JP2000216825A - Ip multicast delivery acknowledgement communication control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute delivery acknowledgement of transmission data and resending of data and to certify the transmitting order of data in the case of simultaneously transmitting data such as command information to plural commanding destinations. SOLUTION: A transmitter 1-1 simultaneously transmits data such as command information to plural receivers 1-2 by an IP multicast communicating procedure. Each receiver 1-2 receiving data by the IP multicast communicating procedure sends the message of delivery acknowledgement back to the transmitter 1-1 by a TCP/IP communicating procedure. The transmitter 1-1 resends data to the receiver from which the message of delivery acknowledgement is not sent back by the TCP/IP communicating means. In addition, the transmitter 1-1 adds a sequence number to transmission data and transmits it, and the receivers 1-2 are provided with a function of rearranging received data based on the sequence number.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for transmitting data such as command information to a plurality of command destinations at the same time. Related to control system.

In a prefectural disaster prevention system or the like, a warning from the Meteorological Agency or a report of exceeding a standard rainfall value of a rainfall sensor installed in each place is received by a disaster prevention center installed in the prefectural government or the like, and the disaster prevention center receives a command line via a command line. To send command information, such as warning announcements, to civil engineering offices, municipal offices, etc. in various places.

A civil engineering office, a municipal office, or the like to which the command information is transmitted returns a delivery confirmation message indicating that the command information has been received to the disaster prevention center via the command line, and the disaster prevention center transmits the command information. Despite the fact that the delivery confirmation message is not returned,
A system is employed in which the command information is retransmitted so that important transmission data such as the command information is not missed.

[0004] In recent years, communication techniques have changed from analog communication using a disaster prevention radio or a public line network to digital communication using a digital network as means for transmitting command information or the like. A large amount of data can be communicated.

[0005] Further, the command information is based on simple transmission signals such as voice, text, facsimile, etc., and is also complicated and diversified, such as a voice synthesis file and image information from an on-site monitoring television camera (ITV camera). It can be transmitted as multimedia information.

That is, a large amount of information can be divided into a plurality of data and transmitted in a short time by using a high-speed digital circuit network, and can be simultaneously transmitted to many command destinations simultaneously. In order to transmit the data, a communication procedure of the delivery confirmation and retransmission is required.

[0007]

2. Description of the Related Art Communication methods for command information in a prefectural disaster prevention system or the like can be roughly divided into two types, one by one communication and one by N communication. FIG. 9 shows a conventional one-to-one.
It is explanatory drawing of communication of the command information by communication.

The transmitting device 9-1 for commands provided in the disaster prevention center and the receiving devices 9-21 ₁ to 9-2 _i to each command destination.
9-2 _m and 9-2 _n perform 1-to-1 communication, respectively.
Transmission of data such as command information and acknowledgment of the transmission are performed by a transmission control procedure of one-to-one communication.

As a transmission control procedure of the one-to-one communication, for example, an HDLC-ABM (High-Level Data Link Control Procedure Asynchronous Balanced Mode) procedure or the like is used to transmit data and confirm delivery.

FIG. 10 is a diagram for explaining communication of command information by conventional one-to-N communication. The command transmitting device 10-1 includes:
Receiving device 10-2 _{1 to} 10-2 _{i to} 10-2 of each command destination
_m, to 10-2 _n, data such as command information by l to N communication broadcasts. The broadcast of this one-to-N communication does not have a delivery confirmation function.

[0011] Therefore, each receiver of the command destination 10-2 ₁
10-2 _i , 10-2 _m , and 10-2 _n sequentially return a delivery confirmation message by another communication means in accordance with a predetermined time delay difference, and the transmission device 10-1 returns the message. The received acknowledgment message is received and acknowledgment is performed.

[0012]

In the communication of command information by the above-mentioned one-to-one communication, a delivery confirmation message is returned immediately after the transmission of the command data, so that the delivery confirmation is reliably performed. Has a drawback that it takes a long time to finish sending command information to all command destinations as the number of receiving devices increases because communication processing of command information is performed sequentially for each receiving device. .

In the communication of command information by the above-mentioned 1-to-N communication, the command information can be transmitted to all command destinations by 1 times of broadcast communication. Is transmitted by broadcast, so that resources are occupied by invalid data.

Further, in order to perform the delivery confirmation, it is necessary to prepare a certain waiting time for returning the delivery confirmation message in each receiving device in advance. The following information cannot be communicated between the transmitting device and each receiving device.

According to the present invention, a large amount of command information divided into a plurality of data can be transmitted to a plurality of destinations in a short time, and delivery confirmation and data retransmission can be performed.
It is another object of the present invention to provide an IP multicast acknowledgment communication control system capable of managing and processing data according to a transmission order.

[0016]

An IP multicast delivery confirmation communication control system according to the present invention comprises: (1) a system for performing simultaneous communication from a transmitting device to a plurality of receiving devices by an IP multicast communication procedure; The receiving device that has received the data according to the communication procedure includes a unit that returns a delivery confirmation message to the transmitting device according to the TCP / IP communication procedure.

(2) The transmitting device that has performed the simultaneous communication according to the IP multicast communication procedure transmits a TCP / I message to the receiving device to which a delivery confirmation message is not returned.
A means for retransmitting the transmission data by the P communication procedure is provided.

[0018] (3) The transmitting device that has performed the simultaneous communication according to the IP multicast communication procedure cancels the retransmission of the transmission data after a lapse of a preset survival time to the receiving device that does not return a delivery confirmation message. It is provided with.

[0019] (4) The transmitting device includes means for adding a sequence number to a plurality of data to be broadcast simultaneously in sequence by an IP multicast communication procedure and transmitting the data, and the receiving device comprises: It has means for receiving data in the order of the numbers.

(5) The transmitting device transmits data to be broadcast simultaneously by an IP multicast communication procedure.
Means for transmitting with the information indicating the necessity of the delivery confirmation; andthe receiving device comprises means for returning the message of the delivery confirmation based on the information indicating the need for the delivery confirmation of the received data. It is a thing.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a configuration diagram of an IP multicast delivery confirmation communication control system of the present invention. In the figure,
1-1 is a transmitting device, 1-2 is a receiving device, 1-3 is a router, and 1-4 is a network.

The transmitting device 1-1 has a LAN (Local Area N).
etwork), is connected to the router 1-3, transmits data such as command information to the receiving device 1-2 via the router 1-3 and the network 1-4, and confirms delivery from the receiving device 1-2. Has a function of resending data such as command information when the message is not returned.

The receiving device 1-2 is connected to the router 1-3 via a LAN.
And the transmission device 1-1 to the router 1-3,
Data such as command information transmitted via the network 1-4 is received, and based on the data, the command information or the like is displayed on a display device or an alarm is issued to a staff member at the command destination office or the like. The transmitting device 1 performs a processing operation of notifying command information and the like, and transmits a message for confirming delivery of data such as the command information.
Reply to -1.

Router 1-3 on transmitting device side and receiving device side
Are connected to a transmitting device and a receiving device via a LAN, are connected to each other via a network (WAN: Wide Area Network) 1-4 such as a public network or a private line network, and are connected to the LAN. Data such as command information issued from the transmission source is distributed to the transmission destination based on the IP address.

The IP address is the address of the destination and source of the IP datagram written in the header portion of the IP datagram, and its upper bits indicate the class of the address system. In the class D address system, The first four bits (1110) indicate multicasting, and the remaining 28 bits specify a particular multicast group.

When the IP address is an address designated by a multicast group, the apparatus has a function of copying and delivering data such as command information only to a plurality of destinations registered in the group.

The network 1-4 connects the routers 1-3 connected to the LAN to each other, and establishes a remote
N enables data communication between the transmitting device 1-1 and the receiving device 1-2 connected to the N.

FIG. 2 is a configuration diagram of a communication function in the transmitting device and the receiving device of the present invention. In the figure, 2-1 is an application unit, 2-2 is a communication control unit, 2-3 is an IP multicast communication unit, and 2-4 is a TCP / IP communication unit.

In the transmitting device, the application unit 2
-L determines creation of data such as command information, transmission destination of data such as command information, survival time of data such as command information, necessity of confirmation of transmission of transmission data, necessity of observance of transmission order, and the like. , A transmission request to the communication control unit 2-2.

The communication control unit 2-2 of the transmitting device transmits data such as command information requested to be transmitted from the application unit 2-1, receives a delivery confirmation message, retransmits data such as command information, and survives. Perform processing such as discarding data when the number is exceeded.

In the transmitting device, the IP multicast communication unit 2-3 recognizes the multicast group from the IP address of the data such as command information requested by the communication control unit 2-2 to transmit, and transmits the data such as command information. , To the receiving devices in the multicast group all at once.

In the transmitting device, the TCP / IP communication unit 2-4 has a TCP / I communication
P (Transmission Control Protocol / Internet Protoco
l) The communication according to the communication procedure (protocol) is performed, the message of the acknowledgment is received, and the data such as the command information for which the acknowledgment message was not received is retransmitted.

In the receiving device in the multicast group, the IP multicast communication unit 2-3 receives the data such as the command information broadcast at the same time, and notifies the communication control unit 2-2 of the received data.

TCP / IP communication section 2 in receiving apparatus
4 performs communication according to the TCP / IP communication procedure, and the receiving device that has received the data such as the command information transmits a delivery confirmation message to the transmitting device by the TCP / IP communication unit 2-4. It has a function of receiving data such as command information retransmitted from the transmitting device.

The communication control section 2-2 of the receiving device sends a delivery confirmation message for the received data such as command information to the TCP / IP communication section 2-4, and transmits the received data such as the command information. The order of the order is rearranged, and further, processing such as discarding data that has exceeded the survival time is performed.
Data such as command information for normal reception is transmitted to the application unit 2-1.

Application section 2- in the receiving device
1 performs various processes such as display of command information and the like and alarm issuance in accordance with data such as command information and the like of normal reception processed by the communication control unit 2-2.

When transmitting command information from the transmitting device to the receiving device, the command information is divided into a plurality of command data and transmitted, and the receiving device processes the command data in accordance with the transmission order from the transmitting device. If you need to do that,
A job start message is sent before sending the command data, and after sending the command data,
Send a job end message.

FIG. 3 shows an IP multicast according to the present invention.
It is explanatory drawing of transmission of command information. App of transmitting device 3-1
Application section, communication control section and IP multicast
The job start message and the command data
Data and job end message command information
Receiving device 3-2 in cast group₁~ 3-2_i~ 3
-2_mSend all at once. IP multicast group
Receiving device 3-2 other than _nCommand information is sent to
Not.

Receiving device 3-2 having received the command information
Each of _{1 to} 3-2 _{i to} 3-2 _m returns a received message and a message for confirming delivery of each data to the transmitting device 3-1 by the TCP / IP communication unit.

FIG. 4 is an explanatory diagram of retransmission of command information by TCP / IP according to the present invention. In FIG.
1 and the receiving device 3-2 ₁ ~3-2 _i ~3-2 _m is 3
It is similar to the one shown in.

[0041] In FIG 4, when acknowledgment messages for instruction information transmitted by the IP multicast from the transmitter 3-1, for example, which has not been returned from the receiving device 3-2 _i, the reception device 3-2 Only for _i , the command information is retransmitted by the TCP / IP communication procedure.

As described above, according to the IP multicast communication procedure, the command information is transmitted to a plurality of receiving devices at once, so that a large amount of command information can be transmitted to the receiving device of the command destination in a short time.

The transmitting device and each receiving device are TCP
/ IP communication procedure, and confirms the delivery of the command information by the TCP / IP communication procedure, and retransmits the command information for the command information for which the delivery is not confirmed by the TCP / IP.
This is done according to the communication procedure.

Further, the transmitting device transmits a job start message, command data added with a sequence number and a job end message to each receiving device, and the receiving device rearranges the data based on the sequence number to transmit. The command data can be received by the receiving device in the transmission order of the command data in the device.

For this reason, even if a reverse occurs between the transmission order and the reception order due to a delay due to data retransmission or the like, the receiving device processes the command data in the transmission order and guarantees the order of the command processing. can do.

FIG. 5 is an explanatory diagram of a communication route of command information by IP multicast according to the present invention. The application unit 5-11 of the transmission device (command device) 5-10 transmits command information including a job start message, command data 1 to N, and a job end message to the communication control unit 5-12.
To send to.

The communication control unit 5-12 sends command information to the IP multicast communication unit 5-13. The IP multicast communication unit 5-13 sends the command information to the receiving device 5-20.
To the IP multicast communication unit 5-23.

The IP multicast communication unit 5-23 of the receiving device 5-20 transmits the received command information to the communication control unit 5-2.
Hand over to 2. The communication control unit 5-22 passes the command information to the application unit 5-21, and transmits the received job start message, the command data 1 to N, and the delivery confirmation message of the job end message to the TCP /
It is sent to IP communication section 5-24.

The TCP / IP communication unit 5 of the receiving device 5-20
-24 transmits a command information delivery confirmation message to the TCP / IP communication unit 5-14 of the transmission device 5-10.
The TCP / IP communication section 5-14 notifies the communication control section 5-12 of a command information delivery confirmation message.

FIG. 6 is a diagram showing an example of a command information transmission request in the transmission device of the present invention. (A), (b) of FIG.
Shows a transmission request application (command information) created by the application unit of the transmission device, (a) shows a certain application A, (b) shows another application B
Is exemplarily shown.

As shown in FIG. 5A, a job start message, command data Al,
A request for transmitting the command data A2 and the job end message is sequentially generated. Further, as shown in FIG. 3B, a command is sent from another application B between the command data Al of the application A and the command data A2. It is assumed that a transmission request for the data Bl occurs.

The job start message of the application A includes information indicating that the job survival time is 60 seconds and the transmission destination is x and y. The command data Bl of the application B has the data survival time of 30 seconds. , And information indicating that the transmission destination is x.

FIG. 6C shows a job management table in the communication control unit of the transmission device. The illustrated job management table shows one created based on the transmission request example of the application A shown in FIG. 6A, and includes a job ID, a job lifetime, a transmission destination, a job status,
Holds job information including a sequence number and the like.

FIG. 7 is a diagram showing a retransmission data management table of the transmitting apparatus according to the present invention. The retransmission data management table is
FIG. 7A shows a retransmission data management table for the transmission destination x, and FIG. 7B shows a retransmission data management table for the transmission destination y in the communication control unit of the transmission device. .

The communication control unit of the transmitting device holds the data of the transmitted command information in the queuing memory in order to retransmit the data when the message of the delivery confirmation is not returned. The retransmission data management table contains the job number,
The information of the sequence number and the presence / absence of the next data is held in correspondence with the data of the command information.

The retransmission data management tables 7a-1 to 7a-5 for the transmission destination x and the retransmission data management tables 7b-1 to 7b-4 for the transmission destination y shown in FIG.
When a delivery confirmation message is returned in the table corresponding to the command information data, the message is deleted together with the command information data. However, in FIG. Describes the data management table.

FIG. 8 is a view showing a reception job management table of the receiving apparatus of the present invention. The reception job management table is
The communication control unit of the receiving device is created by receiving the job start message, and the reception job management table shown in the figure includes the transmission destination x and the transmission destination by the job start message of the transmission request of the application A shown in FIG. 7 shows a reception job management table created by the communication control unit of the receiving device of FIG.

The reception job management table is created for each job, and holds a job number (ID), job lifetime, job status, next sequence number, and saved data.
As the storage data, the job number, sequence number, and information on the presence / absence of the next data are held in correspondence with the data of the received instruction information.

Actually, the communication control unit of the receiving device returns a delivery confirmation message to the received data. If the sequence number is correct, the communication control unit does not store the received data in the queuing memory. The next sequence number is received,
The data in the queuing memory is sent to the application unit, and the stored data disappears. However, all the stored data is described for explanation of the transmission request example in FIG.

The operation flow of transmitting command information by IP multicast and confirming the delivery and retransmission of the command information according to the present invention will be described below with reference to FIGS. 6 to 8, taking the transmission request of the application shown in FIG. 6 as an example. .

(1) When transmitting a plurality of command data, the application unit of the transmitting apparatus receives the plurality of command data in the transmission order in the receiving apparatus, and if the command data needs to be processed, before transmitting the command data, A job start message is notified to the communication control unit together with the transmission destination and the job lifetime (see application A in FIG. 6A).

(2) The communication control unit notified of the job start searches for a free job number (ID), sets the searched free job number to “in use”, and sets the job information (transmission destination) notified from the application unit. , Job lifetime, etc.)
Is stored in the job management table (see the job management table in FIG. 6C).

(3) The communication control unit of the transmitting device notifies the application unit of the job number to be used for the subsequent data transmission, and also includes the job information such as the job number and the job lifetime in the receiving device of the transmission destination. A job start message is transmitted via the IP multicast communication unit.

(4) The communication control unit of the transmission device holds the transmitted job start message in the retransmission data management table, and waits for a delivery confirmation message (7 in FIG. 7).
a-1 and 7b-1).

(5) The receiving device notifies the communication control unit of the job start message received via the IP multicast communication unit.

(6) If the communication control unit of the receiving apparatus is the destination, the communication control unit creates job information from the received job start message in the reception job management table of the own apparatus (see FIG. 8). ).

(7) Further, the communication control unit of the receiving device notifies the application unit of the received job start message and transmits a job start message delivery confirmation message via the TCP / IP communication unit. Reply to device.

(8) In the receiving device for which the transmission destination is not specified, the received job start message is discarded.

(9) The communication control unit of the transmitting device, to which the message of the delivery confirmation has been returned via the TCP / IP communication unit,
The job start message is deleted from the retransmission data management table.

(10) The communication control unit of the transmitting device manages the wait for delivery confirmation, and sends the job start message to the TCP / IP communication unit for the receiving device that does not receive the delivery confirmation message of the job start message. Resend via.

(11) The communication control unit of the receiving device that has received the job start message retransmitted via the TCP / IP communication unit performs the reception job management of its own device similarly to the case where the communication control unit receives the job start message via the TCP / IP communication unit. Create job information from the received job start message in the table,
Similarly to (7), the application unit notifies the application unit that the job start message has been received, and returns a transmission confirmation message of the job start message to the transmitting device via the TCP / IP communication unit.

(12) Next, the application unit of the transmitting device requests the communication control unit to transmit command data. At this time, if the transmission destination has already been notified by the transmission request of the previous job start message, the job number is notified. Otherwise, the command data is transmitted together with the transmission destination, necessity of delivery confirmation, and the like. It is sent to the communication control unit (see FIGS. 6A and 6B).

(13) When the transmission is requested by designating the job number, the communication control unit of the transmission device searches the job information, adds 1 to the sequence number, and adds the transmission destination registered in the job information. And specify command data as IP
The broadcast is transmitted to the receiving device via the multicast communication unit.

(14) Then, the communication control unit of the transmitting device holds the transmitted command data in the retransmission data management table and waits for a delivery confirmation message (see 7a-2, 7a-2 in FIG. 7).
4 and 7b-2, 3).

(15) When the transmission is requested without specifying the job number, the communication control unit of the transmission device specifies the transmission destination notified together with the command data requested to be transmitted, and
The broadcast is transmitted to the receiving device via the IP multicast communication unit.

(16) If the received command data is transmission confirmation required, the communication control unit of the transmitting device stores the transmitted command data in the retransmission data management table and waits for a transmission confirmation message (FIG. 7). 7a-3).

(17) The communication control unit of the receiving device that has received the data via the IP multicast communication unit notifies the application unit of the received command data when the own device is the transmission destination. If the job number is specified, check whether the command data is received in the transmission order using the sequence number of the reception job management table of the own device. Is received by the communication control unit and is not notified to the application unit.

(18) The communication control unit of the receiving device transmits data such as transmission order command information to the IP multicast communication unit or the T
When the job information data is received from the CP / IP communication unit, the job information data held together with the received data is also notified to the application unit.

(19) When receiving data requested by designating a job number or receiving data for which transmission confirmation is required, the communication control unit of the receiving apparatus transmits a data transmission confirmation message. A reply is sent to the transmitting device via the TCP / IP communication unit.

(20) When the acknowledgment message is returned, the communication control unit of the transmitting device deletes the retransmission data from the retransmission data management table.

(21) The communication control unit of the transmitting device manages the delivery confirmation and sends the transmission request data to the receiving device to which the delivery confirmation message of the transmitted data has not been transmitted.
Retransmit via the CP / IP communication unit.

(22) The communication control unit of the receiving device that has received the retransmission data via the TCP / IP communication unit performs the above-described processes (17) to (19), similarly to the reception of the IP multicast communication unit.

(23) When the application unit of the transmitting device has notified the job start message, and completes a series of data transmission requests such as command information, the application unit notifies the communication control unit of the job end message.

(24) The communication control unit of the transmitting device notified of the job end message searches for the job information based on the job number, and transmits the job end message to the destination device of the job information by IP multicast. Broadcasting is performed via the communication unit, and a message indicating the end of the job is stored in the retransmission data management table (see 7a-5 and 7b-4 in FIG. 7).

(25) The communication control unit of the receiving device that has received the job end message via the IP multicast communication unit sends the job end message reception to the application unit when the destination device is designated. At the same time, a transmission confirmation message of a job end message is returned to the transmitting device via the TCP / IP communication unit. (26) At this time, the job status in the reception job management table is set to the end status.

(27) The communication control unit of the transmitting device, which has returned the delivery confirmation message via the TCP / IP communication unit, manages the delivery confirmation of the job completion message, and reads the job completion message from the retransmission data management table. Is deleted, and the job status in the job management table is set to the end status.

(28) For a receiving apparatus to which the message of confirming the delivery of the job end message has not been transmitted, the job end message is retransmitted via the TCP / IP communication unit.

(29) Upon receiving the job end message via the TCP / IP communication section, the communication control section
The processing of (25) and (26) is performed in the same manner as in the case of receiving via the P multicast communication unit.

In the above operation, the transmitting device:
When the command data transmission exceeds a predetermined data lifetime, the retransmission data is deleted from the retransmission data management table. When the job lifetime specified at the start of the job is exceeded, the job information is deleted, and the retransmission data of the job stored in the retransmission data management table of the destination device is deleted.

In the receiving apparatus, when the job life time is exceeded, the job information is deleted from the received job management table, and if there is stored received data, it is deleted.

[0091]

As described above, according to the present invention,
By transmitting data such as command information all at once using IP multicast communication, a large amount of data is transmitted in a short time, and when it is necessary to reliably transmit data such as command information to each destination. , The delivery is individually confirmed using the TCP / IP communication procedure, and if the delivery is not confirmed,
By retransmitting the data, it is possible to prevent loss of important transmission data such as command information.

When the data transmission order is important, data such as command information with a sequence number is transmitted between the job start and job end messages. By rearranging the data, the order of transmission is observed, and the order of command processing can be guaranteed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an IP multicast delivery confirmation communication control system of the present invention.

FIG. 2 is a configuration diagram of a communication function in a transmission device and a reception device of the present invention.

FIG. 3 is an explanatory diagram of transmission of command information by IP multicast according to the present invention.

FIG. 4 is an explanatory diagram of retransmission of command information by TCP / IP according to the present invention.

FIG. 5 is an explanatory diagram of a communication route of command information by IP multicast according to the present invention.

FIG. 6 is a diagram illustrating an example of a transmission request for command information in the transmission device of the present invention.

FIG. 7 is a diagram showing a retransmission data management table of the transmission device of the present invention.

FIG. 8 is a diagram showing a reception job management table of the reception device of the present invention.

FIG. 9 is an explanatory diagram of communication of command information by conventional one-to-one communication.

FIG. 10 is an explanatory diagram of communication of command information by conventional one-to-N communication.

[Explanation of symbols]

1-l, 3-1,5-10 transmitting apparatus 1-2,3-2 ₁ ~3-2 _n, 5-20 receiving device 1-3 router 1-4 Network 2-1,5-11,5- 21 Application section 2-2, 5-12, 5-22 Communication control section 2-3, 5-13, 5-23 IP multicast communication section 2-4, 5-14, 5-24 TCP / IP communication section

Claims (5)

[Claims] 1. A transmitting apparatus, comprising: a plurality of receiving apparatuses;
In a system for performing simultaneous communication according to an IP multicast communication procedure, a receiving apparatus receiving data according to the IP multicast communication procedure includes means for returning a delivery confirmation message to the transmitting apparatus according to a TCP / IP communication procedure. An IP multicast delivery confirmation communication control system, characterized in that: 2. A transmitting apparatus that has performed simultaneous communication according to the IP multicast communication procedure includes a unit that retransmits transmission data according to a TCP / IP communication procedure to a receiving apparatus to which a delivery confirmation message is not returned. The IP multicast delivery confirmation communication control system according to claim 1, wherein: 3. The transmitting apparatus which has performed simultaneous communication according to the IP multicast communication procedure has means for terminating retransmission of transmission data after a lapse of a preset survival time to a receiving apparatus to which a delivery confirmation message is not returned. 3. The communication control system according to claim 2, wherein: 4. The transmitting device further comprises means for attaching a sequence number to a plurality of data to be simultaneously broadcast in sequence by an IP multicast communication procedure and transmitting the data, and wherein the receiving device comprises: 2. A means for receiving data according to the following:
5. The IP multicast delivery confirmation communication control system according to any one of claims 1 to 4. 5. The transmitting apparatus further comprises means for transmitting, to the data to be broadcast simultaneously by an IP multicast communication procedure, with information indicating whether or not transmission confirmation is necessary, and wherein the receiving apparatus comprises: 5. The IP multicast acknowledgment communication control system according to claim 1, further comprising: means for sending back the acknowledgment message based on information indicating whether or not the acknowledgment is necessary.