WO2015155996A1

WO2015155996A1 - Communication control apparatus, communication control method, and recording medium on which communication control program has been stored

Info

Publication number: WO2015155996A1
Application number: PCT/JP2015/002018
Authority: WO
Inventors: 由明西川
Original assignee: 日本電気株式会社
Priority date: 2014-04-10
Filing date: 2015-04-10
Publication date: 2015-10-15
Also published as: JPWO2015155996A1; JP6528768B2

Abstract

Provided is a communication control apparatus that can shorten delays even if all pieces of data transmitted to communication paths are subjected to loss during a time sufficiently longer than an interval between transmissions of the data that are intermittently transmitted. The communication control apparatus comprises: a management means that maintains a plurality of connections to a transmission destination apparatus; and a changing means. A determination means detects a temporary disconnection, which is a state that a communication performed by a data transmission means via a selected connection that is selected from the plurality of connections has been interrupted, and transmits a notification of temporary disconnection upon detection of the temporary disconnection. The changing means receives, from the determination means, the notification of temporary disconnection. A switching detection means detects a communication path switching performed between the data transmission means and the transmission destination apparatus, and transmits a notification of switching upon detection of a completion of the switching. When having received, from the switching detection means, the notification of switching within a predetermined time period based on the notification of temporary disconnection, the changing means selects a new selected connection from the plurality of connections except the foregoing selected connection, and transmits the identifier of the new selected connection to the data transmission means.

Description

Communication control apparatus, communication control method, and recording medium for storing communication control program

The present invention relates to a technology for controlling communication.

In packet communication, which is generally used in Internet communication, packet loss and route change occur on the route. For this reason, in communication using the packet switching method, retransmission control and order control are required in order to deliver transmitted data to a receiving terminal in the order of transmission.

In retransmission control, for example, when a transmission acknowledgment (ACK; Acknowledgment) indicating that data has been delivered to the receiving side is not received for a certain period of time, retransmission of the data is started. Alternatively, in the retransmission control, for example, when the transmission side receives a non-delivery acknowledgment (NACK) indicating that data has not been delivered to the reception side, retransmission of the data is started. Alternatively, in the retransmission control, for example, when the number of received data is changed by a change in order on the receiving side, retransmission of the data whose order has been changed is started.

For example, in TCP (Transmission Control Protocol), when a transmission side does not receive an ACK for a certain period after transmitting a segment, the segment is retransmitted. A segment is a communication unit in TCP. Furthermore, in TCP, even when it is determined by duplicate ACK that the number of segments received by changing the order is equal to or greater than a threshold value, the data in which the segments are generated is retransmitted. The specific number of the threshold values varies depending on the OS (Operating System) and settings.

In order control, when data is received on the receiving side in a different order from the transmission order, the received data are arranged in the order of transmission.

For example, in TCP, when a transmitted segment arrives at the receiving side, if a segment sent before that segment has not arrived at the receiving side, the receiving side of the segment sent before it has not arrived Waiting for arrival. Then, the segments are rearranged in the order of transmission and then passed to a higher-level protocol or application.

When data loss (that is, loss) occurs in the communication path, retransmission control and order control for waiting for retransmission are performed. A large delay occurs in communication due to the retransmission control and the sequence control for waiting for retransmission. The communication using the packet switching method has a problem that such a delay occurs. An example of a data communication method that avoids this order control is described in Patent Document 1.

Patent Document 1 describes a cyclic transmission method that avoids order control by sequentially transmitting different data for each of a plurality of connections. As described above, in the cyclic transmission method described in Patent Document 1, low-delay communication is realized by avoiding order control. In this method, the transmitting apparatus transmits different data in order for each of the established connections. The receiving device can use the arrived data at any time in the application program being executed. The device on the transmission side described in Patent Document 1 identifies the difference between the largest number and the smallest number among the numbers assigned to each segment that is being transmitted via any connection according to the order of transmission. To do. When the identified difference is equal to or larger than the predetermined value, the transmitting side apparatus retransmits the earliest transmitted segment through another connection. Therefore, even if an accidental loss occurs during segment transmission, it is possible to avoid the order control for waiting for retransmission.

Patent Document 2 describes a relay node and a destination node connected by an active communication path and a backup communication path. When a failure occurs in the communication link of the working communication path, the relay node switches the communication path to be used to the backup communication path. Then, the relay node retransmits the data transmitted between the occurrence of the failure and the completion of the switching of the communication path.

JP 2010-056990 A Japanese Patent Laid-Open No. 11-308233

For example, switching of communication paths such as handover in a mobile network may cause a situation in which all data transmitted to each communication path is lost over a period sufficiently longer than the transmission interval of intermittently transmitted data. In that case, in data transmission according to the cyclic transmission method as described in Patent Document 1, retransmission control is performed in all connections established in that period. Therefore, in the above case, the order control cannot be avoided in the data communication according to the cyclic transmission method as described in Patent Document 1. Therefore, in the technique of Patent Document 1, when all data transmitted by switching the communication path is lost for a period sufficiently longer than the transmission interval of intermittently transmitted data, the communication delay cannot be shortened.

The relay node described in Patent Document 2 switches a communication path to be used to a backup communication path, which is the other communication path, when a failure occurs in an active communication path out of two communication paths. Therefore, when a situation occurs in which all data transmitted within a period sufficiently longer than the transmission interval of intermittently transmitted data occurs, not only the communication link via the working communication path but also the communication link via the backup communication path A failure also occurs. Accordingly, in that case, a failure occurs in all communications, so retransmission control is performed in communication links via all communication paths. As described above, in the technique of Patent Document 2, when all data transmitted by switching the communication path is lost for a period sufficiently longer than the transmission interval of intermittently transmitted data, the communication delay cannot be shortened. .

One of the objects of the present invention is communication that can reduce communication delay even when all data transmitted by switching the communication path is lost for a period sufficiently longer than the transmission interval of intermittently transmitted data. It is to provide a control device and the like.

The communication control device according to an aspect of the present invention includes a management unit that maintains a plurality of connections to a transmission destination device, and a communication to the transmission destination device that is performed by a data transmission unit via a selected connection selected from the plurality of connections. In addition to receiving the temporary disconnection notification from the determination unit that detects the temporary disconnection in a state in which the temporary interruption is detected and detecting the temporary disconnection, the data transmission unit and The switching notification is detected within a predetermined period based on the temporary disconnection notification from the switching detection means that detects switching of the communication path with the transmission destination device and detects the completion of the switching. If received, the new selected connection is selected from the plurality of connections other than the selected connection, and the selected connection identifier is selected. And a changing means for transmitting to said data transmission means.

The communication control method according to an aspect of the present invention maintains a plurality of connections to a destination device, and communication with the destination device performed by a data transmission unit via a selected connection selected from the plurality of connections is interrupted. In addition to receiving the temporary disconnection notification from the determination unit that detects the temporary disconnection that is in a state and transmits the temporary disconnection notification in response to detecting the temporary disconnection, the data transmission unit and the transmission destination When the switching notification is received within a predetermined period based on the temporary disconnection notification from the switching detection unit that detects switching of the communication path with the device and detects the completion of the switching when the switching is detected. , Selecting a new selected connection from the plurality of connections other than the selected connection, and specifying an identifier of the selected selected connection as the data To send to the signal means.

The recording medium according to one aspect of the present invention includes: a management unit that maintains a plurality of connections to a transmission destination device; and a transmission destination device that a data transmission unit performs via a selected connection selected from the plurality of connections. In addition to receiving the temporary disconnection notification from the determination unit that detects the temporary disconnection in a state in which communication with respect to the communication is interrupted and detects the temporary disconnection, the data transmission The switching is detected within a predetermined period based on the temporary disconnection notification from the switching detection unit that detects switching of the communication path between the unit and the destination device and transmits a switching notification when the completion of the switching is detected. When the notification is received, a new selected connection is selected from the plurality of connections other than the selected connection, and the selected selection connection is selected. Changing means for transmitting a down identifiers to said data transmission means, for storing a communication control program for operating in. The present invention can also be realized by a communication control program stored in the recording medium.

Even when all the data transmitted by switching the communication path is lost for a period sufficiently longer than the transmission interval of intermittently transmitted data, there is an effect that communication delay can be reduced.

FIG. 1 is a diagram illustrating an example of a configuration of a communication system 10 according to the first and second embodiments of the present invention. FIG. 2 is a flowchart illustrating an example of an operation of detecting the occurrence of a temporary disconnection in the second communication device 2 of the first and second embodiments. FIG. 3 is a flowchart illustrating an example of an operation when the communication control device 3 according to the first and second embodiments receives a temporary disconnection notification. FIG. 4 is a block diagram illustrating an example of a configuration of a communication system 10B according to the third exemplary embodiment of the present invention. FIG. 5 is a block diagram illustrating an example of the operation of the second communication device 2B according to the third embodiment. FIG. 6 is a flowchart illustrating an example of the operation of the communication control device 3B of the third embodiment. FIG. 7 is a block diagram illustrating an example of a configuration of a communication system 10A according to a modification of the first embodiment. FIG. 8 is a diagram illustrating an example of the configuration of the communication control device 3C according to the fourth embodiment of the present invention. FIG. 9 is a diagram illustrating an example of a configuration of a computer 1000 that can realize the communication control device and the communication device according to the present invention.

Next, embodiments of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
FIG. 1 is a diagram illustrating an example of a configuration of a communication system 10 according to the present embodiment. Referring to FIG. 1, a communication system 10 includes a first communication device 1 and a second communication device 2. The 1st communication apparatus 1 and the 2nd communication apparatus 2 are connected so that communication is possible. The communication path connecting the first communication device 1 and the second communication device 2 is switched irregularly, for example. For example, the first communication device 1 and the second communication device 2 are connected by wireless communication via a base station. Then, when a handover is performed due to movement of the first communication device 1 or the second communication device 2, the communication path that connects the first communication device 1 and the second communication device 2 is switched. The first communication device 1 and the second communication device 2 perform connection-type communication, which is communication performed in a state where a connection that is a virtual dedicated communication path is established. An example of connection-type communication performed between the first communication device 1 and the second communication device 2 is communication using TCP. Communication performed between the first communication device 1 and the second communication device 2 may not be communication by TCP. In the present embodiment and other embodiments of the present invention, the first communication device 1 is also referred to as a transmission device. Further, the second communication device 2 is also expressed as a transmission destination device.

The first communication device 1 includes a data transmission unit 101 and a communication control device 3. The communication control device 3 includes a management unit 102, a changing unit 103, a notification receiving unit 104, and a switching detection unit 105. The management unit 102, the change unit 103, the notification reception unit 104, and the switching detection unit 105 may be components of the first communication device 1. The management unit 102, the change unit 103, the notification reception unit 104, and the switch detection unit 105 may operate as the communication control device 3.

The second communication device 2 includes a data reception unit 201, a determination unit 202, and a notification transmission unit 203.

The data transmission unit 101 transmits data at a predetermined timing. For example, the data transmission unit 101 may transmit data at a predetermined interval.

The management unit 102 manages a plurality of connections established in the first communication device 1. The management unit 102 manages a plurality of connections including connections used for data transmission. The management of the connection is, for example, performing a process for maintaining the established state so that the connection is not disconnected.

The data reception unit 201 receives data transmitted by the data transmission unit 101 of the first communication device 1.

When the time interval at which the data reception unit 201 receives data exceeds a predetermined threshold, the determination unit 202 has a “communication channel temporary disconnection” in which the communication channel is temporarily disconnected. Is determined. In the description of this embodiment and other embodiments, the communication path temporary interruption is also referred to as “temporary interruption”.

When the determination unit 202 determines that a communication path temporary disconnection has occurred, the notification transmission unit 203 sends a “communication path temporary disconnection notification” that is a notification indicating that the communication path temporary disconnection has occurred. Transmit to the first communication device 1. In the description of this embodiment and other embodiments, the communication path temporary interruption notification is also referred to as “temporary interruption notification”.

The notification reception unit 104 receives a communication path temporary disconnection notification from the notification transmission unit 203 of the second communication device 2.

The switching detection unit 105 monitors the switching of the communication path. For example, the switching detection unit 105 may always monitor switching of the communication path. Then, the switching detection unit 105 detects the completion of switching of the communication path.

The change unit 103 is used for data transmission from a plurality of connections managed by the management unit 102 when the notification reception unit 104 receives the temporary disconnection notification and the switching detection unit 105 detects completion of switching of the communication path. Select a connection that is not connected. In the description of the present embodiment, the selected connection is also referred to as a selected connection. The changing unit 103 designates the selected connection as a connection used for data transmission. For example, the changing unit 103 may designate the selected connection as a connection used for data transmission by transmitting the identifier of the selected connection to the data transmitting unit 101. In this case, for example, when receiving the connection identifier, the data transmission unit 101 may be designed to change the connection used for data transmission to the connection specified by the received identifier. In the following description, the connection used by the data transmission unit 101 for data transmission is also referred to as a transmission connection.

Next, operations of the first communication device 1 and the second communication device 2 of the present embodiment will be described in detail with reference to the drawings.

FIG. 2 is a flowchart showing an example of an operation of detecting the occurrence of a temporary disconnection in the second communication device 2 of the present embodiment. At the start of the operation illustrated in FIG. 2, the data transmission unit 101 of the first communication device 1 transmits data. The data transmission unit 101 may transmit data by any transmission method based on TCP, for example. For example, the data transmission unit 101 transmits data at predetermined time intervals.

When data is transmitted to the data receiving unit 201 (Yes in step S101), first, the data receiving unit 201 receives the data transmitted by the data transmitting unit 101 (step S102). A method for receiving data by the data receiving unit 201 may be any method that can receive data transmitted by the data transmitting unit 101. For example, when the data transmission unit 101 transmits data based on TCP, the data reception unit 201 may receive the transmitted data similarly based on TCP. The data receiving unit 201 may transmit the time when the data is received to the determination unit 202. When the data receiving unit 201 receives the data, for example, the data receiving unit 201 may transmit a notification indicating that the data has been received to the determining unit 202. In this case, the determination unit 202 may regard the time when the notification indicating that the data has been received is received as the time when the data reception unit 201 receives the data. When data is not transmitted (No in step S101), the communication control device 3 performs the operation of step S103.

The determination unit 202 determines whether or not the data reception interval, which is the time interval at which the data reception unit 201 receives the data, exceeds a threshold (step S103). The determination unit 202 only needs to store the time when the data reception unit 201 last received data. And the determination part 202 should just specify the time which passed since the data reception part 201 received the data last. When the time elapsed from the time when the data reception unit 201 last received data exceeds the threshold, the determination unit 202 may determine that the data reception interval exceeds the threshold. As described above, when it is determined that the data reception interval exceeds the threshold, the determination unit 202 determines that a temporary interruption has occurred. If the time elapsed since the data reception unit 201 last received data does not exceed the threshold, the determination unit 202 may determine that the data reception interval does not exceed the threshold. If it is determined that the data reception interval does not exceed the threshold value, the determination unit 202 determines that no interruption has occurred. The determination unit 202 may determine whether the data reception interval exceeds a predetermined threshold based on the stored time and the time when the data reception unit 201 newly receives data. The above threshold value may be given in advance. Alternatively, for example, the determination unit 202 may determine the above-described threshold based on an interval at which the data reception unit 201 receives data within a predetermined period.

If the data reception interval does not exceed the predetermined threshold (No in step S103), the second communication device 2 next performs the operation of step S101. The data receiving unit 201 waits for the next data transmitted from the first communication device 1.

If the data reception interval exceeds the predetermined threshold (Yes in step S103), the notification transmission unit 203 transmits a temporary disconnection notification to the notification reception unit 104 (step S104). Then, the second communication device 2 ends the operation shown in FIG. After the operation in step S104, the operation of the second communication device 2 may return to step S102.

Next, the operation of the communication control device 3 when receiving a temporary disconnection notification will be described.

FIG. 3 is a flowchart showing an example of the operation when the communication control device 3 of the present embodiment receives a temporary disconnection notification. When the notification transmission unit 203 of the second communication device 2 transmits a temporary disconnection notification, the communication control device 3 performs the operation shown in FIG. Further, the switching detection unit 105 of the communication control device 3 monitors a communication path used in communication between the first communication device 1 and the second communication device 2. When the switching of the communication path used in the communication between the first communication device 1 and the second communication device 2 occurs, the switching detection unit 105 detects the completion of the switching.

When the notification transmission unit 203 transmits a temporary suspension notification, the notification reception unit 104 receives the temporary suspension notification (step S111). The notification receiving unit 104 may transmit the received temporary disconnection notification to the changing unit 103.

The changing unit 103 that has received the temporary suspension notification identifies the time based on the temporary suspension notification, and sets the identified time as the reference time. The time based on the temporary suspension notification may be, for example, the time when the changing unit 103 receives the temporary suspension notification. The time based on the temporary disconnection notification may be, for example, the time when the notification receiving unit 104 receives the temporary disconnection notification. The time based on the temporary suspension notification may be the time at which the temporary suspension notification is transmitted. In that case, the notification transmission unit 203 may transmit the transmission time of the temporary suspension notification to the notification reception unit 104 in addition to the temporary suspension notification. The time based on the temporary disconnection notification may be the time when the determination unit 202 determines that the temporary disconnection has occurred. In that case, the determination unit 202 may transmit a data value representing the time at which it was determined that a temporary interruption has occurred to the notification transmission unit 203. Then, in addition to the temporary disconnection notification, the notification transmission unit 203 may transmit a data value representing the time when it is determined that the temporary disconnection has occurred to the notification reception unit 104.

Furthermore, the changing unit 103 sets a detection period based on the reference time. Then, the changing unit 103 determines whether or not switching of the communication path is detected within the detection period (step S112).

The detection period is a period determined based on the reference time, for example. The length of the detection period may be a period of a predetermined length. In this case, the changing unit 103 may set, for example, a reference time or a time that is a predetermined time before the reference time as the start time of the detection period. And the change part 103 should just set the time after predetermined time rather than reference | standard time or reference | standard time as an end time of a detection period, for example. The length of the detection period may not be determined. In this case, the changing unit 103 may set, for example, a reference time or a time that is a predetermined time before the reference time as the start time of the detection period. Then, the changing unit 103 may set the maximum value that can be set as the time as the end time of the detection period. The changing unit 103 may not determine the end time of the detection period. Since the reference time is a time based on the temporary suspension notification, the detection period can be regarded as a period determined based on the temporary suspension notification.

For example, when the first communication device 1 is communicating with the second communication device 2 wirelessly, switching of the communication path also occurs, for example, when the wireless base station that relays wireless communication is switched. Generally, a device that communicates by radio has information that identifies a radio base station that relays communication. For example, the switching detection unit 105 may detect the switching of the communication path by detecting a change of a wireless base station that relays wireless communication performed by the first communication device 1. The switching detection unit 105 may detect the switching of the communication path by a method according to the type of the communication line to which the first communication device 1 is connected.

If the switching of the communication path is not detected within the detection period (No in step S112), the communication control device 3 next performs the operation of step S111. That is, the notification receiving unit 104 waits for a temporary disconnection notification to be transmitted next.

When the end time is set in the detection period corresponding to the reception of the temporary disconnection notification and the switching of the communication path is not detected within the detection period, the communication control device 3 performs processing based on the temporary disconnection notification. Absent. That is, when the switching of the communication path is not detected within the detection period corresponding to reception of the temporary disconnection notification, the communication control device 3 ignores the temporary disconnection notification.

When switching of the communication path is detected within the detection period (Yes in step S112), the changing unit 103 is a transmission connection that is a connection used by the data transmitting unit 101 to transmit data to the second communication device 2. Is changed (step S113). And the communication control apparatus 3 complete | finishes the operation | movement shown in FIG. After step S113, the operation of the communication control device 3 may return to step S111.

As described above, when the end time of the detection period is not determined, the change unit 103 waits for detection of switching of the communication path by the switching detection unit 105. In that case, the change unit 103 switches the communication path whenever the switching of the communication path is detected whenever the temporary disconnection notification is received.

This embodiment has an effect that communication delay can be reduced even when all data is lost due to switching of the communication path for a period sufficiently longer than the transmission interval of intermittently transmitted data.

The reason is that, when it is notified that the occurrence of a communication path temporary interruption has been determined, the change unit 103 changes the transmission connection after the switching detection unit 105 detects the completion of the switching of the communication path. is there.

When the communication path is switched, the transmitted data is lost in the connection in which the data is transmitted before the switching of the communication path is completed, so the order control is performed. When the transmission connection is switched before the switching of the communication path is completed, data is transmitted through the transmission connection after the switching, and all the transmitted data is lost. Therefore, order control is also performed in the transmission connection after switching. If each of the plurality of connections is sequentially switched to the transmission connection before the switching of the communication path is completed, the order control is performed on all of the plurality of connections. Therefore, even if the switching of the communication path is completed, the sequence control is performed in all of the plurality of connections, so that further delay occurs in the communication.

On the other hand, in this embodiment, since the transmission connection is changed after the completion of the switching of the communication path is detected, the order control is performed except for the connection set as the transmission connection when the switching of the communication path is performed. Not implemented. Therefore, the order control is not performed on the changed transmission connection after the completion of the switching of the communication path is detected. Therefore, there is no communication delay caused by the order control. Therefore, in this embodiment, communication delay can be shortened.

<Second Embodiment>
Next, a second embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram illustrating a configuration of a communication system 10 according to the present embodiment. The configuration of the communication system 10 according to the present embodiment is the same as the configuration of the communication system 10 according to the first embodiment. Below, it demonstrates focusing on the difference between this embodiment and 1st Embodiment.

In this embodiment, the data transmission unit 101 transmits a transmission time that is a time at which the data is transmitted in addition to the data to be transmitted. The data transmission unit 101 may add transmission time data that is data representing the transmission time of the data to the transmission data that is data to be transmitted. Then, the data transmission unit 101 may transmit the transmission data to which the transmission time data is added to the second communication device 2.

The data reception unit 201 of the second communication device 2 transmits the transmission time data added to the received transmission data to the determination unit 202.

The determination unit 202 stores the transmission time data added to the transmission data last received by the data reception unit 201. When the data reception unit 201 newly receives transmission data, the determination unit 202 determines whether the data reception interval exceeds a threshold, as in the determination unit 202 of the first embodiment. When the data reception interval does not exceed the threshold value, the determination unit 202 stores the transmission time data transmitted in addition to the newly received transmission data as the last received transmission data. When the data reception interval exceeds the threshold, the determination unit 202 transmits the stored transmission time data added to the last received transmission data to the notification transmission unit 203.

When the data reception interval exceeds the threshold value, the notification transmission unit 203 transmits the transmission time data stored in the determination unit 202 in addition to the temporary disconnection notification. In that case, the notification transmission unit 203 may add transmission time data to the temporary disconnection notification. And the notification transmission part 203 should just transmit the temporary stop notification to which transmission time data was added.

The notification reception unit 104 receives transmission time data from the notification transmission unit 203 in addition to the temporary disconnection notification. The notification receiving unit 104 only has to receive the temporary disconnection notification to which the transmission time data is added as described above.

The changing unit 103 sets the time represented by the transmission time data received by the notification receiving unit 104 as the start time of the detection period.

Note that the transmission time data may be a data value representing the transmission time. The transmission time data may be, for example, a sequence number or ID (Identifier) assigned to each of the transmitted data, which can specify the order of transmission. The transmission time data may be, for example, a data reception time that is a time when the data receiving unit 201 receives the data.

When the transmission time data is a sequence number, the changing unit 103 may hold, for example, the transmission time and sequence number of the data for which the transmission time is specified and the transmission interval in advance. In the following description, the transmission time of data for which the transmission time is specified and held by the changing unit 103 is referred to as a reference transmission time. Further, the sequence number of the data for which the transmission time is specified and held by the changing unit 103 is referred to as a reference sequence number. The reference sequence number may be an initial value of the sequence number. In this case, the reference transmission time may be a time at which data with an initial sequence number is transmitted. For example, the changing unit 103 may acquire the initial value of the sequence number, the transmission time of the data to which the sequence number that is the initial value, and the transmission interval are obtained from the data transmitting unit 101 in advance. The changing unit 103 may specify the number of times data is transmitted after the reference time based on the difference between the sequence number received by the notification receiving unit 104 and the reference sequence number. Based on the number of times the data has been updated since the reference time and the transmission interval at which the data is transmitted, the changing unit 103 has transmitted the data to which the sequence number received by the notification receiving unit 104 is added from the reference time What is necessary is just to estimate the time elapsed until the time. As described above, the changing unit 103 assigns the sequence number received by the notification receiving unit 104 based on the sequence number received by the notification receiving unit 104 as the transmission time data, the reference transmission time and the reference sequence number, and the transmission interval. Estimate the time when the transmitted data was transmitted.

When the notification transmitting unit 203 transmits a data value representing the reception time, which is the time when the data receiving unit 201 receives the data, as the transmission time data, the changing unit 103 is more than the time represented by the received transmission time data. The time before the delay time may be estimated as the transmission time. The delay time may be a representative value of the time required for data transmission from the first communication device 1 to the second communication device 2. The representative value may be, for example, an average value, an intermediate value, or another statistical value derived experimentally.

Next, operations of the first communication device 1 and the second communication device 2 of the present embodiment will be described in detail with reference to the drawings. Hereinafter, a case where the data transmission unit 101 transmits data to which transmission time data representing the data transmission time is added will be described.

FIG. 2 is a flowchart showing an example of an operation of detecting the occurrence of a temporary disconnection in the second communication device 2 of the present embodiment.

When the data is transmitted to the data receiving unit 201 (Yes in step S101), the data receiving unit 201 receives the data to which the transmission time data is added (step S102). When data is not transmitted to the data receiving unit 201 (No in step S101), the communication control device 3 next performs the operation of step S103.

The operation of the determination unit 202 in step S103 is the same as the operation in step S103 of the determination unit 202 of the first embodiment. As described above, the determination unit 202 only needs to store the time when the data reception unit 201 last received data. In step S <b> 103, the determination unit 202 determines whether the data reception interval exceeds the threshold value by comparing the threshold value with the time elapsed since the data reception unit 201 last received the data. do it. Whether the data reception interval exceeds the threshold value is determined by comparing the threshold value with the time elapsed from the stored time to the time when the data receiving unit 201 newly received the data. It may be determined.

If the data reception interval does not exceed the predetermined threshold (No in step S103), the communication control device 3 next performs the operation of step S101. Then, the data receiving unit 201 continues to receive data.

If the data reception interval exceeds a predetermined threshold as a result of determination by the determination unit 202 (Yes in step S103), the notification transmission unit 203 transmits transmission time data in addition to the temporary disconnection notification (step S104). ).

FIG. 3 is a flowchart showing an example of the operation when the communication control device 3 of the present embodiment receives a temporary disconnection notification.

First, the notification receiving unit 104 receives, for example, a temporary suspension notification and transmission time data added to the temporary suspension notification. (Step S111).

When the notification receiving unit 104 receives the temporary disconnection notification and the transmission time data added to the temporary disconnection notification, the switching detection unit 105 determines the detection period. First, the switch detection unit 105 identifies the time represented by the transmission time data received by the notification reception unit 104. The switch detection unit 105 sets the specified time as the start time of the detection period. The switching detection unit 105 determines the end time of the detection period according to a predetermined determination method. For example, the switching detection unit 105 may determine the end time of the detection period by any one of the methods for determining the end time of the detection period in the first embodiment.

When the switching detection unit 105 detects switching of the communication path within the detection period (Yes in step S112), the changing unit 103 changes the transmission connection in the same manner as the changing unit 103 of the first embodiment (step S113). ). If the switching detection unit 105 detects switching of the communication path within the detection period (No in step S112), the communication control device 3 next performs, for example, the operation of step S111.

This embodiment has the same effect as the first embodiment. The reason is the same as the reason for the effect of the first embodiment.

This embodiment has a second effect that communication delay can be further reduced.

The reason is that the change unit 103 changes the transmission connection when the switching of the communication path is detected in the detection period in which the transmission time of the last transmitted data or the estimated time of the transmission time is the start time. It is. Therefore, even when the fluctuation of the period during which all transmitted data is lost is large, the period can be specified more accurately. Therefore, the sequence control can be avoided more reliably, and the communication delay can be shortened. In addition, since the lost data can be accurately grasped, only the lost data can be transmitted through the changed transmission connection. Therefore, communication delay can be further reduced.

<Third Embodiment>
Next, a third embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 4 is a block diagram illustrating an example of the configuration of the communication system 10B according to the present embodiment.

Referring to FIG. 4, the communication system 10B includes a first communication device 1B and a second communication device 2B. The first communication device 1B and the second communication device 2B can communicate with each other.

The first communication device 1B includes a data transmission unit 101 and a communication control device 3B.

The communication control device 3B includes a management unit 102, a change unit 103, a delivery confirmation reception unit 106, a determination unit 107, and a switching reception unit 108.

The second communication device 2B includes a data reception unit 201, a delivery confirmation transmission unit 204, a switching detection unit 205, and a switching transmission unit 206.

The data transmission unit 101 and the data reception unit 201 operate in the same manner as the data transmission unit 101 and the data reception unit 201 of the first embodiment, respectively.

The management unit 102 manages a plurality of connections established between the first communication device 1B and the second communication device 2B, as with the management unit 102 of the first embodiment.

When the data reception unit 201 receives data, the delivery confirmation transmission unit 204 transmits a delivery confirmation regarding the data to the first communication device 1B. The delivery confirmation may be, for example, a predetermined data value or signal.

The delivery confirmation receiving unit 106 receives the delivery confirmation from the delivery confirmation transmitting unit 204 of the second communication device 2B. When the delivery confirmation is received, the delivery confirmation receiving unit 106 transmits, for example, the time when the delivery confirmation is received to the determination unit 107.

The determination unit 107 stores the time when the delivery confirmation receiving unit 106 last received the delivery confirmation. When the determination unit 107 receives a time when a new delivery confirmation is received from the delivery confirmation receiving unit 106, the delivery confirmation receiving unit 106 receives the delivery confirmation based on the stored time and the newly received time. The interval to be derived is derived. The determination unit 107 determines whether the interval at which the delivery confirmation receiving unit 106 receives the delivery confirmation exceeds a predetermined threshold. When the interval at which the delivery confirmation receiving unit 106 receives the delivery confirmation exceeds a predetermined threshold, the judging unit 107 determines that a communication path temporary interruption has occurred. When the interval at which the delivery confirmation receiving unit 106 receives the delivery confirmation exceeds a predetermined threshold, the determination unit 107 transmits a temporary suspension notification to the change unit 103.

The switching detection unit 205 monitors switching of the communication path used for data transmission between the first communication device 1B and the second communication device 2B, as with the switching detection unit 105 of the first embodiment. To do. Then, the switching detection unit 205 detects the completion of switching of the communication path.

The switching transmission unit 206 transmits a switching notification to the first communication device 1B when the switching detection unit 205 detects the completion of switching of the communication path. The switching notification may be, for example, a predetermined data value or signal.

The switch receiving unit 108 receives a switch notification from the second communication device 2B.

The change unit 103 receives a temporary disconnection notification from the determination unit 107. For example, the changing unit 103 sets the time at which the suspension notification is received as the reference time. The change unit 103 may set the time at which the determination unit 107 determines that a communication path temporary interruption has occurred as the reference time. In that case, the changing unit 103 may receive the time when the determining unit 107 determines that the communication path temporary interruption has occurred from the determining unit 107. And the change part 103 sets a detection period based on reference | standard time similarly to the change part 103 of 1st Embodiment. When the switching receiving unit 108 receives a switching notification within the set detection period, the changing unit 103 changes the transmission connection in the same manner as the changing unit 103 of the first embodiment.

Next, the operation of the second communication device 2B of this embodiment will be described in detail with reference to the drawings.

FIG. 5 is a block diagram illustrating an example of the operation of the second communication device 2B of the present embodiment. At the start of the operation illustrated in FIG. 5, the data transmission unit 101 of the first communication device 1B transmits data to the second communication device 2B.

The data receiving unit 201 receives data (step S201).

In response to the data receiving unit 201 receiving data, the delivery confirmation transmitting unit 204 transmits a delivery confirmation to the first communication device 1B (step S202).

As described above, the switching detection unit 205 monitors the switching of the communication path between the first communication device 1B and the second communication device 2B. Then, the switching detection unit 205 detects completion of switching of the communication path. If switching of the communication path is not detected by the switching detection unit 205 (No in step S203), the second communication device 2B next performs, for example, the operation of step S201. Then, the data receiving unit 201 waits until the next data is sent. When switching of the communication path is detected by the switching detection unit 205 (Yes in step S203), the switching detection unit 205 transmits a switching notification to the first communication device 1B (step S204).

Next, the operation of the communication control device 3B of this embodiment will be described in detail with reference to the drawings.

FIG. 6 is a flowchart showing an example of the operation of the communication control device 3B of the present embodiment. At the start of the operation shown in FIG. 6, the data transmission unit 101 transmits data to the second communication device 2B. And the 2nd communication apparatus 2B which received data returns the delivery confirmation of the received data to the 1st communication apparatus 1B.

When the data delivery confirmation is transmitted to the delivery confirmation receiving unit 106 (Yes in Step S211), the delivery confirmation receiving unit 106 receives the delivery confirmation from the second communication device 2B (Step S212). The delivery confirmation receiving unit 106 transmits the time when the delivery confirmation is received to the determination unit 107. When the data delivery confirmation is not transmitted to the delivery confirmation receiving unit 106 (No in step S211), the communication control device 3B next performs the operation of step S213.

As described above, the determination unit 107 stores the time when the delivery confirmation receiving unit 106 last received the delivery confirmation. For example, the determination unit 107 may specify the time that has elapsed since the time when the delivery confirmation receiving unit 106 last received the delivery confirmation. And the determination part 107 should just compare the time which passed since the time when the delivery confirmation receiving part 106 received the delivery confirmation last, and a predetermined threshold value. When the time elapsed from the time when the delivery confirmation receiving unit 106 last received the delivery confirmation exceeds the threshold, the determination unit 107 may determine that the reception interval of the delivery confirmation exceeds the threshold. When the time elapsed from the time when the delivery confirmation receiving unit 106 last received the delivery confirmation does not exceed the threshold, the determination unit 107 may determine that the delivery confirmation reception interval does not exceed the threshold. When the determination unit 107 receives a delivery confirmation newly received from the delivery confirmation reception unit 106, the determination unit 107 receives the delivery confirmation, which is the difference between the time when the delivery confirmation is received and the stored time when the delivery confirmation is received. The interval may be derived. The determination unit 107 may determine whether the reception interval of the derived delivery confirmation exceeds a predetermined threshold value.

If the reception interval of the delivery confirmation does not exceed the predetermined threshold (No in step S213), the communication control device 3B next performs the operation of step S211. The delivery confirmation receiving unit 106 waits until the next delivery confirmation is transmitted.

When the reception interval of the delivery confirmation exceeds a predetermined threshold (Yes in Step S213), the determination unit 107 determines that a communication path temporary interruption has occurred (Step S214).

When it is determined that the communication path is temporarily interrupted, the changing unit 103 sets the detection period as described above. Then, the changing unit 103 determines whether or not switching of the communication path is detected within the detection period (step S215). For example, when the switching reception unit 108 receives a switching notification within the detection period, the changing unit 103 may determine that switching of the communication path has been detected within the detection period. For example, when the switching reception unit 108 does not receive the switching notification within the detection period, the changing unit 103 may determine that the switching of the communication path has not been detected within the detection period.

If the switching of the communication path is not detected within the detection period (No in step S215), the communication control device 3B next performs, for example, the operation of step S211.

When the switching of the communication path is detected within the detection period (Yes in step S215), the changing unit 103 changes the transmission connection as in the first embodiment (step S216).

This embodiment has the same effects as those of the first embodiment even when the second communication device 2B that receives data cannot determine whether or not communication is temporarily interrupted.

The reason is that the delivery confirmation transmission unit 204 transmits a delivery confirmation to the first communication device 1B in response to the data reception by the data reception unit 201. This is because the changing unit 103 determines whether or not a communication interruption has occurred based on the reception confirmation reception interval transmitted by the delivery confirmation transmitting unit 204.

This embodiment further has the same effect as the first embodiment even when the first communication device 1B that transmits data cannot detect the completion of the switching of the communication path.

The reason is that, when the switching detection unit 205 included in the second communication device 2B that receives data detects completion of switching of the communication path, the switching transmission unit 206 transmits a switching notification to the first communication device 1B. Because. Then, the change unit 103 determines that the communication path has been switched within the detection period when the switching reception unit 108 receives the switching notification within the detection period.

<Modification>
In the first to third embodiments, the switching detection unit 205 may be included in a switching detection device that is not illustrated in FIGS. 1 and 4. In the first and second embodiments, the switch detection unit 205 of the switch detection device may transmit a switch notification to the first communication device 1. In that case, the communication control apparatus 3 should just further include the switch receiving part 108 similarly to the communication control apparatus 3B of 3rd Embodiment. In the third embodiment, the switch detection unit 205 of the switch detection device may transmit a switch notification to the first communication device 1B.

In the first and second embodiments, the communication control device 3 is included in the first communication device 1. However, the communication control device 3 may be included in the second communication device 2. Alternatively, some of the components of the communication control device 3 may be included in the first communication device 1. And the component of the communication control apparatus 3 except the component contained in the 1st communication apparatus 1 may be contained in the 2nd communication apparatus 2. FIG.

Similarly, in the third embodiment, the communication control device 3B is included in the first communication device 1B. However, the communication control device 3B may be included in the second communication device 2B. Alternatively, some of the components of the communication control device 3B may be included in the first communication device 1B. And the component of the communication control apparatus 3B except the component contained in the 1st communication apparatus 1B may be contained in the 2nd communication apparatus 2B.

In the first embodiment, for example, the second communication device 2 may include the management unit 102 and the change unit 103 instead of the first communication device 1. In that case, the notification transmission unit 203 and the notification reception unit 104 are not necessary. And the 1st communication apparatus 1 should just contain the below-mentioned switching transmission part 109. FIG. And the 2nd communication apparatus 2 should just contain the switching receiving part 207 mentioned later. When the switching detection unit 105 detects completion of switching of the communication path, the switching transmission unit 109 transmits a switching notification indicating that the switching of the communication path is completed. The switch receiving unit 207 receives the switch notification transmitted by the switch transmitting unit 109. The change unit 103 included in the second communication device 2 newly creates a transmission connection when the switch transmission unit 109 receives a switch notification within the detection period set in the same manner as the change unit 103 of the first embodiment. Decide which connection to use. The second communication device 2 may further include a change instruction unit 208 that transmits an instruction to use the determined transmission connection for transmission to the first communication device 1. The data transmission unit 101 may change the transmission connection in accordance with the instruction received from the change instruction unit 208.

FIG. 7 is a block diagram illustrating an example of a configuration of a communication system 10A according to a modification of the first embodiment. In the example shown in FIG. 7, not the first communication device 1A but the second communication device 2A includes the communication control device 3A.

In the present modification, the first communication device 1A includes a data transmission unit 101, a switching detection unit 105, and a switching transmission unit 109. The second communication device 2A includes a data receiving unit 201 and a communication control device 3A. The communication control device 3A includes a management unit 102, a change unit 103, a determination unit 202, a switching reception unit 207, and a change instruction unit 208.

Further, in the first and second embodiments, the notification transmission unit 203 may transmit the temporary interruption notification a plurality of times within a predetermined transmission period instead of once. The transmission period may be a fixed period determined in advance. The transmission period may be a period until the data receiving unit 201 receives data after the determining unit 202 determines that a communication path temporary interruption has occurred. The transmission period is a statistical amount derived from a round trip delay time between the first communication device 1 and the second communication device 2 measured in advance or from the round trip delay time measured in the past. May be. The statistic is, for example, an average value, an intermediate value, or a median value. When the notification transmission unit 203 transmits the temporary disconnection notification a plurality of times, the notification transmission unit 203 may include an identifier that identifies the determination of the occurrence of the communication path temporary disconnection based on the temporary disconnection notification. .

In the third embodiment, for example, when delivery confirmation is performed in a lower-layer communication protocol among communication protocols used for communication, the delivery confirmation receiving unit 106 detects delivery confirmation based on the lower-layer communication protocol. May be. Alternatively, the first communication device 1B may not include the delivery confirmation receiving unit 106. The second communication device 2 may not include the delivery confirmation transmission unit 204. And the 1st communication apparatus 1 may contain the delivery confirmation part which detects the delivery confirmation in the lower layer communication protocol in which delivery confirmation is performed. TCP is an example of a communication protocol in which delivery confirmation is performed as described above.

<First implementation example>
Next, a first implementation example, which is an implementation example based on the first embodiment, will be described.

In this implementation example, the first communication device 1 and the second communication device 2 are communication terminals having a central processing unit, a memory, a storage device, and a network connection function.

The first communication device 1 is, for example, a portable communication terminal device connected via a base station to a mobile network that is communicably connected to the Internet. The first communication device 1 moves due to the movement of the user who holds the first communication device 1. As the first communication device 1 moves, the base station to which the first communication device 1 is connected is switched. The switching detection unit 105 detects switching of the base station to which the first communication device 1 is connected in the mobile network as switching of the communication path.

The second communication device 2 is, for example, a server disposed on the Internet. The second communication device 2 does not move. The second communication device 2 does not detect switching of the communication network.

The first communication device 1 and the second communication device 2 maintain two TCP connections that connect each other so that they can communicate with each other. Data transfer is directly performed between the first communication device 1 and the second communication device 2 using a TCP connection. In the following description of this modification, one of those two TCP connections is denoted as TCP connection A. Further, the other one of the two TCP connections is denoted as TCP connection B.

The first communication device 1 continues to transmit data to the second communication device 2 using the TCP connection A at intervals of, for example, 100 milliseconds. The first communication device 1 performs connection management processing in order to maintain a state in which a TCP connection B that is not used for data transmission is established. As the connection management process, the first communication device 1 transmits a keep alive message using a TCP connection, for example, every 300 milliseconds. The keep alive message is not data intended to exchange data between communication devices, but data intended to maintain a connection established state.

For example, the second communication device 2 is set to determine that a communication interruption, which is a state in which the communication path is temporarily disconnected, occurs when the data reception interval exceeds 5 seconds. For example, the data (n + 1) as the (n + 1) th data arrives at the second communication device 2 even after 5 seconds have elapsed since the second communication device 2 received the data n as the nth data. If not, the second communication device 2 determines that a communication path temporary interruption has occurred. If the second communication device 2 determines that a communication path temporary interruption has occurred, the second communication apparatus 2 transmits, for example, text data “Ichijidan” to the first communication apparatus 1 as a temporary interruption notification. The temporary disconnection notification is not limited to the text data described above. The temporary interruption notification may be data determined in advance.

The first communication device 1 is set to change the transmission connection when, for example, the difference between the time when the temporary disconnection notification is received and the time when the completion of the switching of the communication path is detected is within one second. Yes. For example, when the first communication device 1 detects the completion of the switching of the communication channel and receives a temporary disconnection notification 100 milliseconds after the detection, the first communication device 1 uses the TCP connection B instead of the TCP connection A as the transmission connection. Decide to do.

<Second implementation example>
Next, a second implementation example that is an implementation example based on the third embodiment will be described.

In this implementation example, as in the first implementation example, the first communication device 1B and the second communication device 2B are communication terminals having a central processing unit, a memory, a storage device, and a network connection function.

In the present implementation example, the first communication device 1B is a server arranged on the Internet. The first communication device 1B does not move. And the 1st communication apparatus 1B cannot detect switching of a communication path.

The second communication device 2B is a portable communication terminal device connected via a base station to a mobile network that is communicably connected to the Internet. As the second communication device 2B moves, the base station of the mobile network to which the second communication device 2B is connected is switched. The second communication device 2B detects the switching of the mobile network base station as the switching of the communication path.

For example, two TCP connections are maintained between the first communication device 1B and the second communication device 2B. Data transfer between the first communication device 1B and the second communication device 2B is performed directly via a TCP connection. Also in this implementation example, one of these two TCP connections is denoted as TCP connection A. The other of the two TCP connections is denoted as TCP connection B.

The first communication device 1B continues to transmit data to the second communication device 2B using the TCP connection A at predetermined intervals. In this implementation example, the predetermined interval is 100 milliseconds. When the second communication device 2B receives, for example, data 1 as the first data from the first communication device 1B, the second communication device 2B displays a delivery confirmation 1 indicating that the data 1 has been delivered to the first communication device 1B. Reply to The first communication device 1B receives the returned delivery confirmation 1. Similarly, between the first communication device 1B and the second communication device 2B, the data transmission and the delivery confirmation reply are performed for the data after the data 2 representing the second data.

The first communication device 1B performs connection management processing in order to maintain a state in which the TCP connection B that is not used for data transmission is established. As the connection management process, the first communication device 1B transmits a keep-alive message to the second communication device 2B using the TCP connection B every 300 milliseconds, for example.

The first communication device 1B receives the data (n + 1) th data (n + 1) transmitted in the same manner within a predetermined time after receiving the delivery confirmation n of the data n which is the nth data being transmitted ( If the delivery confirmation (n + 1) of (n + 1) does not arrive, it is determined that a communication path temporary interruption has occurred. The predetermined time is, for example, 5 seconds. In that case, if the first communication apparatus 1B has not received the delivery confirmation (n + 1) of the data (n + 1) even after 5 seconds have elapsed after receiving the delivery confirmation n of the data n, the communication path is temporarily interrupted. It is determined that it has occurred.

When the second communication device 2B detects completion of switching of the communication path, the second communication device 2B transmits a switching notification to the first communication device 1B. The switching notification may be, for example, text data such as “Tsushirinkokire”. The switching notification may be data determined in advance.

The first communication device 1B changes the transmission connection when, for example, the difference between the time when it is determined that the communication path is temporarily interrupted and the time when the switching notification is received is within a predetermined time. The predetermined time is, for example, 1 second. In this case, for example, when the first communication device 1B receives the switching notification 100 milliseconds after determining that the communication path temporary interruption has occurred, the first communication device 1B changes the transmission connection. Of the two TCP connections, the first communication device 1B determines TCP connection B that is not a transmission connection as a new transmission connection. That is, the first communication device 1B determines to use the TCP connection B in order to transmit data.

<Fourth Embodiment>
Next, a fourth embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 8 is a diagram illustrating an example of the configuration of the communication control device 3C according to the present embodiment.

Referring to FIG. 8, the communication control device 3 </ b> C of the present embodiment includes a management unit 102 and a change unit 103. The management unit 102 maintains a plurality of connections to the transmission destination device. In addition to receiving a temporary disconnection notification from the determination unit 202, the changing unit 103 receives a switching notification from the switching detection unit 105 within a predetermined period based on the temporary disconnection notification. Select a new selected connection from the connections. Then, the change unit 103 transmits the selected connection identifier to the data transmission unit 101. The determination unit 202 detects a temporary interruption that is a state where communication with the transmission destination device performed by the data transmission unit 101 via a selected connection selected from a plurality of connections is interrupted, and responds to detecting the temporary interruption Send a suspension notice. The switch detection unit 105 detects the switching of the communication path between the data transmission unit 101 and the transmission destination device, and transmits a switch notification when the completion of the switch is detected.

The communication apparatus according to the embodiment of the present invention can be realized by a computer and a program for controlling the computer, dedicated hardware, or a combination of a program for controlling the computer and the computer and dedicated hardware. The communication device according to the embodiment of the present invention includes a first communication device 1, a first communication device 1A, a first communication device 1B, a second communication device 2, a second communication device 2A, and a second communication. The device 2B, the communication control device 3, the communication control device 3A, the communication control device 3B, and the communication control device 3C.

FIG. 9 is a diagram illustrating an example of a configuration of a computer 1000 that can realize the communication apparatus according to the embodiment of the present invention. Referring to FIG. 9, a computer 1000 includes a processor 1001, a memory 1002, a storage device 1003, and an I / O (Input / Output) interface 1004. The computer 1000 can access the recording medium 1005. The memory 1002 and the storage device 1003 are storage devices such as a RAM (Random Access Memory) and a hard disk, for example. The recording medium 1005 is, for example, a storage device such as a RAM or a hard disk, a ROM (Read Only Memory), or a portable recording medium. The storage device 1003 may be the recording medium 1005. The processor 1001 can read and write data and programs from and to the memory 1002 and the storage device 1003. The processor 1001 can access, for example, other devices via the I / O interface 1004. The processor 1001 can access the recording medium 1005. The recording medium 1005 stores a program that causes the computer 1000 to operate as one of the communication apparatuses according to the embodiment of the present invention.

The processor 1001 loads a program stored in the recording medium 1005 to cause the computer 1000 to operate as one of the communication apparatuses according to the embodiment of the present invention. Then, when the processor 1001 executes the program loaded in the memory 1002, the computer 1000 operates as one of the communication apparatuses according to the embodiment of the present invention.

The units included in the following first group include, for example, a dedicated program that can be read from a recording medium 1005 that stores the program into the memory 1002 and that can realize the function of each unit, and a processor 1001 that executes the program. Can be realized. The units included in the following second group include, for example, a dedicated program that can be read from a recording medium 1005 that stores the program into the memory 1002 and that can realize the function of each unit, and a processor 1001 that executes the program. Can be realized. The first group includes a data transmission unit 101, a management unit 102, a change unit 103, a notification reception unit 104, a switching detection unit 105, a delivery confirmation reception unit 106, a determination unit 107, a switching reception unit 108, and a switching transmission unit 109. It is. The second group includes a data reception unit 201, a determination unit 202, a notification transmission unit 203, a delivery confirmation transmission unit 204, a switching detection unit 205, a switching transmission unit 206, a switching reception unit 207, and a change instruction unit 208.

Alternatively, a part or all of the parts included in the first group and the part included in the second group can be realized by a dedicated circuit that realizes the function of each part.

The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

Further, a part or all of the above embodiment can be described as in the following supplementary notes, but is not limited thereto.

(Appendix 1)
Management means for maintaining a plurality of connections to the destination device;
A temporary disconnection is detected in response to detecting a temporary disconnection in a state where communication with the transmission destination device performed by the data transmission unit via the selected connection selected from the plurality of connections is interrupted. In addition to receiving the temporary suspension notification from the determination means for transmitting
Within a predetermined period based on the temporary disconnection notification from the switching detection unit that detects switching of the communication path between the data transmission unit and the transmission destination device and transmits a switching notification when the completion of the switching is detected. If the switch notification is received on
Changing means for selecting a new selected connection from the plurality of connections other than the selected connection, and transmitting an identifier of the selected selected connection to the data transmitting means;
A communication control device comprising:

(Appendix 2)
The data transmission means transmits the data in association with a transmission time of the data,
The determination means transmits the transmission time associated with the data transmitted last before the occurrence of the temporary disconnection in association with the temporary disconnection notification,
The communication control device according to claim 1, wherein the changing unit sets a transmission time associated with the temporary disconnection notification to a start time of the predetermined period.

(Appendix 3)
The communication control device according to

claim

1 or 2, wherein the determination unit detects the temporary disconnection based on a time elapsed since the transmission destination device last received data from the data transmission unit.

(Appendix 4)
The data transmission means transmits the data at a predetermined interval,
The communication control apparatus according to any one of appendices 1 to 3, wherein the determination unit determines the occurrence of the temporary disconnection when a magnitude of a deviation of the interval for receiving the data from the predetermined interval exceeds a predetermined threshold.

(Appendix 5)
The start time of the predetermined period is a time that is a first predetermined time before a fixed time that is a time based on the temporary disconnection notification, or a last transmission time of the data before the occurrence of the temporary disconnection,
The communication control according to any one of appendices 1 to 4, wherein an end time of the predetermined period is a time after a second predetermined time from a fixed time that is a time based on the temporary suspension notification, or a reception time of the switching notification. apparatus.

(Appendix 6)
A transmission device including the data transmission means;
The destination device including data receiving means for notifying the determination means of reception of the data in response to receiving the data;
The communication control device according to any one of appendices 1 to 5,
A communication system including:

(Appendix 7)
The transmission device further includes the switching detection means and the communication control device,
The transmission destination device further includes the determination unit.
The communication system according to attachment 6.

(Appendix 8)
The transmission destination device further includes a confirmation transmission unit that transmits a delivery confirmation indicating that the data reception unit has received the data, and the switching detection unit,
The transmission device further includes a confirmation reception unit that notifies the determination unit of the reception time of the delivery confirmation as the reception time of the data in response to receiving the delivery confirmation, and the determination unit.
The communication system according to attachment 6.

(Appendix 9)
Maintain multiple connections to the destination device,
A temporary disconnection is detected in response to detecting a temporary disconnection in a state where communication with the transmission destination device performed by the data transmission unit via the selected connection selected from the plurality of connections is interrupted. In addition to receiving the temporary suspension notification from the determination means for transmitting
Within a predetermined period based on the temporary disconnection notification from the switching detection unit that detects switching of the communication path between the data transmission unit and the transmission destination device and transmits a switching notification when the completion of the switching is detected. If the switch notification is received on
A communication control method for selecting a new selected connection from the plurality of connections other than the selected connection and transmitting an identifier of the selected selected connection to the data transmitting means.

(Appendix 10)
Transmitting the data in association with the transmission time of the data,
A transmission time associated with the data transmitted last before the occurrence of the suspension is transmitted in association with the suspension notification;
The communication control method according to claim 9, wherein a transmission time associated with the temporary suspension notification is set to a start time of the predetermined period.

(Appendix 11)
The communication control method according to appendix 9 or 10, wherein the temporary disconnection is detected based on a time elapsed since the transmission destination device last received data from the data transmission unit.

(Appendix 12)
Sending the data at predetermined intervals,
The communication control method according to any one of appendices 9 to 11, wherein the occurrence of the temporary interruption is determined when the magnitude of deviation of the interval for receiving the data from the predetermined interval exceeds a predetermined threshold.

(Appendix 13)
The start time of the predetermined period is a time that is a first predetermined time before a fixed time that is a time based on the temporary disconnection notification, or a last transmission time of the data before the occurrence of the temporary disconnection,
The communication control according to any one of appendices 9 to 12, wherein the end time of the predetermined period is a time that is a second predetermined time after a fixed time that is a time based on the temporary suspension notification, or a reception time of the switching notification. Method.

(Appendix 14)
Computer
Management means for maintaining a plurality of connections to the destination device;
A temporary disconnection is detected in response to detecting a temporary disconnection in a state where communication with the transmission destination device performed by the data transmission unit via the selected connection selected from the plurality of connections is interrupted. In addition to receiving the temporary suspension notification from the determination means for transmitting
Within a predetermined period based on the temporary disconnection notification from the switching detection unit that detects switching of the communication path between the data transmission unit and the transmission destination device and transmits a switching notification when the completion of the switching is detected. If the switch notification is received on
Changing means for selecting a new selected connection from the plurality of connections other than the selected connection, and transmitting an identifier of the selected selected connection to the data transmitting means;
Communication control program to be operated.

(Appendix 15)
Computer
The data transmission means for transmitting the data in association with the transmission time of the data;
The determination means for transmitting the transmission time associated with the data transmitted last before the occurrence of the suspension in association with the suspension notification;
The changing means for setting a transmission time associated with the suspension notice to a start time of the predetermined period;
The communication control program according to appendix 14, which is operated as described above.

(Appendix 16)
Computer
The determination means for detecting the temporary disconnection based on a time elapsed since the transmission destination device last received data from the data transmission means;
The communication control program according to appendix 14 or 15, which is operated as described above.

(Appendix 17)
Computer
The data transmission means for transmitting the data at a predetermined interval;
The determination means for determining the occurrence of the temporary disconnection when the magnitude of deviation of the interval for receiving the data from the predetermined interval exceeds a predetermined threshold;
The communication control program according to any one of appendices 14 to 16, which is operated as described above.

(Appendix 18)
The start time of the predetermined period is a time that is a first predetermined time before a fixed time that is a time based on the temporary disconnection notification, or a last transmission time of the data before the occurrence of the temporary disconnection,
The communication control according to any one of appendices 14 to 17, wherein the end time of the predetermined period is a time after a second predetermined time from a fixed time that is a time based on the temporary suspension notification, or a reception time of the switching notification. program.

This application claims priority based on Japanese Patent Application No. 2014-0081114 filed on April 10, 2014, the entire disclosure of which is incorporated herein.

The present invention can be applied to systems that are severe in communication delay, such as voice and interactive services.

DESCRIPTION OF SYMBOLS 1 1st communication apparatus 1A 1st communication apparatus 1B 1st communication apparatus 2 2nd communication apparatus 2A 2nd communication apparatus 2B 2nd communication apparatus 3 Communication control apparatus 3A Communication control apparatus 3B Communication control apparatus 3C Communication Control device 10 Communication system 10A Communication system 10B Communication system 101 Data transmission unit 102 Management unit 103 Change unit 104 Notification reception unit 105 Switching detection unit 106 Delivery confirmation reception unit 107 Determination unit 108 Switching reception unit 109 Switching transmission unit 201 Data reception unit 202 Determination unit 203 Notification transmission unit 204 Delivery confirmation transmission unit 205 Switching detection unit 206 Switching transmission unit 207 Switching reception unit 208 Change instruction unit 1000 Computer 1001 Processor 1002 Memory 1003 Storage device 1004 I / O interface 1005 Recording Body

Claims

Management means for maintaining a plurality of connections to the destination device;
A temporary disconnection is detected in response to detecting a temporary disconnection in a state where communication with the transmission destination device performed by the data transmission unit via the selected connection selected from the plurality of connections is interrupted. In addition to receiving the temporary suspension notification from the determination means for transmitting
Within a predetermined period based on the temporary disconnection notification from the switching detection unit that detects switching of the communication path between the data transmission unit and the transmission destination device and transmits a switching notification when the completion of the switching is detected. If the switch notification is received on
Changing means for selecting a new selected connection from the plurality of connections other than the selected connection, and transmitting an identifier of the selected selected connection to the data transmitting means;
A communication control device comprising:
The data transmission means transmits the data in association with a transmission time of the data,
The determination means transmits the transmission time associated with the data transmitted last before the occurrence of the temporary disconnection in association with the temporary disconnection notification,
The communication control apparatus according to claim 1, wherein the changing unit sets a transmission time associated with the temporary suspension notification as a start time of the predetermined period.
The communication control device according to claim 1, wherein the determination unit detects the temporary disconnection based on a time elapsed since the transmission destination device last received data from the data transmission unit.
The data transmission means transmits the data at a predetermined interval,
The communication control device according to any one of claims 1 to 3, wherein the determination unit determines the occurrence of the temporary disconnection when a magnitude of a deviation of the interval of receiving the data from the predetermined interval exceeds a predetermined threshold.
The start time of the predetermined period is a time that is a first predetermined time before a fixed time that is a time based on the temporary disconnection notification, or a last transmission time of the data before the occurrence of the temporary disconnection,
5. The communication according to claim 1, wherein the end time of the predetermined period is a time after a second predetermined time from a fixed time that is a time based on the temporary suspension notification, or a reception time of the switching notification. Control device.
A transmission device including the data transmission means;
The destination device including data receiving means for notifying the determination means of reception of the data in response to receiving the data;
A communication control device according to any one of claims 1 to 5;
A communication system including:
The transmission device further includes the switching detection means and the communication control device,
The transmission destination device further includes the determination unit.
The communication system according to claim 6.
The transmission destination device further includes a confirmation transmission unit that transmits a delivery confirmation indicating that the data reception unit has received the data, and the switching detection unit,
The transmission device further includes a confirmation reception unit that notifies the determination unit of the reception time of the delivery confirmation as the reception time of the data in response to receiving the delivery confirmation, and the determination unit.
The communication system according to claim 6.
Maintain multiple connections to the destination device,
A temporary disconnection is detected in response to detecting a temporary disconnection in a state where communication with the transmission destination device performed by the data transmission unit via the selected connection selected from the plurality of connections is interrupted. In addition to receiving the temporary suspension notification from the determination means for transmitting
Within a predetermined period based on the temporary disconnection notification from the switching detection unit that detects switching of the communication path between the data transmission unit and the transmission destination device and transmits a switching notification when the completion of the switching is detected. If the switch notification is received on
A communication control method for selecting a new selected connection from the plurality of connections other than the selected connection and transmitting an identifier of the selected selected connection to the data transmitting means.
Computer
Management means for maintaining a plurality of connections to the destination device;
A temporary disconnection is detected in response to detecting a temporary disconnection in a state where communication with the transmission destination device performed by the data transmission unit via the selected connection selected from the plurality of connections is interrupted. In addition to receiving the temporary suspension notification from the determination means for transmitting
Within a predetermined period based on the temporary disconnection notification from the switching detection unit that detects switching of the communication path between the data transmission unit and the transmission destination device and transmits a switching notification when the completion of the switching is detected. If the switch notification is received on
Changing means for selecting a new selected connection from the plurality of connections other than the selected connection, and transmitting an identifier of the selected selected connection to the data transmitting means;
A recording medium for storing a communication control program to be operated.