JPWO2016103674A1 - Stream receiving apparatus, communication system, stream transmission timing estimation method, and stream transmission timing estimation program - Google Patents

Abstract

[PROBLEMS] To provide a stream receiving apparatus and the like for estimating the transmission timing of a stream with high accuracy. [Solution] A stream receiving apparatus 10b receives a probe packet in a network that transmits data packets and probe packets, calculates a delay time of the probe packet, and transmits the data packet based on the calculated delay time. Estimate time.

Description

  The present invention estimates the transmission timing of a data packet transmitted in a communication network (hereinafter referred to as “network” in the present application), particularly a streaming packet continuously transmitted over a certain period, such as video. Regarding technology.

In a quality non-guaranteed network, the background traffic can be known by the degree of delay time that occurs due to the difference between the packet transmission time at the transmission side device and the reception time of the packet at the reception side device. That is, when the background traffic increases, the delay time becomes longer. Note that the receiving device can easily know the packet reception time, but it is necessary to estimate the packet transmission time.
On the other hand, in the network, it is important to use the network bandwidth as much as possible in consideration of background traffic and realize video streaming without disturbance or interruption. For this purpose, it is necessary to detect a network band that can be used for packet communication in the network (hereinafter referred to as “available band” in the present application).
There is a technique for estimating an available bandwidth that can be used for packet communication between a plurality of terminals connected by a packet communication network. In this technique, the available bandwidth of the network to be estimated is estimated by transmitting a probe packet.

  Patent Document 1 discloses a technique for transmitting a packet sequence that gradually increases in size at regular intervals, and estimating the available bandwidth based on what number of packets the delay time increases.

  Patent Document 2 builds a model representing the relationship between network load and delay from information indicating whether the type of traffic flowing in the network is video or audio, and shows the distribution of delay states of probe packets actually transmitted. Based on this, a technique for estimating the available bandwidth is disclosed.

  In Patent Document 3, probe packets are transmitted and received between networks, round trip delay and jitter are measured from the results, and buffering time of a streaming packet (hereinafter referred to as “stream” in the present application) is determined based on the measurement results. Disclose technology.

  Patent Document 4 discloses a technique for obtaining a one-way delay of a streaming packet in a network during VoIP (Voice over Internet Protocol) communication.

  In addition, there is Patent Literature 5 as a technique related to measurement using a probe packet.

  Non-Patent Document 1 discloses a technique for estimating an available bandwidth based on the number of packets from which the reception interval exceeds the transmission interval by gradually narrowing the packet transmission interval of a certain size.

JP 2011-142622 A JP 2009-118272 A JP 2005-184580 A JP 2012-160832 A JP 2011-135207 A

Vinay Ribeiro, Rudolf Riedi, Richard Baraniuk, Jiri Navratil and Les Cottrell, "PathChirp: Efficient Available Bandwidth Estimation for Network Paths,", In PAM 2003, 4th Passive and Active Measurement Workshop (6 April 2002).

  The techniques of Patent Document 1 and Non-Patent Document 1 do not disclose a technique for accurately estimating the available bandwidth when background traffic is transmitted intermittently like video. These techniques are based on the premise that the available bandwidth does not fluctuate during transmission of one packet sequence. Therefore, the stream transmission timing cannot be accurately estimated in the available bandwidth that fluctuates and changes in the background.

  The technique of Patent Document 2 cannot be used in a network such as the Internet or a mobile network. In other words, the technique of Patent Document 2 requires information on the physical bandwidth of the target network, whereas the Internet is a collection of networks with different management entities, so generally the information on the physical bandwidth is known. I can't. In addition, since the physical bandwidth of the mobile network changes frequently according to the radio quality between the base station and the terminal, it is difficult to use information regarding the physical bandwidth in the mobile network.

  In the technique of Patent Document 3, in streaming from a transmission device to a reception device, probe packets are transmitted from the reception device to the transmission device in advance to measure round-trip delay and jitter. The technique of Patent Document 3 determines the buffering time of a stream so that jitter can be absorbed and packet loss can be retransmitted. However, in the technique of Patent Document 3, since the delay measurement by the probe packet is performed in advance (before the start of stream transmission), the timing of data (packet) transmission cannot be estimated during stream transmission.

  In the technique of Patent Document 4, the transmitting voice communication device transmits time information instead of voice when the voice to be transmitted is silent, and the receiving voice communication device is one-way based on the received packet time information. Calculate the delay time in minutes. However, the technique of Patent Document 4 is a technique for changing information stored in a packet to be transmitted, and the data transmission timing cannot be estimated.

  The present invention has been made to solve the above problems. The main object of the present invention is to estimate the transmission timing of a stream with high accuracy even when a large amount of data is periodically transmitted.

In order to solve the above problems, the first aspect of the present invention is to
A stream receiving device that receives a probe packet, calculates a delay time of the probe packet, and estimates a transmission time of the data packet based on the calculated delay time in a network that transmits the data packet and the probe packet. .

The second aspect of the present invention is:
A stream receiving device as described above;
A stream transmission device for transmitting data packets and probe packets;
The stream receiving device and the stream transmitting device are communicably connected via a network.
It is a communication system.

The third aspect of the present invention is:
In the network that transmits the data packet and the probe packet, the probe packet is received,
Calculate the delay time of the probe packet,
Estimate the transmission time of the data packet based on the calculated delay time,
This is an estimation method.

The fourth aspect of the present invention is:
A program that causes a computer to execute a method of receiving a probe packet in a network that transmits the data packet and the probe packet, calculating a delay time of the probe packet, and estimating a transmission time of the data packet based on the calculated delay time Is a recording medium for storing.

  According to the present invention, even when a large amount of data is periodically transmitted, the transmission timing of the stream can be estimated with high accuracy.

It is a figure which shows the structural example of the communication system which concerns on the 1st Embodiment of this invention. It is a sequence diagram explaining an example of operation | movement of the stream transmission part in the 1st Embodiment of this invention, and a stream receiving part. It is a flowchart explaining an example of operation | movement of the probe transmission part and timing estimation part in the 1st Embodiment of this invention. It is a sequence diagram explaining an example of the change of the delay time of the video packet and probe packet in the 1st Embodiment of this invention. It is a figure explaining the relationship between the transmission time of a probe packet, and delay time. It is a figure which shows the structural example of the communication system which concerns on the 2nd Embodiment of this invention. It is a figure explaining an example of the packet sequence for band estimation. It is a graph explaining the relationship between the probe packet size and the delay time in the available bandwidth estimation. It is a figure explaining the relationship between the probe packet size at the time of video stream transmission, and delay time. It is a figure which shows the structural example of the stream receiver which concerns on the 3rd Embodiment of this invention. It is a figure which shows the structural example of the information processing apparatus for implement | achieving each embodiment of this invention.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings schematically show the configuration of the embodiment of the present invention. Furthermore, the embodiment of the present invention described below is an example, and can be appropriately changed within a range in which the essence is the same.

<First embodiment>
(Communications system)
A configuration of the communication system 100 according to the first embodiment of the present invention will be described. As shown in FIG. 1, the communication system 100 includes a stream transmission device 10, a stream reception device 20, and relay devices 5a and 5b. The stream transmission device 10 includes a stream transmission unit 1 and a probe transmission unit 2. The stream reception device 20 includes a stream reception unit 3 and a timing estimation unit 4.

  The stream transmission unit 1 and the probe transmission unit 2 are communicably connected to the relay device 5a. The stream receiver 3 and the timing estimator 4 are communicably connected to the relay device 5b. Further, the relay device 5a and the relay device 5b are also connected. The stream transmitted by the stream transmission unit 1 is sent to the stream reception unit 3 via the relay devices 5a and 5b. The probe packet transmitted by the probe transmission unit 2 is also transmitted to the timing estimation unit 4 via the relay devices 5a and 5b.

  The stream transmission unit 1 transmits a stream. The stream transmission unit 1 encodes video captured by a camera (not shown) connected to a computer (not shown) with a codec such as H.264, and adds an RTP (Real-time Transport Protocol) header. To create an RTP packet. Then, the stream transmission unit 1 transmits the created RTP packet to the stream reception unit 3. The video stream is configured by collecting a plurality of still image frames (hereinafter referred to as “frames”) that are the basis of a moving image. The frames are continuously displayed, thereby realizing a moving image for the user.

  When it is desired to shorten the waiting time until the video is displayed by the stream receiving unit 3, such as when delivering live video, transmission processing is performed in units of frames. That is, when the stream transmitting unit 1 acquires data for one frame from the camera, the stream transmitting unit 1 repeats the process of encoding and transmitting the acquired frame for each frame. When the number of frames transmitted by performing this process every second is fps (frames per second), this process is performed at 1 / fps (= a) intervals, and frames are transmitted at this time interval (a). (See FIG. 2). At this time, as conceptually shown in FIG. 2, the data size of each frame changes depending on the set value of the bit rate, the type of the frame, the size of the difference from the previous and subsequent frames, and the like. In some cases, it is sent separately.

  The probe transmitter 2 transmits a probe (test) packet for estimating the transmission timing of the stream. The probe transmission unit 2 transmits a probe packet of a certain size to the timing estimation unit 4 at regular time intervals, for example. The probe packet transmission interval may be, for example, an interval of 1 millisecond, but is not limited thereto. As the transmission interval is reduced, the amount of probe packet data is increased, and the accuracy of timing estimation is improved. Therefore, the timing estimation unit 4 may change the transmission interval according to the required accuracy. In order to improve the accuracy of timing estimation, the probe packet transmission interval is preferably a fixed interval, but it may not be a fixed interval. Since the load on the network increases as the probe packet size increases, it is desirable to make the size as small as possible. The probe transmitter 2 inserts (adds) the transmission time of the probe packet into the payload of the probe packet to be transmitted.

  On the stream receiving device 20 side, the stream receiving unit 3 receives a stream. The stream receiving unit 3 receives the video stream transmitted from the stream transmitting unit 1 and analyzes the RTP packet. Thereafter, the stream receiving unit 3 displays the video on a display (not shown) connected to the computer by decoding the received video stream based on a predetermined video codec.

  The timing estimation unit 4 estimates the stream transmission timing based on the time when the probe packet transmitted from the probe transmission unit 2 is received and the transmission time included in the probe packet.

  The relay devices 5a and 5b are router devices that relay streams and probe packets. The relay apparatuses 5a and 5b are connected by a WAN (Wide Area Network) such as the Internet. On the other hand, the stream transmitting device 10 and the relay device 5a, or the stream receiving device 20 and the relay device 5b are connected by a LAN (Local Area Network).

  The configuration of the present embodiment is an example, and the present invention is not limited to this.

  Both the stream transmission unit 1 and the probe transmission unit 2 may be mounted in the same device, or may be individual devices. Both the stream receiver 3 and the timing estimator 4 may be mounted in the same device, or may be individual devices.

  In the communication system 100 described above, the stream transmission device 10 and the stream reception device 20 may include the following devices. That is, an input device such as a keyboard and a touch panel, an output device such as a display, a communication control device such as a communication interface with other devices, and a storage device as a work area or a data storage location (all not shown) .

The stream transmission unit 1, the probe transmission unit 2, the stream reception unit 3, and the timing estimation unit 4 illustrated in FIG. 1 can be regarded as programs expressed in units of functional blocks. These programs are stored in a CPU (Central Processing Unit) of a computer (not shown), a ROM (Read Only Memory) (not shown), a RAM (Random Access Memory) (not shown), and the like. These functions are executed by a CPU (not shown) appropriately processing these programs. Each unit described above may be configured by dedicated hardware such as an electronic circuit.
(Operation of communication system)
Next, the operation of the communication system 100 according to the first embodiment of the present invention will be described.

  The operations of the stream transmission unit 1 and the stream reception unit 3 will be described with reference to the sequence diagram shown in FIG. In the figure, the time at which the stream transmission unit 1 completes the stream transmission preparation is set to 0. The stream transmission unit transmits the first packet constituting the video stream to the stream reception unit 3 at time b (hereinafter referred to as “initial transmission time b”). At this time, the stream transmitting unit 1 may transmit a plurality of packets. When a plurality of packets are transmitted, they may be transmitted without leaving a packet interval or may be transmitted with an interval.

  When transmission of a packet to be transmitted is completed between the first transmission time b and a predetermined time, the stream transmission unit 1 stops transmission for a while. The time until the stream transmission unit 1 starts transmitting a packet storing data constituting a video frame and starts transmitting a packet storing data constituting the next video frame is referred to as “time interval a”. Assume. In this case, the stream transmission unit 1 transmits the packet of the next video frame at time (a + b) obtained by adding the time interval a to the initial transmission time b. Next, the packet is transmitted again at time (2a + b), and the transmission of the packet is stopped for a while. As described above, the stream transmission unit 1 starts sending packets at time (ai + b), but then temporarily stops sending packets. Note that i is an integer of 0 or more. In other words, there is a certain cycle in packet transmission of the stream transmission unit 1.

  Next, the operations of the probe transmitter 2 and the timing estimator 4 will be described with reference to the flowchart shown in FIG.

  In step S <b> 101, the probe transmission unit 2 transmits a plurality of probe packets toward the timing estimation unit 4. The probe packet transmission interval may be, for example, a method of transmitting at a constant interval, but is not limited thereto.

  In step S102, the timing estimation unit 4 receives the probe packet transmitted by the probe transmission unit 2.

  In step S103, the timing estimation unit 4 calculates a delay time based on the reception time of each probe packet and the transmission time included in each probe packet. Further, the timing estimation unit 4 estimates the timing at which the stream transmission unit 1 transmits a stream, that is, the above-described streaming transmission time interval a and initial transmission time b from the delay time.

  In step S104, the timing estimation unit 4 transmits the estimated timing (time interval a, initial transmission time b) to the probe transmission unit 2.

  In step S105, the probe transmission unit 2 receives the estimated timing transmitted by the timing estimation unit 4. Thereby, the operation | movement in the probe transmission part 2 and the timing estimation part 4 is complete | finished.

  Next, the delay time between the video packet transmitted from the stream transmission unit 1 and the probe packet transmitted from the probe transmission unit 2 described in step S103 will be described. The delay state between the video packet and the probe packet is shown in the graph of FIG. In the figure, a solid line arrow represents a video packet, and a broken line arrow represents a probe packet. p1 to p7 are probe packet identifiers. In addition, the solid line shown in the direction extending downward in the figure represents time (t).

  When the WAN link speed between the relay apparatuses 5a and 5b is lower than that of the LAN, first, video packets and probe packets are buffered as queues in a temporary storage unit (not shown) provided in the relay apparatus 5a. Thereafter, when the transmission of the previous data is completed in the network (WAN) between the relay apparatuses 5a and 5b, the next data is transmitted to the WAN in the order of arrival at the relay apparatus 5a. Therefore, if the speed at which the video packet arrives at the relay device 5a is larger than the WAN link speed, the delay increases in both the video packet and the probe packet. For example, in FIG. 4, the timing at which the probe packet p2 arrives at the relay device 5b from the relay device 5a is delayed due to the transmission of the video packet. In the probe packet p3, the timing at which the relay device 5a arrives at the relay device 5b is delayed due to the transmission of more video packets.

  Therefore, the timing estimation unit 4 estimates the transmission timing of the video packet from the delay of the probe packet. A graph showing the relationship between the transmission time of each probe packet and the delay time is shown in FIG. In the graph of the figure, the horizontal axis represents time (t), and the vertical axis represents delay time. P1 to p7 shown on the horizontal axis represent probe packet identifiers shown in FIG. In addition, rectangular regions q1 and q2 shown along the time axis shown on the horizontal axis represent the time (period) during which the video packet is transmitted. According to the graph shown in FIG. 5, it can be seen that the delay time of the probe packet increases when the transmission of the video packet is started and decreases when the transmission of the video packet is stopped. From this, the timing estimation unit 4 detects the timing at which the delay rises, and determines that timing as an estimated value of the transmission start time of the video packet (see the initial transmission time b shown in FIG. 2). In the graph of FIG. 5, the transmission of the video packet is started at a time between p1 and p2, that is, there is an initial transmission time b.

  In addition, between the relay devices 5a and 5b, as shown in FIGS. 2 and 4, video packets are sent at a constant cycle at a time interval a (1 / fps) after the initial transmission time b. For this reason, it can be predicted that the increase in the delay time of the probe packet described above periodically occurs with the time interval a of the video packet.

  Specifically, the time interval a is estimated by obtaining a value that maximizes autocorrelation with respect to time-series data of delay time. For example, when the time interval a for transmitting a video packet is 100 milliseconds (10 fps), if the probe packet transmission interval is 1 millisecond, a rise in delay occurs every 100 probe packets. That is, the delay times of p1, p2, p3,... In FIG. 5 and the delay times of p101, p102, p103 (not shown),. The autocorrelation function is a function that represents the similarity of graph shapes when time series data is shifted point by point. Therefore, in the above example, the autocorrelation is maximized when the point is shifted by 100 points. Therefore, the point at which the autocorrelation is maximized is set as the estimated value of the time interval a. However, since it is conceivable that the autocorrelation is maximized at a time interval that is a multiple of 100 due to an error or the like, it is possible to make an erroneous determination.

  In the case of more accurately estimating the time when transmission (transmission) of the video packet is started between the probe packets p1 and p2 shown in FIG. 5, the timing estimation unit 4 1) shortens the probe packet transmission interval. Or 2) a method of estimating from the slope of increase (or decrease) in the delay time. That is, in the method 1), after specifying that transmission is started between the probe packets p1 and p2, the probe packet transmission interval between them is shortened. In the method 2), a linear equation connecting p2 and p3 is obtained, and the time when the delay becomes the same value as p1 in this equation is estimated as the transmission time of the video packet.

  As described above, in the first embodiment of the present invention, even when a large amount of data is periodically transmitted, the timing estimation unit 4 recognizes a change in the amount of background traffic, The transmission timing is estimated using the delay time change. Thereby, the transmission timing of the stream can be estimated with high accuracy.

  In the present embodiment, a communication system that uses video packets as data packets has been described as an example. However, if the application regularly transmits packets, the data packet used by the communication system is not limited to a video packet. For example, the present invention can be applied to a system that transmits observation data from a sensor to a server at regular intervals.

  In this embodiment, a method for continuously transmitting probe packets at a fixed interval has been described. However, if the time at which the delay time of the probe packet rises can be identified, it is possible to estimate the transmission timing of the stream without continuing to transmit at fixed intervals. It is. In the second embodiment, a technique for estimating the transmission timing of a stream using the time when the delay time of the probe packet rises will be described.

<Second Embodiment>
(Communications system)
A communication system 200 according to the second embodiment of the present invention will be described. As shown in FIG. 6, the communication system 200 according to the second embodiment includes a stream transmission device 10, a stream reception device 20a, and relay devices 5a and 5b. The stream reception device 20 a includes a stream reception unit 3 and a timing estimation unit 14. The timing estimation unit 14 estimates the transmission timing of the video packet using the probe packet sequence for estimating the available bandwidth. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  A graph of a general probe packet sequence used for the available bandwidth estimation is shown in FIG. In the figure, the horizontal axis indicates the time when the probe packet is transmitted, and the vertical axis indicates the size of the probe packet. In the figure, s1 to sn represent probe packet identifiers. Probe packet s1 to sn are transmitted with the probe packet transmission interval kept constant and the size gradually increased (this means that the bit rate of the probe packet gradually increases in time series). When the bit rate exceeds the usable bandwidth of the network, the probe packet is temporarily stored in the queue (storage area: not shown) of the relay device 5a, so that the packet delay time gradually increases. The timing estimation unit 14 uses this property to estimate the available bandwidth based on a probe packet having a size at which the delay time has started to increase. The probe packet size may be determined depending on the queue size. Further, the size of each probe packet and the transmission interval may be set so that detection is possible at the time of transmission of the video packet in consideration of the size of the video packet. For example, when the size of the video packet whose transmission timing is to be estimated is small, the size of the probe packet may be set so that the total size of the probe packet and the video packet exceeds the size of the queue.

  When there is no video traffic, a linear graph showing the relationship between the size (horizontal axis) and the delay time (vertical axis) of the probe packets s1 to sn shown in FIG. 7 is theoretically directly proportional (not shown). However, when measured, the relationship between the size of the probe packets s1 to sn and the delay time rises gradually with a gentle slope for a while from the start of probe packet transmission, but suddenly increases from a certain point in time. Become. This is probably because the probe packet size exceeds the available bandwidth at that time. For example, referring to FIG. 8, the delay gradient increases with the probe packet size sx (x is an arbitrary integer) as a boundary. Therefore, the timing estimation unit 14 sets the value obtained by the following equation (1) as the estimated value of the usable bandwidth (unit: bps (bits per second)). “/” Represents division.

(Sx [bytes] x 8 [bits / bytes]) / (probe packet transmission interval [seconds]) (1)
The timing estimation unit 14 calculates the theoretical value of the delay time for each packet having a probe packet size larger than sx in consideration of the available bandwidth estimation value obtained by Expression (1). For example, the delay time of a packet exceeding the available bandwidth estimation value (stored in the queue) may be added to the delay time. A curve obtained based on the probe packet size (delay time) until reaching the usable bandwidth and the theoretical value of the delay time after reaching the usable bandwidth is called an ideal curve. When packet transmission / reception (background traffic) in the network is constant, the delay of the probe packet is predicted to be along this ideal curve.

  FIG. 9 shows a graph illustrating an example of the relationship between the probe packet size (horizontal axis) and the delay time (vertical axis) when transmission of a video stream is started during probe packet transmission. When transmission of a video stream is started at the time of transmitting a probe packet of size sx, the available bandwidth decreases due to the influence of video traffic. Thereby, the slope of the delay time of the probe packet becomes larger than the ideal curve. Therefore, the timing estimation unit 14 transmits a probe packet having a size sx at the first time point (a place deviating from the ideal curve) when the slope of the delay time of the probe packet is significantly larger than the ideal curve, for example, in FIG. The time is estimated as the time when transmission of the video stream is started. The time at which the probe packet is transmitted may be any on the ideal curve, and when the video stream is transmitted (in general, the video stream requires a large amount of packet transmission), the video is transmitted. Similarly, the value indicating the probe packet size transmitted immediately after the stream transmission time (the circle on the ideal curve shown in FIG. 9) deviates from the ideal curve. By observing this divergence state, the transmission time of the video stream is estimated.

  In the second embodiment of the present invention, in addition to the effect of the first embodiment, even when a delay occurs due to network traffic, an ideal curve of the delay time is generated, and a deviation state from the ideal curve , And the transmission timing of the video stream can be estimated. This eliminates the need to continue transmitting timing estimation packets used in the first embodiment. As a result, the amount of data flowing through the network can be reduced.

<Third Embodiment>
(Stream receiver)
A stream receiving device 20b according to the third embodiment of the present invention will be described. As shown in FIG. 10, the stream receiving device 20b according to the third embodiment receives a probe packet in a network that transmits and receives data packets and probe packets, calculates a delay time of the probe packets, and calculates The transmission time of the data packet is estimated based on the delay time. In addition, the direction of the arrow in FIG. 10 shows an example, and does not limit the direction of the signal between blocks.

  According to the third embodiment of the present invention, even when a large amount of data is periodically transmitted, the stream transmission timing can be estimated by grasping the change in the background traffic amount.

  In each embodiment of the present invention, each component of each device (system) represents a functional unit block. Part or all of each component of each device (system) is realized by an arbitrary combination of an information processing device 500 and a program as shown in FIG. 11, for example. The information processing apparatus 500 includes the following configuration as an example.

CPU (Central Processing Unit) 501
ROM (Read Only Memory) 502
-RAM (Random Access Memory) 503
A program 504 loaded into the RAM 503
A storage device 505 for storing the program 504
A drive device 507 for reading / writing the recording medium 506
Communication interface 508 connected to the network 509
An input / output interface 510 for inputting / outputting data
-Bus 511 connecting each component
Each component of each device in each embodiment is realized by the CPU 501 acquiring and executing a program 504 that realizes these functions. The program 504 that realizes the function of each component of each device is stored in advance in the storage device 505 or the RAM 503, for example, and is read by the CPU 501 as necessary. Note that the program 504 may be supplied to the CPU 501 via the network 509 or may be stored in the recording medium 506 in advance, and the drive device 507 may read the program and supply it to the CPU 501.

  There are various modifications to the method of realizing each device. For example, each device may be realized by an arbitrary combination of the information processing device 500 and a program that are separately provided for each component. A plurality of constituent elements included in each device may be realized by an arbitrary combination of one information processing device 500 and a program.

  In addition, some or all of the components of each device are realized by other general-purpose or dedicated circuits, processors, and the like, or combinations thereof. These may be configured by a single chip or may be configured by a plurality of chips connected via a bus.

  Part or all of each component of each device may be realized by a combination of the above-described circuit and the like and a program.

  When some or all of the constituent elements of each device are realized by a plurality of information processing devices and circuits, the plurality of information processing devices and circuits may be centrally arranged or distributedly arranged. Also good. For example, the information processing apparatus, the circuit, and the like may be realized as a form in which each of them is connected via a network, such as a client and server system and a cloud computing system.

  The present invention has been described above using the above-described embodiment as an exemplary example. However, the present invention is not limited to the above-described embodiment. That is, the present invention can apply various modes that can be understood by those skilled in the art within the scope of the present invention.

  This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2014-259007 for which it applied on December 22, 2014, and takes in those the indications of all here.

DESCRIPTION OF SYMBOLS 1 Stream transmission part 2 Probe transmission part 3 Stream reception part 4, 14 Timing estimation part 5a Relay apparatus 5b Relay apparatus 10 Stream transmission apparatus 20, 20a, 20b Stream reception apparatus 100 Communication system 200 Communication system

Claims (10)

In the network that transmits the data packet and the probe packet, the probe packet is received, the delay time of the probe packet is calculated, and the transmission time of the stream of the data packet is estimated based on the calculated delay time ,
Stream receiver. The probe packet includes information about the time at which it was transmitted,
The stream receiver according to claim 1. The stream receiving apparatus according to claim 1, wherein a time when the delay time of the probe packet is increased is estimated as a transmission time of the data packet stream. The transmission of the stream is based on the increase in the delay time of the second probe packet transmitted after the first probe packet with respect to the delay time of the first probe packet transmitted first among the probe packets. The stream receiving apparatus according to claim 1, wherein the interval is estimated. A stream receiving device according to any one of claims 1 to 4;
A stream transmission device for transmitting the data packet and the probe packet;
The stream receiving device and the stream transmitting device are communicably connected via the network.
Communications system. The stream transmission device includes:
Stream transmitting means for transmitting the data packet;
The communication system according to claim 5, further comprising probe transmission means for transmitting the probe packet. The communication system according to claim 5, wherein the probe transmission unit transmits the probe packet at regular intervals. The probe transmitting means increases the size of the second probe packet to be transmitted after the first probe packet as compared with the size of the first probe packet to be transmitted first, and transmits the probe packet. A communication system according to any one of the above. In the network that transmits the data packet and the probe packet, the probe packet is received;
Calculating a delay time of the probe packet;
Based on the calculated delay time, estimate a transmission time of the data packet;
Estimation method. A method of receiving the probe packet in a network for transmitting a data packet and a probe packet, calculating a delay time of the probe packet, and estimating a transmission time of the data packet based on the calculated delay time;
A recording medium for storing an estimation program for causing a computer to execute.

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