KR20090102140A - Location server, communication system comprising the location server and communication method using the location server - Google Patents

Abstract

PURPOSE: A location server, a communication system comprising the same and a communication method thereof are provided to increase the efficiency of the communication system without the interworking with an external circuit network for a newly added switching center. CONSTITUTION: A communication system includes an originating-side switching center(30) and a location server(20). The originating-side switching center processes the reception of an outgoing call. The location server stores information about a switching center in which the destination number of the outgoing call is stored, and then provides information about destination-side switching center to the originating-side switching center in response to the request of the originating-side switching center. The originating-side switching center transmits the outgoing call to a subscriber terminal corresponding to the destination number when the originating-side switching center information is the same as the destination-side switching center information.

Description

LOCATION SERVER, COMMUNICATION SYSTEM COMPRISING THE LOCATION SERVER AND COMMUNICATION METHOD USING THE LOCATION SERVER}

 The present invention relates to a communication system and a communication method in a remote call forwarding (RCF) number porting based network provided by an existing circuit-switched network as well as a voice over internet protocol (hereinafter referred to as 'VoIP'). It can be used for communication based system by ACQ (All Call Query).

In general, a VoIP service digitizes an analog voice signal, compresses the digitized signal, and then performs signal processing using a signaling protocol such as H.323, Session Initiation Protocol (SIP), or media gateway control protocol (MGCP). After passing through the RTP packet, the IP is a telephone service that allows voice calls by transmitting in a packet form over a TCP / IP (Transmission Control Protocol / Internet Protocol) network such as the Internet or a corporate intranet. Unlike public switched telephone network (PSTN), which is a circuit-switched telephone that can use the network as it is and that the circuit must be connected exclusively for the duration of the call, multiple calls share the same network. It has the advantage of being available.

In addition, VoIP service is an alternative to PSTN because it can reduce the communication cost because it uses a data network and voice communication network, and recently, with the spread and activation of broadband Internet, Internet call center, Internet unified messaging system (UMS), The service is applied to various fields such as corporate telephone network.

As the number of VoIP service subscribers increases, there is a need to establish a soft switch (hereinafter referred to as SSW), which is a large number of exchanges in the coverage area. At this time, VoIP service subscribers should be subdivided into regions to establish a plurality of SSWs. Then, the SSW deployment for each region for the small number of subscribers scattered nationwide requires a huge capital expenditure (CAPEX).

In addition, due to the increase in the number of VoIP service subscribers, routing between subscribers becomes complicated, and a public switched telephone network (hereinafter, referred to as a 'PSTN') has difficulty in moving a subscriber to an IP network. Specifically, the increase in the number of VoIP service subscribers expands the VoIP communication system, and the number of interconnections between the VoIP communication systems increases in proportion to the number of the extended VoIP communication systems. In addition, the current VoIP network structure has a function of accepting VoIP subscribers and interworking with other SSW and external networks. Then, when the SSW is added, the added SSW should have a function capable of interworking with an existing SSW and also interworking with an external network. This results in an inefficient relay circuit configuration. In addition, due to the unclear system of using prefixes, it is not easy to separate subscribers by region, and when additional nodes are expanded, subscribers of the same station number may be mixed in different systems, which makes routing difficult.

In addition, in order to provide domestic Local VoIP Number Portability (LVNP) or Local Number Portability (LNP), a routing method follows a remote call forwarding (RCF) method. Specifically, according to the RCF method, the routing is received by the existing network that accepts the existing circuit subscriber (number subscriber before the number transfer), and then the call to the last number provider or subscriber after the number transfer through a call forwarding procedure. In this process, it is unavoidable to receive the call via the donor network. In other words, IP-to-circuit conversion is necessary for subscribers whose number is transferred to the IP network via the circuit network, and reconversion to Circuit-IP is necessary when the destination network is the IP network. Therefore, despite the calls within the IP network, multimedia signal transmission is impossible in the process of passing the circuit, and thus a problem that cannot provide multimedia services aimed at the next-generation network occurs.

In addition, in the process of the first incoming call to the number transfer provider, the IP to IP call also goes through the circuit network primary service provider. In this case, a problem arises in that some connection fee must be paid due to the use of circuit network resources.

A communication system according to an aspect of the present invention stores an originating exchange station that receives and processes an outgoing call, and information about a destination exchange or wholesaler that has received a destination number of the outgoing call, and in response to a request of the originating exchange, the destination exchange station information. And a location server providing the calling exchange to the calling exchange, wherein the calling exchange transmits the calling call to the subscriber station corresponding to the called number when the calling exchange information and the called exchange information are identical. In other cases, the destination exchange station information is added to the originating call and relayed. And when the originating exchange relays the originating call, further comprising a relay exchange receiving the originating call from the originating exchange, wherein the relay exchange uses the destination exchange information to connect the destination exchange to its own station. If the destination exchange station is an exchange station connected to its own station, the originating call is relayed to the destination exchange station. If the destination exchange information is information of an external network, the relay exchange relays the originating call to the external network. When the relay switching center receives an incoming call from an external network, it requests the destination server information of the incoming call to the location server and relays the destination switching station information received from the location server to the incoming call. The external network is at least one of an external VoIP network, an ITSP network and a circuit network. In a communication system according to an aspect of the present invention, if the destination exchange station is not an exchange station connected to the relay exchange station, the relay exchange station transmits the outgoing call to which the destination exchange station information is added to another relay station to which the destination exchange station is connected. Relay to the exchange. And when there are a plurality of location servers, the originating switching center requests the corresponding location server from among the plurality of location servers according to the called number to request the switching station information of the called number. Further, when the called number is the telephone number before the number shift, the location server changes the called number to the subscriber terminal number after the moved number of the called number, and transmits the called switching center information and the changed called number to the calling exchange station. To pass. The called number may include a domain.

In a communication method for receiving an outgoing call and receiving the outgoing call to a subscriber station of a called number of the outgoing call according to another aspect of the present invention, receiving a request for incoming exchange station information accommodated by the subscriber station from an originating exchange station Retrieving switching center information and providing the retrieved terminating exchange information to the calling switching center. The step of retrieving the destination switching center information may include changing the called number to a number of a subscriber station corresponding to the telephone number before the number movement, when the called number is a telephone number before the number movement and the called party to the calling exchange. Conveying switching center information and the changed called number.

A location server of a communication system according to another aspect of the present invention, comprising: an operation management unit for receiving a request for information about an incoming exchange station received by a terminating subscriber station from an originating exchange station, and providing a response to the request to the originating exchange station; A query processing unit which stores exchange station information accommodated by the subscriber station for each called party number of the subscriber station, retrieves information on the destination exchange station accommodated by the receiver subscriber station according to the request, and provides the retrieved destination exchange station information as the response; It includes. The query processing unit stores the subscriber terminal number after the number shift for each telephone number before the number shift, and when the called number is the telephone number before the number shift, changes the called number to the subscriber terminal number after the number shift; The changed destination number is provided in the response along with the retrieved destination exchange information. When a plurality of request messages are received, the query processing unit generates a processor for performing a response to each of the plurality of request messages and processes a query for each call of the plurality of request messages. The query processing unit has a redundancy structure divided into an active area for processing a query for each call of the request message and a standby area for performing the same query processing instead of the active area if the active area does not operate.

As such, the communication system and the communication method according to the embodiment of the present invention include a higher level switching center and a location server, and solve a problem that may occur due to an increase in subscribers.

As subscribers increase, so does the number of subscribers that the bureau must accept. However, the number of subscribers that an exchange can accept is limited, so a new exchange must be established. This not only increases the number of interconnection points between switching stations, but also encounters limitations on acceptable subscribers and subscriber numbers, which complicates the network so that it is impossible to identify which switching station or domain belongs to which subscriber. Since the present invention includes an upper layer switching station, the number of connection points between the switching stations can be reduced. That is, a newly installed exchange can connect with other former exchanges if it connects with a higher-level exchange. This solves the problem of interconnection with all previous exchanges. In this way, since the exchange is divided into upper and lower layers for routing processing, relay call processing can be separated into the upper level switching center. Therefore, newly added exchanges do not need to interwork with external circuit networks using media gates, thereby increasing the efficiency of the communication system.

In addition, the communication system and the communication method according to an embodiment of the present invention can know the routing information of the subscriber from the location server that provides the location information of the exchange station accommodated by the subscriber, so that the subscribers of the same station number to different systems when additional switching stations You can overcome the mix. That is, since the location information of all the subscribers is stored in the location server, all the exchange stations interworking with the location server can accurately know the final location information of the called party through the query with the location server.

In addition, the communication system and the communication method according to an embodiment of the present invention, in the case of subscribers subscribed by number movement, store the existing number and the transferred number together before moving the number in the location server, and answer the query of the switching center. Therefore, it provides an environment where the exchange can accommodate the subscriber regardless of the subscriber's existing station number.

In addition, there is no need for primary routing to the called party for incoming calls to number ported subscribers. That is, since the first source switching center attempts to route directly to the last destination switching station and does not pass through the primary provider (Donor provider), the access fee for the primary routing to the original destination does not occur. Therefore, the cost can be reduced.

In addition, the present invention is to directly route from the originating switching center to the destination switching station according to the location server response, overcoming the release of the media session (media session) occurring when passing through the circuit-based network of the primary carrier network, MM (MultiMedia) Overcome limitations in service delivery.

1 is a diagram showing the basic unit configuration of a communication system according to an embodiment of the present invention.

2 is a diagram briefly showing information transmitted and received between the SSW 30 and the LS 20.

3 is a diagram illustrating an extended case of a communication system according to an exemplary embodiment of the present invention.

4 is a diagram illustrating another example in which a communication system according to an embodiment of the present invention is expanded.

5 is a diagram illustrating another example in which a communication system is extended according to an exemplary embodiment of the present invention.

6 is a diagram illustrating an intra call processing method in the same switching center in a communication system according to an exemplary embodiment of the present invention.

FIG. 7 is a diagram illustrating a method in which an incoming call is routed to an internal relay call to reach another switching station in a communication system according to an exemplary embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In other words, the scope of the present invention can be equally applied to the location-based routing information at the originating exchange end of the circuit-based network as well as to the routing based on the received routing information.

 In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Hereinafter, with reference to the contents shown in the drawings will be described in detail an embodiment of the present invention. A communication system and a communication method according to an embodiment of the present invention will be described by taking a VoIP network as an example. However, the present invention is not limited thereto.

1 is a diagram showing the basic unit configuration of a communication system according to an embodiment of the present invention.

A communication system according to an embodiment of the present invention includes a subscription system 10, a location server (hereinafter referred to as "LS") 20, and an exchange system such as SSW 30. Hereinafter, an embodiment of the present invention will be described including a VoIP network. However, the present invention is not limited thereto and may be equally applied to a circuit-based exchange system, that is, a circuit exchanger.

The provisioning server 10 has basic information for storing and managing information on subscribers and services of the VoIP service, and determining whether the subscribers subscribe to the service and whether the user subscribes to the service. The subscription system 10 is interlocked with the LS 20 to transmit data of the subscriber's location (for example, location information of the subscriber, location information, call right information, supplementary service subscription information, final subscriber acceptance information, etc.) to the LS 20. Perform the process.

At this time, the subscription system 10 moves the number in real time or periodically through interworking with the number portability DB of the NPDB (Number Portability Database) which accommodates the entire number portability database (hereinafter referred to as 'DB'). Receive information. Accordingly, the LS 20 can receive all the information of the domestic number porting from the subscription system 10.

The subscription system 10 manages the station numbers, and automatically transmits registration / subscription data for new subscribers to the LS 20 when subscribers of a particular station number are provisioned. At this time, the registration / subscription data includes whether the subscriber's number is moved, the telephone number before the subscriber's number movement, the mediation number after the number movement, and the accommodating service provider and exchange system information. It is used as. Then, the LS 20 may include the location information of the subscriber in detail, and the location information may be used as the routing information in the routing process between the switching centers.

The SSW 30, as the switching center, processes outgoing call requests from subscriber stations and controls call processing of media gateways (not shown) that serve as bridges between circuit networks and packet networks. Although not shown, the circuit exchanger may also perform the same function as the SSW 30. The media gateway converts PSTN-based media traffic into IP-based media traffic between the PSTN and the IP network. If there is a call request for the called number, the SSW 30 requests the LS 20 for inquiry of the final location information according to whether or not there is a number porting and moving of the called number, and the location information of the requested called number If it matches with, it judges that it is a local subscriber and makes a call to the terminal of the called number. If the location information does not match the local switching center, the SSW 30 considers the subscriber of the other switching center to add the switching center location information and the routing / number information to the received call request and relays the call. The SSW 30 interworks with subscriber signals of the subscriber station and the circuit network and VoIP subscriber protocols such as H.323 / MGCP (media gateway control protocol) or SIP (session initiation protocol) of the packet network, and makes a call request or an incoming call. To control.

LS 20 provides location information of the VoIP service subscriber. In detail, the LS 20 interworkes with the SSW 30 and inquires of the location information of the subscriber station at the request of the SSW 30 and transmits the location information of the subscriber station to the SSW 30. The LS 20 transmits the final destination information by requesting the subscription system 10 the data necessary for the response from the query with the SSW 30 and responding to the SSW 30 for each stored and incoming call. The LS 20 is a query processing server unit (QPSU) that processes a query of an element management server unit (EMSU) 21 and an SSW 30 that manages operation of a component of the LS 20. (22). The operation management unit 21 receives a request for switching station information accommodated by the subscriber station from the SSW 30, provides a response to the request to the SSW 30, and includes an interface for receiving a request and providing a response. Perform administrative functions.

The query processing unit 22 searches for information on the switching center accommodated by the subscriber station at the request of the SSW 30, and provides the retrieved destination switching center information as a response. The query processing unit 22 has a redundant structure for system stability. The redundant structure refers to a structure in which the standby area is configured to operate when the active area of the query processing unit does not operate. If there are a number of lower switching systems (SSWs) interworking with and managed with the LS 20, and another request message is received from another switching system or from the same switching system while the request message is requested from any switching system, The processor 22 generates a processor for performing a corresponding response to each of the plurality of requests, and then performs a query for the corresponding transaction for each requested call.

The query processor 22 includes a memory database (not shown) for quick query processing. The memory database may store location information in a table. At this time, the location information is consistent with the information received from the subscription system and NPDB. Specifically, the location information is data relating to the mediation number of the subscriber station for responding to the query, the exchange station information accepted by the subscriber station, and the telephone number before the number transfer. The LS 20 receives and stores data necessary for query processing from the subscription system 10. In this case, the above-mentioned mediation number is a temporary and control number for call forwarding routing given by the called party that matches the number of the subscriber before the number transfer in the RCF number movement process, and identifies the subscriber station of the destination switching center during call processing. This number is referred to as a subscriber number below. The LS 20 stores the telephone number before the number transfer and the subscriber number and the switching center information of the subscriber station after the movement together. The memory database stores the tabled data. If the called number requested by the SSW 30 is the telephone number before the number transfer, the LS 20 changes the called number to the subscriber number and transfers it to the SSW 30 together with the switched station information. The routing procedure then consists of the called number changed to the subscriber number. The interworking interface between the LS 20 and the SSW 30 is provided with a Diameter protocol, and a SIP Rediection Method is used. The LS 20 receives and stores data of a new subscriber from the subscription system 10 in association with the subscription system 10.

Hereinafter, a method for SSW inquiring subscriber location information to LS in a VoIP communication system will be described with reference to FIG. 2.

2 is a diagram briefly showing information transmitted and received between the SSW 30 and the LS 20.

SSW 30 requests the routing information for the subscriber station of the called number to the LS (20) (S10). The called number may be a local telephone number, a 070 Internet telephone number, a subscriber number with another telephone numbering system, or a telephone number before the number transfer. At this time, the exchange information and the destination number of the SSW 30 requesting routing information are transmitted together.

The LS 20 provides the routing information in response according to the received query request exchange information. The routing information is location information for accommodating the subscriber station of the called number and is switching center information. Specifically, the LS 20 transmits to the SSW 30 the exchange station information accommodated by the subscriber station of the called number as a response to the query (S20). The LS 20 transfers the subscriber number together to the SSW 30 after the number shift, if the telephone number before the number shift is received with the request as the called number. Then, the subscriber number is handled along with the call relayed from the SSW 30 to which the originating call is received to another switching center. At this time, the switching center information, which is the location information, is added to the subscriber number to process the call. If the switching center information received from the LS 20 is the own station, the SSW 30 forwards the call sent to the subscriber station according to the subscriber number. A detailed communication system and communication method will be described later with reference to FIGS. 3 to 7.

3 is a diagram illustrating a case where an VoIP communication system according to an embodiment of the present invention is expanded.

The VoIP communication system shown in FIG. 1 includes one LS 20, and the amount of information and traffic for a subscriber station that the LS 20 can accommodate is limited. Therefore, as the subscriber station increases, it is necessary to include additional LS to accommodate information about the increased subscriber station and to distribute the increased traffic.

As shown in Fig. 3, the VoIP communication system includes two LS1 (21) and LS2 (22), each of the LS1 (21) and LS2 (22) has a predetermined station number (A, B, C, D) ) Or accept information about domains (E, F). Station numbers (A, B, C, D) can be classified by region or by prefix. The prefix is information included in the called number, and means the area code included in the telephone number before the number movement or the front digit number of the mobile telephone by the carrier. The rules for separating and accepting domains can be changed according to configuration. In the LS 20 of FIG. 1, all of the A, B, C and D subscriber stations and the domain are accommodated. However, as the number of subscribers increases, each of the LS1 21 and LS2 22 separately accommodates the A and B station subscriber stations and the E domain, and the C and D station subscriber stations and the F domain. Then, each of LS1 (21) and LS2 (22) is linked to the subscription system 10, LS1 (21) stores the information about the A and B station number subscriber terminal and E domain, LS2 (22) is C and Stores information about the D station subscriber station and the F domain. The SSW 31 may query the subscriber station or the domain location information with the appropriate LS among the LS1 21 and the LS2 22 according to the station number during the call processing. The subscription system 10 allows the subscriber terminal or domain data to be automatically input to the appropriate LS of the LS1 21 and the LS2 22 when the subscriber station or the domain of a particular station number is provisioned. Hereinafter, the subscriber station also includes a domain.

4 is a diagram illustrating another example in which a VoIP communication system according to an embodiment of the present invention is expanded.

As shown in FIG. 4, the VoIP communication system includes three SSW1 32, SSW2 33, and SSW3 34. Each of SSW1 32, SSW2 33 and SSW3 34 may query the subscriber terminal location information to LS3 23 during call processing. The LS3 23 performs the same function as described above and is connected to the subscription system 10.

The VoIP communication system of the present invention includes a plurality of SSWs layered. SSW1 32 and SSW2 33 are switching centers serving as subscriber terminal receiving stations. Each of SSW1 32 and SSW2 33 is connected to a subscriber station and interworked with a predetermined protocol (MGCP, SIP). As an exchange station serving as a subscriber station accommodating station, two SSW1 32 and SSW2 33 are set as an example, and the present invention is not limited thereto. That is, the query to the LS may be performed regardless of the hierarchy (subscriber receiving station and relay station) or the mediaization (circuit and switching network), so that routing may proceed. SSW3 34 is a relay station that performs a relay role. SSW3 34 acts as a relay station between SSW1 32 and SSW2 33. SSW3 (34) is connected to each of SSW1 (32) and SSW2 (33). In a packet network, a circuit network such as session initiation protocol-telephone (SIP-T) or H.323, as well as BICC (Bearer Independent Call Control), Can be linked as a No.7 relay signal.

The SSW3 34 serves as a relay station between any one of the SSW1 32 and the SSW2 33 and the existing circuit networks PSTN and PLMN. The SSW3 34 is connected to the existing circuit network 1 through a media gateway (hereinafter referred to as MG) and a signaling gateway (SG). The SSW3 34 may interwork with the media gateway MG and the MGCP, and interwork with the signaling gateway SG through the Sigtran protocol. The SSW3 34 is connected to each of an Internet telephone service provider network (ITSP) network 2 and an external VoIP network 3, and interworked with H.323 or SIP. SSW3 (34) serves as a relay between each of the external VoIP network (3) and ITSP network (2) and SSW which is a corresponding subscriber station among SSW1, 2 (32, 33) of the VoIP system to which the own station belongs. In addition, it may serve as a relay between the circuit network 1, the external VoIP network 3 and the ITSP network (2). Hereinafter, when it is necessary to distinguish between the subscriber station receiving station and the relay station, the switching center SSW serving as the subscriber terminal receiving station is referred to as "C5 SSW", and the switching station SSW serving as the relay station is referred to as "C4 SSW". The network of a VoIP communication system according to an embodiment of the present invention is a C4 SSW, a node for C5 SSW to accept a VoIP subscriber station and a node for interfacing with a plurality of C5 SSWs or circuits, external VoIP networks and ITSP networks. It includes a relay network.

5 is a diagram illustrating still another example in which a VoIP communication system according to an embodiment of the present invention is expanded.

As shown in FIG. 5, the VoIP communication system includes three C5 SSW1 32, C5 SSW2 33, C4 SSW3 34, LS1 21 and LS2 22. Each of the C5 SSW1 32, the C5 SSW2 33, and the C4 SSW3 34 may query the subscriber station location information with the appropriate LS among the two LS1 21 and LS2 22 during call processing according to the station number. The rest of the description is the same as described above with reference to FIG. 3.

So far, the configuration and structure of the VoIP communication system have been described. In addition, it can be extended to other forms. In the VoIP communication system of the above-described embodiment, a call that includes routing information to the SSW in the network is regarded as already inquired, and the routing process is performed immediately according to the routing information without querying the LS. Specifically, in FIG. 4, when the C5 SSW1 32 is a subscriber station whose called number is accommodated in the C5 SSW2 33 after receiving the query, routing information is acquired from the LS2 22. Thereafter, the C4 SSW3 34 and the C5 SSW2 33 may perform call processing without querying routing information to the LS1 21 and the LS2 22. Hereinafter, a call processing method in a network of a VoIP communication system will be described with reference to FIGS. 6 and 7.

6 is a diagram illustrating an intra call processing method within the same exchange in a VoIP communication system according to an embodiment of the present invention.

As shown in Fig. 6, the SSW 330 is an exchange station, and the exchange station information is set to " 100 ".

First, subscriber station A requests a call targeted at subscriber station B (S101). At this time, the subscriber number of subscriber station A is set to "200-1000", and the subscriber number of subscriber station B is set to "300-1000". This is an example for convenience of description. When the SSW 330 detects a call origination, the SSW 330 requests location information of the called number "300-1000" from the LS 210 (S102). The LS 210 stores and stores the subscriber number and the exchange information to which the subscriber number belongs. The LS 210 responds to the SSW 330 with the switching center information " 100 " to which the called number " 300-1000 " The SSW 330 assumes that the switching center information " 100 " coincides with the local switching center information, so that the subscriber station of the called number is accepted in the local SSW 330 and performs the incoming call processing procedure (S104). The relay call is processed from another switching station, so that the SSW 330 is processed in the same manner even if it is the final switching station.

Next, a case in which an incoming call is routed to an internal relay call in a VoIP communication system according to an embodiment of the present invention will be described with respect to another switching center.

FIG. 7 is a diagram illustrating a method in which an incoming call is routed to an internal relay call to reach another switching station in a VoIP communication system according to an exemplary embodiment of the present invention. An incoming call is routed to an internal relay call and is received by another switching center. The incoming call is classified into an originating call occurring in a VoIP communication system network and an incoming call coming from an external network.

First, the case where the originating call is routed to the internal relay call is received at another switching station.

As shown in FIG. 7, the VoIP communication system service network includes a C4 SSW1 341, a C4 SSW 342, a C5 SSW1 351, a C5 SSW2 352, and an LS 220. The LS 220 stores, as a table, switching station information of each of the C4 SSW1 341, the C4 SSW 342, the C5 SSW1 351, and the C5 SSW2 352, and the subscriber station number accommodated in each switching station. The exchange station information of the C4 SSW1 341, the C4 SSW2 342, the C5 SSW1 351, and the C5 SSW2 352 are "200", "300", "100", and "400", respectively.

The subscriber station B has a number of "300-1000" and the subscriber station C has a number of "300-2000". This is only an example set for convenience of description. &Quot; 300-1000 " is a subscriber number stored in C5 SSW1 351 having switching center information " 100 ", and " 300-2000 " is a subscriber number stored in switching center information " 400 ". The subscriber station B makes a call request using the subscriber number of the subscriber station C as the called number (S201). C5 SSW1 351 requests the LS 220 for location information on “300-2000” according to the call request (S202). The LS 220 responds with the location information " 400 " of " 300-2000 " to the C5 SSW1 351 (S203). Location information " 400 " is switching center information, which is routing information. At this time, the call can be made to the destination terminal of the telephone number before the number transfer, not the subscriber number "300-2000" of C. Specifically, when the terminal B, which previously used the number "02-2500-1234", becomes a subscriber terminal using the VoIP communication system network through number movement, the terminal number "02-2500-1234" from any terminal. The call request can be sent using the number. Then, the C5 SSW1 351 accommodated by any terminal queries the LS 220 according to the prefix "02" of the previous number, and the LS 220 recognizes that the previous number is the called number for the subscriber station B. After the switching center information and the number shift, the subscriber station B's subscriber number is returned to the C5 SSW1 351 together. Since the requested query result value is not the same as the local exchange information "100", the C5 SSW1 351 determines that the subscriber station is accommodated in the other switching center C5 SSW2 and performs a relay call routing procedure based on the routing information. Thereafter, the C5 SSW1 351 adds the routing information "400" to the subscriber number to route the call "400-300-2000" to the C4 SSW1 341 (S204). The C4 SSW1 341 performs the relay call routing procedure to the C4 SSW2 342 which is the relay station of the switching center "400" according to the routing information (S205). Then, the call is introduced to the C4 SSW2 342, and the C4 SSW2 342 performs the relay call routing procedure to the C5 SSW2 352 according to the routing information "400" (S206). C5 SSW2 352, because the routing information is consistent with its switching center information, it is determined as the subscriber station of the own station, and the call to the subscriber station C according to the called number "300-2000" as the incoming procedure (S207).

As such, the VoIP communication system according to an embodiment of the present invention includes routing information and transmits the routing information to the final switched office. Switching station information " 400 " is added as routing information before the telephone number " 300-2000 " of subscriber station C, so that each of the switching centers 200-400 does not query the routing information to the LS 220 when routing to the next hop. You don't have to. Even in the case of an intra call, if a call request is made to the phone number before the number movement, the call may be processed in the same manner.

Next, with reference to FIG. 7, the case where an incoming call is routed to an internal relay call is received at another switching center. In a VoIP communication system, when an incoming call is received from an external network, the switching station-SSW-, which receives the first call, queries the routing information to the LS. In this case, the external network may include an external VoIP network, an ITSP network, and a circuit network.

As shown in FIG. 6, when a call is received from the external network to the C4 SSW2 342 (S301), the C4 SSW2 342 requests the location information of “300-2000” to the LS 220 (S302). . At this time, the external network includes a general interrogator (EX), an Internet private automatic branch exchange (hereinafter referred to as "IP-PBX"), and SSW of another VoIP communication system network. The LS 220 responds with the location information " 400 " of " 300-2000 " to the C4 SSW2 342 (S303). At this time, the location information "400" becomes routing information. Then, the C4 SSW2 342 adds the location information "400" to "300-2000", and performs the relay call routing procedure to the C5 SSW2 352 according to the routing information "400" (S204). C5 SSW2 352, because the routing information is consistent with its switching center information, it is determined as the subscriber station of the own station, and forwards the call to subscriber station C according to the called number "300-2000" as the incoming procedure (S205).

As such, the SSW for querying the LS 220 is the SSW of the call origination location in case of a call-generated call generated by the subscriber station, and the call price in the case of a call-incoming call incoming from an external network. It is an incoming SSW. A query is made to the LS 220 at the first point where a call is made and received. In the same VoIP communication system network, the SSW after the initial point of call origination and arrival does not query LS 220. For this purpose, the LS inquiry setting function is turned off at the incoming route after the initial point.

Hereinafter, with reference to Table 1 it will be described whether the SSW performs the LS query according to the type of call.

In case of an originating call, SSW queries LS only when the prefix condition is met. The prefix is a value included in the called number.For example, if the prefix is an area code (meaning the prefix condition "ON"), a query is required with LS, and if it is a mobile communication number (meaning the prefix condition "OFF") LS No query is required.

In the case of an incoming call, the SSW queries LS only when the incoming route condition is an AND condition of the prefix condition. The incoming route condition is a condition that sets whether or not to perform a query on a route that requires a query to the LS of the incoming call path. If the incoming route condition is OFF, no queries will be performed for all incoming calls to the route. If the incoming route condition is ON, the LS query is performed for a call whose prefix condition is ON. For example, in an internal trunking system such as an external network (PSTN, ITSP) or IP-PBX and CENTREX, a route formed with either C4 SSW1 341 or C4 SSW2 342 is an incoming route condition. Can be set to "ON". If the prefix condition of the incoming call as the incoming route condition is "ON", the corresponding SSW of the C4 SSW1 341 and the C4 SSW2 342 queries the incoming call to the LS 210. This is because the incoming call to the route whose incoming route condition is "ON" may be a call that can be received by the VoIP subscriber station. In this case, the VoIP subscriber station means a subscriber station accommodated in the C5 SSW1 351 and the C5 SSW2 352.

In the case where the incoming route condition is "OFF" and the prefix condition is OFF, the call may be traffic capable of routing without query. In case of traffic of a type that can be normally received without routing information, the corresponding SSW of C4 SSW1 341 and C4 SSW2 342 performs routing processing immediately without LS query. At this time, the types of traffic that can be normally received without routing information include mobile calls, international calls, and additional service calls.

When the VoIP communication system according to the embodiment of the present invention includes a plurality of LSs (see FIG. 3), the prefix may include a setting value for determining whether to query the LS and whether to query any one of the plurality of LSs. . Specifically, if the set value of the LS query is "0", it means "OFF" and does not perform the query. If the set value is greater than 1, it means "ON". LS is determined according to the size of the set value. To this end, the SSW includes an information table for LS according to a setting value included in the prefix condition.

The C5 SSW of the lower layer connected to each of the C4 SSW1 and 2 341 and 342 has been described as one, but a plurality of C5 SSWs may be connected. Call processing between the plurality of C5 SSWs and the C4 SSW is the same as described above. Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (15)

An originating exchange that receives and processes outgoing calls, and And stores a destination exchange information in which the called number of the originating call is accommodated, and provides the destination exchange information to the originating exchange in response to a request of the originating exchange, The calling exchange exchange station forwards the outgoing call to the subscriber station corresponding to the called number if the calling exchange station information and the called exchange station information are the same, and adds the called exchange station information to the outgoing call if it is different from the called exchange station information. Relay communication system. The method of claim 1, If the originating switching center relays the originating call, further comprising a relay exchange receiving the originating call from the originating switching station, And the relay exchange station determines whether the destination exchange station is an exchange station connected to its own station using the destination exchange station information, and relays the outgoing call to the destination exchange station if the destination exchange station is an exchange station connected to its own station. The method of claim 2, And the relay switching center relays the originating call to the external network when the destination switching center information is information of an external network. The method of claim 2, And when the relay switching center receives an incoming call from an external network, requests the destination switching station information of the incoming call to the location server, and adds the destination switching center information received from the location server to the incoming call for relaying. The method according to claim 3 or 4, The external network is at least one of an external VoIP network, ITSP network and circuit network. The method of claim 2, And if the destination exchange station is not an exchange station connected to the relay exchange station, the relay exchange station relays the outgoing call to which the destination exchange station information is added to another relay exchange station to which the destination exchange station is connected to its own station. The method of claim 1, If there are a plurality of location servers, And the originating switching center requests switching station information of the called number from a corresponding location server of the plurality of location servers according to the called number. The method of claim 1, The location server, And when the called number is a telephone number before the number shift, changing the called number to a subscriber terminal number after the number shift of the called number, and transmitting the called exchange station information and the changed called number to the calling exchange station. The method of claim 1, And the called number includes a domain. In a communication method for receiving an outgoing call and forwarding the outgoing call to the subscriber station of the called number of the outgoing call, Receiving, from the originating exchange, the request of the called party information received by the subscriber station; Retrieving the destination exchange information; And providing the retrieved destination exchange information to the calling exchange. The method of claim 10, Retrieving the destination exchange information; If the called number is a telephone number before the number movement, changing the called number to the number of the subscriber station corresponding to the telephone number before the number movement; and Forwarding the called party exchange information and the changed called party number to the calling party; Communication method comprising a. A location server in a communication system, An operation management unit for receiving the request for the called exchange information received by the called subscriber station from the calling exchange station, and providing a response to the request to the calling exchange station; A query processing unit which stores exchange station information accommodated by the subscriber station for each called party number of the subscriber station, retrieves information on the destination exchange station accommodated by the receiver subscriber station according to the request, and provides the retrieved destination exchange station information as the response; Location server comprising a. The method of claim 12, The query processing unit, And store the subscriber terminal number after the number movement by phone number before the number movement. And when the called number is a telephone number before the number movement, changing the called number to a subscriber terminal number after the moving of the number, and providing the changed called number along with the searched destination switching center information in the response. The method of claim 13, The query processing unit, A location server for processing a query for each call of the plurality of request messages by creating a processor for responding to each of the plurality of request messages when a plurality of request messages are received. The method of claim 13, The query processing unit, And a redundancy structure divided into an active area for processing a query for each call of the request message and a standby area for performing the same query processing instead of the active area if the active area does not operate.