KR20040053850A - Method of cost-based route establishing for AODV routing protocol - Google Patents

Abstract

PURPOSE: A method for setting a route by weight in an AODV(Ad hoc On-demand Distance Vector) routing protocol is provided to reflect weight of each node in accordance with a network state, and to improve a process of transmitting or retransmitting an RREQ(Route Request) message, thereby efficiently setting a route in accordance with the reflected weight. CONSTITUTION: If an intermediate node receives an RREQ message(S401), the node decides whether the RREQ message is an overlapped message(S402). If so, the node compares a value of a weight cost with a weight value of a previously received RREQ message(S403). If weight of the currently received RREQ message is smaller, the node abandons the RREQ message(S404). If the received RREQ message is not overlapped, the node decides whether to know a route up to a destination node(S406). If so, the node unicasts the RREQ message by a reverse route(S407). If the node does not know the route, the node sets reverse route information(S409), records a previous weight value, and sets a new weight value to the RREQ message(S410), then broadcasts the RREQ message to an adjacent node(S411).

Description

Method of cost-based route establishment for AODV routing protocol

The present invention relates to a method for establishing a weighted path in an AODV routing protocol, and in particular, to each node by a weight in a path setting process of an AODV routing protocol used in a mobile ad-hoc network. The present invention relates to a path setting method based on a weight of an AODV routing protocol.

When the AODV routing protocol requires routing for data transmission, a Route Request (RREQ) message is generated and broadcasted to the neighbor node.

Then, when the intermediate node or the destination node having the route information to the destination node receives the corresponding route request message, it generates a route reply (hereinafter referred to as RREP) message and transmits the corresponding route request message. Unicast transmission to the node.

In addition, if the intermediate node does not have destination information, the corresponding RREQ message is broadcasted to the neighboring node again.

1 is a block diagram showing the format of a routing request message of a conventional AODV routing protocol.

Referring to FIG. 1, the RREQ message of the conventional AODV routing protocol counts a type field, J, R, G, D, and U field information and reserved fields, and the number of hops to which the corresponding RREQ message is transmitted. There is a field (Hop Count) to store.

And an ID (RREQ ID) for identifying the RREQ request message, an IP address of the destination node, a sequence number of the destination node, and an IP address and sequence number of the source node that transmitted the routing request message.

Setting the path by the above RREQ message is as follows.

2 is a flow chart of a path establishment of a conventional AODV routing protocol.

Referring to FIG. 2, in an ad hoc network shown only from node 1 101 to node 5 105, in order to transmit data to node 5 105, node 1 101 has an RREQ having the format of FIG. 1. The message is sent to neighboring node 2 (102) and node 3 (103).

Then, if node 2 102 does not know the destination route to node 5 105 as an intermediate node, node 2 102 forwards the corresponding RREQ message to neighbor node 3 103 and node 4 104.

The node 3 103 transmits the RREQ message received from the node 1 101 to the neighbor node 2 102.

As above, if it does not know the path to node 5 105, which is the destination node, each node forwards the RREQ message to neighboring nodes.

Also, if the same RREQ message is received, such as node 2 102 or node 3 103, only the first received one is used.

When the node 5 (105) receives the RREQ message from the node 1 (101), since it is the destination node, the node 5 (105) unicasts the RREP message in the reverse direction of the path to which the corresponding RREQ message is transmitted.

That is, as shown in FIG. 2, node 5 105 is from node 1 101 to node 2 102, and from node 2 102 to node 4 104, and at node 4 104. This is to send the RREP message in the reverse direction of the RREQ message sent to it (node 5-node 4-node 2-node 1).

The above-described process of path setting will be described according to the operation order as follows.

3 is a flowchart illustrating a path setting method of a conventional AODV routing protocol.

Referring to FIG. 3, when each node receives an RREQ message (S301), it is determined whether the corresponding RREQ message is duplicated (S302), and if it is duplicated, discards the corresponding RREQ message. It is determined whether the path information to the destination node of the RREQ message is known or is the corresponding destination node (S304).

If it is determined in step S304 that the route information to the destination node is unknown, reverse route information is set and stored (S307), and broadcasted to a neighboring node (S308). In this case, the setting of the reverse path information in the RREQ message is to know to which node to deliver the RREP message, which is a response to the RREQ message.

As a result of the determination in step S304, if the route information to the destination node is known, the RREP message is transmitted unicast to the node that sent the RREQ message, that is, in the reverse direction (S305), and enters the standby state (S306).

However, in the conventional method as described above, since the path is set by the path through which the initial RREQ message is transmitted, it is impossible to reflect the state of the path, which can be expressed as a weight, and thus radio resources are inefficiently used. As a result, routing problems may arise due to inefficiency.

In order to solve the above problem, the present invention provides a process for transmitting or re-delivering the RREQ message by reflecting the weight of each node according to the network state in the path setting method for data transmission between each node in the ad hoc network. It is an object of the present invention to provide a routing method based on the weight of the AODV routing protocol, which enables an efficient routing according to the weight.

1 is a block diagram showing the format of a routing request message of a conventional AODV routing protocol.

2 is a flow chart of a path establishment of a conventional AODV routing protocol.

3 is a flowchart illustrating a path setting method of a conventional AODV routing protocol.

4 is a block diagram illustrating a message format for path setting by weight of an AODV routing protocol according to an embodiment of the present invention.

5 is a flowchart illustrating a path setting method based on a weight of an AODV routing protocol according to an exemplary embodiment of the present invention.

6 is a flowchart illustrating a method for establishing a path based on a weight of an AODV routing protocol according to an embodiment of the present invention.

<Brief description of the main parts of the drawings>

101 ~ 105: node

Path setting method by the weight of the AODV routing protocol according to the present invention,

A method for establishing a node-to-node route using an ad hoc on-demand distance vector (AODV) routing protocol between nodes of an ad-hoc network composed of a plurality of wireless communication nodes, the method comprising: (a) a destination for data transmission from any source node; Creating a route setting request message for inquiring route information to the node, and broadcasting the route setting request message to a neighboring node, such that the route setting request message is transmitted to the destination node; (b) determining, by any node that receives the routing request message, whether the routing request message is a duplicate message; (c) if the routing request message is a duplicated message, comparing the weight value included in the routing request message with a weight of the routing request message previously received; And (c) resetting the reverse path information to the corresponding path and discarding the path setting request message if the weight result is larger than the previously received path setting request message.

Preferably, the path setting request message includes a 'C' flag for requesting path setting according to the weight of each inter-path path in the corresponding path setting, and a weight value of each inter-path path according to the 'C' flag. Characterized in that it comprises a.

Preferably, in the step (a), if the source node transmits a route request message to a neighboring node, if the node neighboring the source node is not the destination node of the route request message received, the corresponding route is set. It is characterized in that the request message is transmitted to the neighbor node and its own so that it is transmitted to the destination node.

Preferably, when the determination result of step (b) indicates that the corresponding route setting request message is not a duplicated message, any node that has received the routing request message is the destination node of the routing request message, or If the route information to the node is known, unicasting a routing response message to the source node by reverse route information.

Preferably, as a result of the determination in step (b), if the corresponding route setting request message is not a duplicately received message, if the corresponding node is not the destination node and does not know the route information to the destination node, the reverse path information is set. And resetting the weight value of the corresponding route request message to broadcast to neighboring nodes.

Preferably, the resetting of the weight value comprises storing a weight value of a path from which the path setting request message has been received at the corresponding node, and resetting a weight value of a path to transmit the path setting request message. .

Preferably, as a result of the comparison in the step (c), if it is determined whether the path setting request message is duplicated by the arbitrary node, and if the corresponding path setting request message is duplicated, the weight value of the corresponding path setting request message is transferred. If the weight is not greater than the weight of the routing request message received, the discarding of the routing request message.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

4 is a block diagram illustrating a message format for path setting by weight of an AODV routing protocol according to an embodiment of the present invention.

Referring to FIG. 4, in order to set a path by weight according to the present invention, a message format reflecting a weight on each node is required.

Accordingly, a 'C' flag for indicating that a path setting by weight is applied to a reserved field which is not used in the conventional message format, and a weight field Cost for transmitting a weight value of each node are reserved. Construct RREQ messages by adding them using fields.

As described above, the path setting by the RREQ message including the 'C' flag that adds the weight value to the message and uses the path setting method according to the weight may be performed as follows.

5 is a flowchart illustrating a path setting method based on a weight of an AODV routing protocol according to an exemplary embodiment of the present invention.

Referring to FIG. 5, an RREQ for requesting the node 1 101 to establish a path to the node 5 105 between nodes 1 101 to 5 5 105 having the same configuration as in FIG. 2 described above. When broadcasting the message, the RREQ message is sent to node 2 102 and node 3 103.

In this case, when the node 2 102 determines that the path weight from the node 3 103 is higher than the path weight from the node 1 101, the node 2 101 receives the RREQ message received from the node 1 101. If the weight value of the duplicated RREQ message received later from node 3 (103) is better, even if it has already transmitted to node 4 (103), the reverse information stored and set to node 1 (101) that arrived first is stored in node 3 (103). ) To send a RREP message for the RREQ message to node 3 (103) instead of node 1 (101) upon receipt.

This is not due to the received turn of the RREQ message, but by way of path weighting.

Therefore, when the RREQ message is received at the node 5 105, the reverse path is in turn in the order of 'node 5-node 4-node 2-node 3-node 1', thereby establishing a path different from the conventional path.

Since the weight of the path is that each node is changed according to the state of the path, in the case of FIG. 5, node 3 (node 3) node 3 (rather than transmitting data directly from node 2 102 to node 1 101). When data transmission to the node 1 (101) has a fast network state via the 103, it is possible to set the efficient path.

The path setting by the weight will be described in more detail as follows.

6 is a flowchart illustrating a method for establishing a path based on a weight of an AODV routing protocol according to an embodiment of the present invention.

Referring to FIG. 6, when an intermediate node receives an RREQ message (S401), it is first determined whether the corresponding RREQ message is a duplicately received message (S402). In this case, determining whether or not the duplicated RREQ message can be determined by the source node IP address and the RREQ ID value in the format of FIG. 4.

At this time, if the corresponding RREQ message is duplicated, the value of the weight field Cost is compared with the weight value of the previously received RREQ message (S403). If less than the weight value of the RREQ message is discarded (S404).

However, if the weight of the currently received RREQ message is greater than the previously received RREQ message, the node changes the reverse path information and discards the RREQ message.

That is, in FIG. 5, the node 2 102 first sets the reverse path information to the node 1 101 based on the RREQ message received from the node 1 101, and then the node 3 103 having a larger weight. When the same RREQ message is received from the node, the reverse path information to the node 1 101 that has been set is changed to the node 3 103.

If the RREQ message received in step S402 is not a duplicate message, it is determined whether the path to the destination node is known (S406). If the path to the destination node is known, the RREQ message is unicasted by the reverse path (S407). ).

However, if one does not know the route information to the destination node, after setting up the reverse route information (S409), the previous weight value is recorded, and a new weight value is set in the corresponding RREQ message (S410), and the RREQ is neighbored to the node. The message is broadcasted (S411).

Referring to step S410 described above in more detail, by referring to FIG. 5, node 2 102 records a previous weight value, that is, a path weight from node 3 103 to itself, and a next weight value, that is, node 4 104. The path weight up to) is reset in the weight field of the RREQ message and then the corresponding RREQ message is transmitted to the node 4 104.

The nodes that have performed all the operations are in the standby state (S408).

At this time, all of the RREQ message and the RREP message is set by the same classification by the RREQ ID.

As described above, the path setting method based on the weight of the AODV routing protocol according to the present invention uses weights reflected according to the state of each path as compared with the conventional method of setting the path in the order of receiving the RREQ message. Therefore, it is possible to set only the paths with good path status so that data can be transmitted through the efficient path in data transmission, and the effective path setting is reflected by the weight of various nodes and paths such as the weight of each node's power usage. This has a possible effect.

Claims (8)

In a node-to-node routing method using an ad hoc on-demand distance vector (AODV) routing protocol between nodes of an ad-hoc network composed of a plurality of wireless communication nodes, (a) To transmit data from any source node, a route establishment request message is prepared and broadcasted to a neighboring node to inquire route information to the destination node, and the route establishment request message is transmitted to the destination node. To lose; (b) determining, by any node that receives the routing request message, whether the routing request message is a duplicate message; (c) if the path setting request message is a duplicated message, comparing the weight value reflecting the path state included in the path setting request message with the weight of the path setting request message previously received; And (d) resetting the reverse path information to the corresponding path if the weight of the currently received path setting request message is greater than that of the previously received path setting request message. Path setting method by the weight of the AODV routing protocol comprising a. The method of claim 1, The path setting request message includes a 'C' flag requesting path setting according to the weight of each inter-path path in the corresponding path setting, and a weight value of each inter-path path according to the 'C' flag. Path setting method by the weight of the AODV routing protocol, characterized in that the. The method of claim 1, In the step (a), if the source node transmits a route request message to the neighboring node, if the destination node of the route request message received by the node neighboring the source node is not itself, the corresponding route request message is sent. A method for routing by weight of an AODV routing protocol, characterized in that the broadcast is transmitted to a node adjacent to itself and transmitted to a destination node. The method of claim 1, As a result of the determination of step (b), if the corresponding route request message is not a duplicated message, any node that has received the route request message is the destination node of the route request message or is sent to the destination node. If the routing information is known, unicasting a routing response message to the source node by reverse routing information. The method of claim 1, As a result of the determination in step (b), if the corresponding route setting request message is not a duplicated message, if the corresponding node is not the destination node and does not know the route information to the destination node, the reverse route information is set and the corresponding route is set. And resetting the weight value of the setup request message to broadcast to neighboring nodes. The method of claim 5, The resetting of the weighting value may include: storing the weighting value of the path from which the routing request message has been received at the corresponding node, and resetting the weighting value of the path for transmitting the routing request message. Path setting method by weight of. The method of claim 1, A comparison result of step (c), As a result of determining whether the routing request message is duplicated by the arbitrary node, when the corresponding routing request message is duplicated, the weight value of the routing request message is not greater than the weight of the routing request message previously received. If necessary, discarding the corresponding route request message. The method of claim 1, The weighting value is determined and changed according to the power usage of each node. Path setting method according to the weight of the AODV routing protocol.