KR100592541B1 - multicast web-broadcasting system - Google Patents

Abstract

The present invention relates to a multicast web broadcasting system, and more particularly, to a multicast web broadcasting system using an overlay multicast method. The present invention provides a multicast web broadcasting system having a service server for providing content to be distributed, the multicast agent controlling downloading of the content from the service server and overlaying multicast information of a session to a client, and the multicast. And a session manager for exchanging control signals with an agent and managing the session, and when there is no adjacent multicast agent within a predetermined distance from a first client connected to the service server, the first client as the multicast agent. The second client, which plays a role and is located within a predetermined distance from the first client, registers as a client of a subgroup of the first client. As a result, the content provider can easily announce the created session to allow the client to subscribe, and can efficiently use network resources through web broadcasting through overlay multicast without additional cost such as improving the router.

Overlay Multicast, Multicast, Webcast

Description

Multicast web-broadcasting system

1 is a block diagram of an overlay multicast web broadcasting system according to an embodiment of the present invention;

2 is a flowchart of an overlay multicast webcasting method according to an embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

1: service server 2: multicast agent

3: session manager 4: application registry

5: session search server 6: client

The present invention relates to a multicast web broadcasting system, and more particularly, to a multicast web broadcasting system using an application registry for session discovery and an overlay multicast method.

As the spread of the Internet gradually expands, various services are provided through the Internet. Services for providing movies, broadcasts, etc. to clients through the Internet are expanding and various technologies are being developed.

There are unicast, multicast, and broadcast methods for transmitting data through the Internet.

The unicast method is a method in which one sender transmits data to one receiver, a traffic transmission method of the Internet currently being used, and a point to point transmission method. In the unicast method, since data packets need to be repeatedly transmitted as many as the number of receivers, packets having the same contents may be redundantly transmitted unnecessarily, thereby reducing the efficiency of network resource usage and causing network congestion.

The broadcast method is a method of transmitting data to all hosts existing in a network, and refers to a method of transmitting data to an unspecified number such as a commercial TV or a radio.

The multicast method is a method of transmitting data to all hosts joined to the same group on the Internet. In the multicast method, one data packet is delivered to a group including a plurality of clients, thereby reducing unnecessary duplication and efficiently using network resources.

However, the multicast scheme has not been widely used due to the complexity and difficulty of implementation and the absence of a profit model. The multicast scheme has repeatedly provided current multicast multimedia services by repeatedly using the current unicast transmission scheme.

Multicast transmission methods include IP multicast and overlay multicast.

In the Internet structure, data transmission function is provided at the network layer in OSI layer 7. The IP multicast method is a transmission method proposed by Deering that adds a multicast function to the IP layer among the network layers where the data transmission function is implemented in the Internet structure.

In other words, in the IP multicast scheme, routers distributed in a network form a data transmission tree, and as the multicast packets pass through the tree, the multicast packets are branched to each branch point of the tree. at the point of copying by the router.

The IP multicast scheme is evaluated as the most efficient way to perform group data distribution because packet copying can be minimized in wide-area networks.

However, in order to support the IP multicast method, additional functions need to be added to the router, and there is a problem that a lot of load is required because the state for each group and source must be managed. In addition, the IP multicast method has a disadvantage in that transmission reliability and congestion control are difficult.

The IP multicast method has an advantage of efficiently distributing group data, but it is not widely used due to the above-mentioned disadvantages.

The overlay multicast transmission method is a data transmission method that is evaluated as an alternative to the IP multicast transmission method, and is an transmission method that maintains and manages an efficient overlay for data transmission.

Overlay multicast, also called application layer multicast or relayed multicast, is an application layer that uses unicast-based data and host-based routing. Is a multicast transmission technique for buffering and routing.

In the IP multicast scheme, routing of multicast data occurs at each end-system. Therefore, each end-system of the overlay network copies the data packet and forwards it to another end system so that all participants in the multicast group can receive the multicast packet.

However, this overlay multicast method does not have a protocol for informing information about which source and session exist. In addition, since overlay multicast is a protocol for relaying data at the application layer, a dedicated application must exist for each protocol, and users participating in each multicast group must use the same application. Therefore, there must be a way to distribute the application to users who participate in the group.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multicast web broadcasting system based on an overlay multicasting scheme in which an appropriate client performs a multicast agent function, and discovers which source and session exist and when the client wants to participate in the session. To provide.

The above object is a multicast web broadcasting system having a service server for providing content to be distributed according to the present invention, wherein the content is downloaded from the service server and mediated to a client and controlled to overlay multicast overlay of session information. And a session manager for exchanging control signals with the multicast agent and managing the session, and wherein there is no adjacent multicast agent within a predetermined distance from a first client connected to the service server. A client plays a role as the multicast agent, and a second client located within a predetermined distance from the first client registers as a client of a subgroup of the first client. It can be.

The multicast web broadcasting system further includes an application registry for registering information of the content, and a session search server for searching session information of the content registered in the application registry, wherein the first client transmits the session search server to the session search server. Access to search for the desired session information, if there is no adjacent multicast agent within a predetermined distance may be to download the content from the service server and act as the multicast agent.

The first client preferably downloads the content from the multicast agent when there is an adjacent multicast agent within a predetermined distance, and from the first client when the first client terminates access to the service server. If there is a client of the subgroup receiving the content, it is preferable to select one of the clients of the subgroup to function as the multicast agent.

In this case, the application registry may include a UDDI registry.

1 is a block diagram of an overlay multicast web broadcasting system according to an embodiment of the present invention.

As shown in Fig. 1, the overlay multicast web broadcasting system includes a service server 1, a multicast agent 2, a session manager 3, an application registry 4, a session search server 5, and a client 6 Has

The service server 1 may be composed of a plurality of computer systems that provide contents to be distributed to a user by a service provider.

The multicast agent 2 downloads the content from the service server 1 and transmits the session information to the client by the overlay multicast method.

The session manager 3 exchanges control signals with the multicast agent 2 and manages the session. The session manager 3 is preferably located in the service server 1 and may allow the user computer to take charge of the session manager 3.

The application registry 4 is a registry for registering content provided by the service server 1, and the application registry 4 may use a universal description, discovery, and integration (UDDI) registry.

The session search server 5 searches for session information of the content registered in the application registry 4 and outputs a search result.

As a multicast sender, the content provider must first set a multicast address for each content transport stream and perform a session creation and notification function for multicast transmission.

The content provider creates a session for the content to be distributed and informs the user of the content information about the content. This notification method is preferably using a UDDI registry, and can be notified to other clients through mail notification and advertisement. The recommended method for expressing session information such as session ID, media type, and content information is defined in the SDP (Session Description Protocol) standard document, but in some cases, a modified form of SDP may be possible.

When the content provider registers the content in the UDDI registry and creates a session in which the user can use the content, the user can access the service server 1 at any time and use the content.

2 is a flowchart of an overlay multicast webcasting method according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 and 2.

The client 6 accesses the session search server 5 to obtain information on what session is currently created (S1). The client 6 searches for relevant information of the desired session through the session search server 5 (S2), and the session or content information registered in the plurality of application registries 4 interspersed with the session search server 5. Search for and output to the client 6 (S3).

The client 6 determines whether to join the session based on the known session information and joins the session. When there is a request for a session subscription from the client 6, the session manager 3 determines whether there is a multicast agent 2 adjacent to the client 6 at a predetermined distance (S4).

When there is an adjacent multicast agent 2 within a predetermined distance from the client 6, the client 6 becomes a member of a subgroup receiving content from the multicast agent 2 (S5, S6).

If there is no adjacent multicast agent 2 within a predetermined distance from the client 6, the client 6 may be provided with content from the nearest multicast agent 2 or the service server 1.

It is determined by comparing the distance from which source the content is provided (S7), and downloads the content from the source more favorable for downloading the content (S8, S9).

The client 6 may then function as a new multicast agent 2, and if the client 6 newly joining the session is adjacent to the newly formed multicast agent 2 within a predetermined distance, the new multicast agent 2. It becomes a member of the subgroup of (2) (S10).

In the case of not subscribing to the session of the web broadcasting service server 1 through the session search server 5, the steps S1, S2, and S3 are omitted in FIG. Controlled by (3). In addition, the above-described predetermined distance may be measured in various ways and is a reference distance experimentally predetermined by the service provider based on the time required for data transmission.

Since the multicast agent 2 is performed by the client 6, a new multicast agent 2 is needed when the client 6 leaves the session. The newly selected multicast agent is preferably selected from clients of subgroups of the multicast agent to be destroyed.

On the other hand, if there is no subgroup of extinguished multicast agents, there is no need to select a new multicast agent.

Overlay multicast is a protocol for relaying data in the application layer, so a dedicated application must exist for each protocol, and users participating in each multicast group must use the same application. Therefore, the content to be transmitted from the service server 1 to each multicast agent 2 and the client 6 should include a dedicated application for each protocol and also include information such as video, sound, and game data.

The content is sent directly from the service server 1 to the multicast agent 2, which can copy the packet of content and send it to the client 6 in the subgroup.

Alternatively, the multicast agent 2 has a tree structure forming a mesh, and when the service server 1 transmits the content to the terminal multicast agent 2, the content is the neighboring multicast agent 2. Are sent sequentially. In this mesh-shaped tree structure, the data transmitted to the service server 1 by the multicast agent 2 upstream is transferred to the service server 1 along the mesh.

In order to control the data transmission between the multicast agents (2), the RMCP (Relay Multicast Control Protocol) proposed by the Korea Electronics and Telecommunications Research Institute (ETRI) can be used. The cast transmission method, the IP unicast tunneling method, etc. may be used. The transmission of the application may be transmitted from the service server 1 to the multicast agent 2 and other contents may be transmitted using a mesh.

The broadcast includes content such as over-the-air broadcasting and encompasses an Internet service in which multiple clients can share information such as games and chat.

Although some embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that the embodiments may be modified without departing from the spirit or spirit of the invention. . It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

According to the present invention, the content provider can easily notify the created session to allow the client to subscribe, and can efficiently use network resources through web broadcasting through overlay multicast without additional cost such as improving the router. .

Claims (6)

In the multicast web broadcasting system having a service server for providing content to be distributed, A multicast agent for downloading the content from the service server and controlling the client to overlay and multicast the session information; A session manager for exchanging control signals with the multicast agent and managing the sessions; An application registry for registering information of the content; A session search server for searching session information of the content registered in the application registry; A second client serving as the multicast agent when there is no adjacent multicast agent within a predetermined distance from the first client accessing the service server, and a second located within the predetermined distance from the first client And the client registers as a client of the subgroup of the first client. The method of claim 1, The first client accesses the session search server, searches for desired session information, and downloads the content from the service server and serves as the multicast agent when there is no adjacent multicast agent within a predetermined distance. Multicast Web Broadcasting System. The method according to claim 1 or 2, And the first client downloads the content from the multicast agent when there is an adjacent multicast agent within a predetermined distance. The method of claim 2, And said application registry comprises a UDDI registry. The method according to claim 1 or 2, When the first client terminates access to the service server, if there is a client of the subgroup receiving the content from the first client, one of the clients of the subgroup is selected to function as the multicast agent. Multicast Web Broadcasting System. The method according to claim 1 or 2, The session search server searches for the session information desired by the client and outputs the same to the client.

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