JP4194956B2 - Multicast data communication system, branching device, and computer program - Google Patents

Description

  The present invention relates to a multicast data communication system that distributes data to a plurality of clients by duplicating the data sent by the server, and a distribution route that captures the reception request that each client sends to the server. The present invention relates to a branching device to be constructed and a computer program.

As a method to realize multicast communication that broadcasts data to multiple clients, a branching device captures the reception request from the client and becomes a branching point, thereby constructing a tree-like (tree-like) distribution route Multicast data communication systems are known.
For example, the client repeatedly sends a reception request called a request packet to the server, the branching device installed on the path from the client to the server captures the reception request, and records the transmission source in the registration table, so that the branch point (For example, refer to Patent Document 1).

Here, the conventional method will be described with reference to FIGS. FIG. 17 is a block diagram showing a configuration example of a conventional multicast data communication system.
17 to 24, the server 1 'and the clients 3 and 4 are connected by a branching device 2'. The server 1 ′ and the branch device 2 ′ manage the registration table 5 ′ and the registration table 6 ′, respectively. In each row of the registration tables 5 ′ and 6 ′, a server name and a child (a partner to which data is transmitted) that receives data from the server are recorded. For example, if the registration table 6 ′ of the branching device 2 ′ includes a line “server 1 ′: client 3, client 4”, the branching device 2 ′ transmits the data received from the server 1 ′ to the client 3 And relay to the client 4. Here, first, consider a situation in which a reception request is made to the server 1 ′ in the order of the clients 3 and 4, and finally the client 4 stops receiving.

In FIG. 18, the client 3 transmits a reception request 10 addressed to the server 1 ′. The branching device 2 ′ captures the reception request 10 that is going to pass through, and records the client 3 that is the transmission source in the row of the server 1 ′ of the registration table 6 ′ (“server 1 ′: client 3”). .
Then, as illustrated in FIG. 19, the branching device 2 ′ transmits a reception request 11 to the server 1 ′ instead of the client 3. The server 1 ′ that has received the reception request 11 records the branch device 2 ′ that is the transmission source in the row of the server 1 ′ in the registration table 5 ′ (“server 1 ′: branch device 2 ′”).

Next, data transmission will be described with reference to FIG. The server 1 ′ transmits the data 12 to the branch device 2 ′ recorded in the row of the server 1 ′ of the registration table 5 ′. When receiving the data 12 from the server 1 ′, the branching device 2 ′ relays the data 13 to the client 3 recorded in the row of the server 1 ′ in the registration table 6 ′.
In this way, when there is only one receiving device (client), the branching device 2 ′ does not need to perform relay processing. However, the branching device 2 ′ performs a relay process of inspecting the transmission source of the received data packet, searching the registration table 6 ′, and rewriting and sending the destination.

  FIG. 21 shows a state in which the client 4 is registered in the branch device 2 '. In FIG. 21, the client 4 transmits a reception request 14 addressed to the server 1 '. When the branching device 2 ′ captures the reception request 14 transmitted from the client 4 to the server 1 ′, the branching device 2 ′ adds the client 4 as the transmission source to the row of the server 1 ′ in the registration table 6 ′ (“server 1 ′: client”). 3, client 4 "). Since the branching device 2 'has already transmitted the reception request 11 to the server 1', there is no need to send it again. At this time, the data is transmitted as shown in FIG.

  In FIG. 22, first, the server 1 ′ transmits the data 15 to the branch device 2 ′ recorded in the row of the server 1 ′ in the registration table 5 ′. Subsequently, the branching device 2 ′ searches the row of the server 1 ′ in the registration table 6 ′, duplicates the received data because there are a plurality of distribution destinations, and rewrites the data 16 and the data 17 that are rewritten to the client 3 respectively. And relay to client 4.

  Finally, the client 4 stops receiving. In FIG. 23, the client 4 transmits a stop request 18 addressed to the server 1 '. The branching device 2 'captures the stop request 18 that attempts to pass through itself, and deletes the client 4 that is the transmission source from the row of the server 1' in the registration table 6 '("server 1': client 3"). At this time, the data is transmitted as shown in FIG.

  In FIG. 24, the server 1 ′ transmits the data 19 to the branch device 2 ′ recorded in the row of the server 1 ′ in the registration table 5 ′. When receiving the data 19 from the server 1 ′, the branching device 2 ′ relays the data 20 to the client 3 recorded in the row of the server 1 ′ in the registration table 6 ′. Similar to FIG. 20, the branching apparatus 2 ′ performs processing such as transmission source inspection, registration table search, and destination rewriting, even though branching is not necessary.

On the other hand, PIM-SM (Personal Independent Multicast-Sparse Mode), one of the protocols for constructing a multicast tree, is not a server that is a direct data supplier or a client that is a direct data receiver. A router installed on the same subnet or a virtual server called a rendezvous point transmits and receives a reception request.
That is, the router installed in the same subnet as the client transmits a reception request called “join” to a router installed in the same subnet as the rendezvous point or server. A branching device (usually called a multicast router) installed on the path of the Join packet captures this join and records its source in the registration table to become a branch point. Also, when a router installed in the same subnet as the client stops data reception, it sends a stop request called prune to a rendezvous point or a router installed in the same subnet as the server. The multicast router installed on the route of the Prune packet captures this prune and deletes its transmission source from the registration table.
Also in this case, the branching device in a situation where branching is not necessary performs processing such as transmission source inspection, registration table search, and destination rewriting.
JP 2003-32300 A

  The multicast data communication system and the PIM-SM compliant branching device disclosed in the above-mentioned Patent Document 1 have a number of branches even when a reception request is received only from one client or a downstream branching device. Even if the data is 1, relay processing for data branching such as inspection of the transmission source of received data, search of a registration table, and data transmission to a client or a downstream branching device is performed. In the multicast data communication system disclosed in Patent Document 1, it is also required to change the destination of the data packet. Originally, when the number of branches is 1, such relay processing is unnecessary, and it is desirable to avoid this relay processing in order to reduce the load on the branch device.

  The present invention has been made in view of the above circumstances. In a multicast data distribution, when a branching device that branches a received data packet to a plurality of clients does not need to branch the data packet, the relay for data branching is performed. An object of the present invention is to provide a multicast data communication system, a branching device, and a computer program that reduce the load on the branching device by avoiding the processing and improve the performance.

  The present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 is characterized in that one or more servers and two or more clients are connected via one or more branch devices, and the branch device is provided. Has a registration table that records the destination of data sent from this server and the server, and captures a request to receive data sent to that server when it is on the communication path of the client and server In addition, the client or other branching device that is the transmission source of the reception request is registered as a data transmission destination corresponding to the destination server of the reception request in the registration table provided inside, and a new reception is made to the destination server A series of operations for generating and transmitting a request is repeated until the reception request reaches the destination server, thereby constructing a tree-like distribution route rooted in the server. When the data is transmitted to the transmission destination corresponding to the own server registered in the registration table provided, the branch device that has received the data refers to the registration table provided therein and corresponds to the server that is the transmission source of the data. In a multicast data communication system in which a series of operations for copying and transmitting the data to a distribution destination to be repeated until the data reaches all clients, the branching device receives data sent from the client or another branching device to the server. A registration operation unit that captures a request and corresponds to the destination server of the reception request, and registers the client or other branching device that is the transmission source of the reception request as a transmission destination in the registration table; As a result, when the number of transmission destinations is other than 2, the reception request is made transparent, and when the number of transmission destinations is 2, the data transmission destination is transferred to the own branching device. A change request generation unit that generates a change request for requesting update and transmits the change request to the destination server; receives data transmitted from the server; and transmits data corresponding to the server registered in the registration table A packet transmission unit that transmits the data when the destination number is 1, and copies and transmits the data to the destination client or other branch device when the destination number is 2 or more; When the server receives the reception request, the server writes the client or branching device that is the transmission source of the reception request into the registration table that is internally provided as a transmission destination corresponding to itself, and receives the change request. A multicast data communication system, comprising: a registration operation unit that changes a transmission destination corresponding to itself in the registration table to a transmission destination designated by the change request. Is.

  The invention according to claim 2 is the multicast data communication system according to claim 1, wherein the registration operation unit of the branch device captures a change request transmitted to the server by another branch device, The transmission destination corresponding to the destination server of the change request in the registration table provided inside is changed to the transmission destination specified by the change request.

According to a third aspect of the present invention, one or more servers and two or more clients are connected via one or more branching devices, and the branching device has one server and data transmitted from this server. A registration table for recording the transmission destination of the client, and when it is on the communication path between the client and the server, captures a reception request for data transmitted to the server, and stores the destination of the reception request in the registration table provided inside A series of operations for registering a client or other branching device that is the transmission source of the reception request as a data transmission destination corresponding to the server and generating and transmitting a new reception request to the destination server Builds a tree-like distribution route rooted in the server by repeating until it reaches the destination server, and the server is registered in an internal registration table and corresponds to its own server When the data is transmitted to the receiver, the branching device that has received the data refers to an internal registration table and copies and transmits the data to the delivery destination corresponding to the server that is the source of the data In a multicast data communication system that repeats a series of operations until data reaches all clients, the branching device captures a data stop request transmitted to a server by a client or another branching device, and includes the registration therein A registration operation unit that deletes the client or other branch device that is the transmission source of the stop request from the transmission destination corresponding to the destination server of the stop request in the table, and the number of transmission destinations is 0 as a result of the deletion the stop request and sends it to the server, in the case the number of the destination is 1, the destination of the data from its own branch device, captured the stop request The non-client or other branching device Xinyuan, the change produces a change request requesting to change the registration client or other branching devices registered in the table and transmits it to the destination server request generation And the data transmitted from the server, and when the number of data destinations corresponding to the server registered in the registration table is 1, the data is transmitted and the number of destinations is 2 or more. A packet transmission unit that replicates and transmits the data to the destination client or other branching device, and the server receives the stop request and has a registration table provided therein. Delete the client or branch device that is the transmission source of the stop request from the transmission destination corresponding to itself, and when the change request is received, the transmission destination corresponding to itself in the registration table is A multicast data communication system comprising a registration operation unit for changing to a transmission destination designated by a change request.

  The invention according to claim 4 is the multicast data communication system according to claim 3, wherein the registration operation unit of the branch device captures a change request transmitted to the server by another branch device, The transmission destination corresponding to the destination server of the change request in the registration table provided inside is changed to the transmission destination specified by the change request.

  In the invention according to claim 5, one or more servers and two or more clients are connected via one or more branching devices, and the branching device has one server and data transmitted from this server. A registration table for recording the transmission destination of the client, and when it is on the communication path between the client and the server, captures a reception request for data transmitted to the server, and stores the destination of the reception request in the registration table provided inside A series of operations for registering a client or other branching device that is the transmission source of the reception request as a data transmission destination corresponding to the server and generating and transmitting a new reception request to the destination server Builds a tree-like distribution route rooted in the server by repeating until it reaches the destination server, and the server is registered in an internal registration table and corresponds to its own server When the data is transmitted to the receiver, the branching device that has received the data refers to an internal registration table and copies and transmits the data to the delivery destination corresponding to the server that is the source of the data A branching device used in a multicast data communication system that repeats a series of operations until data reaches all clients, and captures a reception request transmitted to a server by a client or another branching device, and receives the destination of the reception request Corresponding to the server, the registration operation unit that registers the client or other branching device that is the transmission source of the reception request as the transmission destination in the registration table, and the registration result indicates that the number of transmission destinations is other than 2. In some cases, the reception request is made transparent, and when the number of transmission destinations is 2, a change request is generated to request that the data transmission destination be changed to the own branch device. A change request generation unit for transmitting to the destination server, and when data transmitted from the server is received, and the number of data destinations corresponding to the server registered in the registration table is 1, A branching device comprising: a packet transmission unit that transmits data and copies the data to the destination client or other branching device when the number of destinations is two or more; It is.

  The invention according to claim 6 is the branching device according to claim 5, wherein the registration operation unit captures the change request transmitted to the server by another branching device and includes the registration therein. The transmission destination corresponding to the destination server of the change request in the table is changed to the transmission destination specified by the change request.

According to the seventh aspect of the present invention, one or more servers and two or more clients are connected via one or more branch devices, and the branch device includes one server and data transmitted from this server. A registration table for recording the transmission destination of the client, and when it is on the communication path between the client and the server, captures a reception request for data transmitted to the server, and stores the destination of the reception request in the registration table provided inside A series of operations for registering a client or other branching device that is the transmission source of the reception request as a data transmission destination corresponding to the server and generating and transmitting a new reception request to the destination server Builds a tree-like distribution route rooted in the server by repeating until it reaches the destination server, and the server is registered in an internal registration table and corresponds to its own server When the data is transmitted to the receiver, the branching device that has received the data refers to an internal registration table and copies and transmits the data to the delivery destination corresponding to the server that is the source of the data A branching device used in a multicast data communication system that repeats a series of operations until data reaches all clients, and captures a data stop request sent to a server by a client or another branching device, A registration operation unit that deletes the client or other branch device that is the transmission source of the stop request from the transmission destination corresponding to the destination server of the stop request in the registration table, and the number of transmission destinations is 0 as a result of the deletion. directly transmitted to the server the stop request when it is, when the number of the destination is 1, the destination of the data from its own branch device and captured Serial other than the client or other branching device of the transmission source stop request, transmits the generated change request requesting to change the registration client or other branching devices registered in the table to the destination server A change request generation unit that receives data transmitted from a server, and when the number of transmission destinations of data corresponding to the server registered in the registration table is 1, the data is transmitted, When the number is two or more, the branching device includes a packet transmission unit that duplicates and transmits the data to the destination client or other branching device.

  The invention according to claim 8 is the branching device according to claim 7, wherein the registration operation unit captures a change request transmitted to the server by another branching device and includes the registration therein. The transmission destination corresponding to the destination server of the change request in the table is changed to the transmission destination specified by the change request.

  According to the ninth aspect of the invention, one or more servers and two or more clients are connected via one or more branching devices, and the branching device has one server and data transmitted from this server. A registration table for recording the transmission destination of the client, and when it is on the communication path between the client and the server, captures a reception request for data transmitted to the server, and stores the destination of the reception request in the registration table provided inside A series of operations for registering a client or other branching device that is the transmission source of the reception request as a data transmission destination corresponding to the server of the server and generating and transmitting a new reception request to the destination server Builds a tree-like distribution route rooted in the server by repeating until it reaches the destination server, and the server is registered in an internal registration table and corresponds to its own server When the data is transmitted to the receiver, the branching device that has received the data refers to an internal registration table and copies and transmits the data to the delivery destination corresponding to the server that is the source of the data A computer program used for a branching device in a multicast data communication system that repeats a series of operations until data reaches all clients, and captures a reception request transmitted to a server by a client or another branching device Corresponding to the destination server of the request, a step of registering the client or other branching device that is the transmission source of the reception request as a transmission destination in the internal registration table, and as a result of registration, the number of transmission destinations is other than 2. If the number of transmission destinations is 2, the data transmission destination is changed to the own branching device. Generating a change request to be generated and transmitting the change request to the destination server; receiving data transmitted from the server; and the number of destinations of data corresponding to the server registered in the registration table is one And transmitting the data to the client or other branching device of the transmission destination when the number of transmission destinations is 2 or more, and causing the computer to execute the data. It is a computer program characterized.

  The invention according to claim 10 is the computer program according to claim 9, which captures the change request transmitted to the server by another branching device and stores the change request in the registration table provided inside. And a step of changing the destination corresponding to the destination server to the destination specified by the change request.

According to the eleventh aspect of the present invention, one or more servers and two or more clients are connected via one or more branching devices, and the branching device has one server and data transmitted from this server. A registration table for recording the transmission destination of the client, and when it is on the communication path between the client and the server, captures a reception request for data transmitted to the server, and stores the destination of the reception request in the registration table provided inside A series of operations for registering a client or other branching device that is the transmission source of the reception request as a data transmission destination corresponding to the server and generating and transmitting a new reception request to the destination server Is repeated until it reaches the destination server, a tree-like distribution route rooted at the server is constructed, and the server is registered in an internal registration table and corresponds to its own server. When the data is transmitted to the transmission destination, the branching device that has received the data refers to an internal registration table, and copies and transmits the data to the distribution destination corresponding to the server that is the transmission source of the data. A computer program used for a branching device in a multicast data communication system that repeats a series of operations until data reaches all clients, and captures a data stop request transmitted to a server by a client or another branching device, The step of deleting the client or other branching device that is the transmission source of the stop request from the transmission destination corresponding to the destination server of the stop request in the registration table provided inside, and the number of transmission destinations is 0 as a result of the deletion. the stop request and sends it to the server in the case where, when the number of the destination is 1, their destination of data From the device, captured other than the client or other branching unit of the transmission source of the stop request, generates a change request requesting to change the registration client or other branching devices registered in tables the Transmitting to the destination server, receiving the data transmitted from the server, and transmitting the data when the number of data destinations corresponding to the server registered in the registration table is 1, When the number of transmission destinations is 2 or more, a computer program that causes a computer to execute a step of copying and transmitting the data to the client or other branching device of the transmission destination.

  The invention according to claim 12 is the computer program according to claim 11, which captures the change request transmitted to the server by another branching device and stores the change request in the registration table provided therein. And a step of changing the destination corresponding to the destination server to the destination specified by the change request.

  According to the present invention, in a multicast distribution system in which a branching device that branches data distributed by multicast captures a reception request from a client to a server and constructs a multicast distribution route, When it is not necessary to branch the data in the branching device for the data packet to be transmitted, it is possible to avoid the branching device performing relay processing for branching the data packet. As a result, the load on the branching device can be reduced and the performance of data distribution can be improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing a configuration example of a multicast data communication system according to an embodiment of the present invention. The multicast data communication system according to the present embodiment is formed by connecting one or more servers 1 and two or more clients via one or more branching devices 2. Here, for the sake of simplicity, description will be given using a configuration in which one server 1 and two clients 3 and 4 are connected via one branch device 2. The server 1 holds and manages the registration table 5, and the branching device 2 holds the registration table 6. In the registration table 5 and the registration table 6, a server name and a child (a partner to which data is to be transmitted) that receives data from the server are recorded. For example, if the line “server 1: client 3, client 4” is described in the registration table 6 of the branch device 2, the branch device 2 relays the data received from the server 1 to the client 3 and the client 4. It means to do. Here, a situation is considered in which a reception request for requesting data reception is first made to the server 1 in the order of the clients 3 and 4 and finally the client 4 stops receiving data.

  2 to 16 are diagrams showing a state of data distribution according to the embodiment shown in FIG. 1, and FIGS. 10 and 11 are sequence diagrams showing an operation sequence of the multicast data communication system shown in FIGS. It is. Here, the flow of operations among the server 1, the branch device 2, and the clients 3 and 4 is shown. Hereinafter, the operation of the embodiment of the present invention will be described in detail with reference to FIGS.

First, in FIG. 2, the client 3 transmits a reception request 50 for requesting data reception to the server 1 (FIG. 10: step S310). When the first reception request 50 addressed to the server 1 passes through the branching device 2, the branching device 2 records the client 3 as the transmission source as a child (data transmission destination) in the row of the server 1 in the registration table 6 ( “Server 1: Client 3”) (FIG. 10: Step S315). When the registered number of children of the row of the server 1 in the registration table 6 after the registration of the client 3 is 1, the branching device 2 does not terminate the reception request 50, and without changing the destination and the transmission source, the server 1 as it is. Forward to.
When the reception request 50 arrives, the server 1 records the client 3 that is the transmission source of the reception request 50 in the row of the server 1 in the registration table 5 (“server 1: client 3”) (FIG. 10: step S320). .

  Distribution of data at this time is performed as shown in FIG. The server 1 transmits the data 51 to the client 3 recorded in the row of the server 1 in the registration table 5 (FIG. 10: Step S325). At this time, since the number of registered children in the registration table 6 is 1, the branching device 2 performs relay processing for data branching (hereinafter simply referred to as relay processing), that is, transmission source inspection of data 51, registration table search, Transfer to the client 3 as it is without performing processing such as rewriting the destination.

  Next, as shown in FIG. 4, the client 4 transmits a reception request 52 for requesting reception of data to the server 1 (FIG. 10: Step S330). The branching device 2 registers the client 4 that is the transmission source of the reception request 52 that is going to pass through itself in the row of the server 1 in the registration table 6 (“server 1: client 3, client 4”) (FIG. 10: Step S335). At this time, the branching device 2 terminates the reception request 52 because the number of registered children is 2. Then, as shown in FIG. 5, a change request 53 instructing to change the data transmission destination from the already registered client 3 to the branch device 2 is transmitted to the server 1 (step S340). Upon receiving the change request 53, the server 1 changes the client 3 registered in the row of the server 1 in the registration table 5 to the branch device 2 (“server 1: branch device 2”) (FIG. 10: step S345). .

  After the registration tables 5 and 6 are changed, the data is distributed as shown in FIG. First, the server 1 transmits the data 54 addressed to the branch device 2 recorded in the row of the server 1 in the registration table 5 (FIG. 10: step S350). When the branching device 2 receives the data 54 from the server 1, the branching device 2 searches the row of the server 1 in the registration table 6, and duplicates the data 54 because there are a plurality of children to be distributed to the client 3 and the client 4. And data 56 are generated. Then, the data 55 is transmitted to the client 3 and the data 56 is transmitted to the client 4 (FIG. 10: Step S355, Step S360).

  Subsequently, in FIG. 7, the client 4 requests to stop receiving data. That is, the client 4 transmits a stop request 57 to the server 1 (FIG. 11: step S410). The branching device 2 captures the stop request 57 addressed to the server 1 trying to pass through itself, and deletes the client 4 that is the transmission source from the row of the server 1 in the registration table 6 (FIG. 11: step S415). At this time, since the number of registered children of the row of the server 1 in the registration table 6 is 1, the branching device 2 does not need to perform branch processing. Then, as shown in FIG. 8, the branching device 2 changes the child registered in the registration table 5 from the branching device 2 to the client 3 registered only in the row of the server 1 in the registration table 6. A change request 58 instructing to do so is transmitted to the server 1 (FIG. 11: step S420). Upon receiving the change request 58, the server 1 changes the branch device 2 recorded in the row of the server 1 in the registration table 5 to the client 3 (FIG. 11: Step S425).

  FIG. 9 shows the state of data distribution at this time. The server 1 transmits data 59 to the client 3 recorded in the row of the server 1 in the registration table 5 by the same procedure as in FIG. Since the number of registered children in the registration table 6 is 1, the branching device 2 transfers the data 59 to the client 3 without performing relay processing such as transmission source inspection, registration table search, and destination rewriting (FIG. 11: Step S430). ).

  Next, operations of the server 1 and the branch device 2 will be described with reference to FIGS. FIG. 12 is a block diagram showing only the parts related to the reception request process, the stop request process, and the change request process extracted from the elements constituting the server 1 and the branching device 2. FIGS. 13 to 15 are flowcharts of processes related to reception requests, stop requests, and change requests. Although the operation in the branch device 2 will be described below, the server 1 operates in the same manner. However, since the end point of each request packet is the server 1, the server 1 does not transmit the request packet. Specifically, in FIGS. 12 to 15, the middle broken line square is a function that only the branching device 2 has.

  In FIG. 12, the branching apparatus 2 determines the registration status of the packet reception unit 200 that receives a packet, the packet transmission unit 201 that transmits a packet, the packet type determination unit 202 that determines the type of the received packet, and the registration table 207. From the registration status determination unit 203, the registration operation unit 205 that operates the contents of the registration table 207, the change request generation unit 206 that generates a change request, and the recording device that stores the registration table 207 (such as the registration table 6) Become. The server 1 also includes a packet reception unit 100, a packet transmission unit 101, a packet type determination unit 102, a registration status determination unit 103, a registration operation unit 105, and a recording device that stores a registration table 107 (such as the registration table 5). Become. The functions of the packet receiving unit 100, the packet transmitting unit 101, the packet type determining unit 102, the registration status determining unit 103, and the registration operation unit 105 of the server 1 are the packet receiving unit 200, the packet transmitting unit 201, and the packet of the branching device 2, respectively. This is the same as the seed determination unit 202, registration status determination unit 203, and registration operation unit 205.

First, an operation when a reception request attempts to pass through the branching device 2 will be described.
In FIG. 13, when the branching device 2 receives a packet from the packet receiving unit 200 (step S610), the packet type determining unit 202 determines the type of packet (step S615). Here, the received packet is a reception request, the destination is the server 110, and the transmission source node is the transmission source 111. Here, the node indicates a client or (other) branching device 2.
When the received packet is a reception request, in FIG. 14, the registration status determination unit 203 confirms whether the row of the server 110 exists in the registration table 207 (step S710). As a result, if there is no row for the server 110, the registration operation unit 205 creates a row for the server 110 in the registration table 207 (step S715). Next, the registration status determination unit 203 checks whether the transmission source 111 is registered in the row of the server 110 in the registration table 207 (step S720). If not registered, the registration operation unit 205 registers the transmission source 111 in the row of the server 110 in the registration table 207 (step S725). Finally, the registration status determination unit 203 checks the number of registrations in the row of the server 110 in the registration table 207 (step S730). If the registered number of children is 1, the packet transmission unit 201 transmits the reception request as it is to the server 110 (step S735).

  On the other hand, assume that the number of registrations is 2 in step S730. At this time, a node that has already been registered before the transmission source 111 is registered in the row of the server 110 in the registration table 207 in step S725 is referred to as a node 112. In this case, the change request generation unit 206 generates a change request instructing the exchange of the node 112 and the branch device 2 as a child of the server 110 (step S740), and the packet transmission unit 201 transmits the change request to the server 110 (step S745). ).

  When the registration status determination unit 203 determines in step S720 that the transmission source 111 is registered in the row of the server 110 in the registration table 207, the registration status determination unit 203 determines that the registration status determination unit 203 stores the registration table 207 in the registration table 207 in step S730. If it is determined that the registered number of children in the row of the server 110 is greater than 2, the branch device 2 ends the process.

  Next, a case where a stop request is received will be described using FIG. If the packet type determination unit 202 determines in step S615 in FIG. 13 that the received packet is a stop request, the registration status determination unit 203 determines whether the stop table destination server row exists in the registration table 207. Confirmation is made (step S810). Here, it is assumed that the destination of the received stop request is the server 120 and the transmission source node is the transmission source 121.

  If the registration status determination unit 203 determines that there is a row of the server 120 that is the destination of the stop request in the registration table 207, it continues to check whether the transmission source 121 exists in the row of the server 120 in the registration table 207 (step). S815). When the transmission source 121 exists in the row of the server 120 in the registration table 207, the registration operation unit 205 deletes the transmission source 121 from the row of the server 120 in the registration table 207 (step S820).

Subsequently, the registration status determination unit 203 checks the number of registered children in the row of the server 120 in the registration table 207 (step S825). If the registration number is 0, the packet transmission unit 201 transmits the stop request as it is to the destination server 120 (step S830).
When the number of registrations is 1, assuming that the node registered in the row of the server 120 in the registration table 207 is the node 122, the change request generation unit 206 changes the child of the server 120 from the branching device 2 to the node 122. A change request instructing to change is generated (step S835), and the packet transmission unit 201 transmits the change request to the server 120 (step S840).
Note that if it is determined in step S810 that the row of the server 120 that is the destination of the stop request does not exist in the registration table 207, if the source 121 does not exist in the row of the server 120 in the registration table 207, or If it is determined in step S825 that the number of registrations in the server 120 row of the registration table 207 is greater than 1, the process ends.

Finally, a case where a change request is received will be described with reference to FIG. In step S615 of FIG. 13, the packet type determination unit 202 determines that the received packet is a change request. The change request destination server is the server 160, the change destination node is the node 161, and the change source node is the node 162. The registration status determination unit 203 determines whether or not the row of the server 160 exists in the registration table 207 (step S910). If there is a row for the server 160 in the registration table 207, the registration status determination unit 203 checks whether the node 162 is registered as a child in the row for the server 160 in the registration table 207 (step S915). If the node 162 is registered as a child in the row of the server 160 in the registration table 207, the registration operation unit 205 changes the node 162 recorded in the row of the server 160 in the registration table 207 to the node 161. The process is terminated (step S920).
In step S910, if there is no row for server 160 in registration table 207, or if node 162 is not registered as a child in the row for server 160 in registration table 207 in step S915, the processing ends.

  As described above, the server 1 also operates in the same manner as in FIGS. 13 to 16 described above. At this time, the packet reception unit 200, the packet transmission unit 201, the packet type determination unit 202, the registration status determination unit 203, the registration operation unit 205, and the registration table 207 of the branching device 2 are the packet reception unit 100 and the packet of the server 1, respectively. It can be read as transmission unit 101, packet type determination unit 102, registration status determination unit 103, registration operation unit 105, and registration table 107. However, the server 1 does not perform steps S735, S740, and S745 in FIG. 13 and steps S830, S835, and S840 in FIG.

  According to the embodiment described above, in the multicast distribution system in which the branching device that branches the data distributed by multicast captures the reception request from the client to the server to construct the multicast distribution route, the server to the client When it is not necessary to branch the data in the branching device for the data packet transmitted by multicasting, it is possible to avoid the branching device performing the relay process for branching the data packet. As a result, the load on the branching device can be reduced and the performance of data distribution can be improved.

  Note that the packet receiving unit 100, the packet transmitting unit 101, the packet type determining unit 102, the registration status determining unit 103, the registration operation unit 105, and the recording device that records the registration table 107 and the branching device 2 of the server 1 shown in FIG. Packet receiving unit 200, packet transmitting unit 201, packet type determining unit 202, registration status determining unit 203, registration operation unit 205, change request generating unit 206, recording device for recording registration table 207, and client 4, 5 is recorded on a computer-readable recording medium, and a program recorded on the recording medium is read into a computer system and executed, thereby executing the server 1 and the branching apparatus of the present embodiment. 2 and clients 4 and 5 can be realized. The computer system here includes an OS and hardware such as peripheral devices.

Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  The embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiments, and includes designs and the like that do not depart from the gist of the present invention.

The block diagram which shows the structural example of one embodiment of this invention. The figure quoted in order to demonstrate operation | movement of the embodiment. The figure quoted in order to demonstrate operation | movement of the embodiment. The figure quoted in order to demonstrate operation | movement of the embodiment. The figure quoted in order to demonstrate operation | movement of the embodiment. The figure quoted in order to demonstrate operation | movement of the embodiment. The figure quoted in order to demonstrate operation | movement of the embodiment. The figure quoted in order to demonstrate operation | movement of the embodiment. The figure quoted in order to demonstrate operation | movement of the embodiment. The operation | movement sequence diagram quoted in order to demonstrate operation | movement of the embodiment. The operation | movement sequence diagram quoted in order to demonstrate operation | movement of the embodiment. The block diagram which expanded and showed the internal structure of the branching device and server of the embodiment. The flowchart quoted in order to demonstrate operation | movement of the branch apparatus of the embodiment. The flowchart quoted in order to demonstrate operation | movement of the branch apparatus of the embodiment. The flowchart quoted in order to demonstrate operation | movement of the branch apparatus of the embodiment. The flowchart quoted in order to demonstrate operation | movement of the branch apparatus of the embodiment. The block diagram which shows the structure of the conventional multicast data communication system. The figure quoted in order to demonstrate operation | movement of the conventional multicast data communication system. The figure quoted in order to demonstrate operation | movement of the conventional multicast data communication system. The figure quoted in order to demonstrate operation | movement of the conventional multicast data communication system. The figure quoted in order to demonstrate operation | movement of the conventional multicast data communication system. The figure quoted in order to demonstrate operation | movement of the conventional multicast data communication system. The figure quoted in order to demonstrate operation | movement of the conventional multicast data communication system. The figure quoted in order to demonstrate operation | movement of the conventional multicast data communication system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Server 2 ... Branching device 3, 4 ... Client 5, 6, 107, 207 ... Registration table 100, 200 ... Packet receiving part 101, 201 ... Packet transmission part 102, 202 ... Packet type discrimination | determination part 103, 203 ... Registration status Discriminating unit 105, 205 ... Registration operation unit 206 ... Change request generating unit

Claims (12)

One or more servers and two or more clients are connected via one or more branching devices,
When the branching device is provided with a registration table for recording one server and a transmission destination of data transmitted from the server, and is on a communication path between the client and the server, reception of data transmitted to the server Capture the request, register the client or other branching device of the reception request as a data transmission destination corresponding to the destination server of the reception request in the registration table provided inside, and send to the destination server Build a tree-like distribution route rooted at the server by repeating a series of operations for generating and transmitting a new reception request until the reception request reaches the destination server,
When the server is registered in an internal registration table and transmits data to a transmission destination corresponding to the server, the branching device that has received the data refers to the internal registration table, and In a multicast data communication system that repeats a series of operations for copying and transmitting the data to a delivery destination corresponding to a transmission source server until the data reaches all clients.
The branching device is:
Capture a reception request transmitted to a server by a client or another branch device, and correspond to the destination server of the reception request, and internally use the client or other branch device that is the transmission source of the reception request as a transmission destination A registration operation unit for registering in the registration table;
As a result of registration, if the number of transmission destinations is other than 2, the reception request is made transparent. If the number of transmission destinations is 2, a change request for requesting to change the data transmission destination to its own branching device is issued. A change request generator for generating and transmitting to the destination server;
When data transmitted from a server is received and the number of transmission destinations of data corresponding to the server registered in the registration table is 1, the data is transparent, and the number of transmission destinations is 2 or more Includes a packet transmission unit that duplicates and transmits the data to the client or other branch device of the transmission destination,
The server
When the reception request is received, the client or branching device that is the transmission source of the reception request is written in the registration table provided internally as a transmission destination corresponding to itself, and when the change request is received, A registration operation unit for changing a transmission destination corresponding to itself to a transmission destination designated by the change request;
A multicast data communication system. The registration operation unit of the branch device captures the change request transmitted to the server by the other branch device, and determines the transmission destination corresponding to the destination server of the change request in the registration table provided therein by the change request. Change to the specified destination,
The multicast data communication system according to claim 1. One or more servers and two or more clients are connected via one or more branching devices,
When the branching device is provided with a registration table for recording one server and a transmission destination of data transmitted from the server, and is on a communication path between the client and the server, reception of data transmitted to the server Capture the request, register the client or other branching device of the reception request as a data transmission destination corresponding to the destination server of the reception request in the registration table provided inside, and send to the destination server Build a tree-like distribution route rooted at the server by repeating a series of operations for generating and transmitting a new reception request until the reception request reaches the destination server,
When the server is registered in an internal registration table and transmits data to a transmission destination corresponding to the server, the branching device that has received the data refers to the internal registration table, and In a multicast data communication system that repeats a series of operations for copying and transmitting the data to a delivery destination corresponding to a transmission source server until the data reaches all clients.
The branching device is:
The client that is the transmission source of the stop request from the transmission destination corresponding to the destination server of the stop request within the registration table that captures the stop request of the data transmitted to the server by the client or another branch device Or a registration operation unit for deleting other branch devices;
As a result of the deletion, if the number of transmission destinations is 0 , the stop request is transmitted as it is to the server, and if the number of transmission destinations is 1, the stop of capturing the data transmission destination from its own branching device A change that generates a change request that requests a change to a client or other branch device registered in the registration table other than the client or other branch device that is the source of the request, and transmits the change request to the destination server A request generator;
When data transmitted from a server is received and the number of transmission destinations of data corresponding to the server registered in the registration table is 1, the data is transparent, and the number of transmission destinations is 2 or more Includes a packet transmission unit that duplicates and transmits the data to the client or other branch device of the transmission destination,
The server
When the stop request is received, the client or branch device that is the transmission source of the stop request is deleted from the transmission destination corresponding to itself in the registration table provided therein, and the registration table is received when the change request is received. A registration operation unit for changing the transmission destination corresponding to itself to the transmission destination specified by the change request,
A multicast data communication system. The registration operation unit of the branch device captures the change request transmitted to the server by the other branch device, and determines the transmission destination corresponding to the destination server of the change request in the registration table provided therein by the change request. Change to the specified destination,
The multicast data communication system according to claim 3. One or more servers and two or more clients are connected via one or more branching devices,
When the branching device is provided with a registration table for recording one server and a transmission destination of data transmitted from the server, and is on a communication path between the client and the server, reception of data transmitted to the server Capture the request, register the client or other branching device of the reception request as a data transmission destination corresponding to the destination server of the reception request in the registration table provided inside, and send to the destination server Build a tree-like distribution route rooted at the server by repeating a series of operations for generating and transmitting a new reception request until the reception request reaches the destination server,
When the server is registered in an internal registration table and transmits data to a transmission destination corresponding to the server, the branching device that has received the data refers to the internal registration table, and A branching device used in a multicast data communication system that repeats a series of operations for copying and transmitting the data to a delivery destination corresponding to a transmission source server until the data reaches all clients,
Capture a reception request transmitted to a server by a client or another branch device, and correspond to the destination server of the reception request, and internally use the client or other branch device that is the transmission source of the reception request as a transmission destination A registration operation unit for registering in the registration table;
As a result of registration, if the number of transmission destinations is other than 2, the reception request is made transparent. If the number of transmission destinations is 2, a change request for requesting to change the data transmission destination to its own branching device is issued. A change request generator for generating and transmitting to the destination server;
When data transmitted from a server is received and the number of transmission destinations of data corresponding to the server registered in the registration table is 1, the data is transparent, and the number of transmission destinations is 2 or more A packet transmission unit that replicates and transmits the data to the client or other branch device of the transmission destination;
A branching device comprising: The registration operation unit captures a change request transmitted to a server by another branch device, and designates a transmission destination corresponding to a destination server of the change request in the registration table provided therein by the change request. Change to destination,
The branching device according to claim 5. One or more servers and two or more clients are connected via one or more branching devices,
When the branching device is provided with a registration table for recording one server and a transmission destination of data transmitted from the server, and is on a communication path between the client and the server, reception of data transmitted to the server Capture the request, register the client or other branching device of the reception request as a data transmission destination corresponding to the destination server of the reception request in the registration table provided inside, and send to the destination server Build a tree-like distribution route rooted at the server by repeating a series of operations for generating and transmitting a new reception request until the reception request reaches the destination server,
When the server is registered in an internal registration table and transmits data to a transmission destination corresponding to the server, the branching device that has received the data refers to the internal registration table, and A branching device used in a multicast data communication system that repeats a series of operations for copying and transmitting the data to a delivery destination corresponding to a transmission source server until the data reaches all clients,
The client that is the transmission source of the stop request from the transmission destination corresponding to the destination server of the stop request within the registration table that captures the stop request of the data transmitted to the server by the client or another branch device Or a registration operation unit for deleting other branch devices;
As a result of the deletion, if the number of transmission destinations is 0 , the stop request is transmitted as it is to the server, and if the number of transmission destinations is 1, the stop of capturing the data transmission destination from its own branching device A change that generates a change request that requests a change to a client or other branch device registered in the registration table other than the client or other branch device that is the source of the request, and transmits the change request to the destination server A request generator;
When data transmitted from a server is received and the number of transmission destinations of data corresponding to the server registered in the registration table is 1, the data is transparent, and the number of transmission destinations is 2 or more A packet transmission unit that replicates and transmits the data to the client or other branch device of the transmission destination;
A branching device comprising: The registration operation unit captures a change request transmitted to a server by another branch device, and designates a transmission destination corresponding to a destination server of the change request in the registration table provided therein by the change request. Change to destination,
The branching device according to claim 7. One or more servers and two or more clients are connected via one or more branching devices,
When the branching device is provided with a registration table for recording one server and a transmission destination of data transmitted from the server, and is on a communication path between the client and the server, reception of data transmitted to the server Capture the request, register the client or other branching device of the reception request as a data transmission destination corresponding to the destination server of the reception request in the registration table provided inside, and send to the destination server Build a tree-like distribution route rooted at the server by repeating a series of operations for generating and transmitting a new reception request until the reception request reaches the destination server,
When the server is registered in an internal registration table and transmits data to a transmission destination corresponding to the server, the branching device that has received the data refers to the internal registration table, and A computer program used for a branching device in a multicast data communication system that repeats a series of operations for copying and transmitting the data to a delivery destination corresponding to a transmission source server until the data reaches all clients,
Capture a reception request transmitted to a server by a client or another branch device, and correspond to the destination server of the reception request, and internally use the client or other branch device that is the transmission source of the reception request as a transmission destination Registering in the registration table comprising:
As a result of registration, if the number of transmission destinations is other than 2, the reception request is made transparent. If the number of transmission destinations is 2, a change request for requesting to change the data transmission destination to its own branching device is issued. Generating and transmitting to the destination server;
When data transmitted from a server is received and the number of transmission destinations of data corresponding to the server registered in the registration table is 1, the data is transparent, and the number of transmission destinations is 2 or more A step of replicating and transmitting the data to the client or other branch device of the transmission destination;
A computer program for causing a computer to execute. A step of capturing a change request transmitted to a server by another branch device, and changing a transmission destination corresponding to the destination server of the change request in the registration table provided therein to a transmission destination specified by the change request When,
The computer program according to claim 9, further comprising: One or more servers and two or more clients are connected via one or more branching devices,
When the branching device is provided with a registration table for recording one server and a transmission destination of data transmitted from the server, and is on a communication path between the client and the server, reception of data transmitted to the server Capture the request, register the client or other branching device of the reception request as a data transmission destination corresponding to the destination server of the reception request in the registration table provided inside, and send to the destination server Build a tree-like distribution route rooted at the server by repeating a series of operations for generating and transmitting a new reception request until the reception request reaches the destination server,
When the server is registered in an internal registration table and transmits data to a transmission destination corresponding to the server, the branching device that has received the data refers to the internal registration table, and A computer program used for a branching device in a multicast data communication system that repeats a series of operations for copying and transmitting the data to a delivery destination corresponding to a transmission source server until the data reaches all clients,
The client that is the transmission source of the stop request from the transmission destination corresponding to the destination server of the stop request within the registration table that captures the stop request of the data transmitted to the server by the client or another branch device Or a step of deleting another branch device;
As a result of the deletion, if the number of transmission destinations is 0 , the stop request is transmitted as it is to the server, and if the number of transmission destinations is 1, the stop of capturing the data transmission destination from its own branching device A step of generating a change request for requesting a change to a client or other branch device registered in the registration table other than the client or other branch device that is a transmission source of the request, and transmitting the change request to the destination server When,
When data transmitted from a server is received and the number of transmission destinations of data corresponding to the server registered in the registration table is 1, the data is transparent, and the number of transmission destinations is 2 or more A step of replicating and transmitting the data to the client or other branch device of the transmission destination;
A computer program for causing a computer to execute. A step of capturing a change request transmitted to a server by another branch device, and changing a transmission destination corresponding to the destination server of the change request in the registration table provided therein to a transmission destination specified by the change request When,
The computer program according to claim 11, further comprising:

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