JP4237196B2 - Message transmission method, message transmission program, and message transmission apparatus - Google Patents

Description

  The present invention relates to a program, an apparatus, and a method for providing a transport layer function on a virtual logical network. Specifically, the present invention relates to a physical network on a communication network such as a TCP / IP (Transmission Control Protocol / Internet Protocol) network. The present invention relates to a program, an apparatus, and a method for autonomously configuring a logical network having a tree structure that is not constrained by a general network configuration and enabling unicast communication and multicast communication on the logical network.

  Unicast communication (one-to-one communication) can be used without any problem in the conventional technology. On the other hand, with respect to multicast communication (one-to-n broadcast communication), the conventional technology has several problems. The prior art and its problems are shown below.

  In IP multicast (network layer), a network device such as a router needs to support IP multicast communication. In addition, there is a cost for setting and maintaining these network devices.

  In UDP broadcast (transport layer), only broadcast within a range depending on a physical network configuration such as a subnet unit can be performed (see, for example, Non-Patent Document 1).

  In broadcast communication (application layer) via a relay server, costs for introducing and maintaining the relay server are incurred. Moreover, it is difficult to cope with a failure of the relay server.

In a P2P (Peer to Peer) application (application layer) such as file sharing, a logical network is configured by connecting nodes in an ad hoc manner. Therefore, the network configuration becomes disordered, the communication efficiency is very poor, and it cannot be applied to real-time communication.
Takashi Takeshita et al. "Mastering TCP / IP Introduction 2nd Edition", Ohmsha, Ltd., May 25, 1998, page 83

  In the conventional system construction, the disadvantages of the prior art are accepted as inevitable, and a technique that matches the system requirements is selected and adopted.

  The present invention autonomously configures a logical network having a tree structure independent of a physical network configuration on a communication network such as a TCP / IP (Transmission Control Protocol / Internet Protocol) network, and performs unicast communication on the logical network. Another object is to provide a program, an apparatus, and a method that enable multicast communication.

  A first feature of the present invention is a multicast message transmission method in which a servant that has received a message has (1) presence / absence of an uplink in a logical network, the presence / absence of an uplink servant ID, presence / absence of a downlink, Storing the downlink servant ID; (2) passing the received message to a higher-level application; and (3) reading the presence / absence of the uplink, and if the uplink exists, the uplink And (4) reading the presence / absence of the downlink, and transmitting the message to the downlink when the downlink exists.

  According to a second aspect of the present invention, there is provided a unicast message transmission method in which a servant that has received a message is: (1) a self-servant ID, a partition, each slot included in the partition, an up-servant, If there is a down servant belonging to each slot, the step of storing the down servant, (2) reading the destination servant ID from the received message, (3) the destination servant ID and the own servant ID, And (4) when the destination servant ID and the own servant ID match, the step of passing the message to an upper application, and (5) the destination servant ID and the own servant ID match. If not, the destination servant ID A servant ID value is obtained and the servant ID value is compared with the partition. (5-1) If the servant ID value is outside the partition, the message is transmitted to the up-servant. ) If the servant ID value is in the partition, in addition to sending the message to the up-servant, the servant ID value is compared with each slot and the slot to which the servant ID value belongs Transmitting the message to the down servant.

  According to the first feature of the present invention, a multicast message can be transmitted regardless of the type of network device and the physical network configuration.

  According to the second feature of the present invention, a unicast message can be transmitted regardless of the type of network device and the physical network configuration.

  In the embodiment of the present invention, a logical network is configured using only TCP links. Therefore, a logical network can be configured regardless of the type of network device and the physical network configuration. In addition, this logical network has a tree structure and can perform efficient communication. In particular, the present invention can be applied to real-time communication that has been difficult with the conventional P2P technology.

  The logical network according to the embodiment of the present invention is configured autonomously in accordance with the joining / leaving of nodes. Therefore, costs such as management of configuration information become unnecessary. In addition, since the logical network is automatically reconstructed when a failure occurs, the fault tolerance is high.

(Definition of terms)
In order to describe embodiments of the present invention, the following terms are defined.

  As shown in FIG. 1A, a virtual node on the logical network is referred to as a “servant” 11. The application creates a servant and communicates through it.

  A servant that is a “seed” of the logical network is referred to as a “seed servant” 12. In order to construct a logical network, at least one seed servant must exist. The seed servant is the core of the logical network, and the logical network is configured by continuously connecting servants other than the seed servant around the seed servant.

  An identifier for uniquely identifying the servant is referred to as a “servant ID”. The servant ID can be composed of a physical network address (IP address and port number). In addition, information other than the address may be added to the physical network address.

  The servant ID mapped to a unique integer value of 0 or more is called a servant ID value. It is not necessary that reverse conversion from a servant ID value to a servant ID is possible. That is, the servant ID may not be obtained from the servant ID value.

  In the embodiment of the present invention, a logical network having a tree structure configured by servants and TCP links between servants is constructed.

  As shown in FIG. 1B, the link near the root as viewed from a certain servant (the central servant in FIG. 1B) is an uplink (UpLink) 14, and the link near the leaf is a downlink ( (DownLink) 15. Further, the servant of the uplink destination is called the up servant (UpServant) 16, and the servant of the downlink destination is called the down servant (DownServant) 17.

  In the embodiment of the present invention, the maximum number of downlinks for each servant is a default value. Hereinafter, this maximum number is expressed as N. In the following example, N is 10 unless otherwise specified.

(Partition and slot)
When a subtree is extracted, a range that covers the servant ID values of all servants included in the subtree is called a “partition”. The partition is managed and updated by the servant at the top of this subtree. A partition divided into N value ranges is called a “slot”.

  The apex servant assigns a downlink to each slot, and the servant at the end of the downlink manages the partition corresponding to the slot. At this time, adjustment is performed so that the number of downlinks in each slot is at most one.

(Calculation method)
The range defined by the minimum and maximum values is expressed as [minimum and maximum].

When the range of the servant ID value of the subtree is [vmin, vmax]
Nx × y ≤ vmin, vmax <Nx × (y + 1)
(x and y are integers x> 0, 0 ≤ y <N)
Find the smallest x that satisfies

  The partition of this subtree is [Nx × y, Nx × (y + 1) −1], and the partition width is Nx. The slot width is Nx-1.

(Calculation example)
FIG. 2 shows an example of “range of servant ID value” and shows “partition”, “partition width” and “slot” calculated from the range. Note that the maximum number N of downlinks is 10.

  3A and 3B show examples of partition calculation in the entire tree. Note that the maximum number N of downlinks is 10. In the figure, the numerical value in ◯ is the servant ID value.

(Servant participation)
The servant on the side connected to the logical network is called a connector, and the servant on the connection side is called a listener. A certain servant must accept a connection request from the down side even while performing the connection process to the up side. Therefore, the servant needs to be able to perform the process as a connector and the process as a listener in parallel.

(Connector processing)
The flow of connector processing will be described based on FIG. First, the contents of the servant ID list of the seed servant are substituted into the target servant ID list (S101).

  Next, the target servant ID is taken out one by one from the target servant ID list, and the following processing is executed (S103).

  Then, it connects to the target servant (S105).

  If the connection is not successful, the process returns to step S103, and if the connection is successful, the process proceeds to step S109 (S107).

  A participation request message with its own servant ID attached is transmitted to the listener (S109).

  A participation response message is received from the listener (S111).

  If the response classification of the participation response message is “OK”, the connector processing is terminated (S113).

  If the response classification of the participation response message is “connection instruction to another servant”, the connection instruction servant ID is extracted from the participation response message, and the process returns to step S105 as the target servant ID (S115).

(Listener processing)
Based on FIG. 5, the flow of listener processing will be described.

  First, a participation request message is received from the connector (S201).

  Next, the servant ID of the connector is extracted from the participation request message (S203).

  Then, the range of the servant ID value of the subtree is updated using the servant ID value of the connector (S205).

If the range of the servant ID value is [a, b] and the servant ID value of the connector is c, and if c <a, the range is updated to [c, b]
If b <c, the range is updated to [a, c]
When a ≦ c ≦ b, the range is not updated.

  For example, when the range of the servant ID value before receiving the participation request message is [1, 2] and the servant ID value extracted from the participation request message is “91”, the range of the updated servant ID value is [1, 91]. Further, when the range of the servant ID value before receiving the participation request message is [18, 19] and the servant ID value extracted from the participation request message is “10”, the range of the updated servant ID value is [10, 19].

  A partition and a slot are recalculated from the range of the servant ID value of the subtree (S207). At this time, due to partition expansion, a plurality of downlinks may correspond to the slot. At this time, the second and subsequent overflow downlinks are disconnected.

As described above, when the range of the servant ID value of the subtree is [vmin, vmax],
Nx × y ≤ vmin, vmax <Nx × (y + 1)
(x and y are integers x> 0, 0 ≤ y <N)
Find the smallest x that satisfies

  The partition of this subtree is [Nx × y, Nx × (y + 1) −1], and the partition width is Nx.

This sub-tree slot
[Nx × y, Nx × y + Nx-1-1],
[Nx × y + Nx-1, Nx × y + Nx-1 × 2-1],
:
[Nx × y + Nx-1 × (N-1), Nx × y + (Nx-1 × N)-1]
And the width of the slot is Nx-1.

  For example, when the range of the servant ID value before receiving the participation request message is [1, 2] and the partition is [0, 9], if the servant ID value extracted from the participation request message is “91”, the updated The servant ID value range is [1, 91], the recalculated partition is [0, 99], the slots are [0, 9], [10, 19], [20, 29], [30, 39]. , [40, 49], [50, 59], [60, 69], [70, 79], [80, 89], [90, 99].

  For example, when the range of the servant ID value before receiving the participation request message is [3, 7], the partition is [0, 9], and the servant ID value of the down servant is 3, 4, 7, it is extracted from the participation request message. If the servant ID value is “91”, the range of the updated servant ID value is [3, 91], the recalculated partition is [0, 99], and the slots are [0, 9], [10, 19]. ], [20, 29], [30, 39], [40, 49], [50, 59], [60, 69], [70, 79], [80, 89], [90, 99] Become.

  At this time, since there are down servants with servant ID values 3, 4, and 7 in the slot [0, 9], the link to the servant with servant ID values 4 and 7 is disconnected.

  A slot to which the servant ID value of the connector belongs is obtained (S209), and it is determined whether the slot is empty (S211). If the slot is empty, a participation response message having a response category of “OK” is transmitted. (S213), the process ends.

  If another servant is assigned to the slot, a response message of “connection instruction to other servant” and a participation response message in which the servant ID of the servant already assigned to the slot is set as the connection instruction servant are transmitted. (S215), and the process ends.

  Assuming that the state is already shown in FIG. 3A, steps S209 to S215 will be described based on FIG. When the servant ID value of the connector is “6”, the slot [0, 9] is obtained as the slot to which the servant ID value belongs (S209). Since another servant (servant ID value “5”) is already assigned to this slot, the response classification of “connection instruction to other servant” and the servant ID of the preceding servant (servant ID value “5”) Is sent as a connection instruction servant (S215).

  On the other hand, when the servant ID value of the connector is “21”, the slot [20, 29] is obtained as the slot to which the servant ID value belongs (S209). Since this slot is empty, a participation response message having a response category of “OK” is transmitted (S213).

(Servant detachment / link disconnection)
A physical network failure is detected by the servant as a link disconnection. In addition, the servant's detachment is also detected by the servant on the uplink side and the downlink side as a link disconnection. Processing when link disconnection is detected is shown below.

(Process when uplink is disconnected)
Based on FIG. 6, the process at the time of uplink disconnection is demonstrated.

  Hereinafter, for the sake of explanation, the servant ID of the servant having the servant ID value n is represented as IDn. For example, a servant ID of a servant with a servant ID value of 5 is denoted as ID5.

  First, a sibling servant ID list is extracted (S301). The sibling servant ID list means a servant ID list of sibling servants having the same up-servant. This list is sent from the up-servant at any time. In the example of FIG. 3A, “ID5”, “ID13”, and “ID90” are described in the sibling servant ID list of the servant with the servant ID value “5”. In the sibling servant ID list of the servant with the servant ID value “92”, “ID92”, “ID95”, and “ID99” are described.

  Next, the position of the own servant on the sibling servant ID list is obtained (S303).

  Then, it is checked whether the own servant is the first servant (S305).

  If the own servant is the first servant in the sibling servant ID list, connector processing is started (S307).

  If the own servant is not the first servant in the sibling servant ID list, the sibling servant ID list is substituted into the target servant ID list (S309), and connector processing is started (S311).

  Assuming that the state is already shown in FIG. 3A, steps S301 to S311 will be described based on FIG. First, a case where the servant with the servant ID value “90” is disconnected and the uplink of the servant with the servant ID value “92” is disconnected will be described. The servant with the servant ID value “92” extracts the sibling servant ID list (S301). The extracted list is described as “ID92, ID95, ID99”. Therefore, the servant with the servant ID value “92” is “first servant” on the sibling servant ID list (S303, 305). Therefore, the servant with the servant ID value “92” starts the connector processing with the seed servant with the servant ID value “3” as the target servant (S307).

  Next, a case where the servant with the servant ID value “90” is disconnected and the uplink of the servant with the servant ID value “95” is disconnected will be described. The servant with the servant ID value “95” extracts the sibling servant ID list (S301). The extracted list is described as “ID92, ID95, ID99”. Therefore, the position of the servant with the servant ID value “95” on the sibling servant ID list is “not the first servant” (S303, 305). Therefore, the servant with the servant ID value “95” substitutes the sibling servant ID list into the target servant ID list (S309), and starts connector processing for the servant with the servant ID value “92” (S307).

  FIG. 3B shows the state of the logical network in which these processes are completed. Note that the servant with the servant ID value “99” also performs the connector process for the servant with the servant ID value “92”, similarly to the servant with the servant ID value “95”.

  In this way, the logical network is configured autonomously even if the servant is disconnected or the link is disconnected. Therefore, costs such as management of configuration information become unnecessary. In addition, since the logical network is automatically reconstructed when a failure occurs, the fault tolerance is high.

(Process when downlink is disconnected)
When the downlink is disconnected, the slot to which the disconnected downlink is assigned is obtained, and the state of the slot is made empty.

(Logical network tree optimization)
In the present embodiment, in order to prevent the logical network tree from becoming redundant, tree optimization processing based on partitions is performed in parallel with the logical network configuration processing. The tree optimization process is performed in a shared manner between the seed servant at the top of the tree and other servants. Each process will be described below.

(Vertical seed servant tree optimization process)
1. The following processing is executed at regular intervals.

  1. Create a tree optimization message with the partition information of the local servant attached.

  1.2 Send a tree optimization message to all down-servants.

(Tree optimization processing for servants other than vertices)
Based on FIG. 7, the flow of the tree optimization process for servants other than the vertex will be described.

  It waits for a message from the upservant to be received (S401).

  It is determined whether the received message is a tree optimization message (S403).

  When branching to “YES” in step S403, the partition information of the upservant is extracted from the tree optimization message (S405).

  It is determined whether the self-servant partition is included in the up-servant partition (S407). If the self-servant partition is equal to the up-servant partition, it is determined as “not included”.

  When branching to “YES” in step S407, a tree optimization message to which the partition information of the own servant is attached is created (S409).

  A tree optimization message is transmitted to all down-servants (S411).

  When branching to “NO” in step S407, a reset message is transmitted to all down-servants (S413).

  All downlinks are disconnected (S415).

  All values, partitions, and slots of the subtree of the own servant are cleared (S417).

  When branching to “NO” in step S403, it is determined whether the received message is a reset message (S421).

  When branching to “YES” in step S421, connector processing is started.

  In addition, after receiving the reset message, the uplink is disconnected by the up-servant, but in order to prevent the connector processing from being activated twice, control is performed so that the processing at the time of uplink disconnection is not activated.

(Communication message routing)
Communication message routing will be described.

  A broadcast message that does not specify a destination is called a multicast message, and a message that specifies a destination servant ID is called a unicast message. The routing process of each communication message is shown below.

(Multicast message routing)
A multicast message routing process will be described with reference to FIG.

  First, a message is given to the application (S501).

  Next, it is determined whether an uplink exists (S503). If an uplink exists, a message is transmitted to the uplink (S505). Specifically, the port number and IP address of the upservant are notified to the TCP / IP software as the destination port number and the destination IP address, and the transmission is requested.

  Then, it is determined whether a downlink exists (S507), and if a downlink exists, a message is transmitted to each downlink (S509). Specifically, the TCP / IP software is notified of the port number and IP address of the down-servant as the destination port number and destination IP address, and requests transmission.

(Unicast message routing)
The unicast message routing process will be described with reference to FIG.

  First, it is determined whether the destination is itself (S601). Specifically, the destination servant ID included in the message header is compared with its own servant ID stored in its own storage device 103, and if both servant IDs match, it is determined that the destination is itself. .

  When branching to “YES” in step S601, a message is passed to the application (S603), and the process ends.

  When branching to “NO” in step S601, the servant ID value of the destination servant ID is obtained (S605).

  It is determined whether the calculated servant ID value is outside of its own partition (S607).

  When branching to “YES” in step S607, a message is transmitted to the uplink (S609).

  When branching to “NO” in step S607, a message is transmitted to the downlink of the corresponding slot (S611), and a message is transmitted to the uplink (S613).

  A “news distribution system” will be taken up as an application system of the present invention, and its mounting method and examples will be described. This news distribution system is a system for distributing news information in real time from a news transmission computer to a plurality of computers waiting to receive news.

  FIG. 10 shows a system configuration of the news distribution system.

  A communication network for constructing a logical network for a news distribution system using the method of the present invention and performing message communication on the logical network is referred to as a “PBTC communication library” (PBTC: Partition-Based Tree Construction). To tell.

  A program that broadcasts news information in response to an instruction from a news information sender is called a “news transmission program”. The news information is transmitted as a multicast message using the PBTC communication library.

  A program that waits for reception of news information from the PBTC communication library and displays the information on the computer screen at the time of reception is called a “news reception program”.

  Definition data used by the PBTC communication library is referred to as “network definition data”. Contains a servant ID list of seed servants necessary for the configuration of the logical network.

  As shown in FIG. 10, the servant 100 used in this embodiment has a storage device 103 connected to a main control unit (control means, hereinafter referred to as “CPU”) 101 that controls the whole. A transmission / reception unit 107 and a display device 109 are connected to the CPU 101 via an input / output control unit 105. Further, although not shown, a read only memory (ROM) in which a basic input / output system (BIOS) or the like is stored and a random access memory (RAM) having a program area and a data area are connected to the CPU 101.

  The storage device 103 is storage means such as a hard disk, a flexible disk, an optical disk, or a magneto-optical disk, and stores a news transmission program 111, a news reception program 113, a PBTC communication library 115, network definition data 117, and the like.

  FIG. 16A shows the contents of the network definition data 117. As shown in FIG. 16, the network definition data 117 includes a seed servant ID, a self-servant ID, a servant ID value range, partition information, slot information, and up / down servant information. Note that not all of the network definition data 117 need be stored in the storage device 103. For example, only the seed servant ID may be stored in the storage device 103, and the self-servant ID, the range of the servant ID value, and the like may be held on the RAM.

  Although not shown, the storage device 103 stores an operating system (OS) that can transmit and receive data according to a communication protocol such as TCP / IP.

  The servant 100a that performs only news transmission, the servant 100b that performs news reception and news transmission, and the servant 100c that performs only news reception transmit and receive news via the TCP / IP network 120. The servant 100a that performs only news transmission does not require the news reception program 113. The servant 100c that only receives news does not need the news transmission program 111.

  The display device 109 displays the news received by the news receiving program. The display device 109 includes a liquid crystal display such as a CRT (cathode ray tube) display and a TFT liquid crystal.

  The processing flow of each program module is shown below.

(PBTC communication library)
1. Wait for servant generation request.

2. When a servant generation request is received, the following thread is started.

-Connector thread-Listener thread-Link disconnection detection thread-Routing thread The routing thread waits for a message transmission / reception request from the host program.

(News transmission program)
1. A servant generation request is made to the PBTC communication library.

2. Wait for news distribution instructions from users.

3. When the news distribution instruction is received, the news information is requested to be transmitted to the PBTC communication library as a multicast message.

(News reception program)
1. A servant generation request is made to the PBTC communication library.

2. Request the PBTC communication library to receive a message.

3. Wait for the message to be received.

4). When the message is received, the news information is taken out and displayed on the screen of the display device 109.

5). Return to “3. Wait for message reception”.

  An embodiment of a news distribution system will be specifically described using a virtual case.

(Content of Example)
Company X uses a news distribution system to distribute company-wide news to employees. News is distributed from the department P specializing in news transmission to the receiving departments S1, S2,. The computer of each employee in the receiving department is set so that the news receiving program 113 is activated when activated.

  FIG. 11 shows a network configuration of a part related to the news distribution system. As shown in FIG. 11, the network address of the sending department P is 192.168.1.0/24, the network address of the receiving department S1 is 192.168.11.0/24, and the network address of the receiving department S2 is 192.168.12.0/24.

  In addition, the sending department P has two computers for confirming the news delivery, and the news receiving program is always activated. In the following, port numbers are omitted. The IP address of the news distribution confirmation computer is shown below.

192.168.1.1
192.168.1.2
Make these two computers act as seed servants for the logical network. Therefore, the contents of the network definition data are as follows.

SeedServant
192.168.1.1
192.168.1.2
The PBTC is adjusted as follows. The maximum number N of downlinks is “16”, and the IP address and port number of the servant ID are directly used as 6-byte integers as servant ID values.

FIG. 12 shows the department of the activated computer, the IP address, and the usage. As shown in FIG.
The computer with the IP address 192.168.1.1 to 192.168.1.2 of the sending department P is a news receiving computer and seed servant,
The computers with IP addresses 192.168.1.3 to 192.168.1.4 of the sending department P are news sending computers,
The computers with IP addresses 192.168.11.1 to 192.168.11.4 of the receiving department S1 are news receiving computers,
The computers having the IP addresses 192.168.12.1 to 192.168.12.3 of the receiving department S2 are also news receiving computers.

FIG. 13 shows the configuration of the logical network of the computer shown in FIG. As shown in FIG.
The vertex servant is the servant of the computer with IP address 192.168.1.1
The down servant of the computer with the IP address 192.168.1.1 is the servant of the computer with the IP addresses 192.168.1.2, 192.168.11.4, 192.168.12.2
The down servant of the computer with IP address 192.168.1.2 is the servant of the computer with IP addresses 192.168.1.3 and 192.168.1.4,
The down servant of the computer with the IP address 192.168.11.4 is the servant of the computer with the IP address 192.168.11.1 to 192.168.11.3,
The down servant of the computer with the IP address 192.168.12.2 is the servant of the computer with the IP address 192.168.12.1, 192.168.12.3.

  The operation of the news distribution system will be described by taking the following scenarios 1 and 2 as examples. In the following, it is assumed that the logical network in FIG. 13 is configured.

(Scenario 1: Start of news receiving computer [192.168.12.4])
The flow of operations from when the news receiving computer [192.168.12.4] belonging to the news receiving department S2 starts up to join the logical network is shown below.

1. The news reception program starts and servant [192.168.12.4] is generated.

2. The servant [192.168.12.4] sets [192.168.1.1] and [192.168.1.2] to the target servant list (S101), and extracts the servant ID of the servant [192.168.1.1], which is the first seed servant (S103). Then, it connects to the servant [192.168.1.1] (S105), and transmits a participation request attached with its own servant ID [192.168.12.4] (S109).

3. The servant [192.168.1.1] receives the participation request from the servant [192.168.12.4] (S201), extracts the servant ID of the servant [192.168.12.4] from the participation request (S203), and then extracts the servant of the servant [192.168.12.4] The subtree is updated using the ID value (S205), the partition and the slot are recalculated from the range of the subtree (S207), and the slot to which the servant ID value of the servant [192.168.12.4] belongs is obtained (S209). It is determined whether the assigned slot is empty (S211), and a connection instruction to the servant [192.168.12.2] assigned to the obtained slot is returned as a participation response (S215).

As a result, the servant ID value range of the servant [192.168.1.1] is
[192.168.1.1, 192.168.12.3]
From
[192.168.1.1, 192.168.12.4]
Is updated.

The partition of the servant [192.168.1.1]
[192.168.0.0, 192.168.15.255]
Remains.

  Then, based on the slot information shown in FIG. 16B, the slot [192.168.12.0, 192.168.12.255] to which the servant [192.168.12.4] belongs is obtained (S209). As shown in FIG. 16B, the servant [192.168.12.2] already exists in the slot [192.168.12.0, 192.168.12.255]. Therefore, it is determined that the obtained slot is not empty (S211), and a connection instruction to [192.168.12.2] is returned as a participation response (S215).

  The servant [192.168.12.4] receives the participation response from the servant [192.168.1.1] (S111).

  Since the content of the participation response is not “OK”, the servant ID of the servant [192.168.12.2] is extracted from the participation response, this servant ID is set as the new target servant ID (S115), and the servant [192.168.12.2] is connected. (S105), a participation request is transmitted (S109).

  The servant [192.168.12.2] receives the participation request from the servant [192.168.12.4] (S201), extracts the servant ID of the servant [192.168.12.4] from the participation request (S203), and then extracts the servant of the servant [192.168.12.4] The subtree is updated using the ID value (S205), the partition and the slot are recalculated from the range of the subtree (S207), and the slot to which the servant ID value of the servant [192.168.12.4] belongs is obtained (S209). It is determined whether the given slot is empty (S211).

Specifically, the servant ID value range for servant [192.168.12.2] is
[192.168.12.1, 192.168.12.3]
From
[192.168.12.1, 192.168.12.4]
Is updated.

The partition of the servant [192.168.12.2]
[192.168.12.0, 192.168.12.15]
Remains.

  Since the slot to which the servant [192.168.12.4] belongs is empty, the servant [192.168.12.2] returns a connection OK participation response (S213). As a result, the servant [192.168.12.4] becomes a down servant of the servant [192.168.12.2].

  FIG. 14 shows a logical network in which the servant [192.168.12.4] is a down servant of the servant [192.168.12.2].

  Thus, the logical network is autonomously configured in accordance with the participation of the servant. Therefore, the cost of managing the configuration information of the entire logical network is unnecessary.

(Scenario 2: News transmission from news transmission computer [192.168.1.4])
The flow of operations when news is sent from the news sending computer [192.168.1.4] (after joining the logical network) belonging to the news sending department P is shown below.

  The news transmission program uses the servant [192.168.1.4] to send the news as a multicast message.

  The servant [192.168.1.4] checks whether an uplink exists based on the up / down servant information (FIG. 16C) stored in its own storage device 103 (S503). Then, the news is transmitted to the up-servant [192.168.1.2] as a multicast message (S505), and it is further checked whether there is a downlink (S507). Since there is no downlink, the process is terminated.

  The servant [192.168.1.2] passes the news to the news receiving program (S501), and whether there is an uplink based on the up / down servant information (FIG. 16 (d)) stored in the local storage device 103. Check (S503), since there is an uplink, send news as a multicast message to the up-servant [192.168.1.1] (S505), further check whether there is a downlink (S507), and because there is a downlink, News is transmitted to the down servant [192.168.1.3] (S509).

  Note that the servant [192.168.1.4] also corresponds to the down servant, but the servant [192.168.1.4] is the source of the news received by the servant [192.168.1.2], so there is no need to transmit the news. For this reason, the servant [192.168.1.4] is excluded from the transmission destination. In other words, the servant [192.168.1.2] that has received the news acquires the servant ID as the transmission destination candidate from the up / down servant information (FIG. 16D). Send news to the remaining servants except for one servant [192.168.1.4].

  The servant [192.168.1.1] passes the news to the news receiving program (S501), and whether there is an uplink based on the up / down servant information (FIG. 16 (e)) stored in the local storage device 103. Check (S503), since there is no uplink, the process proceeds to step S507 to check whether there is a downlink (S507). Since there is a downlink, the servant [192.168.11.4] and the servant [192.168.12.2] that are the down servants. ] Is transmitted to] (S509).

  The servant [192.168.1.2] also corresponds to the down servant, but the servant [192.168.1.2] is the source of the news received by the servant [192.168.1.1], and therefore it is not necessary to transmit the news. For this reason, the servant [192.168.1.2] is excluded from the transmission destination. In other words, the servant [192.168.1.1] that has received the news acquires the servant ID as the transmission destination candidate from the up / down servant information (FIG. 16E). Send news to the remaining servants except for one servant [192.168.1.2].

  The servant [192.168.11.4] passes the news to the news receiving program (S501), and whether there is an uplink based on the up / down servant information (FIG. 16 (f)) stored in the local storage device 103. In step S503, an uplink exists, but since the up-servant [192.168.1.1] is a message transmission source, the process proceeds to step S507 without transmitting a message to the up-servant [192.168.1.1].

  Then, it is checked whether a downlink exists (S507), and news is transmitted to the servants [192.168.11.1], [192.168.11.2], and [192.168.11.3] that are the down servants (S509).

  Similarly to the servant [192.168.11.4], the servant [192.168.12.2] also transmits news to the servants [192.168.12.1], [192.168.12.3], and the servant [192.168.12.4] corresponding to the down servant (S509). ).

FIG. 15 shows a multicast message transfer status. As shown in FIG.
From servant [192.168.1.4] to servant [192.168.1.2]
From servant [192.168.1.2] to servant [192.168.1.1], [192.168.1.3]
From servant [192.168.1.1] to servant [192.168.11.4], [192.168.12.2]
From servant [192.168.11.4] to servant [192.168.11.1], [192.168.11.2], [192.168.11.3]
From servant [192.168.12.2] to servant [192.168.12.1], [192.168.12.3], [192.168.12.4]
Multicast messages are transferred sequentially.

  Each news receiving program that has received the multicast message displays the news on the screen.

  In this way, even for network devices that do not support IP multicast communication, multicast can be performed without incurring costs for setting and maintenance, and without depending on a physical network configuration such as a subnet unit. It becomes possible.

(A) is a figure for demonstrating a servant and a seed servant, (b) is a figure for demonstrating an up servant, a down servant, an uplink, and a downlink. It is a figure for demonstrating the range of a servant ID value, a partition, the width of a partition, and a slot. (A) illustrates a logical network configuration and corresponding servant ID values, partitions, and slots, and (b) illustrates a case where some servants leave and links are disconnected. It is a flowchart for demonstrating the flow of a connector process. It is a flowchart for demonstrating the flow of a listener process. It is a flowchart for demonstrating the flow of the process at the time of uplink disconnection. It is a flowchart for demonstrating the flow of a tree optimization process. It is a flowchart for demonstrating the flow of the routing process of a multicast message. It is a flowchart for demonstrating the flow of the routing process of a unicast message. It is a figure which shows the system configuration | structure of a news delivery system. It is a figure which shows the structure of the network of the part in connection with a news delivery system. It is a figure which shows the department of the computer which has started, an IP address, and a use. It is a figure which shows the structure of the logical network of the computer shown in FIG. FIG. 14 is a diagram illustrating a logical network in which a servant [192.168.12.4] participates in the logical network illustrated in FIG. 13 and becomes a servant [192.168.12.2] down-servant. It is a figure which shows the transfer condition of the multicast message in the logical network shown in FIG. (A) explains network definition data, (b) explains slot information, and (c) to (f) are diagrams for explaining up / down servant information.

Explanation of symbols

101 ... Main control unit (CPU)
DESCRIPTION OF SYMBOLS 103 ... Memory | storage device 105 ... Input / output control part 107 ... Transmission / reception part 109 ... Display apparatus 111 ... News transmission program 113 ... News reception program 115 ... PBTC communication library 117 ... Network definition data

Claims (3)

A unicast message transmission method for transmitting a unicast message on a logical network, comprising:
The servant that received the message
Storing the own servant ID, the partition, each slot included in the partition, the up servant, and the down servant if there is a down servant belonging to each slot;
Reading a destination servant ID from the received message;
Comparing the destination servant ID with the self-servant ID;
Passing the message to a higher-level application if the destination servant ID and the self-servant ID match;
When the destination servant ID and the self-servant ID do not match, the servant ID value obtained by mapping the destination servant ID to a unique integer value is compared with the partition,
If the servant ID value is outside the partition, send the message to the upservant;
If the servant ID value is in the partition, in addition to sending the message to the up-servant, the servant ID value is compared with each slot, and the slot of the slot to which the servant ID value belongs Sending the message to a down servant;
Unicast message transmission method comprising: A unicast message transmission program executed by a computer that transmits a unicast message on a logical network,
To the computer that received the message,
Storing the own servant ID, the partition, each slot included in the partition, the up servant, and the down servant if there is a down servant belonging to each slot;
Reading a destination servant ID from the received message;
Comparing the destination servant ID with the own servant ID;
Passing the message to a higher-level application when the destination servant ID and the own servant ID match;
When the destination servant ID and the own servant ID do not match, the servant ID value obtained by mapping the destination servant ID to a unique integer value is compared with the partition;
If the servant ID value is outside the partition, send the message to the upservant;
If the servant ID value is in the partition, in addition to sending the message to the up-servant, the servant ID value is compared with each slot, and the slot of the slot to which the servant ID value belongs. Sending the message to a down servant;
Unicast message sending program to execute A unicast message transmitting apparatus for transmitting a unicast message on a logical network,
Receiving means for receiving the message;
Storage means for storing the own servant ID, the partition, each slot included in the partition, the up servant, and the down servant if there is a down servant belonging to each slot;
Reading means for reading a destination servant ID from the received message;
Destination servant ID / own servant ID comparing means for comparing the destination servant ID and the own servant ID;
Means for passing the message to a higher-level application when the destination servant ID matches the own servant ID;
A servant ID value / partition comparison unit that compares the partition with a servant ID value obtained by mapping the destination servant ID to a unique integer value when the destination servant ID and the self-servant ID do not match;
If the servant ID value is outside the partition, a transmission means for up-servant that transmits the message to the up-servant;
If the servant ID value is in the partition, in addition to sending the message to the up-servant, the servant ID value is compared with each slot, and the slot of the slot to which the servant ID value belongs A transmission means for down-servant that transmits the message to the down-servant;
A unicast message transmission apparatus having: