CN101175329A

CN101175329A - Cross-grouping domain switching method, system and device based on IP multimedia subsystem

Info

Publication number: CN101175329A
Application number: CN200710167256.1A
Authority: CN
Inventors: 顾炯炯
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2007-11-02
Filing date: 2007-11-02
Publication date: 2008-05-07
Also published as: WO2009065334A1

Abstract

The present invention discloses a cross grouping domain switching method, system and equipment, which is based on an IP multimedia subsystem. With the present invention, a multi-mode terminal can carry out a complete IMS network registering process without being switched to a switching target grouping domain; so the speed of the cross grouping domain switching of a multimedia real-time conversation is effectively improved. In addition, during the switching process, the signaling flow transmitted between the terminal and the network can be transmitted without going through the S-CSCF and the SIP AS of an IMS core network; so the switching efficiency of the multimedia real-time conversation is enhanced.

Description

Cross-grouping domain switching method, system and equipment based on IP Multimedia System

Technical field

The present invention relates to communication technical field, particularly based on cross-grouping domain switching method, system and the equipment of IP Multimedia System (IMS).

Background technology

As not fixing, move the core net network architecture that merges the evolution developing goal, IMS core net (IMS Core) needs to support to be shared by multiple access technology simultaneously, must guarantee simultaneously to be independent of unified continuity and multimedia service experience fixing, mobile plurality of access modes for the terminal use provides.

Along with GPRS (GPRS, General Packet Radio Service), universal mobile telecommunications system (UMTS, Universal Mobile Telecommunication System), code division multiple access (CDMA, Code Division Multiple Access), Wireless Fidelity (WiFi, WirelessFidelity), micro-wave access global inter communication (WiMAX, Worldwide Interoperability forMicrowave Access) etc. polytype wireless data access network technology is surging forward and develops, the multimode terminal of customer-centric is (as GSM/WiFi, WiMax/WiFi UMTS/CDMA) will progressively obtain to popularize in daily communication applications.Pass through multimode terminal, the user is no longer necessary for independently terminal of every class access technology application, and can in the roaming moving process, visit multiple different access technology with terminal adaptively by single user ID, and enjoy seamless continuous multimedia service and experience.Therefore handoff procedure how to guarantee the multimedia service session is realized the general ambulant demand of the technology that spans into to user transparent, is the key subject that the IMS network must solve, and also is that the IMS network is different from one of most important characteristic of traditional soft switching network.

At WiFi/EVDO (EVDO, Evolution Data Only, data transfer optimization) phone service continuity between grouping access and UMTS/GSM/CDMA circuit domain honeycomb cover, 3GPP, 3GPP2 normal structure have proposed continuous voice call (VCC based on IMS at Release 7, VoiceCall Continuity) solution, substantially, freeze before this standard mesh, can support ripe commercial deployment.And span into switching between the technology at packet domain, the ietf standard group has proposed the solution of mobile IP previously, but at striding the exigent multimedia service continuity of real-time, the delay performance of common mobile IP mechanism temporarily also can't reach other requirement of bussiness class at present; The 3GPP standard group has also started the research project that is intended to solve multimedia service continuity (MSC) problem at Release 8 in the near future simultaneously, the base mechanisms and the VCC of this solution are similar, select and cross-domain switching problem based on the territory of MSC application server (MSCAS) control solution IMS Multimedia session between the different grouping access network of service application layer.Following mask body is introduced the method that two kinds of existing solution cross-grouping domains are realized switching.

Prior art one: based on the MSC of 3GPP definition.

In view of VCC has only solved the problem that voice switch, 3GPP is in Release 8 standards, further propose the Multimedia session handover scheme and solved the problem that cross-grouping domain switches, its implementation and VCC are similar, all be after the purpose network that switches is registered, initiate handoff request to AS, finish switching by AS control.

Fig. 1 is the MSC handover network Organization Chart of existing 3GPP definition.

Packet domain 1 and packet domain 2: can be packet domain access network arbitrarily, as WiFi/WiMAX, GPRS/UMTS/HSPA, CDMA/EVDO etc.

MSC AS: realize change detection and switching controls, territory selection function, subscribe to by the mutual information between Ut support and the UE; The information of transmitting comprises that VCC switches the territory selection strategy of unified resource sign (VDI, VCC Domain Transfer URI) and operator, and described territory selection strategy can be that preferably which carries out session etc. when online when being in a plurality of packet domain.

HSS: home subscriber server, be used for store M SC user's triggering rule (iFC), calling can be triggered to MSC AS.When this user does caller, this iFC is configured to first trigger point; When the user does this iFC to be configured to last trigger point when called.

S-CSCF: service call conversation control function is triggered to MSC AS according to the iFC data with calling.

P-CSCF: Proxy Call Session Control Function is used for being connected between packet domain and the S-CSCF.

Behind the signatory cross-grouping domain service switchover of user, HSS can generate the iFC that relative trigger is called out MSCAS, when this user does caller, this iFC is configured to first trigger point; When the user does this iFC to be configured to last trigger point when called.When the user makes a call or has when calling out incoming call, S-CSCF triggers according to iFC and calls out corresponding M SC AS so that the control that MSC AS obtains calling out, and MSC AS can determine whether this user of grappling according to the grappling strategy of customer service configuration.

When terminal is carried out cross-grouping domain when switching according to network coverage condition monitoring to needs, the identification log that terminal can insert in new packet domain, obtain the IP address after, register to the IMS territory again.After succeeding in registration in the IMS territory, promptly initiate SIP INVITE request, in signaling, carry and switch indication (for example VDI that obtains from network side or other values of configuration).After MSC AS receives the INVITE request, analyze signaling and identify the switching indication, carry out handover operation, initiate ReINVITE message, carry out the negotiation of medium again with newly-established calling to original conversation side.Behind new call setup, MSC AS removes old calling immediately.

Figure 2 shows that the flow chart of the cross-grouping domain switching of an embodiment of the prior art.P-CSCF1 and P-CSCF2 are respectively and are arranged in packet domain 1 and packet domain 2 in the present embodiment.UE1 and UE2 are in the communication process, and UE1 is current is in the packet domain 1.

Step 1, UE1 monitoring network coverage condition, 2 switching is initiated from packet domain 1 to packet domain in decision, and UE1 finishes access registration by packet domain 2, the basic operation that is used to insert with finish that IP network layer adheres to and authentication etc.And UE1 finishes the registration of IMS territory with new user identity in packet domain 2, promptly carries out registration, the authentication operations of application layer with new user identity.

Because UE1 registers with new user identity, therefore, the public user identity (IMPU) that uses when the IMPU of use is with registration in packet domain 1 during its registration is different.

Step 2a-3b, UE1 initiates SIP call request (INVITE) after the registration of IMS territory is finished, carry in this request to switch and indicate for example VDI.

Step 4-5, the S-CSCF in the IMS core net is triggered to MSC AS according to the signatory attribute of user's MSC with calling, makes MSC AS can intercept and capture the SIP conversation control power.

Step 6-7, MSC AS preserves UE1 at related between packet domain 1 employed public user identity of packet domain 2 employed public user identity and this UE1, and, MSC AS is according to switching indication, carry out cross-grouping domain and switch, initiate ReINVITE message to the UE2 of opposite side by the IMS core net.

Step 8-14g, UE2 and UE1 finish the media negotiation of new calling by IMS core net and MAC AS.

Step 15-22 sets up new calling by IMS core net and MAC AS between UE1 and the UE2.

Step 23, UE1 and UE2 are in the enterprising guild of newly-established calling words.

Step 24-27, MSC AS is the connection release of packet domain 1 in original packet domain with UE1.

In above-mentioned implementation, there is following problem at least:

1) because 3GPP MSC is based on the continuity of VCC scheme, therefore, at every turn before carrying out SIP application layer handover operation, except that needs UE finish that IP network layer adheres to and authentication process, also need registration, authentication that UE initiates the SIP application layer again to realize user's related at target network IP address and public user identity (IMPU), meanwhile, CSCF also needs to finish the IMS user contracting data download from HSS, cause hand off signaling face time delay big, reduced the continuity of business experience.

2) referring to step 8-22 as can be known, all service switchover streams all need to pass through P-CSCF and S-CSCF under this scheme, carry out further having increased the signaling plane handover delay alternately between MSC AS and terminal.

3) since terminal detecting new targeted packets territory network signal and initiating SIP when registration, current already present SIP session can't discharge, thereby determined dual-mode terminal must adopt other IMPU to initiate registration, and realize related between the original public user identity of this public user identity and user at MSCAS.

4) the Multimedia session handoff procedure depends on the control that MSC AS intercepts and captures the SIP session, and handoff procedure is carried out Decision Control, and MSC AS need realize integrated with other value-added services SIP AS by the iFC triggering rule chain of serial arrangement according to priority.If other with the SIP AS of user service models (B2BUA) mode work back-to-back can not transparent transmission from the ReINVITE message of MSC AS, then will cause handoff failure; Therefore the integrated restriction that will be subjected to other AS message transmission capacities to a certain extent of success of this handover scheme and other value-added services AS.

Prior art two: based on the mobile IP scenario of IETF:

Figure 3 shows that mobile IP wallchart based on prior art.It comprises:

HA: home agent, refer to a main frame or a router that is connected to the mobile node local network, it preserves the positional information of mobile node, the packet that mails to mobile node can be passed to mobile node when mobile node leaves local network.

FA: Foreign Agent, refer to main frame or router on the field network at the place that mobile node is current, it can be transmitted to mobile node to the packet of being sent here by local agent.

MN: mobile node is a main frame or router, and every MN has two addresses: local address and outer way address (CoA).Local address is meant permanent this address of node of distributing to, and when MN was mobile on Internet, its local address was constant; CoA is the outlet that connects the tunnel of HA and MN, and when handoff links, the CoA address also changes thereupon.

The operation flow of mobile IP is summarized as follows:

In mobile IP protocol, each mobile node all has a unique local address, and its local address is constant when mobile node moves.When mobile node was connected on the field network link, outer way address just was used for identifying the present residing position of mobile node, so that carry out Route Selection.Uniting of the local address of mobile node and current outer way address is known as mobility binding.

When mobile node obtains a new outer way address, register to local agent by binding, so that allow local agent in time understand the current location of mobile node.When mobile node was connected on the local network link, the working mechanism of mobile node was the same with stationary nodes, did not use mobile IP function.When mobile node is to the field network link, it generally uses rules that are called " agent discovery " to find a Foreign Agent on foreign link, and register to this Foreign Agent, the outer way address of the IP address of this Foreign Agent as oneself.Mobile node is told local agent the outer way address of oneself by the registration rules after obtaining outer way address by said method again.When mailing to the packet of mobile node local address, local agent just intercepts this packet like this, and according to the outer way address of registering, sends packet to mobile node by tunnel (local agent is to outer way address).But by the packet that mobile node sends is directly to be routed on the destination node, need not tunneling technique.

There is following problem at least in the scheme of above-mentioned mobile IP:

1) triangle route.The local agent of mobile node, home agent, the triangle route that forms between Foreign Agent might increase transmission delay, influences audio frequency, real time business such as video.In addition, packet hop count in network is too much, can waste Internet resources, increases network load, for the enforcement generation adverse influence of multimedia service.

2) multimode terminal is in the registration handoff procedure of mobile IP, do not keep the two-way Media Stream of source and destination to connect from handover source packet domain access network to the process of switching target packet domain access network simultaneously, but adopt home agent outwards to act on behalf of the mode of transmitting packet by the tunnel, make the user's face Media Stream that switches to obtain the continuity guarantee, according to actual measurement, this time delay is the longest will to reach 6-7 second, can't satisfy real time multimedia sessions and switch the requirement that requires to be lower than 200ms.

3) if adopt the mode of mobile IP, then grouping cut-in convergent node (as GGSN, ASN-GW etc.) and user terminal all there are certain requirement, and require to dispose HA, at present can commercial preparation immature relatively, and the networking cost is also higher.

Summary of the invention

The embodiment of the invention is to provide a kind of cross-grouping domain switching method based on IP Multimedia System, system and equipment, that can realize IMS real-time multimedia business carries out the cross-grouping domain seamless switching, shorten hand off signaling face time delay, improve the continuity of business experience.

The technical scheme of the embodiment of the invention comprises:

A kind of cross-grouping domain switching method based on IP Multimedia System, first terminal are successfully set up Media Stream and are connected; The Proxy Call Session Control Function P-CSCF that moves to the handover source packet domain of switching purpose packet domain and described first terminal when first terminal from the handover source packet domain and the P-CSCF that switches the purpose packet domain not simultaneously, this method also comprises:

The P-CSCF of described handover source packet domain receives the handoff request of adaptive switched purpose packet domain P-CSCF, connect with the P-CSCF of described switching purpose packet domain, realize that first terminal is by P-CSCF, the P-CSCF of handover source packet domain of switching purpose packet domain and the Signalling exchange of network side;

Described first terminal realizes that by switching back packet domain and the new media bearer of called foundation cross-grouping domain switches.

A kind of cross-grouping domain switching method based on IP Multimedia System, first terminal are successfully set up Media Stream and are connected; When the P-CSCF that moves to the handover source packet domain of switching purpose packet domain and described first terminal from the handover source packet domain when first terminal was same P-CSCF with the P-CSCF that switches the purpose packet domain, this method also comprised:

After described P-CSCF received handoff request, control was switched the purpose network side for the medium reservation resource after switching, and makes the terminal of winning carry out Signalling exchange by described P-CSCF and network side;

A kind of cross-grouping domain switched system based on IP Multimedia System comprises and sets up first terminal that Media Stream connects that the P-CSCF of the handover source packet domain of described first terminal is connected controlled entity with the P-CSCF and the medium that switch the purpose packet domain,

The P-CSCF of described handover source packet domain is used to receive handoff request, connects with the P-CSCF of described switching purpose packet domain, make the terminal of winning by switching the purpose packet domain P-CSCF, the P-CSCF of handover source packet domain and the Signalling exchange of network side; Connect controlled entity by medium and carry out the media resource control operation;

Described first terminal is used for realizing that by switching back packet domain and the new media bearer of called foundation cross-grouping domain switches.

A kind of cross-grouping domain switched system based on IP Multimedia System comprises and sets up first terminal that Media Stream connects, is the handover source packet domain of described first terminal and the P-CSCF of switching purpose packet domain service simultaneously, and medium connection controlled entity,

Described P-CSCF is used to receive handoff request, and control is switched the purpose network side for the medium reservation resource after switching, and makes the terminal of winning carry out Signalling exchange by cutting described P-CSCF and network side; Connect controlled entity by medium and carry out the media resource control operation;

A kind of Proxy Call Session Control Function P-CSCF serves the first terminal handover source packet domain, comprising:

Signaling control unit is used to receive handoff request, connects with the P-CSCF that switches in the destination packet domain, makes the terminal of winning realize Signalling exchange by the P-CSCF that switches the purpose packet domain, the P-CSCF and the network side of handover source packet domain;

The media bearer control unit is used to control medium connection controlled entity and carries out the media resource control operation.

A kind of Proxy Call Session Control Function P-CSCF serves first terminal and switches the purpose packet domain, comprising:

The handover trigger unit receives the initiation handoff request from first terminal, sends to the P-CSCF of handover source packet domain;

The media bearer control unit is used for the interior medium connection of control switching purpose packet domain controlled entity and carries out resource reservation.

Use the present invention, make multimode terminal make that multimode terminal need not to carry out complete IMS network registry flow process once more after switching to switching purpose packet domain, the speed that switch in the territory is cut in the grouping of striding that has effectively promoted the multimedia real-time session.And in handoff procedure, interactive signaling stream does not need S-CSCF and the SIP AS through the IMS core net between terminal and the network, has promoted the switching efficiency of multimedia real-time session.

Description of drawings

Fig. 1 is the MSC handover network Organization Chart of existing 3GPP definition;

Figure 2 shows that the flow chart of the cross-grouping domain switching of an embodiment of the prior art;

Figure 3 shows that mobile IP wallchart based on prior art;

Figure 4 shows that according to the terminal of the embodiment of the invention one and switch schematic diagram from the cross-grouping domain that different P-CSCF insert;

Figure 5 shows that based on signaling process figure embodiment illustrated in fig. 4;

Figure 6 shows that the Security Association of setting up by tunnel style according in the IMS handoff procedure of the embodiment of the invention (SA);

Figure 7 shows that the cross-grouping domain hand off signaling flow chart that inserts from same P-CSCF according to the terminal of the embodiment of the invention one;

Figure 8 shows that according to the terminal of the embodiment of the invention two and switch schematic diagram from the cross-grouping domain that different P-CSCF insert;

Figure 9 shows that based on signaling process figure embodiment illustrated in fig. 8;

Figure 10 shows that the cross-grouping domain hand off signaling flow chart that inserts from same P-CSCF according to the terminal of the embodiment of the invention two.

Embodiment

Below in conjunction with drawings and the specific embodiments the present invention is described in further details again.

At first, the definition that the IMS session cross-grouping domain of the embodiment of the invention is switched describes: the Multimedia session of supposing IMS terminal 1 is carrying out in the process, IMS terminal 1 originally inserted IMS by packet domain access network 1, its service cut-in convergent node is node 1 (Node1), after IMS terminal 1 moves to another packet domain access network 2 from 1 roaming of packet domain access network, its service cut-in convergent node 2 (Node2) are different from cut-in convergent node 1, and wish to keep the unbroken continuity of current ongoing IMS session in this process, then no matter packet domain access network 1 whether access style is identical with packet domain access network 2, all claim this IMS terminal 1 that the switching of " cross-grouping domain " has taken place, wherein packet domain access network 1 is called as " handover source packet domain ", and packet domain access network 2 is called as " switching the purpose packet domain ".

Above-mentioned packet domain access network 1 and packet domain access network 2 can be one of mobile grouping broadband access methods of any type, as WiFi/WiMAX, GPRS/UMTS/HSPA, CDMA/EVDO etc.

The embodiment of the invention provides a kind of cross-grouping domain switching method based on IP Multimedia System: comprising: set up Media Stream and be connected between first terminal and second terminal, described first terminal re-registers to be switched in the destination packet domain, and the P-CSCF in Proxy Call Session Control Function P-CSCF in the switching source packet domain of described first terminal and the switching destination packet domain is not simultaneously, after P-CSCF in the described switching source packet domain receives handoff request, connect with the P-CSCF in the described switching destination packet domain, control described first terminal and switch destination by the P-CSCF in the described switching destination packet domain, switch the session of setting up of interior P-CSCF of source packet domain and described second terminal, realize Signalling exchange; P-CSCF in the described switching source packet domain controls described first terminal and sets up new media bearer by switching between back packet domain and described second terminal, realizes that cross-grouping domain switches.

The embodiment of the invention also provides a kind of cross-grouping domain switching method based on IP Multimedia System, has set up Media Stream and be connected between first terminal and second terminal; Described first terminal re-registers to be switched in the destination packet domain, and the P-CSCF in the switching source packet domain of described first terminal is when to switch P-CSCF in the destination packet domain be same P-CSCF, after described P-CSCF receives handoff request, set up described first terminal and switch the session of destination and described second terminal, the interactive information of transparent transmission terminal and network side realizes Signalling exchange; Described P-CSCF controls described first terminal and sets up new media bearer by switching between back packet domain and described second terminal, realizes that cross-grouping domain switches.

Embodiment one: the packet domain access network that switches source has been disposed Session Border Controller (SBC, Session Border Controller), telecommunications and the Internet converged services and high-level network (TISPAN are adopted in Access Network carrying control, TelecommunicationsandInternetConverged Services andProtocols for Advanced Networking) strategy decisive function based on business (SPDF) model of protocol definition, to be P-CSCF by SPDF control SBC finish contains network address translation (nat) and passes through, service quality (QOS) management and security control are in interior bearing bed resource control, and all Media Streams of user conversation all can pass through this SBC.

Specific implementation one: the terminal that the cross-grouping domain switching takes place inserts from different P-CSCF.

Figure 4 shows that according to the terminal of the embodiment of the invention one and switch schematic diagram from the cross-grouping domain that different P-CSCF insert.Terminal 1 is that the handover source packet domain roams into packet domain access network 2 and promptly switches the purpose packet domain from packet domain access network 1 in this example, and former Media Stream is represented in the single-point setting-out among the figure, and two-dot chain line represents to switch the newly-built Media Stream in back, and black solid line is represented session signaling.The implementation procedure that cross-grouping domain switches is as follows:

1) terminal 1 is finished the authentication process of Access Network at the cut-in convergent node (P-CSCF2) that switches the purpose packet domain, obtains in the IP address of switching the purpose packet domain and the address of P-CSCF2 entrance.

2) terminal 1 directly sends and initiates handoff request message to P-CSCF2, start handoff procedure with request, the RequestURI of this message fills in the address of P-CSCF1, mainly carries cell in the message and comprises: the Session Description Protocol (SDP) after handoff request indication, the switching, user ID etc.Wherein, describe source IP address, the port of user media stream among the SDP, target ip address, port reach information such as medium type.

If between terminal 1 and the P-CSCF1 based on the Authentication and Key Agreement (AKA of IMS, Authentication and Key Agreement) agreement or other authentication patterns have been set up IPSec SA (IPSec, Internet Protocol Security, IP security protocol; SA, Security Association), then user ID, the handoff request indication of terminal 1 in the initiation handoff request message that P-CSCF2 sends do not done encryption as expressly sending, and other parts then are included in the encrypted tunnel.This SA tunnel is two-way, and the message of tunnel encapsulation is the message that is subjected between the terminal 1 to P-CSCF1 of ipsec protection.

If do not set up IPSec SA between terminal 1 and P-CSCF1 originally, then terminal 1 directly sends with clear-text way to the initiation handoff request message that P-CSCF2 sends, and need P-CSCF2 that the legitimacy of user's handoff request is authenticated this moment.

Wherein, transmission, receiving port and the former P-CSCF1 of the IP head that encapsulates in the interacting message between P-CSCF2 and the terminal 1 and the SA between the terminal 1 keep independent.

3) after P-CSCF2 receives the initiation handoff request message of self terminal 1, by the expressly user ID and the switching indication of part, learn that switching has taken place terminal 1, subsequently P-CSCF2 further send handoff request message to P-CSCF1 to ask for the safe context data between P-CSCF1 and the terminal 1.

4) P-CSCF1 obtains user's safe context data according to user IMPU, sends to P-CSCF2, and these safe context data can comprise the parameter of setting up SA between P-CSCF1 and the terminal 1, and/or authentication parameter.

If set up IPSec SA between terminal 1 and P-CSCF1, then P-CSCF1 sends to P-CSCF2 with the parameter of setting up SA between P-CSCF1 and the terminal 1 by the session of having set up, and P-CSCF1 sends charge information to Charging Collection Function (CCF).

If do not set up IPSec SA between terminal 1 and P-CSCF1 originally, then P-CSCF1 sends to P-CSCF2 with authentication parameter by the session of having set up, and P-CSCF1 sends charge information to CCF.

5), then the message content of IPSec ESP encapsulation is carried out integrity verification and encrypted payload deciphering based on the parameter of IPSec SA if P-CSCF2 has obtained to be used to set up the parameter of SA;

If P-CSCF2 does not obtain the parameter of IPSec SA then based on authentication parameter handoff request message is carried out authentication, the standard authentication process of the relative IMS of authentication has here been omitted the process that HSS reaches authorization data, shortened the signaling plane time delay, the IMS standard authentication process speed of prior art wants fast relatively.

If integrity verification and successful decryption, or message authentication success then continue next step flow process, otherwise return the handoff failure response to terminal 1.

6) P-CSCF2 sends a message to SPDF2 according to the later initiation handoff request information of decoding, the application reserved resource, and further passing through H.248 by SPDF2, interface control SBC2 sets up switching destination user terminal address to the medium connection of switching destination SBC2.

7) P-CSCF2 initiates formal handoff request to P-CSCF1.

8) after P-CSCF1 receives formal handoff request, send a message to SPDF1, by SPDF1 by the control of agreement H.248 SBC1 Media Stream must alter course, adaptive and code conversion.Can also further send event charging information, carry and switch sign to CCF.

9) P-CSCF1, finishes by switching to the P-CSCF2 indication to remove the former session connection between self and the terminal 1 simultaneously to 1 message of terminal.

10) P-CSCF2 sends handoff completion message to terminal 1, and the indication handoff procedure is finished.Send charge information to CCF, carry and switch sign.

Behind handover success, P-CSCF2 will and P-CSCF1 between transmit interaction message such as Update between all terminals and the network, Reinvite, Info etc. on the switching session of having set up, up to the end side conversation end, end session again between P-CSCF2 and the P-CSCF1.Also promptly, for signaling plane, terminal 1 is mutual by P-CSCF2-＞P-CSCF1 and network side; For the medium face, terminal 1 is that terminal 2 is carried out alternately by SBC2-＞SBC1 and opposite end.

Figure 5 shows that based on signaling process figure embodiment illustrated in fig. 4.Terminal 1 and terminal 2 are being conversed, and terminal 1 desire is that packet domain access network 1 switches to that to switch the purpose packet domain be packet domain access network 2 from the handover source packet domain, inserts the IMS network by switching the purpose packet domain.

Step 1, terminal 1 detects network signal intensity, and decision is attached to the cut-in convergent node Node2 that switches the purpose packet domain again from the current cut-in convergent node Node1 of handover source packet domain.Terminal 1 is finished the authentication process of Access Network in the network of packet domain access network 2, obtain the address of IP address and P-CSCF2 by dynamic host allocation protocol (DHCP, Dynamic Host Configuration Protocol).

Step 2, terminal 1 sends Invite and initiates handoff request message to P-CSCF2, P-CSCF2 initiates handoff request with notice, the RequestURI of this message fills in the address of P-CSCF1, carry handoff request in the message, information such as the SDP after switching and user ID, this user ID can be IP multimedia pUblic identity (IMPI) or IP multimedia private identity (IMPU).

If between terminal 1 and the P-CSCF1 AKA agreement or other authentication patterns based on IMS set up IPSec SA, then terminal 1 will be encrypted based on this SA except that the information user IMPU, the handoff request indication, and send to P-CSCF2 with plaintext cell mutual encapsulation such as user IMPU, safe context request indications in Invite message body.Wherein, the IP hair that encapsulates in the interactive messages between P-CSCF2 and the terminal 1 send the SA between receiving port and former P-CSCF1 and the terminal 1 to keep independent.This SA tunnel is two-way, and the message of tunnel encapsulation is the message that is subjected between the terminal 1 to P-CSCF1 of ipsec protection, and its tunnel style as shown in Figure 6.No background color is partly represented expressly part among Fig. 6; The part that has background color represents to be subjected to IPSec ESP encryption/integrity protection part.

If do not set up IPSec SA between terminal 1 and P-CSCF1 originally, then terminal 1 directly sends with clear-text way to the Invite message that P-CSCF2 sends, and needs this moment P-CSCF2 that the legitimacy of the Invite message of coming self terminal is authenticated.

Step 3, P-CSCF2 sends Invite message to P-CSCF1, carries in the message and asks for safe context request and user IMPU sign.

Step 4, P-CSCF1 indicates the safe context data that obtain this terminal from this locality according to IMPU and the safe context request of user in the Invite message, sends to P-CSCF2 by Info or 183 message.

Step 5, if this terminal has been set up SA before switching, then P-CSCF2 directly attempts carrying out integrity verification and deciphering;

If this terminal is not set up SA before switching, then P-CSCF2 directly initiates 401 challenges, Invite is initiated handoff request message initiate the legitimacy authentication, shown in the dotted line of step 5 among Fig. 5.Here the standard authentication process of the relative IMS of authentication that Invite handoff request message is initiated has been omitted to the process that HSS reaches authorization data, has shortened the signaling plane time delay, and the IMS standard authentication process speed of prior art is wanted soon relatively.

If integrity verification and successful decryption, or message authentication success then continue next step flow process, otherwise return the handoff failure response to terminal 1.Hypothesis deciphering or message authentication success continue subsequent step in this example.

Step 6, P-CSCF2 sends Diameter-AAR message to SPDF2, with SDP application QoS reserved resource and the security control after switching, in message carried terminal 1 in switching the purpose packet domain the address and switch after SDP information, contain IP address, port and media description information in this SDP information.SPDF2 further carries out safe gate, qos policy and NAT and passes through by H.248 controlling SBC2, and this step will be finished terminal 1 and be connected with Media Stream between the switching target network SBC2.

So far, terminal 1 is to set up Media Stream between packet domain 2 and the SBC2 to connect by switching the purpose packet domain.

Step 7, P-CSCF2 send INFO to P-CSCF1 to initiate formal handoff request, carry the SDP after handoff request, the switching, user's information such as IMPU in this message.And send event charging information to CCF, carry and switch sign.

Step 8, P-CSCF1 receives that INFO is after the formal handoff request, sends event charging information to CCF, carries and switches sign.Simultaneously, P-CSCF1 initiates safe gate, qos policy control and NAT by Diameter message to SPDF1 and passes through order; SPDF1 determines safe gate, qos policy in conjunction with the local policy and the P-CSCF1 control information of receiving, carries out reserved resource by message control SBC2 H.248 according to corresponding strategy.

SPDF1 control SBC1 carries out following strategy execution, according to the SDP reserve media resource after switching, keep terminal 2 addresses send to terminal 1 switch before the Media Stream of SBC1 constant, before setting up terminal 1 simultaneously and switching SBC1 with switch after RTP Media Stream between the SBC2 address be connected.

If it is inconsistent before bandwidth, coding and the switching of the media information after switching, then P-CSCF1 will carry voice encoding and decoding and rate adapted Control Parameter in the Diameter of step 8 message, and carry out necessary Media layer bandwidth adaptation and code conversion by SPDF1 H.248 to control SBC1.

Step 9, P-CSCF1 sends 200 OK message to P-CSCF2, the success of indication handoff procedure.Send charge information to CCF, carry and switch sign.

Step 10, P-CSCF2 by SPDF2 control switch in the purpose packet domain access network SBC2 more the far-end address of new session be the IP address information of SBC1 in the handover source packet domain access network, be connected with RTP Media Stream between the SBC2 thereby set up SBC1.

So far, setting up Media Stream between the SBC2 in SBC1 in the handover source packet domain access network and the switching purpose packet domain access network connects.

Step 11, P-CSCF2 sends SIP INFO indication switching overall process to P-CSCF1 and finishes.

Step 12, P-CSCF2 sends 200 OK message to user terminal 1, finally indicates handover success.

Step 13, P-CSCF1 sends BYE message to terminal 1, removes the session between terminal 1 and the P-CSCF1.Set up the B2BUA incidence relation between the session and opposite end session between P-CSCF2 and the P-CSCF1 simultaneously; Behind handover success, P-CSCF2 will and P-CSCF1 between transmit interaction message between all terminals and the network in the switching session of having set up (as Update, Reinvite, Info etc.), all will be forwarded to the other end such as the terminal 2 of conversational communication, up to the user side conversation end in the B2BUA mode; Session between P-CSCF2 and the P-CSCF1 finishes by BYE.

So far, for signaling plane, terminal 1 is mutual by P-CSCF2-＞P-CSCF1 and network side; For the medium face, terminal 1 is that terminal 2 is carried out alternately by SBC2-＞SBC1 and opposite end.As seen, interactive signaling stream does not need S-CSCF and the SIP AS through the IMS core net between terminal 1 and the network, has promoted the switching efficiency of multimedia real-time session.Have again, in handoff procedure, reinstated under the situation of ipsec security alliance at User Network Interface (UNI), terminal 1 roams into to switch from handover source packet domain access network can directly reuse existing ipsec security alliance behind the purpose packet domain access network, do not need to rebulid Security Association, switch speed can obtain further lifting.

Specific implementation two: the terminal that the cross-grouping domain switching takes place inserts from same P-CSCF.

Figure 7 shows that the cross-grouping domain hand off signaling flow chart that inserts from same P-CSCF according to the terminal of the embodiment of the invention one.Terminal 1 and terminal 2 are being conversed, and terminal 1 switches to packet domain access network 2 from packet domain access network 1 and inserts the IMS network.

Step 1, terminal 1 detects network signal intensity, and decision is attached to the cut-in convergent node Node2 that switches the purpose packet domain again from the current cut-in convergent node Node1 of handover source packet domain.Terminal 1 is finished the authentication process of Access Network in the network of packet domain access network 2, by the address of DHCP acquisition IP address and P-CSCF, this P-CSCF address is identical with former P-CSCF address.

Step 2, terminal 1 sends Invite and initiates handoff request message to P-CSCF, and to initiate handoff request to P-CSCF, RequestURI fills in the address of P-CSCF, carries SDP and user ID after handoff request is indicated, switched in the message.This user ID can be IMPI or IMPU.

If set up IPSec SA between current terminal 1 and the P-CSCF, then terminal 1 still directly uses this IPSec SA that Invite message and subsequent message are carried out integrality and privacy protection; If do not set up IPSec SA as yet between current terminal 1 and the P-CSCF, then Invite message will send to P-CSCF with clear-text way.

Step 3, P-CSCF obtains user's safe context data according to user IMPU.

If set up IPSec SA between handoff request message indicating terminal 1 and the P-CSCF, then P-CSCF carries out integrity checking and deciphering to this handoff request message based on the IPSec SA with this user binding, as successful decryption, step below then continuing, otherwise directly return the handoff failure response to terminal 1;

If do not set up IPSec SA as yet between handoff request message indicating terminal 1 and the P-CSCF, then P-CSCF initiates 401 challenges based on user authentication information to terminal, and the response (SRES) of user terminal is verified, shown in the dotted line of step 3 among Fig. 7.As checking step below then continuing, otherwise directly return the handoff failure response to terminal 1.Here the standard authentication process of the relative IMS of authentication that Invite message is initiated has been omitted to the process that HSS reaches authorization data, has shortened the signaling plane time delay, and the IMS standard authentication speed of prior art is wanted soon relatively.

Hypothesis deciphering or message authentication success continue subsequent step in this example.

Step 4, P-CSCF sends Diameter-AAR message to SPDF2, with SDP application QoS reserved resource and the security control after switching, in message carried terminal 1 in switching purpose packet access network type the address and switch after SDP information.SPDF2 further carries out safe gate, qos policy and NAT and passes through by H.248 controlling SBC2, and this step will finish that the Media Stream between the SBC2 is connected in terminal 1 and the switching target packet domain.

So far, terminal 1 is to set up Media Stream between switching target packet domain access network 2 and the SBC2 to connect by the switching target packet domain.

Step 5, P-CSCF sends Diameter-AAR message to SPDF1, and SPDF1 determines safe gate, qos policy in conjunction with the local policy and the P-CSCF control information of receiving, carries out reserved resource by message control SBC1 H.248 according to corresponding strategy.

SPDF1 control SBC1 carries out following strategy execution, according to the SDP reserve media resource after switching, keep terminal 2 addresses send to terminal 1 switch before the Media Stream of SBC constant, before setting up terminal 1 simultaneously and switching SBC1 with switch after RTP Media Stream between the SBC2 address be connected.

If it is inconsistent before bandwidth, coding and the switching of the media information after switching, then P-CSCF will carry voice encoding and decoding and rate adapted Control Parameter in the Diameter message in step 5, and carry out necessary Media layer bandwidth adaptation and code conversion by SPDF1 H.248 to control SBC1.

Step 6, P-CSCF sends 200 OK message to terminal 1, finally indicates handover success.

So far, setting up Media Stream between SBC1 and the SBC2 connects.

Step 7, P-CSCF sends BYE message to terminal 1, and the switching purpose packet domain of terminal 1 and newly-built session between P-CSCF and the B2BUA incidence relation between the session of communication opposite end are set up in session between the handover source packet domain of dismounting terminal 1 and the P-CSCF simultaneously; Behind handover success, P-CSCF and terminal 1 all interaction messages in the session of switching destination are (as Update, Reinvite, Info etc.) all P-CSCF is forwarded to the other end such as the terminal 2 of communication session by the B2BUA mode, up to the user side conversation end.

So far, for signaling plane, terminal 1 is mutual by P-CSCF and network side; For the medium face, terminal 1 is that terminal 2 is carried out alternately by SBC2-＞SBC1 and opposite end.

For embodiment one, the SBC of handover source packet domain access network can be used as the natural anchor point (Achoring Point) that terminal 1 is connected with network side media bearer or session opposite end Media Stream, since handover source packet domain and the SBC that switches the purpose packet domain P-CSCF with set up Media Stream under SPDF controls and be connected, thereby user's face Media Stream handoff procedure of cross-grouping domain Access Network is transparent fully to callee side, need not to upgrade SDP, and worry that this Reinvite is blocked by the B2BUA AS that triggers in the caller and called users SIP session by Reinvite notice opposite end; Therefore, present embodiment possesses the value-added service integration capability more excellent than the VCC/MSC scheme of 3GPP standard recommendation.

In addition, embodiment one can realize switching in the switching of similar circuit territory source and be connected with the bifurcated switch that switches the destination Media Stream, thereby make that shorter handover delay becomes possibility by the SBC of handover source packet domain access network.

Embodiment two: the packet domain access network that switches source is not disposed SBC, "Policy and Charging Rules Function (PCRF) model of 3GPP definition is adopted in Access Network carrying control, be that P-CSCF divides into groups the cut-in convergent node layer (as GGSN by PCRF control, ASN-GW, BRAS etc.) finish and contain QOS management and security control in interior bearing bed resource control, all Media Streams of user conversation all pass through this grouping cut-in convergent node layer (as GGSN, ASN-GW, BRAS etc.).

Figure 8 shows that according to the terminal of the embodiment of the invention two and switch schematic diagram from the cross-grouping domain that different P-CSCF insert.Terminal 1 is that the handover source packet domain roams into packet domain access network 2 and promptly switches the purpose packet domain from packet domain access network 1 in this example, and former Media Stream is represented in the single-point setting-out among the figure, and two-dot chain line represents to switch the newly-built Media Stream in back, and black solid line is represented session signaling.The implementation procedure that cross-grouping domain switches is as follows:

2) terminal 1 directly sends and initiates handoff request message to P-CSCF2, starts handoff procedure with request, and the RequestURI of this message fills in the address of P-CSCF1, mainly carries cell in the message and comprises: the SDP after handoff request is indicated, switched, user ID etc.Wherein, describe source IP address, the port of user media stream among the SDP, target ip address, port reach information such as medium type.

If set up IPSec SA between terminal 1 and the P-CSCF1 based on IMS AKA agreement or other authentication patterns, then user ID, the handoff request indication of terminal 1 in the initiation handoff request message that P-CSCF2 sends do not done encryption as expressly sending, and other parts then are included in the encrypted tunnel.This SA tunnel is two-way, and the message of tunnel encapsulation is the message that is subjected between the terminal 1 to P-CSCF1 of ipsec protection.

3) after P-CSCF2 receives the handoff request message of self terminal 1, by the expressly user ID and the switching indication of part, learn that switching has taken place terminal 1, subsequently P-CSCF2 further send handoff request message to P-CSCF1 to ask for the safe context data between P-CSCF1 and the terminal 1.

4) P-CSCF1 obtains user's safe context data according to the IMPU of terminal, sends to P-CSCF2, and these safe context data can comprise the parameter of setting up SA between P-CSCF1 and the terminal 1, and/or authentication parameter.

If set up IPSec SA between terminal 1 and P-CSCF1, then P-CSCF1 sends to P-CSCF2 with the parameter of setting up SA between P-CSCF1 and the terminal 1 by the session of having set up, and P-CSCF1 sends charge information to CCF.

If P-CSCF2 does not obtain the parameter of IPSec SA then based on authentication parameter handoff request message is carried out authentication, the standard authentication process of the relative IMS of authentication has here been omitted the process that HSS reaches authorization data, shortened the signaling plane time delay, the IMS standard authentication speed of prior art wants fast relatively.

6) the P-CSCF2 initiation handoff request information later according to decoding sends a message to PCRF2, and the application reserved resource switches destination grouping cut-in convergent node such as GGSN, ASN-GW, BRAS etc. by PCRF2 control again, finishes resource reservation and policy control.

7) P-CSCF2 initiates formal handoff request to P-CSCF1.

8) after P-CSCF1 receives formal handoff request, the negotiation of the SDP information of the SDP of terminal 1 and terminal 2 after switching, the SDP information after P-CSCF2 returns negotiation.And can further send event charging information to CCF.

9) the SDP descriptor after P-CSCF2 further will consult is by setting up the conversation informing terminal 1 of SIP, this is engraved in terminal 1 and switches on the purpose packet domain access network that to set up with the session opposite end with the IP address of new application be that the unidirectional RTP Media Stream of terminal 2 is connected, and newly-built Media Stream connection is communicated with video and audio coding.

10) P-CSCF1 initiates ReInvite message to terminal 2, terminal 2 is after receiving ReInvite message, negotiation between the SDP that receives and the SDP of local terminal, can further the SDP after consulting be sent to P-CSCF1, and terminal 2 connects according to connecing the medium that SDP after the negotiation adjusts local terminal, finish terminal 1 and be connected foundation in switching purpose packet domain access network IP address with the two-way media stream of terminal 2, terminal 2 connects newly-built Media Stream and is communicated with video and audio coding.

So far, directly setting up two-way media stream between terminal 1 and the terminal 2 is connected.

11) subsequently P-CSCF1 to 1 tear down message of terminal with remove with terminal 1 between former session connection, finish to P-CSCF2 indication switching by removing response message simultaneously.

12) P-CSCF1 sends a message to PCRF1 subsequently, discharges resource with application.

13) P-CSCF1 is successful by discharging resource response message notice P-CSCF2 switching, and P-CSCF2 transmits the release resource response message that receives and gives terminal 1, and the indication handoff procedure is finished.And P-CSCF1 can further send charge information to CCF, carries and switches sign.

Behind handover success, P-CSCF2 will and P-CSCF1 between transmit interaction message such as Update between all terminals and the network, Reinvite, Info etc. on the switching session of having set up, up to the end side conversation end, end session again between P-CSCF2 and the P-CSCF1.Also promptly, for signaling plane, terminal 1 is mutual by P-CSCF2-＞P-CSCF1 and network side; For the medium face, terminal 1 directly and terminal 2 carry out alternately.

Figure 9 shows that based on signaling process figure embodiment illustrated in fig. 8.Terminal 1 and terminal 2 are being conversed, and terminal 1 desire is that packet domain access network 1 switches to that to switch the purpose packet domain be packet domain access network 2 from the handover source packet domain, inserts the IMS network by switching the purpose packet domain.

Step 1, terminal 1 detects network signal intensity, and decision is attached to the cut-in convergent node Node2 that switches the purpose packet domain again from the current cut-in convergent node Node1 of handover source packet domain.Terminal 1 is finished the authentication process of Access Network in the network of packet domain access network 2, obtain the address of IP address and P-CSCF2 by DHCP.

Step 2, terminal 1 sends Invite message to P-CSCF2, and to initiate handoff request to P-CSCF2, the RequestURI of this message fills in the address of P-CSCF1, carry handoff request in the message, information such as the SDP after switching and user ID, this user ID can be IMPI or IMPU.

If do not set up IPSec SA between terminal 1 and P-CSCF1 originally, then terminal 1 directly sends with clear-text way to the Invite initiation handoff request message that P-CSCF2 sends, and need P-CSCF2 that the legitimacy of user's handoff request is authenticated this moment.

Step 4, P-CSCF1 indicates the safe context data that obtain this terminal from this locality according to IMPU and the safe context request of user in the Invite message, sends to P-CSCF2 by 183 message.

Step 5, if this terminal has been set up SA before switching, then P-CSCF2 directly attempts Invite message is carried out integrity verification and deciphering;

If this terminal is not set up SA before switching, then P-CSCF2 directly initiates 401 challenges, Invite message is initiated the legitimacy authentication, shown in the dotted line of step 5 among Fig. 9.Here the standard authentication process of the relative IMS of authentication that Invite message is initiated has been omitted to the process that HSS reaches authorization data, has shortened the signaling plane time delay, and the IMS standard authentication speed of prior art is wanted soon relatively.

Step 6, P-CSCF2 sends INFO to begin to switch to initiate formal handoff request indication to P-CSCF1.Carry handoff request in this INFO, the SDP after switching, user's information such as IMPU.After P-CSCF1 received INFO handoff request message, the negotiation of the SDP of the SDP of terminal 1 and terminal 2 sent 200 OK message to P-CSCF2 after switching, and carried the SDP information after consulting.P-CSCF1 can also further send event charging information to CCF, carries to switch sign.

Step 7, P-CSCF2 sends Diameter-AAR message to PCRF2, carried terminal is in the SDP2 information of switching target side network in this message, PCRF2 further by Diameter control switching target side grouping cut-in convergent node such as GGSN, ASN-GW, BRAS etc., carries out safe gate, qos policy.

There is not strict sequencing between the above-mentioned

steps

6,7.

Step 8, SDP information after P-CSCF2 further will consult is by setting up 183 message informing terminals 1 of SIP session, this is engraved in terminal 1 to switch on the purpose packet domain access network to set up with the IP address of new application and is connected with the unidirectional RTP Media Stream of terminal 2, and newly-built Media Stream connection is communicated with video and audio coding.

So far, terminal 1 has been set up one-way media by to switch the purpose packet domain be packet domain 2 with terminal 2 and is flowed and be connected.

Step 9, P-CSCF1 initiates ReInvite message by S-CSCF1 to terminal 2 subsequently, carry the SDP information of switching purpose packet domain access network IP address in this message, terminal 2 is after receiving ReInvite message, negotiation between the SDP that receives and the SDP of local terminal, send 200 OK to P-CSCF1, can further carry the SDP information after the negotiation in this 200 OK message, and terminal 2 connects according to connecing the medium that SDP after the negotiation adjusts local terminal, finish terminal 1 and be connected foundation in switching purpose packet domain access network IP address with the two-way media stream of terminal 2, terminal 2 connects newly-built Media Stream and is communicated with video and audio coding.

So far, terminal 1 has been set up new two-way media by to switch the purpose packet domain be packet domain 2 with terminal 2 and is flowed and be connected.

Above-mentioned steps 9 needs only after step 6, and does not have strict sequencing between the

step

7,8.

Step 10, P-CSCF1 sends BYE message to terminal 1, removes the session between terminal 1 and the P-CSCF1.Set up the B2BUA incidence relation between the session and opposite end session between P-CSCF2 and the P-CSCF1 simultaneously.

Step 11, P-CSCF1 initiates Diameter AAR/AAA order to PCRF1 subsequently; The cut-in convergent node that PCRF1 switches purpose packet domain side by Diameter AAR/AAA control discharges the reserved resource that original carrying connects.

Step 12, P-CSCF1 sends 200 OK message to P-CSCF2, and the indication handoff procedure is finished.And can further send charge information, carry and switch sign to CCF.

Step 13, P-CSCF2 sends 200 OK message to user terminal 1, finally indicates handover success.Behind handover success, P-CSCF2 will and P-CSCF1 between transmit interaction message between all terminals and the network in the switching session of having set up (as Update, Reinvite, Info etc.) all will be forwarded to the other end such as the terminal 2 of conversational communication in the B2BUA mode, up to the user side conversation end; Session between P-CSCF2 and the P-CSCF1 finishes by Bye.

So far, for signaling plane, terminal 1 is mutual by P-CSCF2-＞P-CSCF1 and network side; For the medium face, terminal 1 directly and terminal 2 carry out alternately.As seen, interactive signaling stream does not need S-CSCF and the SIP AS through the IMS core net between terminal 1 and the network, has promoted the switching efficiency of multimedia real-time session.Have again, in handoff procedure, reinstated under the situation of ipsec security alliance at User Network Interface (UNI), terminal 1 roams into to switch from handover source packet domain access network can directly reuse existing ipsec security alliance behind the purpose packet domain access network, do not need to rebulid Security Association, switch speed can obtain further lifting.

Figure 10 shows that the cross-grouping domain hand off signaling flow chart that inserts from same P-CSCF according to the terminal of the embodiment of the invention two.Terminal 1 and terminal 2 are being conversed, and terminal 1 switches to packet domain access network 2 from packet domain access network 1 and inserts the IMS network.

Step 1, terminal 1 detects network signal intensity, and decision is attached to the cut-in convergent node Node2 that switches the purpose packet domain again from the current cut-in convergent node Node1 of handover source packet domain.Terminal 1 is finished the authentication process of Access Network in the network of packet domain access network 2, obtain the address of new IP address and P-CSCF by DHCP, and this P-CSCF address is identical with former P-CSCF address.

Step 3, P-CSCF obtains user's safe context data according to user IMPU.

If set up IPSec SA between handoff request message indicating terminal 1 and the P-CSCF, then P-CSCF carries out integrity checking and deciphering to this Invite message based on the IPSec SA with this user binding, as successful decryption, step below then continuing, otherwise directly return the handoff failure response to terminal 1;

If do not set up IPSec SA as yet between handoff request message indicating terminal 1 and the P-CSCF, then P-CSCF initiates 401 challenges based on user authentication information to terminal, and the response of user terminal is verified, shown in the dotted line of step 3 among Figure 10.As checking step below then continuing, otherwise directly return the handoff failure response to terminal 1.Here the standard authentication process of the relative IMS of authentication that Invite handoff request message is initiated has been omitted to the process that HSS reaches authorization data, has shortened the signaling plane time delay, and the IMS standard authentication speed of prior art is wanted soon relatively.

Step 4, P-CSCF sends Diameter-AAR message to PCRF2, SDP information after carried terminal 1 switches in this message, PCRF2 further by cut-in convergent node such as GGSN, ASN-GW, the BRAS etc. of Diameter control switching target packet domain side, carries out safe gate, qos policy.

Step 5, P-CSCF initiates ReInvite message to terminal 2 subsequently, terminal 2 is after receiving ReInvite message, negotiation between the SDP that receives and the SDP of local terminal, send 200 OK to P-CSCF, can further carry the SDP information after the negotiation in this 200 OK message, and terminal 2 connects according to connecing the medium that SDP after the negotiation adjusts local terminal.

Step 6, SDP information after P-CSCF further will consult is by setting up 183 message informing terminals 1 of SIP session, finish terminal 1 and be connected foundation in switching destination network ip address with the two-way media stream of terminal 2, terminal 1 connects newly-built Media Stream and is communicated with video and audio coding.

So far, terminal 1 has been set up new two-way media by to switch the purpose packet domain be packet domain access network 2 with terminal 2 and is flowed and be connected.

Step 7, P-CSCF sends BYE message to terminal 1, removes the session between terminal 1 and the P-CSCF.

Step 8, P-CSCF initiates Diameter AAR/AAA order to PCRF1 subsequently; The cut-in convergent node that PCRF1 switches purpose packet domain side by Diameter AAR/AAA control discharges the reserved resource that original carrying connects.

Step 9, P-CSCF sends 200 OK message to terminal 1, finally indicates handover success.

So far, for signaling plane, terminal 1 is mutual by P-CSCF and network side; For the medium face, terminal 1 directly and terminal 2 carry out alternately.Behind handover success, P-CSCF will set up the B2BUA mapping relations of switching destination session and terminal 2 sessions, and the interactive information of all terminals of transparent transmission and network side, up to the end side conversation end.

For embodiment two, because the Media Stream of network side media bearer or session opposite end directly links to each other with switching destination media address after switching, therefore there is not alternate route in its Media Stream, and it is little to compare mobile IP mode medium time delay, helps realizing that seamlessly Multimedia session switches experience.

Use the changing method of cross-grouping domain of the present invention, make that multimode terminal need not to carry out complete IMS network registry flow process once more after switching to switching purpose packet domain, the speed that switch in the territory is cut in the grouping of striding that has effectively promoted the multimedia real-time session.And in handoff procedure, interactive signaling stream does not need S-CSCF and the SIP AS through the IMS core net between terminal and the network, has promoted the switching efficiency of multimedia real-time session.Have again, in handoff procedure, reinstated under the situation of ipsec security alliance at User Network Interface (UNI), terminal can directly be reused existing ipsec security alliance after switching the purpose Access Network being roamed into from the handover source Access Network, and not needing to rebulid Security Association, switch speed can obtain further lifting.

Need explanation in addition a bit, more than called among all embodiment all be that example describes with the terminal, in actual applications, called certain server in also might network etc., for the present invention, specifically be the not strict restriction of which kind of equipment to callee side.

The present invention also provides a kind of cross-grouping domain switched system based on IP Multimedia System, comprise and set up first terminal that Media Stream connects, the P-CSCF of the handover source packet domain of described first terminal is connected controlled entity with the P-CSCF and the medium that switch the purpose packet domain

Described medium connect controlled entity and comprise: first terminal is switched the SPDF and the SBC of purpose packet domain, and the SPDF of handover source packet domain and SBC;

Described first terminal is switched the SPDF of purpose packet domain, is used to receive from the P-CSCF in the described switching purpose packet domain comprise the message that first terminal is switched back SDP information, and the SBC that the purpose packet domain is switched in control carries out resource reservation;

The SPDF of the described first terminal handover source packet domain is used to receive the control command from the P-CSCF in the described handover source packet domain, and the SBC of control handover source packet domain carries out resource reservation;

The SBC of described switching purpose packet domain, after being used to carry out resource reservation, the Media Stream of setting up between the SBC of described first terminal and described switching purpose packet domain is connected;

The SBC of described handover source packet domain after being used to carry out resource reservation, keeps called constant with the Media Stream first terminal handover source packet domain SBC, and the SBC that sets up described handover source packet domain simultaneously is connected with the Media Stream that switches purpose packet domain SBC.

Described medium connect controlled entity and comprise: switch the PCRF and the grouping cut-in convergent node of purpose packet domain, and the PCRF of handover source packet domain and grouping cut-in convergent node;

The PCRF of described switching purpose packet domain, the P-CSCF that is used to receive from described switching purpose packet domain comprises by the SDP behind first terminal switching back SDP and the called SDP negotiation, and the control of purpose grouping cut-in convergent node execution respective resources is switched in control;

The PCRF of described handover source packet domain is used to receive the order from the indexed resource release of described handover source packet domain P-CSCF, and the grouping cut-in convergent node in the control handover source packet domain discharges the reserved resource that original carrying connects.

The present invention also provides a kind of cross-grouping domain switched system based on IP Multimedia System, comprise and set up first terminal that Media Stream connects, be the handover source packet domain of described first terminal and the P-CSCF of switching purpose packet domain service simultaneously, and medium connect controlled entity

Described first terminal is switched the SPDF of purpose packet domain, is used to receive from described P-CSCF comprise the message that first terminal is switched back SDP information, and the SBC that the purpose packet domain is switched in control carries out resource reservation;

The SPDF of the described first terminal handover source packet domain is used to receive the control command from described P-CSCF, and the SBC of control handover source packet domain carries out resource reservation;

The SBC of described handover source packet domain after being used to carry out resource reservation, keeps called constant with the Media Stream first terminal handover source packet domain SBC, and the SBC that sets up described handover source packet domain simultaneously is connected with the Media Stream of the SBC that switches the purpose packet domain.

The PCRF of described switching purpose packet domain is used to receive the message that comprises described first terminal switching back SDP from described P-CSCF, and control switching purpose packet domain cut-in convergent node is carried out respective resources and controlled;

The PCRF of described handover source packet domain is used to receive the order from the indexed resource release of described P-CSCF, and the grouping cut-in convergent node of control handover source packet domain discharges the reserved resource that original carrying connects.

The present invention also provides a kind of P-CSCF, serves the first terminal handover source packet domain, comprising:

Described medium connect controlled entity and comprise SBC or PCRF.

The present invention also provides a kind of P-CSCF, serves first terminal and switches the purpose packet domain, comprising:

Described P-CSCF also comprises: parameter acquiring unit is used for obtaining certificate parameter from the P-CSCF of the first terminal handover source packet domain; Authentication unit is used for according to described certificate parameter the initiation handoff request message that receives being verified, checking by after reinform described handover trigger unit and send to the P-CSCF that switches the source packet domain.

The above is preferred embodiment of the present invention only, is not to be used to limit protection scope of the present invention.All any modifications of being done within the spirit and principles in the present invention, be equal to replacement, improvement etc., all be included in protection scope of the present invention.

Claims

1. cross-grouping domain switching method based on IP Multimedia System, first terminal are successfully set up Media Stream and are connected; The Proxy Call Session Control Function P-CSCF that moves to the handover source packet domain of switching purpose packet domain and described first terminal when first terminal from the handover source packet domain and the P-CSCF that switches the purpose packet domain is characterized in that this method also comprises not simultaneously:

2. method according to claim 1 is characterized in that, the P-CSCF in the described switching purpose packet domain also comprises before sending handoff request:

The P-CSCF of described switching purpose packet domain receives the message from the initiation handoff request of described first terminal, message to described initiation handoff request from first terminal is verified, after checking was passed through, the P-CSCF to described handover source packet domain sent handoff request again.

3. method according to claim 2 is characterized in that, if the P-CSCF of described first terminal and handover source packet domain has set up Security Association, then Yan Zheng step comprises:

The P-CSCF of described switching purpose packet domain obtains the Security Association parameter from the P-CSCF of described handover source packet domain, use described Security Association parameter described initiation handoff request is carried out integrity verification and deciphering, if integrity verification and successful decryption, then checking is passed through; Otherwise checking is not passed through;

If the verification passes, described handoff request is the P-CSCF that sends to described handover source packet domain by tunnel style.

4. method according to claim 3 is characterized in that, if the P-CSCF of described first terminal and handover source packet domain does not set up Security Association, then the step of described checking comprises:

The P-CSCF of described switching purpose packet domain obtains authentication parameter from the P-CSCF of described handover source packet domain, uses described authentication parameter described initiation handoff request is carried out authentication, if the authentication success, then checking is passed through; Otherwise checking is not passed through;

If the verification passes, described handoff request is the P-CSCF that sends to described handover source packet domain by mode expressly.

5. method according to claim 1, it is characterized in that, the P-CSCF of P-CSCF in the described switching purpose packet domain in described handover source packet domain sends before the handoff request, also comprises: the Session Border Controller SBC that switches the P-CSCF control switching destination packet domain of purpose packet domain carries out resource reservation.

6. method according to claim 5 is characterized in that, after the P-CSCF in the described handover source packet domain receives handoff request, also comprises: the SBC of the P-CSCF control handover source packet domain of handover source packet domain carries out resource reservation.

7. method according to claim 6 is characterized in that, described first terminal comprises by the step of switching the new media bearer of back packet domain and called foundation:

After the SBC that switches the purpose packet domain carries out resource reservation, set up described first terminal and be connected with Media Stream between the described switching purpose packet domain SBC;

After handover source packet domain SBC carries out resource reservation, keep called Media Stream constant with the interior SBC of the first terminal handover source packet domain, set up described handover source packet domain SBC simultaneously and be connected with the Media Stream that switches purpose packet domain SBC;

Described first terminal by described switching purpose packet domain SBC, handover source packet domain SBC and called between set up new media bearer.

8. method according to claim 1 is characterized in that, after the P-CSCF of described handover source packet domain receives handoff request, also comprises:

SDP information after the P-CSCF of described handover source packet domain switches described first terminal and called SDP information are held consultation; Send the P-CSCF that switches the purpose packet domain to consulting back SDP information;

The P-CSCF in described switching destination group territory switches destination grouping cut-in convergent node by the "Policy and Charging Rules Function PCRF control of switching the purpose packet domain and carries out respective resources control according to consulting back SDP information.

9. method according to claim 8 is characterized in that, described first terminal comprises by the step of switching the new media bearer of back packet domain and called foundation:

Described first terminal receives comprising of adaptive switched purpose packet domain P-CSCF of described message of consulting back SDP information, according to described negotiations back SDP information, by switch the back packet domain set up with called between one-way media flow and be connected;

Described called reception is held consultation the SDP information of receiving from the SDP information that first terminal is switched purpose grouping domain IP address that comprises of handover source packet domain P-CSCF with the SDP information of local terminal, adjust the medium connection of local terminal according to the SDP after consulting;

Described first terminal is directly set up new media bearer with called by switching the back packet domain.

10. method according to claim 9 is characterized in that, also comprises:

The PCRF of P-CSCF in the handover source packet domain sends the order that indexed resource discharges in the handover source packet domain, and the PCRF in the described handover source packet domain discharges the reserved resource that original carrying connects according to the grouping cut-in convergent node that receives order control handover source packet domain.

11. according to Claim 8 or 10 described methods, it is characterized in that described grouping cut-in convergent node comprises Gateway GPRS Support Node GGSN, IAD ASN-GW or BAS Broadband Access Server BRAS at least.

12., it is characterized in that the step of the P-CSCF of the P-CSCF of described realization first terminal by switching the purpose packet domain, handover source packet domain and the Signalling exchange of network side comprises according to claim 7 or 10 described methods:

The P-CSCF of described handover source packet domain sends out message to remove the former session connection between self and described first terminal to described first terminal; Set up the back-to-back user agent incidence relation between self and the described switching purpose packet domain P-CSCF simultaneously, make described first terminal realize Signalling exchange by described switching purpose packet domain P-CSCF, handover source packet domain P-CSCF and network side successively.

13. successfully setting up Media Stream, the cross-grouping domain switching method based on IP Multimedia System, first terminal connect; When the P-CSCF that moves to the handover source packet domain of switching purpose packet domain and described first terminal from the handover source packet domain when first terminal is same P-CSCF with the P-CSCF that switches the purpose packet domain, it is characterized in that this method also comprises:

14. method according to claim 13 is characterized in that, the initiation handoff request that described P-CSCF receives is from described first terminal;

Described P-CSCF receives after the message of initiating handoff request, further comprises:

Message to described initiation handoff request from first terminal is verified, after checking is passed through, carries out subsequent step again.

15. method according to claim 14 is characterized in that, if described first terminal has been set up Security Association with the P-CSCF that switches in the source packet domain, then the step of described checking comprises:

Described P-CSCF uses described Security Association parameter described initiation handoff request is carried out integrity verification and deciphering from obtaining the Security Association parameter, if integrity verification and successful decryption, then checking is passed through; Otherwise checking is not passed through;

If the verification passes, described handoff request is to send to described P-CSCF by tunnel style.

16. method according to claim 14 is characterized in that, if described first terminal is not set up Security Association with the P-CSCF that switches in the source packet domain, then the step of described checking comprises:

Described P-CSCF obtains authentication parameter, uses described authentication parameter described initiation handoff request is carried out authentication, if the authentication success, then checking is passed through; Otherwise checking is not passed through;

If the verification passes, described handoff request is to send to described P-CSCF by clear-text way.

17. method according to claim 13 is characterized in that, described P-CSCF control switching purpose network side comprises for the step of the medium reservation resource after switching:

The SBC that described P-CSCF control is switched in the purpose packet domain carries out resource reservation.

18. method according to claim 17 is characterized in that, also comprises: described P-CSCF carries out resource reservation by the SBC in the handover source packet domain SPDF control handover source packet domain.

19. method according to claim 18 is characterized in that, described first terminal comprises by the step of switching the new media bearer of back packet domain and called foundation:

After the SBC that switches the purpose packet domain carried out resource reservation, the Media Stream of setting up between the SBC of described first terminal and described switching purpose packet domain was connected;

After the SBC of handover source packet domain carries out resource reservation, keep called constant with the Media Stream first terminal handover source packet domain SBC, the SBC that sets up described handover source packet domain simultaneously is connected with the Media Stream of the SBC that switches the purpose packet domain;

The SBC of the SBC of described first terminal by described switching purpose packet domain, handover source packet domain and calledly set up new media bearer.

20. method according to claim 13 is characterized in that, described control switching purpose network side comprises for the step of the medium reservation resource after switching:

Described P-CSCF sends the message of carrying first terminal switching back SDP information and arrives the PCRF that switches in the purpose packet domain, controls the control of switching target side grouping cut-in convergent node execution respective resources by the PCRF in the described switching destination packet domain.

21. method according to claim 20 is characterized in that, described first terminal comprises by the step of switching the new media bearer of back packet domain and called foundation:

Described first terminal receives the message of consulting back SDP information that comprises from described P-CSCF, according to described negotiations back SDP information, sets up to flow with called one-way media and is connected by switching the back packet domain;

Described called reception is held consultation the SDP information of receiving from the SDP information that first terminal is switched purpose grouping domain IP address that comprises of described P-CSCF with the SDP information of local terminal, adjust the medium connection of local terminal according to the SDP after consulting;

Described first terminal is directly set up new media bearer with called by switching the purpose packet domain.

22. method according to claim 21, it is characterized in that, also comprise: described P-CSCF sends the order that indexed resource discharges to the PCRF of handover source packet domain, and the PCRF of described handover source packet domain discharges the reserved resource that original carrying connects according to the grouping cut-in convergent node that receives order control handover source packet domain.

23. cross-grouping domain switched system based on IP Multimedia System, it is characterized in that, comprise and set up first terminal that Media Stream connects, the P-CSCF of the handover source packet domain of described first terminal is connected controlled entity with the P-CSCF and the medium that switch the purpose packet domain

24. system according to claim 23 is characterized in that, described medium connect controlled entity and comprise: first terminal is switched the SPDF and the SBC of purpose packet domain, and the SPDF of handover source packet domain and SBC;

25. system according to claim 24 is characterized in that, described medium connect controlled entity and comprise: switch the PCRF and the grouping cut-in convergent node of purpose packet domain, and the PCRF of handover source packet domain and grouping cut-in convergent node;

26. cross-grouping domain switched system based on IP Multimedia System, it is characterized in that, comprise and set up first terminal that Media Stream connects, is the handover source packet domain of described first terminal and the P-CSCF of switching purpose packet domain service simultaneously, and medium connect controlled entity

27. system according to claim 26 is characterized in that, described medium connect controlled entity and comprise: first terminal is switched the SPDF and the SBC of purpose packet domain, and the SPDF of handover source packet domain and SBC;

28. system according to claim 26 is characterized in that, described medium connect controlled entity and comprise: switch the PCRF and the grouping cut-in convergent node of purpose packet domain, and the PCRF of handover source packet domain and grouping cut-in convergent node;

29. a Proxy Call Session Control Function P-CSCF serves the first terminal handover source packet domain, it is characterized in that, comprising:

30. P-CSCF according to claim 29 is characterized in that, described medium connect controlled entity and comprise SBC or PCRF.

31. a Proxy Call Session Control Function P-CSCF serves first terminal and switches the purpose packet domain, it is characterized in that, comprising:

32. P-CSCF according to claim 31 is characterized in that, described P-CSCF also comprises:

Parameter acquiring unit is used for obtaining certificate parameter from the P-CSCF of the first terminal handover source packet domain;

Authentication unit is used for according to described certificate parameter the initiation handoff request message that receives being verified, checking by after reinform described handover trigger unit and send to the P-CSCF that switches the source packet domain.