Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
  • H04L65/10—Architectures or entities
  • H04L65/1016—IP multimedia subsystem [IMS]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
  • H04L65/10—Architectures or entities
  • H04L65/102—Gateways
  • H04L65/1033—Signalling gateways
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
  • H04L65/10—Architectures or entities
  • H04L65/102—Gateways
  • H04L65/1033—Signalling gateways
  • H04L65/104—Signalling gateways in the network
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
  • H04L65/1066—Session management
  • H04L65/1069—Session establishment or de-establishment
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
  • H04L65/1066—Session management
  • H04L65/1096—Supplementary features, e.g. call forwarding or call holding

Definitions

• the subject matter of the invention is service broker interconnection and the procedure for the support of Centrex internal calls, whereby Centrex represents a functionality of a private exchange or private network within a public exchange or public network.
• Centrex represents a functionality of a private exchange or private network within a public exchange or public network.
• the technological problem that has appeared recently i.e., interconnection of TDM-based protocols and networks with all-IP based protocols and networks, can be solved with the described method within the framework of a standard network element known as the Service Broker, with standard protocols (SIP, ISUP), and with standard messages and methods (IAM, INVITE).
• the technical problem is a problem of interactions between services, protocols and networks in case we have a Centrex network. If Centrex was well-defined in the TDM world, the question remains how to provide Centrex and Centrex internal calls in case of interconnecting a TDM/NGN network on one side with an IMS network on the other side. There are no standards and instructions on how IMS and conventional networks should be interconnected in case of Centrex, or these instructions are general and incomplete.
• An example of a general standard is ETSI TS 182 024. Legacy telecommunications networks were based on TDM.
• PSTN ISDN, SS7, etc.
• PLMN e.g., GSM
• NGN SIP, H323, etc.
• PSTN ISDN, SS7, etc.
• PLMN e.g., GSM
• NGN SIP, H323, etc.
• Conventional networks are generally considered to be vertically integrated networks. This means that networks are independent of one another. Each such network has access, a network core and services. Services were provided already within individual networks (e.g., in the network core), some even outside the network (e.g., an IN network).
• Conventional networks SS7, IN, GSM, INAP
• SS7, IN, GSM, INAP are typically closed and oriented toward network elements.
• IMS network based on Session Initiation Protocol (SIP), and built on an IP platform.
• SIP Session Initiation Protocol
• It also supports other networks such as cable and computer networks.
• It is a horizontally structured network that consists of accesses (e.g., WiMAX, LTE, PSTN, NGN, ADSL, etc.), an IMS core and a service layer consisting of service enablers and servers.
• the basic problem is how to connect conventional networks to the IMS network. This is a topical issue for the period of transition when the conventional TDM network will coexist with the IMS network, which can extend over a long time-frame. For all these cases there is an element provided in IMS called a service broker intended for interaction between services, protocols and networks. Its role is defined in the standard 3GPP TS 23.002, figure 1.
• the first definition described the SCIM (Service Capability Interaction Manager), and only explained connection to a SIP AS. Later definitions also cover other ASs (e.g., Parlay X and INAP or CAMEL AS).
• Figure 2 shows the most general definition of a service broker, where the service broker resides between the IMS network core and the application layer (SIP AS, OSA SCS AS, IM-SSF AS).
• the service broker also connects to the HSS database.
• the service broker must enable interconnection between different networks, and for different services.
• Centrex represents the functionality of a private exchange or private network that is implemented with software as part of a public exchange or public network. Centrex functionality makes it possible for public subscribers to create groups either inside a single exchange or across the entire public network; inside these groups it allows the use of various supplementary services similar to PBX supplementary services. If Centrex was well-defined in the TDM world, the question remains how to provide Centrex and Centrex internal calls in case of interconnecting the TDM/NGN network on one side with the IMS network on the other side. There are no standards and instructions on how IMS networks and conventional networks should interconnect in case of Centrex, or these instructions are general and incomplete. An example of a general standard is ETSI TS 182 024.
• the application servers can be SIP ASs (for services based on SIP), OSA SCS (in the event of using open interfaces), or IM-SSF (for connection to IN/CAMEL). It can be centralized (on one of the servers only), distributed (on a larger number of servers), or hybrid (partially on one server and partially on a larger number of servers).
• the IMS standards define a detailed architecture for the transport and control layer; however, many questions still remain open as to how the application layer should be structured.
• the problem in the segment of service broker has not been addressed yet. It is a new problem that appeared with the introduction of IMS. It is a technology leapfrog that has not yet been solved and has not been fully explored. The problem occurred because transition to IMS is not possible overnight - conventional telecommunication networks as well as the IMS network will coexist simultaneously.
• the problem is related to a completely different network architecture (vertical vs horizontal), and on the other hand the problem is related to protocols which are different in IMS than they were in legacy TDM/NGN.
• the solution in this segment is left to the market and products.
• EP 2053782 A1 (A Communication Network System and Method for Providing a Service Broker Function and a Service Broker Device): the claim provides a description of a communication system and methods for the provision of the service broker function. A description of elements to which the service broker refers and the method of the service broker element operation is also provided;
• US 7693270 B2 Method and Network for Providing Service Blending to a Subscriber: the method and communications network for providing a subscriber with blended services delivered by phone and TV system.
• the claim describes data and signal changes made by the system in case of connecting a TV delivery system and a phone;
• US 2006/0104431 A1 (Method for Providing Feature Interaction Management and Service Blending): the claim describes the service broker when using a phone and a unit of the simultaneous ring set. The role of the service broker is to complete the call between the phone and the unit of the simultaneous ring set;
• WO/20 0/ 27626 A1 (Call Connection Method of Relation Call Between Networks and Service Broker System): the claim refers to the call connection method of a relation call between a network and the service broker element;
• US 7720049 (Semantic Service Broker for Telecommunications Networks): the claim provides a service broker method when we have a subscriber and a range services, for the execution of services and the use of programming languages for that purpose; - EP 2053782 A1 (A4) and WO 2008/025211 (A Communication Network System and Method for Providing a Service Broker Function and a Service Broker Device): the claim describes a network system and methods for providing the service broker function;
• the described procedure consists of the service broker providing:
• the service broker on the non-IMS side can interconnect to conventional TDM exchanges (e.g., using SS7), or to exchanges based on SIP (e.g., SIP-T, within NGN exchanges);
• the service broker is a stand-alone element. It can also be distributed, or reside in AS or in S-CSCF; - the first call message (1AM message for SS7 in TDM/NGN) from TDM/NGN to IMS contains the B subscriber number (CdPN) in the format ERN+NSN (or dicon+NSN);
• the first call message in the direction from IMS to TDM/NGN contains the B subscriber number (CdPN) in CxDN format (CxDNCd), to which LC can be added;
• the method consists of using standard networks (IMS, TDM, etc.) and network elements (SIP, SS7, Centrex, etc.). In this way, standard logic is added to the service broker element (which is a non-standard element);
• the service broker does not trigger services (it could, to an external database), but the entire logic is in the service broker element itself.
• Centrex a Centrex internal call (short number dialing). It is still possible to make a call to a public network (national number dialing);
• the described method makes it possible to connect subscribers from TDM, GSM, PLMN, NGN and other networks with subscribers of the IMS network in case of Centrex;
• NSN National significant Number
• the service broker maps ISUP parameters (CdPN, CgPN, GN, BGID, etc.) to SIP parameters (To, From, P-Asserted Identity/PAI, phone-context, otg), and vice versa;
• - Exchange Routing Numbers (ERNs) of ported Centrex numbers do not refer to the mediation exchange - the service broker, but to IMS. ERN is cut off in the service broker;
• ERN which denotes a number inside IMS
• NP DB is usually added to the number.
• ERN is cut off in the service broker
• the translation of numbers from Centrex internal numbers to NSNs is performed based on a translation table.
• a location code (LC) can be added to the Centrex internal number.
• NSN1 a national significant number
• the subscriber in case the number is ported (using NP) from TDM/NGN to IMS, the subscriber retains the same number, and can thus increase the range of possible services (from TDM/NGN to IMS), e.g., the subscriber gets some new services (such as Web browsing, Presence, IM, etc.).
• the service broker enables the mediation of parameters for such calls;
• Centrex services and internal calls are executed within exchanges where the calls are located;
• the ISUP protocol is always used. If it is transferred using SIP, it is called the SIP-T (or SIP-I) protocol - a SIP that has encapsulated ISUP messages.
• SIP-T or SIP-I protocol - a SIP that has encapsulated ISUP messages.
• Centrex mediation from TDM/NGN to IMS is possible without additional signals, methods and parameters, obviously, by taking into account certain programming logic. Used are those that are defined in the standards (ITU-T, ETSI), RFCs (IETF), or for which support is provided by the manufacturers;
• supplementary services are also ensured, e.g., for services known in TDM/NGN such as call forwarding (CFU, CFB, etc.), CT, DND, and others.
• Service support is provided to an extent as made possible by the described method. For certain services or parts of services an additional method, which is not explained within the described method, is required for the full operation of the service;
• the range of services is an intersection of all services. In the case of a call to the same exchange the range is the same, in the case of two exchanges the range is the intersection of the range of the services of the first and the second exchange. Similar applies to cases when a subscriber is migrated or resides on an IMS service platform;
• Centrex subscribers resides in NGN/TDM, in IMS and also in the service broker element;
• - subscribers can be SIP, ISDN, GSM, H323 POTS, IMS and others.
• Figure 1 the service broker as defined by the standard
• Figure 2 the service broker in the network as defined by the standard;
• Figure 3 the service broker as defined by the Service Broker Forum Figure 4 interconnecting a service broker in a converging
• FIG. 7 translation table between CxDN and NSN in the direction from IMS to TDM/NGN (for each BGID);
• Interconnection of the service broker enables the connection of the TDM and NGN environment on one side with the IMS environment on the other.
• SIP is the basis for the IMS protocol.
• SIP was upgraded for IMS.
• SIP is used to control multimedia sessions that combine audio and data.
• IMS enables several common functions, such as AAA (authentication, authorization), charging, the HSS database, and others.
• the role of the service broker element is to enable more complex service interaction scenarios. These can be accessed through certain filters. This element may contain specific intelligence and capabilities to integrate information from the network; or to execute services that are based on more complex sequences.
• the service broker uses the SIP interface and the ISC interface.
• Interaction between services refers to the process of managing network entities that require and use network services.
• the mediation of protocols and networks refers to the conversion and translation of messages from one protocol to another.
• Mediation also indicates defining whether a certain service or subscriber is authorized or not to access certain services or applications, and also to process such authorizations.
• the main task of the service broker is the selection, start and composition of services after the receipt of a SIP or TDM message. Interactions with remote servers may occur.
• a function of the service broker is also that the user profile and the applications profile are similar to trigger points in iFC.
• the service broker's task is also to provide connection within the application layer, and between the application layer and the network.
• the service broker also supports standard protocols for connecting to TDM and NGN. These protocols can be used for:
• connection to the database and administration: SNMP, XCAP, HSS and similar.
• connection is possible with the use of http, via ODBC, RPC, via SIP or via Diameter.
• the service broker can connect to various network elements such as HLR, SCP, MSC, TDM switch, NGN Softswitch, USSB gateway, Media Gateway, MGCF, SIP AS, IMS AS, S-CSCF, HSS, a charging system, and similar.
• network elements such as HLR, SCP, MSC, TDM switch, NGN Softswitch, USSB gateway, Media Gateway, MGCF, SIP AS, IMS AS, S-CSCF, HSS, a charging system, and similar.
• Figure 4 shows the interconnection of the service broker for deployment within the framework of the described method, for interconnection in the NGN/TDM/IMS network.
• the service broker itself consists of module 1 , which is intended for mediation to TDM/NGN; module 2, which is intended for mediation to IMS, and the relevant translation tables.
• the service broker network element can connect to the application layer and to the network layer.
• the application layer and the network layer can be based on TDM/NGN or IMS elements, or functionalities, respectively.
• SCP Service Control Point
• Connection between the service broker and SCP is via the INAP protocol.
• SCP consists of the part intended for services, and of a database. Number portability can also be carried out in SCP, and not only in the TDM/NGN network. In that case the part for the number portability service (NP) execution and the relevant NP database reside in SCP. Additionally, in SCP, within Centrex internal calls using NSN, it is also possible to execute IN (Intelligent Networks) services such as VPN (Virtual Private Network), FPH (Free Phone), MAS (Mobile Assistant), PRM (Premium Rate) and others. Connection to the IMS application layer is via SIP.
• IN Intelligent Networks
• IMS-based or SIP- based application servers within the IMS application layer.
• ASs application servers
• SDP service delivery platform
• the SS7 protocol is used.
• SIGTRAN protocols e.g. M3UA, M2UA, M2PA, etc.
• MGCP/H248 e.g. M3UA, M2UA, M2PA, etc.
• M3UA, M2UA, M2PA, etc. e.g. M3UA, M2UA, M2PA, etc.
• MGCP/H248 e.g. M3UA, M2UA, M2PA, etc.
• MSCs Mobile Switching Centers
• NP number portability
• a database intended for NP also resides within network 3 (TDM/NGN network).
• end-users can be SIP terminals, ISDN/POTS terminals or GSM terminals.
• the service broker connects to the IMS network 4 using SIP and the Diameter protocol.
• the service broker connects to the HSS (Home Subscriber Server) database and the S-CSCF, l-CSCF and P-CSCF elements.
• IMS terminals or other terminals can be used within the IMS network.
• the Centrex system is a functionality of a private exchange or private network that is implemented with software within a public exchange or public network.
• the Centrex functionality is a complete set of user and network signaling, supplementary services and other telecommunications services that make it possible for public subscribers to form groups either inside a single exchange or across the entire public network; inside these groups, it allows the use of various supplementary services similar to PBX supplementary services.
• Centrex is known already within the framework of TDM and also NGN.
• solutions are provided within the SS7 protocol.
• SIP-T protocol ISUP messages are transmitted via SIP. This is why the solution for NGN is based on the ISUP protocol.
• NGN is based on the ISUP protocol.
• Centrex allows the administration of a Centrex subscriber, a Centrex group, a Business Group, and other data.
• Centrex numbering through which we can make internal calls of various types (remote, quasi-remote, etc.). Internal numbering is used for internal calls (within a Centrex group). Calls within the group are charged in the way defined for a group (free-of-charge calls, reduced tariff, etc.).
• public calls can also be made, as in a public telephone network.
• the Centrex subscriber is a public subscriber who is a member of a Centrex group. Each Centrex subscriber has its own public (NSN) and internal subscriber number. Each Centrex subscriber has exactly one internal number. Centrex subscribers keep their national significant numbers (NSNs). The entire range of basic public subscriber supplementary services and additional supplementary services and/or their modifications that are offered by the membership in a Centrex group are available to the Centrex subscriber. The range of basic and supplementary services is uniform for the national significant number (NSNCd, NSNCg) and the internal number (CxDNCd, CxDNCg). The range of services is associated with the NSN.
• a Centrex group is a group of subscribers that is configured in a way to provide most of the PBX features. Apart from subscribers, a Centrex group may also comprise PBX systems (PBX subscriber). The Centrex group is determined by its CGID identity. CGID is unambiguously defined within a single call server or a single exchange. The same CGID can be used for different Centrex groups in the network, even if the Centrex groups with the same CGID are connected into a single business group.
• a business group is identified by BGID.
• a business group can extend across several exchanges.
• a Centrex group can be assigned its own public Centrex number. This number is part of the public numbering and is assigned according to the same criteria as subscriber numbers and must not be assigned to any subscriber of the call server. If a public Centrex number is assigned to a Centrex group, then it should be defined if the group is allowed to accept group Centrex calls from the entire network or just from its own business group.
• Centrex call - this is a call where the short Centrex number
• routing number a number that enables call routing to a migrated (ported) subscriber; it defines the receiving network or the receiving exchange, or an interconnection point or a network termination point;
• CGID Centrex Group Identity
• NDC+SN National Significant Number, defined as NDC+SN (e.g., 4-5561010);
• SN - Subscriber Number (e.g., 556 010)
• NSN Called Public Number
• NSN Calling Public Number
• NP DB Number Portability Data Base
• Numbers can be: called numbers (e.g., NSNCd, xDNCd), i.e., B subscriber number, and calling numbers (e.g. NSNCg, xDNCg), i.e., A subscriber number.
• IMS In IMS, subscribers are assigned to a certain AS, e.g., a Centrex AS, where services will be executed. New Centrex subscribers can be included in IMS in several ways.
• the first option is to migrate an existing subscriber from TDM/NGN to IMS. This can be a very contemporary solution, since the subscriber can thus get new services which they did not have in TDM/NGN. In addition, the subscriber retains their numbering which in this case physically resides in the IMS exchange.
• the second option is virtual NP, which is a similar solution. It is suitable for cases where a completely new subscriber is added to IMS, numbering is added in TDM/NGN, and by using NP, the subscriber is then ported to IMS.
• Virtual NP indicates that the subscriber in TDM/NGN is virtual, and was not present there until then.
• the third option is a completely new subscriber in IMS; in that case information that such a subscriber resides in IMS is added in TDM/NGN, and therefore a certain prefix is introduced.
• the described method supports interconnection for Centrex calls for all the described options.
• the first and the second option also require ERN for calls from TDM/NGN.
• the third option usually does not contain this information, but can use dicon (prefix).
• Calls that are possible within the described method are internal calls between Centrex subscribers. These are calls using a short number.
• Centrex conversion from TDM/NGN to IMS without additional parameters is possible, however, taking into account certain programming logic.
• Data for ISUP and parameters for SIP are used such as: From, To, PAI (P-Asserted-ldentity), and methods such as INVITE, 200, 302 and BYE.
• a call to the exchange can come from different networks. It can be the SS7 or SIP-T protocol.
• SIP-T also carries, within the SIP protocol, information about ISUP. In both cases the information received is contained in ISUP messages. NSN is transferred in both directions.
• ERN is obtained from NP DB.
• ERNs of Centrex numbers do not refer to the mediation exchange - the service broker, but to the IMS system Thus, ERN points to the IMS network where the Centrex subscribers (actual or ported) reside. ERN is cut off in the service broker.
• NSNCg From the TDM/NGN network, information for CxDNCg, CxDNCd, ERN and NSNCd, BGID and optionally also for NSNCg, is sent in the 1AM message of the ISUP protocol. If NSNCg is not present, it is obtained by the service broker. Data is transmitted by the ISUP protocol, the BGID, CgPN, CdPN parameters and the Generic Parameter. In case of a Centrex call from TDM/NGN to IMS, information about the number contained in the SIP protocol of the INVITE message (method) is transmitted to the IMS network by the To, From and PAI parameters.
• the CxDNCd information is contained in the To and phone-context parameter
• the NSNCg information is contained in the From parameter
• the CxDNCg information is contained in P-Asserted-ld (PAI). All messages, methods and parameters are defined in existing standards (ITU-T, ETSI, IETF RFC). The implementation method in the service broker element with a description of mediation is illustrated in figure 5.
• Centrex internal calls from IMS to TDM/NGN are also possible; however, taking into account certain programming logic.
• the ISUP parameters Generic Number, CdPN, CgPN, BGID are used to make a call; parameters such as From, To, PAI, and methods such as INVITE, are used within the SIP parameters.
• a call to the exchange comes from the IMS network using SIP and the INVITE method (message).
• the CxDNCd information is contained in the To and the phone-context parameter
• the LC+CxDnCg information with the otg parameter and the BGID value is contained in the From parameter
• the LC+CxDNCg information is contained in the PAI parameter, which does not contain the otg parameter.
• LC can be present in both cases, or not.
• the service broker processes this information. Centrex subscribers are entered in Centrex tables where NSN is read based on the Business Group ID (BGID) and the Centrex internal number (CxDN). Because the table is uniform, both called and calling numbers are read.
• the service broker has a translation table for each BGID (Centrex group). On the basis of the translation table, and taking into account the BGID and CxDN information, data for NSN is read. The information is then translated from SIP to ISUP messages. An ISUP 1AM message is coded toward TDM/NGN - BGID, NSNCd, NSNCg, and Generic Number information is sent (CxDNCg and CxDNCd data). All messages, methods and parameters are defined in existing standards (ITU-T, ETSI, IETF RFC). An exception is the otg parameter, which is not standardized in IETF RFC. Even though the parameter is not standardized, it is used by a number of telecommunications equipment manufacturers.
• Figure 7 shows how the translation table works. The table applies to each individual BGID.
• the described method allows the set-up of Centrex calls even in cases of subscribers ported with the use of NP (Number Portability).
• NP Network-to-Network Interface
• SS7 SS7
• Service Portability which is defined in the NP standards.
• a Centrex subscriber is locally ported from TMD/NGN to IMS. The subscriber in IMS thus obtains a wider range of services.
• a locally ported subscriber is entered in the NP database (DB NP) in the form that is known from inter-operator portability.
• DB NP NP database
• NSN National significant Number
• ERN Exchange Routing Number
• the ACQ method (reasonable for a larger number of ported numbers) is activated in the originating exchange (TDM/NGN), and triggers a query in the NP database based on a digit analysis.
• the depth of the digit analysis (only the prefix or the entire called number) is set administratively depending on the number of locally ported subscribers. If there are several locally ported numbers in a compact block, then a query is activated according to a block; however, if the ported numbers are scattered, then it is more reasonable to make a query in NP DB according to the entire number.
• the QoR method In addition to the ACQ method there is also the QoR method (it generates more traffic, so it is used for a smaller number of ported numbers). With the QoR method, a message about a ported subscriber (SS7 REL message, cause #14) is transmitted to the originating exchange. A query in NP DB is made in the originating exchange. Since this method is used for inter-operator portability, additional network planning is required to prevent interaction between the inter-operator and locally ported subscribers.
• NP DB NP database
• Queries in the NP database can also be made directly from the service broker element.
• the NP database can reside in SCP; connection is via INAP.
• Mediation from the service broker to IMS is possible directly or through a database (e.g., HSS or quasi-IMS).
• a database e.g., HSS or quasi-IMS.
• INVITE message is sent to IMS.
• Access to the database is possible with the use of standard LIA and LIR messages of the DIAMETER protocol. This is direct access to the IMS HSS database.
• Access to the database is also possible with the use of conventional SIP messages, e.g., if direct DIAMETER access to HSS is not available.
• the IMS database may be accessed in the location database (LDB) itself. And in this database data conversion is carried out, e.g., for data from HSS.
• the first INVITE arrives to LDB.
• LDB returns 302 with the cause "Temporarily moved".
• the service broker confirms the receipt of the 302 signal to LDB with ACK.
• Contact contains the IP address for the first and the second IMS exchange (IP1 and IP2). Based on the result, the service broker sends an INVITE message to CSCF1 (with the IP1 address), or to CSCF2 (with the IP2 address). This is shown in Figure 9. It is also possible to select and use an additional database (e.g. LDB2) in case LDB does not respond or is overloaded.
• the location database can also be placed in the service broker element itself.
• the described method In addition to support for the operation of Centrex internal calls, the described method also provides support for supplementary services. These are services as known in TDM /NGN. Support is provided to such an extent as made possible by the described method. An additional method, which is not described within the suggested method, is necessary for the complete operation of certain services or parts of services.
• Call Completion Supplementary Services such as Call Intrusion - CINT, Call Intrusion Protection - CINTP, Camp On Busy - CAMP, etc.
• Call Offering Services such as Call Transfer Controlled - CTC, Night Service (Individual, Group) - NS, NSG, Call Pick Up, Single - CPUS, Call Pick Up, Group - CPUG, Multi-level Precedence and Preemption Service - MLPP, etc.
• Centrex supplementary services such as Abbreviated Dialing, Group List - ABDG Call Forwarding for External Call Only, Emergency Call for Centrex Users, CTX Presentation Number, Interception of Calls for CTX - IOC, Announcement Service For CTX, First Dial Tone for CTX), and others. Support for the abovementioned supplementary services within the described method is ensured in part or in whole.
• the described service broker solution allows the interconnection of conventional TDM/NGN networks (PLMN, GSM, PSTN, ISDN, SS7, etc.) to new IMS networks in cases of Centrex internal calls. This is applicable if one of the Centrex subscribers is in TDM/NGN and the other is in IMS and also in a subscriber in IMS is migrated to TDM/NGN. With the described solution it is possible to extend a private Centrex network from TDM/NGN to IMS.
• IMS elements TDM network elements, ISUP, SIP, service broker, NGN, IMS, etc.
• Centrex supplementary services such as call forwarding (CFU, CFB, etc.), conference calls (CONF), call intrusion (CINT), call transfer (CT), do not disturb (DND), line hunting (LH), anonymous call rejection (ACR), number presentation (CLIR, CLIP, etc.) and others;
• the entire logic for interworking between various networks and services resides in a single network element, i.e., the service broker element.
• the above-mentioned logic connects to various parts of the network such as interfaces for H248/MGCP, SIGTRAN, SIP, SIP-T, and others,
• the service broker does not become a traffic bottleneck (additional traffic from the service broker to SCP and back for each call to the ported number). In this case, information as prepared within the TDM/NGN exchanges, reaches the service broker.

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Citations (8)

• 2011
  • 2011-07-12 SI SI201100252A patent/SI23819A/sl not_active IP Right Cessation
• 2012
  • 2012-07-03 WO PCT/SI2012/000043 patent/WO2013009266A1/en active Application Filing

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