JP2016152592A - Route information collection program, route information collection method, and node device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for supporting tracking survey about a route when a communication failure occurs.SOLUTION: A node device included in a plurality of node devices constructing a communication network from a data transmission source to a data transmission destination receives communication information transmitted from other node device. Communication information added with identification information of a node device in a subsequent stage in a communication route of communication to the received communication information is transmitted to a node device in a preceding stage and the node device in the subsequent stage in the communication route.SELECTED DRAWING: Figure 1

Description

  The present specification relates to a route information collection program, a route information collection method, and a node device.

  Ad hoc communication technology refers to communication technology in which devices directly communicate with each other without using an access point. In recent years, each communication device to which the ad hoc communication technology is applied recognizes a surrounding communication device, and wireless ad hoc network technology has attracted attention.

  As an example of an ad hoc network routing protocol (ad hoc protocol), there are a reactive type AODV (Adhoc On Demand Distance Vector Algorithm) and a proactive type OLSR (Optimized Link State Routing). Furthermore, as an example of an ad hoc protocol, prior to a communication request, a path (route) for each node to autonomously perform data communication is built in advance, and an optimal route is learned as needed, and the route is changed proactively. There is a type routing protocol.

The following technologies are examples of technologies related to ad hoc networks.
As a first technique, there is a packet routing method in a system that transmits a packet to a destination wireless terminal device via a plurality of wireless terminal devices (for example, Patent Document 1). In the first technique, a wireless terminal device that relays a packet monitors path disconnection. The wireless terminal device that has detected the route disconnection transmits a route search packet to the destination wireless terminal device of the packet, and notifies the source wireless terminal device of the route disconnection. The relaying wireless terminal device reconstructs the packet transfer route according to the route search packet. The transmission source wireless terminal device performs route reconstruction when it receives information on route breakage.

  As a second technique, there is a packet routing method in a system that transmits a packet to a destination wireless terminal via a plurality of wireless terminal devices (for example, Patent Document 2). In the second technique, it is detected that communication with a wireless terminal device that directly transmits a packet using a wireless signal is disconnected by a relaying wireless terminal device. The wireless terminal device that has detected that the communication has been disconnected determines whether the device is located on the side of the packet destination wireless terminal device or the transmission source wireless terminal device. The wireless terminal device that has been determined to be on the transmitting wireless terminal device side transmits a request signal for route repair to the wireless terminal device that is the destination of the packet by broadcast. When the wireless terminal device that is the destination of the packet makes a route repair request signal, the wireless terminal device broadcasts a route reconstruction request addressed to the wireless terminal device that is the source of the packet.

  As a third technique, there is a technique in which an appropriate route is selected and data is transmitted as a result of autonomous distributed processing by each node device as the entire network (for example, Patent Document 3). In the third technique, when a frame that has been transmitted by a node device is received by the node device itself via the network, an adjacent node device different from the previously selected adjacent node device is tried as a transmission destination. If there is no adjacent node device that can transmit, the received frame is transmitted to the third adjacent node device by the backtracking means, so that the third adjacent node device can try another new route. it can.

  As a fourth technique, there is a technique for monitoring the state of a communication path in a network (for example, Patent Document 4). In the fourth technique, a first node device in a network including a plurality of node devices is configured to transfer a frame addressed to an end node, which is a node device at the end of a route whose communication quality is to be investigated, The transmission destination of the first survey frame used for the route survey is selected. If the first node device fails to transmit the first survey frame to the second node device selected as the transmission destination of the first survey frame, the first node device and the second node device A second survey frame recording that the communication between the two has failed is generated. The first node device selects the third node device that is the transmission destination of the second survey frame from the node devices that are the transfer destination of the frame addressed to the end node. The first node device transmits the second investigation frame to the third node device, so that the communication between the first node device and the second node device is performed via the third node device. Notify the end node of the failure.

JP 2005-269623 A JP 2005-236687 A International Publication No. 2011/013165 JP 2014-183348 A

  Each node that constructs the ad hoc network communicates with each other, so that a frame for collecting route information (route collection frame) is transmitted from the transmission origin node (origin node) to the target node while being repeatedly relayed. Is done. Each time a route collection frame passes through a relaying node, route information is accumulated and added. When the route collection frame finally returns to the origin node, the origin node can acquire route information between the origin node and the target node.

  However, if the path collection frame disappears in the middle due to the occurrence of a communication failure and does not return to the origin node, the origin node cannot obtain any path information between the origin node and the target node. Therefore, it is not possible to follow up and identify the route where the communication failure has occurred.

  According to one aspect of the present invention, a technique for supporting a follow-up survey on a route when a communication failure occurs is provided.

  In one aspect of the present invention, a node device included in a plurality of node devices constructing a communication network from a data transmission source to a data transmission destination is caused to execute the following process. The node device receives the communication information transmitted from the other node device, and adds the communication information obtained by adding the identification information of the subsequent node device in the communication path of communication to the received communication information to the previous node in the communication path. The data is transmitted to the device and the subsequent node device.

  According to one aspect of the present invention, it is possible to support a follow-up survey on a route when a communication failure occurs.

An example of the trace route operation in the mesh-like ad hoc network in the fourth technology will be shown. An example of the trace route operation in the fourth technique when the number of hops is large is shown. An example of the node apparatus in this embodiment is shown. An example of the trace route operation in this embodiment will be described. The operation sequence corresponding to FIG. 4 is shown. An example of the trace route operation when the number of hops is large in this embodiment will be described. The example of the format of the ad hoc control data frame in this embodiment is shown. It is a hardware configuration example of a node in the present embodiment. It is an example of the functional block diagram of the node regarding the frame transmission / reception in this embodiment. An example of the link table in this embodiment is shown. An example of the routing table in this embodiment is shown. An example of the TND routing table in this embodiment is shown. An example of updating the TND routing table in the present embodiment is shown. 6 shows a transmission processing flow of a route collection frame (for forward route) of a starting node in the present embodiment. 6 shows a reception processing flow of a return frame of a start node in the present embodiment. 6 shows a reception processing flow of a route collection frame (for return route) of an origin node in the present embodiment. The processing flow when the reception waiting time of the route collection frame (for return route) of the origin node in this embodiment times out is shown. 5 shows a flow of a relay node route collection frame (for forward route) reception process in the present embodiment. 6 shows a reception processing flow of a return frame of a relay node in the present embodiment. 6 shows a reception processing flow of a backtrack frame of a relay node in the present embodiment.

  For example, the above-described fourth technology has a trace route function that can confirm the route through which data is communicated in an ad hoc network autonomously constructed by each node. In this trace route function, each relaying node adds its own route information to the route collection frame transmitted by the transmission origin node and transfers it. As a result, it is possible to identify the information of the node that has passed between the transmission origin node and the final destination destination node. Even when route switching occurs due to transmission failure, it is possible to acquire route information including information on the route switching.

  With the trace route function, route information can be acquired when the route collection frame returns to the transmission origin node.

  However, in a wireless communication environment where the situation changes every moment due to various external factors, a communication failure may temporarily occur in a shorter period than the control message (HELLO) periodically transmitted and received between nodes. There is sex. In this case, since autonomous route information change is not performed, if the route collection frame is lost during the route, the route collection frame may not return to the transmission origin node.

  In this case, the transmission origin node cannot acquire route information up to the middle. In such a case, the failure path is investigated by searching for the maintenance person using ping or the like, and it takes time to maintain the communication environment. In addition, a delay in the maintenance of the communication environment may cause a decrease in the arrival rate of business data such as meter reading.

  FIG. 1 shows an example of a trace route operation in a mesh-like ad hoc network in the fourth technique. Node devices (hereinafter referred to as “nodes”) A to E are communication terminals equipped with wireless ad hoc communication technology.

  First, the trace route operation when the route information can be acquired will be described with reference to FIG. FIG. 1A illustrates a case where the transmission origin node A transmits a route collection frame to the target node E. Here, route collection frames are transmitted and received between the nodes. Each time the relay node passes, the route collection frame is given route information indicating whether transmission is possible from the relay node to another adjacent relay node.

  (A1) The node A assigns route information in which “success” is set in “transmission result for node B” to the route collection frame, and transmits the route collection frame to node B. As a result, it is assumed here that transmission to the node B has failed.

  (A2) The node A detects a failure in transmission of the route collection frame addressed to the node B, and changes the “transmission result addressed to the node B” of the route collection frame to “failure”. After that, the node A assigns route information in which “success” is set in “transmission result for node C” to the route collection frame, and transmits the route collection frame to node C. Assume that transmission of a route collection frame from node A to node C is normally performed.

  (A3) The node C assigns the route information in which “success” is set in “transmission result for node D” to the received route collection frame, and transmits the route collection frame to node D. Assume that transmission of a route collection frame from node C to node D is normally performed.

  (A4) The node D assigns the route information in which “success” is set in “transmission result for node E” to the received route collection frame, and transmits the route collection frame to node E. As a result, it is assumed here that transmission to the node E has failed.

  (A5) The node D detects a transmission failure of the route collection frame addressed to the node E, and changes the “transmission result addressed to the node E” of the route collection frame to “failure”. Thereafter, the node D assigns the route information set to “success” to the “transmission result addressed to the node C” to the route collection frame, and transmits the route collection frame to the node C (backtrack). It is assumed that transmission of the route collection frame from the node D to the node C is normally performed.

  (A6) The node C adds the route information in which “success” is set in the “transmission result addressed to the node A” to the received frame, and transmits the route collection frame to the node A. Assume that transmission of a route collection frame from node C to node A is normally performed.

  Next, the trace route operation when the route information cannot be acquired will be described with reference to FIG.

  (B1) The node A assigns route information in which “success” is set in “transmission result for node B” to the route collection frame, and transmits the route collection frame to node B. As a result, it is assumed here that transmission to the node B has failed.

  (B2) Node A detects a failure in transmission of the route collection frame addressed to Node B, and changes the “transmission result addressed to Node B” of the route collection frame to “failure”. After that, the node A assigns route information in which “success” is set in “transmission result for node C” to the route collection frame, and transmits the route collection frame to node C. Assume that transmission of a route collection frame from node A to node C is normally performed.

  (B3) The node C assigns the route information in which “success” is set in “transmission result for node D” to the received route collection frame, and transmits the route collection frame to node D. Assume that transmission of a route collection frame from node C to node D is normally performed.

  (B4) The node D attaches the route information in which “success” is set in the “transmission result for node E” to the received route collection frame, and transmits the route collection frame to the node E. As a result, it is assumed here that transmission to the node E has failed.

  (B5) The node D detects a transmission failure of the route collection frame addressed to the node E, and changes the “transmission result addressed to the node E” of the route collection frame to “failure”. In this case, since the path to the target node E stops before reaching the target node E, the traveling direction of the path collection frame is changed from the target node to the transmission origin node (backtrack). . Therefore, the node D assigns the route information set to “success” in the “transmission result addressed to the node C” to the route collection frame, and transmits the route collection frame to the node C. As a result, it is assumed here that transmission to node C has failed. Then, the node A cannot receive the route information added in (B3) and (B4), and the route collection frame (backtrack frame) disappears.

  (B6) The node A detects the timeout of the reception waiting time of the backtrack path collection frame. In this case, the node A cannot obtain any route information and fails in route collection.

  FIG. 2 shows an example of the trace route operation in the fourth technique when the number of hops is large. In FIG. 2, the route from node A to node Z is desired to be acquired, but the route collection frame can reach only node X, and the route collection frame (backtrack frame) is lost between nodes F to E. An example of

  In FIG. 2, it is assumed that the node A wants to confirm the route from the node A to the node Z, but the route collection frame reaches only the node X. That is, the node X transmits a route collection frame addressed to the node Y, but the transmission fails (B11).

  When one communication path is disconnected, the node X tries to transmit to the node Y through another communication path (B12). It is assumed that the route collection frame does not reach the node Y and does not reach any other node (Y ′, Y ″) (not shown). As a result, an acknowledgment (ACK) frame for the transmission of the route collection frame may be received. Since it is not possible, when detecting a timeout due to exceeding the ACK reception waiting time, the node X transmits a path collection frame to the transmission origin node (backtrack) (B13).

  Here, communication may be disabled due to changes in radio wave conditions, etc., since time has passed since the previous communication. It is assumed that the route collection frame (backtrack frame) is lost due to a communication failure between the nodes EF (B14). If the backtrack frame is not returned, the node E does not know the communication path at all, so it is difficult to identify where the communication failure has occurred.

  According to FIG. 2, as the number of hops increases, the elapsed time T1 from the previous communication (frame transmission from the node A toward the node Z) to the return of the backtrack frame increases. As a result, there is a high possibility that a change in the radio wave situation will occur, and a possibility that a communication failure will occur. The same thing can happen in any of the nodes B to Y. Therefore, as the number of hops increases, the possibility that the backtrack frame is lost correspondingly increases.

  As described above, when a communication failure occurs such that a frame is lost in the middle of the route, the failure occurrence area cannot be narrowed down at all. Therefore, the maintenance person needs to perform the following investigation. The maintenance person goes near each node, refers to the information in the link table and routing table, and investigates the route from the transmission source to the final destination. ).

  Also, based on the investigated route information, the investigation path such as trace route and ping is used for each node a plurality of times to narrow down the path causing the problem. In addition, since these investigations can be performed only by a maintenance person who understands the details of the operation of ad hoc routing, and cannot be performed by any maintenance person, the efficiency of investigation tends to deteriorate.

  Therefore, in this embodiment, each relay node transmits the route data to the next hop node and transmits the route data at that time to the transmission origin node of route collection. The transmission origin node can know to which node the route collection frame has arrived, and even if the frame is lost on the way, it is possible to obtain route information before the loss.

  As a result, each node on the route transmits the same frame (turnback frame) as the route collection frame to the node at the transmission origin of the route collection, so that the node at the transmission origin collects the route to each node on the route. It is possible to grasp the arrival status of the frame.

  In addition, by utilizing the management information for managing the source node between adjacent nodes, the loopback frame is transferred to the source node by following the same route as the route collection frame. A certain route can be used.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings. First, terms used in this specification will be described.

  A “frame” refers to a data unit based on a protocol used in an ad hoc network. “Frame” includes, for example, “hello message frame” and “data frame”, but is not limited thereto.

  A “hello message frame (HELLO message frame)” is a type of control frame for communicating control information, and is transmitted from a node device to another node device to confirm each other's presence and state. It refers to a special frame. Note that the HELLO message frame may be simply referred to as a HELLO message.

  “Data frame” refers to data that the network intends to transmit (from the start node to the goal node).

  “Global Destination (GD)” refers to a node ID as a final destination in an ad hoc network. In the present specification, the GD may be referred to as a “global destination address”.

  “Global Source (GS)” refers to a node ID that is the first transmission source in an ad hoc network. In the present specification, GS may be referred to as “global source address”.

  “Local Destination (LD)” is a destination node ID of a frame between adjacent nodes that relay a frame transmitted from the node of “global source address (GS)” to the node of “global destination address (GD)”. Refers to that. In this specification, the LD may be referred to as a “local destination address”.

  “Local Source (LS)” means a frame transmission source node between adjacent nodes that relay a frame transmitted from a node of “global source address (GS)” to a node of “global destination address (GD)” Refers to ID. In the present specification, LS may be referred to as “local source address”.

  FIG. 3 shows an example of a node device in the present embodiment. The node device 1 is a node device included in a plurality of node devices that construct a communication network from a data transmission source to a data transmission destination. The node device 1 includes a reception unit 2 and a transmission unit 3. An example of the node device 1 is a node 11 (FIG. 9). An example of a communication network is an ad hoc network.

  The receiving unit 2 receives communication information transmitted from other node devices. An example of the receiving unit 2 is the receiving unit 26 (FIG. 9).

  The transmission unit 3 transmits communication information obtained by adding identification information of the subsequent node device in the communication path to the received communication information to the preceding node device and the subsequent node device in the communication path. More specifically, the transmission unit 3 transmits the return information, which is communication information transmitted to the preceding node device, to the preceding node device with the transmission source as the starting point as the final destination. An example of the transmission unit 3 includes a routing unit 23 and a transmission unit 27. An example of the identification information of the subsequent node device is the node ID of the subsequent node.

  By configuring in this way, the node of the data transmission source (transmission origin) can acquire the route information on the way to the node reached by the relay regardless of the reception of the route collection frame, so that a communication failure occurs. In this case, it becomes easy to follow up the route.

  The node device 1 further includes a storage unit 4. When the node device 1 receives the communication information from the preceding node device, the node device 1 holds the identification information of the preceding node device in the storage unit 4. As an example of the storage unit 4 that holds the identification information of the node device in the previous stage, there is the RAM 14 or the nonvolatile memory 15 (FIGS. 8 and 9) that stores the transmission source (LS) node information 34. At this time, when receiving the return information from the succeeding node device, the transmitting unit 3 transmits the return information to the preceding node device using the retained identification information.

  By configuring in this way, the return information follows the same route as the forward route and is transferred to the origin node, so that it is possible to use a route that has been used most recently.

  The node device 1 further includes a specifying unit. The specifying unit 5 specifies the communication status between the node devices on the communication path based on the reception confirmation information for the transmitted communication information received from the node device at the subsequent stage. An example of the specifying unit is the routing 23.

  With this configuration, it is possible to monitor the state of the communication path in the network.

  Further, the receiving unit 2 receives communication information from the subsequent node device. Then, the transmission unit 3 transmits the communication information obtained by adding the identification information of the preceding node device to the communication information received from the succeeding node device to the preceding node device.

  With this configuration, each node device can relay a route collection frame (return route).

The details of this embodiment will be described below.
FIG. 4 shows an example of the trace route operation in the present embodiment. FIG. 5 shows an operation sequence corresponding to FIG. 4 and 5, it is assumed that the node A starts to collect the route between the nodes A and E (outbound) to the node E. Here, route collection frames are transmitted and received between the nodes. Each time the relay node passes, the route collection frame is given route information indicating whether transmission is possible from the relay node to another adjacent relay node.

  (S1) The node A assigns the route information in which “success” is set in the “transmission result addressed to the node B” to the route collection frame, and transmits the route collection frame to the node B. As a result, it is assumed here that transmission to the node B has failed.

  (S2) Node A detects a failure in transmission of the route collection frame addressed to Node B, and changes the “transmission result addressed to Node B” of the route collection frame to “failure”. After that, the node A assigns route information in which “success” is set in “transmission result for node C” to the route collection frame, and transmits the route collection frame to node C. Assume that transmission of a route collection frame from node A to node C is normally performed.

  (S3) When the node C receives the route collection frame from the node B, the node C gives route information in which “success” is set in the “transmission result for node D” to the received route collection frame. Node C transmits a route collection frame to which the route information is added to node D (assuming that transmission of the route collection frame from node C to node D was normally performed).

  At this time, the node C transmits a route collection frame (turnback frame) with the route information added to the transmission source node A (transmission of the route collection frame from the node C to the node A is normally performed). Suppose). Note that route information is not given to the return frame at the relay node that passes to the final destination node. Node A analyzes the received loopback frame to determine that node C has transmitted to node D.

  (S4) When the node D receives the route collection frame from the node C, the node D gives route information in which “success” is set in the “transmission result for node E” to the received route collection frame. The node D transmits a route collection frame to which the route information is added to the node E (as a result, it is assumed here that transmission to the node E has failed).

  At this time, the node D transmits a route collection frame (return frame) to which the route information is added to the transmission source A via the node C (the transmission of the route collection frame from the node D to the node A is normal). ). Note that route information is not given to the return frame at the relay node that passes to the final destination node.

  Node A knows that node D has transmitted to node E by analyzing the received return frame. Node A arrives because it can overwrite the arrival information by receiving the route collection frame in (S4) even if it cannot receive the route collection frame for some reason (communication failure, etc.) in (S3). It becomes possible to confirm.

  (S5) The node D detects a transmission failure of the route collection frame addressed to the node E, and changes the “transmission result addressed to the node E” of the route collection frame to “failure”. Thereafter, the node D assigns the route information set to “success” to the “transmission result addressed to the node C” to the route collection frame, and transmits the route collection frame to the node C (backtrack). As a result, it is assumed here that transmission to node C has failed. In the case of transmitting the backtrack, the return frame is not transmitted.

  As a result, the route collection frame disappears while node A obtains the route information in (S3) and (S4). Here, the transmission to the node C (backtrack) in (S5) detects the failure of transmission to the node E in (S4) after transmitting to the node C or node E in (S4). This is done after the time has elapsed. Therefore, there is a high possibility that the communication environment will change before and after transmission to node C in (S4) and transmission to node C in (S5), and transmission to node C in (S4) has succeeded. (S5) It is fully conceivable that transmission addressed to C fails.

  4 and 5, since the number of hops is small, the occurrence of a change in the communication environment is limited to the time zone between (S4) C-addressed transmission and (S5) C-addressed transmission, but the hop count is large. If this is the case, the target time zone will be more widened. An example in the case of multi-hop will be described with reference to FIG.

  (S6) The node A detects a timeout of the reception waiting time of the path collection frame (return path).

  Based on the information obtained in S3 and S4, transmission was successful from node A to node C to node D, and a timeout in reception waiting time was detected in S6 (a route collection frame from node E was not received). Therefore, node A can make the following determination. That is, node A knows that transmission failed from node D to node E.

  The above example is described based on an example in which the number of hops is small. However, in actual operation, it is assumed that the transfer by the relay node takes several tens of hops. Therefore, the path collection frame itself that each node on the path returns to the node that is the transmission origin of the path collection may be lost. However, since the return frame uses the route with the latest communication results, it is unlikely that all the return frames will be lost, and by analyzing each return frame that has arrived at the source node, the route to the final destination is analyzed. Can be traced.

  Note that the trace route frame is intermittently transmitted for maintenance as opposed to the normal frame transmission. Thereby, for example, it can be used without affecting the transmission / reception of a normal frame for collecting sensor values obtained by sensors mounted on the nodes.

  FIG. 6 shows an example of the trace route operation when the number of hops is large in the present embodiment. In FIG. 6, it is assumed that node A wants to obtain a route from node A to node Z, but the packet can only reach node X, and the backtrack packet is lost between nodes F to E. .

  First, the node A adds route information (transmission result for node B = success) to the route collection frame. The node A transmits a route collection frame with the route information added to the node B (S11).

  When the node B receives the route collection frame from the node A, the node B adds route information (transmission result for node C = success) to the received route collection frame. Node B transmits a route collection frame to which route information is added to node C (S12). At this time, the node B transmits the same frame (turned frame) as the route collection frame transmitted to the node A to the node A (S12a).

  When the node C receives the route collection frame from the node B, the node C adds route information (transmission result for node D = success) to the received route collection frame. The node C transmits a route collection frame to which the route information is added to the node D (S13). At this time, the node C transmits the same frame (turnback frame) as the route collection frame transmitted to D to the node A (S13a).

  Similarly, after that, when each node receives the route collection frame, each node adds route information to the received route collection frame, and transmits the route collection frame with the route information added to the next pop node (S14 to S20). ). At the same time, each node transmits the same frame (turnback frame) as the route collection frame transmitted to the node of the next hop to node A (S14a to S20a).

  When the node X receives the route collection frame from the node W, it adds route information (transmission result for node C = success) to the received route collection frame. The node X transmits the route collection frame with the route information added to the node Y (S21). However, in this example, it is assumed that transmission of the route collection frame to the node Y has failed. At this time, the node X transmits the same frame (turnback frame) as the route collection frame transmitted to the node A to the node A (S21a).

  If one route is disconnected, the node X confirms with another route (S21 ′, S21 ″). The transmitted route collection frame does not reach the node Y and is addressed to the other node (Y ′, Y ″). Node X, after detecting the timeout, adds the route information (transmission result for node W = success) to the received route collection frame, and node X adds the route collection frame with the route information added thereto. , Transmitted to the node W (backtrack) (S22) From S22 onward, the path collection frame is referred to as a backtrack frame.

  When the node W receives the backtrack frame from the node X, the node W adds path information (transmission result for node V = success) to the received backtrack frame. The node W transmits the backtrack frame with the route information added to the node V (S23).

  Similarly, after that, each node, when receiving the backtrack frame, adds route information to the received backtrack frame, and transmits the backtrack frame with the route information added to the next pop node (S24 to S27). ).

  Here, communication may be disabled due to changes in radio wave conditions, etc., since time has passed since the previous communication. It is assumed that the backtrack frame is lost due to a communication failure between the nodes EF (S28).

  However, even if the backtrack does not return in this manner, the transmission source node A can acquire the route information up to the middle by the return frame transmitted in S12a to S21a. You can focus on the area.

  According to FIG. 6, even if a frame disappearance occurs in the period T2, the transmission source node can confirm how far the route search frame has reached by receiving the return frame. As a result, it is possible to narrow down the paths in which the route collection frame is lost.

(Example)
FIG. 7 shows an example of the format of an ad hoc control data frame in the present embodiment. The ad hoc control data frame (hereinafter referred to as “data frame”) includes an ad hoc header, a security header, a data header, an ad hoc message (AM) header, and an ad hoc message.

  The ad hoc header includes information such as a local destination address (LD), a local transmission source address (LS), a type, and a frame size. Note that the Hello frame also includes an ad hoc header, and the data frame and the Hello frame are identified by the type value. For example, type = 1 is set in the data frame, and type = 0 is set in the Hello frame.

  The data header includes a global destination address (GD), a global source address (GS), a frame identifier (FID), an HTL (Hop to live), a hop number, and the like. The frame identifier is an identification number assigned for each ad hoc frame. HTL is a value representing the expiration date of the data frame. Each time a frame is transferred between adjacent nodes, the HTL value is decremented by one.

  The AM header includes a type and a subtype. The type is information specifying the function or usage type of the ad hoc control data frame. For example, when “Trace Route” is set as the type, the data frame has a function related to collection of route information and the like.

  The subtype is information that further specifies the function or use set in the “type”. For example, when “0x00 (collection)” is set in the subtype, this indicates that the data frame is a route collection frame used for collecting route information. When “0x02 (turned back)” is set in the subtype, this indicates that the data frame is a turned back frame.

  The ad hoc message corresponds to a data payload. In the ad hoc message, transmission results for the next-hop node are accumulated and set.

  FIG. 8 is a hardware configuration example of a node in the present embodiment. The node 11 includes a CPU (Central Processing Unit) 12, a wireless communication interface (I / F) 13, a RAM (Random Access Memory) 14, and a nonvolatile memory 15. The CPU 12 is connected to the wireless communication I / F 13, the RAM 14, and the nonvolatile memory 15 through a predetermined bus.

  The CPU 12 is responsible for various calculation processes. CPU12 reads the program which implement | achieves the process later mentioned stored in the non-volatile memory 15 grade | etc., And executes the said program. The nonvolatile memory 15 is a semiconductor memory such as a ROM (Read Only Memory) or a readable / writable SSD (Solid State Drive). The RAM 14 is a volatile memory that temporarily holds data.

  The wireless communication I / F 13 is hardware that performs processing for wireless LAN (Local Area Network) connection. The wireless communication I / F 13 includes, for example, an antenna, an ADC (Analog-to-Digital Converter), a DAC (Digital-to-Analog Converter), a modulator, a demodulator, and the like.

  The node 11 is also equipped with a rechargeable battery as a power source for supplying power to these electronic components to operate them. Although not shown, the node 11 includes a clock or timer for timing.

  A program that realizes processing described in an embodiment described below may be stored in a storage device such as the nonvolatile memory 15 via a communication network from the program provider side. In addition, a program that realizes processing described in an embodiment to be described later may be stored in a commercially available portable storage medium. In this case, the portable storage medium may be set in the reading device, and the program may be read and executed by the CPU 12.

  FIG. 9 is an example of a functional block diagram of a node related to frame transmission / reception in the present embodiment. The non-volatile memory 15 stores a routing table 31, a link table 32, a target node (TND) routing table 33, transmission source (LS) node information 34, and the like.

  In this embodiment, the routing table 31, the link table 32, the TND routing table 33, and the transmission source (LS) node information 34 are stored in the non-volatile memory 15. However, the present invention is not limited to this. Also good.

  The wireless communication I / F 13 includes a reception unit 26 and a transmission unit 27, and performs processing for performing communication with other nodes. The receiving unit 26 receives a frame signal transmitted to the node 11 and outputs the received signal to the frame reception processing unit 21.

  The CPU 12 reads a program stored in the nonvolatile memory 15 and functions as a HELLO control unit 25, a frame transmission processing unit 22, a frame reception processing unit 21, a routing unit 23, and an application processing unit 24.

  The frame reception processing unit 21 converts the signal input from the reception unit 26 into a frame so that the routing unit 23 can process the signal. The frame obtained by the conversion of the frame reception processing unit 21 includes a route collection frame, a control frame other than the route collection frame, a data frame storing user data, and the like. The frame reception processing unit 21 outputs the obtained frame to the routing unit 23.

  When a frame addressed to the node 11 is input from the routing unit 23, the application processing unit 24 processes the input frame with an application program. Further, the application processing unit 24 can generate a data frame to be transmitted to another node 11 by processing of the application program. The application processing unit 24 outputs the generated data frame to the routing unit 23.

  The routing unit 23 determines whether the destination (LD) of the input frame is destined for the node on which the routing unit 23 is mounted or other nodes. When the destination (LD) of the frame is destined for the node on which the routing unit 23 is mounted, the routing unit 23 uses the information registered in the routing table 31 to select any adjacent node (LD ).

  The routing unit 23 registers the transmission source of the received HELLO message in the routing table 31 based on the ad hoc header included in the input frame. Further, the node information included in the received HELLO message is used to calculate the route quality and the communication quality of the link between nodes, and the result is registered in the routing table 31 and the link table 32. The routing unit 23 controls the transmission unit 27 so as to transmit a frame including information registered in the routing table 31 and the link table 32.

  When receiving the route collection frame, the routing unit 23 extracts a local source address (LS) from the route collection frame, and stores the extracted local source address (LS) as source (LS) node information 34 in the nonvolatile memory 15. Store.

  The routing unit 23 generates a route collection frame in which a transmission result addressed to the next hop node (default value = success) is added to the received next route collection node (next stage). At the same time, the routing unit 23 generates a return frame having the same route information as that of the generated route collection frame, addressed to the preceding hop node. The generated frame is transmitted via the transmitter 27.

  After sending a route collection frame with the transmission result (default value = success) addressed to the next hop node to the next hop (subsequent stage) node, depending on whether an acknowledgment (ACK) frame corresponding to the transmission is received Thus, the routing unit 23 identifies the communication status with the adjacent node. That is, when the reception confirmation (ACK) frame is received, the routing unit 23 specifies that the communication with the adjacent node is successful, that is, the communication state is good. On the other hand, when the reception confirmation (ACK) frame cannot be received, the routing unit 23 specifies that the communication with the adjacent node has failed, that is, the communication status is bad.

  When receiving a return frame from another node, the routing unit 23 controls to transfer the return frame to the LS stored as the transmission source (LS) node information 34.

  The HELLO control unit 25 uses the information registered in the routing table 31 to generate a HELLO message frame and outputs it to the frame transmission processing unit 22. The HELLO control unit 25 can generate a hello frame including information regarding the route included in the routing table 31.

  The frame transmission processing unit 22 controls the transmission unit 27 to transmit a frame.

  FIG. 10 shows an example of a link table in the present embodiment. Each node has a link table 31 for nodes adjacent to itself. A node adjacent to itself indicates a node that performs ad hoc communication with itself. Each node, when receiving a Hello message frame from a node adjacent to itself, generates a link table 31 for the node that has transmitted the Hello message frame.

  The link table 31 includes data items of “local source address (LS)”, “aging timer”, and “HELLO and received radio wave related parameters”.

  The “local source address (LS)” stores the source address of the Hello message frame, that is, the local source address included in the ad hoc header of the Hello message frame received from the adjacent node.

  The “aging timer” is information for adjusting the timing of deleting the link table 31, and a default value is set when the link table 31 is created.

  In “HELLO and received radio wave related parameters”, information included in various headers of a Hello message frame received from an adjacent node, received radio wave intensity (or communication quality), and other received radio wave related parameters are stored. Each node transmits a Hello message frame including information related to the communication quality of radio waves received from other nodes. The node refers to the Hello message frame received from another node device, calculates the communication quality of the adjacent node, and stores information related to the calculated reception strength (or communication quality) in the “HELLO and received radio wave related parameters”. Hold.

  FIG. 11 shows an example of a routing table in the present embodiment. The routing table 32 is a table that holds routing information for adjacent nodes managed in units of global destination addresses (GD), and is generated for each global destination address. Each node generates a routing table 32 using a link table 31 generated from a Hello message frame received from an adjacent node.

  The routing table 32 can record one or more arbitrary numbers of local destination addresses (LD) for one global destination address (GD). The routing table 32 records, for each combination of global destination and local destination, information indicating the quality of the route calculated using, for example, the number of hops of the route and the received radio wave strength of each link included in the route. Can do.

  FIG. 12 shows an example of the TND routing table in the present embodiment. The TND routing table 33 includes data items of “global destination address (GD)”, “route collection start time”, and “route route information”.

  The “global destination address (GD)” stores the ID of the target node. The “route collection start time” stores the date and time when the route collection frame is transmitted.

  The “intermediate route information” stores intermediate route information obtained from the return frame transmitted from the relay node that has received the route collection frame. More specifically, the intermediate route information is the accumulation of transmission results for the next hop node assigned by each relay node from the node adjacent to the source transmission source (GS) node to the node that transmitted the return frame. Information.

  FIG. 13 shows an example of updating the TND routing table in the present embodiment. In S3 of FIG. 4, the node C transmits a return frame including the transmission results for the nodes B, C, and D to the node A that is the transmission source. When node A receives the loopback frame, node A registers it in the TND routing table as shown in FIG.

  Next, in S4 of FIG. 4, the node D sends nodes B, C, D. A return frame including a transmission result for E is transmitted. When the node A receives the return frame, the node A updates the TND routing table as shown in FIG.

  In this case, in S5 and S6 in FIG. 4, the node A cannot receive the route collection frame (return route). However, even if node A detects a reception timeout, it can be seen that the route collection frame (return route) has not been received, and the TND routing table 33 has reached node D because of the state shown in FIG. .

  Next, processing of a node (starting node) serving as a starting point for transmitting a route collection frame to the target node will be described with reference to FIGS. The origin node and the target node can be any nodes.

  FIG. 14 shows a transmission processing flow of a route collection frame (outbound route) of the origin node in the present embodiment. The origin node acquires route collection instruction information for collecting route information to the target node transmitted from the user's terminal by the user's operation (S31). In the route collection instruction information, the node ID of the target node is specified.

  The origin node acquires an adjacent node that can be transmitted to the target node from the routing table 32 (S32). Here, the origin node acquires from the routing table 32 the LD (node ID of the adjacent node) included in the entry having the designated target node as GD. When a plurality of LDs can be acquired, the origin node acquires, for example, the LD with the best communication quality.

  In S32, when the destination adjacent node can be acquired from the routing table 32 (“YES” in S33), the origin node generates a route collection frame (for forward route). Here, the origin node sets “type = Trace Route” and “subtype =“ 0x00 ”(collection)” in the AM header of the generated data frame. Further, the originating node gives a transmission result (default value = “success”) addressed to the destination adjacent node (next pop node) to the route collection frame (for forward route) (S34).

  The origin node transmits the route collection frame to which the transmission result (default value = “success”) is given to the adjacent node (next pop node) of the transmission destination (S35). At this time, the origin node holds a frame identifier included in the data header of the path collection frame (for forward path) in order to determine the path collection frame (return path) corresponding to the path collection frame (for forward path).

  At this time, the origin node measures the predetermined time until receiving the acknowledgment (ACK) frame notifying that the destination adjacent node (next pop node) has received the transmitted route collection frame. A reception waiting timer is started (S36).

  In addition, the origin node starts a timer that measures a waiting time until a route collection frame (for return route) is received (S37).

  When the ACK frame for the transmission of the route collection frame is not received from the adjacent node within the predetermined time measured by the ACK reception waiting timer (“NO” in S38), the originating node detects the timeout of the ACK reception waiting time (S39). In this case, the originating node updates the transmission result addressed to the next pop node assigned to the route collection frame to “failure” in S34 (S40).

  In S38, when the ACK frame for the transmission of the route collection frame is received from the adjacent node within the predetermined time measured by the ACK reception waiting timer (“YES” in S38), the originating node sets the ACK reception waiting timer. Stop (S41). Then, the starting point No enters a state of waiting for receiving a route collection frame (for return route) (S42).

  In S33, when the adjacent node of the transmission destination cannot be acquired from the routing table 32 (“NO” in S33), the origin node transmits a response indicating a route collection failure to the user terminal as a response to the route collection instruction. (S43).

  FIG. 15 shows a reception processing flow of the return frame of the origin node in the present embodiment. The origin node receives the data frame (S51). The origin node determines whether the received data frame is a folded frame. When “type = Trace Route” and “subtype =“ 0x02 ”(return)” in the AM header of the received data frame, the origin node determines that the received data frame is a return frame, and so on. Perform the process.

  When the return frame is received, the origin node determines whether or not the path information is being collected (S52). When the path collection frame (for return path) reception waiting timer (S37 in FIG. 14) is activated, the origin node determines that the path information is being collected.

  When the route information is not being collected (“NO” in S52), the originating node performs the process of S54.

  When the path information is being collected (“YES” in S52), the origin node updates the TND routing table 33 by using the midway path information included in the return frame as described with reference to FIG. (S53).

  The origin node waits to receive a route collection frame (for return route) (S54).

  FIG. 16 shows a reception processing flow of the route collection frame (for return route) of the origin node in this embodiment. The origin node receives the data frame (S61). The origin node determines whether the received data frame is a route collection frame (for return route). When the frame identifier included in the data header of the received data frame is the frame identifier held in S35 of FIG. 14, the originating node determines that the received data frame is a path collection frame (for return path), and S62 Perform the following processing.

  When the route collection frame (for return route) is received, the origin node determines whether or not the route information is being collected (S52). When the path collection frame (for return path) reception waiting timer (S37 in FIG. 14) is activated, the origin node determines that the path information is being collected.

  When the route information is not being collected (“NO” in S62), the starting node performs the process of S67.

  When the path information is being collected (“YES” in S62), the originating node stops the path collection frame (for return path) reception waiting timer (S63).

  The origin node clears the TND routing table 33 (S64). The origin node extracts information about the relay node that relays communication between the origin node and the target node from the received route collection frame (for return route). The origin node generates route information for the target node based on the extracted information about the relay node (S65). The origin node transmits the generated route information to the user terminal as a response to the route collection instruction (S66).

  The origin node waits to receive a route collection frame (for return route) (S67).

  FIG. 17 shows a processing flow when the reception wait time of the route collection frame (for return route) at the origin node in this embodiment times out.

  When the time measured by the path collection frame (for return path) reception waiting timer started in S37 of FIG. 14 exceeds a predetermined time, the origin node detects a timeout of the path collection frame (for return path) reception wait time (S71). ).

  The origin node determines whether or not the path information is being collected (S72). When the path collection frame (for return path) reception waiting timer (S37 in FIG. 14) is activated, the origin node determines that the path information is being collected.

  When the route information is not being collected (“NO” in S72), the starting node ends this flow.

  When the path information is being collected (“YES” in S72), the origin node acquires a TND routing table for the target node (S73). In response to the route collection instruction, the origin node transmits “GD”, “route collection disclosure time”, and “route route information” in the acquired TND routing table to the user terminal (S74).

  Next, processing of a node (relay node) that relays communication between the origin node and the target node will be described with reference to FIGS.

  FIG. 18 shows a flow of a relay node route collection frame (for forward route) reception process in this embodiment. The relay node receives the data frame (S81). The relay node determines whether the received data frame is a path collection frame (for forward path). When “type = Trace Route”, “subtype =“ 0x00 ”(collection)” in the AM header of the received data frame and the same frame identifier as that of the frame identifier is not held, the origin node Process. That is, the origin node determines that the received data frame is a path collection frame (for forward path), and performs the processing from S82 onward.

  When the path collection frame (for forward path) is received, the relay node transmits an ACK frame to the adjacent node (transmission source (LS)) that transmitted the path collection frame (for forward path) (S82).

  The relay node holds the node ID of the adjacent node (source (LS)) as source (LS) node information 34 (S83).

  The relay node acquires an adjacent node that can be transmitted to the target node from the routing table 32 (S84). Here, the relay node acquires from the routing table 32 the LD (node ID of the adjacent node) included in the GD entry corresponding to the GD included in the received path collection frame (for forward path). When a plurality of LDs can be acquired, the relay node acquires, for example, the LD with the best communication quality.

  In S84, when the destination adjacent node can be acquired from the routing table 32 (“YES” in S85), the relay node generates a transfer path collection frame (for forward path). Here, the relay node sets “type = Trace Route” and “subtype =“ 0x00 ”(collection)” in the AM header of the generated data frame. In addition, the originating node gives a transmission result (default value = “success”) addressed to the destination adjacent node (next pop node) to the generated path collection frame (for forward path) (S86).

  The relay node transmits the route collection frame to which the transmission result (default value = “success”) is assigned to the adjacent node (next pop node) of the transmission destination (S87). At this time, the relay node holds a frame identifier included in the data header of the path collection frame (for forward path) in order to determine the path collection frame (return path) corresponding to the path collection frame (for forward path).

  Further, the relay node generates a return frame, and transmits the generated return frame to the transmission source (LS) held in S83 (S88). Here, the relay node generates the return frame as follows. The relay node acquires the node ID of the origin node (GS) from the route collection frame generated in S86 and given the transmission result (default value = “success”). In the route collection frame, the relay node sets the node ID of the origin node in GD, sets the transmission source (LS) acquired from the node information 34 in LD, and sets “type = Trace Route”, “sub” in the AM header. Set type = “0x02” (wrapping).

  The relay node is an ACK reception waiting timer that measures a predetermined time until the reception adjacent node (next pop node) receives an acknowledgment (ACK) frame notifying that the transmitted route collection frame has been received. Is activated (S89).

  When the ACK frame for the transmission of the route collection frame in S87 is not received from the adjacent node within the predetermined time measured by the ACK reception waiting timer (“NO” in S90), the relay node determines the ACK reception waiting time. A timeout is detected (S91). In this case, the relay node determines that the communication status with the adjacent node is poor, and updates the transmission result addressed to the next pop node added to the path collection frame in S86 to “failure” (S92).

  In S90, when an ACK frame for transmission of a route collection frame (for forward route) is received from an adjacent node within a predetermined time measured by the ACK reception waiting timer (“YES” in S90), the relay node It is determined that the communication status with the adjacent node is good. In this case, the relay node stops the ACK reception waiting timer (S93).

  In S85, when the adjacent node of the transmission destination cannot be acquired from the routing table 32 (“NO” in S85), the relay node acquires the transmission source (LS) from the transmission source (LS) node information 34 (S94). ).

  The relay node generates a backtrack frame and transmits the generated backtrack frame to the transmission source (LS) acquired from the transmission source (LS) node information 34 (S95). Here, the relay node generates a backtrack frame as follows. The relay node acquires the node ID of the origin node (GS) from the route collection frame received in S81. In the route collection frame, the relay node sets the node ID of the origin node in GD, and sets the transmission source (LS) acquired from the node information 34 in LD.

  In FIG. 18, the processing when the route collection frame (for the forward route) is received has been described, but the case where the route collection frame (for the backward route) is received is the same as that in FIG. 18. That is, in the description of FIG. 18 described above, the route collection frame (for the forward route) may be read as the route collection frame (for the backward route).

  FIG. 19 shows a reception processing flow of the return frame of the relay node in the present embodiment. The relay node receives the data frame (S101). The relay node determines whether the received data frame is a return frame. When “type = Trace Route” and “subtype =“ 0x02 ”(return)” in the AM header of the received data frame, the relay node determines that the received data frame is a return frame, and after S102 Perform the process.

  When the return frame is received, the relay node acquires the transmission source (LS) from the transmission source (LS) node information 34 (S102).

  The relay node sets the transmission source (LS) from the transmission source (LS) node information 34 in the LD of the received return frame. The relay node transmits the return frame to the transmission source (LS) acquired from the transmission source (LS) node information 34 (S103).

FIG. 20 shows a reception processing flow of the backtrack frame of the relay node in this embodiment. The relay node receives the data frame (S111). The relay node determines whether the received data frame is a backtrack frame.
When the frame identifier that is the same as the frame identifier of the data header of the received data frame is held, and the transmission result addressed to the next pop node is set to “failure”, the relay node determines that the received data frame is It is determined that it is a backtrack frame. In that case, the relay node performs the processing after S112.

  When the backtrack frame is received, the relay node acquires the transmission source (LS) from the transmission source (LS) node information 34 (S112).

  The relay node sets the transmission source (LS) from the transmission source (LS) node information 34 in the LD of the received backtrack frame. The relay node transmits the backtrack frame to the transmission source (LS) acquired from the transmission source (LS) node information 34 (S113).

  In FIG. 20, the processing when the backtrack frame is received has been described, but the relay node may execute the flow of FIG. 20 even when the route collection frame (for return route) is received.

  According to this embodiment, each node in the middle of the route relays the frame and transmits a route information frame to the transmission origin. By notifying the arrival to the relay node using this route information frame, even when the frame is lost in the middle, the transmission origin node can obtain the route information up to the middle. As a result, the path where the communication failure has occurred can be immediately identified.

  Therefore, even in the case of a communication failure in which a frame is lost along the route, the event can be monitored in real time, so that the corresponding wireless section can be maintained early. Further, in the present embodiment, it is possible to identify the path that is the cause by performing frame transmission designating the final destination node. Therefore, since it is not necessary to limit to a specific maintenance person, an efficient investigation is possible, and a reduction in the number of investigation steps can be expected.

  The present invention is not limited to the above-described embodiment, and various configurations or embodiments can be taken without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Relay device 2 Receiving part 3 Transmitting part 4 Storage part 5 Identification part 11 Node 12 CPU
13 Wireless communication I / F
14 RAM
DESCRIPTION OF SYMBOLS 15 Nonvolatile memory 21 Frame reception process part 22 Frame transmission process part 23 Routing part 24 Application process part 25 HELLO control part 26 Receiving part 27 Transmission part 31 Routing table 32 Link table 33 TND routing table 34 Source (LS) node information

Claims (7)

To node devices included in a plurality of node devices that construct a communication network from a data transmission source to a data transmission destination,
Receives communication information transmitted from other node devices,
Transmitting the communication information in which the identification information of the subsequent node device in the communication path of the communication is added to the received communication information to the previous node device and the subsequent node device in the communication path;
A route information collection program characterized by causing processing to be executed. In the transmission, the return information that is the communication information transmitted to the preceding node device is transmitted to the preceding node device with the transmission source as a starting point as a final destination. The described route information collection program. In addition to the node device,
When the communication information is received from the upstream node device, the identification information of the upstream node device is stored in a storage device,
The path information collection according to claim 2, wherein when the return information is received from the subsequent node device, the return information is transmitted to the previous node device using the stored identification information. program. In addition to the node device,
A path information collection program characterized by causing a process of specifying a communication status between node apparatuses on the communication path to be executed based on reception confirmation information for the transmitted communication information received from the subsequent node apparatus. In addition to the node device,
When communication information is received from the downstream node device, the communication information obtained by adding identification information of the upstream node device to the communication information received from the downstream node device is transmitted to the upstream node device.
A route information collection program characterized by causing processing to be executed. To node devices included in a plurality of node devices that construct a communication network from a data transmission source to a data transmission destination,
Receives communication information transmitted from other node devices,
The communication information in which the identification information of the subsequent node device in the communication path of the communication is added to the received communication information is transmitted to the subsequent node device, and the data transmission destination is the final destination. To the previous node device in
The route information collection method, characterized in that the final data transmission destination device executes a process of collecting the communication information transmitted from the plurality of node devices. A node device included in a plurality of node devices constructing a communication network from a data transmission source to a data transmission destination,
A receiving unit for receiving communication information transmitted from another node device;
A transmission unit for transmitting communication information obtained by adding identification information of a subsequent-stage node device in the communication path of the communication to the received communication information to the previous-stage node device and the subsequent-stage node device in the communication path;
A node device comprising:

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