CN1913503A - Control method and system of session route path - Google Patents

Abstract

This invention provides a method for controlling session route paths and a system, in which, an appied server determines a metwork entity in the IMS domain corresponding to the session and provides it to S-CSCF, which routes the session to the network entity in the IMS and the network entity in it routes it to the network entity in the circuit exchange domain. This invention does not make sound coding and decoding conversion between DTM and IP loads to two sections of entry and outlet calls of a same session so as to reduce the transmission times of the sound coding and decoding to avoid the reduction of phone service. This invention prolongs the IP load path in the IMS domain and reduces the DTM load path to increase the usability of IP load.

Description

A kind of session route path control method and system

Technical field

The present invention relates to the network communications technology field, be specifically related to a kind of session route path control method and system.

Background technology

From 3GPP R5 (the 3rd Generation Partnership Project 3rd Generation Partnership Project) stage, UMTS (universal mobile telecommunications system) core net is divided into CS (circuit switching), PS (packet switching) and three subsystems of IMS (IP Multimedia System).

CS territory (Circuit Switched Domain circuit commutative field) is used for providing to the user connection of Circuit Service.The CS territory mainly comprises: MSC (MSC Server/CS-MGW, Mobile Switch CenterServer/CS-Media GateWay, Mobile Switching Center Server/circuit domain-media gateway), GMSC (Gateway MSC gateway MSC) and IWF (InterWorking Function, IWF).Wherein, MSC finishes the exchange and the signaling controlled function of circuit switched type business; GMSC is the MSC that finishes mobile subscriber's routing addressing function in a certain network, can close with MSC if set up separately; IWF and MSC are closely related, finish the signaling translation function between PLMN (public land mobile net) and ISDN (integrated services digital network), PSTN (public telephone switching network), PDN (Packet Data Network packet data network), thereby the realization network interworking, the concrete function of IWF is closely related with the kind of professional and network.

PS territory (Packet Switched Domain) is used for providing to the user connection of packet-type business, and the PS territory mainly comprises: GSN (GPRS Support Node), BG (borde gateway), HLR/AuC (Home Location Register/authentication center), VLR (VLR Visitor Location Register), EIR (equipment identity register), MSC etc.Wherein, GSN finishes the transmission of Packet Service user's grouping bag, GSN comprises SGSN (Serving GPRS Support Node) and GGSN (Gateway GPRS Support Node), SGSN provides being connected of core net and wireless access system BSS, RNS, finish the functions such as mobile management, session management of multicomponent data business, with management MS moving and communication service in the mobile network; GGSN is the interface between mobile communication system and other public data network, and simultaneously, GGSN also has the function of inquiring position information.In addition, SGSN and GGSN all provide charge information.BG be used to finish two between GPRS network intercommunication, guarantee the fail safe of network interworking.HLR is used to finish the management of user contracting data and positional information, user contracting data such as MSISDN, IMSI, PDP ADDRESS, signatory telecommunication service and supplementary service and the professional scope of application thereof etc., positional information such as MSRN, MSC/VLR number, SGSN number, GMLC etc.AUC is mainly used in storage user's authentication arithmetic and key.VLR is used to handle the various data messages of visitor.EIR is used to store customer equipment identification IMEI information.

IMS is a subsystem that is superimposed upon in the WCDMA network that increases in the 3GPP R5 stage on the existing packet domain, adopt the bearer path of packet domain for its upper strata control signaling and media delivery, and introduce Session Initiation Protocol as professional control protocol, utilize simple, the easy expansion of SIP, media combination characteristics easily, by business control is separated with carrying control, provide abundant multimedia service.Major function entity among the IMS comprise functions such as control user registration, session control conversation control entity CSCF, provide miscellaneous service logic control function application server AS, manage the home subscriber server HSS of user contracting data concentratedly and be used to realize MGCF/IM-MGW (MGCF) with the circuit switching net interconnecting.The user is by current location agent node P-CSCF access IMS, and session and professional triggering control reach with the business control of AS and then finished by the home domain service node S-CSCF of its registered place alternately.

HSS in the IMS system is the superset of HLR, can compatible HLR on the function, but because factors such as networking process, HSS and CS/PS HLR adopt situation about setting up separately probably in the concrete networking.

The IMS framework of 3GPP standard definition has solved the roam charge that the required solution of multimedia service is provided under the IP carrying comprehensively, QoS (service quality), but the problems of operation that safety guarantee etc. are crucial, its framework and thinking have obtained industry and have generally acknowledged, 3GPP2, TISPAN has all carried out the definition of corresponding IP multi-media network framework and business system with the 3GPP model as basis and reference, 3GPP has also begun to insert and UMTS intercommunication such as I-WLAN (Interworking of WLAN at WLAN (WLAN (wireless local area network)), the WLAN intercommunication), fixed broadband inserts IMS such as FBI (Fixed Broadband access to IMS, fixed broadband inserts IMS) and towards the all-IP net such as the AIPN subject studies such as (All-IP Network complete IP networks) of multiple access technology, the user can signatory insert IMS by single multimode terminal or polytype different terminals via the Access Network of different access technologies according to it, with what obtain to unify, the multimedia service that comprises VoIP (Voice over IP, IP-based voice) business etc.

Because the business platform of IMS framework can provide IP-based speech business equally, it is the VoIP business, and operator can at based on the speech business in CS territory with implement different charging rates respectively based on the speech business in IMS territory, therefore, for unfounded call/session still, need select the route of called subscriber between CS territory or IMS territory neatly according to the routing policy of operator and user's preference setting; And, because operator also can provide respectively in different regions based on the speech business in CS territory or based on the speech business in IMS territory, like this, because user's mobility, for the call/session of having set up, when the user speech business takes place in CS territory and IMS territory is switched, need to guarantee the continuity of call/session, to guarantee that speech business is two seamlessly transitting of same area not.

At present, 3GPP has just passed through research CS calling and has passed through IP-CAN (IP-ConnectivityAccess Network IP, connective access network) insert the work problem of business continuance problem between the VoIP business that IMS provides, the emphasis of research contents concentrates on called route control and switches two aspects.

At present 3GPP has proposed a kind of calling controlling schemes of static anchor point (IMS control static anchoring) of IMS control, to solve in two territories, as CS territory and IMS territory, between the problem switched.The core concept of this scheme is, for no matter from the CS territory or the call/session initiated of IMS territory, all this call/session is toggled to the AS (Application Server, application server) in the IMS territory, call/session is carried out grappling control (Anchoring control) by this AS.Like this, follow-uply no matter take place between CS territory to the territory in IMS territory to switch or the IMS territory takes place switches between the territory in CS territory, all the call/session of grappling is carried out follow-up switching controls and handle by this AS.

Since among the IMS session control mode itself just can be very easily in call path anchor point AS of insertion session is controlled, promptly make session be toggled to AS by defining iFC.And in call path, insert an anchor point AS not too easily for the calling control mode in CS territory itself, therefore the calling of initiating at the CS territory is toggled to the process of anchor point AS, the 3GPP standard has been described multiple scheme at present: the initial call of initiating when being the CS territory for Calling Side, promptly receiving the calling of initiating behind the call setup message of UE for Calling Side VMSC, can there be the control of network side route promptly to use the CAMEL scheme, USSD and Notify scheme are promptly used in control with the end side route, and two kinds of control models route the call to anchor point AS.The initial call of initiating when being the CS territory for callee side, the GMSC that is called home network is after receiving the calling that comes from Calling Side, according to the calling that GMSC initiates after to the called party information analysis, can use CAMEL scheme and signaling catching scheme to route the call to anchor point AS.

This function that initial call is routed to anchor point AS is called DRF (Domain Routing Faction inter-domain routing function) function, for the CS territory, entity with DRF function can be gsmSCF, and for the IMS territory, the entity with DRF function can be an AS.Routing decision entity gsmSCF in the CS territory can be arranged in same physical entity with the routing decision entity A S in the IMS territory.

The grappling controlled function of above-mentioned AS is used to realize that the cardinal principle of switching between the territory is, when calling is initially set up, as the calling of UE (A) initiation at UE (B), insert an anchor point AS by gsmSCF or the AS with DRF function in the call path of Calling Side UE (A), this AS enables the B2BUA function and is divided into AS in order to the calling with Calling Side and stops section and AS and initiate sections two sections.AS termination section is the call leg between UE (A) AS, and AS initiation section is the call leg between the AS-UE (B).Follow-up in the process of calling out, UE (A ') detect when switching condition satisfies between the territory, wish that will the current calling of carrying out switching to UE (A ') from UE (A) carries out follow-up calling and control, UE this moment (A ') then initiates a new calling at the AS that grappling control is carried out in current calling, AS is after receiving this calling, judge in the time of to carry out switching between the territory, then AS initiates the new calling of initiating of UE (A ') and AS section to continue, discharge the calling of AS termination section then, like this, under the control of anchor point AS, make continuing that UE (A ') and same UE (B) carried out calling out, discharge the call leg between previous UE (A)-AS, finished UE (A) to the switching between the UE (A ').This grappling control is carried out in calling, and the function of carrying out hand-off process between the territory when switch taking place is called DTF (forwarding function between Domain Transfer Function territory) function, under static anchor point scheme, the entity with DTF function is an AS in the IMS territory.

Routing decision point gsmSCF or AS with DRF function can be arranged in same physical entity with the AS with DTF function.

Here, UE (A) can be the terminal in CS territory, and UE (A ') can be the terminal in IMS territory, switches to the calling of UE (A ') by UE (A), the same calling that has realized user A from the CS territory to the call continuity the IMS territory.

Same, when calling is initially set up, can in the call path of Calling Side UE (B), insert an anchor point AS equally, in order to the calling control of switching between the territory of realizing follow-up callee side.

When accompanying drawing 1 made a call as caller for the user in CS territory, under the network side route control model, i.e. the calling of using CAMEL mechanism to initiate in the CS territory was toggled to the flow chart that AS carries out anchor point.

Among Fig. 1, make a call at step 1-1, the UE that is registered to VMSC (Visited Mobile Switch Center Visited Mobile Switching Center).

Calling is triggered among the gsmSCF with DRF function according to the CAMEL Subscription Information of Calling Side to step 1-2, VMSC.

Generate a routing number IMRN (IMS Routing Number) who points to the AS in the IMS territory to step 1-3, gsmSCF with DRF function, make VMSC route the call on this DTF according to this routing number with DTF function.GsmSCF with DRF function can construct IMRN by append methods such as Call Reference Number behind the identification information DTF of DTF PSI (DTF Public Service Identities DTF public service identity), and the gsmSCF that has the DRF function then is handed down to VMSC by CAMEL connect message with IMRN.

Route the call to the MGCF (MGCF) in the IMS network of calling subscriber ownership according to IMRN to step 1-4, VMSC.

The called party information of judging in the IAM message to step 1-5, MGCF is to point to the IMRN of the AS with DTF function, then sends INVITE to I-CSCF, and the called party information Requested-URI in this message is the TELURI form of IMRN.

Inquire about routing iinformation according to Requested-URI to HSS to step 1-6, I-CSCF, obtain the AS address information that is associated with this IMRN, promptly have the AS address information of DTF function, I-CSCF transmits INVITE to the AS with DTF function then.Here, can return AS information according to the IMRN that comprises DTF PSI information, in HSS, need to dispose DTF PSI data with corresponding relation with AS address information of this DTF function with DTF function in correspondence in order to support HSS.

To step 1-7, have called party information that the AS of DTF function receives and comprise the session of IMRN of DTF PSI information after, grappling control is carried out in session, promptly trigger B2BUA (back-to-back user agent) function, stop AS and receive session, initiate a new session at former called party information then, the AS that promptly has the DTF function is by obtaining the S-CSCF information of calling subscriber's side, then with the Sh interface of HSS, will talk about and route to S-CSCF, and will talk about by this S-CSCF and to route to former callee side.

Here, route the call in the process of former callee side at S-CSCF, when former called party information is the Tel-URI form, S-CSCF carries out ENUM DNS (E.164 Number Domain Name System E.164 domain name converting system) translation function, if original called party number can be converted to SIP URI form, then follow-up calling route is carried out in the IMS territory, otherwise, S-CSCF routes the call to the BGCF (Breakout Gateway Control Function borde gateway controlled function) in this IMS territory, to call out finally by BGCF and to route to PSTN (public switched telephone network (PSTN)) or CS territory via MGCF, at last by PSTN or CS territory with call proceeding to called.When the AS with DTF function enabled the B2BUA function, for the session that stops at DTF with in the new session of initiating of DTF, DTF controlled to switch between the territory that may initiate subsequent user all to its maintenance state.

Because the calling subscriber visits the CS territory on ground and not necessarily supports CAMEL, therefore need consider that other alternative route the call to AS, provide in the standard of 3GPP at present under the end side route control model based on USSD (Unstructured Supplementary Service Data unstructured supplementary data traffic) with based on two kinds of mechanism of Notify (notice).Wherein, USSD mechanism is applied to UE and is not registered to IMS territory, UE when VMSC makes a call, that the called address information in the call signaling is carried is the DTF PSI that points to the AS with DTF function, thereby VMSC routes the call to the AS that has the DTF function in the IMS territory via MGCF.And real called party information, number information as UE (B), be in the USSD signaling that the gsmSCF with DRF function sends, to carry by UE, like this, after the gsmSCF with DRF function receives the USSD signaling, carry out alternately with AS with DTF function, the real called party information of its current session that receives of notice DTF, it is the number information that carries UE (B) in the USSD signaling, thereby the AS with DTF function carries out grappling to the calling that the UE that receives initiates, be that AS starts the B2BUA function, stop AS and receive session, initiate a new session at former called party information then, the former called party information here obtains from the USSD signaling that the gsmSCF with DRF function receives.Subsequent treatment is as described in the step 7 of Fig. 1, and the former called party information in the new session of initiating according to AS continues after will talking about and routing to the called subscriber.Notify mechanism is applied to UE and has been registered to IMS territory, UE when VMSC makes a call, called address information in the call signaling is pointed to the DTF PSI of the AS with DTF function when carrying, thereby VMSC routes the call to the AS that has the DTF function in the IMS territory via MGCF.And real called party information, number information as UE (B), be that UE by the current IMS of being registered to territory carries in the SIP Notify signaling that the AS with DRF function sends, like this, after the AS with DRF function receives SIP Notify signaling, carry out alternately with AS with DTF function, the real called party information of its current session that receives of notice DTF, it is the number information that carries UE (B) in the SIP Notify signaling, thereby the AS with DTF function carries out grappling to the calling that the UE that receives initiates, be that AS starts the B2BUA function, stop AS and receive session, initiate a new session at former called party information then, the former called party information here obtains from the SIP Notify signaling that the AS with DRF function receives.Subsequent treatment is as described in the step 7 of Fig. 1, and the former called party information in the new session of initiating according to AS continues after will talking about and routing to the called subscriber.

As preceding analysis, the initial call of initiating when being the CS territory for callee side, the GMSC that is called home network according to the calling that GMSC initiates after to the called party information analysis, can use CAMEL scheme and signaling catching scheme to route the call to anchor point AS after receiving the calling that comes from Calling Side.Wherein the CAMEL scheme is applicable to that GMSC supports that the signaling catching scheme is applicable to that GMSC can not support under the situation of CAMEL ability under the situation of CAMEL ability.Accompanying drawing 2, uses CAMEL mechanism will receive the calling that comes from Calling Side and is toggled to the flow chart that anchor point AS carries out grappling when called for the user in CS territory does in the CS territory.

When the MSISDN of called party information belongs to the CS territory at step 2-1, in calling out,, when carrying out called route, route the call to GMSC in the CS territory or the calling initiated of PSTN.

To step 2-2, GMSC after receiving the calling that comes from Calling Side, called party information is analyzed, GMSC sends SRI message to obtain called subscriber's routing iinformation to HLR then, because this GMSC supports the CAMEL ability, so GMSC sends the CAMEL support information that carries relevant parameters indication GMSC in the SRI message to HLR.HLR returns the callee side CAMEL Subscription Information T-CSI of indication user for CS-IMS user.

Trigger the CAMEL business to step 2-3, GMSC according to the T-CSI that receives, send IDP message, the route indication of request DRF to gsmSCF with DRF function.

Obtain current data and the state in user IMS territory to step 2-4, gsmSCF with DRF function from HSS.

Obtain current data and the state in user CS territory to step 2-5, gsmSCF with DRF function from HLR.

Generate a routing number IMRN (IMS Routing Number) who points to the AS in the IMS territory to step 2-6, gsmSCF with DRF function, make GMSC route the call on this DTF according to this routing number with DTF function.GsmSCF with DRF function can construct IMRN by append methods such as Call Reference Number behind the identification information DTF of DTF PSI (DTF Public Service Identities DTF public service identity), and the gsmSCF that has the DRF function then is handed down to GMSC by CAMEL connect message with IMRN.

Route the call to the MGCF in the IMS network of called subscriber ownership according to IMRN to step 2-7, GMSC.

To step 2-8, with step 1-5.To step 2-9, with step 1-6.

To step 2-10～step 2-13, have called party information that the AS of DTF function receives and comprise the session of IMRN of DTF PSI information after, grappling control is carried out in session, promptly trigger B2BUA (back-to-back user agent) function, stop the session that AS receives, initiate a new session then at former called party information, the AS that promptly has the DTF function is by obtaining the S-CSCF information of called subscriber's side with the Sh interface of HSS, then, will talk about and route to S-CSCF, and will talk about by this S-CSCF and to route to former callee side.

Here, when the AS with DTF function initiates a new session at former called party information, need carry out route analysis to former called party information by AS with DRF function, judge to need to talk about at AS and route to when continuing in the CS territory with DRF function, AS with DRF function is based on the CSRN (CS Routing Number CS territory routing number) of former called party information structure Tel-URI form, and what have then that the AS of DTF function initiates is CSRN at the called party information Requested-URI in the new session of former called party information.

Here, route the call in the process of former callee side at S-CSCF, when former called party information is the Tel-URI form, S-CSCF carries out ENUM DNS (E.164 Number Domain Name System E.164 domain name converting system) translation function, if original called party number can be converted to SIP URI form, then follow-up calling route is carried out in the IMS territory, otherwise, S-CSCF routes the call to the BGCF (Breakout Gateway Control Function borde gateway controlled function) in this IMS territory, to call out the GMSC that finally routes to the CS territory by BGCF via MGCF, by GMSC that call proceeding is extremely called at last.When the AS with DTF function enabled the B2BUA function, for the session that stops at DTF with in the new session of initiating of DTF, DTF controlled to switch between the territory that may initiate subsequent user all to its maintenance state.

Receive the incoming call IAM message of MGCF to step 2-14, GMSC after, therefrom parse former called subscriber's MSISDN (using the mode of CAMEL business or other switch technology), after based on the MSISDN that parses called party information being analyzed then, GMSC sends SRI message to obtain called subscriber's routing iinformation to HLR, because this GMSC supports the CAMEL ability, so GMSC sends the CAMEL support information that carries relevant parameters indication GMSC in the SRI message to HLR.HLR returns the callee side CAMEL Subscription Information T-CSI of indication user for CS-IMS user.

To step 2-15, with step 2-3.

Judge AS to step 2-16, gsmSCF with DRF function and anchor point control has been carried out in this calling with DTF function, IMRN does not then reallocate, directly issue continue message to GMSC, GMSC continues follow-up calling after receiving continue message, being GMSC sends the routing iinformation (GMSC in the SRI of this transmission message carry restrain T-CSI parameter) of SRI message to obtain the called subscriber to HLR, and the called subscriber's that returns according to HLR of GMSC routing iinformation continues after routing the call to called subscriber's visit VMSC then.

Accompanying drawing 3, uses signaling catching mechanism will receive the calling that comes from Calling Side and is toggled to the flow chart that anchor point AS carries out grappling when called for the user in CS territory does in the CS territory.

At step 3-1, with step 2-1.

To step 3-2, GMSC after receiving the calling that comes from Calling Side, called party information is analyzed, GMSC sends SRI message to obtain called subscriber's routing iinformation to HLR then, because this GMSC does not support the CAMEL ability, so GMSC sends the CAMEL support information that can not carry relevant parameters indication GMSC in the S RI message to HLR.Therefore HLR can not return the callee side CAMEL Subscription Information T-CSI of indication user for CS-IMS user to GMSC.But directly to returning called routing iinformation, thereby call anchor can't have been fixed on the AS that has the DTF function in the IMS territory.Therefore in order to make that calling can be toggled to the AS that has the DTF function in the IMS territory before the called routing iinformation that GMSC gets from HLR calls out grappling, therefore between GMSC and HLR, insert signaling catching entity SRF (Signalling RelayFunction signaling forwarding capability), this SRF has the DRF function, interception GMSC carries out corresponding intra domain routing policy control and treatment after analyzing to the SRI message of HLR transmission and to this message.

Obtain current data and the state in user IMS territory to step 3-3, SRF with DRF function from HSS.

Obtain current data and the state in user CS territory to step 3-4, SRF with DRF function from HLR.

Generate a routing number IMRN (IMS RoutingNumber) who points to the AS in the IMS territory to step 3-5, SRF with DRF function, make MSC route the call on this DTF according to this routing number with DTF function.GsmSCF with DRF function can construct IMRN by append methods such as Call Reference Number behind the identification information DTFPSI of DTF (DTF Public Service Identities DTF public service identity), the function that has the SRF imitation HLR of DRF function is then returned SRI-Ack message to GMSC, in this SRI-Ack message IMRN is sent to GMSC as called routing iinformation.

To step 3-6, with step 2-7.To step 3-7, with step 1-5.To step 3-8, with step 1-6.To step 3-9～step 3-12, with step 2-10～step 2-13.

Receive the incoming call IAM message of MGCF to step 3-13, GMSC after, use certain switch technology therefrom to parse former called subscriber's MSISDN, after based on the MSISDN that parses called party information being analyzed then, GMSC sends SRI message to obtain called subscriber's routing iinformation to HLR.The SRF that this calling is had the DRF function equally tackles, SRF with DRF function judges this calling is handled, then this not being tackled the SRI that gets off analyzes, do not carry out corresponding intra domain routing policy control and treatment, directly transmit this SRI message, and the SRI-Ack forwards that the HLR that receives is returned is to GMSC to HLR.GMSC continues route the call to called subscriber's visit VMSC according to the routing iinformation of the called subscriber among the SRI-Ack that receives after then.

In addition, because operator when carrying out number assignment, can distribute corresponding M SISDN number for the user in IMS territory, in order to realize the calling of CS territory or PSTN Client-initiated to IMS territory user.Therefore, when the MSISDN user in the customer call IMS territory among CS territory or the PSTN, CS territory or PSTN Client-initiated need be called out equally and route to the called subscriber and belong to the grappling that the AS with DTF function in the IMS territory calls out, and switch between the territory that may initiate subsequent user by AS and control.

Receive the incoming call IAM message of MGCF to step 3-14, GMSC after, can use certain switch technology therefrom to parse former called subscriber's MSISDN, then, after based on the MSISDN that parses called party information being analyzed, GMSC sends SRI message to obtain called subscriber's routing iinformation to HLR.The SRF that this calling is had the DRF function equally tackles, SRF with DRF function judges this calling is handled, then this not being tackled the SRI that gets off analyzes, do not carry out corresponding intra domain routing policy control and treatment, directly transmit this SRI message, and the SRI-Ack forwards that the HLR that it receives is returned is to GMSC to HLR.GMSC continues route the call to called subscriber's visit VMSC according to the routing iinformation of the called subscriber among the SRI-Ack that receives after.。

Accompanying drawing 4 is the caller user for the user of CS territory or PSTN, and when the MSISDN user in the IMS territory was the called subscriber, the network based analysis to called number of CS territory or PSTN routed the call to the IMS territory and is toggled to the flow chart that anchor point AS carries out grappling.

At step 4-1, because called subscriber's MSISDN belongs to the IMS territory, CS territory that then makes a call or PSTN network route the call to the called subscriber and belong to MGCF in the IMS territory.

Convert MSISDN to Tel-URI to step 4-2, MGCF, and send INVITE to I-CSCF, the called party information Requested-URI in this message is the TELURI form of called MS ISDN.

Inquire about routing iinformation according to Requested-URI to HSS to step 4-3, I-CSCF, obtain the S-CSCF address information that this user registers in the IMS territory, and will talk about and route to corresponding S-CSCF, if the active user is not registered in the IMS territory, then I-CSCF will talk about and route to one among the interim S-CSCF who distributes of non-registered users.

Session is triggered among the AS with DRF function according to iFC (initial Filter Criteria initial filter standard or norm) to step 4-4, S-CSCF.

Obtain the login state and the data in user's current I MS territory from HSS to step 4-5, AS with DRF function.

Obtain the login state and the data in user's current C S territory from HLR to step 4-6, AS with DRF function.

To step 4-7, have the AS of DRF function by called party information is carried out route analysis, judge to need to talk about at AS and route to when continuing in the CS territory with DRF function, have the CSRN (CS Routing Number CS territory routing number) of the AS of DRF function, trigger the DTF function then based on former called party information structure Tel-URI form.

To step 4-8～step 4-9, have the session that the AS of DTF function receives the AS with DRF function and carry out grappling control, promptly trigger B2BUA (back-to-back user agent) function, stop the session that AS receives, initiate a new session at former called party information then, the called party information Requested-URI in this new session is the CSRN with AS structure of DRF function.The AS that promptly has a DTF function then, will talk about and route to S-CSCF by obtain the S-CSCF information of called subscriber's side with the Sh interface of HSS, and will be talked about by this S-CSCF and to route to former callee side.

Here, will talk about in the process that routes to former callee side at S-CSCF, because the Requested-URI that has in the new session of initiating of the AS of DTF function is CSRN, can not convert thereof into SIP URI form after the S-CSCF process ENUM DNS translation function, therefore S-CSCF will talk about the BGCF that routes to this IMS territory, session is finally routed to the GMSC in CS territory by BGCF via MGCF.

When the AS with DTF function enabled the B2BUA function, for the session that stops at DTF with in the new session of initiating of DTF, DTF controlled to switch between the territory that may initiate subsequent user all to its maintenance state.

Receive the incoming call IAM message of MGCF to step 4-10, GMSC after, therefrom parse former called subscriber's MSISDN (using the mode of CAMEL business or other switch technology), after based on the MSISDN that parses called party information being analyzed then, GMSC sends SRI message to obtain called subscriber's routing iinformation to HLR, because this GMSC supports the CAMEL ability, so GMSC sends the CAMEL support information that carries relevant parameters indication GMSC in the SRI message to HLR.HLR returns the callee side CAMEL Subscription Information T-CSI of indication user for CS-IMS user.

To step 4-11, with step 2-3.

Judge AS to step 4-12, gsmSCF with DRF function and grappling control has been carried out in this calling with DTF function, IMRN does not then reallocate, directly issue continue message to GMSC, GMSC continues follow-up calling after receiving continue message, being GMSC sends the routing iinformation (GMSC in the SRI of this transmission message carry restrain T-CSI parameter) of SRI message to obtain the called subscriber to HLR, and the called subscriber's that returns according to HLR of GMSC routing iinformation continues after routing the call to called subscriber's visit VMSC then.

In the calling controlling schemes that in the call continuity problem, proposes at present by the static anchor point (IMS control staticanchoring) of IMS control, for Calling Side, initiate in the CS territory when calling out, then need the VMSC on the calling caller visit ground from the CS territory that will initiate to route to the AS with DTF function in the caller ownership IMS territory, the grappling of being called out by this AS is also carried out switching controls between follow-up possible territory.After the AS with DTF function carries out grappling to calling, AS with DRF function then carries out route analysis to real former called party information in the calling of former caller visit CS territory initiation, when judging former calling, the AS with DRF function need route to go back to the CS territory, then produce CSRN according to former called party information, trigger the DTF function then, the AS with DTF function will call out the CS territory that route is returned called ownership according to CSRN.Like this, the whole call path of the initial call of initiating when being the CS territory for Calling Side is the CS territory of IMS territory-called ownership of CS territory-caller ownership on caller visit ground, carries thereby the mode of the foundation of carrying in the call path is DTM carrying-IP carrying-DTM.

Same, for callee side, need terminate in the CS territory when calling out, then to need the calling that the GMSC in the called ownership CS territory receives is routed to the AS with DTF function in the called ownership IMS territory, the grappling of being called out by this AS is also carried out switching controls between follow-up possible territory.After the AS with DTF function carries out grappling to calling, AS with DRF function then carries out routing decision to real former called party information in the calling of former called ownership CS territory initiation, when determining former calling, the AS with DRF function need route to go back to the CS territory, then produce CSRN, trigger the AS that the DTF function has the DTF function then and will call out the CS territory that route is returned called visit according to CSRN according to former called party information.Like this, the whole call path of the initial call of initiating when being the CS territory for callee side is the CS territory of IMS territory-called visit of the CS territory-called ownership of called ownership, thereby the mode of the foundation of carrying in the call path is DTM carrying-IP carrying-DTM carrying.

According to last analysis, originally the process of the called subscriber B in the calling subscriber A calling CS territory in the CS territory can be expressed as compactly: A (caller visit CS territory)-B (called ownership CS territory)-B (called visit CS territory), the mode of setting up of carrying in its call path is: DTM carrying-DTM carrying.After introducing static anchor point scheme, if when only needing that Calling Side carried out grappling, then calling procedure is changed into: A (caller visit CS territory)-A (caller ownership IMS territory)-B (called ownership CS territory)-B (called visit CS territory), thus the mode of setting up of carrying in the call path is changed into: DTM carrying-IP carrying-DTM carrying; If when only needing that callee side carried out grappling, then calling procedure is changed into: A (caller visit CS territory)-B (called ownership CS territory)-B (called ownership IMS territory)-B (called visit CS territory), thus the mode of setting up of carrying in the call path is changed into: DTM carrying-IP carrying-DTM carrying; When if desired the calling and called side all being carried out grappling, then calling procedure is changed into: A (caller visit CS territory)-A (caller ownership IMS territory)-B (called ownership CS territory)-B (called ownership IMS territory)-B (called visit CS territory), thus the mode of setting up of carrying in the call path is changed into: DTM carrying-IP carrying-DTM carrying-DTM carrying-IP carrying-DTM carrying.

Like this, for the calling in CS territory-CS territory, because the introducing of static anchor point scheme causes having inserted one or more snippets IP carrying route in simple DTM carrying route.When the DTM carrying converts the IP carrying to, need carry out the conversion of encoding and decoding speech, because the conversion of encoding and decoding speech can reduce the quality of speech business, the repeatedly encoding and decoding speech conversion that therefore static anchor point scheme is introduced can have a strong impact on original speech business quality.

In addition, calling for CS territory-CS territory, because the introducing of static anchor point scheme, cause in simple DTM carrying route, having inserted one or more snippets IP carrying route, because IP carrying can effectively utilize Internet resources, therefore can be further the routed path of session be optimized, prolong the IP bearer path of introducing as much as possible, reduce the DTM bearer path, to reach the purpose that reduces the network operation cost.

Summary of the invention

The objective of the invention is to, a kind of session route path control method and system are provided, realized that application server routes to the routed path control of the session in the IMS territory in the CS territory to needs; Change the encoding and decoding speech conversion times that causes by DTM carrying and IP carrying that the present invention can reduce between CS territory and the IMS territory, avoid the reduction of speech business quality; And, also can realize saving the DTM carrying by the present invention, improve the purpose of the utilance of IP carrying.

For achieving the above object, a kind of session route path control method provided by the invention, for the session that need route to circuit commutative field from the IMS territory, this method may further comprise the steps:

A, application server are determined the network entity in the IMS territory of described session correspondence;

B, application server provide network entity information in its described IMS territory of determining to S-CSCF, and by S-CSCF described session are routed to network entity in the described IMS territory;

Network entity in c, the described IMS territory routes to network entity in the circuit commutative field with described session.

Described circuit commutative field is: mobile network's circuit switching (CS) territory, or PSTN network.

Described step a specifically comprises: application server is determined the network entity in the IMS territory of described session correspondence according to predetermined carrying optimisation strategy.

The described calling that need route to circuit commutative field from the IMS territory comprises: called when the circuit commutative field user, and the Calling Side session of in the IMS territory, initiating, or need in the IMS territory, carry out the callee side initial call of the circuit commutative field of grappling process.

Predetermined carrying optimisation strategy is among the described step a: once the MGCF of route process was identical with this session;

And described step a specifically comprises: a1, application server obtain the MGCF of calling process when routing to the IMS territory from circuit commutative field of described session correspondence;

A2, application server are defined as this MGCF the network entity information in the IMS territory of described session correspondence.

Among the described step a1: the MGCF that calls out process when routing to the IMS territory from circuit commutative field is determined according to predetermined policy by application server.

Predetermined policy among the described step a1 comprises: predetermined routing policy nearby.

Described step a1 specifically comprises: a12, MGCF with its information-bearing in INVITE, and by S-CSCF with this transmission of messages to application server;

The session that a13, application server are defined as routing to the CS territory with the information of the MGCF that carries in the INVITE is the information of the MGCF of route process once.

Also comprise in the INVITE of described step a12: MGCF is the Call Reference Number of this session of sign of this session distribution.

Described step b specifically comprises:

Application server is according to described MGCF information structuring CSRN, and it is issued to S-CSCF;

S-CSCF routes to this MGCF according to the MGCF information among the described CSRN with described session.

Described CSRN comprises: MGCF routing iinformation and former called party information; Or

Described CSRN comprises: MGCF routing iinformation and former called party information and Call Reference Number.

Described step c also comprises:

MGCF obtains the Call Reference Number of the session that S-CSCF transmits, and when determining session that this session crosses for route once according to this Call Reference Number, control MGW does not carry out encoding and decoding conversion to the session that goes out to exhale and go into to exhale.

Predetermined carrying optimisation strategy is among the described step a: with the nearest MGCF of the current MSC of called subscriber;

And described step a specifically comprises: application server obtains called subscriber's current location information of the session that need route to mobile network circuit switching (CS) territory, and determines and the nearest MGCF information of the current VMSC of called subscriber according to this positional information.

Described step b specifically comprises: application server is according to described MGCF information structuring CSRN, and it is issued to S-CSCF;

When S-CSCF determines that according to MGCF information session needs that described needs route to circuit commutative field are striden IMS territory route,, route to described MGCF with BGCF, the BGCF on user visiting ground of this session by the IMS territory at its place.

Described step c specifically comprises:

The MGCF of the double GMSC of being obtains mobile network circuit switching (CS) territory called subscriber's routing iinformation from HLR, and this session is routed directly to the MSC at the current place of called subscriber according to described routing iinformation.

Predetermined carrying optimisation strategy among the described step a comprises: with this session once the MGCF of route process identical or with the nearest MGCF of the current MSC of called subscriber;

And described step a specifically comprises:

Application server is chosen a kind of predetermined carrying optimisation strategy according to pre-defined rule, and determines that according to the carrying optimisation strategy of choosing needs route to the network entity in the IMS territory of session correspondence of circuit commutative field.

The step that application server in the IMS territory among the described step a is chosen a kind of predetermined carrying optimisation strategy according to pre-defined rule specifically comprises:

Application server according to user preference setting choose a kind of predetermined carrying optimisation strategy; And/or

Application server is chosen a kind of predetermined carrying optimisation strategy according to the called subscriber in the positional information of circuit commutative field.

Described user preference is provided with specifically and comprises: when carrying IMRN in the INVITE that application server receives, choose and this session identical carrying optimisation strategy of MGCF of route process once;

When in the INVITE that application server receives, carrying Tel URI, choose carrying optimisation strategy with the nearest MGCF of the current MSC of called subscriber.

Described application server is: the application server that has the inter-domain routing function in the IMS territory.

The present invention also provides a kind of session routed path control system, comprising:

Be positioned at the network entity determination module of application server:, determine the network entity in the IMS territory of session correspondence for the session that need route to circuit commutative field from the IMS territory;

Be arranged in the IMS territory routing module in IMS territory: obtain the network entity information in the definite described IMS territory of network entity determination module, and the session that described needs route to circuit commutative field is routed to IMS territory network entity according to described network entity information;

Be arranged in the cross-domain routing module of IMS territory network entity: obtain the network entity information that need route to circuit commutative field, and the session that routing module in the described IMS territory is transmitted is routed to network entity in the circuit commutative field.

The cross-domain routing module that is arranged in the network entity in IMS territory further comprises:

IMS domain-functionalities submodule: receive the session that routing module is transmitted in the IMS territory, and it is routed to the circuit commutative field function sub-modules.

The circuit commutative field function sub-modules: the route to called subscriber in the circuit commutative field is analyzed, and will talk about the switching center that routes to the current place of called subscriber according to route analysis.(identical) with claims

Description by technique scheme as can be known, for the session that needs to route to the CS territory in the IMS territory, application server among the present invention can be controlled to the routed path in CS territory from the IMS territory above-mentioned session according to routed path demand for control concrete in the network, as for the session that routes to the IMS territory from the CS territory, when needing that route is gone back to the CS territory from the IMS territory again, application server can according to the carrying optimisation strategy with this session by its once the network entity route in the IMS territory crossed of route go back to the CS territory, and encoding and decoding speech conversion between DTM carrying and the IP carrying is not carried out in the two sections sessions of going into to exhale and go out to exhale that belong to same session by this network entity control in the IMS territory crossed of route once, eliminated the IP bearer path of introducing under the static anchor point scheme, effectively reduce the encoding and decoding speech conversion times that session is carried to the routing procedure of CS territory from CS territory to IMS territory again, avoided the reduction of speech business quality; And for example for the session that need from the IMS territory, route to the CS territory, application server can will be talked about according to the carrying optimisation strategy and route to the nearest MGCF of network entity in the distance C S territory, change session over to the CS territory nearby by this MGCF then, prolonged the IP bearer path in the IMS territory as much as possible, reduce the DTM bearer path, improved the utilance of IP carrying; When the present invention is applied to static anchor point scheme under the call continuity problem, the DTM carrying that causes in the static anchor point scheme and the encoding and decoding speech conversion times between the IP carrying can have effectively been reduced, reduced of the influence of static anchor point scheme to the speech business quality, and be optimized by routed path to session, prolong the IP bearer path of introducing as much as possible, reduce the DTM bearer path, increased the advantage of static anchor point scheme, improved the practicality of static anchor point scheme.

Description of drawings

Fig. 1 is the user in CS territory when making a call as caller, and the calling of using CAMEL mechanism to initiate in the CS territory is toggled to the flow chart that AS with DTF function carries out grappling;

Fig. 2 is that the user in CS territory does when called, uses CAMEL mechanism that the calling of Incoming is toggled to the flow chart that AS with DTF function carries out grappling in the CS territory;

Fig. 3 is that the user in CS territory does when called, uses signaling catching mechanism that the calling of Incoming is toggled to the flow chart that AS with DTF function carries out grappling in the CS territory;

Fig. 4 is the user of CS territory or PSTN network when being the caller user, and when the MSISDN user in the IMS territory was the called subscriber, the network based analysis to called number of CS territory or PSTN routed the call to the IMS territory and is toggled to the flow chart that anchor point AS carries out grappling;

Fig. 5 is a session routed path control system schematic diagram of the present invention.

Embodiment

When the session in the IMS territory need route to circuit commutative field, if application server can be according to the routed path of predetermined routing policy control session, just can realize different purposes to route optimization or carrying optimization, in the static anchor point scheme under the call continuity problem, if the MGCF in the IMS territory can route to circuit commutative field nearby with session, then can prolong as much as possible because the IP bearer path that static anchor point scheme is introduced, reduce the DTM bearer path, optimized the DTM bearer path of session; If can be with session from its IMS network entity route telegram in reply road switching domain of crossing of route once, then can eliminate the IP bearer path of introducing under the static anchor point scheme, effectively reduce the number of times of calling out from circuit commutative field to the IMS territory again the encoding and decoding conversion the circuit commutative field routing procedure.

Therefore, core of the present invention is: for the session that need route to circuit commutative field from the IMS territory, application server is determined the network entity in the IMS territory of the correspondence that this session need route to, application server provides network entity information in its described IMS territory of determining to S-CSCF, and described session being routed to network entity in the described IMS territory by S-CSCF, the network entity in the described IMS territory routes to network entity in the circuit commutative field with this session.

Based on core concept of the present invention technical scheme provided by the invention is further described below.

User for mobile network circuit switching (CS) territory does called, when calling routes to called subscriber's GMSC, GMSC uses the CAMEL mechanism of network controls or calling that signaling catching mechanism will be initiated to be toggled to have DRF the gsmSCF of (inter-domain routing function) or the route that SRF calls out to control, then, gsmSCF or SRF with DRF function generate a routing number IMRN who points to the AS with DTF function in the IMS territory according to certain routing policy, and use CAMLE connect operation or SRI-Ack message that IMRN is handed down to GMSC.Here, having the gsmSCF of DRF function or SRF can point to the AS with DTF function except needs guarantee the IMRN that distributes when distributing IMRN, need also to guarantee that GMSC can will call out the fixing MGCF that selects in the IMS territory according to the IMRN of its distribution, GMSC sends IAM message according to IMRN to this MGCF then, makes this calling route to the IMS territory.Follow-up MGCF is forwarded to the AS with DTF function according to IMRN with session via I-CSCF, after having called party information that the AS of DTF function receives and comprising the session of IMRN of DTF PSI information, grappling control is carried out in session, promptly trigger the B2BUA function, stop the session that AS receives, initiate a new session then at former called party information, the AS that promptly has the DTF function is by obtaining the S-CSCF information of called subscriber's side with the Sh interface of HSS, then, will talk about and route to S-CSCF, and will talk about by this S-CSCF and to route to former callee side.Here, when the AS with DTF function initiates a new session at former called party information, need carry out route analysis to former called party information by AS with DRF function, judge to need to talk about at AS and route to when continuing in the mobile network circuit switching (CS) territory with DRF function, AS with DRF function is based on the CSRN of former called party information structure Tel-URI form, and what have then that the AS of DTF function initiates is CSRN at the called party information Requested-URI in the new session of former called party information.Have CSRN that the AS of DRF function distributes need to guarantee the S-CSCF of called subscriber's side can speech channel by returning MGCF identical when routing the call to the IMS territory with GMSC use IMRN, then, MGCF routes the call to GMSC according to CSRN.When MGCF judges the calling that oneself receives is that the GMSC that receives of MGCF is to the IAM of its transmission message, the calling of sending with oneself is that MGCF is when the IAM message of GMSC transmission belongs to same calling, MGCF control this moment MGW does not carry out encoding and decoding conversion to the session of going into to exhale and going out to exhale, be the IAM message that MGCF sends for the GMSC that receives, control MGW does not convert its DTM carrying to the IP carrying, MGCF is for the IAM message of sending to GMSC, control MGW directly uses its DTM that had before received carrying, thereby in the speech business in the DTM carrying of GMSC that the speech business in the DTM carrying of MGW that makes that GMSC initiates can be routed to nondestructively that MGW initiates.

The IMRN that the gsmSCF of the above-mentioned DRF of having function or SRF distribute needs to guarantee that GMSC can fix selects the process of the MGCF in the IMS territory to realize by the formation of IMRN, formation as IMRN can be the mode of " route prefix+DTF PSI+ Call Reference Number ", can fixedly be addressed to the MGCF of some appointments in the IMS territory according to this route prefix GMSC.

The CSRN that the AS of the above-mentioned DRF of having function distributes needs to guarantee will speech channel can be realized by constituting of CSRN by the process of returning MGCF identical when routing the call to the IMS territory with GMSC use IMRN, formation as CSRN can be the mode of " route prefix+former called party information+Call Reference Number ", can fixedly be addressed to the MGCF of some appointments in the IMS territory according to this route prefix S-CSCF.

Above-mentioned MGCF judge the calling that oneself receives be the GMSC that receives of MGCF to the IAM of its transmission message, can be that Call Reference Number and called party information in the calling that it receives among the CSRN is that whether identical mode is judged for Call Reference Number among the IMRN by judging called party information in its calling of sending with calling that oneself the sends process that to be MGCF belong to same calling to the IAM message that GMSC sends.

Here, MGCF INVITE that also can be MGCF by the session that oneself is sent send to the AS with DTF function according to IMRN and the session that receives promptly have the method that INVITE that the AS of DTF function sends to MGCF according to CSRN judges and judge whether two sections sessions belong to same session.Same, can be that Call Reference Number and called party information in the session that MGCF receives among the IMRN is that whether identical mode is judged for Call Reference Number among the CSRN by judging called party information in the session that MGCF sends.

Whether identical mode determines whether two sections call/session belong to the same call/session except using the Call Reference Number judge among two sections Call Reference Number among the called party information IMRN in the call/session and the called party information CSRN, MGCF can also be by increasing relevant parameter in the session information that sends at oneself, and the AS with DTF function transmits the relevant parameter that MGCF increases in the new session of initiating, thereby MGCF judges by judging its session of sending mode that whether comprises identical relevant parameter information in its session that receives that neutralizes whether two sections sessions belong to same session.Can increase the Call Reference Number that self distributes in the calling/called information in the session that oneself sends as MGCF, this session is sent among the AS with DTF function by I-CSCF then, AS with DTF function triggers the B2BUA function, stop the session that AS receives, initiate a new session then at former called party information, comprise the Call Reference Number that MGCF distributes in the calling/called information in this new session equally, then this new session is forwarded to same MGCF via S-CSCF.Thereby MGCF judges whether identical mode judges whether these two sections sessions belong to same session for Call Reference Number in the calling/called information in Call Reference Number and the session that it receives in the calling/called information in its session of sending.Further, MGCF is when distributing Call Reference Number, can in Call Reference Number, comprise the some MGW information that GMSC selects when the IAM message that sends to MGCF, thereby when MGCF receives S-CSCF to the session of its transmission, according to call reference information, judge when MGCF judges the calling that oneself receives and belongs to same calling with the calling of oneself sending at MGCF, MGCF is further according to the MGW information in the Call Reference Number information, the control session is selected and the identical MGW of previous calling, and then MGCF controls this MGW encoding and decoding conversion is not carried out in the session of going into to exhale and going out to exhale.

Above-mentioned application server determines that the starting point of IMS territory network entity is to reduce the conversion times of encoding and decoding, to guarantee the quality of speech business, therefore need will carry out relatedly with go into IMS territory and two sections callings that go out the IMS territory under once calling out at MGCF, and and control MGW encoding and decoding conversion is not carried out in the session of going into to exhale and going out to exhale.

Application server determines that the starting point of IMS territory network entity can also be to shorten as much as possible the DTM carrying, has prolonged the IP carrying of using, and improves the utilance of IP carrying.Therefore, when the AS with DRF function judges calling need be when the IMS territory routes to circuit commutative field, the AS that then has the DRF function is when distributing CSRN, consider called current positional information at circuit commutative field, the CSRN that distributes can route to the session in IMS territory the nearest MGCF of VMSC at the current called current place of distance, make session can just far go out the IMS territory, subsequent voice calls continues between this MGCF and VMSC, prolonged the IP carrying of using, shortened the DTM carrying, improved the utilance of IP carrying, for operator has reduced the network operation cost.

The AS of the above-mentioned DRF of having function considers that when the CSRN that distributes the called subscriber can realize that to the process of the current login state of called subscriber's HLR inquiry called subscriber the AS that promptly has the DRF function sends ATI (Any TimeInterrogation inquires about at any time) to HLR and realizes by the AS with DRF function in the positional information in CS territory.Location Information information in the ATI Ack message that AS with DRF function returns according to HLR can be judged the positional information at the current place of user.

The CSRN that the above-mentioned AS with DRF function distributes can route to the session in IMS territory the nearest MGCF of VMSC at the current called current place of distance, the process that makes session can just far go out the IMS territory can realize by the formation of CSRN: the formation as CSRN can be the mode of " route prefix+former called party information+Call Reference Number ", with reference to the positional information in the current mobile network circuit switching (CS) of called subscriber territory, distribution can be addressed to the route prefix of the MGCF nearest apart from the VMSC in the current mobile network circuit switching (CS) of called subscriber territory to AS with DRF function when distributing CSRN.

When above-mentioned S-CSCF selects MGCF according to route prefix, when the MGCF that judges the needs route according to the route prefix of CRSN as S-CSCF does not belong to this IMS territory and is the IMS territory of user attaching, when roaming as the user, user attaching IMS territory can not cover the mobile network circuit switching (CS) territory of the current visit of user, then need stride the IMS territory this moment and carry out route, then S-CSCF selects the BGCF in this IMS territory, will talk about and route to BGCF, the BGCF in this territory routes the call to the BGCF in the IMS territory on user visiting ground according to route prefix, BGCF in the IMS territory on subsequent user visit ground is addressed to the MGCF in the IMS territory on the nearest user visiting ground of the current VMSC of distance users according to route prefix, route the call to this MGCF then, MGCF according to former called party information with the GMSC of call forward to mobile network circuit switching (CS) territory, the current place of called subscriber.

Here, MGCF is when receiving the session of S-CSCF or BGCF forwarding, need carry out called route analysis according to called party information, to call out after for fear of MGCF and to send the GMSC that the called subscriber belongs to mobile network circuit switching (CS) territory once again back to the analysis of called party information, here MGCF is after receiving the INVITE of S-CSCF/BGCF, MGCF needs the double GMSC that is, finish to HLR and mobile network circuit switching (CS) territory called subscriber is got roaming number operation and obtain user's MSRN, continue after will calling out the direct VMSC that routes to the current place of user from MGCF/GMSC according to MSRN.

Further, because a MGCF can control a plurality of MGW, MGCF is receiving S-CSCF or the INVITE of BGCF, when setting up the DTM carrying, can be according to the user's who obtains routing iinformation, promptly finish to HLR mobile network circuit switching (CS) territory called subscriber is got the MSRN that the roaming number operation obtains the current place of user by the double GMSC of being of MGCF, thereby judge the VMSC address information at the current place of called subscriber, the nearest MGW of this VMSC of MGCF selected distance sets up MGW and carries to the DTM between the VMSC, thereby make that the DTM carrying of setting up between VMSC and the MGW is the shortest, further optimized calling and carried by the DTM that mobile network circuit switching (CS) territory routes between the IMS territory.

Be that example is further described technical scheme provided by the invention with the callee side session that need in the IMS territory, carry out static grappling below.

When the present invention was applied to static anchor point scheme under the call continuity problem, application server of the present invention was the AS with inter-domain routing controlled function in the IMS territory, the AS that promptly has the DRF function.Network entity in the IMS territory is a plurality of MGCF that are in different region locations.

Be described in detail below in conjunction with accompanying drawing 2,4 pairs of multiple implementation methods of the present invention of accompanying drawing.

Accompanying drawing 2 is for the user in mobile network circuit switching (CS) territory does when called, DRF in the IMS territory adopts and this session identical carrying optimisation strategy of MGCF of route process once, and use CAMEL mechanism is toggled to the flow chart that AS with DTF function carries out grappling with the calling of Incoming in the mobile network circuit switching (CS) territory.

In this flow process, mainly at step 2-6 and step 2-10～step 2-13, the step of describing in other step and the background technology is basic identical for improvement of the present invention.

Generate a routing number IMRN who points to the AS in the IMS territory at step 2-6, gsmSCF with DRF function, make GMSC route the call on this DTF according to this routing number with DTF function.Wherein the formation of IMRN can be " route prefix+DTF PSI+ Call Reference Number ", here, route prefix is used for indicating GMSC can fixedly be addressed to some MGCF in IMS territory, DTF PSI is used for indicating and will calls out the AS that need be anchored on the some DTF of the having functions in IMS territory, and Call Reference Number is used for calling of unique identification.Further, in order to save the DTM carrying, the gsmSCF with DRF function can distribute the route prefix of the MGCF correspondence nearest apart from GMSC according to the address information of GMSC when distributing route prefix, makes GMSC to route to the IMS territory nearby with calling out.The gsmSCF that has the DRF function then is handed down to GMSC by CAMEL connect message with IMRN.

At step 2-10～step 2-13, have called party information that the AS of DTF function receives and comprise the session of IMRN of DTF PSI information after, grappling control is carried out in session, promptly trigger B2BUA (back-to-back user agent) function, stop the session that AS receives, initiate a new session then at former called party information, the AS that promptly has the DTF function is by obtaining the S-CSCF information of called subscriber's side with the Sh interface of HSS, then, will talk about and route to S-CSCF, and will talk about by this S-CSCF and to route to former callee side.Wherein the formation of CSRN can be " route prefix+former called party information+Call Reference Number ", here, route prefix is used to indicate S-CSCF can fixedly be addressed to some MGCF, DRF distributes with route prefix identical among the IMRN that distributes among the step 2-6, with guarantee S-CSCF can speech channel by returning the identical MGCF that GMSC routes the call among the step 2-6, former called party information is used to indicate will really call out the called party information that continue, and Call Reference Number is used for MGCF identification and receives which two sections callings (incoming call and outbound call) and belong to same calling.

Here, when the AS with DTF function initiates a new session at former called party information, need carry out route analysis to former called party information by AS with DRF function, judge to need to talk about at AS and route to when continuing in the mobile network circuit switching (CS) territory with DRF function, AS with DRF function is based on the CSRN of former called party information structure Tel-URI form, and what have then that the AS of DTF function initiates is CSRN at the called party information Requested-URI in the new session of former called party information.

Here, route the call in the process of former callee side at S-CSCF, when former called party information is the Tel-URI form, S-CSCF carries out ENUM DNS translation function, if original called party number can be converted to the SIPURI form, then follow-up calling route is carried out in the IMS territory, otherwise, S-CSCF routes the call to the BGCF in this IMS territory, will call out the GMSC that finally routes to mobile network circuit switching (CS) territory via MGCF by BGCF, and is by GMSC that call proceeding is extremely called at last.When the AS with DTF function enabled the B2BUA function, for the session that stops at DTF with in the new session of initiating of DTF, DTF controlled to switch between the territory that may initiate subsequent user all to its maintenance state.

MGCF is when receiving the session of S-CSCF or BGCF transmission, MGCF judges the IAM of the calling GMSC that promptly MGCF receives in the step 2-8 transmission that oneself receives according to the Call Reference Number MGCF among the called party information CSRN, the session that sends with MGCF is when MGCF will belong to same calling to the IAM that GMSC sends in this step, MGCF control this moment MGW does not carry out encoding and decoding conversion to the session of going into to exhale and going out to exhale, be the IAM message that MGCF sends for the GMSC that receives, control MGW does not convert its DTM carrying to the IP carrying, MGCF is for the IAM message of sending to GMSC, control MGW directly uses its DTM that had before received carrying, thereby in the speech business in the DTM carrying of GMSC that the speech business in the DTM carrying of MGW that makes that GMSC initiates can be routed to nondestructively that MGW initiates.

Accompanying drawing 3 is for the user in mobile network circuit switching (CS) territory does when called, DRF in the IMS territory adopts and this session identical carrying optimisation strategy of MGCF of route process once, and use signaling catching mechanism is toggled to the flow chart that AS with DTF function carries out grappling with the calling of Incoming in the mobile network circuit switching (CS) territory.

In this flow process, mainly at step 3-5 and step 3-9～step 3-12, the step of describing in other step and the background technology is basic identical for improvement of the present invention.

Generate a routing number IMRN who points to the AS in the IMS territory at step 3-5, SRF with DRF function, make GMSC route the call on this DTF according to this routing number with DTF function.Wherein the formation of IMRN can be " route prefix+DTF PSI+ Call Reference Number ", here, route prefix is used for indicating GMSC can fixedly be addressed to some MGCF in IMS territory, DTF PSI is used for indicating and will calls out the AS that need be anchored on the some DTF of the having functions in IMS territory, and Call Reference Number is used for calling of unique identification.Further, in order to save the DTM carrying, the SRF with DRF function can distribute the route prefix of the MGCF correspondence nearest apart from GMSC according to the address information of GMSC when distributing route prefix, makes GMSC to route to the IMS territory nearby with calling out.The function phase GMSC that has the SRF imitation HLR of DRF function then returns SRI-Ack message, in this SRI-Ack message IMRN is sent to GMSC as called routing iinformation.

At step 3-9～step 3-12, have called party information that the AS of DTF function receives and comprise the session of IMRN of DTF PSI information after, grappling control is carried out in session, promptly trigger B2BUA (back-to-back user agent) function, stop the session that AS receives, initiate a new session then at former called party information, the AS that promptly has the DTF function is by obtaining the S-CSCF information of called subscriber's side with the Sh interface of HSS, then, will talk about and route to S-CSCF, and will talk about by this S-CSCF and to route to former callee side.Wherein the formation of CSRN can be " route prefix+former called party information+Call Reference Number ", here, route prefix is used to indicate S-CSCF can fixedly be addressed to some MGCF, DRF distributes with identical route prefix among the IMRN that distributes in the step 6, with guarantee S-CSCF can speech channel by returning the identical MGCF that GMSC routes the call in the step 6, former called party information is used to indicate will really call out the called party information that continue, and Call Reference Number is used for MGCF identification and receives which two sections callings (incoming call and outbound call) and belong to same calling.

Here, when the AS with DTF function initiates a new session at former called party information, need carry out route analysis to former called party information by AS with DRF function, judge to need to talk about at AS and route to when continuing in the mobile network circuit switching (CS) territory with DRF function, AS with DRF function is based on the CSRN of former called party information structure Tel-URI form, and what have then that the AS of DTF function initiates is CSRN at the called party information Requested-URI in the new session of former called party information.

Here, route the call in the process of former callee side at S-CSCF, when former called party information is the Tel-URI form, S-CSCF carries out ENUM DNS translation function, if original called party number can be converted to the SIPURI form, then follow-up calling route is carried out in the IMS territory, otherwise, S-CSCF routes the call to the BGCF in this IMS territory, will call out the GMSC that finally routes to mobile network circuit switching (CS) territory via MGCF by BGCF, and is by GMSC that call proceeding is extremely called at last.When the AS with DTF function enabled the B2BUA function, for the session that stops at DTF with in the new session of initiating of DTF, DTF controlled to switch between the territory that may initiate subsequent user all to its maintenance state.

MGCF is when receiving the session of S-CSCF or BGCF transmission, MGCF judges the IAM of the calling GMSC that promptly MGCF receives in step 8 transmission that oneself receives according to the Call Reference Number MGCF among the called party information CSRN, the session that sends with MGCF is when MGCF will belong to same calling to the IAM that GMSC sends in this step, MGCF control this moment MGW does not carry out encoding and decoding conversion to the session of going into to exhale and going out to exhale, be the IAM message that MGCF sends for the GMSC that receives, control MGW does not convert its DTM carrying to the IP carrying, MGCF is for the IAM message of sending to GMSC, control MGW directly uses its DTM that had before received carrying, thereby in the speech business in the DTM carrying of GMSC that the speech business in the DTM carrying of MGW that makes that GMSC initiates can be routed to nondestructively that MGW initiates.

When accompanying drawing 4 is the caller user for the user of CS territory or PSTN network, DRF in the IMS territory adopts and this session identical carrying optimisation strategy of MGCF of route process once, and the MSISDN user in the IMS territory is the called subscriber, routes the call to the IMS territory and is toggled to the flow chart that AS carries out grappling according to the analysis to called number in CS territory or the PSTN network.

In this flow process, mainly at step 4-2 and step 4-7～step 4-9, the step of describing in other step and the background technology is basic identical for improvement of the present invention.

Convert MSISDN to Tel-URI at step 4-2, MGCF, and send INVITE to I-CSCF.MGCF is sending in the INVITE to I-CSCF, the form that constitutes " route prefix+called party information such as Tel-URI+ Call Reference Number " of its called party information Requested-URI, here, route prefix be used to indicate S-CSCF fixedly addressing return this MGCF, the Call Reference Number that MGCF distributes is used for MGCF identification, and to receive which two sections calling be that incoming call and outbound call belong to same calling, the MGW information of selecting when further, this Call Reference Number can also comprise the calling that CS territory or PSTN network initiate.

At step 4-7, have the AS of DRF function by called party information is carried out route analysis, judge to need to talk about at AS and route to when continuing in the mobile network circuit switching (CS) territory with DRF function, have the CSRN of the AS of DRF function, trigger the DTF function then based on former called party information structure Tel-URI form.Wherein, the formation of CSRN can be " route prefix+former called party information+Call Reference Number ", here, route prefix is used to indicate S-CSCF can fixedly be addressed to some MGCF, AS with DRF function distributes the identical route prefix that carries with MGCF among the step 4-2 in INVITE, with guarantee S-CSCF can speech channel by returning the identical MGCF that CS territory among the step 4-1 or PSTN network route the call to, former called party information is used to indicate and will really calls out the called party information that continue, Call Reference Number is used for MGCF identification, and to receive which two sections calling be that incoming call and outbound call belong to same calling, here, the AS with DRF function distributes the identical Call Reference Number that carries with MGCF in the step 2 in INVITE.

At step 4-8～4-9, have the session that the AS of DTF function receives the AS with DRF function and carry out grappling control, promptly trigger the B2BUA function, stop the session that AS receives, initiate a new session at former called party information then, the called party information Requested-URI in this new session is the CSRN with AS structure of DRF function.The AS that promptly has a DTF function then, will talk about and route to S-CSCF by obtain the S-CSCF information of called subscriber's side with the Sh interface of HSS, and will be talked about by this S-CSCF and to route to former callee side.

Here, will talk about in the process that routes to former callee side at S-CSCF, because the Requested-URI that has in the new session of initiating of the AS of DTF function is CSRN, can not convert thereof into SIP URI form after the S-CSCF process ENUM DNS translation function, therefore S-CSCF will talk about the BGCF that routes to this IMS territory, by BGCF session is forwarded to the GMSC that MGCF routes to mobile network circuit switching (CS) territory.MGCF is when being received in the session of BGCF or S-CSCF transmission, judge the IAM message that the session CS territory that promptly MGCF receives in step 4-1 that oneself receives or PSTN network send according to Call Reference Number MGCF, with the session that sends be that MGCF belongs to same calling to the IAM message that CS territory or PSTN network send in this step, MGCF control this moment MGW does not carry out encoding and decoding conversion to the session of going into to exhale and going out to exhale, be the IAM message that MGCF sends for the GMSC that receives, control MGW does not convert its DTM carrying to the IP carrying, MGCF is for the IAM message of sending to GMSC, control MGW directly uses its DTM that had before received carrying, thereby in the speech business in the DTM carrying of CS territory or PSTN network that the speech business in the DTM carrying of MGW that makes that CS territory or PSTN network initiate can be routed to nondestructively that MGW initiates.

When the AS with DTF function enabled the B2BUA function, for the session that stops at DTF with in the new session of initiating of DTF, DTF controlled to switch between the territory that may initiate subsequent user all to its maintenance state.

Accompanying drawing 2 is for the user in mobile network circuit switching (CS) territory does when called, DRF in the IMS territory adopts the carrying optimisation strategy with the nearest MGCF of the current MSC of called subscriber, and uses CAMEL mechanism that the calling of Incoming is toggled to the flow chart that AS with DTF function carries out grappling in the mobile network circuit switching (CS) territory.

In this flow process, mainly at step 2-10～step 2-13, the step of describing in other step and the background technology is basic identical for improvement of the present invention.

At step 2-10～step 2-13, have called party information that the AS of DTF function receives and comprise the session of IMRN of DTF PSI information after, grappling control is carried out in session, promptly trigger B2BUA (back-to-back user agent) function, stop the session that AS receives, initiate a new session then at former called party information, the AS that promptly has the DTF function is by obtaining the S-CSCF information of called subscriber's side with the Sh interface of HSS, then, will talk about and route to S-CSCF, and will talk about by this S-CSCF and to route to former callee side.Wherein the formation of CSRN can be " route prefix+former called party information+Call Reference Number ", and here, route prefix is used to indicate S-CSCF can fixedly be addressed to some MGCF.DRF is before distributing CSRN, can send ATI to HLR earlier, the login state in the current mobile network circuit switching (CS) of inquiring user territory, and the Location Information information in the ATI Ack message of returning according to HLR can judge the positional information at the current place of user, and DRF distributes the route prefix that can be addressed to the MGCF nearest apart from the VMSC in the current mobile network circuit switching (CS) of called subscriber territory then.

Here, when the AS with DTF function initiates a new session at former called party information, need carry out route analysis to former called party information by AS with DRF function, judge to need to talk about at AS and route to when continuing in the mobile network circuit switching (CS) territory with DRF function, AS with DRF function is based on the CSRN of former called party information structure Tel-URI form, and what have then that the AS of DTF function initiates is CSRN at the called party information Requested-URI in the new session of former called party information.

Here, route the call in the process of former callee side at S-CSCF, when former called party information is the Tel-URI form, S-CSCF carries out ENUM DNS translation function, if original called party number can be converted to the SIPURI form, then follow-up calling route is carried out in the IMS territory, otherwise, S-CSCF routes the call to the BGCF in this IMS territory, will call out the GMSC that finally routes to mobile network circuit switching (CS) territory via MGCF by BGCF, and is by GMSC that call proceeding is extremely called at last.At S-CSCF with call forward during to MGCF, when the MGCF that judges the needs route according to the route prefix of CRSN as S-CSCF does not belong to this IMS territory and is the IMS territory of user attaching, when roaming as the user, user attaching IMS territory can not cover the mobile network circuit switching (CS) territory of the current visit of user, then need stride the IMS territory this moment and carry out route, then S-CSCF selects the BGCF in this IMS territory, will talk about and route to BGCF, the BGCF in this territory routes the call to the BGCF in the IMS territory on user visiting ground according to route prefix, follow-up BGCF is addressed to the nearest MGCF of the current VMSC of distance users according to route prefix, routes the call to this MGCF then.The double GMSC entity of doing of this MGCF entity, the MGCF function in the entity sends IAM message to the GMSC of inside function.

When the AS with DTF function enabled the B2BUA function, for the session that stops at DTF with in the new session of initiating of DTF, DTF controlled to switch between the territory that may initiate subsequent user all to its maintenance state.

After GMSC function in step 2-14, MGCF/GSMC entity receives the incoming call IAM message of MGCF function, use the mode of intelligent network business or the MSISDN that other switch technology therefrom parses former called subscriber, GMSC sends SRI message based on the MSISDN that parses to HLR then.

Accompanying drawing 3 is for the user in mobile network circuit switching (CS) territory does when called, DRF in the IMS territory adopts the carrying optimisation strategy with the nearest MGCF of the current MSC of called subscriber, and uses signaling catching mechanism that the calling of Incoming is toggled to the flow chart that AS with DTF function carries out grappling in the mobile network circuit switching (CS) territory.

In this flow process, mainly at step 3-9～step 3-12 and step 3-14, the step of describing in other step and the background technology is basic identical for improvement of the present invention.

At step 3-9～step 3-12, have called party information that the AS of DTF function receives and comprise the session of IMRN of DTF PSI information after, grappling control is carried out in session, promptly trigger B2BUA (back-to-back user agent) function, stop the session that AS receives, initiate a new session then at former called party information, the AS that promptly has the DTF function is by obtaining the S-CSCF information of called subscriber's side with the Sh interface of HSS, then, will talk about and route to S-CSCF, and will talk about by this S-CSCF and to route to former callee side.Wherein the formation of CSRN can be " route prefix+former called party information+Call Reference Number ", and here, route prefix is used to indicate S-CSCF can fixedly be addressed to some MGCF.DRF is before distributing CSRN, can send ATI to HLR earlier, the login state in the current mobile network circuit switching (CS) of inquiring user territory, and the Location Information information in the ATI Ack message of returning according to HLR can judge the positional information at the current place of user, and DRF distributes the route prefix that can be addressed to the MGCF nearest apart from the VMSC in the current mobile network circuit switching (CS) of called subscriber territory then.

Here, when the AS with DTF function initiates a new session at former called party information, need carry out route analysis to former called party information by AS with DRF function, judge to need to talk about at AS and route to when continuing in the mobile network circuit switching (CS) territory with DRF function, AS with DRF function is based on the CSRN of former called party information structure Tel-URI form, and what have then that the AS of DTF function initiates is CSRN at the called party information Requested-URI in the new session of former called party information.

Here, route the call in the process of former callee side at S-CSCF, when former called party information is the Tel-URI form, S-CSCF carries out ENUM DNS translation function, if original called party number can be converted to the SIPURI form, then follow-up calling route is carried out in the IMS territory, otherwise, S-CSCF routes the call to the BGCF in this IMS territory, will call out the GMSC that finally routes to mobile network circuit switching (CS) territory via MGCF by BGCF, and is by GMSC that call proceeding is extremely called at last.At S-CSCF with call forward during to MGCF, when the MGCF that judges the needs route according to the route prefix of CRSN as S-CSCF does not belong to this IMS territory and is the IMS territory of user attaching, when roaming as the user, user attaching IMS territory can not cover the mobile network circuit switching (CS) territory of the current visit of user, then need stride the IMS territory this moment and carry out route, then S-CSCF selects the BGCF in this IMS territory, will talk about and route to BGCF, the BGCF in this territory routes the call to the BGCF in the IMS territory on user visiting ground according to route prefix, follow-up BGCF is addressed to the nearest MGCF of the current VMSC of distance users according to route prefix, routes the call to this MGCF then.The double GMSC entity of doing of this MGCF entity, the MGCF function in the entity sends IAM message to the GMSC of inside function.

When the AS with DTF function enabled the B2BUA function, for the session that stops at DTF with in the new session of initiating of DTF, DTF controlled to switch between the territory that may initiate subsequent user all to its maintenance state.

After GMSC function in step 3-14, MGCF/GSMC entity receives the incoming call IAM message of MGCF, can use certain switch technology therefrom to parse former called subscriber's MSISDN, then, after based on the MSISDN that parses called party information being analyzed, the GMSC function in the MGCF/GSMC entity sends SRI message to obtain called subscriber's routing iinformation to HLR.The SRF that this calling is had the DRF function equally tackles, SRF with DRF function judges this calling is handled, then this not being tackled the SRI that gets off analyzes, do not carry out corresponding intra domain routing policy control and treatment, directly transmit this SRI message, and the SRI-Ack forwards that the HLR that it receives is returned is to the MGCF/GSMC entity to HLR.GMSC function in the MGCF/GSMC entity continues route the call to called subscriber's visit VMSC according to the routing iinformation of the called subscriber among the SRI-Ack that receives after.

When accompanying drawing 4 is the caller user for the user of CS territory or PSTN network, DRF employing in the IMS territory and the carrying optimisation strategy of the nearest MGCF of the current VMSC of called subscriber, and the MSISDN user in the IMS territory is the called subscriber, routes the call to the IMS territory and is toggled to the flow chart that AS carries out grappling according to the analysis to called number in CS territory or the PSTN network.

In this flow process, mainly at step 4-6～step 4-9, the step of describing in other step and the background technology is basic identical for improvement of the present invention.

At step 4-6～step 4-9, have called party information that the AS of DTF function receives and comprise the session of IMRN of DTF PSI information after, grappling control is carried out in session, promptly trigger B2BUA (back-to-back user agent) function, stop the session that AS receives, initiate a new session then at former called party information, the AS that promptly has the DTF function is by obtaining the S-CSCF information of called subscriber's side with the Sh interface of HSS, then, will talk about and route to S-CSCF, and will talk about by this S-CSCF and to route to former callee side.Wherein the formation of CSRN can be " route prefix+former called party information+Call Reference Number ", and here, route prefix is used to indicate S-CSCF can fixedly be addressed to some MGCF.DRF is before distributing CSRN, can send ATI to HLR earlier, the login state in the current mobile network circuit switching (CS) of inquiring user territory, and the Location Information information in the ATI Ack message of returning according to HLR can judge the positional information at the current place of user, and DRF distributes the route prefix that can be addressed to the MGCF nearest apart from the VMSC in the current mobile network circuit switching (CS) of called subscriber territory then.

Here, when the AS with DTF function initiates a new session at former called party information, need carry out route analysis to former called party information by AS with DRF function, judge to need to talk about at AS and route to when continuing in the mobile network circuit switching (CS) territory with DRF function, AS with DRF function is based on the CSRN of former called party information structure Tel-URI form, and what have then that the AS of DTF function initiates is CSRN at the called party information Requested-URI in the new session of former called party information.

Here, route the call in the process of former callee side at S-CSCF, when former called party information is the Tel-URI form, S-CSCF carries out ENUM DNS translation function, if original called party number can be converted to the SIPURI form, then follow-up calling route is carried out in the IMS territory, otherwise, S-CSCF routes the call to the BGCF in this IMS territory, will call out the GMSC that finally routes to mobile network circuit switching (CS) territory via MGCF by BGCF, and is by GMSC that call proceeding is extremely called at last.At S-CSCF with call forward during to MGCF, when the MGCF that judges the needs route according to the route prefix of CRSN as S-CSCF does not belong to this IMS territory and is the IMS territory of user attaching, when roaming as the user, user attaching IMS territory can not cover the mobile network circuit switching (CS) territory of the current visit of user, then need stride the IMS territory this moment and carry out route, then S-CSCF selects the BGCF in this IMS territory, will talk about and route to BGCF, the BGCF in this territory routes the call to the BGCF in the IMS territory on user visiting ground according to route prefix, follow-up BGCF is addressed to the nearest MGCF of the current VMSC of distance users according to route prefix, route the call to this MGCF then, the double GMSC entity of doing of this MGCF entity, the MGCF function in the entity sends IAM message to the GMSC of inside function.

When the AS with DTF function enabled the B2BUA function, for the session that stops at DTF with in the new session of initiating of DTF, DTF controlled to switch between the territory that may initiate subsequent user all to its maintenance state.

After GMSC function in step 4-10, MGCF/GMSC entity receives the incoming call IAM message of MGCF function, use the mode of intelligent network business or the MSISDN that other switch technology therefrom parses former called subscriber, GMSC sends SRI message based on the MSISDN that parses to HLR then.

The foregoing description is to be described according to two different carrying optimisation strategy respectively, its emphasis difference, scheme one lays particular emphasis on the conversion times that reduces encoding and decoding speech, with the loss to voice quality of the IP bearer path that guarantees the quality of speech business, eliminated to introduce under the static anchor point scheme; Scheme two lays particular emphasis on the IP bearer path that prolongs session as much as possible, reduces the DTM bearer path, to improve the utilance of IP carrying, has reduced the operation cost of network.The present invention also can be used in combination above-mentioned two kinds of technical schemes, the AS that promptly has the DRF function is carrying out the branch timing of CSRN, can wait to determine that the CSRN of distribution will speech channel route to the MGCF that can just far go out the IMS territory by returning and go into IMS and to call out identical MGCF or will talk about according to the preference setting of operator, called current positional information in mobile network circuit switching (CS) territory.During such as the first string in using the present invention, need change MGCF, in order to reduce change to the existing network network element, the preference setting of operator can be: the mode that is used in combination of the solution of the present invention one and scheme two is: when the AS with DRF function judges Requested-URI in the INVITE that receives and is IMRN, adopt the present invention program one to carry out follow-up call treatment, the CSRN that promptly has the AS distribution of DRF function can speech channel enter the identical MGCF that the IMS territory is chosen by returning with calling, when DRF judges Requested-URI in the INVITE that receives and is Tel-URI, then adopt the present invention program two to carry out follow-up call treatment, the CSRN that promptly has the AS distribution of DRF function can talk about and route to the MGCF with the nearest IMS territory of the current VMSC of called subscriber.

Session routed path control system provided by the invention as shown in Figure 5.

Among Fig. 5, session routed path control system of the present invention comprises: routing module and cross-domain routing module in network entity determination module, the IMS territory.

For the session that need route to circuit commutative field from the IMS territory, the network entity determination module is mainly used in the network entity in the IMS territory of determining the session correspondence.The network entity determination module is arranged in the present invention's application server.The network entity determination module can adopt predetermined carrying optimisation strategy to determine network entity in the IMS territory, as adopt with this session carrying optimisation strategy that once MGCF of route process was identical, and nearest definite IMS territories such as MGCF of the current MSC of called subscriber in network entity, the description in specific implementation method such as the above-mentioned method.

Routing module is mainly used in the network entity information of obtaining in the definite IMS territory of network entity determination module in the IMS territory, and according to this network entity information the session that needs route to circuit commutative field is routed to IMS territory network entity.Routing module can be arranged in the S-CSCF in IMS territory in the IMS territory.The method that routing module obtains the network entity information in the IMS territory in the IMS territory has multiple, the description in the concrete as above-mentioned method.

Cross-domain routing module is mainly used in the network entity information that need route in the circuit commutative field of obtaining, and the session that routing module route in the IMS territory is next routes to network entity such as MSC in the circuit commutative field.The inter-domain routing module is arranged in the network entity in IMS territory, as MGCF.

When MGCF is double when being GMSC, the function of cross-domain routing module is finished by IMS domain-functionalities submodule and circuit commutative field function sub-modules.IMS domain-functionalities submodule receives the session that routing module is transmitted in the IMS territory, and it is routed to the circuit commutative field function sub-modules.Circuit commutative field function sub-modules: finish route analysis, and route the call to the switching center at the current place of user according to route analysis to called subscriber in the circuit commutative field.

Though described the present invention by embodiment, those of ordinary skills know, the present invention has many distortion and variation and do not break away from spirit of the present invention, and the claim of application documents of the present invention comprises these distortion and variation.

Claims (21)

1, a kind of session route path control method is characterized in that, for the session that need route to circuit commutative field from the IMS territory, this method may further comprise the steps:

A, application server are determined the network entity in the IMS territory of described session correspondence;

B, application server provide network entity information in its described IMS territory of determining to S-CSCF, and by S-CSCF described session are routed to network entity in the described IMS territory;

Network entity in c, the described IMS territory routes to network entity in the circuit commutative field with described session.

2, a kind of session route path control method as claimed in claim 1 is characterized in that described circuit commutative field is: mobile network's circuit switching (CS) territory, or PSTN network.

3, a kind of session route path control method as claimed in claim 2 is characterized in that described step a specifically comprises:

Application server is determined the network entity in the IMS territory of described session correspondence according to predetermined carrying optimisation strategy.

4, a kind of route path control method as claimed in claim 2, it is characterized in that, the described calling that need route to circuit commutative field from the IMS territory comprises: called when the circuit commutative field user, the Calling Side session of in the IMS territory, initiating, or need in the IMS territory, carry out the callee side initial call of the circuit commutative field of grappling process.

5, a kind of session route path control method as claimed in claim 3 is characterized in that, predetermined carrying optimisation strategy is among the described step a: once the MGCF of route process was identical with this session;

And described step a specifically comprises:

A1, application server obtain the MGCF of calling process when routing to the IMS territory from circuit commutative field of described session correspondence;

A2, application server are defined as this MGCF the network entity information in the IMS territory of described session correspondence.

6, a kind of session route path control method as claimed in claim 5 is characterized in that, among the described step a1: the MGCF that calls out process when routing to the IMS territory from circuit commutative field is determined according to predetermined policy by application server.

7, a kind of session route path control method as claimed in claim 6 is characterized in that the predetermined policy among the described step a1 comprises: predetermined routing policy nearby.

8, a kind of session route path control method as claimed in claim 5 is characterized in that described step a1 specifically comprises:

A12, MGCF with its information-bearing in INVITE, and by S-CSCF with this transmission of messages to application server;

The session that a13, application server are defined as routing to the CS territory with the information of the MGCF that carries in the INVITE is the information of the MGCF of route process once.

9, a kind of session route path control method as claimed in claim 8 is characterized in that, also comprises in the INVITE of described step a12: MGCF is the Call Reference Number of this session of sign of this session distribution.

10, as claim 6,7 or 8 described a kind of session route path control methods, it is characterized in that described step b specifically comprises:

Application server is according to described MGCF information structuring CSRN, and it is issued to S-CSCF;

S-CSCF routes to this MGCF according to the MGCF information among the described CSRN with described session.

11, a kind of session route path control method as claimed in claim 10 is characterized in that:

Described CSRN comprises: MGCF routing iinformation and former called party information; Or

Described CSRN comprises: MGCF routing iinformation and former called party information and Call Reference Number.

12, a kind of session route path control method as claimed in claim 11 is characterized in that described step c also comprises:

MGCF obtains the Call Reference Number of the session that S-CSCF transmits, and when determining session that this session crosses for route once according to this Call Reference Number, control MGW does not carry out encoding and decoding conversion to the session that goes out to exhale and go into to exhale.

13, a kind of session route path control method as claimed in claim 3 is characterized in that, predetermined carrying optimisation strategy is among the described step a: with the nearest MGCF of the current MSC of called subscriber;

And described step a specifically comprises:

Application server obtains called subscriber's current location information of the session that need route to mobile network circuit switching (CS) territory, and determines and the nearest MGCF information of the current VMSC of called subscriber according to this positional information.

14, a kind of session route path control method as claimed in claim 13 is characterized in that described step b specifically comprises:

Application server is according to described MGCF information structuring CSRN, and it is issued to S-CSCF;

When S-CSCF determines that according to MGCF information session needs that described needs route to circuit commutative field are striden IMS territory route,, route to described MGCF with BGCF, the BGCF on user visiting ground of this session by the IMS territory at its place.

15, a kind of session route path control method as claimed in claim 13 is characterized in that described step c specifically comprises:

The MGCF of the double GMSC of being obtains mobile network circuit switching (CS) territory called subscriber's routing iinformation from HLR, and this session is routed directly to the MSC at the current place of called subscriber according to described routing iinformation.

16, a kind of session route path control method as claimed in claim 3 is characterized in that, the predetermined carrying optimisation strategy among the described step a comprises: with this session once the MGCF of route process identical or with the nearest MGCF of the current MSC of called subscriber;

And described step a specifically comprises:

Application server is chosen a kind of predetermined carrying optimisation strategy according to pre-defined rule, and determines that according to the carrying optimisation strategy of choosing needs route to the network entity in the IMS territory of session correspondence of circuit commutative field.

17, a kind of session route path control method as claimed in claim 16 is characterized in that, the step that the application server in the IMS territory among the described step a is chosen a kind of predetermined carrying optimisation strategy according to pre-defined rule specifically comprises:

Application server according to user preference setting choose a kind of predetermined carrying optimisation strategy; And/or

Application server is chosen a kind of predetermined carrying optimisation strategy according to the called subscriber in the positional information of circuit commutative field.

18, a kind of session route path control method as claimed in claim 16 is characterized in that described user preference is provided with specifically and comprises:

When in the INVITE that application server receives, carrying IMRN, choose and this session identical carrying optimisation strategy of MGCF of route process once;

When in the INVITE that application server receives, carrying Tel URI, choose carrying optimisation strategy with the nearest MGCF of the current MSC of called subscriber.

19, a kind of session route path control method as claimed in claim 1 is characterized in that described application server is: the application server that has the inter-domain routing function in the IMS territory.

20, a kind of session routed path control system is characterized in that, comprising:

Be positioned at the network entity determination module of application server:, determine the network entity in the IMS territory of session correspondence for the session that need route to circuit commutative field from the IMS territory;

Be arranged in the IMS territory routing module in IMS territory: obtain the network entity information in the definite described IMS territory of network entity determination module, and the session that described needs route to circuit commutative field is routed to IMS territory network entity according to described network entity information;

Be arranged in the cross-domain routing module of IMS territory network entity: obtain the network entity information that need route to circuit commutative field, and the session that routing module in the described IMS territory is transmitted is routed to network entity in the circuit commutative field.

21, a kind of session routed path control system according to claim 20 is characterized in that the cross-domain routing module that is arranged in the network entity in IMS territory further comprises:

IMS domain-functionalities submodule: receive the session that routing module is transmitted in the IMS territory, and it is routed to the circuit commutative field function sub-modules.

The circuit commutative field function sub-modules: the route to called subscriber in the circuit commutative field is analyzed, and will talk about the switching center that routes to the current place of called subscriber according to route analysis.

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