KR101208400B1 - Node apparatus for mixed mode routing in rpl routing protocol and method thereof - Google Patents

Abstract

PURPOSE: A mixed mode routing node in an RPL(routing protocol for low power lossy networks) routing protocol and method thereof are provided to construct an effective and flexible network according to a surrounding environment by embodying a mixed mode within a storing mode or a non-storing mode. CONSTITUTION: A DIO(data information object) message processing unit(108) converts the set downward routing mode according to the set downward routing mode conversion condition and the downward routing mode setting information of a DIO message. A DAO(data access object) message processing unit(110) updates a routing table or converts a parent address of a transit information option of the DAO message according to the target prefix of an RPL target option, a transmission address, and the downward routing mode. A data packet processing unit(112) transmits the data packet to a next node according to routing information. [Reference numerals] (102) Setting unit; (104) Packet creation unit; (106) Packet transmission and reception unit; (108) DIO message processing unit; (110) DAO message processing unit; (112) Data packet processing unit

Description

Mixed Mode Routing Nodes and Methods in the RPC Routing Protocols {NODE APPARATUS FOR MIXED MODE ROUTING IN RPL ROUTING PROTOCOL AND METHOD THEREOF}

The present invention relates to a technique for simultaneously using a storage mode and a non-storing mode in an IPv6 Routing Protocol for Low Power and Lossy Networks (RPL) routing protocol for low power, high loss networks.

Routing Over Low Power and Lossy networks (ROLLs), one of the working groups of the International Organization for Standardization Internet Engineering Task Force (IETF), are involved in routing algorithms in the area of low power and lossy networks (LLNs). Research and standardization.

The LLN region consists of multiple nodes, which have limited process power, memory capacity, and battery operation. Thus the link between nodes is unstable and has low bandwidth (see IEEE 802.15.4). In addition, as the TCP / IP stack rises on nodes and the introduction of IPv6 addressing (see IETF 6lowpan working group, RFC-4919, RFC 4944), new routing protocols for LLN nodes with IPv6 addressing are needed. It became. The ROLL Working Group has proposed IPv6 Routing Protocol for Low Power and Lossy Networks (RPL), an IPv6 routing protocol for low power, high loss networks.

RPL uses the ICMPv6 RPL Control Message to form the Destination Oriented Directed Acyclic Graph (DODAG) with nodes in the LLN region. Inside DODAG, up and down routes are created / updated based on the DODAG root and provide a smooth routing path to the destination address. (ICMPv6 RPL control messages include DODAG Information Object (DIO), DODAG Information Solicitation (DIS), Destination Advertisement Object (DAO), and Destination Advertisement Object Acknowledgement (DAO-ACK).)

There are two methods for creating / updating a downstream route: storage mode and non-storing mode. The storage mode is a form in which all nodes except the leaf node have a routing table. When some nodes in the LLN have low memory capacity and low processing power, it may cause early battery drain and memory problems. In the non-storage mode, only the DODAG route has a routing table. When transmitting a downlink data packet, all paths up to the destination address are added / inserted into the header. In this case, there is a problem that the length of the packet increases in proportion to the number of multihops leading up to the final destination. For example, if the distance to the destination is 20 hops, the packet is wasted because 19 addresses must be entered in the header.

Therefore, in order to solve this problem, a mixed mode for properly mixing and using a storage mode and a non-storing mode in one LLN is required.

RPL: IPv6 Routing Protocol for Low power and Lossy Networks (draft-ietf-roll-rpl-19, http://datatracker.ietf.org/doc/draft-ietf-roll-rpl/) Terminology in Low power And Loosy Networks (draft-ietf-roll-terminology-05, http://datatracker.ietf.org/doc/draft-ietf-roll-terminology/) RPL Objective Function Zero (draft-ietf-roll-of0-20, http://datatracker.ietf.org/doc/draft-ietf-roll-of0/) An IPv6 Routing Header for Source Routes with RPL (draft-ietf-6man-rpl-routing-header-03, http://datatracker.ietf.org/doc/draft-ietf-6man-rpl-routing-header/)

An object of the present invention is to configure a flexible and efficient network according to the surrounding environment by using a mixed storage mode and non-storage mode in one network.

The mixed mode routing node in the RPL routing protocol, which is a routing protocol for a low power high loss network, according to an embodiment of the present invention for solving the above problems, receives a DIO message, and routes the downlink included in the received DIO message. A DIO message processor configured to set a down routing mode of the routing node or change a preset down routing mode according to mode setting information and a preset routing mode change condition; Receive a DAO message, and according to the target prefix of the RPL target option (RPL Target Option) of the received DAO message, the transmission address that transmitted the DAO message and the downlink routing mode of the routing node of the DAO message A DAO message processing unit for changing a parent address of a Transit Information Option or updating a routing table; And receiving a data packet, obtaining a next address to transmit the data packet from a source route header (SRH) included in the data packet, and searching for the next node address in a neighbor table or a routing table. And a data packet processor for transmitting the data packet according to the result.

On the other hand, the mixed mode routing method in the RPL routing protocol according to an embodiment of the present invention for solving the above problems, receiving a DIO message, downlink routing mode configuration information included in the received DIO message and the predetermined routing Setting a downlink routing mode of the routing node or changing a preset downlink routing mode according to a mode change condition; Receive a DAO message, and according to the target prefix of the RPL target option (RPL Target Option) of the received DAO message, the transmission address that transmitted the DAO message and the downlink routing mode of the routing node of the DAO message A second step of changing a parent address of a Transit Information Option or updating a routing table; And receiving a data packet, obtaining a next address to transmit the data packet from an IPv6 Routing Header for Source Routes with RPL included in the data packet, and receiving the next node. And transmitting the data packet to a next node according to a result of retrieving an address from a neighbor table or a routing table.

According to embodiments of the present invention, by implementing a mixed mode in which the storage mode and the non-storage mode are mixed in one network, a flexible and efficient network may be configured according to the surrounding environment.

1 is a block diagram illustrating a configuration of a mixed mode routing node according to an embodiment of the present invention.
2 is a diagram illustrating a structure of a DIO message used in an RPL.
3 is a diagram illustrating a structure of a DAO message used in an RPL.
4 is a diagram illustrating a structure of an RPL Target Option added to an option field of a DAO message.
5 is a diagram illustrating the structure of a Transit Information Option added to an option field of a DAO message.
6 is a flowchart illustrating a process of generating and transmitting a DIO message in a DODAG route in a mixed mode routing method according to an embodiment of the present invention.
7 is a flowchart illustrating a method of processing a DIO message in a mixed mode routing method according to an embodiment of the present invention.
8 is a flowchart illustrating a DAO message processing method in a mixed mode routing method according to an embodiment of the present invention.
9 is a flowchart illustrating a downlink data packet processing method in a mixed mode routing method according to an embodiment of the present invention.
10 is an exemplary diagram for explaining an example of setting a DODAG and an upstream route path.
FIG. 11 is a diagram illustrating an example of forming a down routing table of a DODAG route and node 2 when the down routing mode is a storage mode in the DODAG set in FIG. 10.
FIG. 12 is a diagram illustrating the flow (dotted line) of a DAO message for establishing a downlink route path when the downlink routing mode is a non-storage mode in the DODAG set in FIG. 10.
FIG. 13 is a diagram illustrating an example of forming a down routing table of a DODAG route when the down routing mode is a non-storage mode in the DODAG set in FIG. 10.
FIG. 14 is a diagram illustrating a DODAG configured with a mixed down mode in a mixed mode, an uplink path (solid line), and a flow of DAO messages (dashed lines) for establishing a downlink path.
FIG. 15 is a diagram illustrating an example of forming a down routing table of a DODAG route and node 10 in the DODAG in the mixed mode shown in FIG. 14.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. However, this is merely an example and the present invention is not limited thereto.

In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intention or custom of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

The technical idea of the present invention is determined by the claims, and the following embodiments are merely a means for effectively explaining the technical idea of the present invention to a person having ordinary skill in the art to which the present invention belongs.

Prior to describing the present invention, a process of configuring an upward route and a downward route in RPL will be briefly described.

First, in RPL, an upward route is created through the rank value in the DIO message as the DIO message is propagated to other nodes. RANK is a kind of link quality between nodes, and the measurement matrix may be the number of hops, the Expected transmission count (ETX), or the like. The method of calculating the RANK value between nodes, measurement values, and parent node selection criteria are determined by an object function, which is described in detail in ietf-roll-of0. The node receiving the DIO message selects the parent node of its own node as the RANK field value in the DIO message (generally, selects the node that sent the DIO message containing the lowest RANK value as the parent) and accumulates the RANK value. The DIO message is resent to neighboring nodes by updating the calculated RANK result. This creates a tree-structured LLN topology with the DODAG route at the top, creating an upward route. The DODAG route also resends the DIO message periodically through a timer, which flexibly copes with topology / routing information changes due to node addition, deletion, and change.

Next, there are two methods of creating / updating a downward route, a storage mode and a non-storing mode, each of which is based on a value described in a mode of operation (MOP) field of a DIO message. Is determined accordingly. That is, the down routing mode of the nodes is determined according to the MOP value included in the propagation of the DIO message. The transmission destination of the DAO message varies depending on the mode, and the downlink routing information is collected from the received DAO message.

In storage mode, all nodes except the leaf node individually create / maintain a routing table for their subnodes. At each node, a DAO message is generated and sent to its parent node. In this case, as the target prefix of the RPL Target Option of the DAO message, the address of the node that first generates the DAO is input, and the parent address of the Transit Information Option is omitted. The generated DAO message is sent / retransmitted to its parent. Nodes receiving the DAO message create / update the routing table using the address of the node that sent the DAO message and the address of the first DAO generating node recorded in the Target prefix of the RPL Target Option. The routing table contains a destination address and a next address entry that must be sent to arrive at the destination address (see ietf-roll-rpl for details).

On the other hand, in non-storage mode, only the DODAG root creates / maintains the routing table for the nodes in the DODAG. Each node in non-storage mode generates DAO message as follows. In the Target Prefix of the RPL Target Option, the address of the node that first generates the DAO is input. In the parent address of the Transit Information Option, the address of its best parent is input. In this case, the best parent may be determined by the above-described object function. For example, the best parent may be determined such that the number of message transfer hops through the uplink is minimized. The generated DAO message is sent with the DODAG route as the destination. The DODOA route receiving the DAO message creates / updates a routing table using the parent address of the Transit Information Option containing the address of the first DAO creation node and the parent node address contained in the target prefix of the RPL Target Option of the DAO message.

When transmitting a downlink packet, the DODAG route searches the source routing path from the routing table created above to the destination address and generates a source route header (see ietf-6man-rpl-routing-header). do. The SRH is inserted into the downlink packet, and the nodes receiving the downlink data packet including the SRH process the SRH, obtain a target address to transmit the packet, and transmit the packet to the obtained target. Through such SRH processing, the packet is transmitted to the final destination along the source route path.

1 is a block diagram illustrating a configuration of a mixed mode routing node 100 according to an embodiment of the present invention. In the present invention, the mixed mode routing node 100 is a device for constructing a low power and lossy network, and the plurality of mixed mode routing nodes 100 are configured to configure a tree structured network using RPL. do.

As shown, the mixed mode routing node 100 according to an embodiment of the present invention is the setting unit 102, packet generation unit 104, packet transmission and reception unit 106, DIO message processing unit 108, DAO message The processor 110 and the data packet processor 112 are included.

The setting unit 102 sets an initial down routing mode of the mixed mode routing node 100, whether a mixed mode is activated, a condition for changing the down routing mode when the mixed mode is activated, and the like. The above-described setting values may be input to the setting unit 102 by, for example, an administrator of the network, and for this purpose, the setting unit 102 may include an appropriate input interface.

As described above, the down routing mode is divided into a storage mode and a non-storing mode, and the initial down routing mode is executed in a mode in which the mixed mode routing node 100 is executed in the first execution. The setting value for whether or not. The mixed mode activation value is a value for determining whether the mixed mode routing node 100 operates in a mixed mode in which the downlink routing mode is changed as needed. For example, when the mixed mode routing node 100 operates in the mixed mode, If 0, it may be configured to operate in any of the existing RPL mode stored mode or non-save mode. The condition for changing the down routing mode is information about the condition for changing the down routing mode in the mixed mode, for example, when a node belonging to the LLN reaches a certain rank or a certain rank from the DODAG root node. Hereinafter, or in the case of an address of a specific node, it may be configured to change the downlink routing mode. However, this is only one example, and the administrator may set an appropriate change condition as necessary, and each mixed mode routing node 100 may change the down routing mode from the storage mode to the non-save mode according to the set change condition. Alternatively, you can change from save mode to save mode.

The packet generator 104 generates an ICMPv6 RPL control message (DIO, DIS, DAO, DAO-ACK) and a source route header (hereinafter referred to as SRH). 2 is a diagram illustrating a structure of a DIO message. A value of a mode of operation (MOP) field of each field of the illustrated DIO message is set with reference to the initial downlink routing mode set by the setting unit 102. In addition, the mixed mode flag selects and records 1 bit among unused Flag or Reserved fields of the DIO, and the value refers to a mixed mode activation setting value of the setting unit 102.

3 is a diagram illustrating the structure of a DAO message. In the case of a DAO message, various option headers, such as an RPL target and a Transit Information, may be added.

4 is a diagram illustrating a structure of an RPL Target Option added to an option field of a DAO message. In the Target Prefix of the RPL Target Option, the address of the node (routing node) that initially generates the DAO message is entered. FIG. 5 is a diagram illustrating the structure of a Transit Information Option added to an option field of a DAO message. In the Parent Address field of the Transit Information Option, an address of a parent node of a non-storing mode is input. Omit.

When the SRH is in the non-storing mode, path information is included so that a downlink packet can be smoothly transmitted to a destination address. In the existing RPL protocol, SRH is added to the data packet header only in the non-storing mode. However, in the present invention, since the storing / non-storing mode is mixed in one DODAG, SRH is added to the data packet header regardless of the mode. In this case, the SRH generation algorithm follows a conventional algorithm (ietf-6man-rpl-routing-header, An IPv6 Routing Header for Source Routes with RPL).

In addition, it is noted that parts not specifically mentioned in the DIO message, the DAO message, and the SRH follow the existing algorithm as it is.

The packet transceiver 106 transmits and receives a packet. At this time, the transmission timing is determined by a timer (not shown). The timer operation follows the trickle algorithm used by RPL (see RFC 6206 for details).

The DIO message processor 108 receives the DIO message and generates / updates its own DODAG information (MOP-downward routing mode, DODAG ID, etc.) using the received DIO message information. The preset downlink routing mode is changed according to the downlink routing mode setting information included in the received DIO message and a preset routing mode change condition.

Specifically, the DIO message processing unit 108 is set to a mode in which the MOP of the received DIO message supports a downward route (for example, when the MOP value is 0, the downward route is not supported in the RPL), and the mixed mode It is determined whether the flag is activated. Whether to set the down routing mode of the received DIO message may be determined from a value recorded in the MOP field of the DIO message. Also, whether the mixed mode flag of the received DIO message is activated is an unused flag or a reserve of the DIO message. It can be known from the bit set by the packet generation unit 104 in the reserved field as the mixed mode flag.

If the down routing mode is set and the mixed mode flag is activated, the DIO message processing unit 108 determines whether the down routing mode change condition set in the setting unit 102 is satisfied, and the change condition is satisfied. In this case, the preset downlink routing mode is changed. That is, when the preset downlink routing mode is a storage mode, it is changed to a non-storing mode, and when the preset downlink routing mode is a non-storage mode, it is changed to a storage mode. Accordingly, according to the present invention, unlike the conventional method, the non-storing mode and the storing mode are mixed in one DODAG according to the setting value and the change condition of the DIO message.

The DAO message processing unit 110 receives the DAO message, and transmits the DAO message according to a target prefix of the received DAO message, a transmission address for transmitting the DAO message, and a downlink routing mode of the routing node. Change the parent address of the option or update the routing table.

In detail, the DAO message processor 110 determines whether the DAO message processor 110 is a DODAG root node when receiving a DAO message. At this time, when the node (routing node) receiving the DAO message is a DODAG route, the DAO message processing unit 110 determines whether the parent address of the Transit Information Option (TIO) of the received DAO message is empty. If the parent address is empty, the DAO message processing unit 110 generates / updates the routing table by generating a routing table in the Storing mode or updating an existing routing table. (Refer to draft-ietf-roll-rpl for the details of the routing table.) That is, the address of the transmitting node that sent the DAO message is recorded in the next address of the routing table, and in the destination prefix of the RPL Target Option in the destination address. The recorded address is recorded. On the contrary, when the parent address is not empty, the DAO message processing unit 110 generates / updates the routing table by creating a routing table in the non-storing mode or updating an existing routing table. That is, the parent address of the Transit Information Option is stored in the next address of the routing table, and the address recorded in the Target Prefix of the RPL Target Option is recorded in the destination address.

If the node receiving the DAO message is not the DODAG root node, it is processed as follows. First, when the down routing mode of the node that receives the DAO message is the non-storage mode, and the target prefix address of the RPL Target Option of the DAO message and the address of the transmitting node that transmits the DAO message match, the DAO message processing unit ( 110 inputs its own address (ie, the DAO receiving node) to the Parent Address of the TIO of the DAO message, and transmits the input DAO message to the DODAG root.

On the contrary, when the target prefix address of the RPL Target Option of the DAO message and the address of the transmitting node that transmits the DAO message do not match, the DAO message processing unit 110 may transmit the DAO to the Parent Address of the Transit Information Option of the DAO message. Enter the address of the sending node that sent the message, and send the entered DAO message to the DODAG route.

On the other hand, when the downlink routing mode of the routing node 100 receiving the DAO message is a storage mode, the DAO message processing unit 110 receives the RPL Target Option of the received DAO message and the address information of the DAO transmitting node. Update the routing table of the routing node by using, and transmit the received DAO message to a higher node. At this time, the address of the transmitting node that has transmitted the DAO message is recorded in the next address of the routing table, and the address of the node stored in the RPL Target Option is recorded in the destination address.

The data packet processing unit 112 receives a data packet, obtains a next address (next address) to transmit the data packet from a source route header (SRH) included in the data packet, and a downlink routing mode of the routing node. In accordance with the method, obtain routing information corresponding to the next node address from a neighbor table or a routing table, and transmit the data packet to the next node according to the obtained routing information.

When the data packet is received, the data packet processing unit 112 first obtains a next address to transmit the data packet from the SRH of the received data packet (ie ietf for a process of obtaining a next address from SRH). -6man-rpl-routing-header). In the conventional non-storing mode, since the source route path included in the SRH includes all the addresses of the route to the final destination, the packet can be delivered only with the corresponding information. However, in the mixed mode, the non-storing mode and the storing mode are mixed so that only the source route path of the SRH cannot be reached to reach the final destination, so routing is performed through the following process.

First, the data packet processing unit 112 searches the neighbor table for the next node address obtained from the SRH to determine whether the next node address exists around 1-hop. The neighbor table is a table that records information of neighboring nodes that can reach 1-hop in the routing node 100 receiving the packet. If the next node address exists in the neighbor table, the data packet processor 112 transmits the data packet to the next node.

If the next node address does not exist in the neighbor table, the data packet processing unit 112 next searches the next node address in its routing table. If routing information corresponding to the next node address is stored in a routing table, the data packet processor 112 transmits the data packet according to the routing information obtained from the routing table.

However, if the next node address does not exist in the routing table or the routing table itself does not exist (if the node is in a non-storing mode), the data packet processor 112 discards the received data packet. (drop) and wait for the next packet to be received.

6 is a flowchart illustrating a process of generating and transmitting a DIO message at a DODAG route 600 in a mixed mode routing method according to an embodiment of the present invention.

First, the setting unit 102 of the DODAG root node, the initial downward routing mode (mixed mode) of the mixed mode routing node 100, whether the mixed mode (mixed mode) activation and the conditions for changing the down routing mode when the mixed mode is activated Next, the packet generation unit 104 generates a DIO message with reference to the setting value of the setting unit 102 (S604). Finally, the packet transmitter / receiver 106 transmits the DIO message generated by the packet generator 104 to surrounding nodes (S606).

7 is a flowchart illustrating a method of processing a DIO message in a mixed mode routing method according to an embodiment of the present invention.

When the routing node 100 receives the DIO message (S702), the routing node 100 first compares the version number of the received DIO message with its own version number (S704). If the version number of the received DIO message is smaller than the version number owned by the comparison result of step S704, the message is discarded and the other DIO message is waited for to be received (S706).

If the version number of the received DIO message is greater than the owned version number as a result of the comparison of step S704, the DODAG information (MOP, DODAG ID, RPL InstanceID, etc.) is generated and updated by using the received DIO message. (For more information, refer to ietf-roll-rpl.) The rank value between nodes is calculated using an object function, and its best parent is determined based on the calculated rank value (S708).

Thereafter, the routing node 100 sets the downward routing mode of the received DIO message to the storage mode or the non-storage mode (ie, the MOP value is not 0), and the mixed mode flag is set. It is determined whether or not it is activated (S710).

If it is determined in step S710 that the downlink routing mode is set to a storage mode or a non-save mode, and the mixed mode flag is activated, it is next determined whether a preset downlink routing mode change condition is satisfied (S712). If the routing mode change condition is satisfied, the preset downlink routing mode is changed (S714). In more detail, when the downlink routing mode set by the received MOP field of the DIO message is a storage mode, it is changed to a non-storing mode, and when the non-storage mode is a storage mode. However, it is noted that even if the down routing mode is changed in this step, the down routing mode recorded in the MOP field of the received DIO message is not changed. That is, the DIO message transmitted in step S718 to be described later maintains the MOP originally recorded, and the rank value is updated and transmitted.

Thereafter, the routing node 100 updates the rank value of the received DIO message (S716). The DIO message is transmitted to surrounding nodes (S718).

8 is a flowchart illustrating a DAO message processing method in a mixed mode routing method according to an embodiment of the present invention.

As described above, the DAO message is generated in the packet generator of each node. The target prefix of the RPL Target Option of the generated DAO is inputted with the address of the node that first generates the DAO message. If the node generating the DAO message is in the non-storing mode, the DODAG parent address is inserted into the generated Transit Information Option of the DAO. In the storing mode, the parent address of the Transit Information Option of the DAO is omitted.

When the DAO message generated as described above is received (S802), the routing node 100 first determines whether it is a DODAG root node (S804). If it is determined that the self is not the DODAG route, it determines next to its downlink routing mode (S806).

If it is determined in step S806 that the downlink routing mode is a non-storing mode, next, whether the target prefix address of the RPL Target Option of the DAO message and the address of the transmitting node that transmitted the DAO message match; It is determined (S808).

If it is determined in step S808 that the Target Prefix address of the RPL Target Option of the DAO message and the address of the transmitting node that has transmitted the DAO message match, the routing node 100 determines the Parent Address of the Transit Information Option of the DAO message. The routing node enters the address of the routing node (S810), and transmits the DAO message to the DODAG route (S812).

If it is determined in step S808 that the target prefix address of the RPL Target Option of the DAO message and the address of the transmitting node that has transmitted the DAO message do not match, the DAO message is set to the Parent Address of the Transit Information Option of the DAO message. Input the address of the transmitting node that has transmitted the data (S814), and transmit the DAO message to the DODAG route (S812).

On the other hand, if it is determined in step S806 that the downlink routing mode of the routing node is storing mode, the routing table of the routing node is updated using the RPL Target Option of the received DAO message and the address information of the transmitting node. (S816). That is, the address of the transmitting node that has transmitted the DAO message is recorded in the next address of the routing table, and the address recorded in the Target Prefix of the RPL Target Option is recorded in the destination address. Thereafter, the DAO message is transmitted to its DAO parent (S812). A DAO parent generally means its parent.

On the other hand, when the determination result of step S804, if the root of the DODAG itself, it is determined whether the value of the Transit Information Option of the DAO message is empty (S818). If the value is empty, a routing table is generated / updated by a method of generating or updating a routing table in a storing mode using the RPL Target Option of the received DAO message and address information of the DAO transmitting node (S820). ). That is, the address of the transmitting node that has transmitted the DAO message is recorded in the next address of the routing table, and the address recorded in the Target Prefix of the RPL Target Option is recorded in the destination address. Otherwise, the routing table is created or modified in the non-storing mode using the target prefix of the RPL Target Option and the parent address of the Transit Information Option of the received DAO message (S822). That is, the parent address of the TIO is stored in the next address of the routing table, and the address recorded in the Target Prefix of the RPL Target Option is recorded in the destination address.

9 is a flowchart illustrating a downlink data packet processing method in a mixed mode routing method according to an embodiment of the present invention.

When an RPL border router (usually a DODAG route) receives a downlink packet inside / outside the LLN, the DODAG route inserts route information to the source router header (SRH) leading to the final destination and sends data packets along this route. send. However, in the mixed mode according to the present invention, the storing mode and the non-storing mode are mixed, and the path information about the nodes in some storing modes is not contained in the SRH. Therefore, to solve this problem, the following method is followed.

As shown, the downlink data packet processing method depends on whether the routing node 100 receiving the packet is a DODAG route (RPL border router).

First, when a data packet is received through the DODAG route (S902, S904, i.e., when a downlink packet is received from inside / outside the LLN), the routing node 100 sends the route information to the final destination in the source router header (SRH). In step S906, the SRH is processed to calculate a next address to transmit a data packet (S908).

If the node receiving the packet is not the DODAG route, the routing node 100 first determines whether the corresponding data packet is the final destination from the destination address of the received data packet (S910). If it is the final destination of the received data packet, the algorithm is terminated because the data packet has successfully arrived at the desired final destination. If it is not the final destination of the data packet, it is next determined whether the next address of the data packet and its address match (S912). As a result of determination, if the next address of the data packet matches its own address, a new next address for reaching the final destination is required, and the new next address is calculated by processing the SRH of the data packet header (S908). Since the processing method is the same as the existing method (An IPv6 Routing Header for Source Routes with RPL), a detailed description thereof will be omitted.

Next, the routing node 100 searches its neighbor table and checks whether a next address exists around a 1 hop criterion (S914). If it is determined in step S914 that the next address exists in the neighbor table, since the next address exists in the periphery thereof, the data packet is transmitted to the next address (S920).

If it is determined in step S914 that the next address does not exist in the neighbor table, it is determined whether a mixed mode is activated next (S916). It is determined whether the address exists in the routing table (S918).

As a result of the determination in step S918, when the next address exists in the routing table, routing information corresponding to the next address is obtained from the routing table, and the data packet is transmitted to a node according to the obtained routing information. (S920).

On the other hand, if the mixed mode is not activated as a result of the determination in step S912, or if the next node address does not exist in the routing table or the routing table itself does not exist, as a result of the determination in step S914, Drop the data packet and return to the beginning waiting for the next data packet.

10 to 15 are exemplary diagrams for explaining the difference between the down routing method of the storage mode, non-storage mode and mixed mode according to the present invention. In each of the drawings, the address of each node originally has an IPv6 addressing system, but for convenience of description, it is noted that the address assigned to each node replaces the address of each node. Also, in each figure, the DODAG route is node 1, and the inter-node arrows (solid lines) indicate upward route paths formed by the DIO.

First, FIG. 10 is an exemplary diagram illustrating an example in which a DODAG and an upstream route path are set to explain a difference in a downlink routing method in a storage / non-storage mode.

FIG. 11 is a diagram illustrating an example of forming a down routing table of a DODAG route and node 2 when the down routing mode is a storage mode in the DODAG set in FIG. 10. In the downlink storage mode, a DAO message formed at each node is transmitted targeting its own parent node. In addition, the routing table has all nodes except the leaf node, and in this example, the routing table is formed in all nodes except 3, 4, 8, and 14. 11 shows an example of the routing table of the DODAG route and node 2. When an RPL border router (usually a DODAG route) receives a downlink packet inside / outside the LLN, it refers to the routing table of each node to reach its final destination.

FIG. 12 is a diagram illustrating a flow (dotted line) of a DAO message for establishing a downlink route path when the downlink routing mode is a non-storage mode in the DODAG set in FIG. 10. In the non-storage mode, all DAO messages formed at each node are sent with the target of the DODAG route. Accordingly, the routing table is generated only in the DODAG root, which is shown in FIG. At this time, if a packet is transmitted from the DODAG root to the node 13, the path included in the SRH is as follows.

2->5->6->7->9->10->11->12-> 13

When an RPL border router (usually a DODAG route) receives a downlink packet inside / outside the LLN, it reaches the final destination along the path included in the SRH.

FIG. 14 is an exemplary diagram representing a DODAG configured with a mixed down mode in a mixed mode, an uplink path (solid line), and a flow of a DAO message (dashed line) for establishing the downlink path, wherein the initial down routing mode is a storage mode, and FIG. RANK / 3) A change condition is set to change the down-routing mode whenever the result of mode 2 is 1 (assuming RANK = hop count) or when the node address is 6,7,8,9,13,14. The case is shown. Accordingly, in the drawing, the storage mode nodes are 1, 2, 3, 4, 5, 10, 11, and 12, and the non-storage mode nodes are 6, 7, 8, 9, 13, and 14. At this time, the nodes having the downlink routing table are 1,2,10,11. Accordingly, as shown by the dotted arrow, the node in the storage mode transmits the DAO message to its parent node, and the node in the non-storage mode transmits the DAO message to the DODAG root node.

As described above, in the case of the DAO message, the address of the node that first generates the DAO message is input in the Target Prefix of the RPL Target Option, and in the Parent Address field of the Transit Information Option, the address of its parent node is input in the non-storage mode. The storage mode is omitted.

For example, since node 14 is in the non-storage mode, it is input as follows.

Target prefix of RPL Target Option = 14

Parent Address of TIO = 13

Since node 12 is in storage mode, the first DAO message is generated as follows.

Target prefix of RPL Target Option = 12

Parent Address of TIO = NULL

When the DAO message generated at the node 12 reaches node 9, the node 9 is in a non-storage mode, and the node (node 10) that sent the DAO message and the target prefix of the RPL target option (node 12) do not match. Therefore, the address of the node that transmitted the DAO message is entered in the Parent Address of the Transit Information Option. That is as follows.

Target prefix of RPL Target Option = 12

Parent Address of TIO = NULL-> 10

Meanwhile, in the case of node 10, since the storage mode, the first DAO message is generated as follows.

Target prefix of RPL Target Option = 10

Parent Address of TIO = NULL

When the DAO message generated at the node 10 reaches node 9, the node 9 is in the non-storage mode, and the node (node 10) that transmits the DAO message and the target prefix of the RPL target option (node 10) match. Enter your own address in Parent Address of Transit Information Option. That is as follows.

Target prefix of RPL Target Option = 12

Parent Address of TIO = NULL-> 9

In the same process, when a DAO message is transmitted from each node through the algorithm shown in FIG. 8, a routing table is generated based on this. In the example shown in FIG. 14, a routing table is created at node 1, which is a DODAG route, and at nodes 2, 10, and 11, which are not leaf nodes among storage mode nodes. In other words, it can be seen that the number of routing table holding nodes is reduced in the mixed mode compared to the storage mode. An example of the routing table generated at the DODAG route and node 10 is shown in FIG. 15.

On the other hand, in this case, the SRH path when transmitting a data packet from the DODAG root to the node 13 is as follows.

2->5->6->7->9->10->12-> 13

That is, it can be seen that the size of the SRH is reduced in the mixed mode compared to the non-storage mode. In addition, the number of nodes with routing tables is reduced compared to the storage mode.

Next, in the case of the DODAG formed in the mixed mode as shown in FIG. 14, a process of transmitting a packet received at the DODAG root to the node 13 according to SRH will be described.

First, the DODAG route (node 1) receiving the data packet generates an SRH destined for node 13, and extracts a next address (node 2) from the SRH. Since node 2 is stored in the neighbor table of node 1, node 1 transmits the data packet to node 2.

Node 2 extracts a new next address (node 5) from the SRH of the received packet and sends the data packet to node 5 with reference to the neighbor node table.

Node 5 extracts the new next address (node 6) from the SRH of the received packet and sends the data packet to node 6 with reference to the neighbor node table.

Node 6 extracts a new next address (node 7) from the SRH of the received packet and sends the data packet to node 7 with reference to the neighbor node table.

Node 7 extracts the new next address (node 9) from the SRH of the received packet and sends the data packet to node 9 with reference to the neighbor node table.

Node 9 extracts a new next address (node 10) from the SRH of the received packet and sends the data packet to node 10 with reference to the neighbor node table.

Node 10 extracts a new next address (node 12) from the SRH of the received packet. In order to transmit the data packet, a neighbor table is first referred to. However, since node 12 does not exist in the neighbor table of node 10, it next refers to its own routing table. As shown in FIG. 15, node 10 transmits the data packet to node 11 since the next address for transmitting the packet to node 12 in node 10's routing table is node 11.

Node 11 retrieves the neighbor table because the next address of the received packet is node 12 (that is, without extracting the new next address from SRH because it is not the destination), and the neighbor table contains the node 12 information. Therefore, the packet is transmitted to the node 12.

Node 12 extracts the new next address (node 13) from the SRH of the received packet and sends the data packet to node 13 with reference to the neighbor node table. Since node 13 is the final destination address of the data packet, the transmission process of the data packet is terminated.

On the other hand, an embodiment of the present invention may include a computer-readable recording medium including a program for performing the methods described herein on a computer. The computer-readable recording medium may include a program command, a local data file, a local data structure, or the like, alone or in combination. The media may be those specially designed and constructed for the present invention or may be known and available to those of ordinary skill in the computer software arts. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape, optical recording media such as CD-ROMs and DVDs, magneto-optical media such as floppy disks, and magnetic media such as ROMs, And hardware devices specifically configured to store and execute program instructions. Examples of program instructions may include machine language code such as those generated by a compiler, as well as high-level language code that may be executed by a computer using an interpreter or the like.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the present invention. I will understand.

Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined by equivalents to the appended claims, as well as the appended claims.

100: mixed-mode routing node
102: setting unit
104: packet generator
106: packet transceiver
108: DIO message processing unit
110: DAO message processing unit
112: data packet processing unit

Claims (13)

A DIO message processing unit for receiving a DIO message and setting the down routing mode of the routing node or changing the preset down routing mode according to the down routing mode setting information included in the received DIO message and a preset down routing mode change condition. ;
Receive a DAO message, and according to the target prefix of the RPL target option (RPL Target Option) of the received DAO message, the transmission address that transmitted the DAO message and the downlink routing mode of the routing node of the DAO message A DAO message processing unit for changing a parent address of a Transit Information Option or updating a routing table; And
Receiving a data packet, obtaining a next address to transmit the data packet from a source route header (SRH) included in the data packet, and searching for the next node address in a neighbor table or a routing table And a data packet processor for transmitting the data packet according to the RPL routing protocol.
The method according to claim 1,
The DIO message processing unit, when the down-routing mode and mixed mode flag of the received DIO message is set, determines whether the down-routing mode change condition is satisfied, and if it is satisfied to change the preset down-routing mode, Mixed mode routing node.
The method according to claim 2,
The mixed mode flag is obtained from a predetermined bit of an unused flag or a reserved field of the received DIO message.
The method according to claim 1,
The DAO message processing unit, wherein the downlink routing mode of the routing node is a non-storage mode, a target prefix address of an RPL target option of the DAO message, and an address of a transmitting node that has transmitted the DAO message. Matches, enters the address of the routing node in the parent address field of the Transit Information Option of the DAO message and transmits the input DAO message.
The method of claim 4,
The DAO message processing unit, when the target prefix address of the RPL Target Option of the DAO message and the address of the transmitting node that sent the DAO message does not match, Transit Information Option of the DAO message Mixed mode routing node for inputting the address of the DAO transmitting node in the parent address field of the, and transmitting the input DAO message.
The method according to claim 1,
The data packet processing unit transmits the data packet to the next node when the next node address exists in the neighbor table.
Mixed mode routing in which the next node address obtained when not present in the neighbor table is searched in a routing table to obtain routing information corresponding to the next node address, and the data packet is transmitted according to the obtained routing information. Node.
A mixed mode routing method in an RPL routing protocol performed in a mixed mode routing node,
A first step of receiving a DIO message and setting the down routing mode of the routing node or changing the preset down routing mode according to the down routing mode setting information included in the received DIO message and a preset down routing mode change condition; ;
Receive a DAO message, and according to the target prefix of the RPL target option (RPL Target Option) of the received DAO message, the transmission address that transmitted the DAO message and the downlink routing mode of the routing node of the DAO message A second step of changing a parent address of a Transit Information Option or updating a routing table; And
Receiving a data packet, obtaining a next address to transmit the data packet from a source route header (SRH) included in the data packet, and searching for the next node address in a neighbor table or a routing table And a third step of transmitting the data packet to a next node according to the RPL IPv6 routing protocol.
The method of claim 7,
The first step may include: a first-first step of determining whether a downward routing mode of the received DIO message is set and a mixed mode flag is activated;
Determining whether the downlink routing mode change condition is satisfied when the downlink routing mode is set and the mixed mode flag is activated; And
When the downlink routing mode change condition is satisfied as a result of the determination in step 1-2, when the preset downlink routing mode is the storage mode, the mode is changed to a non-storing mode, and the preset downlink routing is performed. If the mode is a non-save mode, mixed mode routing method further comprises steps 1-3.
The method according to claim 8,
The mixed mode flag of the received DIO message is obtained from a predetermined bit among an unused flag or a reserved field of the DIO message.
The method of claim 7,
The second step may include a step 2-1 of determining a downlink routing mode of the routing node;
As a result of the determination in step 2-1, when the downlink routing mode of the routing node is the non-storage mode, a target prefix address of the RPL target option of the DAO message and the DAO message are transmitted. Step 2-2 of determining whether the addresses of the transmitting nodes match;
A second to third step of inputting an address of the routing node in a parent address field of a Transit Information Option of the DAO message when the determination result of the step 2-2 is matched; And
Mixed mode routing method further comprising the step 2-4 of transmitting the DAO message.
The method of claim 10,
Step 2-3 further includes the step of inputting the address of the DAO transmitting node in the parent address field of the Transit Information Option of the DAO message if the determination of step 2-2 does not match. Routing method.
The method of claim 11,
The third step includes: obtaining a next address (next address) to transmit the data packet from the received source route header of the data packet;
Step 3-2 of determining whether the next node address obtained in step 3-1 exists in a neighbor table;
As a result of the determination in step 3-2, if the next node address exists in the neighbor table, the data packet is transmitted to the next node. If the next node address does not exist in the neighbor table, the next node address is transmitted in the routing table. And searching for and obtaining routing information corresponding to the next node address, and transmitting the data packet to a next node according to the obtained routing information.
A computer-readable recording medium having recorded thereon a program for performing the method according to any one of claims 7 to 12 on a computer.

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