WO2006013618A1

WO2006013618A1 - Transmission control device

Info

Publication number: WO2006013618A1
Application number: PCT/JP2004/011063
Authority: WO
Inventors: Junichi Yokosato; Fuminobu Ogawa; Yuka Fujita
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 2004-08-02
Filing date: 2004-08-02
Publication date: 2006-02-09
Also published as: JPWO2006013618A1

Abstract

Transmission state information in a network between a server device and a client device is acquired and stored in transmission state information storage means. When server transmission control means detects deterioration of the transmission state from the transmission state information, an instruction to lower the transmission band is transmitted to all the server devices which are performing transmission. Moreover, when a new server device starts transmission, the transmission band is re-allocated to each server and a transmission band modification instruction is transmitted to the server device which has modified the band.

Description

Specification

Transmission control device

Technical field

The present invention relates to a transmission control apparatus that performs network congestion control when transmitting digital data such as moving image data and audio data between a plurality of server apparatuses and a plurality of client apparatuses on a network. It is about. Background art

[0002] In recent years, transmission systems for transmitting multimedia data such as moving image data and audio data via a network such as the Internet have become very popular. In this situation, since multiple users share the transmission band on the network, a congestion problem has occurred. Therefore, congestion avoidance and control of calming when congestion occurs have been required. As a congestion control method for transmitting real-time data such as moving image data, high-quality moving image data is transmitted when the network is not congested, while the encoding rate is increased. It is known that by reducing the image quality, the quality of video data will be reduced to some extent, but it will be transmitted to avoid congestion.

In this congestion control method, the network congestion state is determined on the data transmission device side such as moving image data. For this purpose, for example, the protocol control standardized as RFC3550, RTP (Rea Time Transport Protocol). ) And RTCP (RTP Control Protocol) are used. RTCP specifies a protocol for transmitting and receiving information necessary to control transmission and reception of RTP packets for transmitting real-time data such as video data. When transmitting real-time data according to RTP, the sender report packet indicating the transmission status is transmitted from the data transmitter to the receiver, and the receiver report packet indicating the reception status of the RTP packet is transmitted from the receiver. To do. Here, the sender report packet is information including the time when the RTP packet was transmitted, the number of transmitted RTP packets, the number of bytes of the RTP packet, and the like. On the other hand, the receiver report packet includes the packet discard rate of the received RTP packet, the number of discarded packets, and the maximum sequence number of the received RTP packet. Number, arrival interval jitter, time at which the sender report packet was last received, and time elapsed since that time.

[0004] The data transmission apparatus determines the congestion state of the network based on the receiver report packet transmitted periodically. In this determination, the packet discard rate of the RTP packet is recognized, and if there is packet loss, it is recognized that the network is congested and there is a high probability of data being discarded at the relay node. Conversely, when the packet loss rate is zero, it is recognized that there is no congestion in the network.

[0005] However, data loss that occurs in a network may not be due to network congestion. In other words, in addition to network congestion, data loss includes simple bit errors during transmission or temporary loss due to traffic bursts. Therefore, if there is a case where the data transmission device responds to a temporary data loss due to other than network congestion and the encoding rate is lowered, the real-time data such as moving images and voices will also improve the communication quality. It will be reduced unnecessarily.

[0006] In consideration of the above-mentioned problem, when transmitting real-time data, a technique for preventing communication from being sensitive to data loss and stabilizing communication quality is disclosed in, for example, Japanese Patent Laid-Open No. 2001-320440. No. 1 (Patent Document 1). Here, when the data transmission device receives the data loss rate (corresponding to the packet discard rate) sent from the data reception device, the data loss rate is set to the first threshold value and the second threshold value set in advance. Compared with the threshold value, the following control is performed according to the result. In other words, if the data loss rate is lower than the first threshold and the second threshold, the transmission rate is increased. Also, if the data loss rate is higher than the first threshold and lower than the second threshold, the transmission rate is not changed. Furthermore, when the data loss rate is higher than the first threshold and the second threshold, the transmission rate is reduced.

[0007] With the conventional techniques as described above, assuming that a real-time data is transmitted in pairs between the data transmission device and the data reception device, data transmission is performed based on the data loss rate between the two. The transmission rate is controlled on the device side. In contrast, video transmission systems that transmit real-time data from a plurality of data transmission devices to a plurality of data reception devices via a network have appeared. In that case, send and receive in pairs as above In the method of controlling the transmission rate only between the data transmitting apparatus and the data receiving apparatus that performs the transmission, it is difficult to control the transmission of the entire system in an integrated manner and efficiently use the network bandwidth.

[0008] The present invention has been made to solve the above-described problems. In the case where digital data such as multimedia data is transmitted between a plurality of server devices connected to a network and a plurality of client devices. Another object of the present invention is to obtain a transmission control device that can monitor the transmission status on the network and control the transmission band of multiple server devices in an integrated manner.

Disclosure of the invention

[0009] A transmission control device according to the present invention is a transmission control device connected to a network for transmitting transmission data such as moving image data and audio data from a plurality of server devices to a plurality of client devices. Transmission status information storage means for acquiring transmission status information in the network between the device and client device at the start of transmission, during transmission and at the end of transmission and storing it by registration or update, and monitoring the stored transmission status information When a deterioration in transmission status is detected from the transmission status information, a command to lower the transmission bandwidth is sent to all server devices that are transmitting, and when a server device that has newly started transmission appears. Includes server transmission control means for reallocating the transmission bandwidth of each server device and transmitting a transmission bandwidth change command to the server device whose bandwidth has been changed. Those were.

[0010] With this, the transmission status of a complex transmission system such as multimedia data formed on the network is monitored, and the transmission band of a plurality of server devices is integrated to control the transmission system. It has the effect of efficiently using the limited network bandwidth.

Brief Description of Drawings

FIG. 1 is a block diagram showing a configuration of a transmission system to which a transmission control device according to each embodiment of the present invention is applied.

FIG. 2 is a block diagram showing a configuration of a transmission control apparatus according to Embodiment 1 of the present invention.

FIG. 3 is an explanatory diagram showing a data configuration of transmission status information according to the first embodiment of the present invention. The

FIG. 4 is a block diagram showing a configuration of a transmission control apparatus according to Embodiment 2 of the present invention.

FIG. 5 is a block diagram showing a configuration of a transmission control apparatus according to Embodiment 3 and Embodiment 4 of the present invention.

FIG. 6 is a block diagram showing a configuration of a transmission control apparatus according to Embodiment 5 of the present invention.

FIG. 7 is a block diagram showing a configuration of a transmission control apparatus according to Embodiment 6 of the present invention.

FIG. 8 is a block diagram showing a configuration of a transmission control apparatus according to Embodiment 7 of the present invention.

FIG. 9 is a block diagram showing a configuration of a transmission control apparatus according to Embodiment 8 of the present invention.

FIG. 10 is a block diagram showing a configuration of a transmission control apparatus according to Embodiment 9 of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, in order to describe the present invention in more detail, the best mode for carrying out the invention will be described with reference to the accompanying drawings.

Embodiment 1.

FIG. 1 is a block diagram showing a configuration of a transmission system to which a transmission control device according to each embodiment of the present invention is applied. A plurality of server devices are provided with moving image data acquired from a video image for a plurality of client devices. A transmission system for stream transmission is shown as an example.

In the figure, a plurality of server apparatuses SRV1 SRVn are connected to a network 107. Video cameras CAM1-CAMn for capturing moving images are connected to server devices SRV1 SRVn, respectively. In this example, a single video camera may be connected to a single server device. A plurality of cameras may be connected. A plurality of client devices CLT1 and CLTm and the transmission control device 111 of the present invention are connected to the network 107.

[0013] As an example of the operation mode of the transmission system assumed here, at least one client device (for example, CTL1) has one or more server devices (for example, SRV1-SRVi, where i≤n). ) From the same time zone, multiple client devices (for example, CLT1 one CLTk, where k≤m) are moving images from at least one server device (eg SRV1). If you want to use the data at the same time, or The combined maximum case, that is, the case where all the client devices CLT1 and CLTm use moving image data from all server devices SRV1-SRVn in the same time zone, is considered. The transmission control device 111 of the present invention performs the control operation described below according to these operating modes.

[0014] Assume that a client device (for example, CLT1) transmits a transmission request to one or more of server devices SRV1 SRVn. This transmission request is implemented, for example, using RTSP (Real Time Streaming Protocol) defined in RFC2326 of IET F. The server device (for example, SRV2) that receives the transmission request from the client device CLT1 digitizes and encodes the video captured by the corresponding video camera CAM2 to generate moving image data. The RTP specified in IETF RFC3550 (Rea 卜 Time Transport Protocol) is used to transmit to the requested client device CLTl. During transmission of moving image data by RTP, RTCP (RTP Control Protocol) SR (Sender R mark ort: Sender report packet) specified in IETF RFC3550 is sent from server SRV2 to client CLT1. The client device CLT1 transmits an RTCP RR (Receiver R mark or hereafter: receiver report packet) to the server SRV2. Each server device can transmit video data to a plurality of client devices, and transmission of moving image data is performed by multicast. If the transmission is multicast, RTCP SR and RR are also sent by multicast.

FIG. 2 is a block diagram showing a configuration of the transmission control apparatus according to the first embodiment. The transmission control device 111 includes a transmission start information receiving unit 201, a transmission status information receiving unit 202, a server transmission control unit 203, and a transmission status information storage unit 204.

When each server device (for example, SRV1 SRVi) receives a transmission request from a client device (for example, CT L1), it starts multicast transmission to this client device CTL1. In this case, each server SRV1 SRVi has the server ID, initial transmission destination client ID, RTP and RT CP multicast address used for multicast transmission, each port number, its media type, and camera ID as TCP (Transmission Control Protocol) is notified to the transmission control device 111 by communication. [0016] In the transmission control apparatus 111, when the transmission start information receiving unit 201 receives the multicast address and port number of RTP and RTCP used for multicast transmission, the media type, and the camera ID, the information is transmitted to the transmission status information receiving unit. Notify 202. The transmission status information receiving unit 202 starts receiving the receiver report packet related to the notified multicast transmission, and registers the received information in the transmission status information storage unit 204. The receiver report packet includes the packet discard rate (the packet discard rate from when the client device sent the previous receiver report packet until it sent the current receiver report packet), the total number of discarded packets, and the arrival interval jitter. Etc. are included.

FIG. 3 shows the data configuration of transmission status information stored in transmission status information storage section 204.

Information on the server device and the client device connected to it is arranged in pairs in the row (horizontal) direction. In the (IK vertical) direction, each set of data, that is, server device ID 301, client device ID 302, multicast address 303, target RTP port number 304, packet discard rate (the client device sends the previous recipient report packet) Packet discard rate from when the current receiver report packet is transmitted) 305, total packet discard number 306, arrival interval jitter 307, media type 308, and camera ID 309 are arranged in order

[0018] When the server apparatus (for example, SRV1) receives a transmission request (RTSP PLAY command) for a new client apparatus (for example, CLT2) force data transmission, the server apparatus (for example, SRV1) Send a new client reception start notification. When the transmission start information receiving unit 201 receives this new client reception start notification, the transmission start information receiving unit 201 transfers the new client reception start notification to the transmission status information receiving unit 202. The new client reception start notification includes the server device ID of the server device SRV1, the camera ID, the RTP multicast address and port number that have started reception, the media type, and the client device ID of the client device CLT2 that is to be received. The transmission status information receiving unit 202 adds the received new client reception start notification to the transmission status information storage unit 204 as transmission status information, and then updates the transmission status information each time a receiver report is received.

[0019] When the server SRV1 receives a client device (for example, CLT1) power transmission end request (RTSP TEARDOWN command), the transmission controller 111 starts transmission. A client reception end notification is transmitted to the start information receiving unit 201. This client reception end notification includes the reception RTP multicast address and port number, the media type, and the client device ID for which reception ends. The transmission start information receiving unit 201 transfers this client reception end notification to the transmission status information receiving unit 202. The transmission status information receiving unit 202 deletes the corresponding data stored from the transmission status information storage unit 204 based on the received client reception end notification.

The server transmission control unit 203 periodically refers to the transmission status information in the transmission status information storage unit 204 and monitors the network status. In the first embodiment, the method for judging the transmission status of the network from the transmission status information is not particularly specified. For example, when the bucket discard rate 305 increases from a predetermined value, the increase is caused by a plurality of monitoring cycles. The method described in the above-mentioned Patent Document 1 or the like can be considered. In the description of the present invention, the state where the transmission state is deteriorated by such a method will be expressed as “deterioration of the transmission state” below. The server transmission control unit 203 sends a command to lower the transmission band to all the server devices that are transmitting moving image data when the transmission state deterioration is detected from the transmission state information managed by the transmission state information. To do. In addition, when a server device that has newly started transmission of transmission data appears, the transmission bandwidth of each server device, including those that are currently being transmitted, is reassigned to the server device whose bandwidth has been changed. Sends a transmission band change command.

This operation can reduce the packet discard rate in the transmission system because it reduces the overall network transmission.

[0021] As described above, according to the first embodiment, transmission status information in the network between the server device and the client device is acquired at the start of transmission, during transmission, and at the end of transmission, and is transmitted. (Transmission status information storage means) When stored in 204 and the server transmission control section (Server transmission control means) 203 monitors the stored transmission status information and detects a deterioration in transmission status from the transmission status information Sends a command to lower the transmission bandwidth to all server devices that are transmitting, and if a server device that has newly started transmission appears, the transmission bandwidth of each server device is reassigned to the bandwidth. A transmission band change command is sent to the server device that has changed. Therefore, the entire net The amount of work transmission can be reduced, and the packet discard rate in the transmission system can be reduced. In other words, by monitoring the transmission status of complex transmission systems such as multimedia data formed on the network and controlling the transmission bandwidth of multiple server devices in an integrated manner, the limited network bandwidth of the transmission system can be reduced. The effect of enabling efficient use is obtained.

[0022] Embodiment 2.

FIG. 4 is a block diagram showing the configuration of the transmission control apparatus according to Embodiment 2 of the present invention. In the figure, parts corresponding to those in FIG. The transmission control device 111 according to the second embodiment is provided with a server transmission priority control unit 402 instead of the server transmission control unit 203 in FIG. 2, and a server priority information storage unit 401 is newly provided. Different from 1. Here, the server transmission priority control unit 402 is the same as the server transmission control unit 203 in that the transmission status information is monitored, but otherwise performs processing described later with reference to the server priority information storage unit 401.

[0023] The server priority information storage unit 401 stores in advance server priority information including a server device ID, a camera ID connected to the server device, a multicast address, an RTP port number, and a priority assigned to the server device. Stored. The priority used here is, for example, determined in advance in five levels, and the server device connected to the network is assigned to one of the five levels of priority. Therefore, different server devices may share the same priority.

[0024] The server transmission priority control unit 402 refers to the transmission status information storage unit 204, and controls the transmission band when the deterioration of the transmission status is detected from the transmission status information. At that time, the server transmission priority control unit 402 refers to the server priority information storage unit 401, and stores the video image data from the video camera of the server device in order from the lowest priority registered in the server priority information. A command to lower the transmission band is sent to the corresponding server device. The server device that has received the command operates to reduce the transmission band of the moving image data in accordance with the command. As a result, even if the transmission amount in the network 107 is reduced, high-priority moving image data can be continuously transmitted without reducing the bandwidth. As described above, according to the second embodiment, the server priority information including the priority given in advance to each server device is transmitted to the server priority information storage unit (server priority information storage unit) 401. When the server transmission priority control unit (server transmission priority control means) 402 detects deterioration of the transmission status from the transmission status information, the server priority information is referred to in order of decreasing priority. An instruction to lower the transmission bandwidth of the transmission data of the server device is sent to the corresponding server device. Therefore, for example, in a video surveillance system, video data from an important video camera is transmitted without dropping the bandwidth, while only video data from a video camera with low importance is transmitted. It is possible to reduce the transmission volume of the entire system by lowering the transmission bandwidth of the system. In other words, since the server priority information is used to select the target data for multiple transmission data transmissions that are transmitted by multiple server devices, the transmission band can be controlled in an integrated manner. .

Embodiment 3.

FIG. 5 is a block diagram showing the configuration of the transmission control apparatus according to Embodiment 3 of the present invention. In the figure, parts corresponding to those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted in principle. The transmission control apparatus 111 of the third embodiment is different from the second embodiment in that a priority change receiving unit 501 is provided in addition to the configuration of FIG. Here, the server transmission priority control unit 402 performs slightly different processing from that in the second embodiment as will be described later.

When the priority of transmission data transmitted by a server device itself is changed, the server device transmits a priority change notification to the transmission control device 111. The priority change notification includes the server device ID and camera ID, and the priority after the change. In the transmission control device 111, when the priority change receiving unit 501 receives the priority change notification, the priority of the server priority information corresponding to the transmission data of the corresponding server device in the server priority information storage unit 401 is changed. Change to priority based on notification.

Next, after referring to the transmission status information, the server transmission priority control unit 402 refers to the server priority information storage unit 401. This reference operation is performed not only when the deterioration of the transmission status is detected but also when it is not detected. At this time, if a new priority after change is detected in the server priority information, the moving image from the server device with the priority after the change is detected. A command to change the data transmission band based on the priority after the change is transmitted to the corresponding server device. Therefore, transmission band control can be performed corresponding to dynamic server priority information. Further, when the priority change notification is received from the server device in this way, the server transmission priority control unit 402 reallocates the transmission bandwidth of each server device based on the updated server priority information, and A transmission band change command is issued to the server device that needs to be changed.

[0028] As described above, according to the third embodiment, the server priority information corresponding to the transmission data of the corresponding server device according to the priority change notification including the changed priority received from any server device is obtained. Change the server transmission priority control unit (server transmission priority control means) 4 02 and refer to the transmission status information, then refer to the server priority information and detect the changed priority. A command to change the transmission band of transmission data from the device based on the priority after the change is transmitted to the corresponding server device. Therefore, for example, in the case of a video monitoring system, priority is given to the transmission band of the video data corresponding to the alarm information by changing the priority of the video data from the video camera corresponding to the sensor that generated the alarm information to a higher setting. It is possible to change and transmit it. In this way, it is possible to dynamically reallocate the transmission band even if the server priority information changes during system operation. In other words, transmission data is selected to be transmitted by multiple server devices in response to changes in the priority information of the server device, and transmission data for performing transmission power transmission band control is selected. The effect that can be controlled is obtained.

[0029] Embodiment 4.

In FIG. 5, a priority change notification may be sent directly from the client device to the priority change receiving unit 501 from the server device. In this case, the server priority information can be changed by the same management method and processing as in the third embodiment. The contents of the priority notification in this case are also the same.

In this case, in order to deal with an emergency situation in the video surveillance system, the supervisor who is viewing the video directly reports the priority change from the client device in charge to the transmission control device 111. And set the priority of the target stream to a high priority It enables browsing without changing the rate of image data.

[0030] Embodiment 5.

FIG. 6 is a block diagram showing a configuration of a transmission control apparatus according to Embodiment 5 of the present invention. In the figure, parts corresponding to those in FIG. The transmission control apparatus 111 according to the fifth embodiment includes a server transmission priority control unit 4021 instead of the server transmission control unit 203 in FIG. 2, and newly includes a data transmission amount information storage unit 601 and a data transmission amount information reception unit. The difference from Embodiment 1 is that 602 is provided. Here, the server transmission priority control unit 4021 monitors the transmission status information with the same force S as the server transmission control unit 203, and other processing described later with reference to the data transmission amount information storage unit 601. I do

[0031] When receiving the RTCP multicast address and port number notification from the transmission start information receiving unit 201, the data transmission amount information receiving unit 602 starts receiving the sender report. Here, the sender report stores correspondence information between RTP timestamps and NTP timestamps, the total number of transmitted packets, and the total number of transmitted payload octets. When the data transmission amount information receiving unit 602 receives the sender report sequentially, the total number of transmitted payload octets (sender's octet count) included in the sender report and the total number of transmission reports of J sender reports are calculated. The average bit rate (data transmission amount information) of the payload transmitted by each server device is calculated by dividing the difference by the time stamp difference between the current and previous sender reports. The calculated average bit rate is stored in the data transmission amount information storage unit 601 together with the server apparatus ID, the RTP multi-cache address, and the reception port.

The data to be stored in the data transmission amount information storage unit 601 can be transmission data using an original protocol other than using the RTCP sender report. For example, for each piece of transmission data sent by each server device at a fixed time, information related to the transmission rate of the transmission data including the average bit rate, multicast address, and port number is transmitted to the transmission control device 111. The same effect can be obtained by transmitting to the other side.

[0032] The server transmission priority control unit 4021 refers to the data transmission amount information storage unit 601 when it detects a deterioration in the transmission status from the transmission status information. The ratio of the amount of transmitted data is calculated based on the average bit rate of the load. Next, an instruction to lower the transmission band is transmitted to the corresponding server device only for moving image data when the calculated ratio is equal to or greater than a predetermined threshold. In addition, when the ratio of the amount of transmission data changes by a certain amount or more, the transmission band allocation to each server device is calculated again, and a transmission band change command is sent to the server device that has changed. As a result, it is possible to reduce the bandwidth of only the transmission data from the server device that uses a large bandwidth.

[0033] As described above, according to the fifth embodiment, the data transmission amount information receiving unit (data transmission amount information receiving means) 602 sequentially receives the power of each server device and the transmission rate of each transmission data. Data transmission volume information is calculated based on the related information, and the calculated data transmission volume information is stored in the data transmission volume information storage unit (data transmission volume information storage unit) 601, and the server transmission priority control unit (server (Transmission priority control means) When the transmission status information capability or the deterioration of the transmission status is detected by 4021, the transmission rate of each transmission data sent by each server device is referred to by referring to the stored data transmission amount information. Based on the above, the ratio of the amount of transmission data is calculated, and an instruction to lower the transmission band only for transmission data when the calculated ratio is equal to or greater than a predetermined threshold is transmitted to the corresponding server device. In Yes.

[0034] Therefore, since it is possible to reduce the bandwidth of only the transmission data from the server device that uses a large bandwidth, the server device that originally transmits in the low bandwidth does not affect the server device. It is possible to reduce the load on the network. For example, if there are multiple server devices that deliver 6 Mbps MPE G-2 video data and multiple server devices that deliver 128 Kbps MPEG-4 video data, the network load increases and transmission bandwidth is controlled. The network load can be reduced without reducing the bandwidth of 6 Mbps MPEG-2 transmission data and the bandwidth of 128 kbps MPEG-4 transmission data. In other words, by using the occupancy rate of the transmission data amount of each server device over the entire bandwidth of the network, the transmission data for selecting the transmission data medium transmission bandwidth control of the plurality of server devices is selected. As a result, the transmission band can be controlled in an integrated manner.

[0035] Embodiment 6. FIG. 7 is a block diagram showing a configuration of a transmission control apparatus according to Embodiment 6 of the present invention. In the figure, parts corresponding to those in FIG. The transmission control device 111 according to the sixth embodiment includes a server transmission priority control unit 4022 instead of the server transmission control unit 203 in FIG. 2, and a new transmission request frequency history storage unit 701. Different from 1. Here, the server transmission priority control unit 4022 is the same as the server transmission control unit 203 in that the transmission status information is monitored, but additionally performs processing described later with reference to the transmission request frequency history storage unit 701.

A difference from Embodiment 2 is that a transmission request frequency history storage unit 701 is provided instead of the server priority information storage unit 401 of FIG.

The transmission request frequency history storage unit 701 stores each server device ID and transmission request frequency history data for managing the number of transmission requests from the client device to the server device. When a new client device sends a transmission start request to a certain server device, the transmission status information receiving unit 202 sends the server device related to the server device to the transmission request frequency history of the transmission request frequency history storage unit 701. Increase the number of transmission requests corresponding to ID, RTP multicast address, and port number by one. The server transmission priority control unit 4022 refers to the transmission request frequency history storage unit 701 when detecting the deterioration of the transmission status from the transmission status information, and if there is a server device whose transmission request frequency is a predetermined value or less. A command to lower the transmission band is sent only to the server device. As a result, the bandwidth of the moving image data of the server device having a high browsing frequency can be reduced, and the bandwidth of only the moving image data of the server device having a low browsing frequency can be reduced. Note that the server transmission priority control unit 4022 may use the server device that lowers the transmission band with the lowest value (excluding 0) instead of the transmission request frequency that has been kept below the predetermined value. Alternatively, it may be assumed that it is at a predetermined ratio (for example, low frequency, 30./o).

As described above, according to the sixth embodiment, the transmission request frequency regarding the transmission start request transmitted from the client device to each server device is transmitted as the transmission request frequency history for each server device. Stored in the history storage unit (transmission request frequency history storage means) 701, and when the server transmission priority control unit (server transmission priority control means) 4022 detects deterioration of the transmission status from the transmission status information, the transmission request frequency Browse history A command to lower the transmission band is transmitted only to the server device having the lowest transmission request frequency, a predetermined value or less, or a predetermined ratio. Therefore, since the bandwidth of only the transmission data of the server device with low browsing frequency is reduced, the influence on the client device using the transmission data of the server device with high browsing frequency is minimized. .

[0038] For example, in a video surveillance system, a server device that transmits video data of a video camera installed in a place where many accidents have occurred in the past must be accessed from a client device. It is thought that it will increase in number. In such a system, when the network load becomes high, the network bandwidth is reduced by lowering the transmission band of the moving image data transmitted by the server device other than the server transmission regarded as important. It is only necessary to reduce the load. In other words, by using the transmission request frequency issued in the past from each client device to each server device, the target transmission data for transmission band control is selected from the plurality of transmission data transmitted by the plurality of server devices. Therefore, the effect that the transmission band can be controlled in an integrated manner can be obtained.

[0039] Embodiment 7.

FIG. 8 is a block diagram showing a configuration of a transmission control apparatus according to Embodiment 7 of the present invention. In the figure, parts corresponding to those in FIG. The transmission control device 111 according to the seventh embodiment is provided with a server transmission priority control unit 4023 instead of the server transmission control unit 203 in FIG. 2 and a transmission client device number storage unit 801. Different from 1. Here, the server transmission priority control unit 4023 performs processing described later with reference to the transmission client device number storage unit 801 in addition to the same power as the server transmission control unit 203 in that the transmission status information is monitored.

[0040] The transmission client device number storage unit 801 stores a server device ID, a multicast address, an RTP port number, and the number of receiving client devices of the stream. In the transmission status information receiving unit 202, when a new client device participates in data reception regarding moving image data from a certain server device, the number of receiving client devices of the corresponding server device in the transmission client device number storage unit ₈₀₁ is increased by 1. Let Also, the transmission status information receiving unit 202 receives the client reception end notification via the transmission start information receiving unit 201 and receives the transmission status. When the corresponding data is deleted from the information storage unit 204, the corresponding number of transmission client devices is decreased by one. As a result, the number of client apparatuses receiving the moving image data of each server apparatus currently transmitted can be managed using the number of transmission client apparatuses.

[0041] When the server transmission priority control unit 4023 detects the deterioration of the transmission status from the transmission status information, the server transmission priority control unit 4023 refers to the transmission client device count storage unit 801, and the client device whose number of devices is equal to or smaller than a predetermined value (multiple devices) If there is a server device that transmits moving image data, a command to lower the transmission band is sent only to that server device. If the number of client devices received during transmission changes, the transmission bandwidth allocation to each server device is calculated again, and the transmission bandwidth is changed for the server device that has changed. Make a notification. Note that the server transmission priority control unit 4023 may use the lowest value (excluding 0) instead of the number of client devices that have been set as the target of the server device that lowers the transmission bandwidth. Alternatively, it may be a predetermined ratio (for example, 30% from the lowest number of devices).

As described above, according to the seventh embodiment, the number of received client devices related to the client device receiving the transmission data of each currently transmitted server device is transmitted for each server device. Number storage unit (transmission client device number storage means) 801, and when the server transmission priority control unit (server transmission priority control means) 4023 detects the deterioration of the transmission status information power, the receiving client By referring to the number of devices, the command is transmitted to the client device having the lowest number of devices, less than or equal to a predetermined value, or in a predetermined ratio, and a command to lower the transmission band is transmitted only to the server device. RU Therefore, it is possible to perform transmission band control while minimizing the number of client devices affected by lowering the transmission band.

[0043] For example, in a video surveillance system, the video content of a video camera connected to a certain server device shows problematic content, and 10 surveillance staff members are examining good workarounds while watching the video. When the network load is high, the bandwidth of the video data viewed by 10 observers is not reduced, and the bandwidth of the other video data bandwidth is reduced to reduce the network load. Is possible. That is, by using the current number of receiving client devices transmitting each server device, a plurality of servers are used. Since transmission data for performing transmission band control is selected from among a plurality of transmission data transmitted by the buffer device, an effect of controlling the transmission band in an integrated manner can be obtained.

[0044] Embodiment 8.

FIG. 9 is a block diagram showing a configuration of a transmission control apparatus according to Embodiment 8 of the present invention. In the figure, parts corresponding to those in FIG. The transmission control apparatus 111 according to the eighth embodiment includes a server transmission priority control unit 4024 instead of the server transmission control unit 203 in FIG. 2, and a new client priority information storage unit 901. Different from 1. Here, the server transmission priority control unit 4024 is the same as the server transmission control unit 203 in that the transmission status information is monitored, but additionally performs processing described later with reference to the client priority information storage unit 901.

[0045] In the client priority information storage unit 901, client priority information including the client device ID and the priority for each client device is registered and stored in advance. When the server transmission priority control unit 4024 detects the deterioration of the transmission status from the transmission status information, the server transmission priority control unit 4024 extracts the client device ID of the client device currently transmitting from each server device from the transmission status information, and uses that ID. The priority of the corresponding client device is retrieved from the client priority information. Next, when it is detected that there is a client device with the searched priority equal to or higher than a predetermined value, an instruction to lower the transmission bandwidth of the transmission data of the server device not transmitting to the client device is issued. Sent to the server device. If the client device starts receiving data with a high priority during transmission, the transmission bandwidth allocation to each server device is calculated again, and the transmission bandwidth is changed for the server device that has changed. Make a notification. The server transmission priority control unit 4024 transmits the data to a client device having a priority equal to or higher than a predetermined value as the target of the server device for lowering the transmission band. As a condition of the degree, instead of setting it to a predetermined value or more, the condition may be the lowest value (excluding 0), or a predetermined ratio (for example, low priority, 30% from the side). Use it.

As described above, according to the eighth embodiment, the priority of each client device is stored in advance in the client priority information storage unit (client priority information storage unit) 901, and server transmission priority is set. Control section (server transmission priority control means) 4024 When the deterioration of the transmission status is detected, the priority of the client device currently transmitting is searched from the client priority information, and the searched priority is the highest value, a predetermined value or more, or a predetermined ratio. A command to lower the transmission bandwidth of the transmission data of the server device not transmitted to the client device is sent to the corresponding server device. Therefore, transmission band control can be performed without affecting the client device with high priority.

[0047] For example, by registering the client device being viewed by the department manager as the highest priority client device, even if the network is congested, the client device being viewed by the manager is receiving data that is being received. By changing the transmission band of other transmission data that does not affect the data, it becomes possible to reduce the congestion of the system. In other words, by using the priority of the client device being transmitted, the target transmission data for transmission band control is selected from the plurality of transmission data transmitted by the plurality of server devices, and the transmission band is integrated. A controllable effect is obtained.

[0048] Embodiment 9.

FIG. 10 is a block diagram showing the configuration of the transmission control apparatus according to Embodiment 9 of the present invention. In the figure, parts corresponding to those in FIG. 2 are assigned the same reference numerals, and explanations thereof are omitted in principle. The transmission control apparatus 111 according to the ninth embodiment includes a server transmission priority control unit 4025 instead of the server transmission control unit 203 in FIG. 2, and newly includes a transmission media information storage unit 1001 and a media priority information storage unit 1002. This is different from the first embodiment. Here, the server transmission priority control unit 4025 is the same as the server transmission control unit 203 in that it monitors the transmission status information, but also see the transmission media information storage unit 1001 and the media priority information storage unit 1002. Then, the processing described later is performed.

When the transmission start information receiving unit 201 receives the notification of reception start, the transmission start information receiving unit 201 registers and stores transmission media information related to the media type transmitted by each server device in the transmission media information storage unit 1001. This transmission media information includes a server device ID, a manocast address, a port number, and a transmission media type for each server device. In the media priority information storage unit 1002, media priority information including the media type and the media priority is registered and stored in advance. [0050] When the server transmission priority control unit 4025 detects the deterioration of the transmission status from the transmission status information, the server transmission priority control unit 4025 searches the transmission media information storage unit 1001, and determines the media type transmitted by each server device from the transmission media information. To extract. Next, refer to the media priority information for the extracted media types, compare the media priorities, and transfer the media information to the server device that transmits the media information. Sends a command to reduce the transmission data transmission bandwidth. Therefore, high-priority media types can be transmitted preferentially without lowering the transmission band.

[0051] As described above, according to the ninth embodiment, when transmission of a server device starts, transmission media information including the media type of transmission data that the server device transmits to the client device is transmitted to the transmission media information storage unit. (Transmission media information storage means) 1001 and media priority information including the media type and its media priority are stored in advance in the media priority information storage section (media priority information storage means) 1002, When the server transmission priority control unit (server transmission priority control means) 4025 detects that the transmission status information power has deteriorated, the media type transmitted by each server device is extracted from the transmission media information and extracted. Compare the media priority with the other media information in the media priority information for the selected media type, and select the media with the lowest media priority. If there is carrier information, it sends a command to lower the transmission bandwidth of the transmission data to the server device that transmits the media information with the lower media priority.

[0052] Therefore, transmission with high priority and media type can be preferentially transmitted, and transmission bandwidth is not affected for client devices using transmission data with high priority and media type. Control can be performed. For example, in a transmission system in which moving image data and audio data are synchronized and transmitted between a plurality of server devices and a plurality of client devices, the network is congested by registering audio as a medium with high priority. Even in the case of a network, the bandwidth of moving image data is first reduced to reduce the network load, so that the client device receiving them listens to the voice, which is a more important medium, without reducing the sound quality. It becomes possible. In other words, by using the priority of media transmitted by the server device, transmission data to be subjected to transmission band control is selected from a plurality of transmission data transmitted by the plurality of server devices. The effect that the transmission band can be controlled in an integrated manner is obtained.

[0053] In each of the above embodiments, media transmission using RTP is taken as an example, and RTCP RR (Receiver Report Packet) or SR (Sender Report) multicast transmission status information is transmitted from each client device. Packet). However, it should be understood that the present invention can be applied even when using a proprietary protocol including equivalent contents, not limited to RTCP RRs and SRs. In addition, if a unique protocol is used, it is also possible to directly transmit the transmission status information from each client device to the transmission control device of the present invention by multicast, and the present invention is limited to multicast transmission. It is not something.

Industrial applicability

[0054] As described above, the transmission control device according to the present invention monitors the transmission status on the network and can control the transmission bands of a plurality of server devices in an integrated manner. It is suitable for congestion control of transmission systems.

Claims

The scope of the claims

[1] A transmission control device connected to a network for transmitting transmission data such as moving image data and audio data from a plurality of server devices to a plurality of client devices,

Transmission status information storage means for acquiring transmission status information in the network between the server device and the client device at the start of transmission, during transmission and at the end of transmission, and storing it by registration or update;

The stored transmission status information is monitored, and if a deterioration in the transmission status is detected from the transmission status information, an instruction to lower the transmission bandwidth is sent to all server devices that are transmitting, and a new Server transmission control means for reallocating the transmission bandwidth of each server device when a server device that has started transmission appears and transmitting a transmission bandwidth change command to the server device whose bandwidth has been changed is provided. A transmission control device characterized by that.

[2] server priority information storage means for storing server priority information including priority given in advance to each server device;

Provided in place of the server transmission control means, and when the deterioration of the transmission status is detected from the transmission status information, an instruction to lower the transmission data transmission bandwidth of the server device power with a low priority with reference to the server priority information is provided. 2. The transmission control device according to claim 1, further comprising server transmission priority control means for transmitting to the corresponding server device.

[3] The server priority information storage means stores the server priority corresponding to the transmission data of the corresponding server device according to the priority change notification including the priority of the server after the change received from any server device or any client device. Degree information has changed,

The server transmission priority control means refers to the server priority information after referring to the transmission status information, and when the changed priority is detected, changes the transmission band of the transmission data from the corresponding server device. The transmission control device according to claim 2, wherein a command to be changed based on a later priority is transmitted to the corresponding server device.

[4] Data transmission amount information receiving means for calculating data transmission amount information based on information relating to the transmission rate of each transmission data sequentially received from each server device;

Data transmission amount information storage means for storing each calculated data transmission amount information; A transmission rate of each transmission data sent by each server device with reference to the stored data transmission amount information when a deterioration of the transmission status is detected from the transmission status information. Server transmission priority control that calculates the ratio of the amount of transmission data based on the transmission rate and sends a command to the corresponding server device to reduce the transmission band only for transmission data when the calculated ratio is equal to or greater than a predetermined threshold. The transmission control device according to claim 1, further comprising means.

[5] A transmission request frequency history storage unit that stores the number of transmission requests related to a transmission start request transmitted from the client device to each server device as a transmission request frequency history for each server device;

It is provided in place of the server transmission control means, and when the deterioration of the transmission status is detected from the transmission status information, the transmission request frequency history is referred to, and the transmission request frequency is the lowest value, a predetermined value or less or a predetermined ratio. 2. The transmission control device according to claim 1, further comprising server transmission priority control means for transmitting a command to lower a transmission band only to a certain server device.

[6] The number of transmission client devices for receiving the transmission data of each server device currently transmitted and storing the number of received client devices related to the client device for each server device;

Provided in place of the server transmission control means, and when the deterioration of the transmission status is detected from the transmission status information, the number of receiving client devices is referred to, and the number of devices is the lowest value, below the predetermined value, or at a predetermined ratio. 3. The transmission control device according to claim 2, further comprising server transmission priority control means for transmitting a command for lowering the transmission band only to the server device transmitting to the device.

[7] Client priority storage means for storing client priority information including the priority of each client device in advance;

Provided instead of the server transmission control means, when the deterioration of the transmission status is detected from the transmission status information, the priority of the client device currently transmitting is searched from the client priority information, and the searched priority Decreases the transmission data transmission bandwidth of the server device that is not transmitting to the client device that has the highest value, greater than or equal to the specified value, or in the specified ratio 3. The transmission control device according to claim 2, further comprising server transmission priority control means for transmitting a command to the corresponding server device.

Transmission media information storage means for storing transmission media information including a media type of transmission data transmitted by the server device to the client device at the start of transmission of the server device;

Media priority information storage means for storing in advance media priority information including the media type and the media priority;

It is provided in place of the server transmission control means, and when the deterioration of the transmission status is detected from the transmission status information, each server device transmits the transmission media information from the transmission media information, extracts the media type, and extracts the extracted media type. The media priority is compared with other media information in the media priority information, and if media priority is low and media information exists, the media priority is transmitted and the media information is transmitted. 3. The transmission control device according to claim 2, further comprising server transmission priority control means for transmitting a command to lower the transmission band of transmission data to the server device.