JP2005064848A - Method and device for detecting duplicate address in ad hoc network - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device which enable a destination node to detect that an address of the node itself is duplicatively assigned in one network by discriminating a destination sequence number as a sequence number related to the other node having the same address in the case that the destination sequence number is registered in a route request message from a transmission source node which the node communicates with for the first time because of the absence of a communication history in a routing table. <P>SOLUTION: The device includes; a means for analyzing a route request message destined for the node to extract its transmission source address and destination sequence number; a means for discriminating the presence or the absence of a communication history for the transmission source node on the basis of the extracted transmission source address; a duplicate address detection means for detecting the presence of a duplicate address in the case that the communication history for the transmission source node doesn't exist and the destination sequence number is other than a prescribed identifier which is given to an unknown destination sequence number; and a means for returning a route response message when being not capable of detecting the existence of a duplicate address on the basis of the route request message. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a duplicate address detection method and detection apparatus, and more particularly to a duplicate address detection method and detection apparatus capable of detecting a duplicate address in a multi-hop wireless mobile ad hoc network (hereinafter referred to as an ad hoc network).

  In order to detect duplicate addresses, a function for detecting duplicate addresses has been introduced in the routing protocol. For identifying a node in the network, not only an IP address but also a MAC address or randomly generated identification information is used. In the prior art, in addition to the IP address normally described in the route control message such as the route search request message (Route Request: RREQ) or the route search request response message (Route Reply: RREP) of the routing protocol, the MAC address or random The generated identification information is added as a key. Thus, (set of destination IP address and destination key) and (set of source IP address and source key) are described in RREQ. The combination of the destination and the source (IP address + Key) is included in RREQ and RREP along with the route search, and is stored in the routing table entry of each node that has received these route control messages.

Each time a new routing control message is received, each node compares the (IP address + Key) pair included in the routing control message with the (IP address + Key) pair registered in each entry in the routing table. If the keys are different even though the IP addresses match, it is detected that a node having a duplicate address exists in the network. When a duplicate address is detected, all duplicate address entries are discarded, and each node having the duplicate address performs processing (renumbering) to obtain a new address. As a result, a packet whose destination is a duplicate address is not transferred, so that a packet transmitted to one node having a duplicate address is prevented from being erroneously transferred to the other node having a duplicate address.
NH Vaidya, "Weak duplicate address detection in mobile ad hoc networks", In the Proc. Of ACM MobiHoc 2002, June 2002, RR. 206-216.

  In the above prior art, all duplicate address entries are discarded from the routing table, so that packets sent to one node with duplicate addresses are erroneously transferred to the other node with duplicate addresses. While this is prevented, there is a technical problem that it is no longer transferred to one node that is a legitimate destination.

  The present invention provides a duplicate address detection method and apparatus in an ad hoc network that includes a plurality of wireless nodes, and in which a source node and a destination node exchange packets via at least one relay node, taking the following measures. There is a feature in the point.

  (1) In the duplicate address detection method of the present invention, the destination node analyzes a route request message received from the source node, determines a communication history with the source node based on the source address, and the destination A procedure in which a node detects the presence of a duplicate address when a destination sequence number is registered in the route request message even though there is no communication history with the source node; and A procedure for returning a route response message when the presence of an address cannot be detected; a procedure for a relay node to receive the route response message and register routing information including a destination address, a source address and a next hop in a routing table; The relay node determines the next hop of the packet transmitted from the source node to the destination node. Characterized in that it comprises a procedure for retrieving from the routing table based on the destination address and the sender address.

  (2) The duplicate address detection method of the present invention further provides that the source node assigns the destination sequence number to a destination whose destination sequence number is known, and assigns a predetermined identifier to a destination whose destination sequence number is unknown. And the destination node detects the presence of a duplicate address when the predetermined identifier is not given to the route request message even though there is no communication history with the source node. It is characterized by doing.

  (3) The duplicate address detection method of the present invention further includes a procedure in which the destination node that has detected the presence of the duplicate address transmits data for eliminating the duplicate address on the network.

  (4) The duplicate address detection apparatus of the present invention analyzes a route request message destined for its own node, and determines the presence or absence of a communication history with the source node based on the source address, the source Duplicate address detecting means for detecting the presence of a duplicate address when a destination sequence number is registered in the route request message even though there is no communication history with a node, and when the duplicate address cannot be detected And a means for returning a route response message.

  (5) The duplicate address detection device of the present invention is further configured such that the duplicate address detection means has an unknown destination sequence number in the route request message even though there is no communication history with the source node. It is characterized in that the presence of a duplicate address is detected when a predetermined identifier indicating is not given.

  (6) The duplicate address detection device of the present invention further includes a duplicate address elimination means for transmitting data for duplicate address elimination.

  (7) The duplicate address detection apparatus of the present invention further includes means for receiving a route response message and registering routing information including a destination address, a source address and a next hop in a routing table, and a next hop of a packet addressed to another node. Means for searching from the routing table based on the destination address and the source address, and means for transferring the packet addressed to the other node to the searched next hop.

  According to the present invention, if the destination node has no communication history in the routing table, and therefore the destination sequence number is registered in the route request message from the source node that communicates for the first time, the destination sequence number has the same address. Therefore, it is possible to detect that the address of the own node is assigned in the same network.

  Further, in the relay node, when registering the routing table information in the routing table based on the route response message, the destination address and the source address are registered in association with each other, and then the destination address is used when routing the packet. And the source address are extracted, and this is compared with the combination of the destination address and the source address associated with each other in each entry registered in the routing table. While the transmitted packet is prevented from being erroneously forwarded to the other node, it can be forwarded to one node that is a legitimate destination.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a functional block diagram showing a configuration of a main part of a network terminal (wireless node) according to the present invention. Here, illustration of configurations unnecessary for the description of the present invention is omitted.

  The network I / F 1 controls communication between the own node and the ad hoc network. The routing control unit 2 includes an RREQ analysis unit 201 that analyzes the received RREQ, an RREP analysis unit 202 that analyzes the received RREP, a routing table management unit 203 that updates the routing table 3 based on the received RREQ and RREP, and a routing table 3 includes a routing unit 204 that routes received packets based on the routing information registered in No. 3, a RREQ generation unit 205 that generates RREQ, an RREP generation unit 206 that generates RREP, and the like.

  When the duplicate address detection unit 4 receives an RREQ destined for its own node, the duplicate address detection unit 4 detects the presence of a duplicate address based on the presence / absence of a communication history with the transmission source node and the destination sequence number registered in the RREQ. To detect. When the duplicate address detection unit 4 detects the presence of a duplicate address, the duplicate address elimination unit 5 transmits data for eliminating the duplicate address to the target node.

  FIG. 2 is a diagram showing an example of the routing table 3. In this embodiment, for each IP address of the destination node, in addition to the IP address and sequence number of the next hop that have been registered in the past, transmission is performed. The IP address of the original node is newly registered.

  Next, a duplicate address detection procedure according to this embodiment will be described. Here, as shown in FIG. 3, the ad hoc network in which the node A and the node D relay and transmit the nodes B and C, and the ad hoc network in which the node E and the node G relay the node F and transmit Will be described from the state that is independently established. In this embodiment, the IP address of the node A is “1”, and similarly, the IP addresses of the nodes B, C, D, E, F, and G are “2”, “3”, and “4”, respectively. , “5”, “6”, “4”. Therefore, although the IP addresses of the node D and the node G are both “4”, since each ad hoc network is independent in the topology of FIG. 3, duplicate addresses do not occur.

  When transmitting from the node E to the node G for the first time, the node E is registered with a “U” (Unknown sequence number) flag indicating that the destination address is “4” of the node G and the destination sequence number is unknown. RREQ is generated by the RREQ generation unit 205 and broadcasted.

  In response to the reception of this RREQ, the node F starts the RREQ reception process of FIG. 5, and in step S10, the RREQ analysis unit 201 analyzes the RREQ to determine its destination node. Here, since the destination is a node other than the own node, the process proceeds to step S11. In step S11, as shown in FIG. 7A, in the routing table 3 of node F, the destination address is “5” of node E, the source address is “4” of node G, and the next hop is node E. Entry 1 that is “5” is registered. In step S12, the received RREQ is broadcast.

  Also in the destination node G, in response to the reception of this RREQ, the RREQ reception process of FIG. 5 is activated, and in step S10, the destination is determined to be the own node and the process proceeds to step S13. In step S13, the duplicate address detector 4 determines whether or not it is the first reception from the node E that is the transmission source. In the present embodiment, based on whether or not an entry related to the node E is registered in the routing table 3, it is determined whether or not it is the first reception. Here, since it is determined to be the first reception, the process proceeds to step S14. In step S14, the RREQ analysis unit 201 refers to the destination sequence number registered in the RREQ. Here, since the “U” flag is set instead of the destination sequence number, the process proceeds to step S15. In step S15, as shown in FIG. 8, in the routing table 3 of the node G, the destination address is “5” of the node E, the source address is “4” of the own node, and the next hop is “6” of the node F. Entry 1 is registered. In step S <b> 16, RREP having a destination address “5” of node E and a source sequence number Nseq-g is generated in RREP generation unit 206 and transferred to node F.

  In the node F, the RREP reception process of FIG. 6 is started in response to the reception of this RREP. In step S30, the RREP analysis unit 202 determines the destination. Here, since the destination is other than the own node, the process proceeds to step S31. In step S31, as shown in FIG. 7B, the destination address is “4” of the node G, the next hop is “4” of the node G, and the source address is “5” of the node E that is the current destination. Entry 2 is added to the routing table 3 of node F. In step S32, the RREP is transferred to the node E.

  Also in the node E, the RREP reception process of FIG. 6 is activated in response to the reception of this RREP, and the destination is determined in step S30. Here, since it is determined that it is addressed to the own node, the process proceeds to step S33, and the routing table management unit 203 updates the routing table 3 based on the received RREP. In step S34, the sequence number Nseq-g registered in RREP is registered in the routing table 3 as the destination sequence number of the node G.

  After that, when the nodes B and F move from the state of FIG. 3 and the two ad hoc networks are joined as shown in FIG. 4, the link connecting the node E and the node F is disconnected. When E tries to communicate with node G again, RREQ is broadcast again.

  In this RREQ, the sequence number Nseq-g of the node G notified by the RREP is registered as the destination sequence number, and other than that, it is forwarded to the node G via the nodes B and F in the same manner as described above. The node B having the same IP address is also transferred through the nodes B, F, and C.

  In response to the reception of this RREQ, the node G starts the RRPQ reception process of FIG. 5, and the destination is determined in step S10. Here, it is determined that the destination is the own node, the process proceeds to step S13, and it is determined whether or not the destination is the first reception from the node E. Here, since the entry related to the node E is already registered in the routing table 3, the process proceeds to step S15 and the routing table 3 is updated. In step S16, RREP is generated and transferred to node F in the same manner as described above.

  On the other hand, also in the node D, the RRPQ reception process of FIG. 5 is activated in response to the reception of this RREQ, and the destination is determined in step S10. Here, since the destination is the own node, the process proceeds to step S13, and it is determined whether or not the reception is the first from the node E. Since node D receives from node E for the first time, it proceeds to step S14. In step S14, the destination sequence number registered in RREQ is referred to. Originally, the destination sequence number Nseq-g is registered here even though the “U” flag should be set instead of the destination sequence number in the RREQ from the first communication partner. Therefore, the duplicate address detector 4 recognizes that there is another node with the same address, and proceeds to step S18. In step S18, the duplicate address resolution unit 5 executes a duplicate address process, which will be described later, and thereafter ends the process without returning RREP.

  Thereafter, the node F that has received the data packet having the destination address “4” from the node E that has received the RREP returned from the node G has received this data based on the entry 2 (FIG. 7) of its own routing table. Packets can be forwarded to node G.

  On the other hand, in the network topology of FIG. 4, RREQ is broadcast from the node A to the node D even when transmitting again from the node A to the node D. In this RREQ, the sequence number Nseq-d of the node D is registered as the destination sequence number. Otherwise, the node B, F, and C are relayed to the node D in the same manner as described above, and the IP address is set. The same G is also relayed through the nodes B and F.

  In node D, the RRPQ reception process of FIG. 5 is activated in response to the reception of this RREQ, and the destination is determined in step S10. Here, it is determined that the destination is the own node, the process proceeds to step S13, and it is determined whether or not this is the first reception from the node A. Here, since the entry related to the node A is already registered in the routing table 3, the process proceeds to step S15 and the routing table 3 is updated. In step S16, RREP is generated and transferred to node F in the same manner as described above.

  On the other hand, also in the node G, in response to the reception of this RREQ, the RRPQ reception process of FIG. 5 is activated, and the destination is determined in step S10. Here, since the destination is the own node, the process proceeds to step S13, and it is determined whether or not reception is from the node A for the first time. Since node D receives from node A for the first time, it proceeds to step S14. In step S14, the destination sequence number registered in RREQ is referred to. Originally, although the “U” flag should be set in the RREQ from the first communication partner, the destination sequence number Nseq-d is registered here. The unit 4 recognizes that there is another node with the same address, and proceeds to step S18. In step S18, the duplicate address resolution unit 5 executes a duplicate address process, which will be described later, and thereafter ends the process without returning RREP.

  The node F starts the RREP reception process of FIG. 6 in response to the reception of the RREP transferred from the node A, and the routing table has a destination address of the node D as shown in FIG. "4", the next hop is "3" of the node C, and the entry 4 whose source address is "1" of the node A is additionally registered.

  Thereafter, when the node F receives the data packet transmitted from the node E to the node G, the routing table in FIG. 7B is referred to based on the destination address “4” and the source address “5”, The routing unit 204 transfers the packet to the node G whose IP address is “4” based on the routing information of entry 2. When the node F receives the data packet transmitted from the node A to the node D, the node F refers to the routing table of FIG. 7D based on the destination address “4” and the source address “1”, and Based on the routing information of No. 4, the packet is transferred to the node C whose IP address is “3”.

  On the other hand, in the destination node G that has detected the duplicate address, the duplicate address elimination unit 5 determines a new address that does not duplicate in the network, as in the conventional technique. Then, a duplicate elimination message in which the new address is associated with the duplicate address is transmitted to the source node. The relay node that has received this message updates the routing information registered in the routing table 3 based on the received message. The source node that has received this message updates the routing table in the same manner as the relay node and rewrites the destination address in the IP header of the packet to be transmitted to the new address.

It is the functional block diagram which showed the structure of the principal part of the network terminal which concerns on this invention. It is the figure which showed an example of the routing table. It is the figure which showed an example before the change of a network topology. It is the figure which showed an example after the network topology change. It is a flowchart of a RREQ reception process. It is a flowchart of a RREP reception process. FIG. 6 is a diagram showing a routing table of node F. FIG. 6 is a diagram showing a routing table of node G.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Network I / F, 2 ... Routing control part, 3 ... Routing table, 4 ... Duplicate address detection part, 5 ... Duplicate address cancellation part

Claims (7)

In a duplicate address detection method in an ad hoc network, which includes a plurality of wireless nodes, and a source node and a destination node exchange packets via at least one relay node,
Analyzing the route request message received by the destination node from the source node and determining the communication history with the source node based on the source address;
A procedure for detecting the presence of a duplicate address when a destination sequence number is registered in the route request message even though the destination node has no communication history with the source node;
A procedure for returning a route response message when the destination node cannot detect the presence of the duplicate address;
A procedure in which a relay node receives the route response message and registers routing information including a destination address, a source address, and a next hop in a routing table;
An ad hoc network comprising: a step in which the relay node searches a next hop of a packet transmitted from the source node to a destination node from the routing table based on the destination address and the source address. Duplicate address detection method. The source node transmits a route request message to which a destination sequence number is given to a destination whose destination sequence number is known, and a destination identifier whose destination sequence number is unknown is assigned a predetermined identifier,
The destination node detects the presence of a duplicate address when the predetermined identifier is not given to the route request message even though there is no communication history with the source node. 2. A duplicate address detection method in an ad hoc network according to 1. 3. The duplicate address detection method in an ad hoc network according to claim 1, wherein the destination node that has detected the presence of the duplicate address includes a procedure of transmitting data for eliminating the duplicate address on the network. In the duplicate address detection device implemented in each wireless node constituting the ad hoc network,
Means for analyzing a route request message destined for the own node and determining the presence or absence of a communication history with the source node based on the source address;
A duplicate address detecting means for detecting the presence of a duplicate address when a destination sequence number is registered in the route request message even though there is no communication history with the source node;
Means for returning a route response message when the presence of the duplicate address cannot be detected, and a duplicate address detection apparatus in an ad hoc network. The duplicate address detecting means is duplicated when a predetermined identifier indicating that a destination sequence number is unknown is not given to the route request message even though there is no communication history with the source node. 5. The duplicate address detection apparatus in an ad hoc network according to claim 4, wherein presence of an address is detected. 6. The duplicate address detection apparatus in an ad hoc network according to claim 4, further comprising duplicate address elimination means for transmitting duplicate address elimination data. Means for receiving a route response message and registering routing information including a destination address, a source address and a next hop in a routing table;
Means for retrieving a next hop of a packet addressed to another node from the routing table based on a destination address and a source address;
7. The duplicate address detection apparatus in an ad hoc network according to claim 4, further comprising means for transferring a packet addressed to the other node to the searched next hop.

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