JP5022091B2 - Communication device - Google Patents

Description

  The present invention relates to a communication apparatus that performs multi-hop communication using, for example, a wireless ad hoc network.

  A wireless ad hoc network is a network that is autonomously formed by a plurality of wireless terminal devices, and can flexibly change the transmission path according to the situation of movement, new participation, departure, etc. of the wireless terminal device. Network. In a wireless ad hoc network, packet loss is likely to occur due to external noise, multipath, fading, shielding, terminal movement, and the like, and the communication quality of the route is likely to change.

  Therefore, in a wireless ad hoc network, in order to transmit a video or audio stream (hereinafter referred to as “video stream”) without interruption, the link state on the route is always grasped, and an optimum route according to the link state is obtained. Route control is required to quickly select and switch between.

  As conventional route control, route control led by a node that transmits packets (for example, refer to Non-Patent Document 1) or route control that is led by a node that receives packets. Receiving-side route control (for example, see Non-Patent Document 2) is known. Hereinafter, this will be specifically described with reference to FIG. FIG. 7 shows a wireless ad hoc network composed of a transmission source node S, an intermediate node I, and a destination node D. FIGS. 7A to 7G show transmission-side route control, and FIGS. 7H to 7K show reception-side route control.

  First, in transmission-led route control, when a packet is transmitted from the source node S to the destination node D (FIG. 7A), the destination node D transmits a packet indicating that the packet has been received every time a packet is received. It returns to the node S (FIG. 7B). When communication between the transmission source node S and the destination node D becomes impossible (FIG. 7C), the destination node D cannot receive the packet and does not return it to the transmission source node S. As a result, the transmission source node S detects communication disconnection (FIG. 7 (d)), starts route search (FIG. 7 (e)), confirms route establishment (FIG. 7 (f)), and then transmits. It can be resumed (FIG. 7 (g)).

  On the other hand, when the packet is transmitted from the transmission source node S to the destination node D in the routing control led by the reception side (FIG. 7 (h)), the communication between the transmission source node S and the destination node D becomes impossible. D detects the disconnection of communication (FIG. 7 (i)). As a result, the destination node D starts route search (FIG. 7 (j)), and the transmission source node S resumes transmission on the route where the packet from the destination node D arrives (FIG. 7 (k)). Will be able to.

As described above, the reception-side route control can be quickly switched from the route in which the communication failure has occurred to a new route, compared to the transmission-side route control. Therefore, in order to transmit a stream of video and the like without interruption, it is preferable to employ a path control led by the reception side.
C. E. Perkins, E .; M.M. Royer, and S.R. R. Das, “Ad Hoc On-Demand Distance Vector (AODV) Routing”, IETF Mobile Ad Hoc Networks Working Group, IETF RFC 3561 H. Fujisawa et al. , "Route Selection using Retransmission Packets for Video Streaming on AdHoc Networks", IEEE Radio & Wireless Symposium 2006

  However, in the route control led by the reception side, the route may be divided during transmission of a stream such as a video.

For example, as shown in FIG. 8A, it is assumed that a stream such as a video is transmitted from the transmission source node S to the destination node D via the relay nodes I ₁ and I ₂ . It is assumed that the link between the intermediate nodes I ₁ and I ₂ and the link between the intermediate node I ₂ and the destination node D are interrupted at a certain moment (FIG. 8B). The destination node D requests the intermediate node I ₁ to change the route (FIG. 8C), and the intermediate node I ₂ requests the source node S to change the route (FIG. 8D). As a result, the source node S would then initiate a transfer such as video streams to the intermediate node I _2, does not reach the video such stream to the destination node D (FIG. 8 (e)). Furthermore, the source node S, because you do not know that it is now no longer receive video such stream to the destination node D, will continue to transfer the video or the like stream as it continues to the intermediate node I _2.

  As described above, the reception-side route control has a problem that the route is divided when a plurality of nodes simultaneously switch the route.

  SUMMARY An advantage of some aspects of the invention is that it provides a communication device that can transmit a stream of video and the like without interruption.

  The communication apparatus according to the present invention is a maintenance packet transmitting / receiving unit for transmitting / receiving a maintenance packet for maintaining a route for transferring the data packet between a transmission source node that transmits the data packet and a destination node that is a destination of the data packet. And a route control means for performing route control based on information included in the maintenance packet. The maintenance packet is issued periodically by the destination node, and is issued by the destination node for each issue. It has a configuration having issuance order information indicating the order and transmission node information indicating the transmission node that has transmitted the maintenance packet.

  With this configuration, the communication device of the present invention can control the route based on the issue order information of the maintenance packet and the transmission node information, thereby selecting the optimum route and transmitting the data packet. Streams can be transmitted without interruption.

  The communication apparatus of the present invention further includes route table storage means for storing data of a route table indicating a transfer route of the data packet, and the maintenance packet transmitting / receiving means transmits the maintenance packet based on the route table. It has a configuration.

  With this configuration, the communication device of the present invention can transmit a maintenance packet to a data packet transmission source node or a node that can establish a link with high communication quality determined by route search, so an optimal route is selected. Thus, a data packet can be transmitted, and a stream such as a video can be transmitted without interruption.

  Furthermore, the communication apparatus of the present invention has a configuration provided with a route disconnection information acquisition unit that acquires information on a disconnection of a route for transferring the data packet based on the issue order information.

  With this configuration, the communication device of the present invention can determine that one of the routes has been disconnected when the issue order information of the received maintenance packet is not updated even after a predetermined time has elapsed. By selecting an optimum route, a video stream can be transmitted without interruption.

  Further, the communication device of the present invention includes a maintenance packet generation unit that periodically generates the maintenance packet, and an issue order information grant that updates and issues the issue order information to the maintenance packet generated by the maintenance packet generation unit And means.

  With this configuration, when the communication apparatus of the present invention is a destination node of a data packet, it can periodically generate a maintenance packet, update and issue issue order information, and transmit it to a predetermined node.

  Furthermore, in the communication apparatus of the present invention, the maintenance packet generating unit generates the maintenance packet periodically, and the maintenance packet generating unit generates the issue order information included in the maintenance packet received by the maintenance packet transmitting / receiving unit. And an issue order information adding means for adding to the maintenance packet.

  With this configuration, when relaying a data packet, the communication device of the present invention can add the issued maintenance packet issue order information to the generated maintenance packet and transmit it to a predetermined node.

  Furthermore, the communication device of the present invention has a configuration in which, when the maintenance packet transmitting / receiving unit receives a plurality of maintenance packets, the route control unit performs route control based on a maintenance packet having the latest issue order information. ing.

  With this configuration, the communication apparatus of the present invention can transmit a stream of video and the like without interruption by transmitting a data packet using a route through which the latest maintenance packet is transferred.

  Furthermore, the communication apparatus of the present invention has a configuration in which the maintenance packet includes communication quality information between predetermined links.

  With this configuration, the communication apparatus according to the present invention can acquire communication quality information between predetermined links, so that an optimal path can be selected and a video stream can be transmitted without interruption.

  Further, the communication device according to the present invention, the data packet has issue order information given by the transmission source node, based on the issue order information of the maintenance packet and the issue order information of the data packet Transmission time information acquisition means for acquiring information on transmission time between the data packets, and when the intermediate node that relays the data packet is between the predetermined nodes, the transmission time is determined by the data packet passing through the intermediate node. It has a configuration including the time to be transmitted.

  With this configuration, the communication device of the present invention can acquire information on transmission time between predetermined nodes regardless of the presence or absence of an intermediate node that relays a data packet. It can be used for reduction processing, route control for searching for a new route, and the like. As a result, the communication apparatus of the present invention can select an optimum route with a shorter transmission time and transmit a video stream without interruption.

  The present invention can provide a communication apparatus having an effect of being able to transmit a stream such as a video without interruption.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. An example in which the communication device of the present invention is applied to a device that transmits a data packet of a video stream etc. via a wireless ad hoc network will be described.

  First, the configuration of the communication device in the present embodiment will be described.

  As shown in FIG. 1, the communication device 10 according to the present embodiment includes a packet receiver 11 that receives a packet, a packet transmitter 12 that transmits a packet, a packet distributor 13 that distributes the received packet, and data A data packet transfer processing unit 14 for transferring packets, a maintenance packet processing unit 15 for processing maintenance packets, a route quality monitoring unit 16 for monitoring route quality, and a route table storage unit 17 for storing route table data A maintenance packet generating unit 18 that generates a maintenance packet, a sequence number adding unit 19 that assigns a sequence number, and an application unit 20 that processes the data packet. Note that the communication device 10 according to the present embodiment operates by including hardware such as a CPU and a memory, and a program executed on the hardware.

  The packet receiving unit 11 and the packet transmitting unit 12 are configured by wireless modules that perform ad-hoc wireless communication. Packets processed by the packet receiving unit 11 and the packet transmitting unit 12 include a data packet of a video stream and the like, and a maintenance packet for maintaining the wireless ad hoc network.

  For example, as shown in FIG. 2, the maintenance packet includes packet type information indicating the packet type, transmission address information indicating the transmission source of the maintenance packet, sequence number information indicating the order in which the maintenance packets are issued, such as received electric field strength. It has link quality information indicating communication quality between links.

  The link quality information is not essential and can be omitted depending on the situation. As will be described later, the sequence number is updated by a destination node that is a destination of a stream such as a video. This sequence number corresponds to the issue order information described in the claims. The issue order information is not limited to the sequence number, and may be any information that can specify the issue order of the maintenance packets. The transmission address information corresponds to the transmission node information described in the claims. The transmission node information is not limited to the transmission address information, and may be any information that can identify the node that transmitted the maintenance packet.

  The packet receiving unit 11 receives data packets and maintenance packets of video streams and outputs them to the packet sorting unit 13. The packet receiver 11 corresponds to the maintenance packet transmitting / receiving means of the present invention.

  The packet transmission unit 12 is configured to transmit a video data stream data packet from the data packet transfer processing unit 14 and a maintenance packet from the sequence number assigning unit 19. The packet transmitter 12 corresponds to the maintenance packet transmission / reception means of the present invention.

  The packet distribution unit 13 distributes the packets received by the packet reception unit 11, and distributes the data packets of the video stream etc. to the data packet transfer processing unit 14 and the maintenance packets to the maintenance packet processing unit 15, respectively. Is.

  The data packet transfer processing unit 14 performs data-directed path control and transfers data packets. At that time, the data packet transfer processing unit 14 refers to the routing table stored in the routing table storage unit 17. The data packet transfer processing unit 14 corresponds to the route control means of the present invention.

  The maintenance packet processing unit 15 registers the source address of the maintenance packet acquired from the transmission address information of the maintenance packet in the route table of the route table storage unit 17 as the transmission destination address of the video stream. The maintenance packet processing unit 15 outputs the maintenance packet sequence number information and link quality information to the path quality monitoring unit 16.

  Further, the maintenance packet processing unit 15 has a memory (not shown) for storing sequence number information. The maintenance packet processing unit 15 stores the sequence number information of the maintenance packet in this memory and also outputs it to the sequence number giving unit 19. ing. In addition, when the maintenance packet processing unit 15 receives a maintenance packet having a sequence number smaller than the sequence number stored in the memory, that is, an old sequence number, the maintenance packet is ignored.

  Further, the maintenance packet processing unit 15 determines that one of the routes for transferring the data packet is disconnected when the sequence number of the received maintenance packet is not updated even after a predetermined time has elapsed. The maintenance packet processing unit 15 corresponds to the route cut information acquisition unit of the present invention.

  The route quality monitoring unit 16 monitors the link state between nodes in the wireless ad hoc network based on the sequence number information and link quality information of the maintenance packet.

  The routing table storage unit 17 is configured to store routing table data in which transmission source and transmission destination node information related to video data stream data packets is described. The route table storage unit 17 corresponds to the route table storage means of the present invention.

  The maintenance packet generator 18 refers to the routing table in the routing table storage unit 17 and periodically generates a maintenance packet, and corresponds to the maintenance packet generator of the present invention. Here, “periodic” means to be performed every number of received packets of a stream such as a video or every predetermined time. In the present embodiment, it is assumed that the maintenance packet generator 18 generates a maintenance packet every predetermined time. The maintenance packet generated by the maintenance packet generator 18 is transmitted to a predetermined node based on the route table. This means that a maintenance packet is transmitted to a transmission source node of a stream such as a video or a node that can establish a high-quality link determined by route search or the like.

  When the own node is a destination node of a video or the like stream, the sequence number assigning unit 19 updates the sequence number every time the maintenance packet generating unit 18 generates a maintenance packet and assigns the sequence number to the maintenance packet. On the other hand, when the own node is other than the destination node of the video stream, the sequence number assigning unit 19 uses the maintenance packet generated by the maintenance packet generating unit 18 to generate the sequence number information acquired by the maintenance packet processing unit 15 from the received maintenance packet. It is supposed to be granted to. The sequence number assigning unit 19 corresponds to the issue order information assigning means of the present invention.

  The application unit 20 is capable of outputting a video stream to another node when the node is the transmission source node of the video stream. The application unit 20 can store and execute a video stream addressed to the own node when the node is a destination node of the video stream.

Next, the operation of communication apparatus 10 in the present embodiment will be described using FIG. FIG. 3 shows a transmission source node S that transmits a video stream, a destination node D that is a destination of the video stream, and an intermediate node I ₁ that relays the video stream between the transmission source node S and the destination node D. , I ₂ and I ₃ . Each node includes the communication device 10 according to the present embodiment.

As shown in FIG. 3 (a), it is assumed that a video stream is transmitted in the order of transmission source node S → intermediate node I ₁ → intermediate node I ₂ → destination node D.

In the destination node D, the maintenance packet generator 18 generates a maintenance packet every predetermined time. Next, the sequence number assigning unit 19 assigns, for example, information of sequence number (seq) = 1 to the maintenance packet. Subsequently, the packet transmission unit 12 transmits a maintenance packet (seq = 1) to the intermediate node I ₂ (FIG. 3B).

Then, the intermediate node _{I 2,} the packet receiver 11 receives the maintenance packet (seq = 1). Next, the packet sorting unit 13 outputs the received maintenance packet to the maintenance packet processing unit 15.

  Subsequently, the maintenance packet processing unit 15 acquires the sequence number information of the received maintenance packet and stores it in the memory. Further, the maintenance packet processing unit 15 registers the transmission source address of the maintenance packet acquired from the transmission address information of the maintenance packet in the route table of the route table storage unit 17 as the transmission destination address of the video stream. Further, the maintenance packet processing unit 15 outputs the sequence number information of the maintenance packet to the sequence number giving unit 19. Further, the maintenance packet processing unit 15 outputs the sequence number information and link quality information of the maintenance packet to the path quality monitoring unit 16. The route quality monitoring unit 16 monitors the link state between nodes by acquiring sequence number information and link quality information.

  The maintenance packet generator 18 generates a maintenance packet and outputs it to the sequence number assigning unit 19. Note that the maintenance packet generation unit 18 refers to the routing table to determine that the own node is not a maintenance packet destination node that is a data packet transmission source node.

  Since the own node is not the destination node, the sequence number assigning unit 19 assigns the sequence number information acquired from the maintenance packet processing unit 15 to the maintenance packet and outputs the maintenance packet to the packet transmitting unit 12.

The packet transmitter 12 transmits the maintenance packet (seq = 1) to the intermediate node I ₁ (FIG. 3 (c)).

The intermediate node I ₁ performs the same processing as the intermediate node I ₂ and transmits a maintenance packet (seq = 1) to the transmission source node S (FIG. 3C).

Similarly thereafter, the maintenance packet generator 18 of the destination node D generates a maintenance packet every predetermined time, the destination node D sequentially outputs maintenance packets seq = 2,3 · · · to the intermediate node I ₂ .

As described above, in a state in which the video stream is transmitted in the order of the transmission source node S → the intermediate node I ₁ → the intermediate node I ₂ → the destination node D, each node on the path has the maintenance packet generator 18. Periodically generate and output maintenance packets.

Next, a case where a plurality of links are disconnected at a certain moment due to movement of a person or an object in a wireless ad hoc network will be described with reference to FIG. FIG. 4 shows a transmission source node S that transmits a video stream, a destination node D that is a destination of the video stream, and an intermediate node I ₁ that relays the video stream between the transmission source node S and the destination node D. And a wireless ad hoc network configured with I ₂ . Each node includes the communication device 10 according to the present embodiment.

FIG. 4A shows a state in which the maintenance packet (seq = 1) output from the destination node D is transmitted to the transmission source node S via the intermediate nodes I ₂ and I ₁ .

After the source node S receives the maintenance packet (seq = 1), the links between the intermediate nodes I ₁ and I ₂ and the intermediate node I ₂ and the destination node D are disconnected almost at the same moment. (FIG. 4B).

In this case, the destination node D requests the intermediate node I ₁ to change the route by using the newly generated maintenance packet (seq = 2) (FIG. 4C). The intermediate node I ₁ transmits a maintenance packet (seq = 2) to the transmission source node S. The intermediate node I ₂ transmits a maintenance packet (seq = 1) to the transmission source node S with a delay (FIG. 4 (d)).

Here, the transmission source node S compares the sequence numbers of the two maintenance packets received from the intermediate nodes I ₁ and I ₂ . Maintenance packet from the intermediate node _{I 2} (seq = 1), since older than the maintenance packet from the intermediate node _{I 1} (seq = 2), the maintenance packet processing unit 15 of the source node S, the intermediate node _{I 2} The maintenance packet (seq = 1) is ignored.

As a result, the data packet transfer processing unit 14 of the transmission source node S selects a route that reaches the destination node D via the intermediate node I ₁ , and the packet transmission unit 12 directs the video stream to the intermediate node I ₁ . (FIG. 4E).

  As described above, all the nodes including the communication device 10 according to the present embodiment are managed based on the sequence number information generated by the destination node D, and a plurality of links are disconnected almost simultaneously at a certain moment. Even if it is done, a new route can be selected and a video stream can be transmitted without interruption.

Next, a new route setting when a link is disconnected in a wireless ad hoc network will be described with reference to FIG. FIG. 5 shows a source node S that transmits a video stream, a destination node D that is a destination of the video stream, and an intermediate node I ₁ that relays the video stream between the source node S and the destination node D. , I ₂ and I ₃ . Each node includes the communication device 10 according to the present embodiment.

As shown in FIG. 5 (a), the link between the intermediate node I ₂ and the destination node D is disconnected. When any link between the source node S and the destination node D is disconnected, the maintenance packet from the destination node D does not arrive, so the sequence number of the maintenance packet that reaches the source node S has passed a predetermined time. However, it is not updated (FIGS. 5B and 5C).

As a result, the transmission source node S determines that one of the links between the transmission source node S and the destination node D is disconnected, and the video stream does not reach the destination node D. Therefore, the source node S, by initiating a route search to the destination node D (FIG. 5 (d)), to select a new route via an intermediate node I _3, the destination node such as video streams D (FIG. 5E). A new route search can be performed by, for example, an AODV route request, a route reply, or the like.

Next, the use of sequence number information for route quality control will be described with reference to FIG. FIG. 6 shows a source node S that transmits a video stream, a destination node D that is a destination of the video stream, and an intermediate node I ₁ that relays the video stream between the source node S and the destination node D. And a wireless ad hoc network configured with I ₂ . Each node includes the communication device 10 according to the present embodiment.

FIG. 6A shows the transmission state of the maintenance packet at a certain moment, and “Mseq” indicates the sequence number of the maintenance packet. That is, the destination node D maintenance packet (Mseq = 8) to the intermediate node _{I 2,} the intermediate node _{I 2} is a maintenance packet (Mseq = 7) to the intermediate node _{I 1,} the intermediate node _{I 1} maintenance packet (MSEQ = 6 ) To the transmission source node S, respectively.

  As shown in FIG. 6A, the sequence number of the maintenance packet transmitted from each node at a certain moment is different one by one.

Therefore, every time the transmission source node S receives the maintenance packet, the sequence number of the received maintenance packet is added to the data packet of the stream such as a video and transmitted at a certain moment as shown in FIG. It becomes a state. In FIG. 6B, “Mseq” indicates a maintenance packet sequence number, and “Dseq” indicates a data packet sequence number. That is, the source node S sends the data packet (Dseq = 6) to the intermediate node I ₁ , the intermediate node I ₁ sends the data packet (Dseq = 5) to the intermediate node I ₂ , and the intermediate node I ₂ sends the data packet (Dseq = 4) is being transmitted to the destination node D.

  Therefore, the packet distribution unit 13 included in each node compares the sequence number (Mseq) of the maintenance packet with the sequence number (Dseq) of the data packet, and thereby reaches the node from the transmission source node S. Delay information can be acquired. The delay time information corresponds to transmission time information described in the claims. The packet distribution unit 13 included in each node corresponds to the transmission time information acquisition unit of the present invention.

For example, the intermediate node _{I 1,} if the data packet (Dseq = 6) arrives when sending maintenance packets (Mseq = 8), the packet sorting unit 13 of the intermediate node _{I 1} is the source node S and the intermediate It is possible to obtain information that a delay time corresponding to (8-6) = 2 sequence number occurs when a packet makes a round trip with the node I ₁ .

Further, for example, when the data packet (Dseq = 4) arrives at the destination node D when transmitting the maintenance packet (Mseq = 10), the packet sorting unit 13 of the destination node D uses the intermediate nodes I ₁ and I Information that a delay time of (10−4) = 6 sequence numbers occurs when a packet makes one round trip between the transmission source node S and the destination node D via ₂ can be acquired.

  The delay time information acquired as described above can be used for delay time reduction processing in a wireless ad hoc network, for example, hop count reduction processing, route control for searching for a new route, and the like.

  As described above, according to the communication device 10 in the present embodiment, since the route control is performed based on the sequence number information and the transmission node information of the maintenance packet, the optimum route is selected and the data packet is transmitted. can do. Therefore, the communication device 10 according to the present embodiment can transmit a stream such as a video without interruption.

  Further, according to the communication device 10 in the present embodiment, the routing table storage unit 17 stores routing table data indicating the transfer route of the data packet, and the packet transmission unit 12 receives the maintenance packet based on the routing table. Since the transmission configuration is adopted, the maintenance packet can be transmitted to the transmission source of the data packet or a node capable of establishing a link with high communication quality determined by route search. As a result, the communication apparatus 10 according to the present embodiment can select an optimum route and transmit a data packet, and can transmit a stream of video and the like without interruption.

  Moreover, according to the communication apparatus 10 in the present embodiment, since the configuration is such that the information that the route for transferring the data packet is cut is acquired based on the sequence number information, the issue order information of the received maintenance packet is the predetermined time. If it is not updated even after the elapse of time, it can be determined that one of the routes has been disconnected, and by searching for the route and selecting the optimum route, a stream such as a video can be transmitted without interruption.

  Further, according to the communication device 10 in the present embodiment, when a plurality of maintenance packets are received, the route control is performed based on the maintenance packet having the latest sequence number information, so that the latest maintenance packet is transferred. By transmitting the data packet using the route, the video stream can be transmitted without interruption.

  Also, according to the communication device 10 in the present embodiment, since the maintenance packet has the communication quality information between the links, the optimal route is selected by acquiring the communication quality information between the links, and the video Equal streams can be transmitted without interruption.

  Further, according to communication apparatus 10 in the present embodiment, transmission between predetermined nodes is performed based on the sequence number information of the maintenance packet and the sequence number information of the data packet, regardless of whether or not there is an intermediate node that relays the data packet. Since it is configured to acquire time information, transmission time information can be acquired regardless of whether or not there is an intermediate node between predetermined nodes, and an optimal route based on the acquired transmission time information. The video stream can be transmitted without interruption.

  Note that a data packet transmission program for seamlessly transmitting a video stream can be produced by realizing the communication device 10 in the present embodiment by a computer and programming the operation of the communication device 10 described above.

  As described above, the communication device according to the present invention has an effect that a stream such as a video can be transmitted without interruption, and is useful as a communication device that performs multi-hop communication using a wireless ad hoc network.

The block diagram which shows the structure in one Embodiment of the communication apparatus which concerns on this invention. The figure which shows the structure of the maintenance packet in one Embodiment of the communication apparatus which concerns on this invention. Explanatory drawing of operation in a wireless ad hoc network in an embodiment of a communication apparatus according to the present invention Explanatory drawing of operation | movement when the some link of a radio | wireless ad hoc network is cut | disconnected at a certain moment in one Embodiment of the communication apparatus which concerns on this invention. Explanatory drawing about the new path | route setting when the link of a wireless ad hoc network is cut | disconnected in one Embodiment of the communication apparatus which concerns on this invention Explanatory drawing when sequence number information is used for quality control of a route in an embodiment of a communication apparatus according to the present invention Explanatory drawing of conventional route control (a) Explanatory diagram of route control led by transmission side (b) Explanatory drawing of route control led by reception side Explanatory diagram of problems in conventional receiver-side route control

Explanation of symbols

10 Communication device 11 Packet receiver (maintenance packet transmission / reception means)
12 Packet transmitter (maintenance packet transmission / reception means)
13 Packet distribution part (transmission time information acquisition means)
14 Data packet transfer processing unit (route control means)
15 Maintenance packet processing unit (route disconnection information acquisition means)
16 route quality monitoring unit 17 route table storage unit (route table storage means)
18 Maintenance packet generator (maintenance packet generator)
19 Sequence number giving section (issue order information giving means)
20 Application Department

Claims (8)

A maintenance packet transmitting / receiving unit configured to transmit and receive a maintenance packet for maintaining a route for transferring the data packet between a transmission source node that transmits the data packet and a destination node that is a destination of the data packet; and the maintenance packet includes Route control means for performing route control based on information,
The maintenance packet is periodically issued by the destination node, issuance order information indicating the order of issue given by the destination node for each issuance, and transmission node information indicating a transmission node that has transmitted the maintenance packet; A communication apparatus comprising: Route table storage means for storing data of a route table indicating a transfer route of the data packet;
The communication apparatus according to claim 1, wherein the maintenance packet transmitting / receiving unit transmits the maintenance packet based on the route table. The communication apparatus according to claim 1, further comprising: a path disconnection information acquisition unit configured to acquire information on a disconnection of a path for transferring the data packet based on the issue order information. A maintenance packet generation unit that periodically generates the maintenance packet, and an issue order information adding unit that updates and issues the issue order information to the maintenance packet generated by the maintenance packet generation unit. The communication device according to any one of claims 1 to 3. Maintenance packet generating means for periodically generating the maintenance packet, and an issue order for giving the issue order information included in the maintenance packet received by the maintenance packet transmitting / receiving means to the maintenance packet generated by the maintenance packet generating means The communication apparatus according to claim 1, further comprising an information adding unit. 6. When the maintenance packet transmitting / receiving unit receives a plurality of maintenance packets, the route control unit performs route control based on a maintenance packet having the latest issue order information. The communication device according to any one of the above. The communication apparatus according to any one of claims 1 to 6, wherein the maintenance packet includes communication quality information between predetermined links. The data packet has issue order information given by the transmission source node, and acquires information on a transmission time between predetermined nodes based on the issue order information of the maintenance packet and the issue order information of the data packet. Transmission time information acquisition means is provided, and when the intermediate node that relays the data packet is between the predetermined nodes, the transmission time includes a time during which the data packet is transmitted via the intermediate node. The communication device according to any one of claims 1 to 7.

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