JP5304700B2 - Status notification method and communication system - Google Patents

Description

  The present invention relates to a state notification method and a communication system for notifying a terminal of the state of another terminal in a communication system including a plurality of terminals connected via a network.

  2. Description of the Related Art Conventionally, in a communication system including a plurality of terminals connected via a network, a function (so-called “presence function”) for notifying a terminal of the status of another terminal is used. The communication system includes at least a plurality of terminals and a presence server. The presence server manages presence information indicating the state of each terminal. For example, when monitoring the status of another terminal A, the terminal B requests the presence server to register that the status of the terminal A is notified to the terminal B. When the state of the terminal A is notified from the terminal A, the presence server transmits a message for notifying the state of the terminal A to the terminal B registered as the notification destination of the state of the terminal A.

  When the presence server notifies a plurality of terminals of the state of a certain terminal, the presence server has to perform a plurality of processes for notifying each terminal of the state in parallel. In order to distribute the load applied to the presence server, for example, in Patent Document 1, a database server that stores presence information and a plurality of presence servers that notify the terminal that the presence information has been changed to another terminal. A communication system for notifying the state is disclosed.

JP 2006-244100 A

  In the communication system disclosed in Patent Document 1, a database server that stores presence information must transmit a message to each of the presence servers. Therefore, when the number of presence servers increases as the number of terminals increases, the load on the database server increases. In other words, the communication system disclosed in Patent Document 1 cannot fundamentally reduce the load on the database server that increases as the number of terminals increases.

  An object of the present invention is to provide a state notification method and a communication system capable of reducing a load applied to a database server in a communication system that notifies a terminal of the state of another terminal.

  The status notification method according to the first aspect of the present invention includes a plurality of terminals, a database server capable of managing presence information indicating the status of each of the plurality of terminals, and at least one of the plurality of terminals. A status notification method performed in a communication system including a plurality of relay servers that relay messages to and from the database server, wherein the database server is a notification destination of the status of each of the plurality of terminals A registration step for registering information for identifying the notification destination terminal in the storage means, and the notification source terminal via a relay server to which the notification source terminal that is one of the plurality of terminals is connected Status notification step of transmitting the presence information of the notification source terminal to the database server, and the presence information of the notification source terminal transmitted in the status notification step The database server that has received the ID specifies first notification destination information for specifying the notification destination terminal and a relay server connected to the notification destination terminal based on the information registered in the registration step A first transmission step of transmitting one piece of information including relay information to one of the plurality of relay servers, and the relay server that has received the one piece of information transmitted in the first transmission step, An output step of outputting second notification destination information specifying the notification destination terminal specified by the first notification destination information and presence information of the notification source terminal to the relay server specified by the relay information; and the output step Presence that the relay server that has input the information output in step 2 is input to the terminal identified by the second notification destination information among the terminals connected to the relay server. And a second transmission step of transmitting the broadcast.

  According to the state notification method according to the first aspect, the database server simply sends one piece of information including information for specifying the notification destination terminal to any one of the plurality of relay servers. The status of the terminal can be notified to the notification destination terminal. Even when the number of notification destination terminals is large, the database server does not need to repeat transmission / reception of information with a plurality of relay servers. Therefore, the communication system can notify the notification destination terminal of the state of the notification source terminal without increasing the load on the database server.

  In the output step, when the plurality of notification destination terminals are specified by the first notification destination information and two or more of the plurality of notification destination terminals are connected to one relay server in the output step, One second notification destination information specifying two or more notification destination terminals may be output to the relay server. In addition to reducing the load on the database server, the communication system can also reduce the number of times information is transmitted and received between a plurality of relay servers. Therefore, the communication system can further reduce the load on the entire system.

  In the first transmission step, the database server sends the first information including the first notification destination information and the relay information to a relay server that relays the presence information together with a response to the presence information being received. You may send it. The communication system can further reduce the number of times the database server transmits information. As a result, the load on the database server is reduced.

  The status notification method further includes a first acquisition step in which a relay server that relays presence information of the notification source terminal in the status notification step acquires the presence information to be relayed when relaying the presence information. Also good. In the output step, the relay server may output the presence information acquired in the first acquisition step. The database server does not need to include the presence information of the notification source terminal in the one information transmitted to the relay server. Therefore, the communication system can reduce the amount of data transmitted and received.

  In the status notification method, the database server that has received the presence information of the notification source terminal transmitted in the status notification step acquires processing information that is information related to processing executed by each of the plurality of relay servers. The second acquisition step, and the database server that has acquired the processing information in the second acquisition step transmits the one information including the notification destination information and the relay information based on the acquired processing information And a selection step of selecting a previous relay server from the plurality of relay servers. In the first transmission step, the database server may transmit the one information to the relay server selected in the selection step. The database server can select a relay server that transmits information in accordance with information on processing executed by each relay server. Therefore, the communication system can prevent the processing load from being biased to a part of the system.

  In the first transmission step, the database server may transmit presence information of the notification source terminal included in the one information. In the output step, the relay server may output the presence information included in the received one information. By including the presence information of the notification source terminal in one piece of information transmitted from the database server to the relay server, the communication system can reliably notify the notification destination terminal of the presence information of the notification source terminal.

  The status notification method may further include a storage control step in which each of the relay servers and the database server stores a common identifier between each of the relay servers and the database server in a storage unit. In the first transmission step, the database server may include the identifier information related to an identifier common to the relay server specified by the relay information, and transmit the identifier information. In the output step, the relay server that has received the one information transmitted in the first transmission step outputs the identifier information included in the one information together with the second notification destination information and the presence information. That's fine. In the second transmission step, if the relay server that has input the information output in the output step has a common identifier with the database server, the input presence information May be transmitted to the notification destination terminal. The relay server that transmits the presence information to the notification destination terminal uses the identifier to indicate that the input second notification destination information and presence information are reliable information output from the database server via another relay server. Judgment can be made. Therefore, the communication system can smoothly transmit and receive accurate information.

  Each of the plurality of terminals may operate as a SIP client that communicates with other terminals in accordance with SIP (Session Initiation Protocol). The relay server may operate as a SIP proxy server that establishes a SIP session between the plurality of terminals. The communication system can smoothly communicate according to general-purpose SIP. The communication system can easily realize the presence function using a general-purpose SIP message. The presence function can be easily realized without significantly changing the configuration of an existing communication system that performs communication according to SIP. The relay server can execute both establishment of communication between a plurality of terminals and control of the presence function. Therefore, the communication system does not need to include a server for establishing communication and a server for controlling the presence function.

  A communication system according to a second aspect of the present invention includes a plurality of terminals, a database server capable of managing presence information indicating a state of each of the plurality of terminals, at least one of the plurality of terminals, and the A communication system including a plurality of relay servers that relay messages to and from a database server, wherein the database server identifies one or more notification destination terminals that are notification destinations of the states of the plurality of terminals The presence of the notification source terminal via a relay server connected to the notification source terminal in a registration unit that registers information to be stored in a storage unit and a notification source terminal that is one of the plurality of terminals Status notification means for transmitting information to the database server; and before the database server transmits the information by the status notification means. When receiving presence information of a notification source terminal, based on information registered by the registration means, first notification destination information for specifying the notification destination terminal, and a relay connected to the notification destination terminal One piece of information including relay information for specifying a server is transmitted to one of the plurality of relay servers, and is transmitted by the first transmission unit in each of the plurality of relay servers. The second notification destination information for specifying the notification destination terminal specified by the first notification destination information to the relay server specified by the relay information, and the notification source terminal In each of the output means for outputting presence information and the information output by the output means in each of the plurality of relay servers, the terminal connected to itself is connected. , The terminal identified by the second notification destination information, and a second transmission means for transmitting presence information input.

  According to the communication system according to the second aspect, the database server simply transmits one piece of information including information for specifying the notification destination terminal to any one of the plurality of relay servers. Can be notified to the notification destination terminal. Even when the number of notification destination terminals is large, the database server does not need to repeat transmission / reception of information with a plurality of relay servers. Therefore, the communication system can notify the notification destination terminal of the state of the notification source terminal without increasing the load on the database server.

1 is a diagram showing a system configuration of a communication system 100. FIG. 2 is a block diagram showing an electrical configuration of the database server 1. FIG. 3 is a block diagram showing an electrical configuration of a relay server 2. FIG. 3 is a block diagram showing an electrical configuration of a terminal 3. FIG. 3 is a sequence diagram showing an example of processing executed by the communication system 100. FIG. It is a sequence diagram which shows an example of the process which the communication system 100 performs when multiple notification destination terminals are registered. It is a figure which shows an example of the response message which the database server 1 replies with respect to a status notification. It is a flowchart of the relay server selection process which the database server 1 which concerns on 2nd embodiment performs.

  Hereinafter, a communication system 100 according to a first embodiment that embodies the present invention will be described with reference to the drawings. The drawings to be referred to are used for explaining technical features that can be adopted by the present invention. The configuration of the apparatus, the flowcharts of various processes, and the like described in the drawings are not intended to be limited to these, but are merely illustrative examples.

  An overview of the communication system 100 will be described with reference to FIG. The communication system 100 includes a database server 1, a plurality of relay servers 2, and a plurality of terminals 3. The terminal 3 included in the communication system 100 transmits / receives data such as audio data and image data to / from other terminals 3 via the network 8 (see FIGS. 2 to 4) by P2P (peer to peer). Can do. A plurality of users who use each terminal 3 can perform a remote conference using data transmitted and received even when they are not at the same site. That is, the communication system 100 of the present embodiment is a video conference system used for conducting a video conference. However, the present invention can be applied to communication systems other than the video conference system. For example, the present invention can be applied to a communication system that transmits / receives character data to perform so-called “chat”, a communication system that transmits / receives voice data to perform a telephone call, and the like.

  In the communication system 100, SIP (RFC3261) is used as a bidirectional protocol for a plurality of terminals 3 to start communication on the network 8. SIP (Session Initiation Protocol) is a protocol for establishing an end-to-end session on the network 8 and can easily realize real-time communication. Each of the terminals 3 operates as an SIP client that communicates with other terminals 3 according to SIP. Each of the relay servers 2 is a SIP proxy server that establishes a session between a plurality of terminals 3 according to SIP. Since a method for establishing a session by SIP is known, a detailed description thereof will be omitted.

  The communication system 100 has a function (so-called “presence function”) for notifying the terminal 3 of the state of the other terminal 3. By using the presence function, the user can know the state of another user without establishing communication between the terminal 3 used by the user and the terminal 3 used by another user.

  In general, a server is not suitable for a process of transmitting information and receiving a response, compared to a process of receiving information and transmitting a response. Specifically, when the server transmits a message including presence information to another device, the server needs to wait for a message response. When there is no message response, the server also needs to perform processing such as message retransmission. In particular, when the server notifies the state of a certain terminal to a large number of terminals, processing for the large number of terminals must be executed at the same time, so that an excessive load is instantaneously applied to the server. When processing performed on the server is delayed, execution of the presence function is stagnant.

  The communication system 100 of this embodiment includes a database server 1 and a plurality of relay servers 2 as servers for executing the presence function. The database server 1 is connected to each of the plurality of relay servers 2. Each relay server 2 can be connected to one or a plurality of terminals 3 and can also transmit and receive messages between the relay servers 2. The communication system 100 distributes processing for executing the presence function to the database server 1 and the relay server 2 and performs characteristic processing in transmission / reception of messages between the servers, so that the entire system, particularly the database server 1 is applied. The load can be reduced. Details of processing executed by the communication system 100 will be described later.

  The electrical configuration of the database server 1 will be described with reference to FIG. The database server 1 is a server that stores and manages presence information of each terminal 3. The database server 1 includes a CPU 10 that controls the database server 1. Connected to the CPU 10 are a ROM 11, a RAM 12, a hard disk drive (hereinafter referred to as “HDD”) 13, and an external communication I / F 14. The ROM 11 stores a program for operating the database server 1, an initial value, and the like. The RAM 12 temporarily stores various information used in the control program. The HDD 13 is a non-volatile storage device that stores various types of information. The external communication I / F 14 connects the database server 1 to the network 8.

  The HDD 13 is provided with various storage areas such as a presence information storage area 131, a terminal registration information storage area 132, and an identifier storage area 133. The presence information storage area 131 mainly stores presence information. As described above, the presence information is information indicating the state of each terminal 3, and the presence information is stored in association with each terminal 3. The terminal registration information storage area 132 stores information on the terminal 3 that is the notification destination of each state of the terminal 3 (hereinafter referred to as “notification destination terminal”). Specifically, the terminal registration information storage area 132 may be referred to as notification destination information for specifying a notification destination terminal and a relay server 2 connected to the notification destination terminal (hereinafter referred to as “connection server”). ) Is stored in association with each of the terminals 3 (hereinafter referred to as “notification source terminals”) that are notified of the status of other terminals. The identifier storage area 133 stores identifiers that are held in common with the relay server 2. The identifier is included in the message transmitted to the relay server 2 together with the notification destination information. Although details will be described later, the relay server 2 determines whether or not the message received from the other relay server 2 is a reliable message using the identifier.

  The electrical configuration of the relay server 2 will be described with reference to FIG. The relay server 2 relays transmission / reception of presence information between the database server 1 and the terminal 3. Furthermore, as described above, the relay server 2 operates as a SIP proxy server that establishes a session between a plurality of terminals 3 in accordance with SIP. The relay server 2 includes a CPU 20 that controls the relay server 2. A ROM 21, a RAM 22, an HDD 23, and an external communication I / F 24 are connected to the CPU 20. The HDD 23 is provided with a presence information storage area 231 and an identifier storage area 232. The relay server 2 can store presence information relayed between the terminal 3 and the database server 1 in the presence information storage area 231. The identifier storage area 232 stores identifiers that are held in common with the database server 1. In this embodiment, the database server 1 and the relay server 2 give an identifier to each of the notification destination terminals. Therefore, the relay server 2 can reliably determine the reliability of the message using the identifier. However, the database server 1 and the relay server 2 may give an identifier to each of the relay servers 2.

  The electrical configuration of the terminal 3 will be described with reference to FIG. The terminal 3 is a personal computer capable of performing various kinds of information processing, a dedicated terminal used for a video conference, or the like. The terminal 3 includes a CPU 30 that controls the terminal 3. A ROM 31, a RAM 32, an HDD 33, an external communication I / F 34, a microphone 35, a speaker 36, a camera 37, a display device 38, and an operation unit 39 are connected to the CPU 30. The microphone 35 inputs the voice of the base where the terminal 3 is arranged. The speaker 32 outputs sound. The camera 37 captures an image of the base where the terminal 3 is arranged. The display device 38 displays an image. The operation unit 39 is operated for the user to input various instructions to the terminal 3.

  With reference to FIG. 5, the flow of processing performed in the communication system 100 will be described. Processing described below is performed by the CPU 10 of the database server 1, the CPU 20 of the relay server 2, and the CPU 30 of the terminal 3.

  In the example illustrated in FIG. 5, a notification source terminal that notifies its own state to another terminal 3 among a plurality of terminals 3 is a terminal 3 </ b> A. A notification destination terminal that monitors the state of the terminal 3A is assumed to be a terminal 3B. Among the plurality of relay servers 2, the relay server 2 connected to the terminal 3A (the connection server of the terminal 3A) is referred to as a relay server 2A, and the connection server of the terminal 3B is referred to as a relay server 2B. FIG. 5 illustrates a case where the notification destination terminal is only one of the terminals 3B in order to facilitate understanding of the processing flow. A case where a plurality of notification destination terminals are registered will be described later with reference to FIG. The terminal 3A and the terminal 3B transmit the SIP message of the registration request “REGISTER” to the relay server 2 to be connected before performing the following processing, and the relay server serves as one of the terminals 3 that performs communication within the communication system 100. 2 is registered.

  The terminal 3A, which is the notification source terminal, transmits a SIP message of status notification “PUBLISH” to the connected relay server 2A (S1). The terminal 3A transmits “PUBLISH” to the relay server 2A when the state of the terminal 3A changes and when a predetermined time has elapsed since the previous “PUBLISH” transmission. The terminal 3A includes presence information indicating the state of the terminal 3A in the SIP message “PUBLISH”. For example, the terminal 3A includes “open” when the user is present, and “closed” when the user is away from the message as presence information indicating the state of the terminal 3A. When the relay server 2A receives “PUBLISH” from the terminal 3A, it acquires the presence information contained in the received message and stores it in the presence information storage area 231 (see FIG. 3) (S2). The relay server 2A transfers the received status notification to the database server 1 (S3). The database server 1 stores the presence information included in the received status notification in the presence information storage area 131 (see FIG. 2) in association with the terminal 3A (S4).

  At the time when the database server 1 executes S4, the notification destination terminal that monitors the state of the terminal 3A is not yet registered. Therefore, the database server 1 returns only the response to the status notification to the relay server 2A without transmitting the presence information of the terminal 3A (S5). The relay server 2A returns a response to “PUBLISH” to the terminal 3A (S6). Through the above processing (S1 to S6), the database server 1 stores the presence information of the terminal 3A.

  Next, the terminal 3B transmits a SIP message of the status acquisition registration request “SUBSCRIBE” to the connected relay server 2B (S7). “SUBSCRIBE” is a message transmitted to request the database server 1 to register that the database server 1 notifies itself of the state of the terminal 3A. The relay server 2B transfers the received status acquisition registration request to the database server 1 (S8). The database server 1 registers notification destination information indicating that the notification destination of the state of the terminal 3A is the terminal 3B in the terminal registration information storage area 132 (see FIG. 2). The database server 1 registers, in the terminal registration information storage area 132, relay information indicating that the relay server 2 connected to the terminal 3B (connection server of the terminal 3B) is the relay server 2B (S9).

  The database server 1 generates an identifier b corresponding to the terminal 3B and stores it in the identifier storage area 133 (S10). As described above, in this embodiment, an identifier corresponding to each of the terminals 3 is generated separately, but an identifier may be generated in association with each of the relay servers 2. The database server 1 includes the presence information of the terminal 3A and the generated identifier b in the response message to the status acquisition registration request, and transmits it to the relay server 2B (S11). The relay server 2B stores the identifier b included in the received message in the identifier storage area 232 as the identifier of the terminal 3B (S12). As a result, the identifier b is shared between the database server 1 and the relay server 2B.

  The relay server 2B returns a response to “SUBSCRIBE” to the terminal 3B (S13). The relay server 2B includes the presence information of the terminal 3A in the SIP message “NOTIFY” for notifying the state of the terminal 3A, and transmits it to the terminal 3B (S14). The terminal 3B returns a response to “NOTIFY” to the relay server 2B (S15). Through the above processing (S7 to S15), the terminal 3B is registered in the database server 1 as the notification destination of the state of the terminal 3A, and the state of the terminal 3A currently managed by the database server 1 is notified to the terminal 3B. Is done.

  When the state of the terminal 3A changes or when a predetermined time has elapsed since the last transmission of “PUBLISH”, the terminal 3A that is the notification source terminal transmits the SIP message of the state notification “PUBLISH” to the relay server 2A again. (S16). The relay server 2A acquires presence information included in the received message (S17), and transfers a status notification to the database server 1 (S18). The database server 1 stores the presence information of the terminal 3A (S19).

  At the time when the database server 1 executes S19, the terminal 3B is registered as a notification destination of the state of the terminal 3A. In this case, the database server 1 transmits to the relay server 2A, including the notification destination information, the relay information, and the identifier in one response message for the status notification (S20). The notification destination information in S20 is information for specifying that the notification destination terminal is the terminal 3B. The relay information is information for specifying that the relay server 2B is connected to the terminal 3B. The identifier is an identifier b corresponding to the terminal 3B that is shared by the database server 1 and the relay server 2B. The database server 1 of this embodiment includes the identifier directly in the response message. However, the communication system 100 may encrypt the identifier and include it in the response message using a public key encryption method, a challenge response method, or the like. The same applies to the messages transmitted in S11 described above and S22 described later.

  The relay server 2A returns a response to “PUBLISH” to the terminal 3A (S21). The relay server 2A specifies from the information included in the received message that the notification destination terminal is the terminal 3B and that the connection server of the terminal 3B is the relay server 2B. The relay server 2A adds the presence information of the terminal 3A acquired in S17 to the SIP message of the status notification “NOTIFY” for notifying the presence information of the terminal 3A, and the notification destination information indicating that the notification destination terminal is the terminal 3B. And the identifier b are transmitted to the relay server 2B (S22). When relaying the presence information transmitted from the terminal 3A to the database server 1, the relay server 2A acquires the presence information of the terminal 3A (S17), and can include the acquired presence information in “NOTIFY” (S22). ). Therefore, the database server 1 does not need to include the presence information of the terminal 3A in the message transmitted in S20. As a result, the database server 1 can reduce the data amount of the message transmitted in S20. However, the database server 1 can also include the presence information of the terminal 3A in the message transmitted in S20. The relay server 2A may include presence information included in the message received from the database server 1 in “NOTIFY” (S22).

  The relay server 2B determines whether the identifier included in the received message matches the identifier b stored in association with the terminal 3B, and confirms the identifier (S23). In the example shown in FIG. 5, the identifier received by the relay server 2B matches the identifier stored in advance by the relay server 2B. Therefore, the relay server 2B determines that the message received from the relay server 2A is a reliable message including information transmitted from the database server 1. The relay server 2B returns a response to “NOTIFY” to the relay server 2A (S24). The relay server 2B transmits a status notification “NOTIFY” including the presence information of the terminal 3A to the terminal 3B that is the specified notification destination terminal (S25). The terminal 3B returns a response to “NOTIFY” to the relay server 2B (S26). Although not shown, when the identifiers do not match, the relay server 2B does not transmit “NOTIFY” to the terminal 3B. Through the above processing (S20 to S26), the state of the terminal 3A notified to the database server 1 in S16 to S18 is notified from the database server 1 to the notification destination terminal (terminal 3B).

  Next, with reference to FIG. 6 and FIG. 7, the flow of processing when a plurality of terminals 3 are monitoring the state of one terminal 3 will be described. The example shown in FIGS. 6 and 7 is a modification of the example shown in FIG. In the example shown in FIGS. 6 and 7, as the terminal 3 (notification destination terminal of the terminal 3A) that monitors the state of the terminal 3A (see FIG. 5) that is the notification source terminal, the terminal B1, the terminal B2, the terminal B3, and the terminal C1 is registered in the database server 1. Terminals B1 to B3 are connected to the relay server 2B. The terminal C1 is connected to the relay server 2C. FIG. 6 shows the processing after the presence information of the terminal 3A as the notification source terminal is transmitted to the database server 1 via the relay server 2A in the above state.

  When the database server 1 receives and registers the presence information of the terminal 3A, it returns a response message to the relay server 2A (S31). When there are a plurality of notification destinations of the state of the terminal 3A, the database server 1 includes all of the notification destination information, relay information, and identifier for each of the plurality of notification destination terminals in one response message.

  FIG. 7 shows an example of the response message transmitted in S31 of FIG. Messages sent and received between the database server 1 and the relay server 2 do not need to comply with SIP. The communication system 100 according to the present embodiment conforms to SOAP (Simple Object Access Protocol) which is one of protocols independent of language and platform. Various information can be included in the response message. For example, a character string 51 shown in FIG. 7 indicates an expiration date (second) in which the database server 1 holds the presence information of the terminal 3A.

  A character string 52 illustrated in FIG. 7 is a character string including notification destination information and relay information. Specifically, the second line of the character string 52 indicates that the connection server of the notification destination terminal specified in the character string 52 is the relay server 2B. The third to fifth lines of the character string 52 indicate that the notification destination terminals are terminals B1 to B3. The second line of the character string 53 indicates that the connection server of the notification destination terminal specified in the character string 53 is the relay server 2C. The third line of the character string 53 indicates that the notification destination terminal is the terminal C1. As described above, the database server 1 includes notification destination information and relay information for a plurality of notification destination terminals in one response message. Although not shown in FIG. 7, the database server 1 according to the present embodiment includes an identifier corresponding to each of the plurality of notification destination terminals in the response message (see S31 in FIG. 6).

  Returning to the description of FIG. When the relay server 2A receives the response message from the database server 1, the relay server 2A specifies the connection server (the relay server 2B and the relay server 2C) indicated by the relay information included in the message. The relay server 2A transmits a status notification “NOTIFY” for notifying the presence information of the terminal 3A to the identified connection server (S32, S33). The relay server 2A includes notification destination information and identifiers for one or more notification destination terminals connected to the connection server in the “NOTIFY” message. Note that, when the relay server 2A includes the own device in the connection server indicated by the relay information received from the database server 1 (when there is a notification destination terminal connected to the own device), the relay server 2A The notification destination information and the presence information of the terminal 3A are output to the external communication I / F 24 (see FIG. 3). The external communication I / F 24 of the relay server 2A transmits the presence information of the terminal 3A to the terminal 3 specified by the notification destination information among the terminals 3 connected to the own device. That is, the “output step” of the present invention transmits (outputs) a response message to another relay server 2 other than the own device, and outputs the notification destination information and presence information to the external communication I / F 24 of the own device. Processing.

  The relay server 2B that has received “NOTIFY” from the relay server 2A checks whether or not the identifiers (b1 to b3) included in the message match the identifiers stored in the relay server 2B (S34). The relay server 2B returns a response to the relay server 2A (S35). Only when the identifiers match, the relay server 2B transmits a status notification “NOTIFY” including presence information of the terminal 3A to the terminal B1, the terminal B2, and the terminal B3 that are the notification destination terminals (S36 to S38). Although not shown, the relay server 2B receives a response to “NOTIFY” from the terminals B1 to B3. Similarly, the relay server 2C confirms the identifier (c1) (S41), and returns a response to the relay server 2A (S42). If the identifiers match, the relay server 2C transmits “NOTIFY” to the terminal C1 (S43).

  As described above, according to the state notification method according to the first embodiment, the database server 1 transmits one message including notification destination information and relay information to any one of the plurality of relay servers 2. Only (see S31 in FIG. 6 and FIG. 7), the state of the notification source terminal can be notified to the notification destination terminal. Specifically, in the example shown in FIG. 6, there are two connection servers, the relay server 2B and the relay server 2C, but the database server 1 only needs to transmit a message to the relay server 2A. Even when the number of notification destination terminals is large, the database server 1 does not need to repeat message transmission / reception with a plurality of relay servers 2. Therefore, the communication system 100 can notify the notification destination terminal of the state of the notification source terminal without increasing the load on the database server 1.

  When the relay server 2 receives a response message (S31) to the status notification of the notification source terminal from the database server 1, the relay server 2 includes notification destination information for specifying a plurality of notification destination terminals in one message and transmits it to another relay server. (S32). Therefore, the communication system 100 can not only reduce the load on the database server 1 but also reduce the number of times messages are transmitted and received between the plurality of relay servers 2. Therefore, the communication system 100 can further reduce the load on the entire system.

  The database server 1 can include the notification destination information and the relay information in one response message for the notification of the state notification of the notification source terminal (S31). In other words, the database server 1 does not need to separately transmit a response message to the state notification and a message for transmitting the notification destination information and the relay information. Therefore, the communication system 100 can further reduce the number of times that the database server 1 transmits and receives messages. As a result, the load on the database server 1 is reduced.

  The relay server 2 acquires presence information to be relayed when relaying the presence information transmitted from the notification source terminal to the database server 1. When the relay server 2 transmits “NOTIFY” to another relay server 2, the presence information acquired when relaying the information is included in “NOTIFY”. Therefore, the database server 1 does not need to include presence information in the response message (S31) transmitted to the relay server 2. Therefore, the communication system 100 can reduce the amount of data transmitted and received.

  The relay server 2 that transmits presence information to the notification destination terminal confirms that “NOTIFY” received from the other relay server 2 is reliable information transmitted from the database server 1 via the other relay server 2. This can be determined using the identifier. Therefore, the communication system 100 can smoothly transmit and receive accurate information. The communication system 100 can smoothly communicate according to general-purpose SIP. The communication system 100 can easily realize the presence function using a general-purpose SIP message. The presence function can be easily realized without significantly changing the configuration of an existing communication system that performs communication according to SIP. The relay server 2 can execute both establishment of a session between a plurality of terminals 3 and control of a presence function. Therefore, the communication system 100 does not need to include a server for establishing a session and a server for controlling the presence function.

  In the first embodiment, the process in which the database server 1 stores information for specifying the notification destination terminal in the HDD 13 in S9 of FIG. 5 corresponds to the “registration step” of the present invention. The process in which the terminal 3 transmits a status notification to the database server 1 via the relay server 2 in S1 and S16 in FIG. 5 corresponds to a “status notification step”. The process in which the database server 1 transmits the response message in S20 of FIG. 5 and S31 of FIG. 6 corresponds to the “first transmission step”. The response message transmitted in S20 of FIG. 5 and S31 of FIG. 6 corresponds to “one information”, and the notification destination information included in the response message corresponds to “first notification destination information”. The processing in which the relay server 2 transmits “NOTIFY” to the other relay servers 2 in S32 and S33 in FIG. 6 and the processing in which the presence information and the notification destination information are output to the external communication I / F 24 of the own device. This corresponds to the “output step” of the invention. The notification destination information included in “NOTIFY” transmitted in S32 and S33 in FIG. 6 corresponds to “second notification destination information”. The process in which the relay server 2 transmits “NOTIFY” in S25 of FIG. 5 and S36 to S38 and S43 of FIG. 6 corresponds to a “second transmission step”.

  The process in which the relay server 2 acquires presence information in S2 and S17 in FIG. 5 corresponds to a “first acquisition step”. The process in which the database server 1 and the relay server 2 store the common identifier in S10 and S12 in FIG. 5 corresponds to a “storage control step”. The identifiers included in the messages in S20 and S22 in FIG. 5 and S31, S32, and S33 in FIG. 6 correspond to “identifier information”.

  The CPU 10 of the database server 1 that stores information specifying the notification destination terminal in the HDD 13 in S9 of FIG. 5 functions as the “registration means” of the present invention. The CPU 30 of the terminal 3 that transmits the status notification to the database server 1 via the relay server 2 in S1 and S16 in FIG. 5 functions as “status notification means”. The CPU 10 of the database server 1 that transmits the response message in S20 of FIG. 5 and S31 of FIG. 6 functions as a “first transmission unit”. The CPU 20 of the relay server 2 that performs the process of transmitting “NOTIFY” to the other relay server 2 in S32 and S33 of FIG. 6 and the process of outputting the presence information and the notification destination information to the external communication I / F of its own device. , Function as “output means” of the present invention. The CPU 20 of the relay server 2 that transmits “NOTIFY” in S25 of FIG. 5 and S36 to S38 and S43 of FIG. 6 functions as “second transmission means”.

  A state notification method executed by the communication system according to the second embodiment of the present invention will be described with reference to FIG. In the communication system according to the second embodiment, the transmission destination of the message including the notification destination information and the relay information (“one information” in the present invention) is selected based on the processing information of each relay server 2. This is different from the first embodiment. Further, the message transmitted from the database server 1 to the relay server 2 includes presence information of the notification source terminal, which is different from the first embodiment. Processing other than the above and the configuration of each device are the same as the processing and configuration in the first embodiment. Therefore, the configuration of each device is assigned the same number as the configuration in the first embodiment, and the description of the configuration is omitted.

  With reference to FIG. 8, the relay server selection process which the database server 1 which concerns on 2nd embodiment performs is demonstrated. The relay server selection process is executed by the CPU 10 of the database server 1 when the database server 1 receives a status notification (for example, S18 in FIG. 5) transmitted from the notification source terminal via the relay server 2. In the relay server selection process, first, a status notification message is received (S101). The presence information of the notification source terminal included in the received message is stored in the presence information storage area 131 (see FIG. 2) (S102). Notification destination information for specifying a notification destination terminal, relay information for specifying a connection server, and an identifier corresponding to each notification destination terminal are acquired (S103).

  Processing information of each relay server 2 in the communication system is acquired from the HDD 13 (S104, S105). Specifically, the time at which a message including notification destination information and relay information (hereinafter referred to as a “status notification request message”) was previously transmitted to each relay server 2 is acquired as processing information (S104). Further, when each relay server 2 has received the status notification request message last time, the number N of messages transmitted from each relay server 2 to the other relay server 2 and the terminal 3 is acquired as processing information (S105). The previous transmission time acquired in S104 and the previous transmission message count N acquired in S105 are stored in the HDD 13 in S113 (described later) of the relay server selection process executed last time.

  The number n of messages transmitted this time is calculated for each of the plurality of relay servers 2 (S106). The number n of messages to be transmitted this time is the number of messages that the relay server 2 will transmit when it is assumed that the status notification request message has been transmitted to the relay server 2. Specifically, the current transmission message number n of the relay server 2A that is one of the plurality of relay servers 2 is the number of notification destination terminals connected to the relay server 2A and the relay servers other than the relay server 2A. 2 is the sum of the number of relay servers 2 to which at least one notification destination terminal is connected (the number of connection servers other than the relay server 2A). The CPU 10 calculates the number n of current transmission messages of each relay server 2 using the notification destination information and the relay information acquired in S103. Next, an elapsed time T from the previous transmission time acquired in S104 is calculated for each relay server 2 (S107).

Whether or not there is a relay server 2 that satisfies the following expression (1) is searched using the average time t required for the process of transmitting a message once (S108). Information on the average time t is stored in the HDD 13 in advance.
(T−N · t) ≧ 0 (1)
It is determined that the relay server 2 that satisfies the condition of Expression (1) has already finished the process of transmitting a message. It is determined whether or not a relay server 2 (denoted as “corresponding server” in the figure) that satisfies the condition of Expression (1) has been searched (S109). When the relay server 2 that satisfies the condition is searched (S109: YES), among the searched relay servers 2, the relay server 2 with the smallest value of the number n of current transmission messages is the destination of the status notification request message. The relay server 2 is selected (S110).

When the relay server 2 that satisfies the condition of the expression (1) is not searched (S109: NO), the relay server 2 that minimizes the time calculated by the following expression (1) The destination relay server 2 is selected (S111).
((N + n) · t−T) (2)
The time calculated by the equation (2) is the time required to finish all the previous message transmission processing and the current message transmission processing. When a plurality of relay servers 2 exist as candidates in the processing of S110 or S111, one of the plurality of candidates may be selected as the transmission destination relay server 2. Specifically, the relay server 2 with the longest elapsed time T may be selected, or one relay server 2 may be selected at random using a random number or the like.

  When the relay server 2 is selected, a status notification including the presence information included in the status notification message received in S101 and the notification destination information, relay information, and identifier acquired in S103 is sent to the selected relay server 2. A request message is transmitted (S112). In association with each relay server 2, the value of n calculated in S106 is stored in the HDD 13 as the number N of previously transmitted messages. The current time is stored in the HDD 13 as the previous transmission time of the selected relay server 2 (S113). The process ends. The relay server 2 according to the second embodiment includes the presence information included in the status notification request message in “NOTIFY” transmitted in S22 of FIG. 5 and S32 and S33 of FIG.

  As described above, according to the status notification method according to the second embodiment, the database server 1 can transmit the status notification request message to the relay server according to the information on the processing executed by each relay server 2. 2 can be selected. Therefore, the communication system can prevent the processing load from being biased toward a specific relay server 2 in the system. Specifically, the database server 1 can transmit a status notification request message to the relay server 2 that is expected to be able to finish the message transmission process earliest. Therefore, the communication system can minimize the delay in notification of presence information. The communication system according to the second embodiment includes the presence information in the status notification request message transmitted from the database server 1 to the relay server 2, so that the presence information can be reliably notified to the notification destination terminal.

  In the second embodiment, the process in which the database server 1 acquires information in S104 and S105 in FIG. 8 corresponds to the “second acquisition step” of the present invention. The previous transmission time acquired in S104 and the previous transmission message count N acquired in S105 correspond to the “processing information” of the present invention. The status notification request message corresponds to “one information” of the present invention. The process in which the database server 1 selects the relay server 2 in S106 to S111 in FIG. 8 corresponds to a “selection step”.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications are possible. The communication system of the above-described embodiment uses a SIP message when transmitting / receiving some information. However, the present invention can also be realized without using a SIP message. The relay server 2 may not operate as a SIP proxy server.

  The relay server 2 according to the above embodiment includes all notification destination information and identifiers regarding a plurality of notification destination terminals in “NOTIFY” transmitted to other relay servers 2 in S32 of FIG. As a result, the communication system can reduce the number of messages transmitted and received between the plurality of relay servers 2. However, the relay server 2 may separately transmit the notification destination information and the identifier regarding each of the notification destination terminals to other relay servers 2. Even in this case, since the communication system can reduce the load on the database server 1, the presence function can be executed smoothly.

  In S32 and S33 of FIG. 6, the relay server 2 according to the embodiment transmits only “NOTIFY” including only the notification destination information and identifier of the notification destination terminal connected to the transmission destination relay server 2. . However, the relay server 2 may include the notification destination information and the identifier included in the message received from the database server 1 as they are in “NOTIFY”. That is, the content of “first notification destination information” and the content of “second notification destination information” according to the present invention may be the same. In this case, the relay server 2 that has received “NOTIFY” identifies the notification destination terminal connected to its own device from the notification destination information included in the received “NOTIFY”, and provides presence information to the identified notification destination terminal. Just send it.

  The relay server 2 according to the first embodiment acquires presence information when relaying presence information transmitted from a notification source terminal. The relay server 2 includes the presence information acquired in advance in “NOTIFY” transmitted to the other relay server 2. As a result, the relay server 2 can reduce the data amount of the transmitted / received message. However, the database server 1 according to the first embodiment may include the presence information of the notification source terminal in the response message returned to the relay server 2 as in the second embodiment. The relay server 2 may include the presence information included in the response message received from the database server 1 in “NOTIFY” transmitted to the other relay server 2.

  The database server 1 according to the second embodiment acquires the previous transmission time and the previous transmission message number N for each relay server 2 as processing information, and selects one of the relay servers 2. However, the information acquired by the database server 1 as processing information and the selection method of the relay server 2 can be changed. For example, the database server 1 acquires the number of notification destination terminals connected to each relay server 2 as processing information. The smaller the number of connected notification destination terminals, the lower the processing load on the relay server 2. Therefore, the database server 1 may select the relay server 2 having the smallest number of connected notification destination terminals as the transmission destination relay server 2 of the status notification request message.

  The database server 1 and the relay server 2 according to the embodiment transmit the identifier itself in a message. However, the database server 1 and the relay server 2 may transmit the message including information for specifying the identifier instead of the identifier itself. For example, the identifier may be encrypted using a public key encryption method, a challenge response method, or the like, and the encrypted code may be included in the message. As a result, the communication system can reduce the possibility that the identifier leaks outside the system. In this case, the encrypted code corresponds to “identifier information” of the present invention.

1 Database server 2 Relay server 3 Terminal 10 CPU
13 HDD
20 CPU
23 HDD
30 CPU
100 communication system

Claims (9)

A plurality of terminals, a database server capable of managing presence information indicating the state of each of the plurality of terminals, and a plurality of relays for relaying messages between at least one of the plurality of terminals and the database server A state notification method performed in a communication system including a server,
A registration step in which the database server registers in the storage means information identifying one or more notification destination terminals that are notification destinations of the states of the plurality of terminals;
A status notification step in which a notification source terminal that is one of the plurality of terminals transmits presence information of the notification source terminal to the database server via a connected relay server;
The database server that has received the presence information of the notification source terminal transmitted in the status notification step, first notification destination information for specifying the notification destination terminal based on the information registered in the registration step; A first transmission step of transmitting one piece of information including relay information for specifying a relay server connected to the notification destination terminal to any of the plurality of relay servers;
The second notification in which the relay server that has received the one information transmitted in the first transmission step identifies the notification destination terminal identified by the first notification destination information to the relay server identified by the relay information An output step of outputting destination information and presence information of the notification source terminal;
A second transmission step in which the relay server that has input the information output in the output step transmits the input presence information to a terminal identified by the second notification destination information among terminals connected to the relay server; A state notification method characterized by comprising:   In the output step, when the plurality of notification destination terminals are specified by the first notification destination information and two or more of the plurality of notification destination terminals are connected to one relay server in the output step, The status notification method according to claim 1, wherein one second notification destination information that specifies two or more notification destination terminals is output to the relay server.   In the first transmission step, the database server sends the first information including the first notification destination information and the relay information to a relay server that relays the presence information together with a response to the presence information being received. The status notification method according to claim 1, wherein the status notification method is transmitted. A relay server that relays the presence information of the notification source terminal in the state notification step further includes a first acquisition step of acquiring the presence information to be relayed when relaying the presence information;
The status notification method according to claim 3, wherein, in the output step, the relay server outputs the presence information acquired in the first acquisition step. A second acquisition step in which the database server that has received the presence information of the notification source terminal transmitted in the state notification step acquires processing information that is information relating to processing executed by each of the plurality of relay servers; ,
The database server that has acquired the processing information in the second acquisition step has a plurality of destination relay servers that transmit the one information including the notification destination information and the relay information based on the acquired processing information. A selection step of selecting from among the relay servers of
The status notification method according to claim 1 or 2, wherein, in the first transmission step, the database server transmits the one information to the relay server selected in the selection step. In the first transmission step, the database server transmits presence information of the notification source terminal included in the one information,
6. The status notification method according to claim 1, wherein in the output step, the relay server outputs the presence information included in the received one information. Each of the relay servers and the database server further includes a storage control step of storing a common identifier between each of the relay servers and the database server in a storage unit,
In the first transmission step, the database server includes identifier information related to an identifier common to the relay server specified by the relay information, and transmits the identifier information in the one information.
In the output step, the relay server that has received the one information transmitted in the first transmission step outputs the identifier information included in the one information together with the second notification destination information and the presence information. ,
In the second transmission step, if the relay server that has input the information output in the output step has a common identifier with the database server, the input presence information The state notification method according to any one of claims 1 to 6, characterized in that: Each of the plurality of terminals operates as a SIP client that communicates with another terminal in accordance with SIP (Session Initiation Protocol),
The status notification method according to claim 1, wherein the relay server operates as a SIP proxy server that establishes a SIP session between the plurality of terminals. A plurality of terminals, a database server capable of managing presence information indicating the state of each of the plurality of terminals, and a plurality of relays for relaying messages between at least one of the plurality of terminals and the database server A communication system comprising a server,
In the database server, registration means for registering in the storage means information identifying one or more notification destination terminals that are notification destinations of the states of the plurality of terminals,
In the notification source terminal that is one of the plurality of terminals, status notification means for transmitting presence information of the notification source terminal to the database server via a relay server connected to the notification source terminal; ,
In the database server, when receiving the presence information of the notification source terminal transmitted by the state notification unit, a first notification for specifying the notification destination terminal based on the information registered by the registration unit First transmission means for transmitting one piece of information including destination information and relay information for specifying a relay server connected to the notification destination terminal to any of the plurality of relay servers;
In each of the plurality of relay servers, when the one information transmitted by the first transmission unit is received, a notification specified by the first notification destination information is sent to the relay server specified by the relay information Output means for outputting second notification destination information for specifying a destination terminal, and presence information of the notification source terminal;
In each of the plurality of relay servers, when the information output by the output unit is input, presence information input to a terminal specified by the second notification destination information among terminals connected to the relay server And a second transmission means for transmitting the communication system.

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