order of sequence numbers and gives a series of memory numbers to the packets. AN average reception interval is calculated from time differences (reception intervals) between reception timestamps and transmission times and calculates fluctuation from reception intervals of the packets and the average reception interval and classifies and stores the packets by values of fluctuation as mentioned above. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a received packet analysis method and apparatus capable of quantitatively measuring and analyzing transmission quality in a LAN (private information communication network) or WAN (wide area network) communication network. More specifically, it does not provide a new received packet analysis method and apparatus suitable for measuring and analyzing packet fluctuations, delays, out-of-order, etc., in communications performed over IP (Internet Protocol) networks. It is what.

  In response to communication quality complaints from users using the network, understand the quality of the IP packet network (packet loss rate, delay, packet fluctuation time, IP packet path) for each call that is subject to quality complaint In addition, verification / isolation of failure / congestion points of the IP packet network is performed.

In voice packet transmission in a LAN (local information communication network) or WAN (wide area network) network environment, the packet arrival order may be reversed and reach the receiving terminal. In such a case, it is necessary for the voice terminal to temporarily store data using a reception buffer, and to perform a process of rearranging the received packets in the correct order and the correct time interval. Although it is possible to measure and analyze received packet delay, jitter and loss (missing lost packets), it is impossible to quantitatively analyze packets whose reception order has been reversed. It was difficult to design a terminal reception buffer.
JP 2002-64545 A

  The problem to be solved is that when the arrival order of the packet is reversed and reaches the receiving terminal, the packet whose reception order is reversed cannot be quantitatively analyzed. It is difficult to design the reception buffer.

  The main feature of the present invention is to solve the above problems. For this purpose, received packets are classified into normal packets, delayed packets, lost packets, and out-of-order packets using fluctuation information obtained from the average number of received packet sequence numbers and received time stamps and the received intervals of all received packets. And the number of each was added up.

  According to the received packet analysis method and apparatus of the present invention, it is possible to analyze the reception status of received packets from the network in more detail than before, and to help the design and analysis of the voice reception buffer of the network terminal.

  Using the fluctuation information obtained from the received packet sequence number and reception time stamp and the average value of the reception intervals of all received packets, the received packets are classified into normal packets, delayed packets, lost packets, and out-of-order packets. The number of items was counted.

  FIG. 1 is a block diagram of an embodiment of the present invention. A transmission terminal 2A and a reception terminal 5A are connected via the IP network 1. The transmission terminal 2A includes a transmission parameter setting unit 11A and a packet transmitter 12A. The transmission parameter setting unit 11A passes items such as a packet size (number of bytes), a packet transmission period, a packet transmission cycle, and a packet configuration as parameters at the time of transmission to the packet transmitter 12A as a transmission parameter signal 18A. The packet transmitter 12A writes the transmission time and sequence number, and sends the packet transmission signal 19A to the receiving terminal 5A via the IP network 1.

  The receiving terminal 5A includes a packet receiver 41 and a packet analyzer 42. The packet receiver 41 receives the packet transmission signal 19A from the transmission terminal 2A as the packet reception signal 43A via the IP network 1. A reception time stamp indicating the reception time is given to the packet, and the packet 72 with the reception time stamp is passed to the packet analyzer 42. In the packet analyzer 42, using the fluctuation information obtained from the sequence number of the received packet, the reception time stamp, and the average value of the reception intervals of all the received packets, the received packet is converted into a normal packet, a delayed packet, a lost packet, an out of order. Classify into packets and count the number of each.

  FIG. 2 shows a circuit configuration of the transmission terminal 2A. The packet transmitter 12A includes a transmission packet creation unit 23A, a packet transmission unit 25A, a sequence number issuing unit 27A, and a transmission timer unit 29A.

  The transmission packet creation unit 23A receives a time signal 31A indicating a transmission time from the transmission timer unit 29A and a sequence number instruction signal 35A from the sequence number issuing unit 27A. The transmission packet creation unit 23A, in accordance with the instruction of the transmission parameter signal 18A received from the transmission parameter setting unit 11A, items such as packet size (number of bytes), packet transmission period, packet transmission cycle, packet configuration, transmission time, and sequence number And the transmission packet 32A is passed to the packet transmission unit 25A. The packet transmitter 25A transmits the packet transmission signal 19A to the receiving terminal 5A via the IP network 1. This transmission completion is notified to the sequence number issuing unit 27A as a packet transmission completion signal 33A. The sequence number issuing unit 27A increments the sequence number by one.

  FIG. 3 shows a circuit configuration of the receiving terminal 5A. The receiving terminal 5 </ b> A includes a packet receiver 41 and a packet analyzer 42. The packet receiver 41 includes a packet receiving unit 51, a reception time stamp adding unit 52, and a reception timer unit 53. The packet analyzer 42 includes a sequence number reading unit 55, a memory number giving unit 56, a reception interval fluctuation measuring unit 57, a packet classification unit 58 and a memory 59.

  The packet receiving unit 51 receives the packet transmission signal 19A from the transmission terminal 2A via the IP network 1 as the packet reception signal 43A via the IP network 1, and passes the packet transmission signal 19A to the reception time stamp giving unit 52 as the reception packet 71. The reception time stamp giving unit 52 receives the time signal 73 from the reception timer unit 53, gives a reception time stamp indicating the reception time to the received packet 71, and receives the packet analyzer 42 as a reception time stamped packet 72. To pass.

  In the packet analyzer 42, the sequence number reading unit 55 receives the packet 72 with the reception time stamp and reads the sequence number issued by the transmission terminal 2A. If the sequence number is missing, the packet number is lost as a packet loss (packet loss). If the sequence number is switched, the sequence number is rearranged in order, and the memory number giving unit 56 as a packet 74 after reading the sequence number. Send to. The memory number assigning unit 56 assigns a series of memory numbers to the packet 74 after reading the sequence number, and passes it to the reception interval fluctuation measuring unit 57 as the packet 75 after giving the memory number. The lost packet (lost packet) is not included in the packet 75 to which the series of memory numbers are assigned.

  The reception interval fluctuation measurement unit 57 that has received the packet 75 after the memory number is given, as packet fluctuation data 76, fluctuation information obtained from the sequence number of the received packet, the reception time stamp, and the average value of the reception intervals of all the received packets. It is passed to the packet classification unit 58. The packet classification unit 58 uses the packet fluctuation data 76 to classify the received packets into normal packets, delayed packets, lost packets (lost packets), out-of-order packets, and lost packets detected by the sequence number reading unit 55, Count the number of each. The totaled result is sent to and stored in the memory 59 as packet classification data 77, and is read out as necessary.

FIG. 4 is a packet sequence diagram showing the relationship between the received packet sequence number i, the received time stamp rt _i , and the memory number m in the packet 75 after being given a series of memory numbers. The sequence number i of the received packet is assigned by the transmitting terminal 2A from 1 to N, but 3, 7 and 8 are missing, and it can be seen that it is a lost packet (lost packet). The reception time stamp rt _i represents the reception time of each received packet. The memory number m is given a series of numbers 1 to M in the order of received packets assigned with sequence numbers 1 to N excluding lost packets.

FIG. 5 is a fluctuation determination diagram showing a criterion for determining temporal fluctuation of a received packet. This determination is made by the packet classification unit 58 based on the packet fluctuation data 76 obtained by the reception interval fluctuation measurement unit 57. The classification of received packets with memory numbers 1, 2, and 3 indicated by bold lines is illustrated. The received packet with the memory number 1 is determined as a normal packet because the fluctuation δrt _{1 of the} reception interval is in the range of the classification number n = 0 (normal packet). The received packet with memory number 2 has a receiving interval fluctuation δrt _{2 in} the range of classification number n = 1 ≧ 1 (delayed packet), and is determined to be a delayed packet. The received packet with the memory number 3 has a reception interval fluctuation δrt _{3 in} the range of the classification number n = −1 ≦ −1 (delayed packet), and is determined to be a delayed packet.

The reception interval fluctuation δrt _i , reception interval Δrt _i , average reception interval Δrt _ave , and packet transmission cycle T _{0 in} FIG. Difference between the packet m and m + 1 of the memory number m is adjacent, and received time stamp rt m _{+ 1} of the larger m + 1 of the memory number, and the reception time stamp rt _m small m of memory number The reception interval Δrt _{m + 1} is obtained from the equation (1) for memory numbers m = ₁ to M (m ≧ 1).
Δrt _{m + 1} = rt _{m + 1} −rt _m (1)

The reference time for the analysis of the expression (1) is the packet with the smallest sequence number i (i = 1 in the example shown) among the received packets, that is, the reception time of the memory number m = 1. is the time of the stamp rt _1. This is the reference packet (m = 1). The average of the reception intervals Δrt _{m + 1} obtained from the equation (1) is obtained for all received packets (m = 2 to M) excluding the reference packet, and the average reception interval Δrt _ave is obtained from the equation (2). Here, Σ represents the sum of m = 1 to M−1.
Δrt _ave = {1 / (M−1)} ΣΔrt _{m + 1} (2)

This average reception interval Δrt _ave becomes a value close to the packet transmission period T ₀ when there is no problem such as packet delay or packet loss during packet transmission, and when any problem occurs, the packet transmission period T _The value is far from _zero . Therefore, by calculating the average reception interval Δrt _ave , it is possible to roughly grasp the packet transmission status between the transmission terminal 2A and the reception terminal 5A.

For all received packets excluding the reference packet (m = 1), the fluctuation δrt _{m + 1} of the reception interval, which is the difference between each reception interval Δrt _{m + 1} and the average reception interval Δrt _ave , is obtained by equation (3). .
δrt _{m + 1} = Δrt _{m + 1} −Δrt _ave (3)

The classification number n is obtained by applying the fluctuation δrt _{m + 1} of the reception interval obtained in Expression (3) to Expression (4).
_{nT 0 -T 0/2 <δrt} m + 1 ≦ nT 0 + T 0/2 (4)
Here, when obtaining the n = 0, i.e., when the _{-T 0/2 <δrt m +} 1 ≦ T 0/2, is determined to be normal packets.
n = determined as a delayed packet when a positive integer is obtained. For example, when n = 1,
_{T 0/2 <δrt m +} 1 ≦ 3T 0/2
When n = a negative integer is obtained, it is determined that the packet is out of order. For example, when n = -1,
_{-3T 0/2 <δrt m +} 1 ≦ -T 0/2
The n classification is executed by the packet classification unit 58, and the number of packets for each classification is counted. Packets received in an order reverse to the correct order (out-of-order packets) can also be analyzed quantitatively.

  6 and 7 are flowcharts showing the flow of operations of the packet analyzer 42. When the analysis operation of the received packet is started, the packet 72 with the reception time stamp from the reception time stamp adding unit 52 is accepted (S1, S2Y, FIG. 6). The sequence number i assigned by the transmitting terminal 2A is read and arranged in the order of the numbers (S3). If there is an omission in the aligned sequence number i, it is determined that the packet is lost (S4Y). If there is no packet loss (S4N), a series of memory numbers m are assigned to each received packet (S5). The value of the last memory number M is the number of packets received in the past.

Therefore, the reception interval Δrt _{m + 1} is obtained from the equation (1) for memory numbers m = ₁ to M (m ≧ 1) (S6). Next, the average of the reception intervals Δrt _{m + 1} obtained from the equation (1) is obtained for all the received packets (m = 2 to M) excluding the reference packet (m = 1), and the average reception interval Δrt _ave is expressed by the equation Calculate by (2). Here, Σ represents the sum of m = 1 to M−1 (S7). The fluctuation δrt _{m + 1} of the reception interval, which is the difference between each reception interval Δrt _{m + 1} and the average reception interval Δrt _ave , is obtained by equation (3) (S8). The value of the classification number n is obtained by applying the fluctuation δrt _{m + 1} of the reception interval obtained in Equation (3) to Equation (4) (S9, FIG. 7).

Here, when obtaining the n = 0 (S10, n = 0), i.e., when the _{-T 0/2 <δrt m +} 1 ≦ T 0/2, is determined to be normal packet (S11).
When n = a positive integer is obtained (S10, n> 0), it is determined as a delayed packet (S12). When n = a negative integer is obtained (S10, n <0), it is determined that the packet is out of order (S13). Every n value is added to the previous number (S14), and the process returns to the operation of step S1 for receiving the reception time stamped packet 72. After each n value is added to the previous number (S14), the number of received packets belonging to each n value is calculated and stored (S15). This stored content is read as needed (S16).

  FIG. 8 is a block diagram showing another embodiment of the received packet analysis method and apparatus. Corresponding symbols are given to those corresponding to the components in FIG. A major difference in configuration from FIG. 1 is that the receiving terminal 5B receives the packet reception signal 43B, returns it to the return transmission terminal 2B, and analyzes the packet on the transmission terminal 2B side. Therefore, the burden on the receiving terminal 5B can be reduced, and the transmission and reception time standards are the same. Therefore, the time measurement accuracy of packet analysis is high, and the transmission timer unit 29A and the reception timer of the first embodiment are used. A feature is that the problem of the time error between the parts 53 does not occur.

  In FIG. 8, a transmitting terminal 2B and a receiving terminal 5B are connected via an IP network 1. The transmission terminal 2B includes a transmission parameter setting unit 11B, a packet transmitter 12B, a packet receiver 66, and a packet analyzer 67. The transmission parameter setting unit 11B passes items such as a packet size (number of bytes), a packet transmission period, a packet transmission cycle, and a packet configuration as transmission parameters to the packet transmitter 12B as a transmission parameter signal 18B. The packet transmitter 12B writes the transmission time and the sequence number, and sends the packet transmission signal 19B to the receiving terminal 5B via the IP network 1.

  The reception terminal 5B includes a reception packet return unit 44. When receiving the packet transmission signal 19B from the transmission terminal 2B via the IP network 1 as the packet reception signal 43B, the reception packet return unit 44 immediately returns the packet transmission signal 45 as the return packet transmission signal 45 to the transmission terminal 2B via the IP network 1. To do. The transmitting terminal 2B that has received this as the return packet reception signal 46 adds a reception time stamp indicating the reception time to the packet using the time signal 31B, and passes the packet 102 with the reception time stamp to the packet analyzer 67. . The packet analyzer 67 uses the fluctuation information obtained from the average value of the reception packet sequence number and reception time stamp and the reception interval of all reception packets to determine whether the reception packet is a normal packet, a delayed packet, a lost packet, or an out of order. Classify into packets and count the number of each.

  FIG. 9 is a circuit configuration diagram of the transmission terminal 2B, which is a component of FIG. Corresponding symbols are given to those corresponding to the components in FIGS. The packet transmitter 12B includes a transmission packet creation unit 23B, a packet transmission unit 25B, a sequence number issuing unit 27B, and a transmission / reception timer unit 29B.

  The transmission packet creation unit 23B receives a time signal 31B indicating a transmission / reception time from the transmission / reception timer unit 29B and a sequence number instruction signal 35B from the sequence number issuing unit 27B. The transmission packet creation unit 23B, in accordance with the instruction of the transmission parameter signal 18B received from the transmission parameter setting unit 11B, items such as packet size (number of bytes), packet transmission period, packet transmission cycle, packet configuration, transmission time, and sequence number And the transmission packet 32B is passed to the packet transmission unit 25B. The packet transmitter 25B transmits the packet transmission signal 19B to the receiving terminal 5B via the IP network 1. This transmission completion is notified to the sequence number issuing unit 27B as a packet transmission completed signal 33B. The sequence number issuing unit 27B increments the sequence number by 1.

  The packet receiver 66 includes a packet receiving unit 81 and a reception time stamp adding unit 82. The packet analyzer 67 includes a sequence number reading unit 85, a memory number giving unit 86, a reception interval fluctuation measuring unit 87, a packet classification unit 88, and a memory 89. The packet receiving unit 81 receives the return packet reception signal 46 from the receiving terminal 5B via the IP network 1 via the IP network 1 and passes it as the received packet 101 to the reception time stamp adding unit 82. The reception time stamp adding unit 82 receives the time signal 31B from the transmission / reception timer unit 29B, adds a reception time stamp indicating the reception time to the reception packet 101, and sets the packet analyzer 67 as a reception time stamped packet 102. To pass.

  In the packet analyzer 67, the sequence number reading unit 85 receives the reception time stamped packet 102 and reads the sequence number issued by the sequence number issuing unit 35B. If the sequence number is missing, the packet number is lost as a packet loss (packet loss). If the sequence number is switched, the sequence number is rearranged in order, and the memory number is added as a packet 104 after reading the sequence number. Send to. The memory number assigning unit 86 assigns a series of memory numbers to the packet 104 after reading the sequence number, and passes it to the reception interval fluctuation measuring unit 87 as the packet 105 after giving the memory number. The lost packet (lost packet) is not included in the packet 105 to which a series of memory numbers are assigned.

  The reception interval fluctuation measuring unit 87 that has received the packet 105 after the memory number is given, as packet fluctuation data 106, fluctuation information obtained from the sequence number of the received packet, the reception time stamp, and the average value of the reception intervals of all the received packets. It is passed to the packet classification unit 88. The packet classification unit 88 uses the packet fluctuation data 106 to classify received packets into normal packets, delayed packets, lost packets (lost packets), out-of-order packets, and lost packets detected by the sequence number reading unit 55, Count the number of each. The aggregation results are sent to and stored in the memory 89 as packet classification data 107, and are read as necessary. The operation flow of the packet analyzer 67 is the same as that shown in the flowcharts shown in FIGS.

The fluctuation of the received packet in the present invention is defined by the equation (3), but the average value δ _mean of the absolute value? Δrt _{m + 1} ? Of the fluctuation δrt _{m + 1} ? Of the reception interval is obtained by the equation (5). May be. This is effective as a means for monitoring and evaluating the state of the network. Here, Σ represents the sum of m = 1 to M−1.
δ _mean = {1 / (M−1)} Σ? δrt _{m + 1} ? (5)

  The present invention can be applied not only to analysis of received packets but also to setting an optimum buffer size for fluctuations in received packets in an IP telephone apparatus using an IP network.

It is the block diagram which showed the Example of the analysis method and apparatus of a received packet. Example 1 FIG. 2 is a circuit configuration diagram of a transmission terminal that is a component of FIG. FIG. 2 is a circuit configuration diagram of a receiving terminal that is a component of FIG. FIG. 5 is a packet sequence diagram showing the relationship between the sequence number, time stamp, and memory number of a received packet. It is the fluctuation determination figure which showed the reference | standard for determining the temporal fluctuation of a received packet. 2 is a flowchart showing a flow of operation of a packet analyzer included in a receiving terminal which is a component of FIG. 7 is a flowchart showing an operation flow of the packet analyzer included in the receiving terminal which is a component of FIG. 1 together with FIG. 6; It is the block diagram which showed the Example of the analysis method and apparatus of a received packet. (Example 2) FIG. 9 is a circuit configuration diagram of a transmission terminal that is a component of FIG.

Explanation of symbols

1 IP network 2A, 2B transmitting terminal 5A, 5B receiving terminal 11A, 11B transmission parameter setting unit 12A, 12B packet transmitter 18A, 18B transmission parameter signal 19A, 19B packet transmission signal 23A, 23B transmission packet creation unit 25A, 25B packet transmission Section 27A, 27B Sequence number issuing section 29A Transmission timer section 29B Transmission / reception timer section 31A, 31B Timing signal 32A, 32B Transmission packet 33A, 33B Packet transmitted signal 35A, 35B Sequence number instruction signal 41 Packet receiver 42 Packet analyzer 43A, 43B packet reception signal 44 reception packet loopback section 45 loopback packet transmission signal 46 loopback packet reception signal 51 packet reception section 52 reception time stamp addition section 53 reception timer section 55 57 Number reading section 56 Memory number assigning section 57 Reception interval fluctuation measuring section 58 Packet classification section 59 Memory 66 Packet receiver 67 Packet analyzer 71 Received packet 72 Received packet with time stamp 73 Time signal 74 Packet 75 after reading sequence number 75 Packets after giving a memory number 76 Packet fluctuation data 77 Packet classification data 81 Packet receiving section 82 Reception time stamp adding section 85 Sequence number reading section 86 Memory number adding section 87 Reception interval fluctuation measuring section 88 Packet classification section 89 Memory 101 Reception packet 102 receive time-stamped packet 104 sequence number packet 106 packet fluctuation data 107 after packet 105 memory numbering after reading the packet classification data n classification number δrt _{m + 1} received Interval of fluctuations Δrt _{m + 1} reception interval Derutart _ave average reception interval rt _i receive time stamp T ₀ packet transmission cycle

Claims (5)

A packet transmission signal (19A, B) to which a transmission time and a series of sequence numbers are assigned is received via the communication network (1), and the reception is performed from the sequence number and the reception time of the received packet in which the reception time is written. A packet reception interval (Δrt _{m + 1} ) and an average reception interval (Δrt _ave ) which is an average value of the reception intervals are obtained, and a difference between the reception interval (Δrt _{m + 1} ) and the average reception interval (Δrt _ave ) the determined as fluctuation of the reception interval (δrt m + _1), using the values of fluctuation (δrt m + ₁₎ of the reception interval, classifies the received packet normally packets, delayed packets, loss packet, the mis-ordering packets And the method of analyzing received packets by counting the number of each category. A transmission terminal process (2A) for sending a packet transmission signal (19A) with a transmission time and a series of sequence numbers to the communication network (1),
The packet transmission signal (19A) is received as a packet reception signal (43A) via the communication network (1), and the reception time stamped packet (72) is given to the packet reception signal (43A). ) And the reception time stamped packet (72), and from the sequence number and the reception time, the reception interval (Δrt _{m + 1} ) of the reception packet and the reception An average reception interval (Δrt _ave ) that is an average value of the intervals is obtained, and a difference between the reception interval (Δrt _{m + 1} ) and the average reception interval (Δrt _ave ) is obtained as fluctuation of the reception interval (δrt _{m + 1} ). , using the value of fluctuation (δrt m + ₁₎ of the reception interval, classifies the received packet normally packets, delayed packets, loss packet, the mis-ordering packets, each Method for analyzing the received packet to the packet analysis processing so as to aggregate the respective number of classes (42) and a receiving terminal processing including (5A). Receiving terminal processing for receiving a packet transmission signal (19B) as a packet reception signal (43B) via the communication network (1) and sending it to the communication network (1) as a return packet transmission signal (45) (5B)
A packet transmission process (12B) for transmitting the packet transmission signal (19B) to which a transmission time and a series of sequence numbers are assigned to the communication network (1) based on a transmission parameter setting instruction (11B, 18B); The return packet transmission signal (45) is received as the return packet reception signal (46) via the communication network (1), the reception packet (101) is obtained, and the reception time is given to the reception packet (101). A packet reception process (66) for providing a packet (102) with a reception time stamp by giving the packet (102) with the reception time stamp, and receiving the packet (102) from the sequence number and the reception time reception interval of 101) (Δrt _{m + 1)} and the average reception interval is an average value of the reception interval (Δrt _ave Look, the obtains the difference between the reception interval (Δrt m + ₁₎ and the average reception interval (Δrt _ave) as fluctuation of the reception interval (δrt m + _1), the reception interval fluctuation of (δrt m + ₁₎ And a packet analysis process (67) that uses the value to classify the received packet into a normal packet, a delayed packet, a lost packet, and an out-of-order packet, and total the number of each class. (2B) A received packet analysis method. A transmission terminal means (2A) for sending a packet transmission signal (19A) with a transmission time and a series of sequence numbers to the communication network (1);
The packet transmission signal (19A) is received as a packet reception signal (43A) via the communication network (1), and the reception time stamped packet (72) is given to the packet reception signal (43A). ) And the reception time stamped packet (72), the reception interval (Δrt _{m + 1} ) of the reception packet and the reception from the sequence number and the reception time. An average reception interval (Δrt _ave ) that is an average value of the intervals is obtained, and a difference between the reception interval (Δrt _{m + 1} ) and the average reception interval (Δrt _ave ) is obtained as fluctuation of the reception interval (δrt _{m + 1} ). , using the value of fluctuation (δrt m + ₁₎ of the reception interval, classifies the received packet normally packets, delayed packets, loss packet, the mis-ordering packets, each Packet analyzing means adapted to aggregate the respective number of classes (42) and the analyzer of the received packet containing the receiving terminal means (5A) as a component containing Receiving terminal means for receiving the packet transmission signal (19B) as a packet reception signal (43B) via the communication network (1) and sending it as a return packet transmission signal (45) to the communication network (1) (5B)
Based on a transmission parameter setting instruction (11B, 18B), packet transmission means (12B) for transmitting the packet transmission signal (19B) to which a transmission time and a sequence number are assigned to the communication network (1) The return packet transmission signal (45) is received as the return packet reception signal (46) via the communication network (1), the reception packet (101) is obtained, and the reception time is given to the reception packet (101). A packet receiving means (66) for giving a packet (102) with a reception time stamp by giving the packet (102) with the reception time stamp, and receiving the packet (102) from the sequence number and the reception time reception interval of 101) (Δrt _{m + 1)} and the average reception interval is an average value of the reception interval (Δrt _ave Look, the obtains the difference between the reception interval (Δrt m + ₁₎ and the average reception interval (Δrt _ave) as fluctuation of the reception interval (δrt m + _1), the reception interval fluctuation of (δrt m + ₁₎ Transmitting terminal means including packet analysis means (67) for classifying the received packets into normal packets, delayed packets, lost packets, and out-of-order packets using values, and counting the number of each of the classifications Received packet analyzer including (2B) as component

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