KR101001357B1 - Method and Apparatus for constructing transmission tree - Google Patents

Abstract

The present invention relates to an overlay multicast tree construction method and a transmission tree management apparatus, the method comprising: identifying an operation mode of the agent; And a tree construction step of determining an overlay policy based on the identified operation mode, and configuring a transport tree of the agents according to the determined policy. You can configure the transport tree.

Description

Method and Apparatus for constructing transmission tree

The present invention relates to overlay multicast, and more particularly, to a transmission tree construction method and a transmission tree management apparatus in an overlay multicast service.

Group transmission methods for providing real-time IPTV (Internet Protocol Television) services on the Internet and general-purpose networks can be largely divided into unicast and multicast. The unicast method is a method of transmitting a plurality of broadcast channels to a small number of user groups, and the multicast method is a method of transmitting a small number of broadcast channels to a plurality of user groups.

IP multicasting, which uses an IP address scheme for multicasting, can reduce redundant transmission of the same data in a network. However, due to structural problems, IP multicast support of all configured routers, and management cost issues for address allocation, there is a limitation that only a large Internet service provider (ISP) or a provider using a local network can be used.

In addition, as many unspecified individuals have recently distributed and serviced broadcast contents, very many network resources are needed to accommodate the existing unicast scheme to support such services. This may fundamentally limit the opportunities for participation in IPTV broadcasting by individuals or small groups.

Because of these problems, methods to minimize network burden have been proposed through overlay-based application layer multicast routing. Overlay multicast is to install multiple agents in the current unicast-based Internet network, organize related transceivers and agent systems into a tree structure, and then sender multi-send between multiple receivers using the relay function of the agent. It is to enable the transmission of the cast data, which means a kind of multicast transmission technology in the upper layer (overlay).

Through this overlay multicast transmission technology, multicast application services such as internet live broadcasting, distance education, and video conferencing can be realized in a unicast network without a separate multicast network. According to the overlay multicast transmission technology, transmission nodes of the same purpose relay relay multimedia data to achieve breakthrough multicast purposes compared to the unicast scheme.

Here, the degree of enhanced performance of overlay multicast is differentiated by a method of setting a transmission path that is different from the type of application service to be used, and the method is not limited to simply improving the performance of the multicast itself, but to the application service to be implemented. It is implemented in different ways. For example, in case of an IPTV application service that emphasizes real-time, the transmission structure is directed to minimize the relay step. Therefore, the gain on the network is not large compared to the actual unicast, but there may be a method of minimizing the transmission delay. On the contrary, in view of the large-scale content distribution application, a large number of relay structures may be induced to minimize the amount of network distribution. Can be done.

Therefore, the transmission structure method has advantages and disadvantages in different ways depending on the application system, size, and purpose to be built, and the frequency and timing of occurrence of relay or user node are also important factors that determine the performance of the configuration.

As a result, there are many factors to consider in establishing a multilateral broadcasting service in a peer-to-peer (P2P) network environment consisting of end-to-end nodes. There is a limit to what you offer.

Recently, P2P researchers have been researching how to improve the performance by utilizing user behavior and sharing characteristics. For example, the BitTorrent method, which allows more sharing when downloading content, can be faster. Same case.

 P2P or overlay multicast services can be used for various multicast applications, but there are many cases of efficient transmission, management structure creation and control, and above all, user behavior such as user's subscription, withdrawal and sharing. The following variables greatly affect the performance of the application system.

Accordingly, in order to improve the technical efficiency reflecting these variables in the area of the relevant technology, researches are being made on the area of transmission structure optimized for each target system and reflecting the variables.

The present invention is derived from such a background. In providing a multi-party real-time IPTV broadcasting service in an overlay transmission structure, a tree construction method and a transmission tree applying a method of creating a transmission structure of different policies to respective configuration nodes having different operation modes It is an object to provide a management device.

In addition, an object of the present invention is to provide a tree construction method and a transmission tree management apparatus capable of accommodating all the configuration nodes in a broadcast service system to provide an IPTV service with stable, general purpose, and optimized service performance.

The technical problem is to identify the operation mode of the agent; And a tree constructing step of determining an overlay policy based on the identified operation mode, and constructing a transport tree of the agents according to the determined policy.

In this case, the method may further include a rating step of assigning a rating to each agent by reflecting the resource sharing capability of the agent, and the tree constructing step may determine an overlay policy based on the rating information granted to the agent. It is characterized by.

In addition, the operating mode of the agent is a service providing mode including a single serving mode having one output stream channel and a multiple serving mode having multiple output stream channels, a single having a single input stream channel and no output stream channel. The service receiver mode including a reception mode and a reception relay mode for outputting broadcast content input through one input stream channel to a plurality of output stream channels, and providing the service including a plurality of input channel streams and a plurality of output channel streams. And a relay mode for relaying broadcast content transmission between a mode agent and the service receiving mode agent.

On the other hand, the technical problem is an information receiving unit for receiving agent information from the agent; An operation mode determining unit configured to determine an operation mode of the agent based on the received information; A class allocator configured to assign a class to the agent by reflecting an operation mode of the agent identified by the operation mode determiner; And a tree constructing unit constituting a transmission tree between the agents on the basis of the assigned class information.

In addition, when receiving a broadcast registration request or broadcast reception request from the agent, the list providing unit for generating a candidate node list based on the rating information of the agent according to the received request to provide to the agent; The tree constructing unit obtains selected node information from the provided candidate node list from the agent, and configures a transmission tree by reflecting the obtained information.

IPTV and Internet broadcasting application platform according to an embodiment of the present invention is optimized for the application by reflecting the various user behavior state in the configuration of the transmission tree, compared to the overlay multicast method in which all configuration nodes are controlled by the same policy You can construct a tree. In addition, by using an incentive policy that minimizes transmission delays in the construction of transport trees and places them on the minimum user tree link to nodes and groups that share a large amount of resources, and that they tend to leave minimally, Through this, it is possible to maximize the scalability of the system by inducing resource sharing, which is the biggest advantage of the peer-to-peer overlay method. In addition, a content-based transmission tree may be configured to configure a community-based service delivery tree.

Meanwhile, in the overlay multicast scheme, an algorithm used to construct a tree according to a specific policy may increase the performance of an application service targeted for a service. However, due to the calculation amount added for the optimized tree configuration, the control data necessary for the tree configuration in the system should be added, and thus there is a disadvantage in that resource allocation and time for setting up the session are required. However, according to the present invention, since the tree is configured by reflecting the grade information allocated to each agent, it is not necessary to exchange additional control messages for a separate transport tree configuration policy, thereby saving resources and time. In addition, it is possible to increase efficiency by minimizing tree recovery costs due to node detachment and change, which are the main elements of overlay multicast.

The foregoing and further aspects of the present invention will become more apparent through the preferred embodiments described with reference to the accompanying drawings. Hereinafter, the present invention will be described in detail so that those skilled in the art can easily understand and reproduce the present invention through these embodiments.

1 is a block diagram showing the configuration of a transmission tree management apparatus according to an embodiment of the present invention. In this embodiment, the transport tree management apparatus establishes a tree control channel with a plurality of agents in the system to perform overlay multicast tree configuration and management. The transport tree management apparatus receives a broadcast transmission request, a broadcast reception request, a tree access request message, and the like from agents through a configured tree control channel, and transmits a response message accordingly.

According to the response message from the transport tree management apparatus, each agent may form a data channel with each other and perform data transmission through the formed data channel.

In more detail, as illustrated in FIG. 1, the transmission tree apparatus includes an information receiver 100, a node register 120, and a tree constructing unit 130.

The information receiving unit 100 receives agent information through a tree control channel from a plurality of agents in the system. In the present embodiment, the agent information includes at least some of the IP address, port information, input stream channel information and output stream channel information, and bandwidth information of the agent. However, it is not limited thereto.

The node register 120 grasps information of agents in the system. In more detail, the node register 120 includes an operation mode determiner 122 and a class allocator 124.

The operation mode determiner 122 determines an operation mode of the corresponding agent based on the agent information received by the information receiver 100. In the present embodiment, the operation mode determiner 122 may divide agents into service providers (PPs), relays, and service receivers according to their operation modes. In more detail, the service provider is divided into a single provision mode and a multiple provision mode, and the service receiver is divided into a single reception mode and a reception relay mode. Each such operation mode will be described later in more detail.

The class assignment unit 124 reflects the operation mode information of the agent identified by the operation mode determination unit 122 and assigns a class to each agent. In addition, the class allocator 124 allocates different classes by reflecting resource sharing capabilities such as network and system resource information and error frequency of each agent. In the present embodiment, the rank assigning unit 124 is assigned a lower rank number as the number of output streams increases. In addition, the higher the sharing range of the hierarchical content, the lower the rank number. That is, the grade allocation unit 124 assigns a grade number to each agent according to the resource sharing capability of the network and the system and the sharing range of the broadcast content provided.

The class information allocated by the class assigning unit 124 may be used as a comparison value when determining the transmission / reception rights of the agent, that is, the parent node relay node when constructing a new overlay tree.

The tree constructing unit 130 configures the transmission tree by reflecting the class information of the agent allocated by the class allocating unit 124. Then, the tree configuration information is delivered to the agents so that the agents form a bidirectional data transmission channel according to the tree configuration information.

The tree constructing unit 130 reflects the grade information to form a tree. That is, the performance of the overlay tree is improved by having a node having a large resource sharing capability at a higher depth on the tree.

In addition, nodes with low resource sharing capability are located at a lower depth, that is, at the end of a lower tree so that a relatively high transmission delay (RDP) from a source can be obtained. Accordingly, the tree recovery performance can be improved by placing agents that do not share resources with other agents, which are statistically deviated and changed, at the end of the tree.

The transport tree management apparatus according to the present invention further includes a list providing unit 140. When the list providing unit 140 receives a broadcast registration request or a broadcast reception request from an agent, the list providing unit 140 generates a parent node candidate list based on the rating information of the agent that transmitted the request and provides it to the agent.

Thereafter, the agent sending the request may select an optimal parent node by reflecting measurement information among the provided parent node candidate lists. The tree constructing unit 130 obtains optimal parent node information selected from the agent and constructs a transmission tree based on the obtained parent node information.

In this embodiment, the agents in all modes of operation may be implemented in the same structure. This is because the mode of operation is determined as the user uses the agent according to his purpose. In this case, the number of input stream channels and output stream channels may vary according to system and network resource measurement values reported to the transport tree management apparatus when the program is executed.

The transmission tree management apparatus according to an embodiment of the present invention evaluates an operation mode and a grade by using information on usage, performance, and resource sharing degree of each agent through such information. Then, the tree configuration instruction is transmitted to the agent to configure the overlay transmission tree according to the appropriate policy by reflecting the operation mode and class information. That is, even if each agent joins at the same time in the transport tree structure, it has different tree depths according to the purpose, performance, and resource sharing of the agent. Accordingly, the relative transmission delay and the sharing degree from the service provider may be adjusted. In addition, during tree recovery, the tree management apparatus forcibly changes the operation mode of a specific agent and selectively transmits a candidate list of parent nodes to supply streams to the agent, thereby applying an efficient overlay multicast policy.

2 is an exemplary diagram for explaining an operation mode of an agent according to an embodiment of the present invention.

As shown in FIG. 2, agents may be classified according to their operation modes according to an embodiment of the present invention. First, agents may be classified into service providers (PPs), relays, and service receivers according to their operation modes. In more detail, the service provider is divided into a single providing mode and a multiple providing mode, and the service receiver is divided into a single receiving mode and a receiving relay mode.

Looking at the rough behavior and constraints of each agent by operation mode, first, an agent in a single mode (PP mode) does not have an input stream channel and has one output stream channel. Send only to the agent. That is, the agent in the single provision mode cannot play the role of a stream server in a mode of transmitting one broadcast stream. Broadcast data, that is, one transmission stream per program is delivered to the agent in the relay mode.

The agent in the multi-provision mode (PP-SVR mode) does not have an input stream channel like the single provision mode (PP mode), and has a plurality of output stream channels. This is useful when the performance of a broadcast platform is not high or a minimum broadcast environment is required. In the present embodiment, the multi-provision mode agent may transmit a broadcast to the relay mode agent and the agent in the reception relay mode.

The relay mode agent is a general distributed stream server resource used for an IPTV broadcasting media platform and is installed in a network according to required stream availability. Agents in relay mode are configurators of Content Delivery Networks (CDN), which are distributed on the network regardless of content, to distribute server traffic and to support overlay multicast without multicast addressing. The relay mode agent has a plurality of input stream channels and a plurality of output stream channels, where the number of input stream channels and output streams varies according to network bandwidth and system capability. Agents in relay mode are allowed to send / receive media with agents in other modes by default.

The agent in a single receive mode (client) is a simple client that does not allow content sharing, only one input stream channel and no output channel stream. The broadcast content stream may be received from an agent in the relay mode.

An agent in client-peer mode has one input stream channel and multiple output stream channels. In this case, the number of output streams may be determined through measurement. The agent in the receiving relay mode has a function in which a single receiving mode and a relay mode are combined. In other words, as a client in a single receive mode, media can be shared with other systems, and the media can be received from an agent in multi-provision mode or a relay mode, and sent to another receive relay mode agent or a single receive mode agent. Can be. However, the present invention is not limited thereto and may be transmitted to a relay mode agent. Therefore, it can be used in the form of P2P that can maximize availability with minimum relay mode resources by a client-peer mode agent.

On the other hand, as can be seen in Figure 2, the transport tree management apparatus is connected to all agents by Transmission Control Protocol (TCP). That is, in the present embodiment, the transport tree management apparatus exchanges messages and XML data of a standard structure with agents belonging to all operating modes through TCP and HyperText Transfer Protocol (HTTP).

In addition, the agents inside the circle indicated by the dotted lines are agents in relay mode, and serve as distributed stream servers as IPTV platforms. According to the tree configured by the transmission tree management apparatus 10, agents perform stream transmission of broadcast content by UDP (User Datagram Protocol).

3 to 5 are exemplary diagrams illustrating a configuration of a transport tree for an agent according to an operation mode according to an embodiment of the present invention.

As shown in FIG. 3, the transport tree management apparatus 10 may perform a tree configuration by reflecting an operation mode of each agent. 4 and 5 are exemplary diagrams of an overlay transmission tree structure formed on an agent in an actual physical network. According to an incentive policy reflecting an operation mode according to an embodiment of the present invention, relay agents in a relay mode are intensively disposed at a medium depth. In addition, the ratio of the agent configured in the single reception mode is high at the end of the tree. The client-peer agent in the receiving relay mode has a lower tree depth, thereby incentivizing the single receiving mode agent for the relative transmission delay. In addition, it is possible to prevent the generation of a skewed tree in which the depth length is infinitely long, thereby improving the performance of the entire transmission tree structure.

6 and 7 are exemplary diagrams for explaining a process of assigning a grade to an agent according to an embodiment of the present invention.

The transport tree management apparatus may assign a class to the agent by assigning a class number within a range defined on the system. First, the transport tree management apparatus checks the network resource information for the agents in the multi-provision mode (PP-SVR), relay mode (Relay), and reception relay mode (Client-Peer) that can be shared to identify the shared resource information. (S700). In the present embodiment, a low rank number is generally assigned to an agent in a relay mode (Relay) that shares many resources regardless of the content type. For example, when the total number of classes defined in the system is 20, the class number is expressed as 1 to 20 for each class, and the relay mode agent may be assigned a rating between 5 and 10 depending on the agent capability. .

In this case, the grade is determined according to the number of input / output stream channels of the corresponding agent. The transport tree management apparatus may determine the number of input / output stream channels of each agent according to the information reported from the agent when the program is executed and the network resource measurement value (S710). In this embodiment, the larger the number of output stream channels, the lower the class number is assigned.

 In addition, it is determined by further reflecting the content layering group number to be described later. In addition, in the layered content (video 0 => movie 1 => action 2), the higher the sharing range, that is, the lower the hierarchy number, the lower rank number is assigned. That is, the relay mode agent determined to the 7-9 level by the network and the agent itself specification may be assigned a level number 7 reflecting the information on the content sharing range. In this case, the content may be registered content for providing a broadcast (S720), shared content for relaying (S722), or selected content (S724) according to a reception request.

The transport tree management apparatus assigns different grades to agents in the system by reflecting the obtained conditions (S730). After that, the tree is configured by reflecting the grade information granted to the agents (S740). Accordingly, in applying an incentive overlay tree configuration algorithm, an optimal algorithm that is more performance-oriented than a tree structure structure according to an operation mode may be calculated. That is, by assigning different grades to agents in the system according to resource sharing capability such as network, system resources, and error frequency and reflecting this grade information in the tree construction, it is possible to implement different positions in the tree to reflect more practical conditions. It is possible.

In addition, as shown in FIG. 7, the rating range is determined by reflecting the network resource information S800 of the agent and the operation mode S820 of the agent, and the hierarchical level information S810 of the provided content is hashed. A rank number is assigned to the agent by combining using a function (S830). In this case, as described above, data is transmitted from the agent set to a low grade number to the agent set to a high grade.

8 is an exemplary tree configuration reflecting content contents provided according to a rating. The relay mode agent is reflected in the data transmission structure on the overlay multicast according to the content content. In addition, the user may configure an environment in which the user receives the content of the classification using the relay mode agent, and may reflect the content classification information in the transmission tree configuration. In other words, the grade of the agent is determined by a combination of hierarchical information according to the content type and the capability of the agent. For example, an agent capable of relaying all types of broadcast content is assigned a rating number 1, and an agent capable of relaying only one TV or UCC among the broadcast contents is assigned a rating number 2. Also, among the cases where only movies or sports can be relayed in the TV and only those movies and sports in the UCC can be relayed, it is reflected when determining the rating number. That is, as shown in FIG. 8, the broadcast content type is reflected in the transmission tree configuration.

9 is an exemplary diagram for explaining a process of restricting a parent node list according to an embodiment of the present invention.

In this embodiment, in constructing the transmission tree by reflecting the grade information assigned to each agent, the lower the class number, the higher the degree of resource sharing. In other words, the agent having a low rank number has a high degree of sharing and can provide a lot of system resources, which is an agent in a relay mode installed by an IPTV provider. Since low-grade agents have a high degree of resource sharing, the number of input stream channels and output stream channels is also large.

That is, the lowest rank number is set because the agent in single serving mode (PP) is a content provider. The rank number is increased in the order of the agent in the multi-provision mode (PP-SVR), the agent in the relay mode (Relay), the agent in the reception relay mode (Client-peer), and the agent in the single reception mode (Client). However, at this time, the rank number order of the relay mode (relay) agent and the receiving relay mode (client-peer) agent may be changed by the sharing condition of the corresponding content. In addition, there is sufficient space of graded regions, and the grade intervals and order in the corresponding regions may be variously applied according to the range of shared content layers and system resources.

Meanwhile, the grade information assigned to each agent may be used as a comparison value when determining transmission / reception rights, parent node, and relay node of each agent when constructing the overlay tree. By using this, agents sharing a lot of resources are located at the upper depth in the transmission tree. On the other hand, less shared nodes are located at the end of the lower tree, which has a relatively high relative transmission delay (RDP) from the source.

Accordingly, considering that the individualized nodes without sharing statistically have a large number of tree departures and changes, the tree recovery performance, which is an important aspect of overlay multicast, can be improved. That is, the performance of the overlay tree can be improved.

In this embodiment, when a new agent occurs, the new agent must be given a rating. At this time, the candidate list of the parent node to receive the content is limited according to the rating information given to the new agent.

In detail, as shown in FIG. 9, for example, an agent having Level 1 having a class number of 1 is shareable to all nodes. Also, a Level 2 agent with a class number of 2 may be shared with an agent having the same or greater number as its class number. That is, in the case of an agent of Level1, the Agents of Level1, Level2, Level3, ... are alliance nodes. In this case, an agent that can be selected as a parent node, that is, a group of nodes is called an alliance node. In addition, in the case of Agent at Level 2, the Agents at Level 2, Level 3,... Except for Agent at Level 1 are allied nodes.

That is, a node equal to or higher than its own rank number is included in the candidate list of the parent node. According to such a node differentiation policy, the above-described overlay performance effect can be seen, and a transmission tree can be configured by reflecting content contents.

10 is an exemplary diagram for explaining a tree recovery process according to an embodiment of the present invention.

First, if a client-peer agent, or node 3, leaves the transport tree while it is relaying streams for another single client, that is, agents 5 and 6, it leaves without a special recovery policy. Create a candidate list of parent nodes for more than one node depth. In addition, the transmission tree may be restored by receiving the stream through the node selected by the node to be recovered and transmitting the stream.

The difference from the occurrence of a new node is that in preparing the parent node list, a candidate list is created for nodes corresponding to a depth greater than or equal to the depth at which node detachment occurs in order to maintain the aforementioned incentive policy. Also, as seen in node 6 after the recovery, the depth information is not newly updated in the tree.

This is a way to avoid another break in the link once restored, so that the tree transport link group in which the break occurs has more tree depth values than the actual physical relay stage. That is, in the present invention which proposes the depth of the tree, it is possible to reduce the frequency of connection of the new node and provide an incentive to the transmission delay. As a result, it is possible to minimize the involvement of another departure in the node group where the departure once occurred.

11 is a flowchart illustrating a tree configuration method according to an embodiment of the present invention.

First, agent information is obtained from each agent in the system, and the operation mode thereof is determined (S200). In this case, the agent information includes at least some of an IP address, port information, input stream channel information, output stream channel information, and bandwidth information of the agent. However, it is not limited thereto. Based on the agent information, the service is divided into a service provider (PP), a relay, and a service receiver (client) for each operation mode of the corresponding agent. In more detail, the service provider may be divided into a single provision mode and a multiple provision mode, and the service receiver may be further divided into a single reception mode and a reception relay mode according to a resource sharing capability, a user's intention to provide a service, or a content sharing policy.

Then, the grade range is allocated to the operation mode of the agent (S210). Then, a grade is assigned to each agent (S220). At this time, according to the operation mode of the agent, it is preferable that the class is allocated within the assigned class range. In addition, the scope of sharing the broadcast content relayed or provided to the corresponding agent is identified, and the rating is further reflected by this information.

In addition, by obtaining agent information from time to time from the agents, it is monitored whether the operation mode of the corresponding agent is changed (S236). If the operation mode is changed, it is desirable to reflect the change (S235), and accordingly, reassign the grade for the corresponding agent.

In operation S240, a transmission tree for broadcasting content transmission is configured in the system by reflecting the grade information assigned to each agent.

12 is a flowchart illustrating a data flow between a transport tree management apparatus and agents according to an embodiment of the present invention.

First, the PP mode agent transmits agent information (S300). At this time, the agent information is transmitted through TCP and includes IP information, port information, input / output stream channel information, and the like. In addition, the agent information reflects the purpose of the agent, system and network measurement results, and characteristics of broadcast contents to be transmitted. The transport tree management apparatus then determines an operation mode of the corresponding agent from the received agent information and assigns a class. The transport tree management apparatus stores the received agent information in a database.

The transport tree management apparatus generates and provides a candidate node list reflecting mode information and grade information of the agent (S310). Then, the agent measures the communication sensitivity with the agents included in the candidate node list (S320), and selects the agent having the optimal measured value as the relay node. Then, the selected node information is provided to the transmission tree management apparatus (S325). The transport tree management apparatus generates tree configuration information by reflecting the received selected node information and provides the generated tree configuration information to the agent (S330, S335). Then, the PP mode agent, which is a service providing mode, selects a relay mode agent based on the tree configuration information obtained from the transport tree management apparatus to form a UDP STREAM channel for providing content.

In addition, agent information is received from a client mode agent (S340). The transport tree management apparatus grasps the class information of the reception mode agent and provides a parent node candidate list reflecting the information (S350). In this case, it is preferable that the transport tree management apparatus generates the candidate list of the parent nodes differently according to the current agent and the transport tree state. Then, the reception mode agent also measures the communication sensitivity and resource sharing capability with the agents included in the parent node list, and selects the agent having the optimal measurement as the parent node (S360). The agent provides the measurement result to the transmission tree management apparatus (S365), and the transmission tree management apparatus transmits tree configuration information to the selected parent node and the reception mode agent (S370 and S375). Then, the reception mode agent may form a UDP STREAM channel for receiving broadcast content through the selected relay mode agent.

13 is a flowchart illustrating in detail a process of constructing a transmission tree according to an embodiment of the present invention.

First, the transport tree management apparatus may receive a broadcast registration request from the service providing mode agent (S400), or may receive a broadcast receiving request from the service receiving mode agent (S402).

When a broadcast registration request or a broadcast reception request is received, candidate nodes are searched according to resource sharing capability and a candidate list is generated (S410). For example, among the agents in the currently registered system, an agent having sufficient bandwidth in the corresponding broadcast content and an input channel stream may be searched and designated as a candidate node.

In operation S420, the class information of the found candidate nodes is identified and filtered according to the grade information. By comparing the ranks of the candidate nodes with the ranks of the agents that transmitted the broadcast registration request or the broadcast reception request, the candidate nodes included in the candidate list are filtered. For example, a parent node of an agent that has transmitted a broadcast reception request and selects agents that are greater than or equal to the class of the agent that has transmitted the broadcast reception request.

Thereafter, the filtered candidate list is provided to the agent that transmits the broadcast registration request or the broadcast reception request (S430). In this case, a measurement command is further transmitted to measure communication status with corresponding candidate nodes.

Then, the selected node information is acquired according to the measurement result from the agent (S440). When a broadcast registration request is received, a message is transmitted to an agent that transmitted the broadcast registration request to provide broadcast content to the selected node (S450).

On the other hand, if a broadcast reception request is received, it is determined whether the selected node is receiving the corresponding broadcast content (S460). If the selected node receives the corresponding broadcast content, it instructs the selected node to transmit the broadcast stream to the agent that has transmitted the broadcast reception request (S470).

If the selected node does not receive the corresponding broadcast content, the agents receiving the corresponding broadcast content are identified (S480). At this time, it is preferable to filter the candidate list by comparing the rank with the selected node that does not receive the corresponding broadcast content. The result is then sent to the selected node to select the parent node of the selected node. That is, when the selected node does not receive the corresponding broadcast content, the transmission tree is configured to be further selected by relaying the parent node of the selected node. At this time, by constructing the tree by comparing the ranks of the agents, the tree can be configured to be located at the upper depth of the transmission tree as the size of the wide media area, the high node resources, and the shared resources increases.

On the other hand, the transport tree management apparatus may receive a connection request from an agent that wants to newly access the tree (S405). Then, the transport tree management apparatus receives the agent information, grasps the information of the agent, and registers the agent (S408). Then, the operation mode of the agent requesting the connection is identified and a grade is assigned. The transport tree management apparatus may configure a transport tree by providing a parent node candidate list based on the agent's rating information, obtaining a selected parent node from the agent, and providing tree configuration information to be connected with the parent node. .

On the other hand, the above-described transmission tree configuration method can be created by a computer program. The program may also be embodied by being stored in a computer readable media and being read and executed by a computer. The storage medium includes a magnetic recording medium, an optical recording medium and the like.

So far I looked at the preferred embodiments of the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is shown in the claims, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

1 is a block diagram showing the configuration of a transport tree management apparatus according to an embodiment of the present invention;

2 is an exemplary diagram for explaining an operation mode of an agent according to an embodiment of the present invention;

3 to 5 are exemplary diagrams illustrating a configuration of a transport tree for an agent according to an operation mode according to an embodiment of the present invention;

6 and 7 are exemplary diagrams for explaining a process of assigning a grade to an agent according to an embodiment of the present invention;

8 is an exemplary tree configuration reflecting content contents provided according to a rating;

9 is an exemplary diagram for explaining a process of restricting a parent node list according to an embodiment of the present invention;

10 is an exemplary diagram for explaining a tree recovery process according to an embodiment of the present invention;

11 is a flowchart of a tree construction method according to an embodiment of the present invention;

12 is a flowchart illustrating a data flow between an apparatus for managing a transport tree and agents according to an embodiment of the present invention;

13 is a flowchart illustrating in detail a process of constructing a transmission tree according to an embodiment of the present invention.

Claims (10)

In the overlay multicast IPTV system including at least one agent, a method for configuring a transport tree between the agents, Identifying an operation mode of the agent; A rating step of assigning a rating to the agent by reflecting the identified operation mode of the agent; And And a tree constructing step of constructing a transfer tree between the agents based on the assigned grade information. The method of claim 1, The grading step, And assigning a rating to each agent by reflecting the resource sharing capability of the agent. The method of claim 2, And the rating step assigns a rating to each agent in consideration of the number of input stream channels and the number of output stream channels of each agent or the hierarchical information of the provided broadcast content. The method of claim 1, Allocating a rating range to be assigned to each operation mode section for the operation mode information before the rating step; And the rating step assigns a rating within the assigned rating range for each operation mode of the agent. The method of claim 1, The operating mode of the agent is a service providing mode including a single serving mode having one output stream channel and a multiple serving mode having a plurality of output stream channels, and a single receiving mode having one input stream channel and no output stream channel. And a service receiver mode including a reception relay mode for outputting broadcast content input through one input stream channel to a plurality of output stream channels, and the service providing mode agent including a plurality of input channel streams and a plurality of output channel streams. And a relay mode for relaying broadcast content transmission between the service reception mode agent and the service reception mode agent. The method of claim 1, wherein after the step of identifying the operation mode, Monitoring the network environment performance or the agent operation performance of the system; And And identifying and changing the operation mode of the agent according to the monitoring result. The method of claim 1, wherein the step of constructing a transport tree, Receiving a broadcast registration request or a broadcast reception request from the agent; Reflecting the grade information of the agent according to the received request, generating a parent node candidate list necessary for constructing a transmission tree, and providing the generated candidate node list to the agent; And And constructing a transmission tree by acquiring selected parent node information among the provided parent node candidate lists from the agent. The method of claim 1, wherein the step of constructing a transport tree, Receiving a connection request from a registration agent; Identifying and ranking an operation mode of the registration agent; Reflecting the grade information of the registration agent according to the received request, generating a parent node candidate list necessary for constructing a transmission tree and providing the registration list to the registration agent; And And constructing a transmission tree by acquiring selected parent node information among the provided parent node candidate lists from the registration agent. A transport tree management apparatus for managing a transport tree between agents in an overlay multicast type IPTV system including at least one agent, An information receiver configured to receive agent information from the agent; An operation mode determining unit configured to determine an operation mode of the agent based on the received information; A class allocator configured to assign a class to the agent by reflecting an operation mode of the agent identified by the operation mode determiner; And And a tree constructing unit for constructing a transmission tree between the agents based on the assigned grade information. The method of claim 9, When receiving a broadcast registration request or a broadcast reception request from the agent, the list providing unit for generating a candidate node list based on the rating information of the agent to provide to the agent; And the tree constructing unit obtains selected node information from the provided candidate node list from the agent, and configures a transmission tree by reflecting the obtained information.

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