KR100343774B1 - Method of multicast route allocating for delay-sensitive service using VP branching node in ATM networks - Google Patents

Abstract

The present invention relates to a multicast path allocation method applicable to an ATM communication network. In particular, a multicast path for delay-sensitive services is allocated, but the total link utilization efficiency is improved by using a VP tree structure and a multicast tree calculation is performed. The purpose is to provide a method for allocating a multicast path for delay-sensitive services using VP branching nodes in an ATM network that reduces the processing complexity required for the network.

According to the present invention, a first step of receiving a physical network configuration information to create a physical network configuration table, the virtual path branching node table; A second step of integrating the virtual path branching node by obtaining the least cost connection path from the multicast group configuration request; And a third step of notifying the source node of the path allocation result after allocating the minimum delay path, and a method for allocating a delay-sensitive service multicast path using a VP branching node in an ATM communication network is provided.

Description

Method of multicast route allocating for delay-sensitive service using VP branching node in ATM networks}

The present invention relates to a multicast path allocation method applicable to an ATM communication network. In particular, a multicast path for delay-sensitive services is allocated, but the total link utilization efficiency is improved by using a VP tree structure and a multicast tree calculation is performed. The present invention relates to a method of allocating a multicast path for delay-sensitive services using a VP branching node in an ATM network that reduces the processing complexity required for the network.

ATM networks must support multicast services, such as VOD and conferencing services, which must provide point-to-multipoint connectivity.

In the case of a multicast service requiring a point-to-multipoint connection shape, data transfer from any source node to multiple destination nodes must be performed, resulting in an absolutely higher total bandwidth than the unicast service.

Therefore, in order to increase network usage efficiency, a multicast routing method that efficiently uses network resources is required.

In addition, due to the high speed of transmission technology and the development of optical transmission technology, the cost of using the bandwidth of the link is decreasing, whereas the cost of processing and buffering is relatively expensive. There is a need to reduce complexity.

Existing methods for multicast routing are mainly intended for optimal use of bandwidth, and are primarily intended for path allocation for non-real-time services in computer networks.

For each link in the network, we define the cost function considering the routing criteria and find the path that minimizes the total cost of connecting the source node and the group members.

In the conventional method, the minimum cost connection path between the source node and the group members on the network is obtained, but in order to reduce the calculation, the first method is to simplify the network with only the source node and the group member nodes, and then the most cost until all the member nodes are connected. We add these cheap links one by one to find the least cost link.

Therefore, the computational cost can be reduced compared to finding a connection path for the entire network. However, since it does not include the role of a branching node with intermediate cell copying, there is a limit to improving the link utilization efficiency. The problem is that the time it takes to find the path is too complicated to investigate the delay limit.

The present invention has been made to solve the problems of the prior art as described above, by configuring a cost-optimized VP tree for each multicasting group using switches having a VP multicasting function in the network when multicaster path allocation In order to improve the efficiency of use and reduce the processing complexity required for path allocation, for each VP branching node at initialization, information about the network nodes that can be distributed through that branching node is also retrieved in advance. For each multicast group, we obtain a path-saving tree via the VP branching nodes and then examine the delay constraints for the real-time services to determine which group members exceed the maximum allowed delay, regardless of the VP branching node. Allocate a new minimum delay path between the group and its group members The purpose of the present invention is to provide a method of allocating a multicast path for delay-sensitive services using a VP branching node in an ATM network that can reduce the processing complexity of economic path search.

1A to 1C are exemplary views illustrating the configuration of an asynchronous transmission mode communication network to which the present invention is applied.

2A to 2C are flowcharts illustrating a method for allocating a delay-sensitive service multicast path using a VP branching node in an ATM communication network according to an embodiment of the present invention;

3 is a functional block diagram of a VP multicasting management server for multicast path allocation to which the present invention is applied.

♠ Explanation of symbols on the main parts of the drawing ♠

301: Multicast Path Management Process

302: Multicast Network Management Process

303: Network Modeling Process

304: Multicast Path Creation Process

306: network resource management function block

307: network state management function block

308: root management function block

309 physical network modeling function block

310: Virtual Path Branching Subnet Modeling Function Block

311: network model update function block

312 link cost calculation function block

313: Complete Network Modeling Function Block

314: Minimum Cost Path Calculation Function Block

315: maximum delay verification function block

316: physical network configuration table

317: Virtual Path Branching Node Table

318: Virtual Path Multicasting Mesh Table

319: Virtual Multicasting Tree Table

According to the present invention for achieving the above object, a first step of receiving a physical network configuration information to create a physical network configuration table, the virtual path branching node table; A second step of integrating the virtual path branching node by obtaining the least cost connection path from the multicast group configuration request; And a third step of notifying the source node of the path allocation result after allocating the minimum delay path, and a method for allocating a delay-sensitive service multicast path using a VP branching node in an ATM communication network is provided.

In addition, according to the present invention, a first step of creating a virtual path branching node table after receiving the physical network configuration information to the computer to create a physical network configuration table; A second step of integrating the virtual path branching node by obtaining the least cost connection path from the multicast group configuration request; And after allocating the minimum delay path, a computer-readable recording medium having recorded thereon a program for executing the third step of notifying the source node of the result of the path assignment.

Hereinafter, a preferred embodiment of a method for allocating a delay-sensitive service multicast path using a VP branching node in an ATM communication network according to the present invention will be described in detail with reference to the accompanying drawings.

The present invention reduces the total link usage by using a VP branching node when allocating a multicast path for real-time services in an ATM network, but the VP multi-service for delay-sensitive services where the total end-to-end delay does not exceed the maximum allowable delay. The present invention relates to a method for obtaining a cast tree while reducing processing complexity. The method of searching for a VP branching node having a minimum delay for a multicast group member when obtaining a multicast path in an ATM network and a method of allocating a VP multicast tree using the same It consists of.

If there is a multicaster service request for the ATM network as shown in FIG. 1A, the path of FIG. 1C in the form of a VP tree for multicasting is allocated by the procedures of FIGS. 2B and 2C.

The functional block for multicaster path allocation is configured as shown in FIG. In order to find an economic path using a VP branching node in the network, the VP branching node which copies cells to all nodes in the network at the time of initialization is searched and determined. The procedure is illustrated in FIG. 2B.

1A to 1C are diagrams illustrating the configuration of an asynchronous transmission mode communication network to which the present invention is applied.

The network consists of thirteen VP / VC switching nodes (N1001 to N1013), fifteen links (1101 to 1115) connecting them, and a multicast management server (1301).

A (N1001), B (N1002), E (N1006), and F (N1010) nodes among the nodes in the figure are VP branching nodes that support a copy function for a VP cell, and the remaining nodes do not have a VP cell copy function. Do not.

The links 1101 to 1115 connecting the nodes are physical links having an allocable bandwidth and an inherent delay characteristic.

The multicast management server 1301 retrieves and stores information about which VP branching node each member receives from the branching node for the multicast group requested by the user, and calculates a VP multicast tree using the same. I'm a server.

FIG. 1B is a primary network modeling at the VP level to obtain a multicast tree to support any multicasting group (s, m1, m2, m3, m4, m5, m6) from the physical network.

That is, by using only information on the VP branching node to be connected to each group member from the multicast management server 1301, the network configuration is simplified to only nodes that participate in the multicast tree connection.

In this example, m1 (1202) is branched from node B (N1002), m2 (1203) is I node (N1007), m3 is J node (N1008), m4 (1205) and m5 (1206) and m6 (1207). ) Is assumed to be branched from the F node (N1010).

Therefore, a network configuration for finding a multicast tree to support this multicast group can be simplified to a VP link connecting five nodes and them, as shown in FIG.

In the figure, the VP link 1407 connecting the A node N1001 and the F node N1010 may pass through the physical link 1101-1104-1115 or may be assigned to pass through the physical link 1101-1104-1108-1112. have.

In addition, for each VP link, the cost value Ce and delay value De for the use of network resources are unique. For example, the cost Ce (A, B) 1501 and the delay value De (A, B) 1502 are defined for the VP link 1401 connecting node A1001 and node B1002.

The cost function 1501 may be defined in consideration of various cost incurring factors such as bandwidth requirements and the number of physical links through the VP link as costs for link use.

The delay function 1502 is a value representing the delay characteristics of the VP link and may be defined in consideration of the total length of the VP link, the switching delay experienced by the unit traffic, and the propagation delay.

FIG. 1C is an example of allocating a VP multicast tree path having an optimal cost from the network model of FIG. 1B but not causing the end-to-end delay to exceed the allowed maximum value.

In other words, for the m1 1202, the flow 1 path through the B node N1002 is allocated through the VP link 1401 at A (N1001), and the flow 2 path is allocated to the m3 to m7.

2A to 2C are flowcharts illustrating a method for allocating a delay-sensitive service multicast path using a VP branching node in an ATM communication network according to an embodiment of the present invention.

2A is an initialization process for supporting a multicast service.

Process 201 is a process in which initialization data for the physical network configuration is input to the network resource management function block Net_Rsc_Manager (3 degrees, 306) by the network manager.

Network configuration information to be input includes node number, connection link for each node, available bandwidth and cost and delay characteristics for each link, presence and absence of VP cell copy function for each node, and subscriber access.

The input network configuration information is transferred from the network resource management function block Net_Rsc_Manager (3 degrees, 306) to the network modeling process (Network_Model_Proc) (3 degrees, 303).

The network modeling process (Network_Model_Proc) (3 degrees, 303) creates a physical network configuration table (Tbl_Phy_Net) (3 degrees, 316) using the received physical network configuration data (202).

Subsequently, initialization for supporting the multicast service is performed by creating a VP branching node table (Tbl_VP_bran) (3 degrees, 317) for each VP branching node (203).

The VP Branching Nodes Table (Tbl_VP_bran) (3 degrees, 317) calculates and records information about costs and average delays for each of the VP Branching Nodes for the underlying nodes that can be connected through that Branching Node. Table.

A procedure diagram for creating a VP branching node is described in FIG. 2B.

FIG. 2B illustrates the VP Branching Node Table (Tbl_VP_bran) (3 degrees, 317) by the Virtual Path Branching Subnet Modeling Function Block (Make_VP_bran_subnet) (3 degrees, 310) unit for generating information on the underlying subnetwork of the VP Branching nodes. ) Is the process of making.

First, a server network that can be connected from each VP branching node Vb (i) is configured from the physical network configuration table Tbl_Phy_Net (3 degrees, 316) (211).

When the server network for Vb (i) is configured, the minimum delay path is searched for Vb (i) and all nodes on the server network (212).

The minimum delay path can be found by using the shortest path search algorithm using the delay value of each link.

The average delay value and the cost are calculated and recorded for the found path (213). This process is performed for all nodes on the Vb (i) server network (214, 215).

When 211 to 215 processes are repeatedly performed for all VP branching nodes of the physical network (216 and 217), the search for the VP branching node is finished, and the search results are classified and stored for each user access node (218).

Therefore, when an arbitrary multicast group is newly formed, it is easy to find out which VP branching node the stream should be distributed to the user access node to which the group member is connected.

2C illustrates a process of calculating and assigning a VP multicast tree by requesting a multicast group configuration.

After initialization, the multicast group configuration request is waited. When the multicast group configuration request arrives from the user (221, 222), the multicast route creation process (Multi_Router_proc) (FIG. 3, 305) calculates a VP tree for multicast. To allocate.

Users requesting multicast group configuration should present the maximum allowed delay between source nodes, group members and services.

When a multicast group configuration request occurs, the multicast route creation process (Multi_Router_proc) (FIGS. 3 and 305) sends the VP branching node information that will be responsible for distributing information for all group members m (i). Tbl_VP_bran) (FIG. 3, 317) (223).

Subsequently, the complete network model function block Tbl_Clos_mul (FIGS. 3 and 313) is constructed using the source node s and the VP branching nodes found in step 223 (224). Fully connected network is a full-mesh connected network model with minimum cost connection path between source node s and each VP branching node, which simplifies the network to find multicast paths while reducing computation.

Finding the least cost connection path between two nodes A and B is obtained by repeatedly adding the nearest node from node A to node B on the VP network.

For example, if the node closest to node A (which can be connected at the lowest cost) is node C, then select A-C. Then consider A-C as if it were a single node and find the next nearest node. For example, if the C-D connection path is the closest (A-C-D) connection path is found. This process is repeated until the A-B node is connected.

When the virtual path multicasting network table (Tbl_VP_Mul_Net) 318 is completely connected between the VP branching nodes connecting s and all group members, the cost and delay values of the VP paths connecting the nodes are calculated and recorded. (225).

In the VP connection path constituting the fully-connected network model, one or more VP connections of the VP virtual network may be directly connected, so the delay and cost values are accumulated values of respective VP paths.

Since a fully connected network is formed in a full-mesh fashion, a minimum cost multicast path (Tbl) is allocated therefrom (226). The process of obtaining the least cost multicast path is obtained by repeating process 224 until all VP branching nodes are connected.

In this way, once the least cost multicast connection path is obtained, the VP multicasting tree table (Tbl_VP_Mul_Tree) connecting the source node and each multicast group member by combining the result and the group member connection information through the VP branching node (Figure 3). 319) (227).

Once the VP multicast tree is created, the average delay with the source node s is calculated for each group member m (i) (228).

If the average delay value is larger than the maximum allowable delay, the economic path passing through the branching node is abandoned and an additional minimum delay path is allocated between s and m (i) (229).

When the delay limit check is completed for all group members m (i), the source node is notified of the path allocation result (230).

3 is a block diagram of a multicast management function block for multicast path allocation according to the present invention.

The multicast path management process (Mul_Manager_Proc) 301 is composed of network resource management, network modeling management, path allocation and path management functions for multicast path allocation.

The multicast network management process (Network_Manager_Proc) 302 performs initialization and management of network configuration and status data, and route allocation management. The network resource management function block (Net_Rsc_Manager) 306 and the network status management function block (Net_Status_Manager) ( 307, a route management function block (Route_Manager) 308.

The network resource management function block (Net_Rsc_Manager) 306 passes the network configuration and resource characteristic data to the network modeling process (Network_Model_Proc) 303 as a management function for information on physical network configuration and link cost or delay characteristics. Allows you to model

A network status management function block (Net_Status_Manager) 307 is a function of receiving and processing status data of a node or a link, which is a network component system, from nodes, and updating a change in status in a network model table.

The route management function block (Route_Manager) 308 receives a request for multicast path allocation from a node or an operator, verifies the content of the request, and requests the relevant path allocation function to perform the request.

The network modeling process (Network_Model_Proc) 303 is a process of constructing a network model for multicast path allocation using network configuration and resource characteristic data and network state data transferred from the multicast network management process (Network_Manager_Proc) 303. .

Physical network modeling function block (Create_Phy_Net) 309, virtual path branching subnet modeling function block (Make_VP_bran_subnet) 310, network model update function block (Update_Net_Mdl) 311, link cost calculation function block (Compute_LK_Cost) 312 It consists of four functions.

The physical network modeling function block (Create_Phy_Net) function 309 creates a physical network model table (Tbl_Phy_Net) that records information on nodes and links constituting the physical network.

The Virtual Path Branching Subnet Modeling Function Block (Make_ VP_bran_subnet) 310 function calculates information for each VP branching node about the underlying nodes that can be connected through that branching node, as well as values for cost and average delay. Create a VP branching table.

The link cost calculation function block (Compute_LK_Cost) 312 function calculates the cost and delay values for each VP path allocated for multicast. The cost and delay values are automatically generated from the physical configuration data or defined by an operator. You can also apply

The network model update function block (Update_Net_Mdl) 311 is a function of changing a physical network and a VP branching node table when a network state changes or an operator request.

The multicast route creation process (Multi_Router_Proc) 304 is a functional block that allocates a route when a multicast request of a user is input.

It is composed of three functions: full network modeling function block (Make_Closure_Net) 313, minimum cost path calculation function block (Make_Shortest_Route) 314, and minimum delay verification function block (Chk_Delay_Route) 315.

The full network modeling function block (Make_Closure_Net) 313 simplifies the connection between the VP branching nodes in full-mesh form through the least cost path from the physical network configuration table, the VP branching node table, and the multicast group data. It configures the network, calculates the cost and delay value of the VPC (Virtual Path Connection) connecting each node and writes it to the virtual path multicast network table (Tbl_VP_Mul_Net) 318.

The minimum cost path calculation function block (Make_Shortest_Route) 315 is a function of finding the minimum cost path connecting the source node s and the branching node in the simplified connection network created by the minimum cost path calculation function block 314.

As described in detail above, a method for allocating a delay-sensitive service multicast path using a VP branching node in an ATM communication network according to the present invention is performed by allocating a path using a VP branching node when assigning a multicaster path in an ATM network. It improves the efficiency of use, and also searches for and specifies the VP branching node with the minimum delay for the network nodes at initialization, and it is economical for group members exceeding the maximum allowable delay for the found VP tree path. By allocating the least cost path instead of the path, processing complexity is reduced compared to the conventional method.

The method proposed in the present invention can be applied to a real-time service multicasting path allocation method having a delay time limit of private and public ATM networks.

In the above description, a technical idea of a method for allocating a delay-sensitive service multicast path using a VP branching node in the ATM communication network of the present invention has been described with the accompanying drawings. It does not limit the invention. In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

Claims (5)

A first step of receiving a physical network configuration information and creating a physical network configuration table, and then creating a virtual path branching node table; A second step of integrating the virtual path branching node by obtaining the least cost connection path from the multicast group configuration request; And After allocating the minimum delay path, a method for allocating a delay-sensitive service multicast path using a VP branching node in an ATM communication network comprising a third step of notifying the source node of the path allocation result. The method of claim 1, The process of creating the virtual path branching node table of the first step, A fourth step of configuring a subnetwork connected to the virtual branching node from the physical network configuration table; A fifth step of searching for a minimum delay path between the virtual path branching node and all nodes connected to the subnetwork; A sixth step of calculating and recording an average delay and a cost value for the found connection path; A seventh step of determining whether a path search for all paths of the sub-network is completed; An eighth step of repeating the fifth step if the path search for all the paths is not completed as a result of the determination of the seventh step; A ninth step of determining whether the search for all the virtual path branching nodes is completed when the path search for all the paths is completed as a result of the determination of the eighth step; A tenth step of repeating from the fourth step if the search for the virtual path branching node is not completed as a result of the determination of the ninth step; And As a result of the determination of the tenth step, if the search for the virtual path branching node is completed, an eleventh step of sorting and storing the search result for the user access node includes a delay using the VP branching node in the ATM communication network. How to assign multicast paths for sensitive services. The method of claim 2, The second step, A twelfth step of receiving a multicast grub configuration request; A thirteenth step of retrieving virtual path branching node information for all destination m (i); A fourteenth step of constructing a perfect network model with a source node and a virtual path branching node; Calculating a cost and a delay value for all virtual paths; And A method for allocating a delay-sensitive service multicast path using a VP branching node in an ATM network comprising the sixteenth step of integrating a least cost connection path and a virtual path branching node. The method of claim 3, wherein The third step, A seventeenth step of calculating an inter-source average delay for the destination m (i); An eighteenth step of determining whether the average delay time is less than the maximum allowable delay time; A nineteenth step of abandoning the economic path if large and allocating a minimum delay path between the source node and the destination m (i) as a result of the determination of the eighteenth step; A twenty-step step of determining whether the delay limit for all destination m (i) has been investigated; A twenty-first step of repeating from the sixteenth step if it is not investigated as a result of the determination of the twenty-step; A twenty-second step of notifying the source node of the path allocation result if the result of the determination in the twentieth step is examined; A twenty-third step of judging whether the delay limit for all destination m (i) is investigated if it is small as a result of the determination in the eighteenth step; A twenty-fourth step of repeating from the sixteenth step if it is not investigated as a result of the determination in the twenty-third step; And And a twenty-fifth step of notifying the source node of the route allocation result when the determination result of the twenty-third step has been investigated. On your computer, A first step of receiving a physical network configuration information and creating a physical network configuration table, and then creating a virtual path branching node table; A second step of integrating the virtual path branching node by obtaining the least cost connection path from the multicast group configuration request; And A computer-readable recording medium having recorded thereon a program for executing a third step of notifying a source node of a path allocation result after assigning a minimum delayed path.