KR101806143B1 - METHOD FOR PROVIDING PRoPHET ROUTING PROTOCOL USING RESTRICTION OF MESSAGE DUPLICATION, RECORDING MEDIUM, SYSTEM AND DEVICE FOR PERFORMING THE METHOD - Google Patents

Abstract

A PRoPHET routing protocol providing method using a message copy restriction according to the present invention comprises the steps of: exchanging a summary vector (SV) containing information of a node with a correspondent node when a node makes contact with each other; Confirming whether the message is overlapped with the counterpart node; Comparing the message delivery count (DupC) with the counterpart node and updating the message delivery count with a larger value if the message is duplicated; If the message is not duplicated, comparing the number of times its message is delivered with a threshold (DupC Threshold); Comparing the transmission prediction rate with the counterpart node if the number of times of message delivery is smaller than a threshold value; And delivering a message to the correspondent node when the message transmission prediction rate of the correspondent node is large. Accordingly, the performance of the existing PRoPHET protocol can be improved since the transmission of unnecessary duplicate messages can be appropriately reduced and the limited buffer capacity can be effectively used.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PRoPHET routing protocol providing method, and more particularly, to a PRoPHET routing protocol providing method using a message copy restriction, a recording medium, a system and a device for performing the PRoPHET routing protocol,

The present invention relates to a PRoPHET routing protocol providing method using a message copy restriction, a recording medium, a system, and an apparatus for performing the PRoPHET routing protocol. More particularly, the present invention relates to a PRoPHET routing protocol providing method, And to improve the performance of the PRoPHET protocol, which delivers the message to a node with a higher delivery prediction rate to the destination node when it contacts the other node.

In a delay tolerant network (DTN), where a communication path between a source node and a destination node is not guaranteed, a message node stores it in its own buffer, and an opportunistic store-carry-forward network in which messages are transmitted using a contact, and a disaster-free environment in which there is no infrastructure. Typical delay tolerant network protocols include Epidemic and PRoPHET.

The Epidemic protocol is a flooding-based protocol that attempts to increase the message delivery rate by rapidly spreading the message by copying the message to all nodes in contact. In the delay tolerant network research group (DTNRG) of the Internet Research Task Force (IRTF), the standardized probabilistic routing protocol for intermittently connected networks (PRoPHET) defines delivery predictability based on contact information with other nodes , Which is a protocol for copying and delivering a message to a node having a higher delivery predictive rate as a destination node of a message in contact with another node.

PRoPHET-related research has been mainly concerned with routing and buffer management, which defines the reachability considering buffer, power, bandwidth, popularity, and prediction, In order to prevent unnecessary spreading of the message, when the message is first delivered to the destination, the destination node and the final forwarding node generate an acknowledgment message, and the node having the acknowledge message contacts the node having the message corresponding to the acknowledgment message And the like. The latter technique has been used to prevent the spread of unnecessary messages in a content sharing environment.

In most delay-tolerant network protocols, such as PRoPHET, which determine whether to forward a message to another node based on probability, the proliferation of messages to increase the transmission rate and the traffic load that can be caused thereby are in conflict of interest. Therefore, it is necessary to appropriately adjust the spread of the message so as to reduce the traffic load rate while maintaining the transmission rate appropriately.

KR 1546759 B1 KR 1414973 B1

 A. Lindgren, A. Doria, E. Davies, and S. Grasic, "Probabilistic routing protocol for intermittently connected networks ", IETF RFC 6693, Aug. 2012.  Kwon Hyung Kwon, Kyung Ho Lee, and Jeon Yun Won, "Improved Unnecessary Message Removal Techniques for Content Sharing in Delay Permitted Networks", Journal of KIIT. Vol. 12, No. 3, pp. 69-76, Mar. 31, 2014. pISSN 1598-8619, eISSN 2093-7571 69.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method of providing a PRoPHET routing protocol improved through message copy restriction.

Another object of the present invention is to provide a recording medium on which a computer program for performing a PRoPHET routing protocol providing method enhanced by the message copy restriction is recorded.

It is still another object of the present invention to provide a system for performing an improved PRoPHET routing protocol providing method through the message copy restriction.

It is yet another object of the present invention to provide an apparatus for performing a method of providing an enhanced PRoPHET routing protocol through message copy restriction.

The method for providing a PRoPHET routing protocol using a message copy restriction according to an embodiment for realizing the above-described present invention includes exchanging a summary vector (SV) containing information of a node with a correspondent node ; Confirming whether the message is overlapped with the counterpart node; Comparing the message delivery count (DupC) with the counterpart node and updating the message delivery count with a larger value if the message is duplicated; If the message is not duplicated, comparing the number of times its message is delivered with a threshold (DupC Threshold); Comparing the transmission prediction rate with the counterpart node if the number of times of message delivery is smaller than a threshold value; And delivering a message to the correspondent node when the message transmission prediction rate of the correspondent node is large.

In an embodiment of the present invention, when the message is duplicated, the step of comparing the message delivery count (DupC) with the counterpart node and updating the message delivery count with a larger value may include: After performing the step of checking whether the message is overlapped with the counterpart node for the next message after updating the message delivery count of the counterpart node.

In an exemplary embodiment of the present invention, when the message is not duplicated, comparing the message delivery count with the DupC threshold may further include, when the message delivery count is not less than the threshold, And performing steps subsequent to the step of checking whether the message is overlapped with the correspondent node.

In the embodiment of the present invention, when the number of message delivery times of the own node is smaller than a threshold value, the step of comparing the relative delivery rate with the counterpart node may include: And performing steps subsequent to the step of confirming whether the message is duplicated.

In an exemplary embodiment of the present invention, when the message transmission prediction rate of the counterpart node is large, the step of transmitting a message to the counterpart node may include: increasing the number of message passing times of the counterpart by 1; And transmitting the message transmission count of its own incremented message to the counterpart node together with the message.

In an embodiment of the present invention, the method of providing a PRoPHET routing protocol using the message copy restriction may further include repeating the steps subsequent to the step of checking whether the message is overlapped with the counterpart node .

A computer program for performing a PRoPHET routing protocol providing method using the message copy restriction is recorded in a computer-readable storage medium according to an embodiment of the present invention.

According to another aspect of the present invention, there is provided a destination system for providing a PRoPHET routing protocol using the message copy restriction.

According to another aspect of the present invention, there is provided an apparatus for providing a PRoPHET routing protocol using a message copy restriction, the apparatus comprising: an SV (Summary Vector) A replacement SV exchange part; A message duplication checking unit for checking whether a message is overlapped with the counterpart node; A delivery count updating unit for comparing the number of message deliveries (DupC) with the counterpart node and updating the message delivery count by a larger value when the message is duplicated; A threshold comparison unit for comparing the number of times of message delivery with a threshold value (DupC Threshold) when the message is not duplicated; A transmission prediction rate comparing unit for comparing a transmission prediction rate with the counterpart node when the number of times of message delivery is smaller than a threshold value; And a message delivery unit for delivering a message to the correspondent node when the message delivery prediction rate of the correspondent node is large.

In an exemplary embodiment of the present invention, the PRoPHET routing protocol providing apparatus using the message copy restriction may further include a delivery counting unit for increasing the number of message delivery times by 1 when the message is delivered to the counterpart node.

According to the method of providing the PRoPHET routing protocol using the destination message copy restriction, the message transfer frequency (DupC) is recorded for each message, the message transfer frequency information is updated at the node contact, and only when the pre- Use the predictive rate to deliver the message. In this case, when the PRoPHET protocol, which is a typical routing protocol, is used in a delay tolerant network in which the connectivity between the destination node and the destination node is not guaranteed, duplicate messages that may be generated when the message is copied using only the predicted transmission rate can be reduced.

In this way, unnecessary duplicate messages are prevented from spreading unnecessarily to the destination of the message and the limited buffer capacity of the node can be effectively used by appropriately adjusting the messages necessary for message delivery. Therefore, compared with the existing PRoPHET protocol, Can improve the performance of

1 is a flowchart of a method of providing a PRoPHET routing protocol using a message copy restriction according to an embodiment of the present invention.
2 is an example of a node having a message for explaining the present invention.
FIG. 3 is a diagram illustrating a process of updating the message transfer count DupC when the nodes contact each other in FIG. 2.
FIG. 4 is a diagram illustrating a message transmission restriction in consideration of a threshold value (DupC Threshold) of the number of times of message transfer when nodes are contacted according to the present invention.
5 is a block diagram of a PRoPHET routing protocol providing apparatus using a message copy restriction according to an embodiment of the present invention.

The following detailed description of the invention refers to the accompanying drawings, which illustrate, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different, but need not be mutually exclusive. For example, certain features, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in connection with an embodiment. It is also to be understood that the position or arrangement of the individual components within each disclosed embodiment may be varied without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is to be limited only by the appended claims, along with the full scope of equivalents to which such claims are entitled, if properly explained. In the drawings, like reference numerals refer to the same or similar functions throughout the several views.

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

1 is a flowchart of a method of providing a PRoPHET routing protocol using a message copy restriction according to an embodiment of the present invention.

The present invention records the number of times a message is delivered to another node in a probabilistic routing protocol for intermittently connected networks (PRoPHET), which is one of representative protocols of a delay tolerant network (DTN) This number is updated every time the nodes meet, and is limited to a preset threshold value to prevent duplication of unnecessary duplicate messages.

By limiting the number of transmissions of these messages, we reduce the number of messages that are not valid for the network performance, thereby improving the performance by efficiently utilizing the limited buffer space compared to the existing PRoPHET protocol.

Referring to FIG. 1, a PRoPHET routing protocol providing method using a message copy restriction according to an embodiment of the present invention is a method for providing a PRoPHET routing protocol in which a summary vector (SV) (Step S20).

In the present invention, in order to indirectly estimate how much an arbitrary message is spread to the network, each time the message is copied, the calling node increments the duplication counter (abbreviated as DupC) by one. The SV includes message information stored by each node and each message transmission frequency (DupC).

Also, based on the information of the SV exchanged with the contact node, it is checked whether the message is overlapped with the correspondent node (step S30).

If the message is duplicated, the message transmission frequency DupC is compared with the counterpart node, and the message delivery count is updated with a larger value (steps S31, S33, S35, and S37). That is, when the node and the node have the same message when they contact each other, the DupC value of each node is checked and updated to a larger value.

Specifically, the number of message transmissions (DupC) of the correspondent node (Node B) is compared with the number of message transmissions (DupC) of the correspondent node (Node B) DupC of the node A is greater than the message delivery frequency DupC of the node A itself (node A) (step S31) (Step S33).

In addition, since the message is duplicated, the message delivery count (DupC) is updated without delivering the message, the duplicate message is checked for the next message (for example, the second message) (step S80) S30), and then perform the following steps.

On the other hand, if the number of message deliveries DupC of the correspondent node (node B) to the arbitrary message (e.g., the first message) is larger than the message delivery count DupC of the node A itself (step S35) And updates the message delivery count DupC of itself (node A) to the message delivery count DupC of the partner node (node B) (step S37).

Similarly, since the message is duplicated, the message delivery count (DupC) is updated without delivering the message, and the duplicate message is checked for the next message (e.g., the second message) (step S80) S30), and then perform the following steps. The same holds true even when the message transfer frequency DupC of the node A itself is the same as the message transfer frequency DupC of the correspondent node B (node B).

Referring to FIG. 2 and FIG. 3, a process of updating the message transfer count DupC is shown.

2, the node A has a message a, a message b, a message c, a message d, and a message e, and the number of message deliveries DupC for the messages is 3, 4, 5, 4, and 7, respectively. In addition, the node B has a message a, a message b, a message c, and a message f, and the number of message deliveries DupC for the messages is 5, 4, 1, and 3, respectively.

Referring to FIG. 3, when the node A and the node B in FIG. 2 are in contact with each other, the message transfer count (DupC) of the two nodes is higher than that of the messages a, b, Update.

Specifically, since the number of message deliveries (DupC) of the node A to the message a is 3 and the number of message deliveries (DupC) of the node B is larger when the number of message deliveries (DupC) of the node B is 5, (DupC) of 5 is updated to 5.

On the other hand, when the message delivery frequency (DupC) of the node A is 4 and the message delivery frequency (DupC) of the node B is 4, the message delivery frequency (DupC) The number of message delivery times (DupC) of the node remains unchanged.

In addition, since the number of message deliveries (DupC) of the node A to the message c is 5 and the number of message deliveries (DupC) of the node A is larger when the number of message deliveries DupC of the node B is 1, Update the message delivery count (DupC) to 5.

On the other hand, if the message is not duplicated, it is checked whether the message is overlapped with the correspondent node (step S30). If the message is not duplicated, the number of transmissions of the message is compared with a threshold (DupC Threshold). If it is determined that the message delivery frequency is not less than the predetermined threshold value (DupC Threshold), it is checked whether the message is duplicated (step S30) for the next message (e.g., the second message) Lt; / RTI >

If the number of message delivery times is less than a threshold value, the correspondent node is compared with a delivery prediction rate to check if the message delivery prediction rate of the corresponding node is large (step S50). If the message transmission prediction rate of the counterpart node is not large, it is checked whether the message is duplicated (step S80), and whether the message is duplicated (step S30).

On the other hand, if the message transmission prediction rate of the counterpart node is large, the message is delivered to the counterpart node (step S60). Further, after the message is delivered, the number of transmissions of its own message is increased by 1 and stored, and the number of transmissions of its own message is also transmitted to the correspondent node.

The originating node performs steps subsequent to step S30 for confirming whether the message is duplicated for all messages. To this end, if the last message is confirmed (step S70), the procedure is terminated.

Referring to FIG. 3, the message f is not transmitted to the node A, and the messages d and e not present in the node B are compared with the predicted transmission rates of the respective nodes to the destination nodes of the respective messages, . In this case, the value of the message delivery frequency DupC is incremented by 1 and stored in the source node and the destination node, respectively.

However, in the protocol proposed in the present invention, even if the message transmission probability (DupC) of each node is larger than a preset threshold value, even if the message transmission probability of a new contact node is higher The message is not sent to the new node.

Also, in the protocol proposed in the present invention, it is possible to indirectly deduce how much the corresponding message is spread to the network using the number of message deliveries (DupC), and the diffusion of messages in the network can be controlled by appropriately setting a threshold value (DupC Threshold) And thereby improve performance.

FIG. 4 shows that the message transmission is restricted in consideration of the threshold value (DupC Threshold) of the number of times of message transmission in the inter-node contact according to the present invention.

Referring to FIG. 4, when a node A and a node B are in contact with each other, a message not present to the other node can be transmitted to another node if the message does not exceed a threshold value (DupC Threshold). For example, when the threshold value (DupC Threshold) is 100, the node A determines that the current message delivery count (DupC) value among the messages d, e, and f, which is not a message of the node B, is smaller than the threshold value (DupC Threshold) , I.e., greater than or equal to the threshold, the message is not delivered.

On the other hand, the node A determines the transmission predictive value of the node A and the node B for the message e whose current message delivery count (DupC) is less than the threshold (DupC Threshold) among the messages d, e, Compare. (DupC) value is increased by 1 and the increased message transmission frequency (DupC) value is transmitted to the node B together with the message e when the transmission prediction rate of the node B is larger.

As described above, in the present invention, when two nodes exchanges a summary vector (SV) containing information of a correspondent node at the time of contact, if there is a duplicate message, the node compares the message of the correspondent node with the message delivery frequency (DupC) Update the number of channel message delivery (DupC).

Also, for a message that is not in the correspondent node, only when the message delivery frequency (DupC) of the message is smaller than a predetermined threshold (DupC Threshold), the transmission prediction rate is compared as in PRoPHET, . At the originating node, this procedure is repeated for all messages.

Accordingly, the performance of the PRoPHET protocol can be improved by effectively preventing the spread of unnecessary duplicate messages and appropriately adjusting the messages necessary for message delivery, and efficiently using the limited buffer space of the node.

In the present invention, the message delivery frequency (DupC), which is the number of times a message is transmitted to another node, is measured and the number of times of transmission is limited to a threshold value (DupC Threshold) to appropriately adjust the spread of the message, thereby improving the performance of the PRoPHET protocol We propose an improved PRoPHET routing protocol through message copy restriction.

As such, the PRoPHET routing protocol providing method using the message copy restriction can be implemented in an application or can be implemented in the form of program instructions that can be executed through various computer components and recorded in a computer-readable recording medium. The computer-readable recording medium may include program commands, data files, data structures, and the like, alone or in combination.

The program instructions recorded on the computer-readable recording medium may be ones that are specially designed and configured for the present invention and are known and available to those skilled in the art of computer software.

Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tape, optical recording media such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like.

Examples of program instructions include machine language code such as those generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules for performing the processing according to the present invention, and vice versa.

5 is a block diagram of a PRoPHET routing protocol providing apparatus using a message copy restriction according to an embodiment of the present invention.

The PRoPHET routing protocol providing apparatus 10 (hereinafter, referred to as a device) using the message copy restriction according to the present invention is effective in the network performance by limiting the number of transmissions of messages in a delay tolerant network (DTN) It improves the performance of the PRoPHET protocol by efficiently using the limited buffer space by reducing the number of unacknowledged messages.

5, the apparatus 10 according to the present invention includes an SV exchange unit 100, a message duplication checking unit 300, a transfer count updating unit 400, a threshold value comparing unit 500, 700 and a message transferring unit 900. The apparatus 10 may further include a transfer counting unit 800. The device 10 may be formed in the PRoPHET network to control all the nodes, or may be formed at each node differently.

The apparatus 10 of the present invention can be installed and executed by software (application) for executing a PRoPHET routing protocol using a message copy restriction. The SV exchange 100, the message duplication checking unit 300, The configuration of the transfer count updating unit 400, the threshold value comparing unit 500, the transfer predictive value comparing unit 700, the transfer count counting unit 800 and the message transferring unit 900 is the same as that of the device 10, Lt; RTI ID = 0.0 > PRoPHET < / RTI >

The device 10 may be a separate terminal or some module of the terminal. The SV exchange unit 100, the message duplication checking unit 300, the transfer count updating unit 400, the threshold comparing unit 500, the transfer prediction rate comparing unit 700, (800) and the message transferring unit (900) may be formed of an integrated module or one or more modules. However, conversely, each configuration may be a separate module.

The device 10 may be mobile or stationary. The device 10 may be in the form of a server or an engine and may be a device, an apparatus, a terminal, a user equipment (UE), a mobile station (MS) a wireless device, a handheld device, and the like.

The device 10 may execute or produce various software based on an operating system (OS), i.e., a system. The operating system is a system program for allowing software to use the hardware of a device. The operating system includes a mobile computer operating system such as Android OS, iOS, Windows Mobile OS, Sea OS, Symbian OS, Blackberry OS, MAC, AIX, and HP-UX.

The SV exchange unit 100 exchanges an SV (Summary Vector) containing information of a node with a correspondent node at the time of inter-node contact. The SV includes message information stored by each node and each message transmission frequency (DupC).

In the present invention, the delivery counting unit 800 indirectly deduces how much a certain message is diffused to the network, and each time the message is copied, the sending node increments the duplication counter (abbreviated as DupC) .

The message duplication checking unit 300 checks whether the message is overlapped with the counterpart node. If the message is duplicated, the message duplication checking unit 300 notifies the delivery count updating unit 400, and the delivery count updating unit 400 compares the message delivery count DupC with the counterpart, ≪ / RTI > updates the number of message delivery times for this larger number. That is, when the node and the node have the same message when they contact each other, the DupC value of each node is checked and updated to a larger value.

On the other hand, if the message does not overlap with the counterpart node, the message duplication checking unit 300 notifies the threshold comparison unit 500 of the message, and the threshold comparison unit 500 determines Compare with the threshold (DupC Threshold). If the number of message delivery times is not less than the threshold value (DupC Threshold), the message duplication checking unit 300 checks whether the next message is duplicated.

The threshold comparison unit 500 notifies the transmission prediction ratio comparison unit 700 of the transmission rate of the own node and the transmission prediction rate comparison unit 700 compares the transmission prediction rate with the corresponding node , It is confirmed whether the message transmission prediction rate of the counterpart node is large. If the message transmission prediction rate of the counterpart node is not large, the message duplication checking unit 300 checks whether the next message is duplicated.

On the other hand, when the message transmission prediction rate of the counterpart node is large, the transmission prediction ratio comparison unit 700 notifies the message transmission unit 900 of the result, and the message transmission unit 900 transmits a message to the counterpart node .

Also, the transfer count counting unit 800 increases the number of message delivery times by one after the message is delivered, and transmits the increased message delivery count to the counterpart node. In the present invention, the number of times a message is delivered to another node is recorded, and this number is updated every time the nodes meet to limit the threshold to a preset threshold value.

At the originating node, this procedure is repeated for all messages.

As a result, messages can be delivered more carefully than existing PRoPHETs, and the limited buffer capacity can be effectively used, which improves the transmission rate, load rate, and propagation delay compared to the existing PRoPHET protocol.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims. You will understand.

The present invention proposes an enhanced PRoPHET protocol by reducing unnecessary duplicate message copy that occurs while transmitting a message by comparing only the calculated predicted rate based on the past contact information of the PRoPHET protocol in the inter-node message delivery, and is usefully applied to a delay tolerant network .

10: PRoPHET routing protocol provided device
100: SV exchange section
300: message duplication confirmation unit
400: transfer count update unit
500: Threshold comparison unit
700: transmission prediction ratio comparison unit
800: Number of transfer counts
900:

Claims (10)

Exchanging a summary vector (SV) containing information of a node with a correspondent node when the nodes are in contact with each other;
Confirming whether the message is overlapped with the counterpart node;
Comparing the message delivery count (DupC) with the counterpart node and updating the message delivery count with a larger value if the message is duplicated;
If the message is not duplicated, comparing the number of times its message is delivered with a threshold (DupC Threshold);
Comparing the transmission prediction rate with the counterpart node if the number of message delivery times is less than a threshold value; And
And transmitting a message to the counterpart node if the message transmission prediction rate of the counterpart node is large,
Comparing the message delivery count (DupC) with the counterpart node and updating the message delivery count with a larger value, when the message is duplicated,
The method of claim 1, further comprising, after updating the number of message delivery times or the number of message delivery times of the counterpart node, checking whether the message is overlapped with the counterpart node for the next message A method for providing a PRoPHET routing protocol.


delete 2. The method of claim 1, wherein if the message is not duplicated, comparing the number of times the message is delivered with a threshold value (DupC Threshold)
The method of claim 1, further comprising the steps of: if the number of message delivery times is not less than a threshold value, performing a subsequent step of checking whether the message is overlapped with the counterpart node for a next message .
2. The method of claim 1, wherein if the number of message delivery times is less than a threshold value,
The method of claim 1, further comprising the step of determining whether the message is overlapped with the counterpart node for the next message when the message transmission predictive rate of the counterpart node is not large.
2. The method of claim 1, wherein, when the message delivery prediction rate of the correspondent node is large,
Increasing the number of message delivery times by 1; And
And forwarding the number of message transmissions of its own to the counterpart node together with the message incremented by 1, using the message copy restriction.
The method according to claim 1,
Further comprising the step of repeatedly performing steps subsequent to the step of checking whether the message is overlapped with the counterpart node for all the messages having the same message repetition.
A computer-readable recording medium having recorded thereon a computer program for performing a method of providing a PRoPHET routing protocol using a message copy restriction according to any one of claims 1, 6,
A PRoPHET protocol provision system for performing a PRoPHET routing protocol provision method using a message copy restriction according to any one of claims 1 to 6.
An SV exchange unit for exchanging an SV (Summary Vector) containing information of a node with a correspondent node when the nodes are in contact with each other;
A message duplication checking unit for checking whether a message is overlapped with the counterpart node;
A delivery count updating unit for comparing the number of message deliveries (DupC) with the counterpart node and updating the message delivery count by a larger value when the message is duplicated;
A threshold comparison unit for comparing the number of times of message delivery with a threshold value (DupC Threshold) when the message is not duplicated;
A transmission prediction rate comparing unit for comparing a transmission prediction rate with the counterpart node when the number of times of message delivery is smaller than a threshold value; And
And a message delivery unit for delivering a message to the correspondent node when the message delivery prediction rate of the correspondent node is large,
Wherein the message duplication checking unit uses a message copy restriction to check whether a message is overlapped with a partner node for a next message when the message delivery count of the self is not smaller than a threshold value.
10. The method of claim 9,
Further comprising a delivery counting unit for incrementing the number of delivering a message by 1 when the message is delivered to the counterpart node.

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