JP4187036B2 - Relay server - Google Patents

Description

  The present invention relates to a technology in which communication terminals in a local area network (LAN) communicate with each other across a wide area network (WAN), and more particularly to a communication technology between relay servers that relay the communication.

  Using a call control protocol such as SIP (Session Initiation Protocol) or DDNS (Dynamic Domain Name System), communication terminals existing in different LANs can communicate directly over the WAN. This is a so-called VPN (Virtual Private Network) technology, and different LANs at remote locations can be used as if they were directly connected networks.

  By using such a technique, for example, it is possible to connect a LAN between a head office and a branch office and perform communication across the Internet between terminals connected to each LAN.

  In Patent Document 1, communication terminals connected to different LANs can communicate with each other over the Internet. In this technique, different communication terminals connected to different LANs log in to a relay server connected to the Internet via a gateway, and establish a communication path with the relay server. Yes. By using this communication path, communication between communication terminals can be performed across the Internet. The technique of Patent Document 1 is a technique that enables communication between LANs using a relay server existing on a WAN.

JP 2002-217938 A

  When using SIP, account information of each communication terminal is generally registered in the SIP server. That is, each communication terminal issues a REGISTER method to the SIP server, thereby registering account information in the SIP server. When a communication request specifying an account of another communication terminal is generated from a certain communication terminal, the SIP server relays communication for establishing a session according to the registered account information.

  When communication is performed between a large number of LANs using SIP, a large amount of account information is registered in the SIP server, which increases the load on the server. In other words, in order to connect a large number of LANs and perform communication between the large number of LANs, conventionally, the accounts arranged in all the LANs are registered in a server that manages them in a unified manner. So the server load was heavy.

  In addition, when a communication terminal existing in the network is moved from one LAN to another, the account information of the already registered communication terminal becomes unnecessary, and a new one is newly created at the destination. Since it was necessary to register the account information of the communication terminal, it was difficult to manage and time-consuming, and it was not possible to deal with the movement of the communication terminal in real time.

  In view of the above problems, the present invention provides a technology that enables communication between communication terminals arranged in different LANs while realizing reduction of server load, dynamic response to movement of communication terminals, and the like. The purpose is to do.

  In order to solve the above-described problem, the relay server according to the first aspect of the present invention is a relay server arranged in a local area network and capable of communicating with an external server arranged in a wide area network. Specify the local account information registration means for registering the account information of the communication terminal, the means for registering the account information of its own device in the external server, and another relay server registered in the external server, Means for establishing a communication session for relay that can be directly communicated with, means for exchanging account information held by other relay servers, local account information registration means, and other relay servers. When there is a change in the account information that is retained, send the changed account information. When a change request setting means to request and a communication request specifying an account of another communication terminal from a communication terminal in the local area network are received, the account specified from the account information exchanged with another relay server is registered. Means for determining a relay server and relaying communication data between communication terminals through a relay communication session with the corresponding relay server.

  According to the second aspect of the present invention, in the relay server according to the first aspect, when a communication session for relay that can directly communicate with another relay server is established, the account information of the other relay server is changed. In this case, the relay server is characterized in that it can be specified whether or not to request transmission of account information after change.

  The invention according to claim 3 is the relay server according to claim 1 or 2, wherein when the account information is registered by the communication terminal in the local area network, The relay server is characterized in that it can be specified whether or not to include it in the account information transmitted to the relay server.

  According to the relay server of the present invention, a communication terminal connected to a LAN can communicate with a communication terminal connected to another LAN over the Internet.

  When the account information of the communication terminal in the LAN is exchanged with another relay server, and the changed account information is changed, the account information after the change is notified every time. Even if there is a change in registered account information due to a registration request, movement, etc., the account information of the communication terminal is automatically updated in real time and can be handled dynamically.

  When registering with the relay server, each communication terminal can specify whether or not to notify other relay servers of account information changed by this, and if it is specified not to notify, the existence of its own device is concealed. Can be kept in a state. Further, when establishing a relay communication session with another relay server, the relay server can specify whether to request a change notification of account information by a notification event.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall view of a communication system according to the present embodiment. This communication system includes the Internet 3 and two LANs 1 and 2 connected to the Internet 3. LANs 1 and 2 are networks constructed in physically separated locations. For example, LAN 1 is a local network built in a head office building, LAN 2 is a local network built in another branch office building, and these two LANs 1 and 2 are connected to the Internet 3 which is a global network. Yes.

  As shown in the figure, communication terminals 11 and 12 are connected to the LAN 1. Each of the communication terminals 11 and 12 is assigned a private IP address. As described above, generally, a terminal connected to a LAN is assigned a private IP address that is uniquely managed only within the LAN. A relay server 13 is connected to the LAN 1. The relay server 13 is connected to the LAN 1 and also connected to the Internet 3. The relay server 13 is assigned a private IP address for the LAN interface and a global IP address for the WAN interface.

  Communication terminals 21 and 22 assigned with private IP addresses are connected to the LAN 2. A relay server 23 is connected to the LAN 2. The relay server 23 is connected not only to the LAN 2 but also to the Internet 3 and is given a private IP address for the LAN interface and a global IP address for the WAN interface.

  Further, a SIP server 4 is connected to the Internet 3. The SIP server 4 registers a function as a proxy server that relays SIP methods and responses, and accounts of the relay servers 13 and 23 when the relay servers 13 and 23 perform communication using SIP (Session Initiation Protocol). A function as a SIP registrar server.

  On the other hand, the relay server 13 connected to the LAN 1 has a function as a SIP registrar server that registers accounts of the communication terminals 11 and 12 connected to the LAN 1 using SIP.

  That is, as shown in FIG. 2, the relay server 13 functions as a SIP registrar server that registers an account based on a registration request (REGISTER) received from the communication terminals 11 and 12 in relation to the communication terminals 11 and 12. In the relationship with the SIP server 4, it functions as a client that transmits an account registration request (REGISTER) to the SIP server 4.

  Similarly, the relay server 23 connected to the LAN 2 also has a function as a SIP registrar server that registers accounts of the communication terminals 21 and 22 connected to the LAN 2 using SIP.

  That is, as shown in FIG. 2, the relay server 23 functions as a SIP registrar server that registers an account based on a registration request (REGISTER) received from the communication terminals 21 and 22 in relation to the communication terminals 21 and 22. In the relationship with the SIP server 4, it functions as a client that transmits an account registration request (REGISTER) to the SIP server 4.

  FIG. 3 is a functional block diagram of the relay servers 13 and 23. Since the relay servers 13 and 23 have the same function, they will be described with reference to the same drawing. The relay servers 13 and 23 include a LAN interface 101, a WAN interface 102, a communication control unit 103, and a local account information database 104.

  The LAN interface 101 is an interface that communicates with a communication terminal connected to a LAN using a private IP address. That is, the relay server 13 communicates with the communication terminals 11, 12, etc. using the LAN interface 101, and the relay server 23 communicates with the communication terminals 21, 22, etc. using the LAN interface 101.

  The WAN interface 102 is an interface that communicates with the SIP server 4 connected to the Internet 3, which is a global network, and other communication servers and communication terminals connected to the Internet 3 using a global IP address. In the present embodiment, the relay server is configured to include a WAN interface. However, the router may be connected to the WAN, and the relay server may be installed under the router.

  The communication control unit 103 is a processing unit that controls various communications performed via the LAN interface 101 and the WAN interface 102. The communication control unit 103 controls various communication processes according to protocols such as TCP / IP, UDP, and SIP.

  One function of the communication control unit 103 is to receive an account registration request (REGISTER) from a communication terminal connected to the LAN and register the account information of the communication terminal in the local account information database 104. For example, the relay server 13 receives an account registration request (REGISTER) from the communication terminal 11 and registers the account information of the communication terminal 11 in the local account information database 104.

  The communication control unit 103 also exchanges account information with other relay servers, transmits account information held by the own device to the relay server, and receives account information held by the relay server. Then, a process of registering in the local account information database 104 of the own device is executed. Then, when a change occurs in the account information held by the relay server, the change notification setting that requests that the change notification and the account information after the change be continuously transmitted is sent to another relay server. If the account information of the own device is changed, a process of transmitting the change notification and the changed account information to the relay server in which the change notification setting is performed is executed. This processing is performed in SIP using notification events by the methods of SUBSCRIBE and NOTIFY, as will be described later. In the notification event, a period for executing the notification event can be set. When the change notification setting using the notification event is performed by transmitting the SUBSCRIBE method by an operator operation or the like, the account of the relay server on the side that has received the SUBSCRIBE method is subsequently executed during the period in which the notification event can be executed. When a change occurs in the information, the NOTIFY method notifies the change server and the notification of new account information to the relay server that has transmitted the SUBSCRIBE method.

  The notified account information is registered in the local account information database 104. If there is a change, the contents after the change are registered and continuously updated.

  When a communication terminal connected to the LAN transmits an account registration request (REGISTER) to a relay server, the account information registered in the relay server is changed accordingly. When a change occurs in the account information, a series of processing related to the change of the account information is executed according to the previous change notification setting. At the time of this registration request (REGISTER), the account information to be registered is changed. It can be specified whether or not to include in account information transmitted to other relay servers. That is, the communication terminal can keep the presence of its own device in a secret state with respect to other LAN relay servers and the like.

  In addition, when a relay server establishes a communication session for relay that can communicate directly with another relay server using the INVITE method, if a change occurs in the account information of the other relay server, a change notification and a post-change You can specify whether to request transmission of account information. That is, it is possible to select whether or not to request a change notification of account information from the other relay server.

  Furthermore, when the communication control unit 103 receives a communication request specifying an account of a communication terminal in another LAN from a communication terminal in the same LAN, the account specified from the account information exchanged with another relay server is registered. A relay server is determined, and control is performed to relay communication data between communication terminals through a relay communication session with the corresponding relay server.

  The communication control unit 103 also has a function of transmitting a registration request (REGISTER) for registering an account of the relay server itself to the SIP server 4.

  In addition, the communication control unit 103 has a function of connecting and maintaining a tunneling session with the relay servers 13 and 23 on the other side. That is, the relay servers 13 and 23 can establish a tunneling session between the relay servers 13 and 23 by transmitting the SIP INVITE method from either one. The communication control unit 103 of the relay servers 13 and 23 can relay communication data between the communication terminals connected to the LANs 1 and 2 by maintaining the established tunneling session.

  In other words, since private accounts are assigned to the communication terminals connected to the LANs 1 and 2, as described later, when communicating with communication terminals located on different LANs 1 and 2, the private terminals of the destinations are connected. An account will be specified. However, communication data such as an SIP command in which this private account is designated is encapsulated between the relay servers 13 and 23 and relayed to the other relay server 13 and 23. The receiving side relay servers 13 and 23 take out the relayed SIP command, and relay-transmit the communication data designating the private account to the corresponding communication terminal.

  FIG. 4 is a functional block diagram of the SIP server 4. The SIP server 4 includes a WAN interface 41, a communication control unit 42, and a relay server account information database 43 as shown in the figure.

  The WAN interface 41 is an interface that communicates with a server and a terminal connected to the Internet 3 using a global IP address. The SIP server 4 can communicate with the relay servers 13 and 23 using the WAN interface 41.

  The communication control unit 42 is a processing unit that controls various communications performed via the WAN interface 41. The communication control unit 42 controls communication processing according to protocols such as TCP / IP, UDP, and SIP.

  One function of the communication control unit 42 is to receive an account registration request (REGISTER) from a relay server connected to the Internet 3 and register the account information of the relay server in the relay server account information database 43. is there. For example, the SIP server 4 receives an account registration request (REGISTER) from the relay server 13 and registers the account information of the relay server 13 in the relay server account information database 43.

  In addition, the communication control unit 42 has a function of relaying communication data such as various SIP methods and responses transmitted from the relay servers 13 and 23 to the other relay server.

  The flow of communication processing in the communication system configured as described above will be described with reference to the processing sequence diagrams of FIGS. FIG. 5 shows a sequence from step S1 to step S8, and FIG. 6 shows a sequence from step S9 to step S11 following the sequence.

  First, the relay server 13 transmits an account registration request (REGISTER) to the SIP server 4 (step S1). As shown in FIG. 5, here, the relay server 13 makes a registration request for its own account (SIP: relay-server1@sip.srv). The SIP server 4 returns an OK response to the relay server 13 and registers the account of the relay server 13 and the global IP address of the relay server 13 in the relay server account information database 43 in association with each other. When performing password authentication, a relay server account and a password are registered in advance in the relay server account information database 43. In this case, the user transmits a password in accordance with the registration request. If password authentication is successful, an account is registered in association with the IP address.

  Subsequently, the relay server 23 transmits an account registration request (REGISTER) to the SIP server 4 (step S2). Here, the relay server 23 makes a registration request for its own account (SIP: relay-server2@sip.srv). The SIP server 4 returns an OK response to the relay server 23 and registers the account of the relay server 23 and the global IP address of the relay server 23 in association with each other in the relay server account information database 43. Similarly, password authentication may be performed.

  Next, the communication terminal 11 transmits an account registration request (REGISTER) to the relay server 13 (step S3). Here, the communication terminal 11 makes a registration request for its own count (SIP: 0001 @ privatesip1). The relay server 13 performs an OK response, and registers the account of the communication terminal 11 and the private IP address of the communication terminal 11 in the local account information database 104 in association with each other. When performing password authentication, the account and password of the communication terminal are registered in advance in the local account information database 104. In this case, the user transmits a password in accordance with the registration request. If password authentication is successful, an account is registered in association with the IP address.

  Next, the communication terminal 21 transmits an account registration request (REGISTER) to the relay server 23 (step S4). Here, the communication terminal 21 makes a registration request for its own account (SIP: 0002 @ privatesip2). The relay server 23 performs an OK response, and registers the account of the communication terminal 21 and the private IP address of the communication terminal 21 in the local account information database 104 in association with each other. In this case, password authentication may be performed in the same manner.

  As described above, account registration of the relay servers 13 and 23 to the SIP server 4 is completed, and account registration of the communication terminals 11 and 21 to the relay servers 13 and 23 is completed.

  Next, the relay server 13 transmits a connection request command (INVITE method) for the relay server 23 to the SIP server 4 (step S5). In this INVITE method, the account (SIP: relay-sever2@sip.srv) of the relay server 23 that is the connection request destination is specified. The SIP server 4 acquires the global IP address of the relay server 23 by referring to the relay server account information database 43. Then, the SIP server 4 relays the INVITE method transmitted from the relay server 13 to the relay server 23.

  In this way, when the connection request command is transmitted from the relay server 13 to the relay server 23, an OK response is transferred from the relay server 23 to the relay server 13 via the SIP server 4. When the connection request command is accepted in this way, a tunneling session is established between the relay servers 13 and 23 (step S6).

  The processes from step S1 to step S6 are generally performed as an initial network setting by an operator. The operator performs an operation of registering in the SIP server 4 a relay server arranged in a LAN to be connected over the Internet 3. In addition, an operation of registering a communication terminal to be communicated over the Internet 3 in the relay server is performed.

  Next, the relay server 13 uses the SUBSCRIBE method for the relay server 23 to perform change notification setting using the notification event with the relay server 23 (step S7). As a result, whenever a change occurs in the account information held by the relay server 23, the change notification and the changed account information are notified from the relay server 23 to the relay server 13 by the NOTIFY method. This communication is performed via the SIP server 4. Alternatively, the SUBSCRIBE method may be directly transmitted to the relay server 23 without going through the SIP server.

  The contents of the local account information LA1 notified from the relay server 23 to the relay server 13 by the NOTIFY method based on the SUBSCRIBE method in step S7 are shown in the sequence diagram of FIG.

  The local account information LA1 includes information on a communication terminal connected to the LAN 2 in which the relay server 23 is disposed, and the communication terminal that has registered an account with the relay server 23. In the current state, since the communication terminal 21 has registered an account for the relay server 23, the account information (SIP: 0002 @ privatesip2) of the communication terminal 21 is recorded in the local account information LA1. Yes.

  The relay server 13 that has received the local account information LA1 registers the information in the local account information database 104 of its own device. However, the received account information is registered in association with the account information of the relay server that is the transmission source of the account information. In this case, the communication terminal 21 account (SIP: 0002 @ privatesip2) is registered in association with the relay server 23 account (SIP: relay-server2@sip.srv).

  Next, the relay server 23 uses the SUBSCRIBE method for the relay server 13 to perform change notification setting using the notification event with the relay server 13 (step S8). As a result, whenever a change occurs in the account information held by the relay server 13, the change notification and the account information after the change are notified from the relay server 13 to the relay server 23 by the NOTIFY method. This communication is performed via the SIP server 4. Alternatively, the SUBSCRIBE method may be transmitted directly to the relay server 13 without going through the SIP server.

  The contents of the local account information LA2 notified from the relay server 13 to the relay server 23 by the NOTIFY method based on the SUBSCRIBE method in step S8 are shown in the sequence diagram of FIG. The local account information LA2 includes information on a communication terminal connected to the LAN 1 in which the relay server 13 is arranged, and the communication terminal that has registered an account with the relay server 13. The relay server 23 registers the information in the local account information database 104 of its own device. In this case, the account (SIP: 0001 @ privatesip1) of the communication terminal 11 and the account (SIP: relay-server1@sip.srv) of the relay server 13 are associated with each other in the local account information database 104. Register.

  In this way, the relay server 13 and the relay server 23 exchange the local account information LA1 and LA2, and register the acquired information in the local account information database 104, respectively. The communication terminal 11 connected to the LAN 1 can refer to the local account information database 104 managed by the relay server 13 by accessing the relay server 13. For example, the user of the communication terminal 11 can refer to the contents of the local account information database 104 by an operation of referring to the address book. Similarly, the communication terminal 21 connected to the LAN 2 can refer to the local account information database 104 managed by the relay server 23.

  Next, a description will be given of a case where there is a change in account information registered due to a registration request, movement, etc. of the communication terminal.

  For example, as shown in FIG. 6, it is assumed that an account registration request (REGISTER) is newly transmitted from the communication terminal 12 to the relay server 13 (step S9). Specifically, the communication terminal 12 requests the relay server 13 to register its own account (SIP: 0003 @ privatesip1). The relay server 13 performs an OK response, and registers the account of the communication terminal 12 and the private IP address of the communication terminal 12 in the local account information database 104 in association with each other. Again, password authentication may be performed.

  In the relay server 13, when the account of the communication terminal 13 is newly registered, the account information held by the local account information registration unit is changed. As a result, the local account information including the notification of the change and the account information after the change is relayed by the NOTIFY method based on the change notification setting (step S8) that has occurred with the relay server 23 first. The server 13 notifies the relay server 23 (step S10).

  The contents of the local account information LA3 notified from the relay server 13 to the relay server 23 by the NOTIFY method based on the SUBSCRIBE method in step S8 are shown in the sequence diagram of FIG. This local account information LA3 is a communication terminal connected to the LAN 1 where the relay server 13 is arranged, and information (SIP: 0001 @ privatesip1) of the communication terminal that has registered an account with the relay server 13. Information (SIP: 0003 @ privatesip1) of the newly registered communication terminal is included in a state in which the information is associated with the relay server 13 account (SIP: relay-server1@sip.srv).

  The relay server 23 registers the received account information in the local account information database 104 of the own device, and updates the information after the change.

  Next, it is assumed that the user of the communication terminal 21 needs to communicate with the communication terminal 12. The user of the communication terminal 21 accesses the relay server 23 and refers to the address book. Then, the communication process to the communication terminal 12 is executed by designating the account (SIP: 0003 @ privatesip1) of the communication terminal 12. Thereby, the SIP command which makes the destination the communication terminal 12 from the communication terminal 21 is transmitted to the relay server 23 (step S11).

  When the relay server 23 receives the SIP command specifying the communication terminal 12 as the destination account, the relay server 23 refers to the local account information database 104 and identifies the relay server in which the destination account is registered. In this case, since the account of the communication terminal 12 is registered in association with the relay server 13, the relay server 13 is selected as a relay destination.

  Thereby, the relay server 23 directly transfers the SIP command received from the communication terminal 21 to the relay server 13 using the tunneling session (step S11.1). Further, the relay server 13 transfers the SIP command received from the relay server 23 to the communication terminal 12 (step S11.1.1). Through such a procedure, the SIP command transmitted from the communication terminal 21 is transferred to the communication terminal 12.

  When receiving the SIP command transmitted from the communication terminal 21, the communication terminal 12 returns a SIP response to the communication terminal 21. This response is directly transferred from the relay server 13 to the relay server 23 again using the tunneling session, and further transferred to the communication terminal 21 by the relay server 23.

  As described above, when a communication terminal connected to the LAN transmits an account registration request (REGISTER) to the relay server, a change occurs in the registered account information, and the registration information is automatically changed to each of the registration information. It will be shared between relay servers. Therefore, in order to enable the communication terminal to keep the existence of its own device in a concealed state, the account information registered at the time of registration request (REGISTER) of its own device is changed to account information to be transmitted to another relay server. Whether to include or not can be specified. For example, in the previous step S9, when the communication terminal 12 specifies that the account information to be registered is not included in the account information to be transmitted to other relay servers when making a registration request (REGISTER), the previous step S10 does not occur. The account of the communication terminal 12 is not notified to other relay servers.

  In addition, when a relay server establishes a communication session for relay that can communicate directly with another relay server using the INVITE method, if a change occurs in the account information of the partner relay server, the change notification and the account after the change are made. It is possible to specify whether or not to make a request for transmitting information. For example, when the relay server 13 establishes a relay communication session with the relay server 23 in the previous step S5, if the account information of the partner relay server is changed, the change notification and the changed account information Is specified not to request transmission. In that case, the SUBSCRIBE method in step S7 is not transmitted. Alternatively, the SUBSCRIBE method having a very short effective period is transmitted, and the notification by the NOTIFY method is performed only once from the relay server 23 based on the SUBSCRIBE method. Even if a change occurs thereafter, the change notification or the like is not transmitted.

  In addition to this, when a communication terminal makes a registration request (REGISTER) to a relay server, whether or not to disclose its existence is realized by adding its attribute information (for example, PUBLIC / PRIVATE) to the registration request command. Is possible. Moreover, it is also possible to make the existence of itself public only to a specific relay server by adding attribute information (for example, PRIVATE = relay server 23).

  In the above example, the account information of the communication terminal is newly registered as a case where the account information is changed. However, the account information of the registered communication terminal may be deleted. Of course included.

  As described above, by using the communication system according to the present embodiment, a communication terminal connected to LAN 1 and LAN 2 can communicate with the communication terminal connected to the other LAN 1 and 2 over the Internet 3. Communication is possible.

  Since the relay server automatically establishes a communication path in real time, it can dynamically cope with the movement of a communication terminal between LANs.

  Each communication terminal can keep the existence of its own device in a concealed state when registering with the relay server as necessary. In addition, when constructing a relay route, it can be specified not to respond dynamically.

It is a network block diagram of the communication system which concerns on this Embodiment. It is a figure which shows the relationship between a communication terminal and a relay server, and the relationship between a relay server and a SIP server. It is a functional block diagram of a relay server. It is a functional block diagram of a SIP server. It is a sequence diagram of a communication process. It is a sequence diagram of a communication process.

Explanation of symbols

1, 2 LAN (local network)
3 Internet (global network)
4 SIP servers 11, 12, 21, 22 Communication terminals 13, 23 Relay server

Claims (3)

A relay server arranged in a local area network and capable of communicating with an external server arranged in a wide area network,
Local account information registration means for registering account information of communication terminals in the local area network;
Means for registering the account information of its own device in an external server;
A means for specifying another relay server registered in the external server and constructing a communication session for relay that can directly communicate with the other relay server;
Means for exchanging account information held by the local account information registration means with another relay server;
Change notification setting means for requesting other relay servers to transmit the account information after the change when the account information held by the relay server is changed,
When a communication request specifying an account of another communication terminal is received from a communication terminal in the local area network, the relay server in which the specified account is registered is determined from account information exchanged with another relay server, and the corresponding Means for relaying communication data between communication terminals through a communication session for relay with a relay server;
A relay server comprising: The relay server according to claim 1,
Whether to request that the account information after the change be requested when the account information of the other relay server is changed when building a communication session for relay that can communicate directly with other relay servers A relay server that can be specified. In the relay server according to claim 1 or 2,
When the account information is registered by the communication terminal in the local area network, it is possible to specify whether or not the account information to be registered is included in the account information transmitted to another relay server. server.

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