KR100462028B1 - Method of internet gateway discovery in Ad-hoc network - Google Patents

Abstract

The Internet gateway (IG) discovery method of the Ad-hoc network according to the present invention includes an Internet providing a wired Internet service, a plurality of nodes performing data transmission and reception by a wireless multi-hop method, and the Internet. Internet gateway discovery method of the Ad-hoc network consisting of a wired interface for connection and an Internet gateway having a wireless interface for connection with the plurality of nodes at the same time, (a) the Internet gateway is a hop hop agent agent message from itself Transmitting broadcast to only the first group within the first group, wherein the first group is a group of nodes; (b) receiving, by the node of the first group, an agent advertisement message from the broadcasted Internet gateway, and updating corresponding Internet gateway information; (c) a second group away from the Internet gateway a predetermined hop or more, where the second group is a group of nodes, to all nodes an agent request message requesting the Internet gateway information for Internet access at any node. Transmitting a broadcast; And (d) an agent advertisement including the Internet gateway information that the node of the first group receiving the broadcast agent request message has as the node of the second group broadcast the agent request message. Composing the message and sending it unicast.

According to the present invention, it is expected that the wireless nodes in the Ad-hoc network can minimize the network load generated during the IG discovery to access the Internet and maintain the latest path information.

Description

Method of internet gateway discovery in Ad-hoc network

The present invention relates to a method for searching for an Internet gateway (hereinafter referred to as an IG) in an Ad-hoc network. In particular, each Ad-hoc node in the structure connected to the Internet confirms the existence of the IG, The present invention relates to an IG discovery method of an Ad-hoc network for efficiently searching for an IG for routing.

Ad-hoc networks are ad-hoc networks configured autonomously between nodes without the aid of a base network device such as a base station. Ad-hoc nodes communicate with each other using a radio interface, which causes limitations in transmission distance. Therefore, multi-hop communication is performed through intermediate nodes for communication between remote Ad-hoc nodes. Therefore, Ad-hoc nodes include routing functions in addition to basic host functions.

Ad-hoc network can exist completely independent from other existing networks or interwork with existing wired network, and Ad-hoc node plays the role of gateway to wired internet to access wired internet. IG must be present in the Ad-hoc network.

The IG is a node belonging to both the Ad-hoc network and the wired Internet. The IG performs a function of routing packets between the Ad-hoc node and the Internet node. You need to retrieve the route information.

1 is a block diagram showing the structure of an Ad-hoc network.

Referring to FIG. 1, the Ad-hoc network 200 interworking with the wired Internet is connected to the Internet network 100 through the IG 210 and connects a plurality of Ad-hoc nodes 220-1 to 220 -N. Include.

Direct communication between nodes located within the radio access area such as Node A 220-1 and Node B 220-2 is possible, and wireless communication between Node A 220-1 and Node C 220-3 is possible. Nodes located outside the transmission area communicate with each other by the routing function of an intermediate node located between two nodes, such as Node B 220-2.

The IG 210 is configured for the Ad-hoc node to access the wired Internet 100, and the IG 210 is wired for communication with the wired Internet 100 in addition to a wireless interface for communication with the Ad-hoc node. With the interface, it serves as a gateway between the Ad-hoc network 200 and the wired Internet (100).

Searching for and registering the IG 210 in the Ad-hoc nodes 220-1 to 220-N (represented by 220) in the Ad-hoc network interworking with the wired Internet configured as described above is as follows.

2 is a flowchart of a method for searching for an internet gateway in a conventional Ad-hoc network.

Referring to FIG. 2, in order to access the wired Internet through the IG 210, the Ad-hoc node 220 needs to know the address of the IG 210 and the route information to the IG 210.

Therefore, the IG 210 is searched, and the IG 210 periodically sends an Ad-hoc network AA to the Ad-hoc node 220 to inform the Ad-hoc node 220 of the Ad-hoc network 200. The ad-hoc node 220 receiving the message and registering the message is registered with the IG 210 through a registration procedure.

In addition, as shown in FIG. 2, when the Ad-hoc node 220 attempting to access the Internet does not receive an agent advertisement message within a time limit, an Agent Solicitation (AS) is broadcasted to the entire network ( S201) IG 210 and the IG 210 receives the agent request message, and delivers the agent advertisement message to the Ad-hoc node 220 that generated the agent request message in unicast (S202).

Then, the Ad-hoc node 220 attempting to access the Internet performs the registration procedure using the address and route information of the IG 210 using the agent advertisement message from the IG 210 (S203).

However, since the method broadcasts the agent advertisement message and the agent request message to the entire Ad-hoc network 200, the topology of the Ad-hoc network 200 changes dynamically, and the Ad-hoc network having a low transmission bandwidth ( 200) there is a problem that acts too much burden.

In order to solve the above problem, when the transmission period of the agent advertisement message is increased, the frequency of occurrence of the agent request message is increased, and it is difficult to maintain the latest information to the IG 210.

Therefore, there is a problem that may affect stable data communication between the Ad-hoc nodes 220 and between the Ad-hoc node 220 and the Internet 100.

In order to solve the above problem, the present invention limits the transmission range of the agent advertisement message periodically broadcast in the IG within a certain range so that the Ad-hoc node located within a certain range continues to maintain the route information to the latest IG, The IG discovery method of the Ad-hoc network which minimizes the network load incurred during IG discovery and maintains up-to-date route information by transmitting agent advertisement messages on behalf of the IG to Ad-hoc nodes located outside a certain range. The purpose is to provide.

1 is a block diagram showing the structure of an Ad-hoc network.

2 is a flowchart of a method for searching for an internet gateway in a conventional Ad-hoc network.

3 is a flowchart illustrating a method for discovering an internet gateway of an Ad-hoc network according to an embodiment of the present invention.

4 is a flowchart illustrating a message flow and route information setting between nodes in an internet gateway discovery method of an ad-hoc network according to an exemplary embodiment of the present invention.

<Brief description of the main parts of the drawings>

100: Internet network 200: Ad-hoc network

210: IG 220, 220-1 ~ 220-N: Ad-hoc node

IG discovery method of the Ad-hoc network according to the present invention,

An Internet having a wired Internet service, a plurality of nodes performing data transmission and reception by a wireless multi-hop method, a wired interface for connecting to the Internet, and a wireless interface for connecting to the plurality of nodes at the same time. The method of discovering an internet gateway of an Ad-hoc network configured with a gateway includes: (a) allowing the Internet gateway to transmit an agent advertisement message only to a first group within a certain hop from the first group, where the first group is a group of nodes; Transmitting a broadcast; (b) receiving, by the node of the first group, an agent advertisement message from the broadcasted Internet gateway, and updating corresponding Internet gateway information; (c) broadcasts an agent request message requesting the Internet gateway information for Internet access from any node belonging to a second group more than a predetermined hop away from the Internet gateway, where the second group is a group of nodes; Doing; And (d) an agent advertisement including the Internet gateway information that the node of the first group receiving the broadcast agent request message has as the node of the second group broadcast the agent request message. Composing the message and sending it unicast.

Preferably, the agent advertisement message of step (a) is characterized by including the address information of the Internet gateway.

Preferably, in the step (a), the Internet gateway transmits an agent advertisement message with a time to live (TTL) of a predetermined number of hops in order to propose that the agent advertisement message be transmitted only to nodes of the first group. Characterized in that.

Preferably, in step (a), I) the Internet gateway broadcasting an agent advertisement message to a node one hop away; II) A node at a distance of one hop from the Internet gateway receiving the agent advertisement message updates address information of the Internet gateway and route information to the Internet gateway included in the agent advertisement message, and sets a transmission validity count. '1 decrease, and then transmit to another node at one hop distance from itself; And III) repeating step II, the agent advertisement message is received at a node located at a predetermined hop distance from the Internet gateway, updating the address of the Internet gateway and route information to the Internet gateway, and then advertising the agent. Stopping the transmission of the message.

Preferably, in step (d), the method comprises: receiving an agent request message transmitted by a node of the first group by a node of the second group; Identifying, by a node of the first group, a second group node that has transmitted the received agent request message, and identifying a delivery path; And configuring the agent advertisement message using the Internet gateway information owned by the node of the first group, and transmitting the agent advertisement message to the node of the second group that has transmitted the agent request message through the confirmed delivery path. Transmitting the cast.

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

3 is a flowchart illustrating a method for discovering an internet gateway of an Ad-hoc network according to an embodiment of the present invention.

Referring to FIG. 3, an Ad-hoc node k (220-k) located within the range of IG 210 and any k hops and k-hops not located in the range of IG 210 and k hops or more. Message transmission and reception between Ad-hoc nodes 220-n in range will be made.

First, the procedure of acquiring and registering the address and route information of the IG 210 at the Ad-hoc node k 220-k located within the range of k-hops is performed by the IG 210 at a predetermined period. It transmits to all Ad-hoc nodes located in the range up to hop (S301).

At this time, in order to transmit the agent advertisement message only to the Ad-hoc node within the k-hop range, the IG 210 sets the agent advertisement message TTL (Time To Live) value to k, and the Ad-hoc located within the k-hop. Nodes receive the Agent Advertisement message from the IG 210 to decrease the TTL by 1 and then deliver it to the next node so that it is delivered only to Ad-hoc nodes within the k-hop range.

Then, the Ad-hoc node k (220-k) located within the range of k-hop registers with the IG 210 using the address and route information of the IG 210 included in the received agent advertisement message (S302). .

If the Ad-hoc node n (220-n) located in the range of k-hop or more needs to access the Internet, an agent request message is generated and broadcasted to the Ad-hoc network 200 (S303). .

When the Ad-hoc node k (220-k) within k-hops receives the agent request message, the Ad-hoc node k (220-k) receives the agent advertisement message received from the IG 210 which it has. The unicast is transmitted to the hoc node n (220-n) (S304).

Then, the Ad-hoc node n 220-n may register with the IG 210 (S305).

The IG discovery method of the ad-hoc network operating as described above will be described in more detail according to the message flow and path information setting flow between nodes.

4 is a flowchart illustrating a message flow and route information setting between nodes in an internet gateway discovery method of an ad-hoc network according to an exemplary embodiment of the present invention.

First, ad-hoc nodes A (220-1), node B (220-2), node C (220-3), located within k-hops of IG 210 and at distances greater than k-hops from IG 210. A configuration including a node D 220-4, a node E 22-5, and a node F 220-6 will be described.

Referring to FIG. 4, (a) referring to the flow of messages, the IG 210 periodically transmits AA (Agent Advertisement Message), in which case, the TTL is set to k and transmitted (①).

When Node A 220-1, which is one hop away from IG 210, receives the AA sent by IG 210, it generates route information to IG 210 and reduces the TTL by '1', and then reconnects to next Node B 220. -2) (②).

When AA moves k-hop through the above procedure, node C 220-3, which is k-hop away from IG 210, has a TTL value of '0', and thus no longer forwards AA to neighboring nodes. I never do that.

Ad-hoc nodes located within k-hops from the IG 210 such as the Node A 220-1, the Node B 220-2, and the Node C 220-3 are AA transmitted by the IG 210. If necessary, the registration process is performed in the IG 210 when necessary, and the latest IG 210 information is maintained according to AA which is periodically transmitted.

Nodes away from the IG 210 by k-hops or more perform the search procedure to the IG 210 only when the Internet 100 needs to be connected.

As shown in FIG. 4, when Node F 220-6, which is more than k-hops away from IG 210, needs an Internet connection, Node F 220-6 sends an Agent Request Message (AS) around it. Broadcast to nodes (iii).

Then, neighboring node E 220-5 of node F 220-6 receives the corresponding AS and generates path information to node F 220-6 that has transmitted the AS message. 4), the node D 220-4 generates the path information to the node F 220-6, and transmits the AS back to the node C 220-3 (i).

When the node C 220-3 receives the AS transmitted from the node F 220-6, the node C 220-3 generates route information to the node F 220-6 which transmitted the AS. Then, after generating the AA by using the IG (210) information it owns, and transmits the AA to the node D (220-4) (⑬).

At this time, the node D 220-4 generates route information to the IG 210, transmits the received AA to the node E 220-5 in unicast, and receives the AA. 5) generates the path information to the IG 210 and transmits the received AA to the node F (220-6) in unicast, if the node F (220-6) receives the AA (⑭) IG After the route information to 210 is generated, it is registered in the IG 210.

In addition, referring to (b) the path information setting process in FIG. 4, the node A 220-1 is an Ad-hoc node that is one hop away from the IG 210. Has route information (1).

Similarly, node C 220-3 away from k-hops also has path information from node B 220-2 to IG 210 based on the path on which AA was transmitted.

And, in the case of node F 220-6 that is more than k-hop apart, route information (가는) to the IG 210 based on a route through which AA is transmitted from node C 220-3 that is k-hop apart. Will have

As described above, the IG discovery apparatus and method of the Ad-hoc network according to the present invention are efficiently performed based on the number of hops when the Ad-hoc network searches for the IG in a network structure interworking with the wired Internet through the IG. In this way, an agent advertisement message broadcasted by the IG to inform its own information is periodically received by only nodes within a certain hop number to have the IG information, and nodes located above the arbitrary hop number are only required when an internet connection is required. By sending an Agent Request message and allowing a node within any hops to receive it to send an Agent Advertisement message unicast to that node, reducing the load on the network and providing up-to-date information and route information for the IG. It is effective to know effectively.

Claims (5)

An Internet having a wired Internet service, a plurality of nodes performing data transmission and reception by a wireless multi-hop method, a wired interface for connecting to the Internet, and a wireless interface for connecting to the plurality of nodes at the same time. In the method of discovering the Internet gateway of the Ad-hoc network consisting of the gateway, (a) the Internet gateway sending a broadcast message so that an agent advertisement message is sent only to a first group within a certain hop from itself, where the first group is a group of nodes; (b) receiving, by the node of the first group, an agent advertisement message from the broadcasted Internet gateway, and updating corresponding Internet gateway information; (c) a second group away from the Internet gateway a predetermined hop or more, where the second group is a group of nodes, to all nodes an agent request message requesting the Internet gateway information for Internet access at any node. Transmitting a broadcast; And (d) an agent advertisement message including the Internet gateway information owned by the node of the first group that has received the broadcasted agent request message to the node of the second group that has broadcast the agent request message; To create a unicast transmission Internet gateway discovery method of the ad-hoc network comprising a. The method of claim 1, Agent advertisement message of step (a) comprises the Internet gateway search method of the Ad-hoc network, characterized in that including the address information. The method of claim 1, In step (a), the Internet gateway transmits an agent effective message (TTL; Time To Live) of a predetermined number of hops in order to propose that the agent advertisement message is transmitted only to the nodes of the first group. Internet gateway discovery method of Ad-hoc network. The method of claim 1, In the step (a), i) the internet gateway broadcasting an agent advertisement message to a node one hop away; ii) a node at a distance of one hop from the Internet gateway receiving the agent advertisement message updates address information of the Internet gateway and route information to the Internet gateway included in the agent advertisement message, and sets a transmission validity count. '1 decrease, and then transmit to another node at one hop distance from itself; And iii) repeating step ii), an agent advertisement message is received at a node located at a predetermined hop distance from the internet gateway, and the agent advertisement message is updated after updating the address of the internet gateway and route information to the internet gateway. Steps to Stop Sending Messages Internet gateway discovery method of the ad-hoc network comprising a. The method of claim 1, In step (d), receiving, by the node of the first group, the agent request message broadcasted by the node of the second group; Identifying, by a node of the first group, a second group node that has transmitted the received agent request message, and confirming a delivery path; And The node of the first group constructs an agent advertisement message using the Internet gateway information owned by the node of the first group, and unicasts the agent advertisement message to the node of the second group that has transmitted the agent request message through the confirmed delivery path. Sending steps Internet gateway discovery method of the ad-hoc network comprising a.