KR100538357B1 - Apparatus for supplying path of asynchronous transfer network and method therefor - Google Patents

Abstract

The present invention relates to an apparatus and a method for providing a path of an asynchronous transmission network, and more particularly, to an apparatus and a method for providing an path of an asynchronous transmission network to provide an optimal path for establishing an asynchronous transmission mode connection of a high speed communication network. The present invention reads only the node identifiers of both ends of the node and the link from the database that manages the detailed information of the network for initial path selection, converts them into a form suitable for path finding, and stores them in a memory, and requests the optimal path from the operator. Wait After all the possible paths are found by the operator on the basis of the optimal path from the operator, the unusable paths are removed one by one by referring to the database that maintains the detailed information of the actual network and sorted by the number of nodes via the remaining paths. By providing the operator with not only the optimal path, but also the possible paths found in the path search process, the operator can be selected so that the path appropriate for the operation policy can be selected. Therefore, the present invention does not maintain the detailed information of the actual network because all the paths are searched node by node in order to search for the optimal path, and does not require an additional operation for matching them with the actual network state. In addition, when the automatic management network management system is inoperable, it is easy to switch the manual operation by the operator.

Description

Apparatus for supplying path of asynchronous transfer network and method therefor}

The present invention relates to an apparatus and a method for providing a path of an asynchronous transmission network, and more particularly, to provide N possible paths and optimal paths for connection establishment in an asynchronous transmission mode of a high speed communication network. The present invention relates to a technique for searching for an optimal path through a path search in a sub network configured in the entire network and a path search between sub networks without targeting all nodes constituting the network.

FIG. 1 illustrates a structure of a conventional high speed communication network, in which asynchronous transmission mode exchangers 1 to 5 in a close area are divided to manage a large scale high speed communication network into a plurality of sub networks 20 and 30. It consists of a sub-network 20 of one logical form. Each of the subnetworks 20 and 30 is composed of asynchronous transmission mode exchangers 1 to 10 and identifiers connected to the physical trunk and the logical trunk 2. The trunk 2 serves to transmit data of the exchange to other exchanges. The trunk 2 divides a physical trunk into several logical trunks according to a hierarchical management concept of an asynchronous transmission mode network. Here, the logical trunk may be created and deleted more variably than the physical trunk. In addition, the maximum allowable bandwidth, the number of acceptable connections, and the occurrence of a failure are maintained as attributes of physical trunks and logical trunks. In addition, the priority of the allocation of the trunk is determined as well as whether or not the trunk is allocated in comparison with the user's requested bandwidth provided in the connection request.

In the conventional communication network having such a configuration, the selection of the shortest path is a necessary process for providing smooth service as well as efficient use of network resources. There are two methods for selecting an optimal route. There are two methods of constructing a routing table in advance and a least expensive route through cost calculation.

First, a method of constructing a routing table is a method of sequentially searching for a node identifier at a given starting point and a node identifier at a given starting point when requesting a route between two specific points while maintaining a list of possible routes between all nodes in a communication network. Search through to find the best route. However, since this method obtains all possible paths in advance among all nodes, as the number of nodes increases or the upper limit of the number of path nodes increases, the size of the routing table and its search time increase exponentially. In addition, since the routing table is established in advance based on a specific time point, it is difficult to immediately reflect the state of the network that changes with time.

On the other hand, the path selection method for calculating the minimum cost calculates the cost of transferring data starting from the node designated by the operator to all neighboring nodes in consideration of the current network state, and then selects the node and link, which is the minimum cost. Select and recalculate the cost to the selected node, taking into account the least cost node found so far. The path selection method that calculates the minimum cost is a centralized form where one system manages both the shape and state information for the entire network. However, such a method should be reflected in the calculation of the cost value while maintaining the state of the node and the current alarm state and management state of the trunk. There is a problem in that the cost must be increased or decreased if the connection establishment and deletion is successful.

The present invention has been created to solve the above problems, and by searching for a path by dividing the entire network and the sub-network, it does not maintain the state of the node, the state of the trunk and attribute values for the optimal path selection in the entire network. However, the purpose is to enable the path selection according to the operator's operation policy by providing N possible paths as well as the optimal paths in the entire network using the paths found in the sub-networks.

The apparatus for providing a path of an asynchronous transmission network according to the present invention for achieving the above object includes a plurality of nodes searching for an optimal path for each node and selecting an optimal link when requesting a path to a corresponding subnetwork, and transmitting possible paths within the subnetwork. In accordance with the path request from the sub-network path searching device and the operator, all paths of the sub-network units are searched, and a path is requested to the corresponding sub-network path searching device among the plurality of sub-network path searching devices, and received from the corresponding sub-network path searching device. It is characterized in that it comprises a whole network path search apparatus for displaying the optimal path in the entire network by combining the possible paths for each sub-network.

In addition, the path providing method of the asynchronous transmission network of the present invention, the first step of searching for all the paths of the sub-network unit in response to a path request from the operator to request the available path for each sub-network to the corresponding sub-network path search apparatus, and for each sub-network According to the request of the possible paths, the second step of searching for all the paths in the node unit to select the optimal link, and transmitting the possible paths in the sub-network and combining the possible paths in the received sub-network to indicate the optimal path in the entire network It is characterized by having a third step.

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

2 is a block diagram of a path providing apparatus of an asynchronous transmission network according to the present invention.

The present invention is largely composed of a whole network path searching apparatus 100 and a sub network path searching apparatus 200.

Here, the whole network path searching apparatus 100 includes a whole network event receiving unit 110, a whole network path searching requesting unit 120, a whole network path searching unit 130, a whole network link selecting unit 140, And a whole network database 150, a subnetwork capable path processing unit 160, a path combining unit 170 and an operator constraint applying unit 180, and a sub network identifier and both ends of a link connecting them. Maintains identifiers and node identifiers.

In addition, the sub-network path search apparatus 200 may include a sub-network event receiver 210, a sub-network path search requester 220, a sub-network path searcher 230, a sub-network link selector 240, Sub-network database 250, and includes a node identifier and the node identifier at both ends of the link connecting them.

First, the whole network event receiver 110 receives a command from an operator, such as adding or deleting a node and a link that change the network shape. The whole network path search request unit 120 receives a path search request signal from the operator. When the path search request signal is received from the path search request unit 120, the whole network path search unit 130 searches for all possible paths in the sub-network units. The whole network link selecting unit 140 refers to a subnetwork previously stored in the whole network database 150 and the link information connecting the subnetworks within the range of a path that can be implemented by the whole network path searching unit 130. Browse the links in between to select the best one. The whole network database 150 stores subnetwork identifiers representing the actual network details, and subnetwork identifiers and node identifiers at both ends of the link connecting them. The sub-network capable path processing unit 160 requests or receives a possible path for each sub network according to the sub network path request information applied from the whole network link selection unit 140. In addition, the path combination unit 170 searches for possible paths in the paths of the entire network by combining the path information in the sub-networks applied from the sub-network capable path processing unit 160 with each other. The operator constraint applying unit 180 removes a path that does not satisfy the constraint from the n path information in the entire network applied by the path combining unit 170, and outputs the optimal path and possible n path information.

On the other hand, the sub-network event receiving unit 210 receives a command from the operator, such as the addition or deletion of nodes and links that change the network shape. The sub network path search request unit 220 receives a path search request signal from the operator. The sub-network path search unit 230 searches for all possible paths in the node unit when the path search request signal is received from the sub-network path search request unit 220. The sub-network link selector 240 searches for a link between nodes within a range of possible paths obtained by the sub-network path search unit 230 by referring to the link information previously stored in the sub-network database 250 and then selects an optimal link. Select. The subnetwork database 250 stores node identifiers representing the actual network details and node identifiers at both ends of the link connecting them.

Accordingly, the sub network path searching apparatus 200 implements a sub network by a network splitting policy in consideration of the convenience for managing a large public network and the capacity of the managed node, and one path searching unit 230 for each corresponding sub network. ) So that search of the paths can be processed in parallel. In addition, the node of the sub-network path search apparatus 200 maintains only the identifier of the switch, and the link represents the trunk of the switching period, so that only the identifiers of the nodes located at both ends of the trunk can be kept to reduce the memory usage.

An operation process of the present invention having such a configuration will be described below with reference to FIG. 3.

First, the network event receiver 110 adds / deletes a node, adds / delete a physical link, and adds / deletes a logical link in order to always match the information maintained by the apparatus 100 for searching the network with the state of the actual network. Receive the command to change the network shape. In addition, the entire network path search unit 130 receives the route request information from the entire network path search request unit 120 (step 100). The entire network path search unit 130 may display edges representing connections between vertices. Search all possible paths in sub-network units by searching the sub-network identifier and the node identifier at both ends of the connection between the sub-networks (step 110). Then, the whole network link selection unit 140 includes a link included in the trunk line. It selects the optimal link among the links between the sub-networks by managing the identifier of the sub-network and extracting the detailed information necessary for the optimal link selection by referring to the link information stored in the whole network database 150. (Step 120). The possible path processing unit 160 requests the sub-network path to the sub-network path search apparatus 200 according to the sub-network path request information applied from the whole network link selection unit 140. (Step 140) Next, the sub-network circa The navigation device 200 searches for the optimum route in the node unit in the sub-network (step 150)

Meanwhile, the sub-network capable path processing unit 160 of the entire network path search apparatus 100 receives possible paths from the sub network path search unit 200 (step 160), and optimizes the selected sub network path search apparatus 200. It is determined whether all of the responses to the path have been received (step 170). When all of the responses from the sub-network path search apparatus 200 are received, the path combining unit 170 combines all possible paths for each sub-network to each other. Search for possible paths in the network (step 180). Then, the operator constraint applying unit 180 deletes the corresponding path from the candidate path group when the optimal link does not exist, and sets the priority from the possible paths. The path is displayed (step 190). Then, the whole network path search request unit 120 responds to the operator with the optimal path and possible paths (step 200).

FIG. 4 illustrates a detailed operation of the apparatus 200 for searching a sub-network path for searching for an optimal path for each node in the above-described sub-network (step 150).

The sub network event receiving unit 210 forms a network such as node addition / deletion, physical link addition / deletion, logical link addition / deletion, so that the information maintained by the sub network path search apparatus 200 always matches the state of the actual network. Receive a command to change. Then, the sub network path search request unit 220 of the sub network path search apparatus 200 receives the path request information for the corresponding sub network from the whole network path search apparatus 100 (step 151). When the path request signal is applied from the sub-network path search request unit 220, the path search unit 230 searches for all possible paths on a node-by-node basis by searching for node identifiers at both ends of the node-to-node connection (step 152). The sub-network link selector 240 manages the identifier of the link included in the trunk line, and extracts detailed information necessary for selecting an optimal link by referring to the link information stored in the sub-network database 250, thereby linking nodes. Select the optimal link among the steps (step 153). Subsequently, the sub-network path search requesting unit 230 prioritizes and arranges possible paths in the sub-network. Paths in the candidate group do not have paths through the same nodes, and the number of nodes (= hop counters) on one path may be different, so it is sorted based on this to obtain an optimal path. That is, the path having the smallest hop counter among the optimal path candidate groups is selected as the optimal path. Subsequently, possible paths in the subnetwork are transmitted to the entire network path search apparatus 100 (step 155).

As described above, the present invention does not require the process of calculating the cost when searching for the path, and the process of matching the network state and the attribute values of the link with the actual network state necessary for the cost calculation does not need to be performed. You can navigate. In addition, since it provides the operator with the N possible paths as well as the optimal path, it provides the effect of enabling the path selection according to the operation policy.

1 is a view showing the structure of a general high speed communication network.

2 is a block diagram of an apparatus for providing a path in an asynchronous transmission network according to the present invention;

3 is an operation flowchart of a path providing method of an asynchronous transmission network according to the present invention;

4 is a flowchart illustrating an operation of a method for searching a sub network path of FIG. 3.

Claims (10)

A plurality of sub-network path search apparatuses that search for an optimal path on a node-by-node basis when selecting a path for a corresponding sub-network, and transmit a possible path in the sub-network; And Search for all paths in a sub-network unit, request a path to a corresponding sub network path search device among the plurality of sub network path search devices, and combine possible paths for each sub network received from the corresponding sub network path search devices in the entire network. An apparatus for providing a path in an asynchronous transmission network, comprising: an apparatus for searching an entire network for displaying an optimal path. The apparatus of claim 1, wherein the whole network path searching apparatus is An entire network path search unit for searching all paths in sub-network units according to the path request; A whole network link selection unit for selecting an optimal link between sub-networks within the range searched by the whole network path searching unit and outputting sub-network path request information; A sub-network capable path processing unit requesting the sub-network path search apparatus for a path available for each sub-network according to the sub-network path request information applied from the whole network link selection unit; A path combination unit that combines the sub-network capable paths applied from the sub-network capable path processing unit and converts the paths into possible paths in the entire network; And And an operator constraint applying unit configured to calculate an optimal path by removing a path that does not satisfy the constraint in the entire possible network applied from the path combination unit. The apparatus of claim 2, wherein the whole network path searching apparatus is An overall network event receiver configured to receive at least one command for changing the shape of the network during addition and deletion of nodes and links; An entire network path search request unit for receiving a path request from an operator; And And a whole network database storing subnetwork identifiers representing detailed network information and sub-network identifiers and node identifiers at both ends of a link connecting them. The apparatus of claim 1, wherein the sub network path searching apparatus A sub network path searching unit for searching all paths in units of nodes when a path request is made for the corresponding sub network from the whole network path searching apparatus; And And a sub-network link selector for selecting an optimal link by searching for a link between nodes within a range of the path searched by the sub-network path searcher. The apparatus of claim 4, wherein the sub network path search apparatus Sub network event receiving unit for receiving at least one command for changing the shape of the network during the addition and deletion of nodes and links; A sub network path search request unit receiving a path request from an operator; And And a sub-network database for storing node identifiers representing detailed network information and node identifiers at both ends of a link connecting them. A first step of searching for all paths of the sub-network units and requesting a possible sub-network-specific path from the corresponding sub-network path searching apparatus; A second step of the sub-network path search apparatus searching for all paths of each node in the sub-network to select an optimal link according to a request of the available paths for each sub-network, and transmitting possible paths in the sub-network; And And a third step of displaying an optimal path in the entire network by combining possible paths in the received sub-network. The method of claim 6, wherein the first step Searching all paths in sub-network units according to the path request; Selecting an optimal link among the links between subnetworks of the searched path; And And transmitting sub-network capable path request information to a corresponding sub network. The method of claim 6, wherein the second step Searching all paths in the node unit when requesting a path to the corresponding subnetwork; Selecting an optimal link among the links between the nodes; And transmitting the possible paths for each sub-network by sorting the possible paths in order of priority in the sub-network. The method of claim 6, wherein the third step Combining possible paths for each sub-network to calculate a possible path in the entire network; And And providing an optimal path by assigning priorities of possible paths in the entire network. The method of claim 9, The priority order is a path providing method of an asynchronous transmission network, characterized in that the path is selected from the optimum hop hop path is the minimum.