JP4259859B2 - Communication control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a communication control apparatus, and more particularly to a communication control apparatus that returns a response signal to a communication terminal when a received signal from the communication terminal satisfies a condition, for example.
[0002]
[Prior art]
Conventionally, when a data server sends data to a terminal device via a communication line, in order to control the data transfer amount (communication bandwidth) per unit time, the communication bandwidth that can be used for the terminal device is registered and transmitted autonomously. The amount of data to be adjusted was adjusted. In addition, a usable communication band for each terminal device is registered and adjusted in a packet switching device such as a router interposed in a communication line connecting the data server and the terminal device.
[0003]
[Problems to be solved by the invention]
However, for example, in a system in which one server is connected to a plurality of terminal devices, when the communication band (usable communication band) that can be used in each terminal device changes dynamically, the use of each terminal device It is necessary to dynamically set the possible communication bands individually. That is, each communication terminal or packet switching apparatus sets the usable communication band in accordance with a change in the actual usable communication band. In this case, since each communication terminal or packet switching apparatus is set independently, it is impossible to cope with a change in communication band that affects the entire system.
[0004]
As another control method, in order to cope with a change in the communication band that affects the entire system, a method of uniformly managing the usable communication band for each terminal device by the server can be considered. In this method, the available communication bandwidth for each terminal device managed by the server is notified to the terminal device as necessary, and the terminal device sets the notified available communication bandwidth in the device. However, with this method, there is a time lag from when the actual usable communication band changes until the setting of the usable communication band of the terminal device is changed, or the usable communication band value between the server and the terminal device. There is a disadvantage that a communication device for performing the above communication is required and the network control unit is complicated.
[0005]
Therefore, a main object of the present invention is to provide a communication control apparatus capable of dynamically and simply controlling the data transfer amount per unit time.
[0006]
[Means for Solving the Problems]
According to the present invention, the communication control device that returns a permission signal permitting transmission of the next signal to the communication terminal when a signal satisfying the condition is received from the communication terminal is detected by the first detection for detecting the target communication speed of the communication terminal. Means, second detection means for detecting the actual communication speed of the communication terminal, and return means for returning the permission signal at a timing based on the target communication speed and the actual communication speed.
[0007]
[Action]
In the communication control device that returns a permission signal permitting transmission of the next signal to the communication terminal when a signal satisfying the condition is received from the communication terminal, the first detection means detects a target communication speed of the communication terminal. The second detection means detects the actual communication speed of the communication terminal. The return means returns the permission signal at a timing based on the target communication speed and the actual communication speed.
[0008]
In a preferred aspect, the detection means detects the actual communication speed based on the difference between the previous reception timing and the current reception timing.
[0009]
Moreover, in another preferable aspect, the return means includes a first signal return means that promptly returns a permission signal when the actual communication speed is equal to or lower than the target communication speed.
[0010]
In another preferred aspect, the information processing apparatus further includes a calculation unit that calculates a delay time related to a difference between the actual communication speed and the target communication speed, and the return unit has a delay period when the actual communication speed is higher than the target communication speed. The second signal returning means for returning the permission signal after the elapse of time.
[0011]
【The invention's effect】
According to the present invention, the data transfer from the communication terminal can be appropriately delayed by transmitting a response signal at a timing based on the determination result of the determination means with respect to the reception signal from the communication terminal. The communication speed of the transmitted signal can be easily limited to a desired communication speed.
[0012]
The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.
[0013]
【Example】
Referring to FIG. 1, a remote monitoring system 10 of this embodiment includes an image storage server 12 having a storage capacity capable of storing a large amount of images. The image storage server 12 is connected to a plurality of camera devices 16, 16,.
[0014]
The internal configuration of the image storage server 12 is shown in FIG. In addition to the image data sent from the camera device 16, the internal memory 102 stores a program 110 executed by the CPU 106 and a communication bandwidth limit table 112. The HDD 104 stores a communication band limit setting table 114 in which values are input by an operator. The HDD 104 stores a large amount of image data sent from the camera device 16. The CPU 106 executes a program to support a protocol corresponding to the camera device 16 and receive image data sent from the camera device 16. Communication with the outside is performed via the network I / F 108.
[0015]
Each camera device 16 is configured as shown in FIG. The subject is photographed by the image sensor 202 and the photographed image data is temporarily stored in the internal memory 210. The flash memory 204 records a program 212 executed by the CPU 208. The CPU 208 executes the program 212 recorded in the flash memory 204 and transmits image data taken by the program to the image storage server 12. Communication with the outside is performed via the network I / F 206.
[0016]
An example of the items of the communication bandwidth limitation table 112 and the values of the respective items are shown in FIG. The communication bandwidth limit table 112 has items of all camera devices 16 connected to the image storage server 12 via a network. The items possessed by each camera device 16 are “maximum reception allowable data amount per second” and “fixed flag”. There are two values for the “maximum allowable reception data amount per second”, that is, the case where it is obtained by referring to the communication band limit setting table 114 and the case where it is calculated from the connection status of the camera device. More specifically, how the value of “maximum allowable reception data amount per second” is determined will be the setting value set by the operator in the communication band limit setting table 114 for the camera device 16. In this case, the set value is set to the value of “maximum reception allowable data amount per second” of the camera device 16 in the communication band limitation table 112. On the other hand, if there is no setting value set by the operator in the communication band limit setting table 114 for the camera device 16, the “maximum reception permissible data per second” is averaged between the camera devices having no setting value by the operator. The value of “amount” is calculated. The “fixed flag” is “1” (true) when the value of “maximum permissible reception data per second” is referred to from the communication bandwidth limit setting table 114, and “0” (false) otherwise. . Therefore, by referring to the “fixed flag”, it can be determined whether or not the value of “maximum reception allowable data amount per second” is designated by the operator.
[0017]
An example of the items of the communication bandwidth limit setting table 114 and the values of the respective items are shown in FIG. The communication bandwidth limit setting table 114 includes an item of the camera device 16 for which an operator has instructed a setting and an item of “total communication capacity” that allows communication via a communication line. For each item, a “maximum reception allowable data amount per second” can be set, and this value is input by the operator. Note that the communication speed is not limited for a camera device in which the setting value of “maximum reception capacity data amount per second” is set to “0”.
[0018]
The CPU 106 of the image storage server 12 executes the process shown in FIG. 7 according to the program 110 stored in the internal memory 102. First, an application processed by the image storage server 12 is executed in step S101. Next, in step S103, it is determined whether or not there is a data reception request from the camera device 16. If YES, step S113 and subsequent steps are executed, and if NO, step S105 and subsequent steps are executed.
[0019]
In step S113, the communication band restriction table 112 is referred to, and in the next step S115, it is determined whether or not the item of the camera device 16 that issued the data reception request is in the communication band restriction table 112. If there is an item, the process proceeds to step S125 to start the data reception processing handler. If there is no item, the process proceeds to step S117, and the communication band limit setting table 114 is referred to. In the next step S119, the item of the camera device 16 that has issued the reception request is added to the communication bandwidth limitation table 112. As for the contents of the added item, if there is a setting value referred to in step S117, the value is set in “maximum received data per second amount” and the fixed flag is set to “1”. If there is no set value referred to in step S117, the “maximum received data allowable amount per second” is left blank and the fixed flag is set to “0”.
[0020]
In step S121, the value is calculated so that the values of “maximum received data allowance per second” of the camera device 16 whose fixed flag is “0” are averaged. The value is calculated by a function of the total communication capacity, the set value of the camera device whose fixed flag is “1”, and the number of camera devices whose fixed flag is “0”. In the next step S123, the communication band restriction table 112 is updated based on the result calculated in step S121.
[0021]
When the update of the communication bandwidth limitation table 112 is completed, the process proceeds to step S125, and the “data reception processing handler” is activated. Details of the “data reception processing handler” will be described later. When the activation of the “data reception processing handler” is completed, the process returns to step S101 to perform normal application processing.
[0022]
When there is no reception request from the camera device 16 in step S103, first, in step S105, it is checked whether the camera device 16 in the communication bandwidth restriction table 112 is connected to the network. If there is a disconnected camera device 16 in the next step S107, the disconnected camera device 16 is deleted from the communication bandwidth restriction table 112 in step S109, and the communication bandwidth restriction table 112 is deleted in the next step S111. Update the value. The value updating method is performed in the same manner as in step 123 above.
[0023]
When the update of the communication bandwidth limitation table 112 is completed, the process proceeds to step S127, and it is determined whether or not a power-off command is input to the image storage server 12. If the image storage server 12 has a power-off command, the image storage server 12 turns off the power after the end process. If the image storage server 12 does not receive a power-off command, the process returns to step S101 and application processing of the image storage server 12 is performed.
[0024]
The data reception processing handler in step S125 of FIG. 7 is executed according to the flow shown in FIGS. First, in step S131, the communication bandwidth limit table 112 is referred to obtain the “maximum received data allowable amount per second” corresponding to the camera device 16 that has requested data reception and substitute it into the variable “MAX”. When the assignment to “MAX” is completed, the process proceeds to step S133, and it is determined whether or not there is a communication bandwidth limitation for the camera apparatus that has requested data reception. Whether there is a communication bandwidth limit is determined from the value of “MAX” obtained by referring to step S131. When the value of “MAX” is positive, there is a communication band limitation. When the value of “MAX” is “0” or a negative value, there is no communication band limitation. If it is determined in step S133 that there is a communication bandwidth limitation, steps S135 to S143 are executed. If it is determined in step S133 that there is no communication band limitation, the process proceeds to step S145.
[0025]
Steps S <b> 135 to S <b> 143 are preprocessing when there is a communication band limitation. In step S135, the measurement unit time (S) is calculated. The measurement unit time is a function with “MAX” as a parameter. Next, a basic packet interval time (T) is calculated in step S137. The basic packet interval time is a function with “MAX” as a parameter. In step S139, “0” is substituted for the received data amount (D) within the unit time. When the substitution is completed, the packet interval measurement timer (p) and the measurement unit time timer (s) are reset in steps S141 and S143, and each timer is started from "0". When the resetting of the timer is completed, the process proceeds to step S145.
[0026]
In step S145, a packet from the camera device is received. At this time, the size of the packet is “d”. When the packet reception is completed, it is determined in step S147 whether or not there is a communication band limitation. If there is a communication band limitation, the process proceeds to step S149, and if there is no communication band limitation, the process proceeds to step S171. Whether or not there is a communication bandwidth limit is determined by the value of “MAX” as in step S133.
[0027]
In step S149, the received data amount (D) within the unit time is updated by adding the size of the packet received in step S145. When the update of “D” is completed, the process proceeds to step S151, and it is determined whether the measurement unit time timer (s) exceeds the measurement unit time (S). If the measurement unit time timer (s) exceeds the measurement unit time (S), the packet interval measurement timer (p), the received data amount (D) within the unit time, and the unit time measurement timer are determined in steps S153 to S157. (S) is reset, and the process proceeds to step S171 to immediately return “ACK” (acknowledgement) or “NAK” (negative acknowledgment). On the other hand, if the measurement unit time timer (s) does not exceed the measurement unit time (S) in step S151, the process proceeds to step S159.
[0028]
In step S159, it is determined whether the packet interval measurement timer (p) has exceeded the basic packet interval time. If the packet interval measurement timer (p) exceeds the basic packet interval time, the packet interval measurement timer is reset in step S161, and the process proceeds to step S171 to immediately return “ACK” or “NAK”. If the packet interval measurement timer (p) does not exceed the basic packet interval time, step S163 and the subsequent steps are executed. In step S163, a delay time (t) is calculated. The delay time (t) is the received data amount (D), the packet size (d), the packet interval measurement timer value (p), the measurement unit time (S), the measurement unit time timer value (s), and the unit time. This is a function having the basic packet interval time (T) as a parameter. When the calculation of the delay time (t) is completed, the packet interval measurement timer is reset in step S165, and the delay time (t) is waited for in step S167. When waiting for the delay time (t) ends, it is determined in step S169 whether the measurement unit time timer (s) has exceeded the measurement unit time (S). If the measurement unit time timer (s) exceeds the measurement unit time (S), after resetting the received data amount (D) and the unit time measurement timer (s) within the unit time in steps S155 to S157, The process proceeds to step S171. On the other hand, if the measurement unit time timer (s) does not exceed the measurement unit time (S) in step S169, the process proceeds to step S171 as it is.
[0029]
In step S171, it is determined whether the packet data received from the camera device is correct. Whether the packet data is correct is determined based on the validity of the packet included in the packet, the sequence number that guarantees the order, and the block check code such as a checksum or CRC. If the packet data is correct as a result of this determination, "ACK" is sent in step S173. Then, if it is determined in step S175 that the received data is ended by the end determination of the received data, the process returns to the main process. On the other hand, if it is determined that the received data has not ended yet, the process proceeds to step S145 to receive the next packet.
[0030]
On the other hand, if it is determined in step S171 that the received packet is not correct, the process proceeds to step S177. If retry is to be performed, “NAK” is transmitted and the process proceeds to step S145. If there is no retry, error processing is performed in step S181. After that, the process returns to the main process. Whether or not to retry in step S177 is determined based on whether or not the number of retries for the same packet has reached a specified number.
[0031]
FIG. 4 is an illustrative view showing timings of a measurement unit time (S), a basic packet interval time (T), a packet interval time (p), and a delay time (t) when the data reception processing handler is executed by the CPU 106. Shown in
[0032]
FIG. 4A is an illustrative view when packets are received at the same interval as the basic packet interval time (T). In this case, since the maximum permissible reception data amount (communication bandwidth limitation) per second matches the actual data communication speed, the delay time (t) for returning “ACK” does not occur.
[0033]
FIG. 4B is an illustrative view when the packet reception interval is shorter than the basic packet interval time (T), that is, when the packet arrives at a communication speed faster than the communication bandwidth limit. Since the packet B arrived in a time shorter than the basic packet interval time (T) (timing in FIG. 4A), an appropriate delay time (t) so that the packet C arrives at the timing in FIG. "ACK" is returned after. Since the packet C arrived at a timing earlier than that in FIG. 4A, a longer delay time than that in the case of the packet B is given, and “ACK” is received so that the packet D arrives at the timing in FIG. It is returning.
[0034]
FIG. 4C is an illustrative view when reception of the packet B is delayed. The packet B is received much later than the timing of FIG. 4A, that is, it is received after a time much longer than the basic packet interval time since the packet A was received. Since the interval time between the packet A and the packet B is longer than the basic packet interval time, “ACK” for the reception of the packet B is immediately returned. Since the packet C is received at a timing shorter than the basic packet interval time from the packet B, “ACK” is received after an appropriate delay time (t) so that the next packet D arrives at the timing of FIG. It is returning. Next, the received packet D has a small amount of received data within the measurement unit time until the packet D is received, and arrives at a timing later than the timing of the packet D in FIG. Although the packet interval time is shorter than the basic packet interval time (T), “ACK” is returned without delay time.
[0035]
The CPU 208 of the camera device 16 performs the process shown in FIG. 10 according to the program 212 stored in the flash memory. First, in step S201, an application processed by the camera device is executed. Next, when there is a data transmission request by the application operating in step S203, the process proceeds to step S207 to activate the data transmission processing handler. Details of the data transmission processing handler will be described later. If there is no data transmission request from the running application in step S203, the process proceeds to step S205. If there is no power-off command for the camera device in step S205, the process returns to step S201. When a power-off command is issued in step S205, the processing of the program 214 ends and the camera device is turned off.
[0036]
The data transmission processing handler in step S207 of FIG. 10 is executed according to the flow shown in FIG. First, in step S211, the data to be transmitted is divided into packets. Next, in step S213, it is determined whether there is a packet to be transmitted. If there is a packet to be transmitted, step S215 and the subsequent steps are executed. If there is no packet to be transmitted, the data transmission processing handler is terminated.
[0037]
In step S215, the packet is transmitted to the image storage server 12. In step S217, a response of “ACK” or “NAK” from the image storage server 12 is awaited. In the next step S219, it is determined whether or not the packet has been transmitted correctly. The determination method means that if the response obtained in step S217 is “ACK”, it means that the packet has been transmitted correctly, and returns to step S213 to transmit if there is a packet to be transmitted next. If the response obtained in step S217 is “NAK” or if there is no response and timed out, this means that the packet could not be transmitted correctly, and the process proceeds to step S221. In step S221, it is determined whether to retransmit the packet that failed to be transmitted. When retransmitting, the process returns to step S215 to transmit the failed packet again. When not transmitting again, it moves to step S223, performs error processing, and returns to the main processing.
[0038]
The packet transmission of the camera device 16 is processed in the same procedure as the packet transmission generally performed. Therefore, the present invention is realized by changing the procedure only on the reception side, and the transmission side may be a general data transmission device.
[0039]
As can be understood from the above description, the communication speed of each data transmission terminal can be limited by appropriately delaying the “ACK” or “NAK” timing returned from the receiving side.
[0040]
The “total communication capacity” in the communication band limit setting table 114 is input by the operator, but it is also possible to use the value calculated from the result of measuring the actual communication capacity of the communication line.
[Brief description of the drawings]
FIG. 1 is an illustrative view showing one embodiment of the present invention;
FIG. 2 is a block diagram showing a part of the embodiment in FIG. 1;
FIG. 3 is a block diagram showing another part of the embodiment in FIG. 1;
4 is an illustrative view showing one portion of operation of FIG. 1 embodiment; FIG.
FIG. 5 is an illustrative view showing a part of FIG. 1 embodiment;
6 is an illustrative view showing still another portion of the embodiment in FIG. 1; FIG.
7 is a flowchart showing a part of the operation of FIG. 1 embodiment; FIG.
FIG. 8 is a flowchart showing still another part of the operation of the embodiment in FIG. 1;
FIG. 9 is a flowchart showing still another part of the operation of FIG. 1 embodiment;
FIG. 10 is a flowchart showing still another portion of the operation of the embodiment in FIG. 1;
FIG. 11 is a flowchart showing still another part of the operation of the embodiment in FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Communication system 12 ... Image storage server 16 ... Camera apparatus 20 ... Network

Claims (3)

In a communication control device that returns a permission signal permitting transmission of the next signal to the communication terminal when a signal satisfying a condition is received from one of a plurality of communication terminals connected to the network,
Target communication speed determining means for determining a target communication speed according to the connection status of the plurality of communication terminals;
E Bei a returning means for returning the authorization signal at the timing based on the communication speed detection means, and said target communication speed and the actual communication speed for detecting the actual communication speed of the communication terminal,
The communication control apparatus, wherein the target communication speed is an average value of each maximum received data allowable amount of the plurality of connected communication terminals . In a communication control device that returns a permission signal permitting transmission of the next signal to the communication terminal when a signal satisfying a condition is received from one of a plurality of communication terminals connected to the network,
Target communication speed determining means for determining a target communication speed according to the connection status of the plurality of communication terminals;
E Bei a returning means for returning the authorization signal at the timing based on the communication speed detection means, and said target communication speed and the actual communication speed for detecting the actual communication speed of the communication terminal,
Communication bandwidth restriction setting means for setting a communication bandwidth restriction for the communication terminal;
When the communication band limit is set by the communication band control setting unit, the target communication speed is set as a set value, and when the communication band limit is not set by the communication band limit setting unit, the target communication speed is set. A communication control apparatus characterized in that an average value of each maximum received data allowable amount of a communication terminal for which no communication band restriction is set is set among the plurality of communication terminals . A calculation means for calculating a delay time related to a difference between the actual communication speed and the target communication speed;
3. The return means according to claim 1 , wherein the return means includes second signal return means for returning the permission signal after the delay period has elapsed when the actual communication speed is higher than the target communication speed. Communication control device.

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