JP2006197470A - Data stream distribution system, node, distribution route deciding apparatus, and distribution route deciding program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a distribution interruption time to the minimum by executing quick countermeasures if a transmission failure occurs in a transmission path in a data stream distribution system for distributing a data stream. <P>SOLUTION: Multicast distribution of data streams is executed from data stream distribution terminals G1-G3 to nodes 10-40 connected to data stream receiving terminals R1-R8 which may request the reception of data stream. Also, each node stores distribution route information of both a normal case and a case where transmission failure occurs, and when a transmission failure occurs, quick switching to a distribution route information corresponding to a case of occurrence of transmission failure is executed to continue distribution by an alternative distribution route. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a data stream distribution system that distributes a data stream to a specific terminal.

  As a countermeasure technique when a transmission failure occurs in a communication network, for example, by using a trouble ticket search, it is possible to refer to a past failure history so that a solution to the failure can be quickly obtained. (Patent Document 1), or network configuration information and operation statistics information are made into a database, and there is a method (Patent Document 2) that attempts to automatically display failure countermeasure contents using this database.

  Failures in the communication network are accidental and unpredictable, and the communication status via the network changes with time, so it is difficult to take direct measures. Therefore, in reality, as seen in the above-mentioned patent document, indirect such as failure countermeasure management and failure analysis support in which the best method is derived by referring to the past history and database after the failure has occurred. To enhance various countermeasures.

  In recent years, proposals have been made to use multicast transmission when distributing a data stream including audio data and video data via an IP network. Multicast transmission is a method of broadcasting data streams to a large number of terminals. Since the same data stream is distributed along different transmission paths, the communication mode is more redundant than unicast distribution. It can be said to be an advantageous configuration in terms of fault countermeasures.

  As a communication protocol for data stream distribution using multicast, there is a protocol specification by IETF (see Non-Patent Document 1), and the countermeasure for failure is also defined in this communication protocol for multicast distribution. The contents of the countermeasures for failure conforming to this protocol specification are as follows.

  First, when a data stream receiving terminal A requests a data stream b for data stream distribution terminal B, a data stream b distribution request message is transmitted from data stream receiving terminal A to data stream distribution terminal B. The When this distribution request message is relayed between nodes and reaches data stream distribution terminal B, transmission of data stream b from data stream distribution terminal B to data stream distribution terminal A is started. At this time, a distribution table of the data stream b from the data stream distribution terminal B to the data stream reception terminal A is configured by configuring a routing table in each node along the relay path of the distribution request message.

  Such a configuration of the routing table is performed using a routing protocol, and a delivery route with the shortest route from the data stream receiving terminal to the data stream delivery terminal is always constructed.

  When a transmission failure occurs in the transmission path on the data stream distribution path, a node closer to the data stream receiving terminal (that is, the distribution of the data stream) among the nodes at both ends connected to the transmission path. The node located further downstream in (1) detects this transmission failure. After that, the node that detected the transmission failure transmits a data stream reception request similar to the above to the data stream distribution terminal, and this reception request message is relayed again between the nodes and reaches the corresponding data stream distribution terminal. As a result, transmission of the data stream is resumed.

  In this way, in a data stream distribution system using multicast transmission, a downstream node that detects a failure resends a data stream reception request, and a new distribution route is constructed using a routing protocol. The data stream can be received later.

JP-A-6-326751 JP 2003-152721 A IETF protocol specification RFC 2362 (Protocol Independent Multicast-Sparse Mode (PIM-SM))

  As described above, in a stream distribution system using multicast transmission, if any transmission failure occurs in the transmission path on the data stream distribution path, the distribution path is reconstructed after the transmission failure is detected. Done.

  However, since the reconstruction of such a distribution route is performed for each data stream using a sequential routing protocol, the distribution routes of all the data streams distributed via the transmission path in which the transmission failure has occurred are re-established. It takes a long time to build. Therefore, in the meantime, distribution of the data stream has to be stopped.

  The present invention has been made in view of the above circumstances. Even when a transmission failure occurs, the present invention is capable of quickly constructing an alternative delivery path and minimizing the interruption time of data stream delivery. An object of the present invention is to provide a data stream distribution system.

  The data stream distribution system of the present invention is a data stream distribution system for distributing a data stream to a specific terminal, wherein a network configured by connecting a plurality of nodes having a routing function by a plurality of transmission paths, and the node A data stream distribution terminal that distributes the data stream via the network and a data stream reception terminal that is connected to the node and receives a data stream distributed from the data stream distribution terminal via the network The data stream distribution terminal distributes the data stream to a node connected to the terminal regardless of whether or not the distribution request is made, and the node may request reception of the data stream. The data stream receiving terminal having A distribution path information storage unit for storing distribution path information indicating a distribution path for distributing the data stream to a node connected to a terminal capable of receiving the data stream; and a data stream distributed from the data stream distribution terminal Distribution means for distributing the data stream according to the distribution path information, transmission means for transmitting the data stream distributed through the distribution path to the receivable terminal in response to a data stream reception request from the receivable terminal, Transmission failure detecting means for detecting a transmission failure occurring in a plurality of transmission lines, and the distribution route information is the distribution route (hereinafter referred to as the distribution route in the system configuration when no transmission failure occurs in the plurality of transmission lines). First distribution path information indicating a first distribution path) and a system when a transmission failure occurs in the plurality of transmission paths. Second distribution route information indicating the distribution route (hereinafter referred to as a second distribution route) in the configuration, and the distribution unit is configured to perform the first distribution when a transmission failure is not detected by the transmission failure detection unit. The distribution is performed according to route information, and when a transmission failure is detected by the transmission failure detection means, the distribution is performed according to the second distribution route information.

  With this configuration, since the distribution path of the data stream distributed from the data stream distribution terminal is fixed, the optimal distribution path can be selected, and the data stream can be distributed with high quality. In addition, since there is always a data stream that may be requested to be received from the receivable terminal in the node connected to the receivable terminal, the data stream can be quickly distributed. Even when a data stream desired to be received is switched to another data stream, the switching can be performed quickly. In addition, since each node stores the first distribution route information and the second distribution route information, even if a transmission failure occurs in the transmission line, the distribution route is changed to another distribution route corresponding to the transmission failure. You can switch instantly.

  The data stream distribution system of the present invention may request system configuration information indicating a system configuration of the data stream distribution system, and reception of the data stream distributed from the data stream distribution terminal and the data stream distribution terminal. Based on the information associated with the receivable terminal and the data amount information indicating the data amount of the data stream to be distributed, the first distribution route in the system configuration when the transmission failure has not occurred A delivery route determination device for determining the second delivery route in the system configuration when the transmission failure occurs, and a delivery route for delivering the delivery route information indicating the determined delivery route to the plurality of nodes An information distribution device.

  With this configuration, it is possible to determine a distribution route corresponding to a case where no transmission failure has occurred and a distribution route corresponding to a case where a transmission failure has occurred, and distribute it to each node.

  In the data stream distribution system according to the present invention, the distribution path determination device uses the first distribution path and the second distribution path, and the total data amount of the data stream flowing through the transmission path is the transmission capacity of the transmission path. To fit in.

  With this configuration, it is possible to prevent data streams from being concentrated on a specific transmission path, and to improve communication quality.

  The node of the present invention includes a network configured by connecting a plurality of nodes having a routing function by a plurality of transmission paths, a data stream distribution terminal connected to the node and distributing the data stream via the network, The data stream receiving system connected to the node and comprising a data stream receiving terminal for receiving a data stream distributed from the data stream distributing terminal via the network, wherein the node receives the data stream Distribution path information storage means for storing distribution path information indicating a distribution path for distributing the data stream to a node connected to the data stream receiving terminal (hereinafter referred to as a receivable terminal) And the data stream distribution terminal The data stream distributed from the distribution path according to the distribution path information, and the data stream distributed through the distribution path is transmitted to the receivable terminal in response to a data stream reception request from the receivable terminal. And a transmission fault detecting means for detecting a transmission fault occurring in the plurality of transmission paths, and the distribution path information is a system configuration when no transmission fault occurs in the plurality of transmission paths. First delivery route information indicating the delivery route (hereinafter referred to as a first delivery route), and the delivery route (hereinafter referred to as a second delivery route) in a system configuration when a transmission failure occurs in the plurality of transmission routes. Second distribution route information indicating the first distribution route information when the transmission failure is not detected by the transmission failure detection unit. Accordingly performs the distribution, if the transmission failure is detected by the transmission failure detector performs the distribution in accordance with the second delivery path information.

  With this configuration, since the distribution path of the data stream distributed from the data stream distribution terminal is fixed, the optimal distribution path can be selected, and the data stream can be distributed with high quality. In addition, since there is always a data stream that may be requested to be received from the receivable terminal in the node connected to the receivable terminal, the data stream can be quickly distributed. Even when a data stream desired to be received is switched to another data stream, the switching can be performed quickly. In addition, since each node stores the first distribution route information and the second distribution route information, even if a transmission failure occurs in the transmission line, the distribution route is changed to another distribution route corresponding to the transmission failure. You can switch instantly.

  The node of the present invention requests that the first distribution path receives system configuration information indicating a system configuration of the data stream distribution system and a data stream distributed from the data stream distribution terminal and the data stream distribution terminal. Is determined in the system configuration when the transmission failure does not occur, based on information that associates a receivable terminal that is likely to perform and data amount information that indicates the data amount of the data stream to be distributed. The second distribution path requests reception of system configuration information indicating a system configuration of the data stream distribution system and a data stream distributed from the data stream distribution terminal and the data stream distribution terminal. Information associated with possible receivable terminals and the distribution Based on the data amount information indicating a data quantity of Rubeki data stream, in which the transmission failure has been determined in the system configuration as they occur.

  The node according to the present invention is such that the first distribution path and the second distribution path are determined so that a total amount of data of a data stream flowing through the transmission path is within a transmission capacity of the transmission path. .

  With this configuration, it is possible to prevent data streams from being concentrated on a specific transmission path, and to improve communication quality.

  The delivery route determination device of the present invention is a delivery route determination device that determines the delivery route of the delivery route information stored in the node, the system configuration information indicating a system configuration of the data stream delivery system, Information that associates a data stream distribution terminal with a receivable terminal that may request reception of a data stream distributed from the data stream distribution terminal, and a data amount indicating the data amount of the data stream to be distributed Based on the information, the first distribution path is determined in the system configuration when the transmission failure has not occurred, and the second distribution path is determined in the system configuration when the transmission failure has occurred.

  With this configuration, it is possible to determine a distribution route corresponding to a case where no transmission failure has occurred and a distribution route corresponding to a case where a transmission failure has occurred, and distribute it to each node.

  The distribution route determination apparatus according to the present invention determines the first distribution route and the second distribution route so that a total amount of data streams of data streams flowing through the transmission line can be accommodated in a transmission capacity of the transmission line.

  With this configuration, it is possible to prevent data streams from being concentrated on a specific transmission path, and to improve communication quality.

  The distribution route determination program of the present invention is a program for causing a computer to function as the distribution route determination device.

  According to the present invention, even when a transmission failure occurs, a highly reliable data stream distribution system that can quickly construct an alternative distribution path and minimize the interruption time of data stream distribution is provided. be able to.

  Embodiments of the present invention will be described with reference to the drawings.

First, features of the data stream distribution system of this embodiment will be briefly described.
In the data stream distribution system of the present embodiment, all data stream receiving terminals that may request reception of the data stream are identified in advance, and the data stream is transmitted to the nodes connected to each of the data stream receiving terminals. Adopt a communication method to deliver

  The identification of all the data stream receiving terminals that may request reception of the data stream can be estimated in consideration of the reception reservation status of the data stream and the past performance (reception history information). For example, pay-per-view content viewing requires a reservation in advance, and the viewability of the content of each data stream receiving terminal can be predicted from the reservation status. In addition, it is possible to estimate the content viewing possibility of each data stream receiving terminal in consideration of past viewing results.

  From this point of view, the data stream distribution system according to the present embodiment uniquely identifies all data stream receiving terminals that may request reception of the data stream, and is connected to all the data stream receiving terminals. For this, the data stream is distributed in advance.

  The data stream distribution system having such characteristics will be specifically described below.

FIG. 1 is a diagram showing a schematic configuration of a data stream distribution system for explaining an embodiment of the present invention.
A data stream distribution system 100 shown in FIG. 1 includes a core network (core network) configured by connecting a plurality of nodes 10, 20, 30, and 40 having a packet routing function through transmission lines L12, L13, L14, L24, and L34. : A network that forms the core of the IP network infrastructure, whether it is a dedicated network or a general-purpose network) and data stream distribution terminals G1, G2, G3 that distribute data streams such as video data and audio data via the core network , Data stream receiving terminals R1, R2, R3, R4, R5, R6, R7, R8 that receive data streams distributed from the data stream distributing terminals G1, G2, G3 via the core network, and data in the core network Stream is multi The distribution route determination device 50 that determines the distribution route (multicast route) at the time of the broadcast distribution, and the distribution route information (routing table) that indicates the distribution route determined by the distribution route determination device 50 to each of the nodes 10 to 40 A distribution route information distribution device 60 for distribution;

  Each of the nodes 10 to 40 is a communication device that supports multicast transmission, and corresponds to a router, a packet switch (high-speed, large-capacity switch, etc.), and the like. The nodes 10 to 40 are connected to each other as illustrated by transmission lines L12 to L34. The transmission capacity of each transmission path is, for example, 10 Mbit / second.

  The data stream distribution terminals G1 to G3 include, for example, a camera for live broadcasting of a singer concert (including an IP communication device that multicasts data captured by this camera in real time) and a content distribution server that distributes movie content It is. The data stream distribution terminals G1 to G3 distribute the data stream possessed by the terminal to nodes connected to the terminal regardless of whether or not there is a distribution request.

  The data stream receiving terminals R1 to R8 are, for example, monitor devices (with an IP packet transmission / reception function) for viewing a singer concert.

  Data stream distribution terminals G1, G2, and G3 are connected to the node 10 via, for example, a LAN (in the figure, this LAN is drawn with a straight line. The same applies hereinafter).

  Data stream receiving terminals R1 and R2 are connected to the node 20 via a LAN.

  Data stream receiving terminals R6, R7, and R8 are connected to the node 30 via a LAN.

  Data stream receiving terminals R3, R4, and R5 are connected to the node 40 via a LAN.

FIG. 2 is a block diagram showing an internal configuration of each node shown in FIG.
As shown in FIG. 2, each of the nodes 10 to 40 transmits and receives a data stream using a communication port connected to another node, a data stream distribution terminal, and a data stream receiving terminal (claims). (Corresponding to the distribution means and transmission means in the range), the control unit 84 for controlling the entire node, and the storage unit 86 (corresponding to the distribution route information storage means in the claims) such as ROM, RAM, and hard disk. Prepare.

  The storage unit 86 may request reception of the data stream distributed from each data stream distribution terminal G1 to G3 from a node connected to each data stream distribution terminal G1 to G3. Distribution path information indicating a distribution path for distributing to a node connected to a data stream receiving terminal (hereinafter referred to as a receivable terminal) is stored. Further, the storage unit 86 stores a data stream distributed to the own node.

  The distribution route information includes the first distribution route information indicating the first distribution route corresponding to the case where no transmission failure has occurred in each of the transmission lines L12 to L34, and the transmission failure in each of the transmission lines L12 to L34. Second distribution route information indicating a second distribution route corresponding to the occurrence of the second distribution route is included.

  The control unit 84 is mainly configured by a processor that operates according to a predetermined program. The control unit 84 includes a distribution path information management unit 84a, a distribution control unit 84b, a transmission control unit 84c, and a transmission failure detection unit 84d.

  The transmission failure detection unit 84d detects that a transmission failure has occurred in each of the transmission lines L12 to L34. The detection of this transmission failure is performed by receiving a transmission failure detection signal (a signal indicating in which transmission path a transmission failure has occurred) distributed from another node or the distribution route information distribution device 60 via the transmission / reception unit 82. To detect.

  In addition to receiving the transmission failure detection signal, the transmission failure detection unit 84d detects the disconnection of the received signal from the other node connected to the transmission path connected to the own node, and periodically exchanges with the other node. A transmission failure can also be detected by a method such as detection of an unreceived communication confirmation packet. When a transmission failure is detected by this method, the transmission failure detection unit 84d causes the transmission failure detection signal indicating that to be transmitted to another node via the transmission / reception unit 82. Note that the transmission failure detection unit 84d may once transmit the transmission failure detection signal to the distribution path information distribution device 60 and distribute it to each node from here.

  The delivery route information management unit 84a receives the first delivery route information and the second delivery route information from the delivery route information delivery device 60 via the transmission / reception unit 82, and stores them in the storage unit 86 for management.

  The distribution control unit 84b receives the data stream distributed from the data stream distribution terminals G1 to G3 via the transmission / reception unit 82, and when the final destination of the received data stream is its own node, the data The stream is stored in the storage unit 86. On the other hand, when the final destination of the received data stream is not the local node, the first delivery path information or the second delivery path information of the received data stream stored in the storage unit 86 is stored. The data stream is distributed from the transmitting / receiving unit 82 to other nodes.

  When the transmission failure is not detected by the transmission failure detection unit 84d in distributing the data stream, the distribution control unit 84b performs distribution according to the first distribution route information, and the transmission failure detection unit 84d performs the transmission failure. Is detected, the distribution is performed according to the second distribution route information.

  When a data stream reception request is made from any of the data stream receiving terminals connected to the own node, the transmission control unit 84c reads the requested data stream from the storage unit 86 in response to the reception request. Then, it is transmitted from the transmitting / receiving unit 82 to the requesting data stream receiving terminal.

  Returning to FIG. 1, a distribution route information distribution device 60 is connected to the node 10. The distribution route information distribution device 60 obtains distribution route information (first distribution route information and second distribution route information) indicating the distribution route in the core network of the data stream determined by the distribution route determination device 50. The data is distributed to the nodes 10 to 40 via the nodes 10 to 40 and the transmission lines L12 to L34.

  Distribution route information (first distribution route information and second distribution route information) indicating the distribution route determined by the distribution route determination device 50 is input to the distribution route information distribution device 60 online or offline.

FIG. 3 is a block diagram showing an internal configuration of the delivery route determination device shown in FIG.
The delivery route determination device 50 is, for example, a computer, and may request reception of each data stream delivery terminal G1 to G3 and a data stream delivered from each data stream delivery terminal G1 to G3, as shown in FIG. Information 62 associated with a certain reception request terminal, system configuration information indicating the system configuration of the data stream distribution system 100 (connection relationship of each component, transmission capacity of each transmission path L12 to L34, etc.), and each data stream A storage unit 64 such as a hard disk that stores data amount information indicating the data amount of each data stream distributed from the distribution terminals G1 to G3, and a distribution path of each data stream based on the information stored in the storage unit 64 And a delivery route determination unit 70 for determining one of them. Note that the storage unit 64 may be provided in an external server accessible from the distribution route determination device 50.

  In the present embodiment, as indicated by the information 62, the reception request terminal that may request reception of the data stream (hereinafter referred to as g1) distributed from the data stream distribution terminal G1 is the data stream reception terminal R1. Reception request terminals that are R8 and that may request reception of a data stream (hereinafter referred to as g2) distributed from the data stream distribution terminal G2 are the data stream reception terminals R1 to R5, and from the data stream distribution terminal G3 It is assumed that reception request terminals that may request reception of a distributed data stream (hereinafter referred to as g3) are data stream reception terminals R3 to R8.

The distribution route determination unit 70 is mainly configured by a processor that operates according to a distribution route determination program.
The distribution route determination unit 70 distributes each data stream to be distributed from a node connected to each data stream distribution terminal G1 to G3 to a node connected to a reception-compatible terminal corresponding to each data stream distribution terminal G1 to G3. A delivery route is determined based on the information 62, system configuration information, and data amount information.

  The distribution path determination unit 70 determines a distribution path (first distribution path) for each data stream in the system configuration when it is assumed that no transmission failure has occurred in each of the transmission paths L13 to L34. In the system configuration when it is assumed that a transmission failure has occurred in L13 to L34, the distribution path (second distribution path) of each data stream is determined. For the second distribution route, the number corresponding to all patterns of transmission failures that may occur in the transmission lines L13 to L34 is determined. For example, one second distribution route is determined in the system configuration when a transmission failure occurs in the transmission line L12, and one second distribution route is determined in the system configuration when a transmission failure occurs in the transmission lines L12 and L13. For example.

  In addition, it is preferable that the delivery route determination unit 70 determines the delivery route (the first delivery route and the second delivery route) to be an optimum one that can prevent a reduction in delivery quality of each data stream. . The delivery route determination unit 70 externally sends delivery route information (first delivery route information and second delivery route information) indicating delivery routes (first delivery route and second delivery route) of each determined data stream. Output to.

FIG. 4 is a block diagram showing an internal configuration of the delivery route information delivery apparatus shown in FIG.
The delivery route information delivery device 60 is, for example, a computer, and receives delivery route information (first delivery route information and second delivery route information) output from the delivery route determination device 50 as shown in FIG. And a distribution unit 67 that distributes distribution route information (first distribution route information and second distribution route information) input through the input interface 65 to each of the nodes 10 to 40 via the node 10. With. Note that the functions of the distribution route determination device 50 and the distribution route information distribution device 60 can be realized by the same computer.

A specific operation of the data stream distribution system 100 having the above configuration will be described.
In the present embodiment, as shown in the information 62 of FIG. 3, the data stream g1 distributed from the data stream distribution terminal G1 is transmitted to the data stream reception terminals R1 to R8, that is, all the data stream reception terminals in the system. There is a possibility that the data stream g2 distributed from the data stream distribution terminal G2 may be requested, and the data stream reception terminals R1 to R5 may be requested to receive the data stream g2 and distributed from the data stream distribution terminal G3. The received data stream g3 may be requested to be received at the data stream receiving terminals R3 to R8.

  Under such a premise, the distribution path determination device 50 determines the optimal first distribution path and second distribution path of the data streams g1 to g3 distributed from the data stream distribution terminals G1 to G3. .

  The distribution path determination device 50 includes a distribution path for distributing the data stream g1 from the node 10 to which the data stream distribution terminal G1 is connected to the nodes 20, 30, and 40 to which the data stream receiving terminals R1 to R8 are connected. The data stream distribution terminal G3 is connected to the distribution path for distributing the data stream g2 from the node 10 to which the data stream distribution terminal G2 is connected to the nodes 20 and 40 to which the data stream reception terminals R2 to R5 are connected. From the node 10 thus determined, three distribution paths are determined including a distribution path for distributing the data stream g3 to the nodes 30 and 40 to which the data stream receiving terminals R3 to R8 are connected.

  The distribution route determination device 50 determines the three distribution routes in both the system configuration when it is assumed that no transmission failure has occurred and the system configuration when it is assumed that a transmission failure has occurred. . The first delivery route as the three delivery routes is determined by one of the following methods (1) to (3) based on the information 62, the system configuration information, and the data amount information. The second distribution route as the three distribution routes is determined by the following method (1) based on the information 62, the system configuration information, and the data amount information.

  (1) In order to improve the distribution quality of a data stream, the distribution path determination device 50 sets each distribution path so that the total amount of data streams flowing through an arbitrary transmission path is within the transmission capacity of the transmission path. To decide. For example, if the data amount of each of the data streams g1 to g3 is “1” and the transmission capacity of each of the transmission paths L12 to L34 is “2”, the distribution path determination device 50 has three or more data in one transmission path. The above three delivery paths are determined so that the stream does not flow. By determining the distribution route in this way, the data stream is evenly distributed to each transmission path, and the occurrence of packet loss due to a large number of data streams concentrating on a certain transmission path is avoided. It is possible to improve the delivery quality of the data stream.

  (2) The distribution path determination device 50 adds the total transmission capacity (one transmission path) of the transmission lines L12 to L34 necessary for distribution of the data streams g1 to g3 in order to improve the distribution quality of the data stream. Each distribution path is determined so that the sum of the data amount of the data streams flowing through the transmission capacity of the transmission path multiplied by the transmission capacity of the transmission path is minimized. For example, when the data amount of each of the data streams g1 to g3 is “1” and the transmission capacity of each of the transmission paths L12 to L34 is “2”, the distribution path determination device 50 causes the data stream flowing through each of the transmission paths L12 to L34. The above three delivery routes are determined so that the value obtained by integrating the numbers of the above is minimized. By determining the distribution route in this way, it is possible to increase the use efficiency of network resources.

  (3) In order to improve the distribution quality of the data stream, the distribution path determination device 50 allows the total data amount of the data stream flowing through an arbitrary transmission path to be within the transmission capacity of the transmission path, and each data stream Each delivery route is determined so that the total transmission capacity of the transmission routes L12 to L34 necessary for delivery of g1 to g3 is minimized. For example, if the data amount of each of the data streams g1 to g3 is “1” and the transmission capacity of each of the transmission paths L12 to L34 is “2”, the distribution path determination device 50 has three or more data in one transmission path. The four distribution paths are determined so that the stream does not flow and the value obtained by integrating the number of data streams flowing through the transmission paths L12 to L34 is minimized. By determining the distribution path in this way, the data stream is evenly distributed to each transmission path, and the problem of packet loss due to a large number of data streams flowing in a certain transmission path is solved. It is possible to improve the delivery quality of the data stream. It is also possible to increase the use efficiency of network resources.

The three distribution paths (first distribution paths) determined by the method (1) in the system configuration assuming that no transmission failure has occurred in each of the transmission lines L12 to L34 are as follows, for example.
The data stream g1 is distributed from the node 10 to the node 40 via the transmission line L14, from the node 40 to the node 20 via the transmission line L24, and from the node 40 to the node 30 via the transmission line L34. .
The data stream g2 is distributed from the node 10 to the node 20 via the transmission line L12, and is distributed from the node 20 to the node 40 via the transmission line L24.
The data stream g3 is distributed from the node 10 to the node 30 via the transmission line L13, and is distributed from the node 30 to the node 40 via the transmission line L34.

Further, in the system configuration in which it is assumed that a transmission failure has occurred in the transmission line L14 for some reason (disconnection of the transmission line, disconnection of the transmission line and the node, etc.) among the transmission lines L12 to L34, the method of (1) The three distribution paths (second distribution paths) determined by (1) are as follows, for example.
The data stream g1 is distributed from the node 10 to the node 20 via the transmission line L12, distributed from the node 20 to the node 40 via the transmission line L24, and distributed from the node 40 to the node 30 via the transmission line L34. .
The data stream g2 is distributed from the node 10 to the node 20 via the transmission line L12, and is distributed from the node 20 to the node 40 via the transmission line L24.
The data stream g3 is distributed from the node 10 to the node 30 via the transmission line L13, and is distributed from the node 30 to the node 40 via the transmission line L34.

  FIG. 5 is a diagram illustrating a first distribution path of a data stream corresponding to a case where no transmission failure has occurred in each of the transmission paths L12 to L34 in the data stream distribution system illustrated in FIG. In FIG. 5, the data stream g1 distributed from the data stream distribution terminal G1 is indicated by a thick arrow, the data stream g2 distributed from the data stream distribution terminal G2 is indicated by a normal arrow, and the data stream distribution terminal G3 The distributed data stream g3 is indicated by a one-dot chain line arrow.

  FIG. 6 is a diagram illustrating a second distribution path of a data stream corresponding to a transmission failure in the transmission path L14 in the data stream distribution system illustrated in FIG. In FIG. 6, the data stream g1 distributed from the data stream distribution terminal G1 is indicated by a thick arrow, the data stream g2 distributed from the data stream distribution terminal G2 is indicated by a normal arrow, and the data stream distribution terminal G3 The distributed data stream g3 is indicated by a one-dot chain line arrow.

  When the delivery route determination device 50 determines the first delivery route and the second delivery route as shown in FIGS. 5 and 6, the first delivery route information and the second delivery route indicating the delivery route. Information is distributed from the distribution route information distribution device 60 to each of the nodes 10 to 40. The first distribution route information and the second distribution route information distributed to each of the nodes 10 to 40 are stored in the storage unit 86 of each of the nodes 10 to 40. As a result, the nodes 10 to 40 are in a state in which the first distribution route information and the second distribution route information of the data streams g1 to g3 are statically held. Routing is performed according to the one delivery route information or the second delivery route information.

Next, an operation when no transmission failure has occurred in each of the transmission lines L12 to L34 will be described.
From the data stream distribution terminal G1, the data stream g1 is distributed to the node 10 regardless of whether there is a distribution request for the data stream g1. Since no transmission failure has occurred in each of the transmission lines L12 to L34, the transmission failure detection unit 84d of each of the nodes 10 to 40 does not detect the transmission failure. Accordingly, each of the nodes 10 to 40 distributes the data stream g1 to the nodes 20, 30, and 40 through the first distribution route as shown in FIG. 5 according to the first distribution route information stored in the storage unit 86. To do.

  From the data stream distribution terminal G2, the data stream g2 is distributed to the node 10 regardless of whether there is a distribution request for the data stream g2. Since no transmission failure has occurred in each of the transmission paths L12 to L34, each of the nodes 10 to 40 follows the first distribution path information stored in the storage unit 86 and performs the first distribution as shown in FIG. The data stream g2 is distributed to the nodes 20 and 40 through the route.

  From the data stream distribution terminal G3, the data stream g3 is distributed to the node 10 regardless of whether there is a distribution request for the data stream g3. Since no transmission failure has occurred in each of the transmission paths L12 to L34, each of the nodes 10 to 40 follows the first distribution path information stored in the storage unit 86 and performs the first distribution as shown in FIG. The data stream g3 is distributed to the nodes 30 and 40 through the route.

  In this state, when a transmission failure occurs in the transmission line L14, the transmission failure is detected by the transmission failure detection unit 84d of at least one of the node 10 and the node 40. Then, at least one of the node 10 and the node 40 transmits a transmission failure detection signal to the other nodes 20 and 30. As a result, each of the nodes 10 to 40 detects that a transmission failure has occurred in the transmission line L14.

  Since each of the nodes 10 to 40 has detected that a transmission failure has occurred in the transmission line L14, the data stream g1 distributed from the data stream distribution terminal G1 is transmitted through the first distribution path as shown in FIG. In the second delivery route information stored in the storage unit 86, the second delivery route information as shown in FIG. 6 according to the second delivery route information corresponding to the case where the transmission failure occurs in the transmission line L14. Deliver to nodes 20, 30, and 40 via the delivery route.

  Similarly, each of the nodes 10 to 40 has a transmission failure of the data stream g2 distributed from the data stream distribution terminal G2 in the transmission line L14 in the second distribution path information stored in the storage unit 86. The distribution is performed to the nodes 20 and 40 through the second distribution route according to the second distribution route information corresponding to the case.

  Similarly, each of the nodes 10 to 40 has a transmission failure of the data stream g3 distributed from the data stream distribution terminal G3 in the transmission line L14 in the second distribution path information stored in the storage unit 86. The node is distributed to the nodes 30 and 40 through the second distribution route according to the second distribution route information corresponding to the case.

  As described above, in the data stream distribution system 100, each of the data streams g1 to g3 is connected to a data stream receiving terminal that may request reception of the data stream, regardless of whether a transmission failure occurs or not. It is always in a state of being delivered up to the node that has been sent.

  If each data stream receiving terminal R1 to R8 wants to receive a desired data stream, each data stream receiving terminal R1 to R8 transmits a data stream reception request message to the node connected to the terminal and receives it. Make a request. As described above, the data stream that may be requested to be received from each of the data stream receiving terminals R1 to R8 has already been distributed to the node that has received the reception request. Therefore, the node that has received this reception request can start transmission of the requested data stream from the port connected to the requesting data stream receiving terminal in response to this request. Thereby, a desired data stream is received in each of the data stream receiving terminals R1 to R8.

  Further, when the reception of the data stream received by each of the data stream receiving terminals R1 to R8 is to be stopped, each data stream receiving terminal R1 to R8 receives a reception stop request from the node connected to the own terminal. Send a message and request to stop receiving. Upon receiving this request, the node stops transmission of the data stream from the port connected to the requesting data stream receiving terminal.

  For example, in FIGS. 5 and 6, when the data stream receiving terminal R4 requests reception of the data stream g1, the data stream receiving terminal R4 requests the node 40 to receive the data stream g1. The data stream g1 is always distributed to the node 40. Therefore, the data stream receiving terminal R4 can receive the data stream g1 only by an operation in which the node 40 starts transmission of the data stream g1 from the port connected to the data stream receiving terminal R4.

  When the data stream receiving terminal R4 wants to receive the data stream g3 instead of the data stream g1, the data stream receiving terminal R4 requests the node 40 to stop receiving the data stream g1 that has already been received. I do. Thereby, the node 40 stops the transmission of the data stream g1 from the port connected to the data stream receiving terminal R4. Subsequently, when the data stream receiving terminal R4 requests the node 40 to receive the data stream g3, the data stream g3 is transmitted from the node 40 to the data stream receiving terminal R4 by the same procedure.

  Thus, according to the data stream distribution system 100, the data stream receiving terminals R1 to R8 that may request the reception of the data stream are connected to the data streams from all the data stream distribution terminals R1 to R8. Can create a situation where it is always distributed to the nodes. For this reason, it is possible to fix the distribution route of the data stream, which has been changing every moment in the conventional example, and to design the distribution route of the data stream in advance.

  Further, according to the data stream distribution system 100, the data stream from all the data stream distribution terminals R1 to R8 is connected to the data stream reception terminals R1 to R8 that may request reception of the data stream. Therefore, each data stream receiving terminal R1 to R8 receives the data stream immediately only by requesting reception of the desired data stream to the node connected to the terminal. It becomes possible. Similarly, reception can be stopped and reception can be switched immediately.

  Further, according to the data stream distribution system 100, it is possible to statically configure the distribution path of each data stream regardless of the reception status at each data stream receiving terminal. Since it is possible to determine an optimum value within the range of the transmission capacity of each transmission path, it is possible to prevent a decrease in distribution quality such as packet loss due to an excess of the transmission capacity of the transmission path.

  In addition, according to the data stream distribution system 100, when determining the distribution route of each data stream, the total transmission capacity of the transmission paths necessary for the distribution of all the data streams is as small as possible. It is also possible to determine a delivery route, and it is possible to realize delivery and switching of more data streams under a limited network configuration.

  In addition, according to the data stream distribution system 100, even when a transmission failure occurs in each of the transmission lines L12 to L34, the second distribution route determined in the system configuration assuming that the transmission failure has occurred is shown. Since the second distribution route information is stored in advance in each of the nodes 10 to 40, the data streams g1 to g3 can be distributed in accordance with the second distribution route information. Therefore, unlike the conventional case, when a transmission failure occurs, it is not necessary to reconstruct the distribution path of each data stream g1 to g3, so that the system can be quickly recovered and the data stream distribution interruption time is minimized. It becomes possible to limit to the limit.

  In addition, since the second distribution route information can be stored in each of the nodes 10 to 40 corresponding to any pattern of transmission failure, any transmission failure can be dealt with reliably. be able to.

  Further, according to the data stream distribution system 100, since an optimal distribution path is determined for the second distribution path so that the distribution quality of the data stream is not deteriorated, the data stream can be obtained even when a transmission failure occurs. Can prevent degradation of delivery quality.

  The present invention is useful in a data stream distribution system that distributes a data stream because a rapid countermeasure against a network transmission failure can be implemented.

The figure which shows schematic structure of the data stream delivery system for describing embodiment of this invention The block diagram which shows the internal structure of each node shown in FIG. The block diagram which shows the internal structure of the delivery route determination apparatus shown in FIG. The block diagram which shows the internal structure of the delivery route information delivery apparatus shown in FIG. The figure which showed the 1st delivery route of the data stream in the data stream delivery system shown in FIG. The figure which showed the 2nd delivery route of the data stream in the data stream delivery system shown in FIG.

Explanation of symbols

10 to 40 nodes 50 delivery route determination device 60 delivery route information delivery device G1 to G3 data stream delivery terminal R1 to R8 data stream receiving terminal L12, L13, L24, L34 transmission path

Claims (9)

A data stream distribution system for distributing a data stream to a specific terminal,
A network configured by connecting a plurality of nodes having a routing function by a plurality of transmission paths;
A data stream delivery terminal connected to the node and delivering the data stream via the network;
A data stream receiving terminal connected to the node and receiving a data stream distributed from the data stream distributing terminal via the network;
The data stream distribution terminal distributes the data stream to a node connected to the terminal regardless of the distribution request.
The node is a distribution path indicating a distribution path for distributing the data stream to a node connected to the data stream receiving terminal (hereinafter referred to as a receivable terminal) that may request reception of the data stream. In response to a data stream reception request from the receivable terminal, a distribution path information storage unit that stores information, a distribution unit that distributes a data stream distributed from the data stream distribution terminal according to the distribution path information, and A transmission means for transmitting a data stream distributed through a distribution path to the receivable terminal; and a transmission fault detection means for detecting a transmission fault that has occurred in the plurality of transmission paths,
The delivery route information includes first delivery route information indicating the delivery route (hereinafter referred to as a first delivery route) in a system configuration when a transmission failure has not occurred in the plurality of transmission routes, and the plurality of delivery routes. Second distribution route information indicating the distribution route (hereinafter referred to as second distribution route) in the system configuration when a transmission failure occurs in the transmission line,
The delivery means performs the delivery according to the first delivery path information when the transmission fault is not detected by the transmission fault detection means, and when the transmission fault is detected by the transmission fault detection means, the second A data stream distribution system that performs the distribution according to distribution route information. The data stream distribution system according to claim 1, wherein
Information associating system configuration information indicating a system configuration of the data stream distribution system with the data stream distribution terminal and a receivable terminal that may request reception of a data stream distributed from the data stream distribution terminal And the first delivery route in the system configuration when the transmission failure has not occurred, based on the data amount information indicating the data amount of the data stream to be delivered, and the transmission failure has occurred A delivery route determination device for determining the second delivery route in the system configuration at the time,
A data stream distribution system comprising: a distribution path information distribution apparatus that distributes the distribution path information indicating the determined distribution path to the plurality of nodes. The data stream distribution system according to claim 2, wherein
The distribution path determination device determines the first distribution path and the second distribution path so that a total amount of data streams of data streams flowing through the transmission path is within a transmission capacity of the transmission path. system. A network configured by connecting a plurality of nodes having a routing function by a plurality of transmission paths, a data stream distribution terminal connected to the node and distributing the data stream via the network, and connected to the node The node used in a data stream distribution system comprising a data stream receiving terminal for receiving a data stream distributed from the data stream distribution terminal via the network,
Stores distribution path information indicating a distribution path for distributing the data stream to a node connected to the data stream receiving terminal (hereinafter referred to as a receivable terminal) that may request reception of the data stream. A delivery route information storage means;
A distribution means for distributing the data stream distributed from the data stream distribution terminal according to the distribution route information;
In response to a data stream reception request from the receivable terminal, transmission means for transmitting the data stream distributed through the distribution route to the receivable terminal;
A transmission failure detecting means for detecting a transmission failure occurring in the plurality of transmission lines,
The delivery route information includes first delivery route information indicating the delivery route (hereinafter referred to as a first delivery route) in a system configuration when a transmission failure has not occurred in the plurality of transmission routes, and the plurality of delivery routes. Second distribution route information indicating the distribution route (hereinafter referred to as second distribution route) in the system configuration when a transmission failure occurs in the transmission line,
The delivery means performs the delivery according to the first delivery path information when the transmission fault is not detected by the transmission fault detection means, and when the transmission fault is detected by the transmission fault detection means, the second A node that performs the distribution according to the distribution route information. The node according to claim 4, wherein
The first distribution path may receive system configuration information indicating a system configuration of the data stream distribution system, and reception of a data stream distributed from the data stream distribution terminal and the data stream distribution terminal. Is determined in the system configuration when the transmission failure does not occur, based on the information that associates the possible terminals and the data amount information indicating the data amount of the data stream to be distributed,
The second distribution path may receive system configuration information indicating a system configuration of the data stream distribution system, and reception of a data stream distributed from the data stream distribution terminal and the data stream distribution terminal. A node that is determined in the system configuration when the transmission failure occurs, based on information that associates a possible terminal with data amount information that indicates a data amount of the data stream to be distributed. The node according to claim 5, wherein
The first distribution path and the second distribution path are nodes determined so that a total amount of data of a data stream flowing through the transmission path can be accommodated in a transmission capacity of the transmission path. A delivery route determination device for determining the delivery route of the delivery route information stored in the node according to claim 4,
Information associating system configuration information indicating a system configuration of the data stream distribution system with the data stream distribution terminal and a receivable terminal that may request reception of a data stream distributed from the data stream distribution terminal And the first delivery route in the system configuration when the transmission failure has not occurred, based on the data amount information indicating the data amount of the data stream to be delivered, and the transmission failure has occurred A delivery route determination device that determines the second delivery route in the system configuration at that time. The delivery route determination device according to claim 7,
A delivery path determination device that determines the first delivery path and the second delivery path so that a total amount of data of a data stream flowing through the transmission path is within a transmission capacity of the transmission path.   A distribution route determination program for causing a computer to function as the distribution route determination device according to claim 7 or 8.

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