JP2000354065A - Communication controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a communication controller which can communicate communication data, even if the data have a low priority while securing the communications of high- priority communication data and can prevent reattempt of a low-priority communication sequence. SOLUTION: A communication controller is provided with a priority order deciding section 23, which rearranges communication data transmitted from a transmitting terminal 10 in a priority order of data reception, a congestion state detecting section 24 which detects and monitors the congestion states of a plurality of receiving terminals, and a packet abandoning section 25, which selects the communication data distributed to each receiving terminal 30 on the basis of the rearranged communication data and the detected degree of congestion states and abandons low-priority communication data. The controller is also provided with an abandoned packed information storing section 50, which stores the number of continuously abandoned times of abandoned low-priority communication data for every priority and a low-priority packet transmission deciding section 51, which replaces the priority of low-priority communication data with high-priority communication data, on the basis of the number of continuously abandoned times stored in the section 50 and gives the low-priority communication data to the section 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control device for distributing communication data having a plurality of priorities.

[0002]

2. Description of the Related Art As a conventional communication control device, for example, as disclosed in Japanese Patent Laid-Open No. Hei 10-247944, a congestion state for each communication partner is detected, and communication data having a low priority is discarded according to the state. Thus, the relay control device improves the congestion state while distributing communication data with high priority.

FIG. 14 is a block diagram showing a configuration of a communication control device disclosed in Japanese Patent Laid-Open No. Hei 10-247944. The communication control device shown in FIG. 14 is divided into a transmission terminal 10, a relay control device 20, and reception terminals 30A, 30B, and 30C. The relay control device 20 is an I / O that connects to the transmission terminal 10 and the reception terminal 30. F21, 27, transmitting terminal 10
Communication data receiving unit 22 for receiving data from a plurality of communication data, priority order determining unit 23 for determining the priority of a plurality of communication data, congestion state detecting unit 2 for managing the congestion state of each receiving terminal 30
4. A packet discarding unit 25 for discarding communication data that is not distributed due to the congestion state of each receiving terminal 30, and a distribution unit 26 for sending communication data to the transmission path via the I / F 27.

Next, the operation of the above configuration will be described with reference to FIG. 15, which describes the priority of communication data.
The communication data transmitted from the transmitting terminal 10 is transmitted to the I / F 21
Via the communication data receiving unit 2
2 to receive. The received communication data has an identification number (priority) indicating its importance, and is divided into 1 to 5 as shown in FIG. 15, and the lower the number, the higher the priority. I have. For convenience of explanation, the following operation will be described on the assumption that five communication data 40 have been transmitted from the transmission terminal 10 as shown in FIG.

[0005] The priority order determining unit 23 sorts the communication data received by the communication data receiving unit 22 in the order of priority seats.
In addition, the congestion state detection unit 24 constantly monitors the congestion state of each receiving terminal 30. The packet discarding unit 25 and the distribution unit 26 distribute the communication data 40 rearranged by the priority determination unit 23 and the congestion state of the receiving terminal 30 managed by the congestion state detection unit 24 according to the degree of the congestion state. Communication data to be distributed is selected and distributed to the receiving terminal 30 via the I / F 27, and data not distributed is discarded.

For example, if congestion does not occur in the receiving terminal 30A, some congestion occurs in the receiving terminal 30B, and serious congestion occurs in the receiving terminal 30C, the packet discarding unit 25 and the distribution unit 26 is the receiving terminal 3
All the communication data 41 transmitted from the transmitting terminal 10 are distributed to 0A, but the communication data 42 obtained by discarding the packet 5 having the lowest priority is distributed to the receiving terminal 30B. Then, to the receiving terminal 30C, the data of the first to third levels with low priority is discarded, and only the communication data 43 with high priority is distributed.

The communication control apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 10-247944 only discards low-priority packets in a congested state.
As shown in (1), the retransmission request processing unit 28 receives the discard information from the packet discarding unit 25, performs processing for retransmitting the discarded packet, and the retransmission request requesting unit 29 sends a request for retransmission via the I / F 21. Then, by transmitting the low-priority communication data discarded by the transmitting terminal 10 to the transmitting terminal 10 again, a means for improving the reliability of the communication is taken.

[0008]

Since the conventional communication control device is configured as described above, if the congestion state continues, the low-priority communication stops at all. It was necessary to create an algorithm that takes into account the lack of communication data over time. In addition, due to the low priority, a packet for performing communication control and the like are also discarded, causing a problem that a communication sequence is wasted and a communication frequency is further increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and enables communication of low-priority communication data under certain conditions while securing high-priority communication. It is an object of the present invention to obtain a communication control device capable of preventing the re-transmission of the communication sequence of the first communication from occurring.

[0010]

A communication control apparatus according to the present invention receives a communication data transmitted from a transmitting terminal and sorts the data in order of priority, and detects a congestion state of a plurality of receiving terminals. A congestion state detection unit to be monitored, and communication data to be distributed to each receiving terminal based on the communication data rearranged by the priority order determination unit and the degree of the congestion state detected by the congestion state detection unit. A communication data discarding unit for discarding communication data of a different degree; a discard information storage unit for storing, for each priority, the number of continuous discards of low-priority communication data discarded by said communication data discarding unit; Provided between the priority determining unit and the communication data discarding unit, and based on the number of continuous discards stored in the discard information storage unit, The replaced with high-priority communication data is characterized in that a low-priority communication data transmission determining section that gives to the communication data discard unit.

A priority determining unit for receiving communication data transmitted from the transmitting terminal and rearranging the data in order of priority; a congestion state detecting unit for detecting and monitoring congestion states of a plurality of receiving terminals; A communication data discarding unit that sorts communication data distributed to each receiving terminal based on the degree of the congestion state detected by the congestion state detection unit and the communication data sorted by the communication data and discards low-priority communication data. A communication control device comprising: a control packet instructing unit for instructing a type of a control packet to be delivered as communication data; and a low priority provided between said priority order determining unit and said communication data discarding unit for discarding. When the communication data of the communication control packet indicated by the control packet instructing unit is included in the communication data, the priority of the communication control packet is set to the distribution schedule. Of the communication data, the most priority is low, and is characterized in that a control packet transmission decision unit for outputting a delivery instruction to replace the communication data is not a communication control packet.

A priority determining unit for receiving communication data transmitted from the transmitting terminal and rearranging the data in order of priority; a congestion state detecting unit for detecting and monitoring congestion states of a plurality of receiving terminals; A communication data discarding unit that sorts communication data distributed to each receiving terminal based on the degree of the congestion state detected by the congestion state detection unit and the communication data sorted by the communication data and discards low-priority communication data. In the communication control device provided, the size of the communication data rearranged by the above-mentioned priority order determination unit is checked, and the high-priority communication data to be delivered is smaller than a communicable packet size that does not affect the congestion state. First, a search is made for low-priority communication data that fits in the vacant area. It is characterized in further comprising a generation unit.

A priority determining unit that receives communication data transmitted from the transmitting terminal and sorts the data in order of priority; a congestion state detecting unit that detects and monitors congestion states of a plurality of receiving terminals; A communication data discarding unit that selects communication data to be distributed to each receiving terminal based on the degree of the congestion state detected by the congestion state detection unit and the communication data that is rearranged, and discards low-priority communication data, A retransmission request processing unit for performing a retransmission request process for communication data discarded by the communication data discarding unit, and a retransmission request requesting unit for requesting the transmission terminal to retransmit the communication data processed by the retransmission request processing unit by the retransmission request processing unit In the communication control device having the above, provided between the retransmission request processing unit and the retransmission request requesting unit, and a retransmission request is issued by the retransmission request processing unit A retransmission number measurement unit that measures the number of retransmissions of one communication data, and a priority change that changes the priority of the communication data to a higher priority based on the number of retransmissions measured by the retransmission number measurement unit and sends the communication data to the retransmission request request unit. And a unit.

Further, the frequency of occurrence of communication data for each priority within a predetermined time is measured based on the output from the priority order determination section, and the frequency of occurrence of the measured communication data or the frequency of occurrence of the communication data is detected by the congestion state detection section. And a priority change stop instruction unit for stopping the priority change by the priority change unit based on the congestion state of the receiving terminal.

A priority determining unit for receiving communication data transmitted from the transmitting terminal and rearranging the data in order of priority;
A congestion state detection unit that detects and monitors the congestion state of a plurality of reception terminals, and to each reception terminal based on the communication data rearranged by the priority order determination unit and the degree of the congestion state detected by the congestion state detection unit. In a communication control device including a communication data discarding unit for selecting communication data to be distributed and discarding low-priority communication data, a non-communication time of the low-priority communication data discarded by the communication data discarding unit is measured. A non-communication time measuring unit that is provided between the priority order determining unit and the communication data discarding unit, based on the non-communication time measured by the non-communication time measuring unit. A low-priority communication data transmission determining unit that replaces the priority with high-priority communication data and provides the communication data discarding unit with the low-priority communication data.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a communication control device according to Embodiment 1 of the present invention. In FIG. 1, the same parts as those of the conventional example shown in FIG. As a new code, 50 is a discarded packet information storage unit that records information of packets discarded for each priority, and 51 is a case where packet discarding continues based on the information. Is a low-priority packet transmission determining unit that replaces high-priority communication data to be distributed.

Next, the operation will be described with reference to the explanatory diagram of the priority of communication data shown in FIG. 2 and the table of the discarded packet information storage unit 50 shown in FIG. The communication data transmitted from the transmitting terminal 10 reaches the relay control device 20 via the I / F 21 and is received by the communication data receiving unit 22. The received communication data has an identification number (priority) indicating its importance. For example, as shown in FIG. 2, the communication data is divided into 1 to 5 stages, and the lower the number, the higher the priority. Has become. For convenience of explanation, the following operation will be described on the assumption that five communication data 40 have been transmitted from the transmitting terminal 10 as shown in FIG.

The priority order determining unit 23 sorts the communication data received by the communication data receiving unit 22 in order of priority. In addition, the congestion state detection unit 24 constantly monitors the congestion state of each receiving terminal 30. The communication data 40 rearranged in the priority order by the priority order determination unit 23 and the low-priority packet transmission determination unit 51 and the congestion state of the reception terminal 30 managed by the congestion state detection unit 24 determine the congestion state. Communication data to be distributed is selected according to the degree and distributed to the receiving terminal 30 via the distribution unit 26 and the I / F 27. Data not to be distributed is discarded by the packet discarding unit 25. Up to this point, it is the same as the conventional example.

When there is a discarded packet, the discarded packet information storage unit 50 adds the discard number to the continuous discard number 100 of the corresponding priority in the table as shown in FIG.
At this time, if it can be delivered even once, the number of continuous discards is 10
0 is returned to 0, and the current priority 101 is also the basic priority 103
Return to The low-priority packet transmission determining unit 51 raises the priority of the low-priority communication data based on the table of FIG. 3 according to the algorithm shown in FIG.

Now, an algorithm for increasing the priority will be described by taking priority 5 as an example. The low-priority packet transmission determining unit 51 determines the S based on the value 5 of the current priority 101 of the communication data whose basic priority 103 is 5 in the table of FIG.
In the TEP 11, the set value of the number of consecutive discards for increasing the priority is calculated from the priority increase set value 102. In the case of FIG. 3, the calculation set value is 16. If the basic priority 103
When the current priority 101 of the communication data of “5” is 4, the priority increase setting values 10 of 5 and 4 of the basic priority 103 are set.
24, which is the total value of 2, is the calculation set value.

Next, in STEP 12, the current continuous discard number 100 is compared with the calculated set value, and the continuous discard number 10 is determined.
If 0 exceeds the calculation set value, the communication data of the priority determined by the priority determination unit 23 in STEP 13 is replaced with communication data having a priority one higher than the own priority. Thus, depending on the congestion state, the distribution data 52 in FIG.
As shown in, the data of the priority 5 is delivered to the receiving terminal 30B instead of the data of the priority 4. However, in a terminal having a very bad congestion state, such as the receiving terminal 30C, there is a possibility that the data may not be delivered if the priority is increased by one step.
Increase 01 by one.

As described above, according to the first embodiment, when low-priority communication data is discarded, the discarded packet information storage unit 50 counts the discarded packet and continuously discards the packet. In this case, the low-priority packet transmission determining unit 51 replaces the high-priority communication data with the distributed high-priority communication data. Communication can be performed, the non-communication state can be avoided, and there is an effect of preventing loss of communication data for a long time.

Embodiment 2 FIG. In the first embodiment, the low-priority packet transmission determining unit 51 replaces the priority so that low-priority communication data can be distributed. When the low-priority communication data to be discarded is a communication control packet instead of the priority packet transmission determination unit 51, a control packet transmission determination unit 61 that replaces the high-priority communication data to be distributed, and a communication control packet that replaces An embodiment will be described in which a control packet instructing unit 60 for designating is specified.

FIG. 5 is a block diagram showing a configuration of a communication control device according to the second embodiment of the present invention. 5, the same parts as those of the conventional example shown in FIG. 14 are denoted by the same reference numerals, and the description thereof will be omitted. As a new code, reference numeral 60 denotes a control packet indicating unit for indicating the type of control packet, and reference numeral 61 denotes a case where the content of the packet is a packet for which communication control is performed even in a low priority packet based on the instruction from the control packet indicating unit 60. Is a control packet transmission determining unit that issues a distribution instruction as in the case of the high priority.

Next, the operation of the communication control apparatus according to the second embodiment will be described. The operation of the part for rearranging the communication data transmitted from the transmission terminal 10 by priority and the operation of the part for distributing the communication data to the reception terminal 30 or discarding the low-priority packet according to the congestion state are the same as those of the conventional example. It is omitted because it is the same.

In the second embodiment, the control packet transmission determining unit 61 checks the contents of the communication data rearranged by the priority order determining unit 23, and
Of the connection request and the Ack (Acknowledg
e) When a communication control packet specified by the control packet instructing unit 60, such as a response or a Nac (Negative Acknowledge) response, is included, the priority of the control packet is set to one of the communication data to be distributed. Low priority,
Exchanges with communication data that is not a communication control packet. When there are a plurality of low-priority communication data to be discarded, and a plurality of communication control packets are included therein, the communication control packet having the highest priority among the discarded packets is subjected to the above processing.

As described above, according to the second embodiment, an attempt is made to distribute a communication control packet such as an Ack packet specified by the control packet instructing section 60 among the low-priority communication data. If there is, the control packet transmission determining unit 61 replaces the priority with the high-priority communication data to be distributed, so that useless re-communication (for example, because an Ack response could not be returned, This eliminates the need for re-communication), thereby reducing the total amount of communication, and has the effect of enabling the communication state to be communicated to the communication partner earlier even in low-priority communication.

Embodiment 3 In the first embodiment, the low-priority packet transmission determining unit 51 replaces the priority so that low-priority communication data can be distributed. If the distribution area of the high-priority communication packet to be distributed has a margin (empty area) for the size of the low-priority communication packet to be discarded instead of the low-priority packet transmission determination unit 51, An embodiment will be described in which a high / low packet combining unit 70 for combining communication data is added.

In the case of packet communication, for example, LAN (I
EEE802.3: The Institute of Electrical and E
electronics Engineers; 8 from the American Electrical and Electronics Engineers Association
There is a packet size that does not affect congestion, such as a minimum packet size of 60 bytes (maximum of 1514 bytes) of the standard established by the 02 Committee. In the third embodiment, if the high-priority communication data is to be delivered without using up the packet size that does not affect the congestion state, the low-priority communication data will not exceed the data size of this free area. When there is such data, the purpose is to distribute the low-priority communication data by embedding and distributing the low-priority data in the high-priority communication data.

FIG. 6 is a block diagram showing a configuration of a communication control device according to Embodiment 3 of the present invention. 6, the same parts as those of the conventional example shown in FIG. 14 are denoted by the same reference numerals, and description thereof will be omitted. As a new code, 70 is provided between the priority determining unit 23 and the packet discarding unit 25, and checks the size of the communication data rearranged by the priority determining unit 23 and distributes it. If the communication data is smaller than the communicable packet size that does not affect the congestion state, the communication device searches for low-priority communication data that fits in the empty area, and if there is, combines a plurality of communication data and sets It is a high / low packet combining unit that uses priority communication data.

Next, the operation of the communication control apparatus according to the third embodiment will be described with reference to the communication data synthesizing diagram shown in FIG. The operation of the part for rearranging the communication data transmitted from the transmission terminal 10 by priority and the operation of the part for distributing the communication data to the reception terminal 30 or discarding the low-priority packet according to the congestion state are the same as those of the conventional example. It is omitted because it is the same.

In the third embodiment, the high / low packet combining section 70 checks the size of the communication data rearranged by the priority determination section 23, and the high-priority communication data to be distributed affects the congestion state. If the packet size is equal to or less than the communicable packet size without any, there is searched for low-priority communication data that fits in the empty area, and if there is, a plurality of communication data are synthesized and distributed as high-priority communication data.

For example, as shown in FIG. 7, even if priority 1 communication data 110 and priority 5 communication data 114 are combined,
If the transmittable packet size is not exceeded, the communication data of the two priorities is replaced with the new communication data of the priority 1
5 is delivered. Naturally, the receiving side has a procedure for performing the division processing.

As described above, according to the third embodiment, there is high-priority communication data less than the maximum packet size, and at the same time, among low-priority communication data to be discarded, If there is communication data of a size that fits in the empty area of the packet of the high-priority communication data to be distributed, the high-low packet combining unit 70 can collectively distribute the communication data into one high-priority communication data. It is possible to avoid the non-communication state of low-priority communication data and distribute high-priority and low-priority communication data without affecting the congestion state. Has the effect of preventing.

Embodiment 4 FIG. The above-described first, second, and third embodiments provide low-priority communication even in a bad congestion state in communication in which packet discarding has occurred and there is no problem without retransmitting the discarded data. Although data could be distributed, in the fourth embodiment,
An object of the present invention is to improve the distribution rate of low-priority communication data in a communication control device that eliminates data loss by retransmitting the data when packet discarding occurs.

As described in the prior art, Japanese Patent Laid-Open No.
The communication control device disclosed in Japanese Patent No. 7944 discards a low-priority packet in a congested state. In a general communication control device, as shown in FIG. Upon receiving the discard information, the packet rejected by the retransmission request processing unit 28 is processed for retransmission, and the retransmission request requesting unit 29 sends a request for retransmission to the I / O
The transmission terminal 10 sends the communication data to the transmission terminal 10 via F21, and the transmission terminal 10 retransmits the discarded low-priority communication data.

Therefore, even in the communication control device that performs the retransmission process, there is a problem that the distribution of low-priority communication data is stagnated. Therefore, in a fourth embodiment, a description will be given of an embodiment in which a retransmission number measurement unit 80 that counts the number of retransmissions and a priority change unit 81 that raises the priority according to the number of retransmissions are added to the configuration of the conventional example.

FIG. 8 is a block diagram showing a configuration of a communication control apparatus according to Embodiment 4 of the present invention. 8, the same components as those of the conventional example shown in FIG. 16 are denoted by the same reference numerals, and description thereof will be omitted. As a new code, reference numeral 80 denotes a retransmission number measuring unit that measures the number of retransmissions of the same communication data requested to be retransmitted by the retransmission request processing unit 28, and reference numeral 81 denotes a number based on the number of retransmissions measured by the retransmission number measuring unit 80. Change the priority of the communication data to a higher priority and request the retransmission request 2
9 is a priority changing unit to be sent to the control unit 9.

Next, the operation of the communication control apparatus according to the fourth embodiment will be described. Along with the operation of rearranging the communication data sent from the transmitting terminal 10 by priority and distributing the communication data to the receiving terminal 30 according to the congestion state, and the operation of discarding the low-priority packet,
A part for receiving the discard information and performing a process for retransmitting the packet discarded by the retransmission request processing unit 28. The retransmission request requesting unit 29 sends a request for the retransmission to the transmitting terminal 10 via the I / F 21. Since the retransmission by the transmitting terminal 10 is the same as in the conventional example, the description is omitted.

In the fourth embodiment, when the retransmission process starts,
The number of times the corresponding data is to be retransmitted,
In accordance with the original priority of the communication data and the number of retransmissions, the priority change unit 81 refers to a built-in table as shown in FIG. 9 to determine the setting priority at the next retransmission. Then, the packet is transmitted to the transmitting terminal 10 via the retransmission request requesting unit 29 and the I / F 21. The transmission terminal 10 includes a priority change unit 81
The communication data is retransmitted in accordance with the priority determined in (1). For example, the communication data with the original priority of 4
The priority when entering the fifth retransmission procedure is 3.

As described above, according to the fourth embodiment, in the communication control apparatus which performs retransmission processing when a packet is discarded, the priority change section 81 changes the priority in accordance with the number of retransmissions counted by the transmission number measuring section 80. By increasing the priority at the time of retransmission and retransmitting, the packet discard rate at the time of retransmission is reduced, and low-priority communication data can be distributed. Even with low-priority communication data, the priority increases each time the number of retransmissions increases Is high, and transmission can be performed at a fixed rate (time) even to the receiving terminal 30 in a bad congestion state, so that there is an effect of preventing loss of communication data for a long time.

Embodiment 5 FIG. In the fourth embodiment, a case has been described in which the priority of retransmission communication data is uniformly increased according to the number of retransmissions. In this case, communication data of higher priority due to retransmission, In the fifth embodiment, as shown in FIG. 10, a priority change stop instruction unit 82 that measures the frequency of occurrence of communication data and the congestion state for each priority within a certain time is added because it may cause discarding. An embodiment will be described.

FIG. 10 is a block diagram showing a configuration of a communication control device according to Embodiment 5 of the present invention. 10, the same parts as those of the fourth embodiment shown in FIG. 8 are denoted by the same reference numerals, and the description thereof will be omitted.
The reception terminal measures the frequency of occurrence of communication data for each priority within a certain time based on the output from the priority order determination unit 23, and detects the frequency of occurrence of the measured communication data or the reception terminal detected by the congestion state detection unit 24. Is a priority change stop instructing unit that stops the priority change by the priority change unit 81 based on the congestion state.

Next, the operation of the communication control apparatus according to the fifth embodiment will be described. Basically, the operation is the same as that of the fourth embodiment, except that the priority change stop instruction unit 82
FIG. 11 shows the frequency of occurrence of communication data for each priority within a certain time.
When the frequency of occurrence exceeds the basic occurrence frequency as shown in (1), the procedure for changing the priority to a higher priority than the corresponding priority in the priority changing unit 81 is stopped. In the congestion state detection unit 24,
When the congestion state of at least one receiving terminal 30 in the communication network becomes worse than a certain state, all the priority changes in the priority changing unit 81 are stopped.

As described above, according to the fifth embodiment, in the communication control apparatus according to the fourth embodiment, retransmission of low-priority communication data due to a change in priority impedes high-priority communication. Instead, the priority change stop instruction unit 82 checks the traffic and the congestion state for each priority so that a certain communication can be secured, and depending on the state, the priority change unit 81 performs retransmission at the time of retransmission. By not changing the priority, it is possible to distribute the low-priority communication data and not affect the high-priority communication, and when the amount of the high-priority communication data increases, When the congestion attack of the receiving terminal worsens, the function of raising the priority by retransmission stops, so that there is an effect that communication data of high priority does not stagnate.

Embodiment 6 FIG. In the first embodiment, the low-priority packet transmission determining unit 51 replaces the priority based on the number of discarded packets, so that low-priority communication data can be transmitted. In the sixth embodiment, a non-communication time measuring unit that measures a continuous non-communication time for each priority instead of the discarded packet information storage unit 50 in order to replace the priority based on the time during which communication is not possible. An embodiment for adding 120 will be described.

FIG. 12 is a block diagram showing a configuration of a communication control apparatus according to Embodiment 6 of the present invention. 12, the same parts as those of the conventional example shown in FIG. 14 are denoted by the same reference numerals, and the description thereof will be omitted. As a new code, 120
A non-communication time measuring unit that measures the non-communication time of the low-priority communication data discarded by the packet discard unit 25;
A low-priority communication data transmission unit 21 replaces the priority of the low-priority communication data with the high-priority communication data based on the non-communication time measured by the non-communication time measuring unit 120 and gives the priority to the packet discarding unit 25. The decision unit.

Next, the operation of the communication control apparatus according to the sixth embodiment will be described. Operation of a part that sorts communication data sent from the transmitting terminal 10 by priority in the priority order determination unit 23, and a part that distributes communication data to the receiving terminal 30 or discards a low-priority packet according to the congestion state Is omitted since it is the same as the conventional example.

In the sixth embodiment, when there is a discarded packet, the non-communication time measuring unit 120 adds the continuous non-communication time to the continuous non-communication time 130 in the built-in table as shown in FIG. At this time, if the distribution is successful even once, the continuous non-communication time 130 is returned to 0, and the current priority 101 is also returned to the basic priority 103. The low-priority packet transmission-one determining unit 121 raises the priority of low-priority communication data based on the table shown in FIG. 13 using the same algorithm as in the first embodiment.

As described above, according to the sixth embodiment, the non-communication time measuring unit 120 counts the time during which the low-priority communication data is continuously discarded.
When the communication is continuously stopped for a certain period of time or more, the low-priority packet transmission determining unit 121 can avoid the non-communication state of the low-priority communication data by replacing the high-priority communication data with the distributed high-priority communication data. When a bad congestion state occurs continuously, even low-priority communication data with a low communication frequency can be communicated at regular intervals, which has the effect of preventing loss of communication data for a long time.

[0051]

As described above, according to the present invention, a priority determining unit for receiving communication data transmitted from a transmitting terminal and rearranging the data in order of priority, and detecting and monitoring the congestion state of a plurality of receiving terminals. The congestion state detection unit, the communication data rearranged by the priority order determination unit and the communication data to be distributed to each receiving terminal based on the degree of congestion state detected by the congestion state detection unit, low-priority In a communication control device including a communication data discarding unit that discards communication data, a discard information storage unit that stores the number of continuous discards of low-priority communication data discarded by the communication data discarding unit for each priority, Provided between the priority order determining unit and the communication data discarding unit, and based on the number of consecutive discards stored in the discarding information storage unit, set the priority of low-priority communication data to high priority. Since a low-priority communication data transmission determining unit to be provided to the communication data discarding unit in place of the communication data is provided, high-priority communication can be ensured, and low-priority communication data can be communicated under certain conditions. At the same time, it is possible to prevent the communication sequence of the low-priority communication from being redone, and even when a bad congestion state continuously occurs, the low-priority communication can be performed by increasing the priority. In this case, the communicationless state can be avoided, and there is an effect of preventing loss of communication data for a long time.

Also, a priority determining unit that receives communication data transmitted from the transmitting terminal and rearranges the data in order of priority, a congestion state detecting unit that detects and monitors congestion states of a plurality of receiving terminals, A communication data discarding unit that sorts communication data distributed to each receiving terminal based on the degree of the congestion state detected by the congestion state detection unit and the communication data sorted by the communication data and discards low-priority communication data. A communication control device comprising: a control packet instructing unit for instructing a type of a control packet to be delivered as communication data; and a low priority provided between said priority order determining unit and said communication data discarding unit for discarding. When the communication data of the communication control packet indicated by the control packet instructing unit is included in the communication data, the priority of the communication control packet is set to the distribution schedule. Of the communication data having the lowest priority, which is not a communication control packet, and a control packet transmission determining unit for outputting a delivery instruction. The communication amount can be suppressed, and the communication state can be quickly transmitted to the communication partner even in the low-priority communication.

Also, a priority determining unit for receiving communication data transmitted from the transmitting terminal and rearranging the data in order of priority, a congestion state detecting unit for detecting and monitoring a congestion state of a plurality of receiving terminals, A communication data discarding unit that sorts communication data distributed to each receiving terminal based on the degree of the congestion state detected by the congestion state detection unit and the communication data sorted by the communication data and discards low-priority communication data. In the communication control device provided, the size of the communication data rearranged by the above-mentioned priority order determination unit is checked, and the high-priority communication data to be delivered is smaller than a communicable packet size that does not affect the congestion state. First, a search is made for low-priority communication data that fits in the vacant area. Because with a generation unit, can be avoided without any communication of the low-priority communication data, since the communication data of the high priority and low priority without affecting the congestion state can deliver,
This has the effect of preventing loss of long-term communication data in low-priority communication.

Also, a priority determining unit that receives communication data transmitted from the transmitting terminal and rearranges the data in order of priority, a congestion state detecting unit that detects and monitors congestion states of a plurality of receiving terminals, A communication data discarding unit that selects communication data to be distributed to each receiving terminal based on the degree of the congestion state detected by the congestion state detection unit and the communication data that is rearranged, and discards low-priority communication data, A retransmission request processing unit for performing a retransmission request process for communication data discarded by the communication data discarding unit, and a retransmission request requesting unit for requesting the transmission terminal to retransmit the communication data processed by the retransmission request processing unit by the retransmission request processing unit In the communication control device having the above, provided between the retransmission request processing unit and the retransmission request requesting unit, and a retransmission request is issued by the retransmission request processing unit A retransmission number measurement unit that measures the number of retransmissions of one communication data, and a priority change that changes the priority of the communication data to a higher priority based on the number of retransmissions measured by the retransmission number measurement unit and sends the communication data to the retransmission request request unit. , So that low-priority communication data can be distributed by lowering the packet discard rate at the time of retransmission, and even with low-priority communication data, the priority increases as the number of retransmissions increases, resulting in poor congestion. Since transmission can be performed at a fixed rate (time) even to the receiving terminal in the state, there is an effect of preventing loss of communication data for a long time.

Further, the frequency of occurrence of communication data for each priority within a certain time is measured based on the output from the priority order determination unit, and the frequency of occurrence of the measured communication data or the frequency of occurrence of the communication data is detected by the congestion state detection unit. A priority change stop instructing unit for stopping the priority change by the priority change unit based on the congestion state of the receiving terminal, which affects high-priority communication while distributing low-priority communication data. If the amount of high-priority communication data increases, or if the congestion attack on the receiving terminal worsens, the function to raise the priority by retransmission stops, so the high-priority There is an effect that communication data does not stagnate.

Further, a priority determining unit for receiving the communication data transmitted from the transmitting terminal and rearranging the data in order of priority,
A congestion state detection unit that detects and monitors the congestion state of a plurality of reception terminals, and to each reception terminal based on the communication data rearranged by the priority order determination unit and the degree of the congestion state detected by the congestion state detection unit. In a communication control device including a communication data discarding unit for selecting communication data to be distributed and discarding low-priority communication data, a non-communication time of the low-priority communication data discarded by the communication data discarding unit is measured. A non-communication time measuring unit that is provided between the priority order determining unit and the communication data discarding unit, based on the non-communication time measured by the non-communication time measuring unit. A low-priority communication data transmission determining unit that replaces the priority with high-priority communication data and gives it to the above-mentioned communication data discarding unit avoids a non-communication state of low-priority communication data. Can bad if congestion is continuously generated, the low-priority communication data less communication frequency also can perform communication at predetermined intervals, the effect of preventing the loss of long-time communication data.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a communication control device according to Embodiment 1 of the present invention.

FIG. 2 is an explanatory diagram schematically showing an operation of a packet discarding unit 25 according to the first embodiment.

FIG. 3 is a table of contents of a discarded packet information storage unit 50 according to the first embodiment.

FIG. 4 is a flowchart of an algorithm for raising the priority of low-priority communication data by a low-priority packet transmission determining unit 51 according to the first embodiment.

FIG. 5 is a block diagram showing a configuration of a communication control device according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a communication control device according to a third embodiment of the present invention.

FIG. 7 shows a high / low packet combining unit 7 according to the third embodiment.
FIG. 11 is an explanatory diagram of a communication data synthesis image according to 0.

FIG. 8 is a block diagram showing a configuration of a communication control device according to a fourth embodiment of the present invention.

FIG. 9 is a data structure diagram illustrating a priority change reference value referred to by a priority change unit 81 according to the fourth embodiment.

FIG. 10 is a block diagram showing a configuration of a communication control device according to Embodiment 5 of the present invention.

FIG. 11 is a data structure diagram of a stop condition based on a priority change stop instruction unit according to a fifth embodiment.

FIG. 12 is a block diagram showing a configuration of a communication control device according to a sixth embodiment of the present invention.

FIG. 13 is a non-communication time measuring unit 1 according to the sixth embodiment.
FIG. 2 is a structural diagram of information stored at 20.

FIG. 14 is a block diagram illustrating a configuration of a communication control device according to a conventional example.

FIG. 15 is an explanatory diagram schematically showing the operation of the packet discarding unit 25 in the conventional example.

FIG. 16 is a block diagram showing a configuration of a communication control device according to another conventional example.

[Explanation of symbols]

Reference Signs List 10 transmitting terminal, 23 priority determining unit, 24 congestion state detecting unit, 25 packet discarding unit, 28 retransmission request processing unit, 29 retransmission request requesting unit, 30A receiving terminal A, 30
B receiving terminal B, 30C receiving terminal C, 50 discarded packet information storage unit, 51 low priority packet transmission determination unit,
60 control packet instructing unit, 61 control packet transmission determining unit, 70 high / low packet combining unit, 80 retransmission count measuring unit, 82 priority change stop instruction unit, 120 no-communication time measuring unit, 121 low priority packet transmission determining unit.

Claims (6)

[Claims] A priority determining unit that receives communication data transmitted from a transmitting terminal and rearranges the data in a priority order; a congestion state detecting unit that detects and monitors a congestion state of a plurality of receiving terminals; A communication data discarding unit that sorts communication data distributed to each receiving terminal based on the degree of the congestion state detected by the congestion state detection unit and the communication data sorted by the communication data and discards low-priority communication data. A communication control device comprising: a discard information storage unit for storing, for each priority, a continuous discard number of low-priority communication data discarded by the communication data discard unit; a priority order determining unit; and the communication data discard unit. The priority of the low-priority communication data is replaced with the high-priority communication data based on the number of consecutive discards stored in the discard information storage unit. A communication control device being characterized in that a low-priority communication data transmission determining section that gives the data discard unit. 2. A priority determining unit for receiving communication data transmitted from a transmitting terminal and rearranging the data in order of priority, a congestion state detecting unit for detecting and monitoring a congestion state of a plurality of receiving terminals, and the priority determining unit A communication data discarding unit that sorts communication data distributed to each receiving terminal based on the degree of the congestion state detected by the congestion state detection unit and the communication data sorted by the communication data and discards low-priority communication data. A communication control device comprising: a control packet instructing unit for instructing a type of a control packet to be distributed as communication data; If the communication data includes a communication control packet specified by the control packet indicating unit, the priority of the communication control packet is set to the distribution schedule. In the communication data, low top priority,
A communication control device, comprising: a control packet transmission determining unit that outputs a distribution instruction by exchanging communication data that is not a communication control packet. 3. A priority determining unit that receives communication data transmitted from a transmitting terminal and sorts the data in order of priority, a congestion state detecting unit that detects and monitors a congestion state of a plurality of receiving terminals, and the priority determining unit. A communication data discarding unit that sorts communication data distributed to each receiving terminal based on the degree of the congestion state detected by the congestion state detection unit and the communication data sorted by the communication data and discards low-priority communication data. In the communication control device provided, the size of the communication data rearranged by the priority order determination unit is checked, and high-priority communication data to be distributed is
When the packet size is less than or equal to the communicable packet size that does not affect the congestion state, low-priority communication data that fits in the empty area is searched for. A communication control device, comprising: 4. A priority determining unit that receives communication data transmitted from a transmitting terminal and rearranges the data in order of priority, a congestion state detecting unit that detects and monitors a congestion state of a plurality of receiving terminals, and the priority determining unit. A communication data discarding unit that selects communication data to be distributed to each receiving terminal based on the degree of the congestion state detected by the congestion state detection unit and the communication data that is rearranged, and discards low-priority communication data, A retransmission request processing unit that performs retransmission request processing of communication data discarded by the communication data discarding unit; and a retransmission request request unit that requests the transmission terminal to perform a retransmission request of communication data that has been retransmitted by the retransmission request processing unit. A communication control device provided between the retransmission request processing unit and the retransmission request requesting unit, wherein the retransmission request is transmitted by the retransmission request processing unit. A retransmission number measurement unit that measures the number of retransmissions of one communication data; and a priority change that changes the priority of the communication data to a higher priority based on the number of retransmissions measured by the retransmission number measurement unit and sends the priority to the retransmission request request unit. And a communication control device. 5. The communication control device according to claim 4, wherein a frequency of occurrence of communication data for each priority within a predetermined time is measured based on an output from said priority order determination unit, and A communication control apparatus comprising a priority change stop instruction unit for stopping the priority change by the priority change unit based on the occurrence frequency or the congestion state of the receiving terminal detected by the congestion state detection unit. . 6. A priority determining unit that receives communication data transmitted from a transmitting terminal and rearranges the data in order of priority, a congestion state detecting unit that detects and monitors a congestion state of a plurality of receiving terminals, and the priority determining unit. A communication data discarding unit that sorts communication data distributed to each receiving terminal based on the degree of the congestion state detected by the congestion state detection unit and the communication data sorted by the communication data and discards low-priority communication data. A communication control device comprising: a non-communication time measuring unit that measures non-communication time of low-priority communication data discarded by the communication data discarding unit; And replaces the priority of the low-priority communication data with the high-priority communication data based on the non-communication time measured by the non-communication time measuring unit. Providing the discard unit communication control device being characterized in that a low-priority communication data transmission determining unit.