KR100765321B1 - Video on demand system and method for guaranteeing quality of service - Google Patents

Abstract

According to the present invention, when a VoD service request message is transmitted from a client, an available bandwidth capable of providing a VoD service requested by the client by checking the bandwidth on the virtual path between the client and the VoD server providing the VoD service requested by the client. The present invention relates to a VOD system requesting a VoD service by transmitting a VoD service request message to a VoD server.

Description

VIDEO ON DEMAND SYSTEM AND METHOD FOR GUARANTEEING QUALITY OF SERVICE}

1 is a diagram illustrating a configuration of a general VoD system.

2 illustrates a configuration of a VoD system that provides guaranteed QoS in accordance with the present invention.

3 is a diagram illustrating an example of a VoD service processing process when there is available bandwidth in a centralized control network.

4 is a diagram illustrating an example of a VoD service processing process when there is no available bandwidth in a centralized control network.

5 is a diagram illustrating a process of providing a guaranteed QOS in a VOD system according to the present invention.

Explanation of symbols on the main parts of the drawings

100: VoD terminal 200: router

300: CDS Web Server 400: Bandwidth Check Server

410: call control manager 420: path manager

430: Service Manager 440: Router Selection Manager

450: Resource Manager 500: VoD Server

The present invention relates to a VOD system and method for providing a guaranteed QOS.

Video on Demand (hereinafter referred to as VoD) is one of the interactive TVs that has taken the current one-way TV to the next level and provides various multimedia information such as movies in real time through a general telephone line. Say service. In other words, the program is selected according to the needs of the subscriber and the service is provided.

In other words, it is a two-way service that can use the desired contents at the desired time according to the subscriber's request, instead of receiving the program unilaterally from the existing public network broadcasting or cable TV. Method provides play, stop, pause, fast forward, fast rewind, and playback at any location.

This VoD system is composed of VoD terminal, VoD server, and VoD delivery network. VoD terminal is largely equipped with a set-top box on an existing TV and a method of using multimedia ITV (Open TV), a TV having a multimedia service function. And a method of using a personal PC.

And, video server (VoD server) is a core platform of VoD service and is equipped with VoD service related software. It is a function that converts existing video program into digital compressed video signal, economical and efficient storage method, and user It includes the ability to provide on-demand programs on demand and other functions necessary to manage service operations such as billing and monitoring.

In addition, the VoD communication network can use a telephone network, a CATV network, a communication-only network, and the most basic form of the method is through an existing telephone network using ADSL technology, Asynchronous Transfer Mode (ATM) and Asymmetric Digital Subscribe Line (ADSL) technology. The method of mixing and the ATM method through a dedicated network such as a coaxial cable or an optical cable.

However, in the conventional VoD system structure, it is difficult to receive quality guarantee for the VoD service requested by the VoD terminal. This is because, if the bandwidth for the user-selected content is free on the network, the service can be provided. If the bandwidth is not available, the bandwidth is insufficient. Therefore, there is a need for a VoD system capable of providing guaranteed QoS (guaranteed QoS) for user-selected content.

Accordingly, an object of the present invention is to solve the above problems and to guarantee the QoS of the requested VoD service by checking the bandwidth for the VoD service requested by the client in advance in the delivery network QoS structure of the centralized control method. The present invention provides a VOD system and a method for providing a guaranteed QOS.

According to an aspect of a multimedia system for providing a guaranteed QOS according to the present invention for achieving the above object, when a multimedia service request message is transmitted from a client, the bandwidth between the client and the VoD server providing the multimedia service And a multimedia service relay unit for transmitting the multimedia service request message to the multimedia server when there is an available bandwidth for providing the multimedia service requested from the client.

The multimedia service request message includes a bandwidth of a multimedia service requested from the client, a source IP address of the client, a destination IP address of the multimedia server, and a service requested from the client. It includes at least one of the class information indicating the type of.

The multimedia service relay unit checks the bandwidth on the virtual path between the client and the multimedia server, and if there is no available bandwidth to provide the multimedia service requested from the client, the multimedia service unavailable message to the client. Send it.

The multimedia service relay unit includes a call control manager for controlling a call by analyzing a multimedia service request message transmitted from the client, a service manager for checking a type of a service requested from the client and notifying the call control manager; A virtual path manager configured to store virtual path information between the IP address of the client and the IP address of the multimedia server transmitted from the call control manager when it is determined that the type of service requested from the client is a multimedia service; The call control management of the presence or absence of the available bandwidth by checking the bandwidth on the virtual path selected by the virtual path selection unit and the virtual path selection unit for selecting a virtual path between the IP address of the client and the IP address of the multimedia server stored in the management unit It includes a resource manager for advice to.

The virtual path manager changes and updates the virtual path information stored in the virtual path information database when a network failure occurs while all the virtual path information about the network is stored in the virtual path information database in advance.

The resource manager updates the resource information stored in the resource information database whenever the resource information is changed in a state in which resource information of each node of the network is previously stored in the resource information database.

When the call control manager checks the bandwidth on the virtual path selected by the virtual path selector and there is an available bandwidth, the call control manager transmits the multimedia service response message to the client and transmits the multimedia service request message to the multimedia server. do.

The multimedia service response message is a unique Call ID value given by the call control manager.

The call control manager transmits a multimedia service error message to the client when there is no available bandwidth as a result of checking the bandwidth on the virtual path selected by the virtual path selector.

The multimedia service error message includes at least one of a unique Call ID value assigned by the call control manager, an error code indicating that the multimedia service cannot be reserved, and error string information indicating that the multimedia service bandwidth is insufficient. Contains one piece of information.

Meanwhile, according to an aspect of the method for providing the guaranteed QOS in the multimedia system according to the present invention for achieving the above object, when the multimedia service request message is transmitted from the client, the multimedia providing the multimedia service with the client Checking the bandwidth between the servers and transmitting the multimedia service request message to the multimedia server when there is available bandwidth to provide the requested multimedia service from the client as a result of checking the bandwidth. Include.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, detailed descriptions of preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that reference numerals and like elements among the drawings are denoted by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a diagram illustrating a configuration of a general VoD system.

As shown in FIG. 1, first, a user uses a VoD terminal (Client PC or STB, 10) to provide contents through a router 20 to provide contents through a router 20. 30).

Thereafter, when the user selects content to be serviced from the content provided from the CDS web server 30, the CDS web server 30 sends the address of the VoD server 40 for the content selected by the user to the VoD terminal 10. ) Will be provided.

Accordingly, the VoD terminal 10 provided with the address of the VoD server 40 from the CDS web server 30 requests a service from the corresponding VoD server 40.

Accordingly, the VoD server 40 which has received the service request provides the VoD service to the VoD terminal 10 which has requested the service.

FIG. 2 is a diagram illustrating a configuration of a VoD system that provides guaranteed QoS according to the present invention, and illustrates a VoD service in a voice and multimedia over centralized control-based transport network structure.

As shown in FIG. 2, the VoD system of the present invention includes a VoD terminal 100 constituting an access network, a CDS web server constituting a router 200, and a centralized control network. 300, a bandwidth check server 400, and a VoD server 500.

The VoD terminal 100 is a terminal for receiving VoD service and accesses the CDS web server 300 through the router 200 and selects content to be serviced from contents provided from the CDS web server 300. .

The CDS web server 300 requests the VoD service to the bandwidth check server 400 when the user selects content to be serviced. In particular, when requesting a VoD service, information about bandwidth (BW), source address, source address, destination address, and type of service is requested to the bandwidth check server 400. Is sent.

When the centralized control platform (CCM) 400 receives the VoD service from the CDS web server 300, the bandwidth check server 400 checks the bandwidth between the source address and the destination address.

As a result of the check, if there is no available bandwidth, the bandwidth check server 400 transmits a message indicating that VoD service is impossible to the CDS web server 300, and the CDS web server 300 transmits the VoD terminal 100 through the router 200. ) Will send the VoD service unavailable message.

Accordingly, the user requesting the VoD service recognizes that the VoD service is impossible through the VoD terminal 100.

However, when the bandwidth check server 400 checks the bandwidth between the source address and the destination address, if there is available bandwidth, the bandwidth of the VoD service requested from the CDS web server 300 ( The VoD service request message including the BW, the source address, the destination address, and the type of service is transmitted to the VoD server 500.

The VoD server 500 provides information about the bandwidth (BW), the source address, the destination address, and the type of service of the VoD service transmitted from the bandwidth check server 400. After confirming, the requested VoD service is transmitted to the VoD terminal 100 through the router 200.

That is, the VoD service method of the present invention provides QoS for the centralized virtual path through the bandwidth check server, unlike the conventional VoD system structure in which the bandwidth for the requested service cannot be guaranteed according to network conditions. You can do it.

In other words, by selecting an available logical path in the centralized control network and continuously updating the resource information for the virtual path, the bandwidth is guaranteed if there is available bandwidth for the service interval requested by the user. Thus, a more reliable service can be provided. In this case, the logical path means MPLS LSP in the MPLS network and VP in the IP network.

FIG. 3 is a diagram illustrating an example of a VoD service processing process in a centralized control-based transport network structure according to the configuration of the bandwidth check server of FIG. 2.

As shown in FIG. 3, first, a user of the VoD terminal 100 accesses a CDS web server 300 belonging to a centralized control type delivery network through a router of an access network. The VoD content to be serviced is selected from various contents provided from the web server 300.

Accordingly, after the CDS web server 300 performs an authentication procedure for the user, the CDS web server 300 generates a VoD request message (NRCP-like message) and transmits it to the bandwidth check server 400 of the present invention. In this case, as described above, the transmitted VoD request message includes a bandwidth parameter indicating the bandwidth of the VoD service requested from the user terminal and a source IP address indicating the IP address of the user terminal requesting the VoD service. Address), a destination IP address indicating an IP address of a VoD server providing a VoD service requested from a user terminal, and information on a class parameter indicating a type of a requested service. Lose.

The bandwidth check server 400 processes the VoD request message transmitted from the CDS web server 300.

That is, the bandwidth check server 400 includes a call control manager (CCM) 410, a path manager (PM) 420, a service manager (SM) 430, A router selection manager (RSM) 440 and a resource manager RM 450 are included.

The call control manager (CCM) 410 receives and analyzes a VoD request message (Network Resource Control Protocol-like: NRCP-like message) transmitted from the CDS web server 300.

That is, the service manager (SM) 430 transmits information about a class indicating the type of service included in the VoD request message to confirm the type of service.

If it is confirmed that the requested service type is a VoD service, the call control manager (CCM) 410 transmits the information on the source IP address (SA) and the destination IP address (DA) included in the VoD request message. (PM) 420 is delivered.

The path manager (PM) 420 receives information about the source IP address (SA) and the destination IP address (DA) transmitted from the call control manager (CCM) 410 and the router selection manager (RSM) 440. Will be sent to.

In particular, the path manager (PM) 420 grasps virtual path information of the delivery network in advance and stores it in a DB. The virtual path information may be changed when a network failure occurs. The changed information is updated in the DB.

The router selection manager (RSM) 440 selects a virtual path (VP) between the SA and the DA through the virtual path information DB of the path manager (PM) 420 and then selects the resource through the resource manager (RM) 450. The presence of bandwidth on the virtual path (VP) is checked.

The resource manager (RM) 450 grasps the resource information of each node of the delivery network in advance and records it in the resource information DB at an initial stage of operation, and updates the resource information DB whenever the resource information is changed.

That is, the resource manager (RM) 450 checks the available bandwidth on the MPLS LSP if the centralized control network is composed of MPLS, and if the delivery network is composed of IP, it is available through the virtual path (VP) in the IP network. You will be checking your bandwidth.

Therefore, when the delivery network is an IP network, the path manager (PM) 420 may have virtual path information between all user terminals connected to the IP network and the VoD server in advance.

That is, the resource manager (RM) 450 notifies the call control manager (CCM) 410 that the available bandwidth exists if there is available bandwidth as a result of checking whether the bandwidth exists on the selected virtual path, and the virtual path (VP) currently in service. Will update its resources.

Accordingly, the call control manager (CCM) 410 transmits {Call ID}, which is a VoD response message for the VoD request message, to the CDS web server 300, and then the CDS web server 300 to the VoD server 500. The VoD request message received from the server is transmitted as it is. Here, Call ID means a unique ID value assigned by the call control manager (CCM) 410.

The VoD server 500 checks the VoD request message received from the call control manager (CCM) 410 and provides the VoD service to the corresponding user terminal that has requested the VoD service through a plurality of network elements (NEs) 610, 620, and 630. By providing it, it is possible to provide a QoS-guaranteed VoD service through the guaranteed bandwidth between the VoD server providing the VoD service and the VoD terminal.

FIG. 4 is a diagram illustrating another example of a process of processing a VoD service when an available bandwidth is insufficient in a centralized control-based transport network structure.

As shown in FIG. 4, first, a user of the VoD terminal 100 accesses a CDS web server 300 belonging to a centralized control type delivery network through a router of an access network. The VoD content to be serviced is selected from various contents provided from the web server 300.

Accordingly, after the CDS web server 300 performs an authentication procedure for the user, the CDS web server 300 generates a VoD request message (NRCP-like message) and transmits it to the bandwidth check server 400 of the present invention. In this case, as described above, the transmitted VoD request message includes a bandwidth parameter indicating a bandwidth of the VoD service requested from the user terminal and a source IP address indicating an IP address of the user terminal requesting the VoD service. ), A destination IP address indicating an IP address of a VoD server providing a VoD service requested from a user terminal, and information about a class parameter indicating a type of the requested service. .

The bandwidth check server 400 processes the VoD request message transmitted from the CDS web server 300.

That is, the Call Control Manager (CCM) 410 of the bandwidth check server 400 receives a VoD request message (Network Resource Control Protocol-like: NRCP-like message) transmitted from the CDS web server 300. Analyze by

That is, the service manager (SM) 430 transmits information about a class indicating the type of service included in the VoD request message to confirm the type of service.

If it is confirmed that the type of service is a VoD service, the call control manager (CCM) 410 sends information about the source IP address SA and the destination IP address DA included in the VoD request message to the path manager PM. 420).

The path manager (PM) 420 forwards the information about the source IP address SA and the destination IP address DA, which are transmitted from the call control manager (CCM) 410, to the router selection manager (RSM) 440. do.

In particular, the path manager (PM) 420 grasps virtual path information of the delivery network in advance and stores it in a DB. The virtual path information may be changed when a network failure occurs. The changed information is updated in the DB.

The router selection manager (RSM) 440 selects a virtual path (VP) between the SA and the DA through the virtual path information DB of the path manager (PM) 420 and then selects the resource through the resource manager (RM) 450. The presence of bandwidth on the virtual path (VP) is checked.

The resource manager (RM) 450 grasps the resource information of each node of the delivery network in advance and records it in the resource information DB at an initial stage of operation, and updates the resource information DB whenever the resource information is changed.

That is, the resource manager (RM) 450 checks the available bandwidth on the MPLS LSP if the centralized control network is composed of MPLS, and if the delivery network is composed of IP, it is available through the virtual path (VP) in the IP network. You will be checking your bandwidth.

Therefore, when the delivery network is an IP network, the path manager (PM) 420 may have virtual path information between all user terminals connected to the IP network and the VoD server in advance.

That is, the resource manager (RM) 450 notifies the call control manager (CCM) 410 that there is no available bandwidth if there is no available bandwidth as a result of checking the presence or absence of the bandwidth on the selected virtual path, and the virtual path (VP) currently in service. Will update its resources.

Accordingly, the call control manager (CCM) 410 transmits a VoD response message indicating an error to the VoD request message to the CDS web server 300. Here, the VoD response message indicating an error includes information such as {Call ID, Error code = Reservation denied, Error string = Scarce BW}.

That is, Call ID means a unique ID value assigned by the call control manager (CCM) 410, Error code = Reservation denied indicates that the reservation is impossible, Error string = Scarce BW indicates that the bandwidth is insufficient.

Accordingly, the user who is connected to the CDS web server 300 can recognize that there is no available bandwidth for the requested VoD service and thus cannot receive the requested VoD service.

5 is a diagram illustrating a process of providing a guaranteed QOS in the VOD system according to the present invention.

As shown in FIG. 5, a user of a VoD terminal is provided from a CDS web server by accessing a CDS web server belonging to a centralized control delivery network through a router of an access network (S10). The user selects the VoD content to be serviced from various contents (S20).

Accordingly, after the CDS web server performs an authentication procedure for the user, the CDS web server generates a VoD request message (NRCP-like message) and transmits it to the bandwidth check server (S30).

In this case, as described above, the transmitted VoD request message includes a bandwidth parameter indicating a bandwidth of the VoD service requested from the user terminal and a source IP address indicating an IP address of the user terminal requesting the VoD service. ), A destination IP address indicating an IP address of a VoD server providing a VoD service requested from a user terminal, and information about a class parameter indicating a type of the requested service. .

Accordingly, the bandwidth check server processes the VoD request message sent from the CDS web server.

That is, the call control manager (CCM) receives and analyzes a VoD request message (Network Resource Control Protocol-like: NRCP-like message) transmitted from the CDS web server.

That is, the type of service is confirmed by transmitting information on a class indicating the type of service included in the VoD request message to the service manager SM (S40).

If it is confirmed that the type of service is a VoD service, the call control manager (CCM) transmits information on the source IP address (SA) and the destination IP address (DA) included in the VoD request message to the path manager (PM). Done.

Accordingly, the path manager PM transmits the information about the source IP address SA and the destination IP address DA transmitted from the call control manager CCM to the router selection manager RSM (S50).

Subsequently, the router selection manager RSM selects the virtual path VP between the SA and the DA through the virtual path information DB of the path manager PM (S60), and then selects the virtual path selected through the resource manager RM (S60). VP) checks the presence or absence of bandwidth on the controller (S70).

As a result of the check, when there is available bandwidth on the selected virtual path, the resource manager (RM) notifies the call control manager (CCM) that there is available bandwidth, and updates the resources of the virtual path VP currently in service.

Accordingly, the call control manager (CCM) transmits {Call ID}, which is a VoD response message for the VoD request message, to the CDS web server (S80), and then transmits the VoD request message received from the CDS web server to the VoD server as it is. (S90).

Subsequently, the VoD server checks the VoD request message received from the call control manager (CCM) and provides the VoD service to the corresponding user terminal requesting the VoD service through a plurality of network elements (NEs) (S100).

On the other hand, in the process of checking the presence or absence of the bandwidth on the selected virtual path (VP) through the resource manager (RM), if there is no available bandwidth to notify the call control manager (CCM) that there is no available bandwidth, the current service The resource of the virtual path VP that is being updated is updated.

Accordingly, the call control manager (CCM) transmits the VoD error message for the VoD request message to the CDS web server (S110). Here, the VoD error message indicating an error includes information such as {Call ID, Error code = Reservation denied, Error string = Scarce BW}.

Accordingly, the user who is connected to the CDS web server can confirm that there is no available bandwidth for the currently requested VoD service and thus cannot receive the requested VoD service (S120).

In the above, specific preferred embodiments of the present invention have been illustrated and described. However, the present invention is not limited to the above-described embodiment, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention attached to the claims. will be.

According to the present invention, by checking the bandwidth for the VoD service requested by the client in advance to ensure the QoS of the requested VoD service, it can be effectively used in the transmission network structure of the centralized control method that provides services related to mass capacity and multimedia. have.

Claims (27)

In a multimedia system, When the multimedia service request message is transmitted from the client, when there is an available bandwidth to check the bandwidth between the client and the multimedia server providing the multimedia service from the client, the multimedia service request Including a multimedia service relay unit for transmitting a message to the multimedia server, The multimedia service request message includes a bandwidth of a multimedia service requested from the client, a source IP address of the client, a destination IP address of the multimedia server, and a service requested from the client. Multimedia system including at least any one of class information indicating the type of. delete The method of claim 1, The multimedia service relay unit, And checking a bandwidth between the client and the multimedia server, and if there is no bandwidth available to provide the requested multimedia service from the client, transmitting the multimedia service unavailable message to the client. The method of claim 1, The multimedia service relay unit, A call control manager configured to control a call by analyzing a multimedia service request message transmitted from the client; A service manager for checking the type of service requested from the client and notifying the call control manager; A virtual path manager configured to store virtual path information between an IP address of the client and an IP address of the multimedia server transmitted from the call control manager when it is determined that the type of service requested from the client is a multimedia service; A virtual path selector for selecting a virtual path between an IP address of the client and an IP address of the multimedia server stored in the virtual path manager; And And a resource manager which checks the bandwidth on the virtual path selected by the virtual path selector and notifies the call control manager whether there is available bandwidth. The method of claim 4, wherein The virtual path management unit, And updating and changing the virtual path information stored in the virtual path information database when a network failure occurs in a state in which all the virtual path information about the network is previously stored in the virtual path information database. The method of claim 4, wherein The resource management unit, And updating the resource information stored in the resource information database whenever the resource information is changed in a state in which resource information of each node of the network is previously stored in the resource information database. The method of claim 4, wherein The call control management unit, And checking the bandwidth on the virtual path selected by the virtual path selection unit, if there is an available bandwidth, transmitting the multimedia service response message to the client and transmitting the multimedia service request message to the multimedia server. The method of claim 7, wherein The multimedia service response message is a unique call ID value given by the call control manager. The method of claim 4, wherein The call control management unit, And if there is no available bandwidth as a result of checking the bandwidth on the virtual path selected by the virtual path selection unit, transmitting the multimedia service error message to the client. The method of claim 9, The multimedia service error message includes at least one of a unique Call ID value assigned by the call control manager, an error code indicating that the multimedia service cannot be reserved, and error string information indicating that the multimedia service bandwidth is insufficient. Multimedia system containing one information. In a multimedia system, A call control manager configured to control a call by analyzing a multimedia service request message transmitted from a client; A service manager for checking the type of service requested from the client and notifying the call control manager; A virtual path manager configured to store virtual path information between an IP address of the client and an IP address of the multimedia server transmitted from the call control manager when it is determined that the type of service requested from the client is a multimedia service; A virtual path selector for selecting a virtual path between an IP address of the client and an IP address of the multimedia server stored in the virtual path manager; And And a resource manager which checks the bandwidth on the virtual path selected by the virtual path selector and notifies the call control manager whether there is available bandwidth. The method of claim 11, The virtual path management unit, And updating and changing the virtual path information stored in the virtual path information database when a network failure occurs in a state in which all the virtual path information about the network is previously stored in the virtual path information database. The method of claim 11, The resource management unit, And updating the resource information stored in the resource information database whenever the resource information is changed in a state in which resource information of each node of the network is previously stored in the resource information database. The method of claim 11, The call control management unit, And checking the bandwidth on the virtual path selected by the virtual path selection unit, if there is available bandwidth, transmitting the multimedia service response message to the client and transmitting the multimedia service request message to the multimedia server. The method of claim 14, The multimedia service response message is a unique call ID value given by the call control manager. The method of claim 11, The call control management unit, And if there is no available bandwidth as a result of checking the bandwidth on the virtual path selected by the virtual path selection unit, transmitting the multimedia service error message to the client. The method of claim 16, The multimedia service error message includes at least one of a unique Call ID value assigned by the call control manager, an error code indicating that the multimedia service cannot be reserved, and error string information indicating that the multimedia service bandwidth is insufficient. Multimedia system containing one information. In the method for providing a guaranteed QOS in a multimedia system, When the multimedia service request message is transmitted from the client, checking a bandwidth between the client and the multimedia server providing the multimedia service; Checking the bandwidth, and if there is available bandwidth to provide the multimedia service requested from the client, transmitting the multimedia service request message to the multimedia server, The multimedia service request message includes a bandwidth of a multimedia service requested from the client, a source IP address of the client, a destination IP address of the multimedia server, and a service requested from the client. A method for providing a guaranteed QOS in a multimedia system including at least any one of class information indicating the type of. delete The method of claim 18, As a result of checking the bandwidth between the client and the multimedia server, if there is no available bandwidth to provide the requested multimedia service from the client, the guaranteed QOS in the multimedia system transmitting the message that the multimedia service unavailable to the client How to give it. The method of claim 18, The process of checking the bandwidth, Analyzing a multimedia service request message sent from the client; Checking the type of service requested from the client; If it is determined that the type of service is a multimedia service, storing virtual path information between the IP address of the client and the IP address of the multimedia server; Selecting a virtual path between the stored client's IP address and the multimedia server's IP address; And Checking the bandwidth on the selected virtual path to confirm the presence or absence of available bandwidth. The method of claim 21, The virtual path information provides a guaranteed QOS in a multimedia system that is changed and updated when a network failure occurs. The method of claim 21, A method for providing a guaranteed QOS in a multimedia system for updating pre-stored resource information whenever the resource information on the virtual path is changed. The method of claim 21, The method for providing guaranteed QOS in a multimedia system for transmitting a multimedia service request message to the multimedia server after transmitting a multimedia service response message to the client when there is an available bandwidth as a result of checking the bandwidth on the selected virtual path. . The method of claim 24, The multimedia service response message is a method of providing a guaranteed QOS in the multimedia system is a unique Call ID value. The method of claim 21, And if there is no available bandwidth as a result of checking the bandwidth on the selected virtual path, transmitting the multimedia service error message to the client. The method of claim 26, The multimedia service error message includes at least one of a unique Call ID value, an error code indicating that the multimedia service cannot be reserved, and error string information indicating that the multimedia service bandwidth is insufficient. How to provide guaranteed QOS in the system.

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