KR100997336B1 - Apparatus and method for managing link information of OSPF protocol on overlay network - Google Patents

Abstract

The present invention relates to an apparatus and method for managing link information of an Open Shortest Path First (OSPF) protocol on an overlay network.

According to the present invention, the quality of the overlay network is optimized by using the packet delay time between adjacent nodes measured in real time on the overlay network as inter-link distance information of the OSPF protocol.

Description

Apparatus and method for managing link information of OSPF protocol on overlay network}

The present invention relates to an apparatus and method for managing link information of an Open Shortest Path First (OSPF) protocol on an overlay network. More particularly, the present invention relates to packet delay time between adjacent nodes measured in real time on an overlay network. An apparatus and method for managing link information of an OSPF protocol for optimizing the quality of an overlay network by using it as link-to-link distance information of a protocol.

An overlay network is a virtual network formed by forming logical links between separate nodes on an existing physical network. Herein, a separate node selected from existing physical nodes is called an overlay node, and a logical link formed between the overlay nodes is also called a tunnel.

FIG. 1 illustrates the concept of such an overlay network, where a logical link (indicated by a dotted line in FIG. 1) is formed by creating a tunnel between overlay nodes on the overlay network, and the logical link includes several physical links (FIG. 1). By actually connecting through 1 (indicated by a solid line), the two overlay nodes have the effect of being directly connected.

On the other hand, the OSPF (Open Shortest Path First) protocol combines link state information and inter-node distance information in real time to select the shortest path through which packets (or datagrams) are transmitted on the network. Is a dynamic routing protocol that supports routing with the shortest path. For reference, the routing protocol is an internal gateway protocol for performing routing in an autonomous system (AS) and an external routing protocol for performing routing between autonomous systems. Gateway Protocol (OSP) can be classified as a representative internal routing protocol along with Routing Information Protocol (RIP).

The OSPF protocol transmits link information including link state information and inter-node distance information to neighboring nodes periodically or when the link state changes, and thus exchanges link information with neighboring nodes. Calculate the shortest path by finding out. At this time, the distance information between nodes constituting the link information is the basis for calculating the shortest path (ie, routing information), and thus is an important factor for determining the quality of the entire network.

In this regard, in the related art, the distance between nodes generally uses a bandwidth between nodes, and the shortest path is obtained by obtaining a distance cost for each section using the bandwidth (unit: bps). Calculate

However, in the case of the overlay network, since the link between the overlay nodes is a logical link formed through a plurality of physical nodes, there is a problem in that it is difficult to accurately determine the bandwidth between nodes as distance information between nodes as in the prior art. In other words, there is a problem in that the bandwidth measured for each physical link cannot be applied by simply summing or averaging for a logical link including several physical links.

The present invention was devised to solve the above problems, and an object of the present invention is to use the quality of the overlay network in real time by using the packet delay time between adjacent nodes measured in real time on the overlay network as the inter-link distance information of the OSPF protocol. The present invention provides an apparatus and method for managing link information of an OSPF protocol, which is optimized according to traffic conditions.

Another object of the present invention is an apparatus and method for managing link information of an OSPF protocol which can obtain optimal results by reflecting changes in traffic in real time by periodically updating link information by measuring packet delay time between adjacent nodes on an overlay network. To provide.

Another object of the present invention is to update link information only when the rate of increase or decrease of packet delay time between adjacent nodes exceeds a predetermined threshold, thereby efficiently controlling the load that may occur due to frequent changes in traffic conditions. It is to provide an apparatus and method for managing link information.

For the above purpose, an apparatus for managing link information of an Open Shortest Path First (OSPF) protocol on an overlay network of one embodiment of the present invention is provided with respect to an adjacent node participating in routing information exchange of the OSPF protocol. A neighbor node information management unit managing information; A delay time measuring unit configured to measure a packet delay time by transmitting and receiving a packet with respect to the adjacent node; And a link information manager for managing link information for the neighbor node, wherein the link information manager uses a packet delay time for the neighbor node as inter-node distance information included in the link information.

In addition, a router using an Open Shortest Path First (OSPF) protocol on an overlay network of one embodiment of the present invention has a packet delay time for an adjacent node participating in the exchange of routing information of the OSPF protocol. A link information management device using the measured packet delay time as inter-node distance information constituting link information for the adjacent node; And an OSPF routing processor configured to calculate a shortest path to the adjacent node using the link information and to route a packet using routing information generated based on the shortest path.

In addition, a method of managing link information of an Open Shortest Path First (OSPF) protocol on an overlay network of one embodiment of the present invention includes: a) echoing to an adjacent node participating in the exchange of routing information of the OSPF protocol; Echo) transmitting a packet; b) receiving an echo reply packet corresponding to the echo packet from the neighbor node; c) calculating a packet delay time for the adjacent node using the transmission time of the echo packet and the reception time of the echo response packet; And d) using the packet delay time for the neighbor node as link information for the neighbor node.

According to the present invention, by using the packet delay time between adjacent nodes on the overlay network as the inter-node distance information of the OSPF protocol, the shortest path to the destination can be obtained.

In addition, according to the present invention, by periodically measuring the packet delay time between adjacent nodes on the overlay network and reflecting it, it is possible to optimize the quality of the network in consideration of the traffic amount in real time.

In addition, according to the present invention, by updating the link information only when the rate of increase or decrease of the packet delay time between adjacent nodes exceeds a predetermined threshold value, it is possible to efficiently control the load that may occur due to frequent changes in traffic conditions. Has

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments. For reference, in the following description, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention are omitted.

 In addition, in the following description, link information management for adjacent nodes (eg, node b, node c, node d) is described in terms of a link information management device (or router) located at a reference node (eg, node a). Describe.

First, FIG. 2 is a diagram illustrating a configuration of a link information management apparatus 110 of an OSPF protocol according to an embodiment of the present invention. 3 is a diagram illustrating a configuration of the router 100 including the link information management apparatus 110 of FIG. 2.

As shown in FIG. 2, the link information management apparatus 110 according to the present invention includes an adjacent node information management unit 112, a delay time measuring unit 114, a link information management unit 116, and a link information setting unit 118. And the like.

The neighbor node information manager 112 manages information of neighbor nodes (which are overlay nodes) connected by a link participating in routing information exchange of the OSPF protocol on the overlay network. In this case, the neighbor node information manager 112 may store and manage the information and the state of the neighbor node in the form of an OSPF neighbor table. For reference, the OSPF neighbor table may include information such as a neighbor node identifier (ID), a node state, a dead time, a node address, an interface, and the like.

The delay time measuring unit 114 transmits a packet to neighboring nodes based on the information provided by the neighboring node information management unit 112 (information about neighboring nodes) and measures the time at which a response comes to the packet for the corresponding neighboring node. Measure the delay time.

FIG. 4 is a diagram illustrating the method of measuring a packet delay time for an adjacent node according to the present invention. For reference, in FIG. 4, node a is assumed as a reference, and neighboring nodes thereof are assumed to be node b, node c, and node d.

Referring to FIG. 4, the delay time measuring unit 114 transmits a first echo packet to the neighbor node c at 0.0 ms, and transmits a second echo packet to the neighbor node b at 0.5 ms. Then, the neighbor node c receiving the first echo packet transmits a first echo reply packet to the node a in response thereto, and similarly, the neighbor node b receiving the second echo packet responds to the request. 2 Sends an echo response packet to node a. If the first echo response packet arrives at node a at 1.2 ms and the second echo response packet arrives at node a at 2.1 ms, the delay time measuring unit 114 echoes the echo packet transmission time and echo to the corresponding node. Packet delay time is measured using the response packet reception time. That is, the delay time measuring unit 114 measures 1.6 ms (= 2.1 ms-0.5 ms) as the packet delay time for the neighbor node b, and packet packets 1.2 ms (= 1.2 ms-0.0 ms) for the neighbor node c. Measure with delay time.

The link information manager 116 manages link information between neighbor nodes based on the information transmitted from the neighbor node information manager 112 and the delay time measurer 114. Specifically, the link information management unit 116 stores and manages link state information, distance information between nodes, and the like for a corresponding link (which is a logical link) in the form of a link information table illustrated in FIG. 4, for example. . In this case, the present invention uses the packet delay time measured by the above-described delay time measuring unit 114 as the inter-node distance information. Alternatively, an estimated bandwidth may be used based on the packet delay time, which may be estimated by dividing the packet size used for transmission by the packet delay time, for example. For reference, in this case, the estimated bandwidth of the present invention is different from the bandwidth measured between existing physical links, i.e., the estimated bandwidth of the present invention is measured for several physical links constituting it for the logical link on the overlay network. It is estimated using packet delay time between adjacent nodes rather than using bandwidth.

On the other hand, the link information manager 116 may update the distance information between the nodes of the link information table whenever the delay time measuring unit 114 measures the packet delay time (preferably periodically). As an example, the link information table may be updated only when the new packet delay time or the bandwidth estimated based thereon is compared with the previously stored information and the increase / decrease rate exceeds a specified threshold (limit value). Then, the link information management unit 116 notifies the link information setting unit 118 of the update of the link information table.

Then, the link information setting unit 118 transmits the link information provided by the link information management unit 116 to the OSPF routing processor 120.

Referring back to FIG. 3, the OSPF routing processor 120 includes a shortest path calculator 122, a routing information manager 124, a routing processor 126, and the like.

The shortest path calculator 122 calculates the shortest path for transmitting the received packet to the corresponding destination by using the link information (link state information, distance between nodes, etc.) transmitted from the link information setting unit 118. do.

The routing information manager 124 stores and manages routing information generated based on the shortest path calculated by the shortest path calculator 122 in the form of a routing table.

Then, the routing processor 126 routes the packet received from the outside (for example, the neighbor node b) to the neighbor node (for example, the neighbor node c) corresponding to the shortest path to the destination by using the generated routing information. .

On the other hand, the operation performed in the inside based on a predetermined router so far has been described. For reference, in the case of the OSPF protocol, if there is a change in link information, the link state advertisement (LSA) is synchronized to synchronize it with all routers in the area. In order to reduce the load on the network, the router informs the designated router (DR) of the changed link information and the designated router transmits the LSA packet to all routers in the region.

Hereinafter, the link information management method of the OSPF protocol according to the present invention will be described with reference to FIGS. 5 and 6. For reference, a detailed process or operation principle of the link information management method of the OSPF protocol according to the present invention may refer to the description of the link information management apparatus of the OSPF protocol described above. do.

5 is a flowchart illustrating a link information management method of an OSPF protocol according to an embodiment of the present invention.

First, in step S510, the link information management apparatus transmits an echo message to an adjacent node (or router) for distance measurement between nodes and stores the transmission time. Then, the neighbor node receiving the echo packet transmits an echo reply packet to the link information management apparatus. In step S520, the link information management apparatus receives the echo response packet from the neighbor node and stores the reception time. .

In operation S530, the link information management apparatus calculates a packet delay time for the corresponding neighbor node using the echo packet transmission time and the echo response packet reception time. The link information management apparatus then uses the packet delay time measured as the inter-node distance information of the link information. Alternatively, the estimated bandwidth may be used instead of the packet delay time as the inter-node distance information.

In step S540, the routing processor calculates the shortest path based on the link information (link state information, inter-node distance information, etc.) transmitted from the link information management apparatus. In this case, as the inter-node distance information for calculating the shortest path, the aforementioned packet delay time or the bandwidth estimated based thereon may be used. The routing processor generates routing information based on the shortest path calculated in this way.

Finally, in step S550, the routing processor uses the routing information to route the packet received from the outside to the adjacent node corresponding to the shortest path to the destination.

6 is a flowchart illustrating a link information management method of an OSPF protocol according to another embodiment of the present invention.

First, in step S610, the link information management apparatus transmits an echo message to an adjacent node (or router) for distance measurement between nodes and stores the transmission time. Then, the neighbor node receiving the echo packet transmits an echo reply packet to the link information management apparatus. In step S620, the link information management apparatus receives the echo response packet from the neighbor node and stores the reception time. .

In step S630, the link information management apparatus calculates a packet delay time for the corresponding neighbor node using the echo packet transmission time and the echo response packet reception time. In operation S640, the link information management apparatus estimates a bandwidth of the corresponding link using the packet delay time.

In step S650, the link information management apparatus compares the estimated bandwidth with the previous bandwidth stored in the link information table, calculates the increase / decrease rate, and determines whether the bandwidth increase / decrease rate exceeds a preset threshold (limit value). To judge. For reference, the threshold value may be set by dividing the upper limit threshold value and the lower limit threshold value.

As a result of the determination in step S650, if the bandwidth increase / decrease rate exceeds a preset threshold, in step S660, the link information management apparatus updates the link information by storing the newly estimated bandwidth in the link information table.

Then, in step S670, the routing processor calculates the shortest path based on the updated link information (link state information, distance information between nodes, etc.) transmitted from the link information management device. In this case, as the inter-node distance information for calculating the shortest path, the aforementioned packet delay time or the bandwidth estimated based thereon may be used. The routing processor generates routing information based on the shortest path calculated in this way.

On the other hand, if it is determined in step S650 that the bandwidth increase / decrease rate does not exceed a preset threshold, the link information management apparatus uses previously stored link information (ie, inter-node distance information) without updating the link information table. In this case, since the shortest path is already calculated based on the previously stored link information, the shortest path calculation process (step S670) is omitted.

Finally, in step S680, the routing processor uses the routing information to route the packet received from the outside to the adjacent node corresponding to the shortest path to the destination.

Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art to which the present invention pertains may implement the above-described embodiments without changing the technical spirit or essential features of the present invention. The examples are to be understood in all respects as illustrative and not restrictive.

In addition, the scope of the present invention is specified by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention. Should be interpreted as

1 is a diagram illustrating the concept of an overlay network.

2 is a block diagram of an apparatus for managing link information of an OSPF protocol according to an embodiment of the present invention.

3 is a block diagram of a router including an apparatus for managing link information of an OSPF protocol according to an embodiment of the present invention.

4 is a diagram illustrating a method of measuring packet delay time for an adjacent node according to the present invention.

5 is a flowchart illustrating a link information management method of an OSPF protocol according to an embodiment of the present invention.

6 is a flowchart illustrating a link information management method of an OSPF protocol according to another embodiment of the present invention.

Claims (14)

A device for managing link information of an Open Shortest Path First (OSPF) protocol on an overlay network, A neighbor node information manager configured to manage information on neighbor overlay nodes participating in routing information exchange of the OSPF protocol; Transmitting an echo packet to the neighbor overlay node, receiving an echo reply packet corresponding to the echo packet from the neighbor overlay node, transmitting time of the echo packet and receiving time of the echo response packet Delay time measuring unit for measuring the packet delay time using; A link information management unit managing link information of the OSPF protocol with respect to the adjacent overlay node; And It includes a link information setting unit for transmitting the link information of the OSPF protocol to the OSPF routing processor, The link information management unit uses the packet delay time for the adjacent overlay node as distance information between nodes constituting link information of the OSPF protocol. delete delete The method of claim 1, And the delay time measuring unit measures a packet delay time for the neighboring overlay node periodically or when there is a state change of the neighboring overlay node. The method of claim 4, wherein And the link information management unit updates the link information of the OSPF protocol when the measured increase / decrease rate of the packet delay time exceeds a preset threshold. The method of claim 4, wherein And the link information management unit updates the link information of the OSPF protocol when a rate of increase or decrease of the bandwidth estimated based on the measured packet delay time exceeds a preset threshold. As a router using the Open Shortest Path First (OSPF) protocol on an Overlay Network, Transmit echo packets to neighboring overlay nodes participating in the exchange of routing information of the OSPF protocol, receive echo reply packets corresponding to the echo packets from neighbor overlay nodes, and transmit echo packets A link information management apparatus for measuring a packet delay time using a time and a reception time of the echo response packet and using the measured packet delay time as inter-node distance information constituting link information of the OSPF protocol; And And an OSPF routing processor that calculates the shortest path to the adjacent overlay node using the link information of the OSPF protocol and routes the packet using the routing information generated based on the shortest path. The method of claim 7, wherein Wherein the shortest path is calculated using an estimated bandwidth based on a packet delay time for the adjacent overlay node. The method of claim 7, wherein And the link information management device updates link information of the OSPF protocol for the neighboring overlay node when the measured increase / decrease rate of the packet delay time exceeds a preset threshold. As a method of managing link information of an Open Shortest Path First (OSPF) protocol on an overlay network, a) transmitting an Echo packet to an adjacent overlay node participating in the routing information exchange of the OSPF protocol; b) receiving an echo reply packet corresponding to the echo packet from the neighbor overlay node; c) calculating a packet delay time for the adjacent overlay node using the transmission time of the echo packet and the reception time of the echo response packet; And d) using the packet delay time for the adjacent overlay node as inter-node distance information constituting link information of the OSPF protocol. delete The method of claim 10, In step d), And estimating a bandwidth based on a packet delay time for the adjacent overlay node, and using the estimated bandwidth as inter-node distance information constituting link information of the OSPF protocol. The method of claim 12, The bandwidth is estimated by dividing the size of the packet transmitted and received with respect to the neighbor overlay node by the packet delay time. The method of claim 12, and d ') updating link information of the OSPF protocol when the estimated increase / decrease rate of the bandwidth exceeds a preset threshold.

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