KR20050079459A - Secure router and method for routing thereof - Google Patents

Abstract

The present invention relates to a routing method that can establish a path considering safety with a secure path of data. Routing is defined to be updated to a lower security level by comparing the security level that each node can provide in the nodes passing from the source node to the destination node before sending the packet from the source node. Broadcast a Route Request (RREQ) that includes the security level field. When the source node receives a route reply message (RREP) including a hop number indicating the number of passing nodes from the destination node and a security level field indicating a security level of the route, the hop node and the security level field are respectively provided. Configure the routing table based on the route setting criteria. As a result, it is possible to secure the shortest path through the hop number and the secure path through the security level, and to set the appropriate path according to the resource and security requirements of the packet to be transmitted, thereby enabling the data transmission to be more secure and stable.

Description

Secure router and method for routing

The present invention relates to a networking apparatus and a method, and more particularly, to a security router capable of routing with consideration of security as well as a shortest route setting and a routing method thereof.

Routing protocol is used as one of the process of delivering the packet to the destination on the network. Routing is the process of establishing a path to a destination node before sending a packet from one node on the network.

Looking at the routing process in more detail, when a packet is sent from a source node to a destination node, it first broadcasts a Route Request (RREQ) that asks neighbor nodes for a route to the destination. Neighbors that receive an RREQ compare the queried destination address with the addresses registered in their routing table, and if they have a route to the destination address, forward the RREQ to the destination node; otherwise, the neighbor node according to its routing table. Resend to nodes. In response to the transmitted RREQ, the destination node sends a RREP (Route Reply) to the source node in response. When the RREP is received, the source node sets up its routing table with reference to the RREP. Thereafter, the source node transmits the packet to the destination node along the newly set routing table.

In the above routing protocol, the RREP responded from the destination may be transmitted from other neighbor nodes instead of one neighbor node, and from these various paths, the source node establishes the shortest path to the destination. The distance of the path is determined by the hop count of the RREP, which indicates the number of transit routers.

On the other hand, Ad-Hoc network has been proposed as a form of network. Ad-Hoc network is a network that allows mobile hosts to communicate with each other without having a fixed wired network. In an Ad-Hoc network, each mobile node acts as a router, not just a host, and can have multiple paths to other nodes. You can also set the path dynamically. Therefore, in Ad-Hoc network, there is no restriction on the movement of host and there is no need for wired network and base station, so there is an advantage that it can be implemented with fast network configuration and low cost.

In Ad-Hoc networks, data transfer paths are frequently changed due to nodes moving without a central server, and each node establishes a new path each time. That is, when the above-mentioned routing protocol is applied to an ad hoc network, not only the wired network and the network topology are different, but also the resource supply of a node operating wirelessly becomes difficult due to frequent path change of nodes. Can reduce your computing power. Therefore, Ad-hoc network has more difficulty in setting routing path than existing wired network.

There are two main methods of establishing a route in an ad-hoc network. One is to send a RREQ as soon as a node enters the network, receive a route to the destination node, configure the routing table accordingly, and then periodically update the routing table. In this method, a large amount of nodes are initially calculated and overhead is generated, but after the routing table is configured, the routing table can be maintained only by updating and route management for many nodes can be performed. Typically, there is a DSDV (Destination Sequenced Distance Vector) method. The other is to allow the node to set the path only when there are packets to send. In this method, since there is no need to configure a routing table when there is no intention of packet transmission in a node, it wastes resources. If there is a packet to send, the routing table is configured only for one destination and not for all destinations. Therefore, when a packet to be transmitted is generated, a path search takes a long time, resulting in a late data transmission. Typically, there is an AODV (Ad-Hoc On-demand Distance Vector) method.

1 and 2 show the RREQ and RREP message formats of the AODV scheme, respectively, and FIG. 3 shows a routing table configured at the source node of the AODV scheme. In the table, Destination is the destination node for the data that the source node wants to send, Next is the first neighbor node in the path from the source node to the destination node, and Metric is the number of nodes from the source node to the destination node (hop count). ), Sequence Number is a value that is updated every time routing information is sent from the destination node to prevent an infinite loop, and Istall Time is the time the entry was created (used to delete old or outdated entries). , And Stable data are pointers to tables that contain information about how secure the path is.

In a network, a packet is not only able to reach its destination quickly but also needs to be reached more safely. In general wired environment, the emphasis is on user authentication at the application level rather than terminal authentication. However, Ad-Hoc network basically assumes wireless mobile environment, so the number of nodes entering new network and the number of nodes connecting to new network increases more than existing wired node. There is a problem. That is, in the Ad-Hoc network, there is a need for authentication at each terminal because nodes move. In addition, since there is no central server in the Ad-Hoc network, there is no trust party to verify the identity of the node in the middle.

As mentioned above, various kinds of secure routing protocols have been proposed to compensate for the vulnerability of security due to the movement of nodes in the Ad-Hoc network. One such secure routing method is the Secure-Aware Ad-Hoc Routing for Wireless Network, Seung Yi, Prasad Naldurg. SAR is a protocol based on the AODV scheme mentioned above. The SAR defines what is called a trust level, like a real-world class system, where a place such as an army in the real world is clearly defined, so that once a level at the source node cannot be changed in the middle. Each node is given a trust level, and the processing authority for the packet varies according to the determined level. The originating node sends to the intermediate node an RQ_SEC_REQUIREMENT that records the security level of the route that the originating node wants to find in the real world hierarchy in the RREQ to find the route. Also included in RREQ is RQ_SEC_GUARANTEE, which indicates the maximum level of security the route can provide. When the intermediate node receives the RREQ, the protocol checks if the intermediate node satisfies the security level. If the intermediate node satisfies RQ_SEC_REQUIREMENT, it sends the value to RQ_SEC_GUARANTEE to the next node. At this time, when the intermediate node does not satisfy the confidence level determined by the source node, the RREQ message is dropped and not forwarded. If the packet is forwarded to the next node, the security level is updated. The destination node responds to the source node by copying the value of RQ_SEC_GUARANTEE to RP_SEC_GUARANTEE. The source node receiving the RP_SEC_GUARANTEE sends a packet by configuring a routing table of a path having the minimum number of hops among the responses.

The above SAR is difficult to apply to a wide range of general networks because it only targets special networks that have a clear level in the real world, not the general case. In other words, if an intermediate node does not satisfy the security requirements of the source node, it is dropped on the spot, and no further route search is performed. Therefore, if neighboring nodes have only nodes whose security level is not appropriate, the node may reach the destination. There is a problem that can not set the path. In addition, since the SAR finds a path having a minimum number of hops among the paths satisfying the security level, it is difficult to search the path when the network is not an ideal network.

An object of the present invention is to provide a security router and its routing method that can secure the data transmission path more stably while considering security by applying the minimum number of hops and the security level flexibly to solve the above problems. .

The router of the present invention for achieving the above object has an interface for exchanging messages with external nodes, and a set security level, and each node in the nodes passing through the set security level and the destination node when a packet to be transmitted is generated. And a control unit for broadcasting a route request message (RREQ) including a security level field defined to be updated to a lower security level by comparing the security level that can be provided through the interface.

The router may further include an internal interface for exchanging messages with internal nodes.

The control unit compares the security level written in the security level field of the RREQ with the set security level and updates the lower security level in the security level field when receiving the RREQ in which the security level is written. If the RREQ is repeatedly received through another path, the hop number indicating the number of transit nodes and the security level written in the security level field are compared with the hop number and security level of the RREQ received through another path. If it is determined to be low, drop it.

When the control unit receives an RREQ destined for itself, the control unit compares the security level included in the RREQ with the security level set to itself, and includes a route response message including a security level field defined to be updated to a lower security level. Route Reply: RREP) is transmitted through the interface.

When the RREP is received in response to the transmitted RREQ, the controller configures a routing table based on the hop number and security level written in the RREP.

The routing table may consist of a path having a minimum number of hops and a path having a maximum security level among responded RREPs, and may alternatively include multiple paths according to the answered RREPs. In the routing table including multiple paths, paths having a security level up to a predetermined rank among the replied RREPs may be configured.

The controller sets a path based on a security level in the routing table for a packet that requires a predetermined level or more in a state where there are many resources, and sets a path based on a security level in the state where there are few resources. Set the path based on the hop count. In this case, the controller may variably apply the routing criteria according to the resource and the security request.

According to another aspect of the present invention, there is provided a security routing method comprising: determining whether a packet to be transmitted is generated; and if it is determined that the packet to be transmitted is generated at the determination step, each node at nodes passing through the set security level and the destination node. Comparing the security level that can be provided by the step of broadcasting a Route Request message (RREQ) including a security level field defined to be updated to a lower security level.

The security routing method may include checking a destination of the RREQ when a RREQ having a security level written therein is received; and if the destination address of the RREQ does not match an address assigned to the RREQ, the set security level and the security level of the RREQ. Comparing the security level written in the field, updating the lower security level to the security level field in the comparing step, and forwarding the RREQ with the updated security level field.

The secure routing method includes a hop number indicating the number of transit nodes and a security level written in the security level field when the RREQ is repeatedly received through another path whose destination address does not match the address assigned to it. Comparing the hop count and security level of the RREQ received through another path, and the hop count and security level of the RREQ repeatedly received in the comparing step are both lower than the hop count and security level of the previously received RREQ. And if it is determined, dropping.

The secure routing method may further include: determining whether a RREQ is received as a destination; and when the destination address of the received RREQ is determined to be the same address as the address assigned to the RREQ, the security level included in the RREQ; The method further includes responding to a source node of the RREQ with a route reply message (RREP) including a security level field defined to compare the security level set to the self and be updated to a lower security level.

The secure routing method may further include determining whether the RREP is received in response to the transmitted RREQ, and if the RREP is received in response to the RREQ transmitted in the determining step, the hop written in the RREP. The method may further include configuring a routing table based on the number and the security level, respectively.

The secure router and its routing method as described above can not only search the shortest path for data transmission, but also check the security level provided by the paths, thereby establishing a more secure path while securing a more stable path.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

4 is a schematic block diagram of a router according to an embodiment of the present invention. The router includes a controller 120 having an interface 110 and a routing table 122.

The interface 110 exchanges messages with external nodes (EN). In addition, the interface 110 may exchange messages with internal nodes (not shown) when an internal network centered on a router exists.

The controller 120 has a set security level, and when a packet to be transmitted is generated, the controller 120 is defined to be updated to a lower security level by comparing the set security level with the security level that each node can provide from nodes passing through to the destination node. The route request message (RREQ) including the secure level field is broadcasted to the external nodes EN1 to EN3 through the interface 110.

5 is a diagram illustrating a RREQ message format according to an embodiment of the present invention. The RREQ message format further includes a security level field for writing a security level in the conventional AODV scheme RREQ shown in FIG. 1.

In addition, when receiving a RREQ having a security level written as a destination that does not set itself as the destination, the controller 120 compares the security level set to the security level written in the security level field of the RREQ with the lower security level to the security level field. Update and forward.

In addition, the control unit 120, when receiving the RREQ as a destination, the route response message including a security level field defined to compare the security level set in the RREQ with the security level set to itself and update to a lower security level (Route Reply: RREP) is transmitted through the interface 110. 6 illustrates an RREP message format according to an embodiment of the present invention.

In addition, when the RREP is received in response to the transmitted RREQ, the controller 120 configures a routing table based on the hop number and security level written in the RREP.

7 is a diagram illustrating a routing table according to an embodiment of the present invention. The routing table includes a security level as a field along with a metric indicating the number of hops to be the routing criteria to the destination node. That is, when a route table stores a route for one destination in the route table, the routing table stores information about a route that is more distant but more secure, as well as the minimum number of hops. Only the path having the maximum security level may be stored for the path that guarantees safety, or alternatively, only the security path up to a predetermined rank may be stored. It can also be stored only for paths that are above a certain security level.

8 is a network diagram illustrating a security routing method according to the present invention. Each node has a set security level that it can support. The security level set at each node (A ~ E) can be changed flexibly according to the resource situation such as node's computing power, resource, storage capacity, bandwidth of the network to which it belongs, and the changed security level is reflected through routing update. When a packet is transmitted from node A to node E in a network composed of such nodes A through E, node A broadcasts an RREQ including a security level field to request the network for routing information for the destination node E. Cast. The intermediate nodes (B, C, D) check the security level field included in the RREQ, compare it with their own security level, and update the smaller security level field before forwarding the RREQ from node A. do. When receiving the RREQ, the destination node E compares the security level of the RREQ with its own security level like the intermediate node and writes a lower security level into the security level field.

FIG. 9 illustrates RREQ reaching node E along path A of FIG. 8. The security level field of the RREQ contains the security level '3' from the comparison of node A's security level '5' and node B's security level '3', and updated security level '3' and The security level '3' was determined and written from the comparison result of the security level '4'. In addition, the hop number in Path A is '2'. The security level field is the maximum security level that can be commonly provided in the path A when the destination node E is reached.

The destination node E responds to the originating node A by writing the security level determined from the route through which the RREQ is delivered to the security level feed of the RREP.

FIG. 10 illustrates an RREP sent in response to an RREQ along Path B of FIG. 8. The security level determined in Path B is '4' and the hop count is '3'. On the other hand, the source node A constructs a routing table from the RREPs of the A path and the B path.

FIG. 11 is a diagram illustrating a routing table configured with nodes E, C, and D as destinations in node A, respectively. It can be seen that the path through node B for the destination node E is registered with the number of hops '2' and the security level '3', which represents the path A in FIG. 8. In addition, it can be seen that the path through node C for the same destination node E is registered with a hop number of '3' and a security level of '4', and represents path B of FIG. 8. In addition, the number of hops along the route and the security level of the node C and the node D, respectively, are also displayed.

In the above, it can be seen that the source node uses two criteria when sending a packet. One is the minimum number of hops representing the shortest path, as used in the general routing protocol, and the other is the level of security provided by the cooperation of each node on the path. By recording the minimum hop count and hop count, but with a high security level in the routing table, the source node can flexibly determine the path when sending packets. In other words, if a node has a lot of resources and needs security, it can be sent in a path that guarantees a high level of security, and provides the fastest path for a packet that lacks available resources or does not require special security. Data can be transferred over the smallest hop count, providing flexibility, stability and safety.

According to the security router and the routing method of the present invention as described above, rather than simply finding a path for fast data transmission, the security level provided by the path can be taken into consideration so that data can be transmitted more safely and more stably. The transmission path can be secured.

In addition, since the node authentication is performed while updating in one direction in setting the path from the source node to the destination node, it is possible to search the path efficiently without requiring a large amount of calculation and storage capacity.

1 and 2 are RREQ and RREP message formats of the AODV scheme, respectively.

3 is a routing table configured in an AODV source node;

4 is a schematic block diagram of a router according to an embodiment of the present invention.

5 is an RREQ message format according to an embodiment of the present invention;

6 is an RREP message format according to an embodiment of the present invention;

7 is a routing table according to an embodiment of the present invention;

8 is a diagram illustrating a network for explaining security routing according to the present invention;

FIG. 9 is an RREQ format reaching node E along path A of FIG. 8;

FIG. 10 is an RREP format sent in response to an RREQ along Path B of FIG. 8, and

11 is a routing table configured with nodes A, C, and D as destinations in node A, respectively.

Claims (21)

An interface for exchanging messages with external nodes; And A security level field that has a set security level and is defined to be updated to a lower security level by comparing the security level that each node can provide in the nodes passing through the set security level and the destination node when a packet to be transmitted is generated. And a controller for broadcasting a route request message (RREQ) through the interface. The method of claim 1, And an internal interface for exchanging messages with internal nodes. The method of claim 1, The control unit compares the security level written in the security level field of the RREQ with the set security level and updates the lower security level in the security level field when receiving the RREQ in which the security level is written. Secure router, characterized in that. The method of claim 3, wherein If the RREQ is repeatedly received through another path, the controller may include hop counts indicating the number of transit nodes and the security level written in the security level field, and the hop count and security level of the RREQ received through another path. The security router, characterized in that to drop if compared to all low. The method of claim 1, When the control unit receives an RREQ destined for itself, the control unit compares the security level included in the RREQ with the security level set to itself, and includes a route response message including a security level field defined to be updated to a lower security level. Route Reply (RREP) is transmitted over the interface. The method of claim 5, And the controller configures a routing table based on the hop number and security level written in the RREP when the RREP is received in response to the transmitted RREQ. The method of claim 6, The routing table comprises a route having a minimum hop count and a route having a maximum security level among the replied RREPs. The method of claim 6, The routing table comprises multiple paths according to the answered RREPs. The method of claim 8, The routing table comprises a route having a security level up to a predetermined rank among the answered RREPs. The method of claim 6, The controller sets a path based on a security level in the routing table for a packet that requires a predetermined level or more in a state where there are many resources, and sets a path based on a security level in the state where there are few resources. A secure router, characterized in that it establishes a route based on the number of hops. The method of claim 10, And the controller variably applies the routing criteria according to the resource and the security request. Determining whether a packet to be transmitted has occurred; And If it is determined in the determining step that a packet to be transmitted is generated, a security level field defined to be updated to a lower security level is compared by comparing the security level that each node can provide in the nodes passing through the set security level and the destination node. Broadcasting a route request message (RuteQ) including a; routing method for a secure router comprising a. The method of claim 12, Checking a destination of the RREQ when an RREQ having a security level written thereto is received; Comparing the set security level with the security level written in the security level field of the RREQ if the destination address of the RREQ does not match the address assigned to the RREQ; Updating a lower security level in the security level field in the comparing step; And And forwarding the RREQ having the updated security level field. The method of claim 13, If the RREQ is repeatedly received through another route whose destination address does not match the address assigned to it, the hop number indicating the number of transit nodes and the security level written in the security level field are received through the other route. Comparing the hop count and security level of one RREQ; And And if it is determined that the hop number and security level of the RREQ repeatedly received in the comparing step are lower than both the hop number and security level of the previously received RREQ, the method further comprises: dropping the RREQ. Routing method. The method of claim 12, Determining whether a RREQ has been received as a destination; And If the destination address of the received RREQ is determined to be the same address assigned to it, a security level field defined to compare the security level included in the RREQ with the security level set to the user and be updated to a lower security level is provided. And responding to an originating node of the RREQ with a route reply message (RREP). The method of claim 15, Determining whether to receive the RREP in response to the transmitted RREQ; And And if it is determined that the RREP has been received in response to the RREQ transmitted in the determining step, constructing a routing table based on each hop number and security level written in the RREP. Routing method. The method of claim 16, The routing table comprises a path having a minimum hop number and a path having a maximum security level among the answered RREPs. The method of claim 16, The routing table comprises multiple paths according to the answered RREPs. The method of claim 18, And the routing table comprises a path having a security level up to a predetermined rank among the answered RREPs. The method of claim 16, The packet transmission path setting through the routing table sets a path based on the security level in the routing table for packets that require more than a predetermined level of security in a resource-rich state. Routing method for a security router, characterized in that for the packet requesting a route based on the number of hops. The method of claim 20, The method of routing a packet through the routing table may be configured to variably apply the routing criteria according to the resource and the security request.