JP5064425B2 - Relay device, relay method and relay processing program for video distribution service providing system - Google Patents

Description

  The present invention provides a service in which quality is guaranteed in a video distribution service provided through a network such as multicast, by efficiently performing a network resource securing process based on the contents of the multicast control request message. The present invention relates to a relay device, a relay method, and a relay processing program of a video distribution service providing system.

  At present, standardization organizations such as TISPAN are discussing a procedure for realizing a multicast service through a management network such as NGN (Next Generation Network) (Non-Patent Document 1 and Non-Patent Document 2). This procedure assumes that the communication terminal processes two protocols, a session control protocol and a multicast control protocol.

  In this case, the communication terminal can use a service with guaranteed service quality by performing network control such as session establishment and securing of network resources using a session control protocol. In addition, the communication terminal can join and leave a multicast group using a multicast control protocol such as MLD (Multicast Listener Discovery) and IGMP (Internet Group Management Protocol).

  On the other hand, many of existing multicast services are provided through existing closed networks. Since existing closed networks do not perform network control such as session establishment or securing network resources, many existing communication terminals do not support session control protocols such as SIP (Session Initiation Protocol). It corresponds only to. Therefore, it is impossible to realize a quality assurance type service combining a session control protocol and a multicast control protocol in a managed network as defined in Non-Patent Document 2 using these existing communication terminals. It is.

  In addition, in the procedure for realizing a multicast service through a managed network, which is being discussed by standardization organizations such as TISPAN, a plurality of multicast streams are bundled as one package (hereinafter referred to as a multicast package) to establish a session or network resource for each package. A method of performing network control such as securing has been studied. The multicast package is a concept of bundling a plurality of multicast streams in accordance with the provided service, content details, and the like. As specific examples, classification based on provided services such as “free package” and “paid basic channel package”, classification based on contents such as “domestic sports package”, “foreign film package”, and the like are assumed.

  On the other hand, in the existing multicast service, it is assumed that a multicast join request / leave request is performed in units of multicast streams. Therefore, when an existing communication terminal used for these services is used, it is impossible to realize control in units of multicast packages as described above.

ETSI TS 183 063 V2.1.0 (2008-06) Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IMS-based IPTV stage 3 specification ETSI TS 185 009 V2.1.1 (2008-07) Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Architecture and reference points of a customer network device for IMS based IPTV services Image Electronics Society 20th VMA Study Group (January 18, 2008), A Study on Realization of Communication Service by Cooperation of Information Appliances, Yoshiki Nishikawa, Goro Inomae, Naoji Matsukawa, Hiroshi Kansenji

  As described above, in a method for realizing a multicast service provided through a managed network such as NGN, which is currently being discussed in a standard organization such as TISPAN, a communication terminal supports a session control protocol in addition to a multicast control protocol. It was necessary to have. However, since many of the communication terminals that are currently widely used support only the multicast control protocol, it has been impossible to use those communication terminals in a managed network.

  The present invention has been made in view of the above circumstances, and a relay device, a relay method, and a relay method for a video distribution service providing system that can use an existing communication terminal that does not support the session control protocol in a management network. An object is to provide a relay processing program.

In order to achieve the above object, the relay device of the video distribution service providing system according to the present invention is configured as follows.
(1) Used in a system that provides a content distribution service of a multicast package as a package in which a plurality of multicast streams are bundled from a content server to a communication terminal through a node on the network in which communication processing is managed by a control server. In the relay device provided in the node or the gateway accommodating the communication terminal, a session control message is generated for controlling the network in units of packages according to the request based on the multicast control request transmitted from the communication terminal. A network control request means for transmitting to the control server to request network control, and a multicast control request received from the communication terminal only when a response from the control server indicates network control success. The a structure comprising a transfer means for transferring to other nodes located upstream of the multicast tree.

  (2) Used in a system for providing a content distribution service of a plurality of multicast streams from a content server to a communication terminal through a node on the network in which communication processing is managed by a control server, the node on the network or the communication terminal In the relay apparatus provided in the gateway to accommodate, a session control message for controlling the network according to the request based on the multicast control request transmitted from the communication terminal is generated and transmitted to the control server to control the network. The network control request means for requesting and forwarding for transferring the multicast control request received from the communication terminal to another node located upstream of the multicast tree only when the response from the control server indicates that the network control is successful. A configuration that includes a stage.

  (3) In (1) or (2), when the multicast control request transmitted from the communication terminal is content stream switching, the network control requesting unit determines whether the switching destination stream is in the same multicast. If it is not the same cast, a session update request is created and transmitted to the control server, and the transfer means adds the leave request for removing the switching source stream from the multicast and the switching destination stream to the multicast. The participation request is transferred to the other node.

Moreover, the relay method of the video delivery service providing system according to the present invention has the following configuration.
(4) Used in a system that provides a content distribution service of a multicast package as a package in which a plurality of multicast streams are bundled from a content server to a communication terminal through a node on the network in which communication processing is managed by a control server. In the relay method provided in the node or the gateway accommodating the communication terminal, a session control message is generated for controlling the network in units of packages according to the request based on a multicast control request transmitted from the communication terminal. The network control request is sent to the control server to request network control, and only when the response from the control server indicates network control success, the multicast control request received from the communication terminal is sent to the multicast tree. A structure to be transferred to other nodes located in the flow.

  (5) Used in a system that provides a content distribution service of a plurality of multicast streams from a content server to a communication terminal through a node on the network whose communication processing is managed by a control server, and the node on the network or the communication terminal In the relay method provided in the gateway to be accommodated, network control is performed by creating a session control message for controlling the network according to the request based on a multicast control request transmitted from the communication terminal and transmitting the session control message to the control server. The multicast control request received from the communication terminal is transferred to another node located upstream of the multicast tree only when the response from the control server indicates successful network control.

  (6) In (4) or (5), when the multicast control request transmitted from the communication terminal is a content stream switching, it is determined whether or not the switching destination stream is in the same multicast, and is not the same cast Creates a session update request and transmits it to the control server, and forwards a leave request for removing the switching source stream from the multicast and a join request for adding the switching destination stream to the multicast to the other nodes. The configuration.

The relay processing program of the video distribution service providing system according to the present invention has the following configuration.
(7) Used in a system that provides a content distribution service of a multicast package as a package in which a plurality of multicast streams are bundled from a content server to a communication terminal through a node on the network in which communication processing is managed by a control server. And a gateway that accommodates the communication terminal, and causes a computer to execute control processing on the control server and another node located upstream of the multicast tree based on a multicast control request transmitted from the communication terminal And generating a session control message for controlling the network in units of packages according to the request based on a multicast control request transmitted from the communication terminal. Request processing for requesting network control to be transmitted to a server, determination processing for determining whether a response from the control server indicates network control success, and when a response from the control server indicates success, A multicast control request received from a communication terminal is forwarded to another node located upstream of the multicast tree, and a forwarding process that does not forward when indicating failure is adopted.

  (8) Used in a system that provides a content distribution service of a plurality of multicast streams from a content server to a communication terminal through a node on the network whose communication processing is managed by a control server, and the node on the network or the communication terminal In the relay processing program provided in the accommodating gateway for causing the computer to execute control processing on the control server and another node located upstream of the multicast tree based on the multicast control request transmitted from the communication terminal, A request process for requesting network control by creating a session control message for controlling the network according to the request based on a multicast control request transmitted from a communication terminal and transmitting the request to the control server; Determination processing for determining whether or not the response from the server indicates network control success, and when the response from the control server indicates success, the multicast control request received from the communication terminal is located upstream of the multicast tree. And a transfer process that does not transfer when a failure is indicated.

  (9) In (7) or (8), when the multicast control request transmitted from the communication terminal is content stream switching, the request processing determines whether or not the switching destination stream is within the same multicast. If they are not the same cast, a session update request is created and transmitted to the control server, and the transfer process adds the leave request for removing the switching source stream from the multicast and the switching destination stream to the multicast. The participation request is transferred to the other node.

  In the video distribution service providing system and the video distribution service providing method using the relay device according to the configuration of the above aspect, a function for converting the multicast control protocol and the session control protocol is newly introduced to support the session control protocol. It is now possible to use existing communication terminals that are not available on the managed network. Also, when switching multicast streams, if the cooperation function that receives the multicast participation request always creates a session establishment request and performs network control such as session establishment and securing network resources, each time the stream is switched Since a long processing time is always required, there is a concern that the user's QoE (Quality of Experience) will be significantly reduced. Thus, in the present invention, a multicast package is used to realize high-speed stream switching by minimizing network control such as session establishment and network resource reservation in multicast stream switching.

  As a method of converting a signal transmitted from a communication terminal into SIP and performing session control, a method of converting UPnP (Universal Plug and Play) into SIP has been proposed (Non-patent Document 3). However, the existing UPnP-SIP conversion is intended for cooperation between home appliances in the home and unicast services such as VoIP (Voice over IP), and does not correspond to the multicast service as in the present invention. The present invention realizes high-speed switching of streams and the like based on circumstances unique to the multicast service, and is a method optimized for multicast.

  First, in the present invention, a node between a communication terminal and a content server creates a session control message based on a multicast participation request transmitted from the communication terminal and controls a server (hereinafter referred to as a control server) that controls the network. Request network control. If network control is successful, the node forwards the multicast join request to other nodes located upstream of the multicast tree.

The present invention has the following two features.
[Feature 1]
The present invention relays a multicast control protocol and creates a function for creating a session control message based on the contents (hereinafter referred to as a linkage function) in a home network (hereinafter referred to as HGW) in a user's home or a managed network such as NGN. It is added to the forwarding node etc.

[Feature 2]
The present invention is characterized in that the linkage function of feature 1 manages multicast packages. The cooperation function realizes high-speed stream switching by performing network control such as session establishment and securing of network resources for each package based on the received multicast participation request.

  It is also possible to adopt a form in which only the cooperation function of [Feature 1] is implemented without mounting the multicast package of [Feature 2].

  According to the present invention, by introducing a function for converting a sequential multicast control protocol and a session control protocol, it is possible to provide a video distribution service in which an existing communication terminal that does not support the session control protocol can be used in a managed network. It is possible to provide a system relay device, a relay method, and a relay processing program.

  Specifically, by using the above function, it is possible to use a multicast service with a guaranteed quality even when using an existing communication terminal that does not support the session control protocol. In addition, since the multicast package is used and the network control processing in the multicast stream switching is suppressed to the minimum necessary, the stream switching can be performed at high speed.

The block diagram which shows the multicast service implementation architecture used as the structure of the video delivery service provision system of one Embodiment which concerns on this invention. The sequence diagram which shows the reception start procedure of the multicast stream of the said embodiment. The sequence diagram which shows the switching procedure of the multicast stream of the said embodiment. The sequence diagram which shows the reception stop procedure of the multicast stream of the said embodiment. The conceptual diagram which shows the process example of the cooperation function at the time of the reception start of the multicast stream of the said embodiment. The conceptual diagram which shows the process example of the cooperation function at the time of the multicast stream switching of the said embodiment. The flowchart which shows the flow of a process for the cooperation function of the said embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing an architecture for realizing a multicast service as a configuration of a video distribution service providing system according to an embodiment of the present invention. Here, an example of an architecture when a cooperation function is implemented in the HGW is shown. In FIG. 1, reference numeral 11 denotes a network, and forwarding nodes 12 and 13 are arranged on the network 11 (one or a plurality of forwarding nodes are assumed). These forwarding nodes 12 and 13 are under the control of the control server 14. The content server 15 is connected to one transfer node 12, and the HGW 16 is connected to the other transfer node 13. The HGW 16 is equipped with a cooperation function 161 and accommodates a communication terminal 17.

  In FIG. 1, an example of a protocol to be used is shown in parentheses. There may be three or more transfer nodes between the content server 15 and the communication terminal 17 as well as 12 and 13. The cooperation function 161 may be implemented in the forwarding node 13 instead of the HGW (home gateway) 16.

  Further, in FIG. 1, only one communication terminal 17 is connected to the HGW 16, but the present invention is also applicable to a case where two or more communication terminals are connected. In addition, when a cooperation function is implemented in another node such as a forwarding node, it is applicable when one or more communication terminals are connected.

In the above configuration, the multicast stream reception processing procedure will be described with reference to FIGS.
FIGS. 2 to 4 are sequence diagrams showing the multicast stream reception start procedure, switching procedure, and reception stopping procedure, respectively. FIGS. 5 and 6 show processing examples of the cooperative function at the time of starting the reception and switching, respectively. FIG. 7 is a conceptual diagram and FIG. 7 is a flowchart showing the overall processing flow of the linkage function 161.

  First, processing at the start of multicast stream reception is performed as shown in FIG. That is, the communication terminal 17 transmits a multicast participation request (MLD) (1) to the cooperation function 161 in the HGW 16 in order to receive the multicast stream. In this participation request, for example, as shown in FIG. 5A, a multicast address of a stream desired to be received is described. Depending on the protocol used, the source address may be described in the request.

  The linkage function 161 includes a table in which stream related information (multicast address, source address, multicast package ID, necessary bandwidth, etc.) is set in advance for each multicast stream as shown in FIG. 5B, for example. Based on the above, a multicast package to which each multicast stream belongs and a network resource related parameter such as a necessary bandwidth are specified. That is, based on the input, the multicast package ID to which the corresponding multicast stream belongs and the necessary bandwidth are determined, and an output 1 session establishment request shown in FIG. 5C is created. Note that, among the network resource related parameters of each multicast package, the maximum value is set for the necessary bandwidth in any multicast stream included in the package.

  Upon receiving the multicast participation request (1), the cooperation function 161 uses the multicast address and, if necessary, the source address as a search index to specify the corresponding multicast stream and the multicast package to which the stream belongs. To do. At the same time, other stream-related information such as necessary bandwidth is extracted, and based on such information, a session establishment request (SIP) (2) as shown in FIG. 5C, for example, is created and transmitted to the control server 14 To do.

  Upon receiving the session establishment request (2), the control server 14 performs network control (3) such as session establishment of the forwarding nodes 12 and 13 and securing of network resources in order to distribute the multicast stream, and a session establishment response ( SIP) (4) is transmitted to the cooperation function 161.

  When the session establishment response (4) from the control server 14 is a response that “session establishment was successful”, the cooperation function 161 receives the multicast participation request (1) received from the communication terminal 17 as shown in FIG. Is transmitted to the forwarding node 13 as a multicast participation request (5) shown in FIG. At this point, the forwarding node 13 starts distributing the multicast stream (RTP) (6) to the communication terminal 17. The linkage function 161 stores stream-related information such as the ID of the multicast package to which the currently distributed multicast stream (6) belongs as “currently distributed stream information”. On the other hand, the cooperation function 161 does not transmit a multicast participation request to the forwarding node 13 when the session establishment response (4) from the control server 14 is a response that “session establishment has failed”.

  When the cooperation function 161 is implemented in the HGW 16, if the reason why the session establishment has failed is "the user does not have the authority to receive the corresponding multicast stream", the cooperation function 161 The corresponding multicast stream information may be deleted from the table. If this process is always performed, it means that the user has no authority to receive a multicast stream that does not exist in the table. Therefore, when the cooperation function 161 receives such a multicast stream participation request, it is not necessary to execute unnecessary session establishment processing. As a result, the processing load on the HGW 16 and the control server 14 can be reduced.

  Next, when the communication terminal 17 viewing a certain multicast stream switches to another multicast stream, the procedure shown in FIG. 3 is performed. As a specific use case, there is a case in which a user who is watching a multicast channel program switches to another channel program.

In the present invention, since a plurality of multicast streams are bundled as a single multicast package, stream switching is classified into the following two types.
A. When switching streams within the same multicast package
B. When switching streams across different multicast packages With the communication terminal 17 receiving the video stream 1 (RTP) (7) from the transfer node 13 via the HGW 16, the program switching operation of another channel by the user Assume that a multicast participation request (MLD) (8) as shown in FIG. 6A is transmitted from the communication terminal 17 to the cooperation function 161. When the cooperation function 161 receives the multicast participation request (8), for example, with reference to the table shown in FIG. 6B, the cooperation function 161 determines whether other multicast streams are currently being distributed to the same communication terminal 17. If it is confirmed that it is being distributed, it is determined based on the information of the multicast package ID to which the currently distributed multicast stream belongs, whether the above A or B is applicable.

  Here, in the table in the cooperation function 161, the multicast package ID to which the corresponding multicast stream belongs is specified based on the input. In the example shown in FIG. 6B, the requested stream corresponds to the package A, but since the package A is currently being distributed, no new session update request is made.

  As described above, since the maximum amount of network resources is secured in any multicast stream included in the same multicast package in the session establishment process, “A. When switching streams within the same multicast package” ", There is no need to secure new network resources. Therefore, in the case of A, the cooperation function 161 does not perform the session update process, and transmits a multicast control request (MLD) (9) including the multicast withdrawal request and the multicast participation request shown in FIG. Then, it leaves the multicast stream currently being distributed and joins a new multicast stream (video stream 2 (RTP)).

  On the other hand, in “B. When switching streams across different multicast packages”, there is a possibility that network resources required for distribution of multicast streams may change. Therefore, as in the session establishment process, the cooperation function 161 creates a session update request based on the multicast participation request (8), executes network control through the control server 14, and then sends the multicast control request (9) to the forwarding node 13. Send.

  Next, when stopping the reception of the multicast stream, the procedure shown in FIG. 4 is performed. The communication terminal 17 transmits a multicast withdrawal request (MLD) (12) to the cooperation function 161 while receiving the video stream (RTP) (11). Upon receiving the request (12), the cooperation function 161 identifies a corresponding session based on information such as a multicast address included in the multicast withdrawal request (12), creates a session release request (SIP) (13), It transmits to the control server 14. The control server 14 that has received the request (13) performs network control (14) such as session release and network resource release, and transmits a session release response (SIP) (15) to the cooperation function 161.

  When the cooperation function 161 is a response indicating that the received session release response (15) is successful, the cooperation function 161 transmits the multicast withdrawal request (12) → (15) received from the communication terminal 17 to the forwarding node 13 and “Stream information currently being distributed” held by is empty. If the session release response (15) is a response indicating failure, a session release request is created again and transmitted to the control server.

FIG. 7 shows a flow of a series of processes of the cooperation function 161.
First, when a multicast control request is received from the communication terminal 17 (step S1), it is determined whether or not the request is a participation request (step S2). If Yes, stream related information is determined based on the multicast address or the like (step S2). Step S3). Subsequently, it is determined whether another stream is currently being distributed to the same communication terminal 17 (step S4). If Yes, it is determined whether a stream of the same multicast package is already being distributed (step S5). A multicast withdrawal request (for the old stream) and a participation request (for the new stream) are transmitted to the transfer node 13 (step S6), and the contents of the “currently distributed stream information” are updated (step S7). Exit.

  In the case of No in step S5, a session update request is created and transmitted to the control server 14 (step S8). Here, a response from the control server 14 is received to determine whether the session has been successfully established (step S9). If Yes, the process returns to step S6 to continue the process. If No, the process proceeds to step S7. .

  If No in step S4, a session establishment request is created and transmitted to the control server 14 (step S10). Here, a response from the control server 14 is received to determine whether the session has been successfully established (step S11). If Yes, a multicast participation request is transmitted to the forwarding node 13 (step S12). The process proceeds to step S7 as it is.

  If it is determined No in step S2, the received multicast control request is a multicast leave request. Therefore, the corresponding session is determined based on the multicast address or the like (step S13), and a session release request is created and controlled. It transmits to the server 14 (step S14). A session release response from the control server 14 is received to determine whether the session release is successful (step S15), and the process of step S14 is executed until the success is confirmed. When the session release is successful, a multicast leaving request is transmitted to the forwarding node 13 (step S16), and the process proceeds to step S7.

  By using the cooperation function 161 that executes the above-described processing, it is possible to use a multicast service with a guaranteed quality even when using an existing communication terminal 17 that does not support the session control protocol. Further, since the cooperation function 161 minimizes the network control processing in the multicast stream switching using the multicast package, the stream switching can be performed at high speed.

  On the other hand, service update processing (update of multicast package change stream related information, etc.) can be realized simply by updating the settings of the table etc. held by the linkage function 161. (Communication terminal 17 replacement, firmware update, etc.) do not occur. Furthermore, since the specification change of the session control protocol can be realized by performing processing such as changing the conversion rule between the multicast control protocol and the session control protocol in the cooperation function 161, there is no impact on the communication terminal being used. .

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some configurations may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different example embodiments may be combined as appropriate.

   DESCRIPTION OF SYMBOLS 11 ... Network 12, 13 ... Transfer node, 14 ... Control server, 15 ... Content server, 16 ... HGW (home gateway), 161 ... Cooperation function, 17 ... Communication terminal.

Claims (9)

Used in a system for providing a content distribution service of a multicast package as a package in which a plurality of multicast streams are bundled from a content server to a communication terminal through a node on the network in which communication processing is managed by a control server. In the relay device provided in the gateway accommodating the communication terminal,
Network control request means for creating a session control message for controlling the network in units of packages according to a request based on a multicast control request transmitted from the communication terminal and transmitting the request to the control server to request network control; ,
And a transfer means for transferring a multicast control request received from the communication terminal to another node located upstream of the multicast tree only when a response from the control server indicates a successful network control. Relay device for distribution service system. Gateway used in a system for providing a content distribution service of a plurality of multicast streams from a content server to a communication terminal through a node on the network whose communication processing is managed by a control server, and accommodates the node on the network or the communication terminal In the relay device provided in
Network control request means for creating a session control message for controlling the network according to a request based on a multicast control request transmitted from the communication terminal and transmitting the request to the control server to request network control;
Forwarding means for forwarding a multicast control request received from the communication terminal to another node located upstream of the multicast tree only when a response from the control server indicates network control success ;
In the transfer means, a response from the control server to the session establishment request created as the session control message indicates a session establishment failure, and the failure is “the communication terminal does not have authority to receive a multicast stream”. The relay device of the content distribution service system , wherein the multicast stream information is deleted from the multicast stream related information table included in the multicast control request . When the multicast control request transmitted from the communication terminal is a content stream switching, the network control requesting unit determines whether or not the switching destination stream is in the same multicast. And send it to the control server,
3. The transfer unit according to claim 1, wherein the transfer unit transfers a leaving request for removing the switching source stream from the multicast and a participation request for adding the switching destination stream to the multicast to the other node. Relay device for content distribution service system. Used in a system for providing a content distribution service of a multicast package as a package in which a plurality of multicast streams are bundled from a content server to a communication terminal through a node on the network in which communication processing is managed by a control server. In the relay method provided in the gateway accommodating the communication terminal,
Based on a multicast control request sent from the communication terminal, create a session control message for controlling the network in units of packages according to the request and send it to the control server to request network control,
A relay method for a content distribution service system, wherein the multicast control request received from the communication terminal is forwarded to another node located upstream of the multicast tree only when a response from the control server indicates successful network control. . Gateway used in a system for providing a content distribution service of a plurality of multicast streams from a content server to a communication terminal through a node on the network whose communication processing is managed by a control server, and accommodates the node on the network or the communication terminal In the relay method provided in
Based on a multicast control request transmitted from the communication terminal, a session control message for causing the network to be controlled according to the request is created and transmitted to the control server to request network control.
Only when the response from the control server indicates network control success, the multicast control request received from the communication terminal is transferred to another node located upstream of the multicast tree ,
In the forwarding process, a response from the control server to the session establishment request created as the session control message indicates a session establishment failure. The failure indicates that “the communication terminal does not have authority to receive a multicast stream. ”, The information of the corresponding multicast stream is deleted from the multicast stream related information table included in the multicast control request . When the multicast control request transmitted from the communication terminal is content stream switching, it is determined whether or not the switching destination stream is in the same multicast, and if it is not the same cast, a session update request is created and the control server To
6. The content distribution service system according to claim 4, wherein a leaving request for removing the switching source stream from the multicast and a joining request for adding the switching destination stream to the multicast are transferred to the other node. Relay method. Used in a system for providing a content distribution service of a multicast package as a package in which a plurality of multicast streams are bundled from a content server to a communication terminal through a node on the network in which communication processing is managed by a control server. Relay processing that is provided in a gateway that accommodates the communication terminal and causes the computer to execute control processing on the control server and other nodes located upstream of the multicast tree based on a multicast control request transmitted from the communication terminal In the program
A request process for creating a session control message for controlling the network in units of packages according to a request based on a multicast control request transmitted from the communication terminal and transmitting the request to the control server to request network control;
A determination process for determining whether a response from the control server indicates network control success;
A transfer process that transfers a multicast control request received from the communication terminal to another node located upstream of the multicast tree when a response from the control server indicates success, and does not transfer when a failure is indicated. A relay processing program for a content distribution service system. Gateway used in a system for providing a content distribution service of a plurality of multicast streams from a content server to a communication terminal through a node on the network whose communication processing is managed by a control server, and accommodates the node on the network or the communication terminal In a relay processing program for causing a computer to execute control processing on the control server and another node located upstream of the multicast tree based on a multicast control request transmitted from the communication terminal,
A request process for creating a session control message for controlling the network according to a request based on a multicast control request transmitted from the communication terminal and transmitting the request to the control server to request network control;
A determination process for determining whether a response from the control server indicates network control success;
When the response from the control server indicates success, the multicast control request received from the communication terminal is transferred to other nodes located upstream of the multicast tree, and when it indicates failure, transfer processing that does not transfer ,
In the transfer process, a response from the control server to the session establishment request created as the session control message indicates a session establishment failure, and the failure is “the communication terminal does not have authority to receive a multicast stream”. The relay processing program of the content distribution service system , wherein the multicast stream information is deleted from the multicast stream related information table included in the multicast control request . Further, when the multicast control request transmitted from the communication terminal is content stream switching,
The request processing determines whether or not the switching destination stream is in the same multicast, and if it is not the same cast, creates a session update request and sends it to the control server,
9. The transfer process according to claim 7 or 8, wherein the transfer process transfers a leaving request for removing the switching source stream from the multicast and a participation request for adding the switching destination stream to the multicast to the other node. Relay processing program for the content distribution service system.

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