JP4665063B2 - COMMUNICATION SYSTEM, TERMINAL REGISTRATION METHOD, AND SERVER - Google Patents

Description

  The present invention relates to a communication system that forms a session between terminals via, for example, an IP (Internet Protocol) network, and a server and a terminal registration method used in this system.

  In recent communication systems, it has become mainstream to form a session between terminals via an IP network. A typical example is a so-called VoIP (Voice over IP) system in which voice communication is performed using an IP network. In addition to well-known SIP (Session Initiation Protocol), Megaco (Media Gateway Control) or H.264 is used as the VoIP protocol. 248.

  Survivability needs to be considered in the operation of the communication system. Survivability is a term used in this technical field to express the ability or nature of a system that can continue to operate services to users even if a failure occurs. There are several levels of survivability, for example level 1 survivability.

  When the IP telephone system includes a plurality of servers and endpoints (Endpoints) as communication terminals, one of the servers is a home server (Home Server) and the other is a backup server (Backup Server) when viewed from each endpoint. ), It is considered that the endpoint is connected to the home server in normal time (when there is no failure). When an endpoint detects a failure of the home server due to a failure of KeepAlive, this endpoint immediately issues a connection request to the backup server, and thereafter continues to rely on the backup server at the connection destination. According to such a system configuration, the reliability of the system can be improved without duplicating the server itself. The survivability realized in this way is referred to as level 1 survivability. The server here is a so-called SIP server in SIP.

  By the way, in order for an endpoint to connect to a server, a procedure for issuing a login request message from the endpoint to the server is required. The endpoint obtains the IP address of the other party to which this message should be issued from a DHCP (Dynamic Host Configuration Protocol) server. However, since the DHCP server notifies the endpoint of a fixed IP address regardless of whether it is a home server or a backup server, login requests are concentrated on a specific server.

  When the server to which the login request is sent is a backup server for the sending end point (the end point cannot know this in advance), the following problem occurs. That is, in the existing technology, there is no way for the server side to distinguish whether the login request is based on level 1 survivability or not. If a connection is made to the backup server due to a login request that is not based on level 1 survivability (such as when the endpoint is turned on / off), the maintainer's manual is used to reconnect the endpoint to the original home server. Operation is required. Such a problem can occur not only in a system using SIP but also in a system using another protocol, and some countermeasure is desired.

  Patent Document 1 discloses a technology that can form an environment similar to level 1 survivability at first glance. This document discloses a technique for distributing a load by transferring a session from a SIP terminal to a low-load priority connection server by a distribution control unit (eg, [Summary]). However, in this document, as described in paragraph [0008], a technique is disclosed in which traffic transfer destinations are varied according to the load state of the SIP server, and the registration destinations of terminals (endpoints) are distributed. Not.

JP 2007-4361 A

As described above, in the existing technology, when the endpoint issues a login request to the backup server, there is no way for the server to distinguish whether the request is based on level 1 survivability or not. For this reason, the endpoint may be connected (registered) to an incorrect server, which may cause a problem in system operation. In addition, there is a need to eliminate this because it takes time and effort for the maintenance person to input a command in order to connect the endpoint to the original server. Even if a command is to be input by a process on the machine side, it is necessary to check the normality of the home server as a previous step, which increases the load on the system side. It is awaited to provide a technology in which each endpoint is connected from the beginning to the server that is the original connection partner.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a communication system capable of connecting individual end points to a server which is an original connection partner, a terminal registration method thereof, and a server.

  In order to achieve the above object, according to one aspect of the present invention, the communication system includes an endpoint capable of communication and a server that operates as a home server or a backup server for the endpoint. A transmission unit that transmits to the server a registration request with identification information for distinguishing whether or not the cause of the failure is based on the occurrence of a failure, and the server includes an identification assigned to the received registration request From the information, the identification unit that identifies whether or not the cause of the registration request is a failure, and if the local server is the home server for the endpoint of the received registration request, or When the server is a backup server and the cause of the registration request is the occurrence of the failure, it is determined that the registration of the endpoint is permitted And a registration processing unit that registers the end point with the own server when permitted by the determination unit, and instructs the end point to redirect the registration request when not permitted. A communication system is provided.

  By taking such means, the endpoint writes information indicating the cause of the request in the registration request and transmits it to the server. The server can determine whether the registration is permitted or not by reading this information.

  According to the present invention, it is possible to provide a communication system, a terminal registration method, and a server capable of connecting individual endpoints to a server that is an original connection partner.

1 is a system diagram showing an embodiment of an IP telephone system according to the present invention. The functional block diagram which shows embodiment of IPT # 1, # 2 of FIG. The functional block diagram which shows embodiment of SIP server #A of FIG. 1, #B. The figure which shows an example of the content of the management table 14a of FIG. The figure which shows an example of the sequence in the initial registration of IPT in embodiment of this invention. The figure which shows an example of the re-registration sequence of IPT at the time of the failure of a SIP server.

  FIG. 1 is a system diagram showing an embodiment of an IP telephone system according to the present invention. This system is formed by connecting SIP servers #A and #B and a plurality of IP terminals (IPT) # 1 and # 2 as end points to a common IP network 100. Of course, the number of IPTs is not limited to two, and many IPTs are connected to the IP network 100, and these IPTs are registered in one of the SIP servers #A and #B. Each of the SIP servers #A and #B performs control for forming a session between IPTs in the IP network 100.

  The IPTs # 1 and # 2 have a telephone communication function via a session formed in the IP network 100. Examples of this type of terminal include a multi-function telephone, a computer (soft phone) installed with voice call software, and a cellular phone terminal. Alternatively, it may be a terminal connected to a personal computer or PDA (Personal Digital Assistants) and having a function of transmitting and receiving multimedia data. Furthermore, a high-performance mobile phone called a smart phone is also in its category. A smartphone has both the function of a mobile terminal or a PHS terminal and the function of a PDA.

  The IP network 100 is, for example, a LAN (Local Area Network). Also connected to the IP network 100 is a DHCP (Dynamic Host Configuration Protocol) server 200 having functions such as issuing IP addresses and notifying IP address information of the SIP servers #A and #B.

  SIP servers #A and #B have a function of processing level 1 survivability. That is, one server system is configured by the SIP servers #A and #B, and this server system has a function of controlling a plurality of IPTs. That is, the SIP servers #A and #B are associated in advance for each IPT with either the home server or the backup server having a lower priority than the home server. This association is made, for example, by associating an IPT URL (Uniform resource Locator) with an identifier of each server.

  FIG. 2 is a functional block diagram showing an embodiment of IPTs # 1 and # 2 in FIG. The IPTs # 1 and # 2 include an interface unit 41, a display unit 40, a control unit 42, a keypad unit 43, and a memory 44 connected to the IP network 100 via the LAN cable 60. Among these, the display device 40 is an LCD (Liquid Crystal Display), and displays various messages. The keypad unit 43 includes soft keys, numeric keys, special keys, and the like, and accepts user input operations.

  The memory 44 is a rewritable semiconductor storage device such as a flash memory. The memory 44 holds, for example, the IP addresses of the servers #A and #B notified from the DHCP server 200 in the IPT startup routine. In addition, the memory 44 also stores the IPT's own URI, and the IPT requests registration from any SIP server under this URI.

  The control unit 42 includes a communication processing unit 42a and a SIP message processing unit 42b as processing functions related to the present invention. The communication processing unit 42a controls communication via the IP network 100. For example, in addition to controlling voice calls, the communication processing unit 42a transfers a SIP message received via the IP network 100 to the SIP message processing unit 42b, or transfers the SIP message transferred from the SIP message processing unit 42b to the IP network 100. Or send it to. For example, in order to request the system to register its own IPT, the communication processing unit 42a transmits a REGISTER message addressed to one of the IP addresses of the servers #A and #B.

  The SIP message processing unit 42b generates and interprets the SIP message. The operation follows the specifications of SIP UA (User Agent) described in RFC3261 and the like. The SIP message is generated when an event such as an input operation of the keypad unit 43 occurs, for example. The content of the SIP message is interpreted, for example, when the SIP message is received by the communication processing unit 42a, and the result is displayed on the display device 40 and notified to the user, for example.

  Further, the SIP message processing unit 42b describes, as a processing function according to this embodiment, identification information for identifying the cause of the registration request in the REGISTER extended area. That is, there are various causes for the IPT to request registration from the SIP server. Here, the following two are considered. That is, “initial registration” and “re-registration”.

The initial registration is a registration process as a procedure incorporated in an IPT activation routine or the like, and does not cause failure detection, and level 1 survivability is not directly related. On the other hand, re-registration is mainly caused by detection of a failure by IPT, and is one of the processes by level 1 survivability.
Tables 1 and 2 show examples of REGISTER.

Table 1 is an example of REGISTER notified to the server unit at the time of initial registration. Information “extended_register_first_register” is written in the extended area indicated as User-Agent: on the bottom line. This is identification information indicating that this is the first registration, and by interpreting this, the server unit can recognize that this REGISTER is not a registration request by level 1 survivability.

  Table 2 is an example of REGISTER notified to the server unit at the time of re-registration. Information “extended_register_fault_switchover” is written in the extended area in the bottom row. This is identification information indicating that this is re-registration. By interpreting this, the server unit can recognize that this REGISTER is a registration request based on level 1 survivability.

  FIG. 3 is a functional block diagram showing an embodiment of the SIP servers #A and #B shown in FIG. The SIP servers #A and #B include an interface unit 11, a display unit 12, an input / output unit 13, a database unit 14, and a main control unit 15. The interface unit 11 is connected to the IP network 100 and performs processing related to packet exchange. The display unit 12 provides a user interface together with the input / output unit 13 to construct a GUI (Graphical User Interface) environment. The database unit 14 is a storage device such as a hard disk drive, and stores a management table 14a.

  FIG. 4 is a diagram illustrating an example of the management table 14a. This table 14 is used for managing the association between the home server and the backup server for each IPT by associating the identifier of the home server with the identifier of the backup server for each domain name (DN) of the IPT. Is. Level 1 survivability is set based on the management table 14a. FIG. 4 shows that all IPTs having DNs 200 to 299 use server #A as a home server and server #B as a backup server. Conversely, IPTs having DNs 300 to 399 are shown to have server #B as the home server and server #A as the backup server.

  In the example of FIG. 4, a total of 200 IPTs are connected to the IP telephone system, but a setting is shown in which 100 IPTs are distributed and registered in two servers. By doing in this way, the merit of level 1 survivability that an IPT can be registered with a preset distribution without being biased toward a specific server can be obtained. Next, the operation in this embodiment will be described.

  First, a normal terminal registration procedure will be described with reference to FIG. The IPT 1 initialized by power on / off broadcasts an address acquisition request to the IP network 100 (1). Receiving this, the DHCP server 200 returns an IP address assigned to the IPT of the request source and the IP address of the SIP server of the connection destination (2).

  The IPT automatically logs in to the SIP server using a DN set in advance in its own terminal. Here, the IPT requests the SIP server notified from the DHCP server 200 for REGISTER, but the IP address of the SIP server notified from the DHCP server 200 is fixed. This is because the DHCP server 200 does not have the management table 14a.

  In other words, the IP addresses of the SIP servers notified by the DHCP server 200 to the IPT are always in the order of, for example, the SIP servers #A and #B. This means that the IPT first makes a connection request to the SIP server #A (3). If the connection fails due to a failure of the server #A, the IPT issues a connection request to the server #B.

  Consider a case where IPT # 1 is initialized under the above conditions. IPT # 1 uses the IP address received from the DHCP server and the IP address of the connected SIP server to issue a REGISTER request to the server #A by DN300. The server #A can recognize that the home server of the terminal of the DN 300 that has requested REGISTER is the server #B (see the management table 14a). However, in the conventional technique, the server #A cannot determine whether or not the REGISTER request is based on level 1 survivability. Therefore, server #A is forced to register IPT # 1 with its own server. If this is the case, IPT # 1 will continue to be connected to server #A, which is a backup server that is not the original connection destination. Next, an operation for solving this will be described.

  FIG. 5 is a diagram showing an example of a sequence in initial registration of IPT in this embodiment. In FIG. 5, the procedures (1) and (2) are the same as those in FIG. 1. In (3), IPT # 1 issues a REGISTER request to the SIP server #A. Here, in this REGISTER message, identification information (Table 1) indicating that the connection is not based on level 1 survivability is written.

The server #A that has received the REGISTER request recognizes that its own server is a backup server by referring to the management table 14a because the DN of the request source IPT # 1 is 300. Therefore, the server #A refers to the extended part of the REGISTER message and checks whether or not the registration is based on the level 1 survivability function. In this case, it is not registration by the level 1 survivability function. Therefore, server #A requests IPT # 1 to redirect and instructs IPT # 1 to send REGISTER again to server #B (4). Upon receiving this, IPT # 1 requests REGISTER from server #B. Server #B recognizes that its own server is the home server for IPT # 1, and registers IPT # 1 as DN300 in its own server.
If both the SIP server of the home server and the backup server are operating normally by the procedure as described above, the IPT that requested the registration is always registered in the home server.

  FIG. 6 is a diagram illustrating an example of an IPT re-registration sequence when the SIP server fails. FIG. 6 shows a state in which level 1 survivability is functioning. Assume that a failure occurs in the server #B after the IPT # 1 receives the server address notification through the procedures (1) and (2) in FIG.

  Then, IPT # 1 detects the failure of server #B by detecting, for example, KeepAlive disconnection, and requests REGISTER from server #A, which is a backup server. At that time, IPT # 1 adds identification information (Table 2) indicating that the connection is based on level 1 survivability to the REGISTER message.

  Server #A, which has received the REGISTER request from IPT # 1, recognizes that its own server is a backup server for IPT # 1, since DN of IPT # 1 is 300. Furthermore, the server #A refers to the received REGISTER identification information and checks whether or not the registration is based on level 1 survivability. In the case of FIG. 6, since the message clearly indicates that the registration is based on the level 1 survivability function, the server #A immediately registers IPT # 1. Thereafter, IPT # 1 is connected to server #A and starts communication.

  As described above, in this embodiment, an extension field is provided in REGISTER for requesting registration to the SIP server, and in this extension field, whether re-registration by level 1 survivability or not is specified. Added identification information. As a result, the SIP server that has received REGISTER can immediately issue an instruction (redirect request) to reconnect to the home server to the IPT that has connected to the backup server when level 1 survivability is not the cause. become able to. Therefore, the IPT is not registered in the backup server, but is connected to the home server that is the original connection destination.

  On the other hand, an IPT that has issued a REGISTER to the backup server due to the level 1 survivability action associated with the failure is registered in the backup server as it is. At that time, the backup server can obtain necessary information only by referring to the information in the extension field of the SIP message. Therefore, procedures such as a home server status check are not required, and advantages such as reduction in processing load and reduction in network load can be obtained.

Accordingly, it is possible to provide a communication system, a terminal registration method, and a server that can connect individual end points to a server that is an original connection partner.
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment.

  #A, #B ... SIP server, # 1, # 2 ... IP terminal (IPT), 100 ... IP network, 200 ... DHCP server, 60 ... LAN cable, 40 ... display unit, 41 ... IP interface unit, 42 ... control , 42a ... Communication processing unit, 42b ... SIP message processing unit, 43 ... Keypad unit, 44 ... Memory, 44a ... IP address (server #A), 44b ... IP address (server #B), 11 ... IP interface unit , 12 ... Display unit, 13 ... Input / output unit, 14 ... Database unit, 14a ... Management table, 15 ... Main control unit, 15a ... Identification unit, 15b ... Determination unit, 15c ... Registration processing unit

Claims (10)

Endpoints that can communicate,
A server that operates as a home server or a backup server for this endpoint,
The endpoint is
A transmission unit that transmits to the server a registration request with identification information for distinguishing whether the cause of the registration request is based on the occurrence of a failure;
The server
From the identification information given to the received registration request, a specifying unit for specifying whether the cause of the registration request is a failure,
When the local server is the home server for the endpoint of the received registration request, or when the local server is a backup server and the cause of the registration request is the occurrence of the failure, the endpoint of the endpoint A determination unit that determines that registration is permitted;
A communication system comprising: a registration processing unit for registering the end point in the own server when permitted by the determination unit; and instructing the end point to redirect the registration request when not permitted. And further comprising an address notification server for designating an address of a destination server of the registration request as the endpoint.
The communication system according to claim 1, wherein the transmission unit transmits the registration request to an address designated by the address notification server.   The communication system according to claim 1, wherein the server further includes a management database in which the home server and the backup server are associated with the endpoint. The server is a SIP (Session Initiation Protocol) server,
The communication system according to claim 1, wherein the registration request is REGISTER of SIP. In a terminal registration method of a communication system comprising an endpoint capable of communication and a server that operates as a home server or a backup server for the endpoint,
The endpoint sends a registration request with identification information for distinguishing whether the cause of the registration request is based on the occurrence of a failure to the server,
The server specifies whether or not the cause of the registration request is a failure from the identification information given to the received registration request,
If the server is a home server for the endpoint from which the received registration request is sent, or if the server is a backup server and the cause of the registration request is the occurrence of the failure, the server Allow endpoints to register,
If the registration of the endpoint is permitted, the server registers the endpoint with the server, and if not permitted, the server instructs the endpoint to redirect the registration request.   6. The terminal registration method according to claim 5, wherein the registration request is transmitted from the endpoint to an address designated by an address notification server that designates an address of a destination server of the registration request.   6. The terminal registration method according to claim 5, wherein permission for registration of the endpoint is determined based on a management database in which the home server and the backup server are associated with the endpoint. The server is a SIP (Session Initiation Protocol) server,
6. The terminal registration method according to claim 5, wherein the registration request transmitted from the endpoint is transmitted with the identification information added to REGISTER in SIP. In a server that accommodates endpoints that can communicate and operates as a home server or backup server,
From the identification information given to the registration request received from the endpoint, a specifying unit that specifies whether the cause of the registration request is a failure,
When the local server is the home server for the endpoint of the received registration request, or when the local server is a backup server and the cause of the registration request is the occurrence of the failure, the endpoint of the endpoint A determination unit that determines that registration is permitted;
A server comprising: a registration processing unit that registers the end point with its own server when permitted by the determination unit; and that instructs the end point to redirect the registration request when not permitted.   The server according to claim 9, further comprising a management database in which the home server and the backup server are associated with the end point.

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