KR101845671B1 - Resource discovery method and system for sensor node in the constrained network - Google Patents

Abstract

The present invention relates to a method and system for identifying resources of a sensor node in a limited network. More particularly, the method comprises the following steps of: allowing at least one sensor node belonging to a network for which a routing path is set to transmit a control message including resource information to a proxy through an edge router; allowing the proxy to identify the resource information included in the control message and generate and manage a resource table including the identified resource information; allowing a cloud server to request, to the proxy, transmission of the resource table for the sensor node on the network; and allowing the proxy to transmit the resource table to the cloud server in response to the request of the cloud server. As such, a method and system for identifying resources of a sensor node in a limited network can enable the cloud server to easily identify the resources of a plurality of sensor nodes without a direct communication with the sensor nodes by allowing the proxy to previously receive the resource information from the sensor nodes constituting the limited network before the request of the cloud server and to build a resource table, and allowing the proxy to transmit, to the cloud server, the resource table previously generated by the proxy when the cloud server requests the resource table for the sensor nodes.

Description

METHOD AND SYSTEM FOR RESONANCE DISCOVERY METHOD AND SYSTEM FOR RESPONSIVE NETWORK OF SENSOR NODE

The present invention relates to a method and system for discovering resources of a sensor node in a limited network, and more particularly, to a method and system for discovering resources of a sensor node efficiently while reducing power consumption of the sensor node in a limited network implementing an object Internet service environment And more particularly, to a method and system for discovering resources of a sensor node in a limited network.

In recent years, the Internet of Things (IoT), which has received much attention from people, refers to a technique of sharing information as objects are connected to the Internet to perform communication between objects. In particular, due to the rapid development of wireless communication technology, the Internet of things is gradually increasing in the range of communication between people, people, objects, things and objects, and furthermore, M2M (Machine to Machine ).

In the past, the short distance communication technology exchanged a relatively small amount of data at a short distance of about 10 to 30 m. In recent years, as the communication distance has expanded to about 100 m, the amount of data transmission has also been explosively increased, It is also possible. In addition, the wireless network can be speeded up for high capacity multimedia communication, and the network coverage can be expanded, so that a large capacity service can be stably provided.

Due to the proliferation of such Internet services, the number of terminals connected to the Internet rapidly increases and they are formed as networks. Among these networks, a sensor network is a network composed of a plurality of sensor nodes operating with a low computing power and a low-capacity battery power. At this time, the used sensor node senses an event occurring at a location where the sensor node is disposed, processes the detected event, and performs a communication function.

The sensor node used in this sensor network is very limited in resources such as power, memory and computation processing part than existing nodes such as PC, smart phone and tablet PC, is very sensitive to power consumption, There is a problem that a security problem occurs in a sensor network or power consumption is rapidly increased due to data transmission / reception due to frequent movement.

Korean Registered Patent No. 10-1611988 (Apr. Korean Patent Registration No. 10-1679706 (Nov. 21, 2016)

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above problems occurring in the prior art, and it is an object of the present invention to provide a method and apparatus for detecting a resource of a sensor node, And a system and method for discovering resources of a sensor node.

In a method of discovering a resource of a sensor node in a limited network according to an embodiment of the present invention, at least one sensor node constituting a network transmits a first control message including network information to an edge router, Generating at least one second control message including resource information by the at least one sensor node and transmitting the second control message to the proxy through the edge router, the proxy verifying the resource information included in the second control message Generating and managing a resource table including the identified resource information; requesting a proxy server to transmit a resource table for the sensor node of the network by the cloud server; and, in response to the request of the cloud server, Wherein the resource table is stored in the cloud server And transmitting a.

In the second control message, the resource information may be included in an option field of the message structure.

Wherein each of the at least one sensor node generates a second control message including resource information and transmits the second control message to the proxy through the edge router, wherein the at least one sensor node transmits caching information and / And may further include observation information.

When the new sensor node in the network is searched, the resource table may be updated with the resource information about the searched new sensor node.

The resource discovery system of the sensor node in the limited network according to another embodiment of the present invention transmits a first control message including network information to an edge router to set a routing path in the network, At least one sensor node for transmitting the generated control message to the proxy through the edge router, a resource table included in the second control message received from the at least one sensor node and generating a resource table including the checked resource information A proxy for transmitting the resource table to the cloud server when requesting transmission of a cloud server and a cloud server for requesting transmission of a resource table for the sensor node of the network to the proxy and receiving the requested resource table, .

As described above, according to the method and system for discovering resources of a sensor node in a limited network according to the present invention, resource information of a plurality of sensor nodes constituting a limited network is tabled before a request of a cloud server, The proxy server can transmit the table generated by the proxy to the cloud server so that the cloud server can easily discover the resource of the sensor node without direct communication with the sensor node.

In addition, according to the method and system for discovering resources of a sensor node within a limited network according to the present invention, a cloud server requests transmission of a resource table to a proxy, so that the cloud server performs direct data transmission / reception with each sensor node constituting the restricted network The power consumption of data transmission / reception between the cloud server and the sensor node can be greatly reduced.

1 is a schematic diagram of a resource discovery system for a sensor node within a restricted network according to an embodiment of the present invention.
2 is a flowchart of a resource discovery method of a sensor node in a restricted network according to another embodiment of the present invention.
3 is a diagram illustrating a structure of a control message transmitted together with an IP header.
4 is a flowchart of a resource discovery method of a newly participating new sensor node in the network.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art, however, that these examples are provided to further illustrate the present invention, and the scope of the present invention is not limited thereto.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, in which: It is to be noted that components are denoted by the same reference numerals even though they are shown in different drawings, and components of different drawings can be cited when necessary in describing the drawings. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the following detailed description of the principles of operation of the preferred embodiments of the present invention, it is to be understood that the present invention is not limited to the details of the known functions and configurations, and other matters may be unnecessarily obscured, A detailed description thereof will be omitted.

In addition, in the entire specification, when a part is referred to as being 'connected' to another part, it may be referred to as 'indirectly connected' not only with 'directly connected' . Also, to include an element does not exclude other elements unless specifically stated otherwise, but may also include other elements.

Also, the terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms may be used for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises", "having", and the like are intended to specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, , Steps, operations, components, parts, or combinations thereof, as a matter of principle.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be construed as meaning consistent with meaning in the context of the relevant art and are not to be construed as ideal or overly formal in meaning unless expressly defined in the present application .

The number of terminals connected to the Internet has also been explosively increasing due to the rapid development of the Internet environment of objects. In order to construct the Internet environment of objects, the use of IPv6 to generate terminal identification information that is close to unlimited while utilizing the current network communication structure Is essential.

Accordingly, the constrained network to which the present invention is applied is a low-power wireless network (Low-power and Lossy Networks), which provides IP to the sensor nodes constituting the network to ensure seamless connectivity with the existing Internet network And IPv6 Low Power Wireless Personal Area Network (6LoWPAN) may be used.

This 6LoWPAN is an IEEE 802.15.4-based wireless network, and is an IP-based sensor network standard using IPv6 technology. Designed for low power, IEEE 802.15.4 has a maximum transmission limit of 127 bytes.

In particular, 6Lowpan uses an edge router (LBR: Load Balancing Router) as a gateway for communication with an external network to transmit sensing information sensed by a sensor node to an external monitoring device. At this time, 6Lowpan creates a Destination Oriented Directed Acyclic Graph (DODAG) using the edge router as a root node to set a route for traffic routing.

Hereinafter, with reference to FIG. 1, a resource discovery system of a sensor node in a limited network according to the present invention will be described in more detail.

1 is a schematic diagram of a resource discovery system for a sensor node within a restricted network according to an embodiment of the present invention.

As shown in FIG. 1, the resource discovery system 100 of a limited intra-network sensor node of the present invention includes a plurality of sensor nodes 120, a proxy 140, and a cloud server 160.

The sensor node 120 senses an event occurring at a location where the plurality of sensors are located in the network, transmits sensed information to the outside, and transmits a control message including available resource information to the edge router 122 To the proxy 140 via the Internet.

The resource information includes at least one of a device, a set of devices (for example, a thermometer and an air conditioner), an application, a content, a context, and a service as a physical component or a virtual component that provides useful information to a user can do.

The proxy 140 checks the resource information included in the control message received from the at least one sensor node 120, generates and manages a resource table including the checked resource information, , And transmits the resource table to the cloud server 160.

The cloud server 160 or the client requests the proxy 140 to transmit the resource table for the sensor node 120 in the network 10 and receives the resource table requested from the proxy 140.

Therefore, the proxy 140 receives the resource information for the at least one sensor node 120 constituting the restricted network 10 in advance to generate and manage the resource table, and thereby the cloud server 160 outside the network 10, Or when the client requests the resource table for the sensor node 120 in the network 10 without the proxy 140 performing data transmission and reception with the sensor node 120 for acquiring resource information, And the resource table being managed is transmitted to the cloud server 160 or the client, the power consumption of the sensor node 120 can be greatly reduced.

Hereinafter, a resource discovery method of a sensor node in a limited network according to another embodiment of the present invention will be described in detail with reference to FIG.

2 is a flowchart of a resource discovery method of a sensor node in a limited network according to another embodiment of the present invention.

As shown in FIG. 2, the method for discovering resources of a sensor node in a limited network according to the present invention includes: first, at least one sensor node 120 belonging to a network 10 to which a routing path is set, To the proxy 140 via the edge router 122 (S210).

In this case, the control message may include a DAO message. In order to secure the best path in the network 10 for going to the edge router 122 used as a root node, the DAO message And may include address information of all intermediate sensor nodes 120 passing through the edge router 122 as a destination. In the present invention, the control message further includes resource information, and the control message is transmitted to the edge router 122, Lt; RTI ID = 0.0 > 140 < / RTI >

Hereinafter, the control message transmitted to the proxy for creation of the resource table will be described in more detail with reference to FIG.

3 is a diagram illustrating a structure of a control message transmitted together with an IP header.

3, the control message 20 transmitted by the at least one sensor node 120 constituting the restricted network 10 to the proxy 140 may include a Destination Advertisement Object (DAO) message , And may be forwarded to the proxy 140 with an IP header.

In particular, since 6Lowpan to which the present invention is applied adopts IPv6, an IP address is automatically assigned to a large-scale sensor node 120 in consideration of a service in an object Internet environment, .

The control message 20 may have a structure of Type, Code, Checksum, and Option fields.

At this time, the type field indicates the cause of the error, and the size of 1 byte is allocated, and the contents about the request and response for determining whether the communication state is normal or not and the error report may be included. In particular, the error report includes information such as when a message does not reach the destination edge router, when a packet is requested to be sent slowly, when the routing path is reassigned, when the request time expires, when the header is invalid .

In addition, the code field indicates a specific reason for the error, which is also assigned a size of 1 byte. Details related to the code field can be confirmed by the following Table 1.

Code Explanation 0 When there is no network specified in the IP destination address (created in router only, routing failed) One The datagram was successfully transmitted on the router, but the last router could not communicate with the host (Reason: host shutdown, configuration error, IP setup error (occurred on the router connecting directly to the destination network) 2 This means that the datagram arrived at the destination host, but the IP datagram carries and the upper protocol identified by the protocol field in the IP header can not be used. The common upper protocol implemented in TCP / IP host is TCP, UDP, OSPF, and the problem can be solved by checking the availability code using the protocol ID of the IP header. 3 If the specified transport layer protocol (TCP, UDP) does not have a different protocol mechanism to notify the sender that the datagram can not be personalized (eg, a daemon on the server) 4 Because the MTU size of the network interface is less than the size of the datagram, a router is required to generate the datagram. However, if the DF flag is set to 1 in the datagram header, the router can not datagram DF. The DF flag is set to 1 for system boot message download from a WS with no disk to perform a TFTP file transfer 5 IP origination route option is used to create IP datagrams on routers, routers delete datagrams 6 Generated when the router detects that the destination network is unknown in the routing table 7 When the router detects that there is no destination host through the data link layer software on the network interface, 8 If the router detects that the host is isolated from the rest of the network, it will generate and disable it from RFC1812 9 Communication with the destination network is administratively prohibited 10 Communication with the destination host is administratively prohibited 11 Generated when the router can not send a datagram because the path in the routing table can not match the requested ToS value or the default ToS. 12 If the destination host can not be reached (similar to Code 11) 13 Administratively prohibited due to communication firewall 14 Host priority violation (created by the first hop router for the sender host) 15 Priority blocked (MSG sent to the sender by dropping datagrams with lower priority from the router)

In addition, the checksum field is a part for checking whether there is an error, a size of 2 bytes is allocated, and the option field is a part that does not fill in separate data and is left empty. However, the present invention may include resource information of the sensor node 120 in the empty space of the option field, or include caching information and observer information, or may include resource information, caching information, and observer information have.

The resource information may be a physical component or a virtual component that provides useful information to a user and may include a device, a set of devices (e.g., a thermometer and an air conditioner), an application, a content, a context, . In addition, the caching information refers to data that is frequently used or temporarily stores data having a complex search operation. Such caching information may be transmitted to the proxy 140 by setting the valid time of the routing path in the network 10. [ When the sensor node 120 frequently moves within the validity period of the predetermined routing path in the network 10, the caching information is transmitted to the proxy 140 based on 1/2 time of the effective time of the routing path ). In addition, the observation information is information for continuously monitoring whether or not the value of the sensing data sensed by the sensor node 120 exceeds a predetermined set value, and informing that the sensed data exceeds the preset value.

2, the proxy 140 verifies the resource information of the sensor node 120 included in the control message 20 received from the at least one sensor node 120 via the edge router 122 S220).

Next, a resource table including the resource information checked by the proxy 140 is generated and managed (S230). At this time, the resource table may be tabulated by matching the IP information of at least one sensor node 120 constituting the network 10 with the resource information of the sensor node identified through the control message 20, The IP information, the resource information, the caching information, and the observation information of the node 120 may be mutually matched and then tabulated.

However, if the proxy 140 fails to receive the control message including the resource information from the sensor node 120 via the edge router 122, the edge router corresponding to the end-device of the network 10 122 may transmit a control message including the resource information to the proxy 140 via the CoAP. The CoAP (Constrained Application Protocol) is a lightweight message protocol for Internet devices, and refers to a standardized protocol in a Constrained RESTful Environment (CoRE) working group for communication between Internet devices.

After the resource table is created using the resource information included in the control message 20 received by the proxy 140 and the management of the resource table is completed, the received resource information is successfully stored in the resource table The sensor node 120 transmits a confirmation message to the sensor node 120 via the edge router 122 in step S240. This acknowledgment message may be included in the option field in the form of an ACK message for the DAO message and transmitted to the sensor node 120 to notify the sensor node 120 that the received resource information is added in the resource table.

However, when the sensor node 120 in the network 10 fails to receive the ACK message for the DAO message from the proxy 140, the proxy 140 generates a time-out error The ACK message for the DAO message may be retransmitted to the sensor node 120.

After that, the cloud server 160 or the client requests the proxy 140 to transmit the resource table for the sensor node 120 in the network 10 through HTTPS, which is a security-enhanced web communication protocol (S250).

In response to the request of the cloud server 160, the proxy 140 transmits the resource table created and managed by the proxy 140 to the cloud server 160 or the client in operation S260.

That is, whenever the proxy 140 receives a request for transmission of a resource table from the cloud server 160 or a client, the proxy server 140 delivers the resource table managed by the proxy 140 to the cloud server 160 or the client. When the cloud server 160 or the client requests a resource table from the proxy 140 when there is no change in the configuration of the network 10 such that a new node participates in the network 10, Transmits the resource table managed by itself to the cloud server 160 or the client without performing a separate data transmission / reception process with the sensor node 120. Accordingly, since the sensor node 120 using the CR2012 or the like as a power source omits data transmission / reception with the cloud server 160 or the client to discover resources, the battery consumption of the sensor node 120 is greatly reduced The resource of the sensor node 120 can be easily found.

2, a new sensor node in the existing network 10 may newly participate due to the frequent movement of the sensor node 120. In this case, a method of discovering a resource for a new sensor node Let's take a closer look.

4 is a flowchart of a method of discovering a resource of a newly participating sensor node in a network.

As shown in FIG. 4, a method of discovering a resource of a sensor node newly participating in a restricted network according to another embodiment of the present invention includes a step of creating a new sensor node 120 in a network 10 already formed according to movement of the sensor node 120, In this case, first, the redirection of the routing path for traffic routing of the network 10 must be preceded.

Accordingly, the sensor node 120 newly participating in the network 10 broadcasts a first control message including its own network information and transmits the first control message to the edge router 122 (S310). At this time, the first control message may include an DIS message and a DIO message. The DIS message (DODAG Information Solicitation) message is transmitted to acquire information about nearby neighboring sensor nodes when a new node participates in an existing network or when redirection is required for a routing path in the network. Also, the DIO (DODAG Information Object) message can represent network information for each sensor node for DODAG subscription. At this time, 6Lowpan to which the present invention is applied generates a Destination Oriented Directed Acyclic Graph (DODAG) using an edge router as a root node, and generates a Destination Oriented Directed Acyclic Graph (DODAG) Is set.

Accordingly, the edge router 122 checks network information for each sensor node 120 included in the DIO message of the first control message received by the edge router 122, and performs routing in the network 10 through DODAG subscription based on the checked network information Path is set (S320).

When a new sensor node has newly established a routing path to the participating network 10, at least one sensor node 120 transmits a second control message including resource information to the edge router 122 via the edge router 122 To the proxy 140 (S330). The second control message may include a DAO message, which is used by the destination advertisements object (DAO) to determine the best route in the network 10 to go to the edge router 122 used as the root node. And may include address information of all intermediate sensor nodes 120 passing to a destination edge router 122. Particularly, in the present invention, resource information may be further included in the option field of the second control message and may be transmitted to the proxy 140 through the edge router 122. [

In addition, the at least one sensor node 120 may additionally generate and retransmit a second control message including caching information and observation information, or may further include caching information and / And can include observation information together.

After that, the proxy 140 checks the resource information included in the second control message (S340), creates a resource table including the checked resource information, and manages the resource table (S350). At this time, as the new sensor node 120 in the network 10 newly joins the resource table in the state where the resource table has been previously created and managed, the resource table having the IP address information for the new sensor node 120 And the resource information are updated.

After generating and managing a resource table using the resource information included in the second control message received by the proxy 140, the proxy 140 generates a confirmation message to the sensor node 120 through the edge router 122 (S360). This acknowledgment message may be included in the option field in the form of an ACK message for the DAO message and transmitted to the sensor node 120 to notify the sensor node 120 that the received resource information is added in the resource table.

The cloud server 160 or the client that wishes to discover the resource for the sensor node 120 of the restricted network 10 can then transmit the resource table for the sensor node 120 of the network 10 to the proxy 140 (S370).

In response to the request from the cloud server 160 or the client, the proxy 140 transmits the resource table managed by the proxy 140 to the cloud server 160 or the client in step S380.

As a result, the cloud server 160 or the client can effectively discover the resource without directly communicating with at least one sensor node 120 in the network 10 to discover the resource. Particularly, at this time, since the sensor node 120 does not perform data communication with the cloud server 160 or the client separately, the battery consumption can be greatly reduced.

As described above, according to the method and system for discovering resources of a sensor node in a limited network according to the present invention, resource information of a plurality of sensor nodes constituting a limited network is tabled before a request of a cloud server, The proxy server can transmit the table generated by the proxy to the cloud server so that the cloud server can easily discover the resource of the sensor node without direct communication with the sensor node.

In addition, according to the method and system for discovering resources of a sensor node within a limited network according to the present invention, a cloud server requests transmission of a resource table to a proxy, so that the cloud server performs direct data transmission / reception with each sensor node constituting the restricted network The power consumption of data transmission / reception between the cloud server and the sensor node can be greatly reduced.

It will be apparent to those skilled in the relevant art that various modifications, additions and substitutions are possible, without departing from the spirit and scope of the invention as defined by the appended claims. The appended claims are to be considered as falling within the scope of the following claims.

120: sensor node 122: edge router
140: Proxy 160: Cloud server
20: Control message

Claims (5)

Transmitting at least one sensor node belonging to a network having a routing path to a proxy through a edge router with a control message including resource information;
The proxy verifies the resource information included in the control message, and generates and manages a resource table including the checked resource information;
The cloud server requesting the proxy to transmit a resource table for the sensor node of the network; And
Sending, by the proxy, the resource table to the cloud server in response to a request from the cloud server;
The method comprising the steps of:
The method according to claim 1,
The control message
Wherein the resource information is included in an option field of a message structure.
The method according to claim 1,
The step of the at least one sensor node belonging to the network for which the routing path is set to transmit the control message including the resource information to the proxy via the edge router
Wherein the at least one sensor node further includes caching information and observation information in the control message, and transmits the caching information and the observation information to the at least one sensor node.
The method according to claim 1,
The resource table
Wherein when the new sensor node in the network is searched, the resource information of the searched new sensor node is updated.
At least one sensor node for transmitting a control message including resource information to a proxy via an edge router;
A resource table included in the control message received from the at least one sensor node is checked and a resource table including the checked resource information is generated and managed, and when requesting transmission of the cloud server, the resource table is transmitted to the cloud server Proxy; And
A cloud server for requesting transmission of a resource table for a sensor node of a network to which a routing path is set by the proxy and receiving a requested resource table;
Wherein the sensor nodes are located within a restricted network.

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