JP5696032B2 - Content reception amount estimation apparatus and program - Google Patents

Description

  The present invention relates to a content reception amount estimation apparatus and program, and in particular, in a system for distributing content data via a network, a content reception amount estimation apparatus and program for estimating the amount of data received by a terminal side in time series About.

  With the progress of network technology in recent years, applications that handle stream data that transmits and receives various data via a network have appeared. In particular, the spread of video services is remarkable, and applications that handle VoD and stream data have appeared. In particular, the spread of video services has been remarkable, and various types of applications such as VoD and streaming services have appeared. However, in applications that handle these stream data, generally, the received data is accumulated in the reproduction buffer, and after a certain amount of buffer is accumulated, the data is sequentially extracted from the reproduction buffer and reproduced. There are many.

  In such an application, the user's quality of experience can be improved when the playback buffer is not interrupted. On the other hand, if the playback buffer is frequently depleted and the data passed is not continuous, the quality of experience of the user is degraded.

In view of such a situation, estimating the state of the reproduction buffer from outside the reproduction program in the receiving terminal and estimating how the data is read from the reproduction buffer is an evaluation of the user experience quality. It is an important element.

On the other hand, in order to estimate the state of the reproduction buffer, it is important to appropriately evaluate when and how much data transmitted from the server has arrived and accumulated in the reproduction buffer.

  As a protocol used when transferring data from the server, both UDP (User Datagram Protocol) and TCP (Transmission Control Protocol) are used. Each transfer protocol has the following characteristics.

  Although UDP can send data at an arbitrary data rate from the transmission side, it must detect and retransmit the packet loss on the transfer path from the application. Since UDP is a protocol that does not relate to packet order reversal or loss, the amount of data received is determined by the cumulative amount of packets that arrive in principle, except for retransmission packets.

  TCP, on the other hand, confirms whether each data packet has arrived at the client, and is a protocol that has retransmission rate control for unarrived packets and transmission rate control by window control. It is possible to handle the reversal and packet loss without concern (for example, see Non-Patent Document 1).

RFC793: Transmission control Protocol.

  However, for flows that perform data communication using TCP, only the packet layer information is used, information such as retransmission packets due to order reversal or loss is reconstructed, and the time series of data reception amount passed to the application is changed. It was difficult to estimate. Therefore, the data reception status on the receiving terminal for the transmission data from the data distribution server and the status of accumulation / reading from the playback buffer / reading from the playback buffer are appropriate using only packet layer information from outside the playback device. It was difficult to grasp the state of the playback buffer along the time series.

  The present invention has been made in view of the above points, and is a content reception amount estimation device capable of estimating the amount of received bytes in a terminal by appropriately processing data packets and ACK packets or data packets. And to provide a program.

In order to solve the above problems, the present invention provides a system including a content data distribution server that distributes content data via a network and a terminal that receives the content data received from the distribution server. A content reception amount estimation device that estimates a reception data amount of content data at a time,
A packet that acquires packet information of a data packet transmitted from the distribution server via the network and a reception confirmation response packet transmitted to confirm reception from the terminal, and stores the packet information together with the acquired time information in a storage unit Information acquisition means;
In addition to the reception time of the packet information stored in the storage means, the sequence number that increases by 1 for each byte of data, the reception confirmation response number, and the packet size, if it can be acquired, partial reception is confirmed. A reception amount estimation means for estimating the amount of content data received by the terminal at each time using a partial reception confirmation response number that is a sequence number of a start point and an end point of the range;
Have
The reception amount estimation means includes :
Calculates a difference from a value obtained by subtracting the maximum number of bytes received from the continuous to the sequence number of the received packet 1 subtraction to either state packet by said difference is normally received in time series, unreached It is determined whether there is a packet or a packet loss, the packet information is stored in the storage means according to each state, and the data amount of the packet that has finally arrived to determine the retransmission packet is Means for reading from the storage means and outputting in time series;
After the transmission / reception of the content data is completed, the final sequence number and the sequence number transmitted from the distribution server are obtained using the reception time of the packet information stored in the storage means, the sequence number, and the packet size. When the final sequence number is larger, the processing for storing the sequence number, the arrival time of the packet, and the byte amount in the received amount storage unit is performed for all the sequence numbers. Finally, the received amount storage unit Means for rearranging the data stored in the data in order of reception time, and outputting,
including.

  According to the present invention, from a part of the packet information, the difference between the maximum value of the data range at the previous packet acquisition time and the data range of the newly acquired packet is normally received in time series. In order to determine the content data amount at the packet acquisition time according to the state by determining whether there is an unreachable packet or a packet loss, the reception amount that can be normally received on the receiving side It becomes possible to output.

1 is a system configuration diagram according to an embodiment of the present invention. It is a block diagram of the content reception amount estimation apparatus in one embodiment of this invention. It is a block diagram of the memory | storage part in one embodiment of this invention. It is an example of a packet arrival list update in one embodiment of the present invention. It is a flowchart of operation | movement of the content reception amount estimation apparatus in the 1st Embodiment of this invention. It is an example of the gap list G in the 1st Embodiment of this invention. It is a flowchart of operation | movement of the content reception amount estimation apparatus in the 2nd Embodiment of this invention. It is a flowchart of operation | movement of the content reception amount estimation apparatus in the 3rd Embodiment of this invention. It is a flowchart of operation | movement of the content reception amount estimation apparatus in the 4th Embodiment of this invention. It is a flowchart of operation | movement of the content reception amount estimation apparatus in the 5th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  In the present invention, the time series of the data reception amount is estimated from the packet information of the TCP flow.

  Specifically, for data packets and ACK packets, data is passed to the application on the receiving terminal side by reconstructing and processing information such as the packet layer information such as reverse order edge and retransmission packet due to loss. The quantity is estimated along the time series.

Figure 1 shows a system configuration of an embodiment of the present invention.

  The present invention includes a content data distribution server 10 that distributes content data via a network 30, a reception terminal 20 that receives content data from the distribution server 10, and a data packet from the distribution server 10 and reception terminal 20 via the network 30. , A content reception amount estimation apparatus 100 that acquires an ACK packet and estimates a data reception amount.

  FIG. 2 shows a configuration of a content reception amount estimation apparatus according to an embodiment of the present invention.

  The content reception amount estimation apparatus 100 shown in the figure includes a packet information acquisition unit 110, a storage unit 120, a reception amount estimation unit 130, and a packet discard rate estimation unit 140.

  The packet information acquisition unit 110 acquires packet information transmitted / received via the network 30 and stores it in the storage unit 120.

  The storage unit 120 stores the packet information acquired by the packet information acquisition unit 110. The configuration of the storage unit is shown in FIG. The storage unit 120 includes areas of a gap list G121, a packet arrival list R122, a reception confirmation list S123, a packet data storage unit 124, a packet counter 125, a packet passage time recording unit 126, and a reception amount recording unit 127.

  The gap list G121 records missing numbers and the like when data packets are not continuous. The packet arrival list R122 records packets that have arrived to determine retransmission packets. An example of the packet arrival list is shown in FIG. The reception confirmation list S123 is for detecting duplication of ACK packets. In the packet data storage unit 124, the packet information includes the time at which each packet is received by the packet information acquisition unit 110, a sequence number, a reception confirmation response number, a packet size, a partial reception confirmation response number, and the like. The reception amount recording unit 127 is used for estimating the number of received bytes from the packet series.

  The reception amount estimation unit 130 reads the packet information from the storage unit 120 and estimates the amount of content data received at each time at the reception terminal 20.

  The packet discard rate estimation unit 140 estimates the packet discard rate in the network on the distribution server 10 side and the packet discard rate in the network on the receiving terminal 20 side.

  In TCP, there are a data packet sent from the distribution server 10 and an ACK packet of a reception confirmation response sent from the client (receiving terminal) 20. A data packet has a sequence number recorded in the packet header, and corresponds to offset information indicating where the packet corresponds to data to be transmitted.

  In the ACK packet, a value obtained by adding 1 byte to the number of bytes of data continuously received by the receiving terminal 20 so far is added to the sequence number of the received packet and reported as a reception confirmation response.

The data packet may be retransmitted depending on the communication status. Resend is
1. The data packet was discarded before it arrived at the client;
2. The ACK packet was discarded before it arrived at the server;
There are two possible cases.

Also, considering the possibility of loss at the top and bottom of the location where packet information is acquired,
a. The data packet passed through the packet information acquisition unit 110 but was discarded before the client arrived;
b. The data packet was discarded before passing through the packet information acquisition unit 110;
c. The ACK packet passed through the packet information acquisition unit 110 but was discarded before arrival at the server;
d. The ACK packet was discarded before passing through the packet information acquisition unit 110;
There is a possibility that retransmission of a packet occurs in each discard pattern.

  The packet loss estimation unit 130 matches the data packet observed by the packet information acquisition unit 110 with the ACK packet to determine the possibility of loss at the upper and lower portions of the location where the packet information is acquired in the case of b or d above. Since the packet that has passed through the packet information acquisition unit 110 is not discarded, the amount of data received can be determined with high accuracy. On the other hand, in the case of a and c described above, it causes an error.

  Therefore, it is possible to accurately output the time series of the received amount by utilizing the data packet transmitted repeatedly, the packet that has been acknowledged, and the information if the partial acknowledgment is valid. .

  Each embodiment will be described below.

[First Embodiment]
This will be described based on the configuration of FIG. In the present embodiment, a case where the reception amount is estimated using a data packet transmitted from distribution server 10 and a reception confirmation response packet (ACK packet) transmitted to confirm reception from receiving terminal 20 will be described. To do.

  When the packet information acquisition unit 110 acquires data packets or ACK packets transmitted from the distribution server 10 and the receiving terminal 20, the following processing is performed.

  FIG. 5 is a flowchart of the operation of the content reception amount estimation apparatus in the first embodiment of the present invention.

  Step 101) First, when the packet information acquisition unit 110 acquires a packet, the packet information acquisition unit 110 records the acquired packet information in the packet data storage unit 124 of the storage unit 12. If the acquired packet is a data packet, the process proceeds to step 102, and if it is an ACK packet, the process proceeds to step 121.

  Step 102) The reception amount estimation unit 130 stores the maximum value (latest_data) of the data range that has been continuously received and stored in the memory (not shown), and the data of the packet newly acquired in Step 101 Find the difference in the number of bytes at the beginning of the range (difference gap between packets). Specifically, the maximum number of bytes latest_data received is subtracted from the sequence number seq_no of the packet, and a value obtained by subtracting 1 (gap = seq_no−latest_data−1) is calculated.

  If the difference gap is 0, it means that the packets are continuous. If gap> 0, the packets are not continuous, and the gap value indicates the range where the sequence of packets is separated. . If gap <0, a packet loss has occurred and the packet has been retransmitted.

  Also, latest_data is the maximum size of data that has been received continuously. If all previous packets have been received without omission, latest_data = seq_no + length (packet length). Also, if the previous packet is not delivered because it has been discarded, the latest_data remains updated with the seq_no and length of the previous packet.

Step 103) The reception amount estimation unit 130 sets a value obtained by subtracting 1 from the packet length length of the packet to the sequence number seq_no of the packet in the packet arrival list R122 in the storage unit 120, starting from the sequence number seq_no of the packet. Added value
seq_no + (length-1)
The packet arrival time is recorded for a range having the end point as. If the range has already been recorded, data is added after the corresponding range is reduced or updated so as not to overlap. This is a case where duplicate packets are formed by TCP retransmission control. For example, when an ACK packet is discarded in the network, it is considered that the same data packet is retransmitted. When the retransmission packet is sent, the packet size of the original data packet may be different. For example, 100 to 200 bytes are received at time t1, 301 to 400 bytes are received at time t2, and 150 to 300 bytes are received at time t3. May be reduced as follows after receiving t3.

t1 100 to 149 bytes t2 150 to 300 bytes t3 301 to 400 bytes Step 104) Further, the reception amount estimation unit 130 increments the packet counter N125 (initial value 0) by one.

  Step 105) The reception amount estimation unit 130 proceeds to Step 106 when the difference gap between packets is 0, proceeds to Step 107 when gap> 0, and proceeds to Step 108 when gap <0. .

  Step 106) Value obtained by adding the value obtained by subtracting 1 from the packet length length of the packet to the sequence number seq_no of the packet, the maximum number of bytes received in the memory (not shown) latest_data (latest_data = seq_no + (length−1) ).

  Step 107) If the gap gap between packets is positive (gap> 0), indicating that there is a packet that has not reached the receiving terminal 20 due to loss, order reversal, or the like before arrival of a packet, the gap list G121 is entered. Then, a range with the maximum number of received bytes latest_data + 1 as the start point and the value obtained by subtracting 1 from the sequence number seq_no of the packet as an end point is added. When the received maximum number of bytes latest_data is 1500 and the sequence number seq_no of the packet is 2000, it is updated as shown in FIG.

  Step 108) When packet loss occurs and the packet is retransmitted, the gap gap between the packets is negative (gap <0), and the sequence number seq_no of the packet is included in the gap list G121 If yes, the process goes to Step 109; otherwise, the process goes to Step 110.

  Step 109) From the gap list G121, delete the range starting from the sequence number seq_no of the packet and ending with a value obtained by adding 1 to the sequence number seq_no of the packet from the packet length length of the packet.

  Step 110) When packet loss has occurred and the packet is to be retransmitted and passed through the processing of Step 109 above, but lost again downstream, that is, the difference gap between packets is negative (gap <0), and the sequence number seq_no of the packet is not included in the gap list G121, and the maximum sequence of the ACK packet whose reception has been confirmed so far is the sequence number seq_no of the packet. If it is greater than the number latest_ack_no, the process proceeds to step 111, and if not, the process ends.

  Step 111) If the sequence number seq_no of the packet is not included in the reception confirmation list S123 in the storage unit 120, it is determined that the packet is a retransmission packet, and the packet counter N increased in Step 104 is decreased by 1. (N = N−1), and retransmission packets may be excluded from the loss rate calculation.

  Step 121) In step 101, the reception amount estimation unit 130 refers to the packet data storage unit 124. If the acquired packet is an ACK packet (transmitted from the terminal to the distribution server), the reception confirmation list S123 has received it so far. The maximum sequence number latest_ack_no of the confirmed ACK packet is updated to a value obtained by subtracting 1 from the reception confirmation number of the ACK packet.

  Step 122) If selective ACK (SACK) is included in the ACK packet, the process proceeds to step 123, and if not included, the process is terminated.

  Step 123) The range (start and end sequence numbers) for which partial reception has been confirmed is added to the reception confirmation list S123.

  Step 124) From the packet arrival list R122, it is considered that all the data within the range of the maximum sequence number latest_ack_no confirmed so far has arrived, and the transit time of each data in the packet arrival list R122 is recorded. If not, the process proceeds to step 125, and if it is recorded, the process ends.

  Step 125) Record in the packet arrival list R122 as the passage time of the data for which the arrival of the ACK packet is confirmed.

  Further, the arrival time of the packet arrival list R122 may be the average value of the recorded data packet transit time and the ACK packet, and the network delay with the terminal may be simply corrected.

  The packet loss rate calculation by the packet loss rate estimation unit 140 may be performed in the above-described step 108 and step 111 where the packet loss has occurred, or may be performed after a series of flows is completed.

  The reception amount is estimated using the data packet and the ACK packet by following the above procedure when acquiring each packet. Specifically, the contents of the final packet arrival list R122 are output.

[Second Embodiment]
In this embodiment, an example in which estimation is performed using a data packet will be described.

  FIG. 7 is a flowchart of the operation of the content reception amount estimation apparatus in the second embodiment of the present invention.

  Hereinafter, a description will be given based on the configurations of FIGS. 2 and 3.

  The packet information acquisition unit 110 acquires a data packet transmitted from the distribution server 10, stores it in the packet data storage unit 124, and performs the following processing.

  Step 201) In the packet information acquisition unit 110, if the acquired packet is a data packet, the process proceeds to step 202. If the acquired packet is any other packet, the process passes through.

  Step 202) The packet information acquisition unit 110 stores the data packet transmitted from the distribution server 10 in the packet data storage unit 124, and the reception amount estimation unit 130 receives the data that has been continuously received in the gap list G121 so far. A difference (difference gap between packets) between the maximum value of the range and the number of leading bytes of the data range of the packet newly acquired next to the packet data storage unit 124 is obtained. Specifically, the difference gap subtracts the received maximum number of bytes latest_data stored in a memory (not shown) from the sequence number seq_no of a newly acquired packet stored in the packet data storage unit 124. It is calculated as a value obtained by subtracting 1 (gap = seq_no−latest_data−1).

  Step 203) Also, the reception amount estimation unit 130 adds the value obtained by subtracting 1 from the packet length length of the packet to the sequence number seq_no of the packet, starting from the sequence number seq_no of the packet, in the packet arrival list R122 The packet arrival time is recorded for a range having the end point as. For example, when a packet having a sequence number of 1000 bytes and a packet length of 500 bytes is received at time t1, the time t1 corresponding to the range where the start point is 1000 bytes and the end point is 1500 bytes is recorded in the packet arrival list R122. If the range has already been recorded, the corresponding range is reduced or deleted so as not to overlap, and data is added to the packet arrival list R122.

  Step 204) The reception amount estimation unit 130 further increases the packet counter N (initial value 0) by one.

  Step 205) If the gap gap between the packets obtained in step 202 is 0, the process proceeds to step 206. If gap> 0, the process proceeds to step 207. If gap <0, the process proceeds to step 208.

  Step 206) The reception amount estimation unit 130 updates the received maximum number of bytes latest_data to a value obtained by adding the value obtained by subtracting 1 from the packet length length of the packet to the sequence number seq_no of the packet (latest_data = seq_no + (length -1).

  Step 207) When gap> 0, the reception amount estimation unit 130 sets the maximum number of received bytes latest_data + 1 as the start point in the gap list G121, and the value obtained by subtracting 1 from the sequence number seq_no of the packet as the end point Add the selected range. For example, when latest_data is 1500 bytes and the sequence number of the received packet is 2000 bytes, the range where the start point is 1501 bytes and the end point is 1999 bytes is recorded in the gap list G121.

  Step 208) If the gap gap between the packets is negative and the sequence number seq_no of the packet is included in the gap list G, the reception amount estimation unit 130 proceeds to Step 209, and the sequence number seq_no is If it is not included in the gap list G121, the process proceeds to step 210.

  Step 209) From the gap list G121, the reception amount estimation unit 130 uses the sequence number seq_no of the packet as the start point, and adds the value obtained by subtracting 1 from the packet length length of the packet to the sequence number seq_no of the packet as the end point Delete the range.

  Step 210) When the gap gap between packets is negative and the sequence number seq_no of the packet is not included in the gap list G121, the reception amount estimation unit 130 determines that the packet is a retransmission packet, The packet counter N increased in step 204 may be decreased by 1 (N = N−1), and the retransmitted packet may be excluded from the loss rate calculation.

  The packet loss rate calculation by the packet loss rate estimation unit 140 may be performed in the above-described step 208 and step 210 where the packet loss has occurred, or may be performed after a series of flows is completed.

  By performing the above procedure when acquiring each packet, the final packet arrival list R122 value is output as the reception amount estimation using the data packet.

[Third Embodiment]
In the present embodiment, a case will be described in which the packet information acquisition unit 110 acquires a data packet transmitted from the distribution server 10 and an ACK packet transmitted from the receiving terminal 20 to estimate the reception amount.

  Step 301) The packet information acquisition unit 110 stores the acquired packet data in the packet data storage unit 124. If the acquired packet is a data packet, the process proceeds to step 302, and if it is an ACK packet, the process proceeds to step 321.

  Step 302) The reception amount estimation unit 130 stores the maximum value of the data range that has been stored continuously in the memory (not shown), and the start of the data range of the next newly acquired packet. Find the difference in the number of bytes (difference gap between packets). The gap is calculated as a value obtained by subtracting the maximum number of received bytes last_data from the sequence number seq_no of the packet and subtracting 1.

  Step 303) Also, the reception fee estimation unit 130 adds the value obtained by subtracting 1 from the packet length length of the packet to the sequence number seq_no of the packet, starting from the sequence number seq_no of the packet, in the packet arrival list R122 The packet arrival time is recorded for a range having the end point as. If the range has already been recorded, data is added after the corresponding range is reduced or deleted so as not to overlap.

  Step 304) Further, the packet counter N (initial value 0) is incremented by 1 (N = N + 1).

  Step 305) If the gap difference between packets is 0, the process proceeds to step 306. If gap> 0, the process proceeds to step 307. If gap <0, the process proceeds to step 308.

  Step 306) When gap = 0, the received maximum number of bytes latest_data is updated to a value obtained by adding a value obtained by subtracting 1 from the packet length length of the packet to the sequence number seq_no of the packet.

  Step 307) If the difference between packets is gap> 0, the gap list G121 has a range in which the maximum number of received bytes latest_data + 1 is the starting point, and the value obtained by subtracting 1 from the sequence number seq_no of the packet is the end point. to add.

  Step 308) If the difference between packets is gap <0 and the sequence number seq_no of the packet is included in the gap list G, the process proceeds to Step 309. Otherwise, the process proceeds to Step 310. To do.

Step 309) The packet loss counter loss_A that has occurred in the upstream network is incremented by 1 packet, and from the gap list G121, the sequence number seq_no of the packet is the starting point, and the packet sequence length seq_no is 1 to the packet length length of the packet. Delete the range whose end point is the sum of the subtracted values.

  Step 310) The difference gap between packets is negative (gap <0), the sequence number seq_no of the packet is not included in the gap list G121, and the sequence number seq_no of the packet is If it is larger than the maximum sequence number latest_ack_no confirmed to be received until then, the process proceeds to step 311. Otherwise, no processing is performed. This situation is a case where a packet loss has occurred and is subject to retransmission, and the processing of step 309 has been performed, but the packet loss has occurred again in the downstream network.

  Step 311) When the sequence number seq_no of the packet is not included in the reception confirmation list S123, the packet loss counter loss_B of the downstream network is incremented by one packet. Further, it may be determined that the packet is a retransmission packet, the packet counter increased in step 304 may be decreased by 1, and the retransmission packet may be excluded from the loss rate calculation.

  Step 321) If the acquired packet is an ACK packet (transmitted from the terminal to the distribution server), the reception amount estimation unit 130 sets the maximum sequence number latest_ack_no confirmed so far to the reception confirmation number of the ACK packet. The value is updated by subtracting 1 from.

  Step 322) When the SACK is included in the ACK packet, the process proceeds to Step 323, and when it is not included, the process is terminated.

  Step 323) The reception amount estimation unit 130 adds the range (start point and end point sequence numbers) for which partial reception has been confirmed to the reception confirmation list S123.

  Step 324) From the packet arrival list R122, it is considered that all data within the range below the maximum sequence number latest_ack_no confirmed to be received has arrived, and the transit time of each data in the packet arrival list R122 is recorded. If not, the process proceeds to step 325.

Step 325) The arrival time of the data for which the arrival of the ACK packet is confirmed is recorded in the packet arrival list R122.
The above packet loss rates are given below respectively. In step 309, the packet loss rate estimation unit 140 sets the packet loss rate in the network on the server side from the packet information acquisition unit 110 to a value obtained by dividing the counter loss_A by the packet count N, and from the packet information acquisition unit 140 to the terminal side The packet loss rate in the network is the value obtained by dividing loss_B by the packet count N in step 311.

  The packet loss rate calculation by the packet loss rate estimator 140 may be performed in the above-described step 309 and step 311 in which the packet loss has occurred, or may be performed after a series of flows is completed.

  By performing the above procedure when each packet is acquired, the final packet arrival list R122 value is output as the reception amount estimation using the data packet and the ACK packet.

[Fourth Embodiment]
In the present embodiment, a case will be described in which the packet information acquisition unit 110 estimates a reception amount using a data packet transmitted from the distribution server 10.

  FIG. 9 is a flowchart of the operation of the content reception amount estimation apparatus in the fourth embodiment of the present invention.

  Step 401) When the acquired packet information is a data packet acquired from the distribution server 10, the packet information acquisition unit 110 proceeds to Step 402, and in the case of other packets, the packet information acquisition unit 110 passes the processing.

  Step 402) The reception amount estimation unit 130 stores the maximum value of the data range that has been stored continuously in the memory (not shown) and the number of first bytes of the data range of the newly acquired packet. The difference (gap) is calculated. The difference gap between packets is calculated as a value obtained by subtracting the maximum number of received bytes latest_data from the sequence number seq_no of the packet and subtracting 1.

  Step 403) Further, in the packet arrival list R122, a range in which the sequence number seq_no of the packet is the starting point, and the value obtained by adding the value obtained by subtracting 1 from the packet length length of the packet to the sequence number seq_no of the packet is the end point The packet arrival time is recorded. If the range has already been recorded, data is added after the corresponding range is reduced or deleted so as not to overlap.

  Step 404) Further, the packet counter N (initial value 0) is incremented by 1.

  Step 405) If the difference gap between the packets is 0, the process proceeds to Step 406. If gap> 0, the process proceeds to Step 407. If gap <0, the process proceeds to Step 408.

  Step 406) When gap = 0, the received maximum number of bytes latest_data is updated to a value obtained by adding a value obtained by subtracting 1 from the packet length length of the packet to the sequence number seq_no of the packet.

  Step 407) If gap> 0, add a range to the gap list G starting from the received maximum number of bytes latest_data + 1 and starting from a value obtained by subtracting 1 from the sequence number seq_no of the packet.

  Step 408) When gap <0, if the sequence number seq_no of the packet is included in the gap list G121, the process proceeds to Step 409. Otherwise, the process proceeds to Step 410.

  Step 409) If it is included in the gap list G121, the loss_A is increased by one packet, and from the gap list G121, the sequence number seq_no of the packet is used as the starting point, and the sequence number seq_no of the packet is calculated from the packet length length of the packet. Delete the range that ends with the value obtained by adding 1 subtracted value.

  Step 410) If it is not included in the gap list G121, loss_B is increased by one packet. Further, it may be determined that the packet is a retransmission packet, the packet counter N increased in procedure 1 may be decreased by 1, and the retransmission packet may be excluded from the loss rate calculation.

  The packet loss rate is given by the packet loss rate estimation unit 140 as follows. The packet loss rate in the network on the server side from the packet information acquisition unit 110 is obtained by dividing loss_A by the packet counter N, and the packet loss rate in the network on the terminal side from the packet information acquisition unit is obtained by dividing loss_B by the packet counter N. Calculate by value. Each packet loss rate may be updated each time packet information is acquired, or may be output after the flow is completed.

  By performing the above procedure at the time of obtaining each packet, the value of the final packet arrival list R122 and the packet loss rate obtained by the packet loss rate estimator 140 are used as the reception amount estimation using the data packet and the ACK packet. Output.

[Fifth Embodiment]
In the first to fourth embodiments described above, the state of each packet is held and a large amount of memory is used. Therefore, in this embodiment, a reception amount estimation method that can operate in a memory-saving manner after the flow is completed. To state.

  In the following description, the packet information acquisition unit 110 acquires the passage time t_i and the sequence number x_i of the i-th data packet transmitted from the distribution server 10 and stores them in the packet passage time recording unit 126 of the storage unit 120. . Here, the sequence number indicates a relative value based on the value at the start of the TCP connection.

  FIG. 10 is a flowchart of the operation of the content reception amount estimation apparatus in the fifth embodiment of the present invention.

  Step 501) In the packet information acquisition unit 110, when a data packet is acquired, the following processing is performed, and when other packets are acquired, the processing is passed.

  Step 502) When acquiring the data packet, the packet information acquisition unit 110 records the communication time and sequence number of the packet in the packet passage time recording unit 126.

  Step 503) The above processing is repeated until the flow ends, and when the flow ends, the process proceeds to Step 504.

  Step 504) After the flow is completed, the reception amount estimation unit 130 acquires the maximum sequence number stored in the packet passage time recording unit 126. Thereafter, the following processing is performed in order from the newest time of the packet passage time recording unit.

The maximum sequence number of the flow is set as the initial value of the variable last_seq in the memory (not shown). When the flow sequence number reaches the maximum value of 32 bits (0xFFFFFFFF), returns to 0, and is used repeatedly, it is determined whether it is used repeatedly based on the sequence numbers of the preceding and following packets. Assign a new unused number. In the following processing, the sequence number indicates the newly assigned non-circulating number.

  Step 505) The reception amount estimation unit 130 reads packet information from the packet passage time recording unit 126.

  Step 506) The sequence numbers seq_i and last_seq of the read packet are compared. If last_seq is larger than seq_i, the process proceeds to Step 507. Otherwise, the process ends.

  Step 507) The arrival time, sequence number and byte amount of the packet are stored in the reception amount recording unit 127.

  Step 508) The sequence number last_seq with the largest flow is updated to seq_i.

  Step 509) Steps 505 and after are repeated until all packets have been processed.

  Step 510) Finally, the data stored in the reception amount recording unit 127 is rearranged in chronological order (in the reverse order of the storage time), and the reception amount estimation result is output.

  The operation of the components of the content reception amount estimation device shown in FIG. 2 can be constructed as a program and installed in a computer used as the content reception amount estimation device for execution or distributed via a network. It is.

  The present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the claims.

DESCRIPTION OF SYMBOLS 10 Distribution server 20 Receiving terminal 100 Content reception amount estimation apparatus 110 Packet information acquisition part 120 Storage part 130 Reception amount estimation part 140 Packet loss rate estimation part

Claims (5)

In a system comprising a content data distribution server that distributes content data via a network and a terminal that receives the content data received from the distribution server, the received data amount of the content data at each time at the receiving terminal is estimated. A content reception amount estimation device,
A packet that acquires packet information of a data packet transmitted from the distribution server via the network and a reception confirmation response packet transmitted to confirm reception from the terminal, and stores the packet information together with the acquired time information in a storage unit Information acquisition means;
In addition to the reception time of the packet information stored in the storage means, the sequence number that increases by 1 for each byte of data, the reception confirmation response number, and the packet size, if it can be acquired, partial reception is confirmed. A reception amount estimation means for estimating the amount of content data received by the terminal at each time using a partial reception confirmation response number that is a sequence number of a start point and an end point of the range;
Have
The reception amount estimation means includes :
Calculates a difference from a value obtained by subtracting the maximum number of bytes received from the continuous to the sequence number of the received packet 1 subtraction to either state packet by said difference is normally received in time series, unreached It is determined whether there is a packet or a packet loss, the packet information is stored in the storage means according to each state, and the data amount of the packet that has finally arrived to determine the retransmission packet is Means for reading from the storage means and outputting in time series;
After the transmission / reception of the content data is completed, the final sequence number and the sequence number transmitted from the distribution server are obtained using the reception time of the packet information stored in the storage means, the sequence number, and the packet size. When the final sequence number is larger, the processing for storing the sequence number, the arrival time of the packet, and the byte amount in the received amount storage unit is performed for all the sequence numbers. Finally, the received amount storage unit Means for rearranging the data stored in the data in order of reception time, and outputting,
A content reception amount estimation apparatus comprising: In a system comprising a content data distribution server that distributes content data via a network and a terminal that receives the content data received from the distribution server, the received data amount of the content data at each time at the receiving terminal is estimated. A content reception amount estimation device,
A packet information acquisition means for acquiring a data packet transmitted from the distribution server via the network and storing it in a storage means together with the acquired time information;
The reception amount estimation for estimating the amount of content data received by the terminal at each time using the reception time of the packet information stored in the storage means, the sequence number increasing by one for each byte of data, and the packet size Means,
Have
The reception amount estimation means includes :
Calculates a difference from a value obtained by subtracting the maximum number of bytes received from the continuous to the sequence number of the received packet 1 subtraction to either state packet by said difference is normally received in time series, unreached It is determined whether there is a packet or a packet loss, the packet information is stored in the storage means according to each state, and the data amount of the packet that has finally arrived to determine the retransmission packet is Means for reading from the storage means and outputting in time series;
After the transmission / reception of the content data is completed, the final sequence number and the sequence number transmitted from the distribution server are obtained using the reception time of the packet information stored in the storage means, the sequence number, and the packet size. When the final sequence number is larger, the processing for storing the sequence number, the arrival time of the packet, and the byte amount in the received amount storage unit is performed for all the sequence numbers. Finally, the received amount storage unit Means for rearranging the data stored in the data in order of reception time, and outputting,
A content reception amount estimation apparatus comprising: In a system comprising a content data distribution server that distributes content data via a network and a terminal that receives the content data received from the distribution server, the received data amount of the content data at each time at the receiving terminal is estimated. A content reception amount estimation device,
A packet that acquires packet information of a data packet transmitted from the distribution server via the network and a reception confirmation response packet transmitted to confirm reception from the terminal, and stores the packet information together with the acquired time information in a storage unit Information acquisition means;
In addition to the reception time of the packet information stored in the storage means, the sequence number incrementing by 1 for each byte of data, the reception confirmation response number, and the packet size, if possible, the partial reception confirmation response number Using the received amount estimating means for estimating the amount of content data received by the terminal at each time,
A packet discard rate estimation unit for estimating and outputting a packet discard rate in the network on the server side from the packet information acquisition unit and a packet discard rate in the network on the terminal side from the packet information acquisition unit;
Have
The reception amount estimation means includes :
Calculates a difference from a value obtained by subtracting the maximum number of bytes received from the continuous to the sequence number of the received packet 1 subtraction to either state packet by said difference is normally received in time series, unreached It is determined whether there is a packet or a packet loss, the packet information is stored in the storage means according to each state, and the data amount of the packet that has finally arrived to determine the retransmission packet is Means for reading from the storage means and outputting in time series;
After the transmission / reception of the content data is completed, the final sequence number and the sequence number transmitted from the distribution server are obtained using the reception time of the packet information stored in the storage means, the sequence number, and the packet size. When the final sequence number is larger, the processing for storing the sequence number, the arrival time of the packet, and the byte amount in the received amount storage unit is performed for all the sequence numbers. Finally, the received amount storage unit Means for rearranging the data stored in the data in order of reception time, and outputting,
A content reception amount estimation apparatus comprising: In a system comprising a content data distribution server that distributes content data via a network and a terminal that receives the content data received from the distribution server, the received data amount of the content data at each time at the receiving terminal is estimated. A content reception amount estimation device,
A packet information acquisition means for acquiring a data packet transmitted from the distribution server via the network and storing it in a storage means together with the acquired time information;
The reception amount estimation for estimating the amount of content data received by the terminal at each time using the reception time of the packet information stored in the storage means, the sequence number increasing by one for each byte of data, and the packet size Means,
A packet discard rate estimating unit for obtaining a packet discard rate in the network on the server side from the packet information obtaining unit and a packet discard rate in the network on the terminal side from the packet information obtaining unit;
The reception amount estimation means includes :
Calculates a difference from a value obtained by subtracting the maximum number of bytes received from the continuous to the sequence number of the received packet 1 subtraction to either state packet by said difference is normally received in time series, unreached It is determined whether there is a packet or a packet loss, the packet information is stored in the storage means according to each state, and the data amount of the packet that has finally arrived to determine the retransmission packet is Means for reading from the storage means and outputting in time series;
After the transmission / reception of the content data is completed, the final sequence number and the sequence number transmitted from the distribution server are obtained using the reception time of the packet information stored in the storage means, the sequence number, and the packet size. When the final sequence number is larger, the processing for storing the sequence number, the arrival time of the packet, and the byte amount in the received amount storage unit is performed for all the sequence numbers. Finally, the received amount storage unit Means for rearranging the data stored in the data in order of reception time, and outputting,
A content reception amount estimation apparatus comprising: Computer
The content reception amount estimation program for functioning as each means of the content reception amount estimation apparatus of any one of Claims 1 thru | or 4.

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