JP5064434B2 - Communication control device and communication control method - Google Patents

Description

  The present invention relates to a communication control apparatus and a communication control method for relaying information communication via a communication line.

  In recent years, communication technologies such as ADSL (Asymmetric Digital Subscriber Line), VDSL (Very High Bitrate Digital Subscriber Line), and FTTH (Fiber To The Home) have become widespread, and various types of information are communicated via broadband communication lines. . In such a communication line, not only character data and still image data are communicated, but also, for example, audio data by IP (Internet Protocol) packets or video data is streamed in video distribution and transmitted continuously without interruption. Communication of required information is performed. Here, since the communication speed of the communication line has a physical limit, when information exceeding the bandwidth of the relay line corresponding to the communication speed of the communication line is input, it is associated with the type of the information QoS (Quality of Service) technology for performing control according to priority has been studied.

  In such priority control by QoS, for each type of information to be transmitted, a priority class is determined according to the degree to which delay or loss is allowed when the information is transmitted. The determined priority class is stored in a communication control device that relays information from the communication line on the transmission side to the communication line on the reception side. When the amount of information per unit time received via the communication line on the transmission side exceeds the amount of information that can be relayed to the communication line on the reception side per unit time, the communication control device supports a lower priority class. The attached type information is discarded, and information associated with a higher priority class is transmitted with priority. By associating information types that require sustainability with such priority control with high priority classes, even when a large amount of information is sent to the communication line, information that requires sustainability is interrupted. You can relay without.

  By the way, in Non-Patent Documents 1 to 3, when such a communication control device decreases so that the signal-to-noise ratio (SNR) of the communication line decreases and the SNR falls below the lower limit reference value. SRA (Seamless Rate Adaptation) function for increasing the SNR by lowering the communication speed and controlling the communication speed to increase to decrease the SNR if it increases to exceed the upper limit reference value, An SOS function for controlling the communication speed to decrease immediately when a decrease (abrupt increase in noise) is detected is described.

“ITU-T Recommendation G.993.2 Amenment 3”, TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU, August 2008 “ITU-T Recommendation G.993.2”, TELECOMMUNICATION STANDARDIZATION SECTION OF ITU, February 2006 “ITU-T Recommendation G.994.1”, TELECOMMUNICATION STANDARDIZATION SECTION OF ITU, May 2003

  However, the priority control according to the prior art takes into account information other than the type associated with the lower priority class when the communication speed of the transmission side communication line exceeds the communication speed of the reception side communication line. Since there are a plurality of flows of the same type and associated with the same priority class, any one of the plurality of flows is randomly discarded. For example, in the state where different videos are transmitted to the same communication line by two flows in multicast, when the reception speed exceeds the transmission speed, the same type of information is randomly discarded every unit time. Both videos will be disturbed. For example, if a bandwidth of 10 Mbps (Mega bit per second) is required per flow for distributing moving images, both moving images can be transmitted when the bandwidth of the communication line on the receiving side exceeds 20 Mbps. However, when the bandwidth of the communication line on the receiving side is reduced to 20 Mbps or less due to the influence of noise or the like, the information of one of the flows is randomly discarded every unit time, and the communication quality of both flows decreases. . In particular, it is conceivable that such a situation is likely to occur in a communication environment in which the communication speed changes flexibly according to noise by the SRA function or the SOS function.

  The present invention has been made in view of such a situation, and the communication speed is changed due to the influence of noise or the like, so that the reception speed exceeds the transmission speed, and the communication speed in the communication line on the reception side is relatively lowered. In this case, a communication control device and a communication control method are provided for preventing the influence on the communication quality due to the communication speed drop from affecting all the flows in the communication line on the receiving side.

In order to solve the above-described problem, the present invention provides information transmitted from a transmission-side device connected via a transmission-side communication line as a destination of information connected via a reception-side communication line. A communication control device that transmits to a receiving device, a receiving unit that receives a plurality of flows of information transmitted from the transmitting device, a receiving speed calculating unit that calculates a receiving speed at which the receiving unit receives information, The transmission unit that transmits the flow of information received by the reception unit to the reception side device, the transmission rate calculation unit that calculates the transmission rate at which the transmission unit transmits information, and the reception rate that is calculated by the reception rate calculation unit is A communication speed determination unit that determines whether or not the transmission speed calculated by the speed calculation unit is exceeded, and a plurality of flows received by the reception unit when the communication speed determination unit determines that the reception speed exceeds the transmission speed Out of Determines because was flow as a flow stop target, is determined and the flow control unit stopping, placed downstream than the flow control unit, among the plurality of flow received by the receiver, as a stop target by the flow control unit A priority control unit that performs priority control on information corresponding to a flow other than the flow that has been transmitted, and information corresponding to a flow other than the flow that is determined as a stop target is transmitted by the transmission unit according to priority control by the priority control unit. And a communication control unit.

  Further, the present invention is characterized in that the reception speed calculation unit measures the amount of information received by the reception unit every unit time, and calculates the reception speed based on the measurement result.

  Further, the present invention relates to a flow communication speed in which an information type indicating a type of information transmitted from a transmission side apparatus and a flow communication speed indicating a communication speed of a flow corresponding to the information type information are stored in association with each other. The flow rate reading unit includes a storage unit, and the reception rate calculation unit reads out the flow communication rate associated with the information type of the flow received by the reception unit from the flow communication rate storage unit, and reads out the flow communication rate for each information type of a plurality of flows. The reception speed is calculated based on the speed.

  In addition, the present invention provides whether or not the transmission speed calculated by the transmission speed calculation unit exceeds a predetermined threshold after the communication speed determination unit determines that the flow is a stop target by the flow control unit. The flow control unit determines to resume transmission of the predetermined flow to be stopped when the communication speed determination unit determines that the transmission information amount exceeds a predetermined threshold, and performs communication control. The unit is characterized in that the transmission unit transmits information corresponding to the flow determined to resume transmission by the flow control unit.

Further, the present invention provides communication for transmitting information transmitted from a transmission-side device connected via a transmission-side communication line to a reception-side device that is a destination of information connected via the reception-side communication line. A communication device control method for a control device, wherein a reception unit receives a plurality of flows of information transmitted from a transmission-side device, and a reception rate calculation unit calculates a reception rate at which information is received by the reception unit step and step, the transmission unit, and transmitting the flow of information received by the receiving unit to the receiving apparatus, the transmission rate calculation section calculates the transmission rate of information I by the transmission section are transmitted to A step in which the communication speed determination unit determines whether or not the reception speed calculated by the reception speed calculation unit exceeds the transmission speed calculated by the transmission speed calculation unit; Therefore, if the reception speed is determined to exceed the transmission rate among a plurality of flow received by the receiver, the flow defined determined as a flow stop target, the method comprising: stopping, stage after the flow control unit The priority control unit installed in the network performs priority control on information corresponding to a flow other than the flow determined to be stopped by the flow control unit among a plurality of flows received by the reception unit; and communication And a step of causing the transmission unit to transmit information corresponding to a flow other than the flow determined as a stop target according to the priority control by the priority control unit.

  As described above, according to the present invention, the communication control apparatus receives the information flow transmitted from the transmission side apparatus, calculates the reception speed for receiving the information, and determines the received information flow as the reception side apparatus. If the reception speed exceeds the transmission speed, the transmission speed is determined from among the received flows. Since the flow corresponding to the flow other than the flow determined as the stop target is transmitted to the receiving side device, the transmission speed decreases due to the occurrence or increase of noise, for example. Even if the reception speed exceeds the transmission speed, by stopping the transmission of information by the specified flow, the effect of the decrease in communication speed on other flows is absorbed, and It is possible to prevent a decrease in communication speed.

It is a figure which shows the outline | summary of the communication system by one Embodiment of this invention. It is a block diagram which shows the structure of the communication system by one Embodiment of this invention. It is a figure which shows the example of data memorize | stored in the flow control part by one Embodiment of this invention. It is a figure which shows the concept of the priority control by the priority control part of one Embodiment of this invention. It is a figure which shows the concept of the control performed by the SRA control part by one Embodiment of this invention. It is a figure which shows the concept of the control performed by the SRA control part by one Embodiment of this invention. It is a figure which shows the change of the communication speed corresponding to the change of the conventional communication state, and the change of the communication speed corresponding to the change of the communication state using a SRA function and a SOS function. It is a flowchart which shows the operation example of the communication system by one Embodiment of this invention. It is a flowchart which shows the operation example of the communication system by one Embodiment of this invention. It is a figure which shows the operation | movement outline | summary of the communication system by one Embodiment of this invention. It is a block diagram which shows the structure of the communication system by one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing an overview of a communication system 1 according to the present embodiment. The MDF (Main Distributing Frame) 410 installed in the manager room of the apartment house 20 such as an apartment is connected to the exchange 110 of the exchange 10 via a metallic cable communication line, and the exchange 110 is connected to the telephone network. The The VDSL collective device 200 installed in the manager room of the apartment 20 is connected to an optical fiber cable via an optical access device 420, and the optical fiber cable is connected to a station side device (optical access device) 100. The station side device 100 is connected to an IP network. The VDSL collective device 200 is connected to the MDF 410, and the MDF 410 is connected to the VDSL modem 320 installed in the house via the premises metal cable of the collective housing 20. The VDSL modem 320 is connected to a terminal device 300-via a home communication device (HGW (Home GateWay)) 310-1 or a home communication device (VOIP (Voice over IP) terminal) 310-2 that realizes voice communication by IP technology. 1 and the terminal device 300-2.

FIG. 2 is a block diagram illustrating a configuration of the communication system 1 according to the present embodiment.
In the present embodiment, one station-side device 100, one VDSL aggregation device 200, and one VDSL modem 320 are illustrated and described, but a plurality of units are provided for one station-side device 100. The VDSL apparatus 200 may be connected, or a plurality of VDSL modems 320 may be connected to one VDSL apparatus 200. In this case, each part of the VDSL apparatus 200 performs a flow control process for each connected VDSL modem 320.

The station-side device 100 is a communication device on the transmission side that relays information transmitted and received by the terminal device 300-1 or the terminal device 300-2.
The VDSL aggregation device 200 is a communication device that communicates with the station-side device 100 connected via a communication line. The VDSL aggregation device 200 receives the information flow transmitted from the station-side device 100 and transmits the received information to the terminal device 300 that is the destination of the information. The VDSL aggregation device 200 includes a reception unit 210, a reception speed calculation unit 220, a communication speed determination unit 230, a flow control unit 240, a priority control unit 250, a communication control unit 260, a transmission unit 270, and a bandwidth monitor. 280.

The receiving unit 210 receives a plurality of flows transmitted from the station side device 100 via a communication line. Here, the flow refers to information transmitted / received for each channel determined by the type of information.
The reception speed calculation unit 220 calculates a reception speed at which the reception unit 210 receives information. Here, the reception speed calculation unit 220 calculates the reception speed of the flow per VDSL modem 320 that is the information transmission destination. For example, the reception speed calculation unit 220 measures the amount of information per transmission destination (VDSL modem 320) received by the reception unit 210 per unit time, and calculates the reception speed based on the measurement result. The unit of the reception speed is, for example, Mbps.

  The communication speed determination unit 230 compares the reception speed calculated by the reception speed calculation unit 220 with the transmission speed to the reception-side communication line calculated by the band monitor 280 described later. Also, the communication speed determination unit 230 determines whether the reception speed calculated by the reception speed calculation unit 220 exceeds the transmission speed calculated by the band monitor 280 based on the comparison result.

  When the communication speed determination unit 230 determines that the reception speed exceeds the transmission speed, the flow control unit 240 determines a predetermined flow among a plurality of flows received from the station side device 100 as a stop target. The flow control unit 240 discards the information transmitted by the flow determined as the stop target and performs control so that the communication control unit 260 does not transmit the information. Here, the flow to be stopped by the specific flow stop unit 240 may be stored in advance in the storage area of the flow control unit 240. For example, for each of a plurality of flows, transmission of information by the flow may be performed. You may make it determine based on the measured elapsed time by measuring the elapsed time after starting.

  When determining the flow to be stopped based on the elapsed time, the flow transmission table and the time table are stored in the storage area of the flow control unit 240 as shown in FIG. In the flow transmission table, transmission permission / inhibition information (flag) indicating whether or not transmission is performed for each flow is stored in association with each other. For example, when the transmission permission / inhibition information is “ON”, it indicates that information is transmitted through the corresponding flow. When the transmission permission / inhibition information is “OFF”, information is transmitted through the corresponding flow. Indicates no. In the time table, for each flow stored in the flow transmission table, a time at which communication by the flow is started and a time value indicating an elapsed time from the start time are stored. If the time value is large, it indicates that the elapsed time from the time when communication is started by the flow is long, and if the time value is small, it indicates that the elapsed time from the time when communication is started by the flow is short. As shown in FIG. 3A, if both the flow 1 and the flow 2 are “ON” and the time value of the flow 1 is larger than the time value of the flow 2, the flow control unit 240 displays the time value. The flow 2 having a small number is determined as a flow to be stopped. The flow control unit 240 discards information corresponding to the flow determined as the information stop target and stops transmission to the priority control unit 250. Here, the flow control unit 240 uses, for example, information indicating a source IP address, a destination IP address, a source port number, a destination port number, an input interface, and the like included in the header part of the packet received by the receiving unit 210. Identify the type of information. Further, the identification of information for each flow may have an identification method specialized for a specific application such as identification by other packet identifiers, MLD (Multicast listener Discovery), or the like.

  The priority control unit 250 performs priority control of information transmitted from the VDSL aggregation device 200 to the terminal device 300 in accordance with a correspondence between a predetermined priority class and an information type. For example, the priority control unit 250 stores the priority class of the information type indicated in the header of the IP packet, for example, and further stores the information type for each priority class. For example, as a priority class, three classes of a low priority (L) class, a priority (M) class, and a high priority (H) class are stored. Here, the type of information whose sustainability is low without being interrupted is associated with a lower priority class, and the type of information whose sustainability is high without being interrupted Is associated with a higher priority class. For example, an information type such as character data or a still image is associated with the low priority (L) class. The priority (M) class is associated with an information type such as a moving image by streaming distribution. The high priority (H) class is associated with an information type such as voice data by IP telephone communication. The priority control unit 250 monitors the communication speed of the communication line to which information is transmitted by the communication control unit 260, and the reception speed of the information received by the reception unit 210 is greater than the transmission speed of the information transmitted from the communication control unit 260. If it is larger, the information to be discarded is randomly determined from the information associated with the type having a lower priority class, and the information determined to be discarded is discarded. Here, the priority control unit 250 uses, for example, information indicating a transmission source IP address, a destination IP address, a transmission source port number, a destination port number, an input interface, and the like included in the header of the packet received by the reception unit 210. Identify the type of information. Also. Information for each flow may be identified by other packet identifiers, MLD (Multicast listener Discovery), or the like.

  For example, as shown in FIG. 4, when the receiving unit as a whole is receiving at the speed of S0, when each class and flow distribution is stacked from the highest priority (H) class, each class and flow are assigned to each other. It is assumed that the communication speed S0, the communication speed Sa, the communication speed Sb, the communication speed Sc, and the communication speed Sd accumulated one by one are in a relationship of S0> Sa> Sb> Sc> Sd. Here, when the transmission speed of information transmitted from the communication control unit 260 is the communication speed S, when the communication speed S is smaller than S0 and larger than Sa (S0> S> Sa), low priority (L). Information on the type corresponding to the class is randomly discarded by the priority control unit 250. Similarly, when the communication speed S is smaller than Sa and larger than Sc (Sa> S> Sc), all of the types of information corresponding to the low priority (L) class and the priority (M) class are supported. Information randomly determined from the type information is discarded by the priority control unit 250. Similarly, when the communication speed S is smaller than Sc (Sc> S), all types of information corresponding to the low priority (L) class and the priority (M) class and the high priority (H) class are supported. The information randomly determined from the type of information to be discarded is discarded by the priority control unit 250. In general, since the priority control unit ensures high-speed operation, it is difficult to have many standards for identifying the priority of information to be received. For example, as shown in FIG. 4, the priority of only the three classes of H, M, and L is determined to operate at high speed. Therefore, in the present embodiment, the flow control unit 240 is arranged in view of the difficulty of identifying many flows having the same priority and performing priority control flexibly in the prior art.

Returning to FIG. 2, the communication control unit 260 includes an SNR measurement unit 261, an SRA control unit 262, and an SOS control unit 263, and transmits information received by the reception unit 210 from the communication line on the transmission side. A control process of VDSL communication to be transmitted to the communication line on the receiving side by 270 is performed.
The SNR measurement unit 261 measures the SNR in the communication line through which the transmission unit 270 transmits information to the VDSL modem 320.

  The SRA control unit 262 controls the SRA function in VDSL. The SRA function increases the communication speed with the VDSL modem 320 if the SNR measured within a predetermined time by the SNR measurement unit 261 increases beyond a predetermined SNR upper limit reference value, and is determined in advance. If it is below the SNR lower limit reference value, control is performed to lower the communication speed. Here, increase / decrease in the communication speed is controlled by changing the number of bits of information transmitted per unit time, for example.

  For example, FIG. 5 is a diagram illustrating a concept of control performed by the SRA control unit 262 when the SNR measured by the SNR measurement unit 261 decreases with time and the amount of noise increases. In the figure, the Y-axis indicates the SNR, and the higher the value is, the higher the SNR and the smaller the amount of noise. For example, when the SNR is at the point indicated by the symbol a, the SNR margin exceeding the SNR lower limit reference value can be maintained. The SNR margin is a difference between a lower limit reference value for performing communication maintaining a predetermined communication quality and an SNR exceeding the lower limit reference value, and is more than a certain value (for example, 1 dB) for stable communication. It is desirable to maintain a high SNR margin. From the point indicated by the symbol a, the SNR measurement unit 261 measures that the noise amount increases due to an external factor and decreases toward the symbol b. In this case, if the SRA control unit 262 determines that the SNR of the code b below the SNR lower limit reference value has continued for a predetermined time (for example, 5 seconds), the communication speed is reduced. As a result, the SNR increases from the code c to the code d, and the SNR margin is recovered.

  In contrast, FIG. 6 is a diagram illustrating a concept of control performed by the SRA control unit 262 when the SNR measured by the SNR measurement unit 261 increases with time and the amount of noise decreases. For example, the SNR measurement unit 261 measures that the SNR increases toward the code b due to an external factor from the point indicated by the code a, and the noise amount decreases. In this case, when the SRA control unit 262 determines that the SNR of the code b below the SNR upper limit reference value has continued for a predetermined time (for example, 5 seconds), the communication rate of the transmission unit 270 is increased. As a result, the SNR decreases from the code c to the code d, and communication can be performed at an appropriate communication speed according to the SNR state of the communication line without taking too much SNR margin.

  Returning to FIG. 2, the SOS control unit 263 controls communication with the VDSL modem 320 so as to immediately decrease the communication speed when detecting a rapid increase in SNR. The SOS operates according to user settings, for example, when a plurality of communication errors are detected within a certain period of time, or when there is a change in SNR exceeding a threshold value within a certain period of time. To reduce the communication speed. In other words, SRA is a function that changes the communication speed in response to a gradual change in SNR over time, such as 5 seconds, while SOS is designed to prevent errors in response to sudden changes in external factors. This is a function of quickly changing the communication rate to lower the communication speed and ensuring the SNR margin. For example, when the noise level suddenly increases, an error may also occur in the communication flow, so that even a parameter for changing the communication speed may not be transmitted / received. It may be difficult to do. According to the SOS function, when such a sudden change in external factor occurs, the communication speed can be quickly reduced and the link can be maintained.

  FIG. 7 is a diagram illustrating a change in communication speed corresponding to a change in conventional communication state and a change in communication speed corresponding to a change in communication state using the SRA function and the SOS function. As shown in FIG. 7A, conventionally, when an increase in noise or the like occurs and communication quality determined due to frequent errors or the like cannot be maintained, link disconnection occurs and retraining is performed. Communication is resumed at a reduced communication speed. As shown in FIG. 7B, when the SRA function and the SOS function are used, the communication speed is decreased instantaneously by the SOS function when noise increases, and then the communication speed is gradually increased by the SRA function according to the communication state. As a result, even if the noise suddenly increases, it is possible to maintain the communication connection state without causing retraining or link disconnection.

Returning to FIG. 2, the transmission unit 270 transmits the information received by the reception unit 210 to the VDSL modem 320 in accordance with a control instruction from the communication control unit 260.
Band monitor 280 calculates a transmission rate at which transmission unit 270 transmits information. For example, the bandwidth monitor 280 measures the amount of information that the receiving unit 210 transmits per unit time, and calculates a communication speed in units of Mbps.
The VDSL modem 320 is a communication device installed in the house, and performs communication with the aggregation device 200 in accordance with the VDSL transmission method.

  The in-home communication device 310-1 and the in-home communication device 310-2 are communication devices that connect a VDSL modem and a terminal device outside the home. For example, HGW, STB (Set Top Box), or the like can be applied. Since in-home communication device 310-1 and in-home communication device 310-2 have the same configuration, in the following description, it will be described as in-home communication device 310 when it is not necessary to distinguish between them. Here, although two in-home communication devices 310 are illustrated in the figure, the in-home communication device 310 installed in the home may be one, or three or more in accordance with the communication environment of the user's home. Multiple units may be installed.

  The terminal device 300-1 and the terminal device 300-2 are communication devices installed in the home, and receive information transmitted via the VDSL aggregation device 200. As the terminal device 300, for example, a PC (Personal Computer) that reproduces transmitted moving image information, an IP telephone terminal that performs IP telephone communication, or the like can be applied. Since the terminal device 300-1 and the terminal device 300-2 have the same configuration, in the following description, the terminal device 300-1 and the terminal device 300-2 will be described as the terminal device 300 when it is not necessary to distinguish them. Here, although two terminal devices 300 are illustrated in the figure, the number of terminal devices 300 installed in the home may be one, or three or more terminal devices depending on the communication environment of the user's home. 300 may be installed.

Next, an operation example of the communication system 1 according to the present embodiment will be described. FIG. 8 is a flowchart illustrating an operation example of communication control performed by the communication system 1 of the present embodiment.
Here, transmission of information from the station side device 100 to the terminal device 300 is started, and SRA processing by the SRA control unit 262 of the communication control unit 260 and SOS processing by the SOS control unit 263 are performed (step). S1). Through the SOS or SRA process, the communication speed at which the transmission unit 270 transmits information decreases (step S2). The bandwidth monitor 280 calculates the communication speed of the transmission unit 270 and outputs it to the communication speed determination unit 230. The communication speed determination unit 230 determines whether or not the transmission speed S calculated by the bandwidth monitor 280 is smaller than the communication speed threshold value Sa of the priority (M) class and larger than the communication speed Sb (step S3). Here, when the communication speed determination unit 230 determines that the communication speed S is lower than the communication speed Sa and not higher than the communication speed Sb (step S3: NO), the process is terminated.

  In step S3, when the communication speed determination unit 230 determines that the communication speed S is lower than the communication speed Sa and higher than the communication speed Sb (step S3: YES), the flow control unit 240 determines the priority (M). It is determined that transmission of any of the types of information associated with the class is stopped (step S4). The flow control unit 240 determines which flow information among a plurality of flows corresponding to the type of the priority (M) class determined to be stopped, and sets the information determined as the discard target. Discard (step S5).

  Similarly, the VDSL aggregation device 200 is stopped when the transmission rate calculated by the bandwidth monitor 280 exceeds a predetermined threshold after the flow control unit 240 stops transmission of information by any flow. Resume flow transmission. For example, FIG. 9 is a flowchart illustrating an operation example of the VDSL aggregation device 200 when information transmission is resumed in this way.

  When the SNR measured by the SNR measurement unit 261 increases and the SRA control unit 262 executes the SRA process (step S11), the communication speed of the transmission unit 270 increases (step S12). If the communication speed determination unit 230 determines that the transmission speed S calculated by the bandwidth monitor 280 is greater than the communication speed Sa, the flow control unit 240 resumes information transmission of the flow for which information transmission has been stopped in step S5. Then, it determines (step S14). Then, the transmission unit 270 resumes information transmission of the flow that has been stopped in step S5 (step S15).

  FIG. 10 is a diagram showing the concept of the communication system 1 that operates in this way. Here, the VDSL aggregation device 200 transmits the moving image information of the flow 1 and the moving image information of the flow 2 transmitted from the higher-level device (for example, the station side device 100) to the terminal device (TV) 300- via the VDSL modem 320. 1 and the terminal device (TV) 300-2. The bandwidth monitor 280 measures the transmission speed of the information transmitted by the transmission unit 270. When the transmission rate (output band) of the transmission unit 270 decreases due to the SRA and SOS functions operating due to the influence of noise or the like (symbol a → symbol b), the flow control unit 240 stops the distribution of the flow 2. . The priority control unit 250 receives a flow of a high priority (H) class, a flow 1 except for a flow 2 among flows of a priority (M) class, and a flow of a low priority (L) class. The priority control unit 250 discards a packet with a low priority (L) class flow by priority control. As a result, the packet of the flow 1 excluding the packet of the flow 2 in the priority (M) class information is transmitted to the terminal device 300-1 without being discarded by the priority control unit 250, and a certain level of communication quality is maintained. Is done. Since the transmission of the flow 2 is stopped, the moving image information is not transmitted to the terminal device 300-2.

<Second Embodiment>
Next, a second embodiment of the present invention will be described. FIG. 11 is a block diagram illustrating a configuration of the communication system 1 according to the present embodiment. The configuration of the communication system 1 according to this embodiment is the same as that of the first embodiment, but the VDSL aggregation device 200 includes a flow communication speed storage unit 290. The flow communication speed storage unit 290 stores an information type indicating the type of information transmitted from the station side device 100 and a flow communication speed indicating a communication speed of a flow corresponding to the information of the information type in association with each other. The

  In the first embodiment, the reception speed calculation unit 220 calculates the reception speed by measuring the communication speed of the communication line on the transmission side from which the reception unit 210 receives information. The flow communication speed associated with the information type of a plurality of information flows transmitted from the station-side apparatus 100 is read from the flow communication speed storage unit 290, and the information amount corresponding to the communication speed read for each of the plurality of flows The reception speed is calculated based on the total amount.

  For example, in the flow communication speed storage unit 290, a communication speed (bandwidth) necessary for each flow in order to transmit information of the information type for each information type is stored in association with each other. For example, when the information type is “video distribution”, a bandwidth of “10 Mbps” per flow is associated with a bandwidth such as “20 Mbps” per flow when it is “high quality video distribution”. Is remembered. The flow communication speed storage unit 290 determines an information type (for example, “video distribution” or “high quality video distribution”) for each flow of information received by the reception unit 210, and the number of flows of the determined information type The reception speed of the flow per transmission destination is calculated by multiplying the bandwidth corresponding to the information type of the flow. The communication speed determination unit 230 determines whether the reception speed exceeds the transmission speed by comparing the calculated reception speed with the transmission speed measured by the bandwidth monitor 280.

  In this embodiment, the communication speed determination unit 230 compares the reception speed and the transmission speed, and the flow control unit 240 performs the flow control process according to the comparison result. Accordingly, since the priority control unit 250 can apply the same function as the conventional one, it is not necessary to modify the function of the priority control unit 250 in order to perform the communication control process according to the present embodiment, while utilizing the existing priority control function. The addition of functions according to this embodiment can be easily performed. The existing priority control function may be modified, and the modified priority control unit 250 may compare the reception speed with the transmission speed and provide a function unit that performs flow control processing according to the comparison result.

  In the present embodiment, the VDSL aggregation device 200 has been described as including a functional unit that controls the flow to be transmitted to the communication line on the reception side according to the comparison result between the reception speed and the transmission speed. 320 may be provided with a function unit for controlling the flow so that the flow transmitted to the terminal device 300 by the VDSL modem 320 may be controlled.

  In the present embodiment, the station apparatus 100 installed on the station side is described as the information transmitting side, and the terminal apparatus 300 installed in the house is described as the information receiving side. However, the terminal apparatus 300 installed in the house is described. The same communication control can be performed when the information transmission side is used and the station apparatus 100 installed on the station side is the information reception side. In this case, if the VDSL aggregation device 200 determines to stop transmission of information associated with a specific flow, the VDSL modem 320 transmits a packet stop command to the VDSL modem 320, and the VDSL modem 320 that has received the stop command Stop sending information by the corresponding flow.

  As described above, according to the present embodiment, when the communication speed of the communication line changes due to the SOS or SRA function, the flow control for each flow is executed in the type information corresponding to the same priority class. can do. For example, when information of two flows is transmitted to a user's terminal device in a video distribution service or the like, even if the communication speed decreases and a bandwidth for transmitting information of two flows cannot be secured, one flow or more If the bandwidth is secured, it is possible to transmit information by one of the two flows without lowering the communication quality. This can be expected to improve the service satisfaction level of the user.

  Note that a program for realizing the function of the processing unit in the present invention is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed to perform communication control. May be. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer system” includes a WWW system having a homepage providing environment (or display environment). The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

DESCRIPTION OF SYMBOLS 1 Communication system 10 Switching office 20 Apartment house 100 Station side apparatus 110 Exchange machine 200 VDSL aggregation apparatus 210 Reception part 220 Reception speed calculation part 230 Communication speed judgment part 240 Flow control part 250 Priority control part 260 Communication control part 261 SNR measurement part 262 SRA Control unit 263 SOS control unit 280 Bandwidth monitor 270 Transmission unit 290 Flow communication speed storage unit 300 Terminal device 310 Home communication device 320 VDSL modem 410 MDF
420 Optical Access Device

Claims (3)

A communication control device that transmits information transmitted from a transmission-side device connected via a transmission-side communication line to a reception-side device that is a destination of the information connected via a reception-side communication line. ,
A receiving unit for receiving a plurality of flows of the information transmitted from the transmitting side device;
A receiving speed calculating unit that calculates a receiving speed at which the receiving unit receives the information;
A transmission unit for transmitting the flow of information received by the reception unit to the reception-side device;
A transmission rate calculation unit for calculating a transmission rate at which the transmission unit transmits the information;
A communication speed determination unit for determining whether the reception speed calculated by the reception speed calculation unit exceeds the transmission speed calculated by the transmission speed calculation unit;
When the communication speed determination unit determines that the reception speed exceeds the transmission speed, the predetermined flow is determined as a flow to be stopped among the plurality of flows received by the reception unit, and is stopped. A flow control unit;
Priority control for the information corresponding to the flow other than the flow determined as the stop target by the flow control unit among the plurality of flows installed after the flow control unit and received by the reception unit A priority control unit for performing
In accordance with priority control by the priority control unit, a communication control unit that causes the transmission unit to transmit the information corresponding to a flow other than the flow determined as the stop target, and
A communication control apparatus comprising: A flow communication speed storage unit for storing an information type indicating a type of information transmitted from the transmission side apparatus and a flow communication speed indicating a communication speed of the flow corresponding to the information of the information type in association with each other; Prepared,
The reception speed calculation unit reads the flow communication speed associated with the information type of the flow received by the reception unit from the flow communication speed storage unit, and reads the information for each information type of the plurality of flows. The communication control apparatus according to claim 1, wherein the reception speed is calculated based on a flow communication speed. Communication control of a communication control apparatus that transmits information transmitted from a transmission side apparatus connected via a communication line on the transmission side to a reception side apparatus that is a destination of the information connected via a communication line on the reception side A method,
Receiving a plurality of flows of the information transmitted from the transmitting device;
A reception speed calculation unit calculating a reception speed at which the information is received by the reception unit;
A transmitting unit transmitting the flow of information received by the receiving unit to the receiving device;
Transmission rate calculating section, and a step of calculating a transmission rate at which the information I by the transmission section is transmitted,
A communication speed determination unit determining whether the reception speed calculated by the reception speed calculation unit exceeds the transmission speed calculated by the transmission speed calculation unit;
When the communication speed determination unit determines that the reception speed exceeds the transmission speed, the flow control unit determines a predetermined flow among the plurality of flows received by the reception unit as a flow to be stopped. Determining and stopping; and
The priority control unit installed after the flow control unit corresponds to a flow other than the flow determined as a stop target by the flow control unit among the plurality of flows received by the reception unit. Performing priority control on information;
A step of causing the transmission unit to transmit the information corresponding to a flow other than the flow determined as the stop target according to priority control by the priority control unit;
A communication control method comprising:

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