Apparatus and method for synchronizing databases in distributed communication systems

Apparatus and method for synchronizing databases in distributed communication systems utilizing a server for a preferably private communication system having a number of communications installations connected to one another via a network, the server including a central database for centrally storing data for the individual communications installations and a central synchronization device which synchronizes the data between the central database and the individual communications installations.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a schematic illustration of a server 1 in a preferably private communication system or communication network in accordance with the principles of the present invention. The server 1 is connected to one or more communications installations 2 , 3 via a network. The communications installations 2 , 3 each have a local database 21 , 31 for storing data specific to the communications installations (hereinafter referred to as first data). In this context, the connecting lines with arrows indicate the direction in which messages or data are interchanged between the communications installations 2 , 3 themselves or between the server 1 and the communications installations 2 , 3 . In the present exemplary embodiment, the network is an IP-oriented (Internet Protocol) network, in which data is transmitted using a transmission protocol based on the IP protocol. The central unit of the server 1 is formed by a central database 11 , which stores a depiction (copy) of the individual local databases 21 , 31 of the respective communications installations 2 , 3 or parts of these local databases 21 , 31 . A central synchronization device 12 of the server 1 monitors the central database 11 for any change to first data, required for operating a communications installation 2 , 3 , for example, stored in the central database 11 . If first data affecting one or more communications installations 2 , 3 has been changed in the central database 11 , then the changed first data is transmitted by the central sychronization device 12 to the appropriate communications installation(s) 2 , 3 via the network. The communications installations 2 , 3 receive the changed data via a local updating device 23 , 33 which is arranged in the respective communications installation 2 , 3 and is used to update the first data stored in the respective local database 21 , 31 . The first data can be centrally administered and managed using a central administration device 13 . A central checking device 14 of the server 1 checks whether changed first data affecting a communications installation 2 , 3 result in a change to first data in other communications installations 2 , 3 (e.g., when a call number plan is changed) and automatically updates these first data in the central database 11 . The first data changed in this manner are then transmitted to the appropriate other communications installations 2 , 3 via the network, as a result of which the first data stored in the local databases 21 , 31 of the appropriate communications installations 2 , 3 are updated. If data in a local database 21 , 31 in one of the communications installations 2 , 3 is changed (e.g., an entry for a shortcode dialing destination), then this entry also needs to be updated appropriately in the central database 11 . For this purpose, the communications installations 2 , 3 contain a respective local synchronization device 22 , 32 monitoring the appropriate local database 21 , 31 for changes. In cases in which first data in a local database 21 , 31 are changed, the local synchronization device 22 , 32 transmits the changed first data to the server 1 via the network. The changed first data is received by a central updating device 15 and is entered into the central database 11 . In addition, the communications installations 2 , 3 can use a respective local access device 24 , 34 to access second data, stored in a central database 11 , which is not available in the respective local databases 21 , 31 . FIG. 2 shows one preferred embodiment of a distributed communication system having three communications installations 2 , 3 , 4 and a central server 1 . Connected to the communications installations 2 , 3 , 4 are a respective number of communication terminals (e.g., telephones). In the present exemplary embodiment, the communications installations 2 , 3 , 4 are networked via a local area network (LAN) in which data are transmitted using the IP protocol. Alternatively, the communications installations 2 , 3 , 4 can also be networked using a tunneling mechanism via circuit-switched networks (e.g., an ISDN-oriented communication network). In this case, the messages of a networking protocol specific to the communications installation are, by way of example, packaged into appropriate messages of the transmission protocol (e.g., IP, ISDN) and are sent via the network. In the present exemplary embodiment, the communications installations 2 , 3 , 4 are connected to one another via an Ethernet LAN and can interchange signaling and voice data via this Ethernet LAN. The individual communications installations 2 , 3 , 4 are connected to the LAN via a respective LAN interface implemented in each of the communications installations 2 , 3 , 4 . Each communications installation 2 , 3 , 4 has a local database 21 , 31 , 41 for storing first data specific to the communications ion. Incorporated in the central server 1 is an all-embracing central database 11 containing a depiction of all the first data 21 ′, 31 ′, 41 ′ or of at least some of the first data of all the communications installations 2 , 3 , 4 arranged in the communications system. Between the server 1 and the communications installations 2 , 3 , 4 , there is a network connection for bidirectional data interchange. A central synchronization device 12 of the server 1 and local synchronization devices 22 , 32 , 42 of the communications installations 2 , 3 , 4 ensure that, in the event of a change to first data in the central database 11 or in one of the local databases 21 , 31 , 41 , the corresponding first data in the respective communications installations 2 , 3 , 4 or in the server 1 are automatically updated. The central database 11 , combined in this way, represents a depiction of the whole communication system, formed from a number of communications installations 2 , 3 , 4 , in the representation of a single system (Single System Image). The central database 11 can be viewed, altered and/or configured by an appropriately designed central administration device 13 . In addition, a central checking device 14 of the server 1 is used to provide a consistency check, so that, by way of example, it is not possible to allocate call numbers twice within the communications system. Besides the first data of the individual communications installations 2 , 3 , 4 , the central database 11 also contains additional information (hereinafter referred to as second data) relating to the communications installations 2 , 3 , 4 . The second data contains information such as the address of a communications installation 2 , 3 , 4 in the network, this additional information being significant to the communication network. From the outside and from the administrative point of view, this possibly worldwide system interconnection acts like a single installation and can also be administered like such an installation. The central database 11 is likewise accessed for cross operations between the communications installations 2 , 3 , 4 . By way of example, when a first subscriber A on the communications installation 2 calls a second subscriber B on the communications installation 3 , the server 1 can provide all the necessary information (second data), such as name and address, relating to the desired second subscriber B. If the communications installation 2 does not know the location of the desired second subscriber B, then this can be requested via the central database 11 using the local access device 24 , 34 , 44 . In this way, it is not absolutely necessary for each communications installation 2 , 3 , 4 to have available all the locations of the subscribers in the whole communication system. Similarly, FIG. 2 shows the central updating device 15 , explained with reference to FIG. 1 , and the respective local updating devices 23 , 33 , 43 . Joint central administration can also be carried out and used for individual systems which are at a great physical distance from one another (e.g., in other towns and countries) and are, for example, connected to one another via an IP network (Internet). The server 1 can also provide additional applications, for example, to extend the functionality of the communications installations 2 , 3 , 4 , such as service features and CTI applications (Computer Telephony Integration). To this end, the server 1 holds an operating system (e.g., Windows NT) holding the individual software components. Although the present invention has been described with reference to specific embodiments, those of skill in the art will recognize that changes may be made thereto without departing from the spirit and scope of the invention as set forth in the hereafter appended claims.