JP5498435B2 - Congestion control device and operation method thereof - Google Patents

Description

  The present invention relates to a congestion control device and an operation method thereof.

  Conventionally, there is a media server having a function of decoding media data files related to audio and video stored in a storage device and transmitting the obtained media stream to a terminal. Used for additional services.

  In general, many processing requests are concentrated on a specific server, the server may be overloaded, and service quality may deteriorate or normal processing may not be possible. A technique for eliminating or avoiding such a congestion state is congestion control.

  For example, Patent Document 2 discloses a method of controlling the number of calls that can be simultaneously connected to the SIP server so that calls exceeding the upper limit are not connected.

  Further, Non-Patent Document 2 proposes and evaluates a method based on call density control for setting the number of new connection permissible calls per unit time to a specified value or less.

  These conventional technologies are intended only for voice call services, and perform congestion control based on the total number of calls without considering the difference in server resources (for example, server processing capacity) required for each call. .

  However, in recent years, videophone services that can transmit not only voice but also video are provided.

  There are various types of videophone terminals, from portable terminals to high-definition videoconferencing terminals, and various codecs such as screen resolution, frame rate, and encoding method are used. Codecs are classified according to the name (encoding name), profile level, bandwidth, and the like of a method for encoding media data files.

  In general, in a media server, the amount of resources consumed when one media data file is decoded by a codec is different for each codec. In particular, when many codecs are used in order to deal with narrow-band audio to wide-band high-definition video, the difference in the amount of resources consumed is large.

  In such a media server, when performing congestion control in which an upper limit is set for the total number of simultaneous connections, that is, the number of media streams transmitted simultaneously, all media streams have the largest amount of resources in order to ensure quality. It is necessary to determine the upper limit value assuming that the codec is consumed. Therefore, if the media server is only sending media streams that can be obtained with a codec that consumes little resources, the congestion control is performed even though the media server resource amount is too large. Since the call connection is restricted, the use efficiency of the media server is deteriorated.

JP 2010-245727 A JP 2009-239550 A

Hayasaka et al., "Development of Melody Call Service", NTT Docomo Technical Journal, Vol.12, No.1, pp.64-69 Ken Kanijima, Koei Matsukawa, Hideaki Horigome, "Evaluation of Congestion Control Method in IP Telephone Network", IEICE Technical Report, TM2007-30 (2007)

  The present invention has been made in view of the above problems, and an object of the present invention is to reach the upper limit of the amount of resources consumed and the amount of resources that can be consumed in a media server using a plurality of codecs. It is an object of the present invention to provide a congestion control device and an operation method thereof that prevent the excessive amount from being excessive.

  In order to solve the above-mentioned problem, the first present invention has a plurality of codecs, decodes a media data file by one of the plurality of codecs, and transmits a media stream obtained. A congestion control device provided in a media server including a transmission unit, wherein for each codec, a weighting factor corresponding to a resource amount consumed by the media server when one media data file is decoded by the codec Can be consumed by the media server, the media data file number storage means for storing the number of media data files indicating the number of media data files decoded by the codec, and the media server. Threshold value that stores the threshold value corresponding to the upper limit resource amount And when the transmission of the media stream is requested, for each codec, the weighting factor for the codec is read from the weighting factor storage unit, and the number of media data files for the codec is stored in the number of media data files Means for calculating the product of the weight coefficient and the number of media data files, and calculating a sum for each codec of the product, and a weight coefficient for the codec for obtaining the requested media stream Is read from the weight coefficient storage means, the threshold value is read from the threshold storage means, the weight coefficient is added to the sum, and media stream transmission availability determination means for determining whether or not the added value is less than the threshold value; If the added value is less than the threshold, the media stream transmission unit On the other hand, a congestion control apparatus comprising: a media stream transmission instruction means for decoding the media data file for obtaining the requested media stream and instructing to transmit the obtained media stream. Means.

  For example, in the first aspect of the present invention, the threshold is the maximum number of packets that can be simultaneously transmitted from the media server, and each weighting factor is a media stream obtained by a codec corresponding to the weighting factor. This is a value obtained by dividing the maximum bandwidth that can be consumed by the size of a packet constituting the media stream.

  For example, in the first aspect of the present invention, the media stream transmission permission / inhibition determining means is configured such that, when a priority order when using a plurality of codecs is specified, the added value is less than the threshold value for each codec. The media stream transmission instructing means selects a codec corresponding to the highest priority from the codecs for which the addition value is determined to be less than the threshold, and sends the codec to the media stream transmission unit. Then, the media data file is decoded by the selected codec, and an instruction is given to transmit the obtained media stream.

  The second aspect of the present invention is provided in a media server that includes a plurality of codecs, decodes a media data file by one of the plurality of codecs, and includes a media stream transmission unit that transmits the obtained media stream. An operation method of a congestion control device, wherein the congestion control device is a weighting factor corresponding to a resource amount consumed by the media server when one media data file is decoded by the codec for each codec. Can be consumed by the media server, the media data file number storage means for storing the number of media data files indicating the number of media data files decoded by the codec, and the media server. Threshold value that stores the threshold value corresponding to the upper limit resource amount Storage means, and when the sum total calculation means of the congestion control device is requested to transmit a media stream, the operation method is configured to obtain a weight coefficient for the codec from the weight coefficient storage means for each codec. Read, read the number of media data files for the codec from the media data file number storage means, determine the product of the weighting factor and the number of media data files, determine the sum of the products for each codec, and A media stream transmission availability determination unit of the control device reads a weighting factor for a codec for obtaining the requested media stream from the weighting factor storage unit, reads a threshold value from the threshold value storage unit, and calculates the weighting factor as the sum Whether or not the added value is less than the threshold value. The media stream transmission instructing means of the congestion control device decodes the media data file for obtaining the requested media stream to the media stream transmitting unit if the added value is less than the threshold value. An operation method of the congestion control device is characterized in that an instruction is given to transmit the media stream.

  For example, in the second aspect of the present invention, the threshold is the maximum number of packets that can be simultaneously transmitted from the media server, and each weighting factor is one media stream obtained by a codec corresponding to the weighting factor. This is a value obtained by dividing the maximum bandwidth that can be consumed by the size of a packet constituting the media stream.

  For example, in the second aspect of the present invention, the media stream transmission permission / inhibition determining means is configured such that, when a priority order for using a plurality of codecs is specified, the added value is less than the threshold for each codec. The media stream transmission instructing means selects a codec corresponding to the highest priority from the codecs for which the addition value is determined to be less than the threshold, and sends the codec to the media stream transmission unit. Then, the media data file is decoded by the selected codec, and an instruction is given to transmit the obtained media stream.

  ADVANTAGE OF THE INVENTION According to this invention, in the media server using a some codec, it can prevent that the amount of resources consumed reaches an upper limit and the amount of resources which can be consumed is not too much.

It is a block diagram of the communication system using the congestion control apparatus which concerns on this Embodiment. 4 is a diagram illustrating an example of a weighting factor stored in a weighting factor storage unit 11. FIG. It is a sequence diagram which shows an example of operation | movement of a communication system.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of a communication system using the congestion control apparatus according to the present embodiment.

  The media server 1 is connected to the call control server 2 and the terminal 3 via an IP network (not shown). In general, there are a plurality of terminals 3.

  The media server 1 is a device that transmits a media stream to the terminal 3 in accordance with call connection control from the call control server 2. For call connection control, a standard call control protocol such as SIP (Session Initiation Protocol) is used.

  The media server 1 includes a congestion control unit 10 and a media playback function unit 20. The congestion control unit 10 is a congestion control device according to the present embodiment.

  The media playback function unit 20 includes a media data file storage unit 21 in which a plurality of media data files are stored and a plurality of codecs, and the media data file read from the media data file storage unit 21 is suitable for the media data file. And a media stream transmitting unit 22 that transmits the media stream obtained by the decoding to the terminal 3.

  The media stream is composed of, for example, an RTP (Real-time Transport Protocol) packet.

  The congestion control unit 10 includes, for each codec, a weighting factor storage unit 11 that stores a weighting factor corresponding to the amount of resources consumed by the media server 1 when one media data file is decoded by the codec, For each codec, a media data file number storage unit 12 storing the number of media data files indicating the number of media data files decoded by the codec, and a threshold corresponding to the upper limit resource amount that can be consumed by the media server 1 are stored. When a call connection request signal is transmitted from the threshold storage unit 13 and the call control server 2, the weighting coefficient for the codec is read from the weighting coefficient storage unit 11 for each codec, and the number of media data files for the codec Is read from the media data file number storage unit 12, A product of weighting factor and the number of media data files is obtained, and a sum calculating unit 14 for obtaining a sum for each codec of the product, and using the calculated sum, whether or not call connection is possible is determined. The communication unit 15 communicates with the call control server 2 to identify a codec to be used when call connection is permitted based on information included in the received call connection request signal. An instruction is given to determine whether or not the call connection is possible, and if the call connection is permitted, a call connection permission signal is transmitted to the call control server 2 and a media stream is transmitted to the media stream transmission unit 22. When the instructing call connection control unit 16 and the call control server 2 complete the call connection and the transmission of the media stream becomes possible, the specification of the media data file number storage unit 12 is performed. While increasing the number of media data files for codec, the call is disconnected, if no longer able to send the media stream, and a media data file speed change section 17 to reduce the number of the media data file.

  The threshold value stored in the threshold value storage unit 13 is, for example, the maximum number of packets that can be simultaneously transmitted from the media server 1.

  In addition to the above processing, the call connection control unit 16 transmits a call connection rejection signal to the call control server 2 when the call connection is rejected. In addition, the call connection control unit 16 excludes the instruction to the call connection possibility determination unit 15, the instruction to the media data file number increase / decrease processing unit 17, and the instruction to the media stream transmission unit 22 so that they are consistent. Take control.

  FIG. 2 is a diagram illustrating an example of the weighting factor stored in the weighting factor storage unit 11. However, the remarks column in the figure is for reference and is not included in the weighting coefficient storage unit 11.

  In the figure, the weighting coefficient storage unit 11 stores a weighting coefficient “50” for a codec named “G.711 μ-law”, and weights for a codec named “MPEG-4 visual SP @ L0”. The coefficient “82” is stored, the weight coefficient “536” is stored for the codec named “MPEG-4 visual SP @ L4a”, and the weight coefficient “536” is stored for the codec named “MPEG-4 visual SP @ L6”. 1866 "is stored.

  When the threshold value stored in the threshold value storage unit 13 is the maximum number of packets that can be simultaneously transmitted from the media server 1, the weighting factors shown in FIG. That is, each weighting factor is a value obtained by dividing the maximum bandwidth that can be consumed by one media stream obtained by the corresponding codec by the size of the packet that constitutes the media stream.

  Specifically, the weighting factor “50” is obtained by dividing the maximum bandwidth that can be consumed by one media stream obtained by the corresponding codec “G.711 μ-law” by the size of the packet constituting the media stream. It is a value obtained by value. Here, the average size of the payload of the packet is calculated as 160 bytes.

  The weighting factor “82” is obtained by dividing the maximum band that can be consumed by one media stream obtained by the corresponding codec “MPEG-4 visual SP @ L0” by the size of the packet constituting the media stream. Value. Here, the average size of the payload of the packet is calculated as 100 bytes.

  The weighting factor “536” is obtained by dividing the maximum band that can be consumed by one media stream obtained by the corresponding codec “MPEG-4 visual SP @ L4a” by the size of the packet constituting the media stream. Value. Here, the average size of the payload of the packet is calculated as 1000 bytes.

  The weighting factor “1866” is obtained by dividing the maximum bandwidth that can be consumed by one media stream obtained by the corresponding codec “MPEG-4 visual SP @ L6” by the size of the packet constituting the media stream. Value. Here, the average size of the payload of the packet is calculated as 1000 bytes.

  Each weighting factor is not limited to a value obtained by dividing the maximum bandwidth that can be consumed by one media stream obtained by the corresponding codec by the size of the packet that constitutes the media stream.

  For example, when the threshold value is a value corresponding to the upper limit processing capability in the media server 1, each weighting factor corresponds to the processing capability used when one media data file is decoded by the corresponding codec. It is good also as a value to do.

(Operation of the communication system according to the present embodiment)
FIG. 3 is a sequence diagram showing an example of the operation of the communication system according to the present embodiment.

  Here, a sequence performed when a media stream is transmitted from the media server 1 to a certain terminal 3 (hereinafter simply referred to as a terminal 3) will be described.

  When the call connection control unit 16 receives the call connection request signal from the call control server 2 (S1), the media information (encoding name, codec profile and level) such as SDP (Session Description Protocol) included in the call connection request signal And the codec information describing each codec that can be used by the media stream transmission unit 22, for example, to specify the codec to be used when the call connection is permitted. Here, it is assumed that a media data file to be decoded is specified when call connection is permitted. The call connection control unit 16 notifies the call connection availability determination unit 15 of the codec type and the like, and instructs to determine whether the call connection is possible (S3).

  Thereby, the call connection possibility determination unit 15 instructs the total calculation unit 14 to calculate the total (S5).

  As a result, for each codec that can be used by the media stream transmission unit 22, the total calculation unit 14 reads the weighting coefficient for the codec from the weighting coefficient storage unit 11, and stores the number of media data files for the codec in the number of media data files. The data is read from the unit 12, and the product of the weighting coefficient and the number of media data files is obtained, the sum of the products for each codec is calculated (S7), and the value of the sum is notified to the call connection possibility determination unit 15 ( S9).

  Thereby, the call connection availability determination unit 15 reads the weighting coefficient for the codec notified from the call connection control unit 16 from the weighting coefficient storage unit 11, reads the threshold value from the threshold storage unit 13, and the weighting coefficient. Is added to the sum notified in step S9, and whether or not call connection is possible is determined based on the added value and the threshold (S11).

  If the added value is less than the threshold value, the call connection availability determination unit 15 notifies the call connection control unit 16 that the call connection is permitted (S13).

  Thereby, the call connection control unit 16 transmits a call connection permission response signal indicating that the call connection is permitted to the call control server 2 (S15).

  Thereby, the call control server 2 performs a call connection between the media server 1 and the terminal 3, and transmits a call connection completion signal indicating that the call connection is completed to the call connection control unit 16 (S17).

  Thus, the call connection control unit 16 notifies the media data file number increase / decrease processing unit 17 of the type of codec identified in step S3, and the number of media data files for the codec in the media data file number storage unit 12 Is instructed to add 1 to (S19).

  As a result, the media data file number increase / decrease processing unit 17 adds 1 to the media data file number for the notified codec in the media data file number storage unit 12, and sends the number of media data files to the call connection control unit 16. Is notified that 1 has been added (S21).

  Thereby, the call connection control unit 16 decodes the media data file specified in step S3 with respect to the media stream transmission unit 22 by the codec specified in step S3, and sends the media stream obtained by the decoding to the terminal 3. An instruction is given to transmit (S23).

  Accordingly, the media stream transmission unit 22 reads the media data file from the media data file storage unit 21, decodes the media data file with the codec, and transmits the media stream obtained by the decoding to the terminal 3.

  That is, if the added value obtained by adding the weighting factor for the codec used when call connection is permitted to the sum is less than the threshold corresponding to the upper limit resource amount that can be consumed by the media server 1, call connection is permitted. Thus, congestion can be prevented and inconvenience of excessive resource amount can be prevented.

  The call control server 2, for example, terminates the transmission of the media stream to the terminal 3, and if there is a call disconnect request from the terminal 3, the call control server 2 disconnects the call and indicates a call disconnect completion signal indicating completion of the call disconnection. Is transmitted to the call connection control unit 16.

  As a result, the call connection control unit 16 notifies the media data file number increase / decrease processing unit 17 of the type of codec identified in step S3 and instructs to subtract 1 from the number of corresponding media data files. .

  Thereby, the media data file number increase / decrease processing unit 17 subtracts 1 from the media data file number for the codec in the media data file number storage unit 12.

  The call connection availability determination unit 15 notifies the call connection control unit 16 that the call connection is rejected if the added value is equal to or greater than the threshold value.

  As a result, the call connection control unit 16 transmits a call connection rejection response signal indicating that the call connection is rejected to the call control server 2.

  As a result, the call control server 2 stops the call connection between the media server 1 and the terminal 3. Therefore, decoding of the media data file and transmission of the media stream are also stopped.

  Therefore, according to the congestion control apparatus (10) according to the present embodiment, it has a plurality of codecs, decodes a media data file by one of the plurality of codecs, and transmits the obtained media stream. A congestion control device provided in the media server 1 including the media stream transmission unit 22 and corresponding to the amount of resources consumed by the media server 1 for each codec when one media data file is decoded by the codec Weight coefficient storage means (11) for storing the weight coefficient to be stored, and media data file number storage means (12) for storing the number of media data files indicating the number of media data files decoded by the codec for each codec And the maximum amount of resources that can be consumed by the media server 1 A threshold storage unit (13) that stores a corresponding threshold value, and when a transmission of a media stream is requested (step S1), for each codec, a weighting factor for the codec is read from the weighting factor storage unit (11), The number of media data files for the codec is read from the media data file number storage means (12), and the product of the weighting coefficient and the number of media data files is obtained, and the sum of the products for each codec is obtained (step S7). The summation calculation means (14) and the weighting coefficient for the codec for obtaining the requested media stream are read from the weighting coefficient storage means (11), the threshold value is read from the threshold value storage means (13), and the weighting coefficient is summed. Addition is performed and it is determined whether or not the added value is less than the threshold value (step S11). Media stream transmission availability determination means (15), and if the added value is less than the threshold value, the media stream transmission unit 22 decodes the media data file for obtaining the requested media stream, and transmits the obtained media stream. Media stream transmission instructing means (16) for instructing to do so, it is possible to prevent the amount of resources consumed in the media server 1 from reaching the upper limit and the amount of resources that can be consumed from being excessive, Therefore, it is possible to prevent congestion related to the transmission of the media stream caused by the resource amount reaching the upper limit, and to prevent the resource amount from being excessive.

(Modification)
In the present embodiment, one codec is identified by the information included in the call connection request signal, the media data file corresponding to the codec is decoded by the codec, and the obtained media stream is transmitted. You may do it.

  For example, the media data file storage unit 21 stores, for each of a plurality of codecs, a media data file to be decoded by the codec.

  The media stream transmission unit 22 has the codecs.

  In the call connection request signal, the priority order when using each codec is specified.

  In this case, the call connection availability determination unit 15 determines whether or not the added value is less than the threshold for each codec, and the call connection control unit determines the type of codec determined to be less than the threshold. 16 is notified.

  The call connection control unit 16 selects a codec corresponding to the highest priority designated for the notified codec, and sends a media data file corresponding to the selected codec to the media stream transmission unit 22 by the codec. Decode and instruct to send the resulting media stream.

  The media stream transmission unit 22 reads the media data file corresponding to the codec from the media data file storage unit 21, decodes the media data file with the codec, and transmits the obtained media stream to the terminal 3.

  Therefore, according to this modification, the media stream transmission availability determination means (15) has an addition value less than the threshold value for each codec when the priority order when using a plurality of codecs is designated. The media stream transmission instruction means (16) selects the codec corresponding to the highest priority from the codecs for which the addition value is determined to be less than the threshold value, and sends the codec to the media stream transmission unit 22 Since the media data file is decoded by the selected codec and an instruction is given to transmit the obtained media stream, the codec corresponding to the highest priority among the plurality of codecs can be used.

  The computer program for causing the computer to function as the congestion control device (10) according to the present embodiment can be recorded on a computer-readable recording medium such as a semiconductor memory, a magnetic disk, an optical disk, a magneto-optical disk, or a magnetic tape. Further, it can be widely distributed by being transmitted through a communication network such as the Internet.

DESCRIPTION OF SYMBOLS 1 ... Media server 2 ... Call control server 3 ... Terminal 10 ... Congestion control part 11 ... Weight coefficient memory | storage part 12 ... Media data file number memory | storage part 13 ... Threshold memory | storage part 14 ... Sum total calculation part 15 ... Call connection availability determination part 16 ... Call connection control unit 17 ... Media data file number increase / decrease processing unit 20 ... Media playback function unit 21 ... Media data file storage unit 22 ... Media stream transmission unit

Claims (7)

A congestion control device provided in a media server having a plurality of codecs, decoding a media data file by one of the plurality of codecs, and including a media stream transmission unit for transmitting the obtained media stream,
For each codec, weight coefficient storage means for storing a weight coefficient corresponding to the amount of resources consumed by the media server when one media data file is decoded by the codec;
Media data file number storage means for storing the number of media data files indicating the number of media data files decoded by the codec for each codec;
Threshold storage means for storing a threshold corresponding to an upper limit resource amount that can be consumed by the media server;
When transmission of a media stream is requested, for each codec, the weighting coefficient for the codec is read from the weighting coefficient storage means, and the number of media data files for the codec is read from the media data file number storage means, A sum calculating means for obtaining a product of the weighting coefficient and the number of media data files and obtaining a sum of the products for each codec;
A weighting factor for a codec for obtaining the requested media stream is read from the weighting factor storage unit, a threshold value is read from the threshold value storage unit, the weighting factor is added to the sum, and the added value is less than the threshold value. Media stream transmission availability determination means for determining whether or not there is,
If the added value is less than the threshold value, a media stream transmission instruction for instructing the media stream transmission unit to decode a media data file for obtaining the requested media stream and to transmit the obtained media stream And a congestion control device. The threshold is the maximum number of packets that can be transmitted simultaneously from the media server,
Each of the weighting factors is a value obtained by dividing the maximum bandwidth that can be consumed by one media stream obtained by a codec corresponding to the weighting factor by the size of a packet constituting the media stream. 1. The congestion control device according to 1. The media stream transmission availability determination unit determines whether or not the added value is less than the threshold for each codec when a priority order when using a plurality of codecs is designated,
The media stream transmission instruction means selects a codec corresponding to the highest priority from the codecs for which the addition value is determined to be less than the threshold value, and sends a media code to the media stream transmission unit according to the selected codec. The congestion control apparatus according to claim 1, wherein the data file is decoded and an instruction is given to transmit the obtained media stream. An operation method of a congestion control apparatus provided in a media server having a plurality of codecs, decoding a media data file by one of the plurality of codecs, and including a media stream transmission unit for transmitting the obtained media stream There,
The congestion control device includes:
For each codec, weight coefficient storage means for storing a weight coefficient corresponding to the amount of resources consumed by the media server when one media data file is decoded by the codec;
Media data file number storage means for storing the number of media data files indicating the number of media data files decoded by the codec for each codec;
Threshold storage means for storing a threshold corresponding to the upper limit resource amount that can be consumed by the media server,
The operation method is as follows:
When the sum calculation means of the congestion control device is requested to transmit a media stream, for each of the codecs, the weight coefficient for the codec is read from the weight coefficient storage means, and the number of media data files for the codec is calculated. Read from the media data file number storage means, determine the product of the weighting coefficient and the number of media data files, determine the sum of the product for each codec,
The media stream transmission availability determination means of the congestion control device,
A weighting factor for a codec for obtaining the requested media stream is read from the weighting factor storage unit, a threshold value is read from the threshold value storage unit, the weighting factor is added to the sum, and the added value is less than the threshold value. Determine if there is,
Media stream transmission instruction means of the congestion control device,
If the added value is less than the threshold value, the media stream transmission unit is instructed to decode the media data file for obtaining the requested media stream and to transmit the obtained media stream. Method of operation of the congestion control device. The threshold is the maximum number of packets that can be transmitted simultaneously from the media server,
Each of the weighting factors is a value obtained by dividing the maximum bandwidth that can be consumed by one media stream obtained by a codec corresponding to the weighting factor by the size of a packet constituting the media stream. 5. The operation method of the congestion control device according to 4. The media stream transmission availability determination unit determines whether or not the added value is less than the threshold for each codec when a priority order when using a plurality of codecs is designated,
The media stream transmission instruction means selects a codec corresponding to the highest priority from the codecs for which the addition value is determined to be less than the threshold value, and sends a media code to the media stream transmission unit according to the selected codec. The operation method of the congestion control device according to claim 4 or 5, wherein an instruction is given to decode the data file and transmit the obtained media stream.   A computer program for causing a computer to function as the congestion control device according to claim 1.

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