WO2009065334A1

WO2009065334A1 - Switching method, system and device across packet domain based on the ip multimedia subsystem

Info

Publication number: WO2009065334A1
Application number: PCT/CN2008/072752
Authority: WO
Inventors: Jiongjiong Gu
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-11-02
Filing date: 2008-10-20
Publication date: 2009-05-28
Also published as: CN101175329A

Abstract

The invention includes a method, system and device for switching across packet domain based on IP multimedia subsystem, the invention's application make that multi mode terminal do not need to register to IMS network integrallty once more after it switched to the switching target packet domain, and that the across packet domain switching rate for multimedia real-time session be improved effectively. And, in the process of switching, the flows of interaction signals between terminal and network do not need relating to the S-CSCF and SIP AS of IMS core network, which improve the switching efficiency of the multimedia real-time session.

Description

Cross-packet domain switching method, system and device based on IP multimedia subsystem This application claims to be submitted to the Chinese Patent Office on November 2, 2007, the application number is 200710167256.1, and the invention name is "IP multimedia subsystem-based cross-packet domain switching method" The priority of the Chinese Patent Application, the entire disclosure of which is incorporated herein by reference. Technical field

The present invention relates to the field of communications technologies, and in particular, to an inter-packet domain switching method, system and device based on an IP Multimedia Subsystem (IMS).

Background technique

As the core network architecture of future fixed and mobile convergence evolution development goals, the IMS Core Network (IMS Core) needs to support simultaneous sharing by multiple access technologies, and must ensure that end users are provided with independent and fixed multiple access. Uniform continuity of the approach and multimedia service experience.

With General Packet Radio Service (GPRS), Universal Mobile Telecommunication System (UMTS), Code Division Multiple Access (CDMA), Wireless Fidelity (WiFi) The emergence and development of various types of wireless data access network technologies such as Worldwide Interoperability for Microwave Access (WiMAX), user-centric multimode terminals (eg GSM/WiFi, WiMax/WiFi, UMTS) /CDMA) will gradually gain popularity in everyday communication applications. Through the multi-mode terminal, users no longer need to apply for independent terminals for each type of access technology, and can adaptively access a variety of different access technologies during the roaming mobile process through a single user identity and the terminal, and enjoy seamless Continuous multimedia business experience. Therefore, how to ensure that the switching process of multimedia service sessions is transparent to users and realize the universal mobility of access technologies is a key issue that must be solved by IMS networks. It is also one of the most important characteristics of IMS networks that are different from traditional softswitch networks.

The existing solution for solving the problem of multimedia service continuity (MSC) mainly solves the problem of domain selection and cross-domain handover of IMS multimedia sessions between different packet access networks through the MSC Application Server (MSC AS) control based on the service application layer. . Specifically, when the terminal monitors that the cross-packet domain switching needs to be performed according to the network coverage, the terminal performs the authentication registration of the access in the new packet domain, obtains the IP address, and then registers with the IMS domain. After the registration of the IMS domain is successful, a SIP INVITE request is initiated, and the handover indication (such as the VDI obtained from the network side or other values of the configuration) is carried in the signaling. After receiving the INVITE request, the MSC AS analyzes the signaling to identify the handover indication, and performs a handover operation. The original call side initiates a RelNVITE message and re-negotiates the media with the newly established call. When a new call is established, the MSC AS then tears down the old call. Summary of the invention

The embodiments of the present invention provide a cross-packet domain switching method, system, and device based on an IP multimedia subsystem, which can implement seamless handover of IMS real-time multimedia services across packet domains, shorten handover signaling plane delay, and improve service experience. Continuity.

The technical solution of the embodiment of the present invention includes:

A cross-packet domain switching method based on an IP multimedia subsystem, the first terminal has successfully established a media stream connection; when the first terminal moves from the handover source packet domain to the handover destination packet domain and the handover source packet domain of the first terminal When the proxy call session control function P-CSCF is different from the P-CSCF of the handover destination packet domain, the method further includes:

The P-CSCF of the handover source packet domain receives a handover request from the handover destination packet domain P-CSCF, establishes a connection with the P-CSCF of the handover destination packet domain, and implements the P-CSCF of the first terminal by switching the destination packet domain. And switching the P-CSCF of the source packet domain to perform signaling interaction with the network side;

The first terminal establishes a new media bearer with the called party after the handover, and implements cross-packet domain switching.

A cross-packet domain switching method based on an IP multimedia subsystem, the first terminal has successfully established a media stream connection; when the first terminal moves from the handover source packet domain to the handover destination packet domain and the handover source packet domain of the first terminal When the P-CSCF is the same P-CSCF as the P-CSCF of the handover destination packet domain, the method further includes:

After receiving the handover request, the P-CSCF controls the handover destination network side to be the reserved media reserved resource, so that the first terminal performs signaling interaction with the network side through the P-CSCF;

A cross-packet domain switching system based on an IP multimedia subsystem, comprising a first terminal that has established a media stream connection, a P-CSCF of the handover source packet domain of the first terminal, and a P-CSCF and a medium of the handover destination packet domain Connection control entity,

The P-CSCF of the handover source packet domain is configured to receive a handover request, and the handover destination packet The P-CSCF of the domain establishes a connection, so that the first terminal performs the media resource control operation by the media connection control entity by switching the P-CSCF of the destination packet domain, and the P-CSCF of the handover source packet domain to perform signaling interaction with the network side;

The first terminal is configured to establish a new media bearer with the called party after the handover, to implement cross-packet domain switching.

A cross-packet domain switching system based on an IP multimedia subsystem, comprising a first terminal that has established a media stream connection, a switching source packet domain of the first terminal, and a P-CSCF serving the handover destination packet domain, and a medium Connection control entity,

The P-CSCF is configured to receive a handover request, and control the handover destination network side to reserve resources for the switched media, so that the first terminal performs signaling interaction with the network side by cutting the P-CSCF; The entity performs media resource control operations;

A proxy call session control function P-CSCF, which serves to switch the source packet domain to the first terminal, and includes:

The signaling control unit is configured to receive a handover request, establish a connection with the P-CSCF in the handover destination side packet domain, so that the first terminal implements the P-CSCF of the handover destination packet domain, the P-CSCF of the handover source packet domain, and the network side. Signaling interaction;

The media bearer control unit is configured to control the media connection control entity to perform a media resource control operation. A proxy call session control function, the P-CSCF, serves the first terminal to switch the destination packet domain, including:

Switching the triggering unit, receiving the initiated handover request from the first terminal, and transmitting the request to the P-CSCF of the handover source packet domain;

The media bearer control unit is configured to control the media connection control entity in the handover destination packet domain to perform resource reservation.

By applying the invention, the multi-mode terminal enables the multi-mode terminal to perform the complete IMS network registration process again after switching to the handover destination packet domain, thereby effectively improving the speed of the cross-packet domain switching of the multimedia real-time session. Moreover, in the handover process, the signaling flow exchanged between the terminal and the network does not need to pass through the S-CSCF and the SIPAS of the IMS core network, thereby improving the switching efficiency of the multimedia real-time session. DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any creative work.

FIG. 1 is a schematic diagram of cross-packet domain switching of a terminal accessing from different P-CSCFs according to Embodiment 1 of the present invention; FIG.

2 is a signaling flow chart based on the embodiment shown in FIG. 1;

FIG. 3 is a diagram showing a security association (SA) established by tunneling in an IMS handover process according to an embodiment of the present invention;

FIG. 4 is a flow chart showing cross-packet domain switching signaling of a terminal accessing from the same P-CSCF according to Embodiment 1 of the present invention; FIG.

FIG. 5 is a schematic diagram of cross-packet domain switching of terminals accessed by different P-CSCFs according to Embodiment 2 of the present invention; FIG.

Figure 6 is a flow chart showing the signaling based on the embodiment shown in Figure 5;

FIG. 7 is a flow chart showing cross-packet domain switching signaling of a terminal accessing from the same P-CSCF according to Embodiment 2 of the present invention.

detailed description

In carrying out the creation process of the present invention, the inventors found that the aforementioned prior art cannot achieve seamless switching, and thus the service experience is poor. The specific prior art described above has at least the following problems:

1) Since the 3GPP MSC is based on the continuation of the VCC scheme, each time the SIP application layer handover operation is performed, in addition to the UE completing the IP network layer attachment and authentication process, the UE needs to re-send the association, at the same time. The CSCF also needs to complete the IMS user subscription data download from the HSS, resulting in a large delay in the handover signaling plane and reducing the continuity of the service experience.

2) As shown in step 8-22, all the switching service flows in this solution need to traverse the P-CSCF and the S-CSCF, and the MSC AS interacts with the terminal to further increase the signaling plane switching delay. 3) Since the terminal detects the new target packet domain network signal and initiates SIP registration, the existing SIP session will not be released, thus determining that the dual mode terminal must use other IMPU to initiate the annotation.

4) The multimedia session switching process relies on the MSC AS intercepting the control of the SIP session and controlling the handover process. The MSC AS needs to implement the integration with other value-added services SIP AS by triggering the rule chain according to the priority serialized iFC. If other SIP ASs operating in the back-to-back user service mode (B2BUA) mode cannot transparently transmit RelNVITE messages from the MSC AS, the handover will fail; therefore, the successful integration of the handover scheme with other value-added services AS will be affected to some extent. Other AS messaging capabilities are constrained.

BRIEF DESCRIPTION OF THE DRAWINGS The technical solutions in the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative work are within the scope of the present invention.

First, the definition of the IMS tongue-to-packet domain handover according to the embodiment of the present invention is described: assuming that the multimedia session of the IMS terminal 1 is in progress, the IMS terminal 1 has accessed the IMS through the packet domain access network 1, and its service access The aggregation node is node 1 (Nodel ). When the IMS terminal 1 roams from the packet domain access network 1 to another packet domain access network 2, its service access aggregation node 2 (Node2) is different from the access aggregation node 1 And it is desirable to maintain the continuity of the currently ongoing IMS in this process, and the IMS terminal 1 is said to have "cross-packet" regardless of whether the packet domain access network 1 and the packet domain access network 2 have the same access type. The handover of the domain, in which the packet domain access network 1 is referred to as a "switching source packet domain", and the packet domain access network 2 is referred to as a "switching destination packet domain".

The above-mentioned packet domain access network 1 and packet domain access network 2 may be one of any type of mobile packet broadband access, such as WiFi/WiMAX, GPRS/UMTS/HSPA, CDMA/EVDO, and the like.

The embodiment of the present invention provides a cross-packet domain switching method based on an IP multimedia subsystem, including: a media stream connection is established between the first terminal and the second terminal, and the first terminal re-registers to the handover destination side packet. If the proxy call control function (P-CSCF) in the handover source side packet domain of the first terminal is different from the P-CSCF in the handover destination side packet domain, the P-CSCF in the handover source side packet domain is different. After receiving the handover request, establishing a connection with the P-CSCF in the handover destination side packet domain, and controlling the first terminal handover destination side to pass through the handover destination side packet domain. The P-CSCF, the P-CSCF in the switching source-side packet domain establishes a session with the second terminal, and performs signaling interaction; the P-CSCF in the switching source-side packet domain controls the first terminal to pass the switched packet domain Establishing a new media bearer with the second terminal to implement cross-packet domain switching.

The embodiment of the present invention further provides a cross-packet domain switching method based on an IP multimedia subsystem, where a media stream connection is established between the first terminal and the second terminal; the first terminal is re-registered into the handover destination side packet domain. And when the P-CSCF in the handover source side packet domain of the first terminal is the same P-CSCF as the P-CSCF in the handover destination side packet domain, the P-CSCF establishes the first after receiving the handover request. The terminal switches the session between the destination side and the second terminal, and transparently transmits the interaction information between the terminal and the network side to implement signaling interaction; the P-CSCF controls the first terminal to pass the switched packet domain and the second terminal. A new media bearer is established between them to implement cross-packet domain switching.

Embodiment 1: The packet domain access network on the switching source side is deployed with a Session Border Controller (SBC), and the access network bearer control adopts telecom and Internet convergence services and advanced networks (TISPAN, Telecommunications and Internet Converged Services and Protocols for Advanced) Networking) The service-based policy decision function (SPDF) model defined by the protocol, that is, the P-CSCF controls the SBC to perform bearer layer resource control including network address translation (NAT) traversal, quality of service (QOS) management, and security control through SPDF control SBC. All media streams of the user session pass through the SBC.

The specific implementation manner 1: The terminal that crosses the packet domain handover is accessed from different P-CSCFs.

FIG. 1 is a schematic diagram of cross-packet domain switching of terminals accessed by different P-CSCFs according to Embodiment 1 of the present invention. In this example, the terminal 1 roams from the packet domain access network 1, that is, the handover source packet domain to the packet domain access network 2, that is, the handover destination packet domain, where the single-dotted line indicates the original media stream, and the double-dotted line indicates the new media stream after the handover. The black solid line indicates session signaling. The implementation process of cross-packet domain switching is as follows:

1) The terminal 1 completes the authentication process of the access network in the access aggregation node (P-CSCF2) of the handover destination packet domain, and obtains the IP address in the handover destination packet domain and the address of the P-CSCF2 entry point.

2) The terminal 1 directly sends a handover request message to the P-CSCF2 to request to initiate the handover process. The RequestURI of the message fills in the address of the P-CSCF1, and the main carried cell in the message includes: a handover request indication, a session description protocol after the handover (SDP), user ID, etc. The SDP describes information such as the source IP address, port, destination IP address, port, and media type of the user media stream. IPSec SA (IPSec, Internet Protocol Security, IP Security Protocol; SA, Security) has been established between the terminal 1 and the P-CSCF1 based on the IMS-based Authentication and Key Agreement (AKA) protocol or other authentication mode. In the alliance, the user identifier and the handover request indication in the originating handover request message sent by the terminal 1 to the P-CSCF2 are sent as plaintext without encryption, and other parts are included in the encrypted channel. The SA tunnel is bidirectional. The packet encapsulated by the tunnel is a packet between the terminal 1 and the P-CSCF1 protected by IPSec.

If the IPSec SA is not established between the terminal 1 and the P-CSCF1, the originating handover request message sent by the terminal 1 to the P-CSCF2 is sent in plain text. In this case, the P-CSCF2 is required to authenticate the validity of the handover request.

The sending and receiving ports of the IP header encapsulated in the message exchange between the P-CSCF2 and the terminal 1 are independent of the SA between the original P-CSCF1 and the terminal 1.

3) After receiving the handover request message from the terminal 1, the P-CSCF2 learns that the handover has occurred in the terminal 1 through the user identifier and the handover indication in the plaintext portion, and then the P-CSCF2 further sends a handover request message to the P-CSCF1 to request Security context data between P-CSCF1 and terminal 1.

4) The P-CSCF1 obtains the security context data of the user according to the user IMPU and sends it to the P-CSCF2, and the security context data may include parameters for establishing SA between the P-CSCF1 and the terminal 1, and/or authentication parameters.

If the IPSec SA is established between the terminal 1 and the P-CSCF1, the P-CSCF1 sends the parameters for establishing the SA between the P-CSCF1 and the terminal 1 to the P-CSCF2 through the established session, and the P-CSCF1 collects the charge. The function (CCF) sends billing information.

If the IPSec SA is not established between the terminal 1 and the P-CSCF1, the P-CSCF1 sends the authentication parameter to the P-CSCF2 through the established session, and the P-CSCF1 sends the charging information to the CCF.

5) If the P-CSCF2 obtains the parameters for establishing the SA, the integrity of the IPSec ESP encapsulated message content and the encrypted payload decryption are performed based on the parameters of the IPSec SA;

If the P-CSCF2 does not obtain the parameters of the IPSec SA, the handover request message is authenticated based on the authentication parameter, where the authentication is omitted from the standard authentication process of the IMS, and the process of obtaining the authentication data to the HSS is omitted, and the signaling is shortened. The face delay is faster than the prior art IMS standard authentication process.

If the integrity verification and decryption are successful, or the message authentication is successful, the next process is continued, otherwise the handover failure response is returned to the terminal 1. 6) The P-CSCF2 sends a message to the SPDF2 according to the initiated handover request information after decoding, and requests the reserved resource. The SPDF2 further controls the SBC2 to establish the media connection of the destination user terminal address to the switching destination side SBC2 through the H.248 interface.

7) P-CSCF2 initiates a formal handover request to P-CSCF1.

8) After receiving the formal handover request, P-CSCF1 sends a message to SPDF1, which is passed by SPDF1.

The H.248 protocol controls the SBC1 media stream to be redirected, adapted, and transcoded. The event charging information may be further sent to the CCF to carry the switching identifier.

9) The P-CSCF1 sends a message to the terminal 1 to tear down the original session connection between itself and the terminal 1, and at the same time indicates to the P-CSCF2 that the handover has been completed.

10) The P-CSCF2 sends a handover complete message to the terminal 1, indicating that the handover procedure has been completed. The charging information is sent to the CCF, and the switching identifier is carried.

After the handover is successful, the P-CSCF2 will transmit all the interaction messages between the terminal and the network, such as Update, Reinvite, Info, etc., on the established handover session with the P-CSCF1 until the terminal side session ends, P-CSCF2 End the session with P-CSCF1. That is, for the signaling plane, the terminal 1 interacts with the network side through the P-CSCF2->P-CSCF1; for the media plane, the terminal 1 interacts with the peer terminal 2 through SBC2->SBC1.

Figure 2 shows a signaling flow diagram based on the embodiment shown in Figure 1. When the terminal 1 and the terminal 2 are in a call, the terminal 1 wants to switch from the handover source packet domain, that is, the packet domain access network 1, to the handover destination packet domain, that is, the packet domain access network 2, and access the IMS network by switching the destination packet domain.

Step 1. The terminal 1 detects the network signal strength, and determines to reattach from the current access aggregation node Nodel of the handover source packet domain to the access aggregation node Node2 of the handover destination packet domain. The terminal 1 completes the authentication process of the access network in the network in which the packet domain accesses the network 2, and obtains the IP address and the address of the P-CSCF2 through the Dynamic Host Configuration Protocol (DHCP).

Step 2: The terminal 1 sends an Invite to initiate a handover request message to the P-CSCF2 to notify the P-CSCF2 to initiate a handover request. The RequestURI of the message fills in the address of the P-CSCF1, and the message carries the handover request, the switched SDP, and the user identifier. Information, the user identifier may be a user public identity (IMTI) or a user private identity (IMPU).

If the IPSec SA is established between the terminal 1 and the P-CSCF1 based on the IMS-based AKA protocol or other authentication mode, the terminal 1 enters information other than the user IMPU and the handover request indication based on the SA. The line is encrypted and encapsulated in the Invite message body and sent to the P-CSCF2 together with the plaintext cell such as the user IMPU and the security context request indication. The IP header sending and receiving port encapsulated in the message exchanged between the P-CSCF2 and the terminal 1 is independent of the SA between the original P-CSCF 1 and the terminal 1. The SA tunnel is bidirectional. The tunnel encapsulation packet is the packet between the terminal 1 and the P-CSCF1 protected by IPSec. The tunnel mode is shown in Figure 3. The unprimed portion of Figure 3 represents the plaintext portion; the portion with the background color represents the IPSec ESP encryption/integrity protection portion.

If the IPSec SA is not established between the terminal 1 and the P-CSCF1, the Invite message sent by the terminal 1 to the P-CSCF2 is directly sent in plain text. In this case, the P-CSCF2 is required to authenticate the validity of the Invite message from the terminal.

Step 3: The P-CSCF2 sends an Invite message to the P-CSCF1, where the message carries the request security context request and the user IMPU identifier.

Step 4: The P-CSCF1 obtains the security context data of the terminal according to the user's IMPU and the security context request indication in the Invite message, and sends the security context data to the P-CSCF2 through the Info or 183 message.

Step 5: If the terminal has established an SA before the handover, the P-CSCF2 directly attempts to perform integrity verification and decryption;

If the terminal does not establish an SA before the handover, the P-CSCF2 directly initiates a 401 challenge, and initiates a legality authentication for the Invite to initiate the handover request message, as shown by the dotted line in step 5 of FIG. The authentication initiated by the Invite handover request message relative to the IMS standard authentication process omits the process of obtaining the authentication data to the HSS, shortening the signaling plane delay, and is faster than the prior art IMS standard authentication process. .

If the integrity verification and decryption succeeds, or the message authentication succeeds, the next process is continued, otherwise the handover failure response is returned to the terminal 1. In this example, it is assumed that the decryption or message authentication is successful, and the subsequent steps are continued.

Step 6: The P-CSCF2 sends a Diameter-AAR message to the SPDF2, and uses the switched SDP to apply for QoS reservation resources and security control. The message carries the address of the terminal 1 in the handover destination packet domain and the switched SDP information. The SDP information includes IP address, port, and media description information. SPDF2 further controls the SBC2 to perform security gating, QoS policy and NAT traversal through H.248. This step will complete the media stream connection between the terminal 1 and the handover target network SBC2.

So far, the terminal 1 establishes a media stream connection by switching the destination packet domain, that is, the packet domain 2 and the SBC2. Step 7: The P-CSCF2 sends an INFO message to the P-CSCF1 to initiate a formal handover request, where the message carries information such as a handover request, a switched SDP, and a user's IMPU. And sending event charging information to the CCF, carrying the switching identifier.

Step 8. After receiving the INFO message, that is, the formal handover request, the P-CSCF1 sends event accounting information to the CCF, carrying the handover identifier. At the same time, P-CSCF1 initiates security gating, QoS policy control and NAT traversal command to SPDF1 through Diameter message; SPDF1 combines local policy and received P-CSCF1 control information to determine security gating and QoS policy, and controls SBC2 according to H.248 message. The corresponding policy executes reserved resources.

SPDF1 controls SBC1 to perform the following policy, and reserves the media resources according to the switched SDP, and keeps the terminal 2 address sent to the terminal 1 to change the media stream of the SBC1 before switching, and establish the terminal 1 before switching.

The RTP media stream connection between SBC1 and the switched SBC2 address.

If the bandwidth, coding, and pre-switching of the media information after the handover are inconsistent, the P-CSCF1 carries the voice/video codec and the rate adaptation control parameter in the Diameter message in step 8.

SPDF1 controls the SBC1 with H.248 to perform the necessary media layer bandwidth adaptation and transcoding.

Step 9. The P-CSCF1 sends a 200 OK message to the P-CSCF2, indicating that the handover process has succeeded. The charging information is sent to the CCF, and the switching identifier is carried.

Step 10: The P-CSCF2 controls the SBC2 update session in the destination packet domain access network through the SPDF2 control to change the IP address information of the SBC 1 in the access source packet domain access network, thereby establishing

RTP media stream connection between SBC1 and SBC2.

So far, switching the source packet domain access network to the SBC1 and switching the destination packet domain access network

A media stream connection is established between SBC2.

Step 11, ? 80? 2? The 80?1 sends an 80 ^> 1^0 message indicating that the switching process is complete. Step 12: The P-CSCF2 sends a 200 OK message to the user terminal 1, and finally indicates that the handover is successful. Step 13: The P-CSCF1 sends a BYE message to the terminal 1, and removes the connection between the terminal 1 and the P-CSCF1. After the handover succeeds, the P-CSCF2 will transmit all the handover sessions established between the P-CSCF1 and the P-CSCF1. The interaction message between the terminal and the network (such as Update, Reinvite, Info, etc.) will be forwarded to the other end of the communication session, such as terminal 2, in B2BUA mode until the user side session ends; between P-CSCF2 and P-CSCF1. The session ends with BYE. So far, for the signaling plane, the terminal 1 interacts with the network side through P-CSCF2->P-CSCF1; for the media plane, the terminal 1 interacts with the opposite end, that is, the terminal 2 through SBC2->SBC1. It can be seen that the signaling flow of the interaction between the terminal 1 and the network does not need to pass through the S-CSCF and the SIP AS of the IMS core network, thereby improving the switching efficiency of the multimedia real-time session. In addition, in the handover process, when the user network interface (UNI) has started the IPSec security alliance, the terminal 1 can directly reuse the existing one after roaming from the handover source packet domain access network to the handover destination packet domain access network. The IPSec security association does not need to re-establish the security association. The switching speed can be further improved.

Specific implementation manner 2: The terminal that crosses the packet domain handover is accessed from the same P-CSCF.

FIG. 4 is a flow chart showing cross-packet domain switching signaling of a terminal accessing from the same P-CSCF according to the first embodiment of the present invention. The terminal 1 and the terminal 2 are in a call, and the terminal 1 switches from the packet domain access network 1 to the packet domain access network 2 to access the IMS network.

Step 1. The terminal 1 detects the network signal strength, and determines to reattach from the current access aggregation node Nodel of the handover source packet domain to the access aggregation node Node2 of the handover destination packet domain. The terminal 1 completes the authentication process of the access network in the network in which the packet domain accesses the network 2. The IP address and the address of the P-CSCF are obtained by the DHCP, and the P-CSCF address is the same as the original P-CSCF address.

Step 2: The terminal 1 sends an Invite to initiate a handover request message to the P-CSCF to initiate a handover request to the P-CSCF, and the RequestURI fills in the address of the P-CSCF, where the message carries the handover request indication, the switched SDP, and the user identifier. The user ID can be IMPI or IMPU.

If the IPSec SA is established between the current terminal 1 and the P-CSCF, the terminal 1 still directly uses the IPSec SA to perform integrity and privacy protection on the Invite message and subsequent messages. If the current terminal 1 and the P-CSCF are not yet If an IPSec SA is established, the Invite message will be sent to the P-CSCF in plain text.

Step 3: The P-CSCF obtains the security context data of the user according to the user IMPU.

If the handover request message indicates that the IPSec SA has been established between the terminal 1 and the P-CSCF, the P-CSCF performs integrity check and decryption on the handover request message based on the IPSec SA bound to the user. The following steps, otherwise returning the handover failure response directly to the terminal 1;

If the handover request message indicates that the IPSec SA has not been established between the terminal 1 and the P-CSCF, the P-CSCF initiates a 401 challenge to the terminal based on the user authentication information, and verifies the response (SRES) of the user terminal, as shown in FIG. The dotted line of 3 is shown. If the verification is passed, continue with the following steps, otherwise the handover failure response is directly returned to the terminal 1. Here, the authentication initiated by the Invite message is relative to the standard authentication process of IMS. The process of obtaining the authentication data by the HSS is omitted, and the signaling plane delay is shortened, which is faster than the prior art IMS standard authentication speed.

In this example, it is assumed that the decryption or message authentication is successful, and the subsequent steps are continued.

Step 4: The P-CSCF sends a Diameter-AAR message to the SPDF2, and applies the QoS reserved resource and security control by using the switched SDP. The message carries the address of the terminal 1 in the handover destination packet access network type and the SDP after the handover. information. SPDF2 further performs security gating, QoS policy and NAT traversal through H.248 control SBC2, which completes the media stream connection between terminal 1 and SBC2 in the handover target packet domain. Establish a media stream connection.

Step 5: The P-CSCF sends a Diameter-AAR message to the SPDF1, and the SPDF1 determines the security gating and the QoS policy according to the local policy and the received P-CSCF control information, and controls the SBC1 to perform reserved resources according to the corresponding policy by using the H.248 message.

The SPDF1 controls the SBC1 to perform the following policy, and reserves the media resources according to the switched SDP, keeps the media stream of the pre-SBC before the terminal 2 sends the address to the terminal 1, and establishes the address between the pre-switch SBC1 and the switched SBC2 address. RTP media stream connection.

If the bandwidth, coding, and pre-switching of the media information after the handover are inconsistent, the P-CSCF will carry the voice/video codec and rate adaptation control parameters in the Diameter message in step 5, and control the SBC1 by H.248 through SPDF1. Perform the necessary media layer bandwidth adaptation and transcoding.

Step 6. The P-CSCF sends a 200 OK message to the terminal 1, and finally indicates that the handover is successful.

So far, a media stream connection is established between SBC1 and SBC2.

Step 7: The P-CSCF sends a BYE message to the terminal 1, and disconnects the session between the handover source packet domain of the terminal 1 and the P-CSCF, and establishes a new session and communication peer between the handover destination packet domain of the terminal 1 and the P-CSCF. The B2BUA association relationship between the sessions; after the handover succeeds, all the interaction messages (such as Update, Reinvite, Info, etc.) of the P-CSCF and the terminal 1 in the handover destination side session are forwarded to the communication by the P-CSCF through the B2BUA mode. The other end of the session is terminal 2 until the user side session ends.

So far, for the signaling plane, the terminal 1 interacts with the network side through the P-CSCF; for the media plane, the terminal 1 interacts with the opposite end, that is, the terminal 2 through SBC2->SBC1. For the first embodiment, the SBC of the switching source packet domain access network may serve as a natural anchor point of the terminal 1 connected to the network side media bearer or the session peer media stream, because the switching source packet domain and the handover destination packet domain are The SBC establishes a media stream connection under the control of the P-CSCF and the SPDF. Therefore, the user plane media stream switching process across the packet domain access network is completely transparent to the called side, and there is no need to notify the peer to update the SDP through Reinvite, and the Reinvite is considered to be the main The B2BUA AS triggered in the SIP session of the called user is truncated; therefore, the embodiment has better value-added service integration capability than the VCC/MSC scheme recommended by the 3GPP standard.

In addition, in the first embodiment, by switching the SBC of the source packet domain access network, a branch switch connection between the switching source side and the switching destination side media stream in the circuit domain switching can be realized, thereby making a shorter handover delay possible. Embodiment 2: The packet domain access network on the switching source side is not deployed with an SBC, and the access network bearer control adopts a policy and charging rule function (PCRF) model defined by the 3GPP, that is, the P-CSCF controls the packet access convergence layer node through the PCRF. (such as GGSN, ASN-GW, BRAS, etc.) complete the bearer layer resource control including QOS management and security control. All media streams of the user session pass through the packet access aggregation layer node (such as GGSN, ASN-GW, BRAS). Wait).

FIG. 5 is a schematic diagram of cross-packet domain switching of terminals accessed by different P-CSCFs according to Embodiment 2 of the present invention. In this example, the terminal 1 roams from the packet domain access network 1, that is, the handover source packet domain to the packet domain access network 2, that is, the handover destination packet domain, where the single-dotted line indicates the original media stream, and the double-dotted line indicates the new media stream after the handover. The black solid line indicates session signaling. The implementation process of cross-packet domain switching is as follows:

2) The terminal 1 directly sends a handover request message to the P-CSCF2 to request to initiate the handover process. The RequestURI of the message fills in the address of the P-CSCF1, and the main carried cell in the message includes: a handover request indication, a switched SDP, and a user. Logo, etc. The SDP describes information such as the source IP address, port, destination IP address, port, and media type of the user media stream.

If the IPSec SA is established between the terminal 1 and the P-CSCF1 based on the IMS AKA protocol or other authentication mode, the user identity and handover in the originating handover request message sent by the terminal 1 to the P-CSCF2 The request indication is sent as plaintext without encryption, and the other part is included in the encrypted channel. The SA tunnel is bidirectional. The packet encapsulated by the tunnel is a packet between the terminal 1 and the P-CSCF1 protected by IPSec.

3) After receiving the handover request message from the terminal 1, the P-CSCF2 learns that the handover has occurred in the terminal 1 through the user identifier and the handover indication in the plaintext portion, and then the P-CSCF2 further sends a handover request message to the P-CSCF1 to obtain the P. - Security context data between CSCF1 and terminal 1.

4) The P-CSCF1 obtains the security context data of the user according to the IMPU of the terminal, and sends the data to the P-CSCF2, and the security context data may include parameters for establishing an SA between the P-CSCF1 and the terminal 1, and/or an authentication parameter.

If the IPSec SA is established between the terminal 1 and the P-CSCF1, the P-CSCF1 sends the parameter for establishing the SA between the P-CSCF1 and the terminal 1 to the P-CSCF2 through the established session, and the P-CSCF1 sends a report to the CCF. Fee information.

If the P-CSCF2 does not obtain the parameters of the IPSec SA, the handover request message is authenticated based on the authentication parameter, where the authentication is omitted from the standard authentication process of the IMS, and the process of obtaining the authentication data to the HSS is omitted, and the signaling is shortened. The face delay is faster than the prior art IMS standard authentication.

If the integrity verification and decryption succeeds, or the message authentication succeeds, the next process is continued, otherwise the handover failure response is returned to the terminal 1.

6) The P-CSCF2 sends a message to the PCRF2 according to the initiated handover request information after decoding, and requests to reserve resources, and then the PCRF2 controls the handover destination side packet access aggregation node such as GGSN, ASN-GW, BRAS, etc. to complete resource reservation. And policy control.

7) P-CSCF2 initiates a formal handover request to P-CSCF1. 8) After receiving the formal handover request, the P-CSCF1 negotiates the SDP information of the terminal 1 and the SDP information of the terminal 2 after the handover, and returns the SDP information after the negotiation to the P-CSCF2. And the event charging information can be further sent to the CCF.

9) The P-CSCF2 further informs the terminal 1 of the negotiated SDP description information through the established SIP session, and the terminal 1 establishes the session with the newly applied IP address and the terminal 2 at the moment on the handover destination packet domain access network. The unidirectional RTP media stream is connected, and the new media stream connection is connected to the audio and video codec.

10) The P-CSCF 1 initiates a Relnvite message to the terminal 2, and after receiving the Relnvite message, the terminal 2 performs negotiation between the received SDP and the local SDP, and further sends the negotiated SDP to the P-CSCF1, and The terminal 2 adjusts the media connection of the local end according to the negotiated SDP, completes the connection establishment of the bidirectional media stream of the terminal 1 in the switching destination packet domain access network IP address and the terminal 2, and the terminal 2 connects the newly created media stream with the audio and video codec. Connected.

So far, the two-way media stream connection is directly established between the terminal 1 and the terminal 2.

11) The P-CSCF1 then sends a teardown message to the terminal 1 to tear down the original session connection with the terminal 1, and at the same time indicates to the P-CSCF2 that the handover has been completed by the teardown response message.

12) P-CSCF1 then sends a message to PCRF1 to request the release of resources.

13) The P-CSCF1 notifies the P-CSCF2 that the handover is successful by releasing the resource response message, and the P-CSCF2 forwards the received release resource response message to the terminal 1, indicating that the handover process has been completed. Moreover, the P-CSCF 1 can further send charging information to the CCF, and carry the handover identifier.

After the handover is successful, the P-CSCF2 will transmit all the interaction messages between the terminal and the network, such as Update, Reinvite, Info, etc., on the established handover session with the P-CSCF1 until the terminal side session ends, P-CSCF2 End the session with P-CSCF1. That is, for the signaling plane, the terminal 1 interacts with the network side through P-CSCF2->P-CSCF1; for the media side, the terminal 1 directly interacts with the terminal 2.

Figure 6 shows a signaling flow diagram based on the embodiment shown in Figure 5. When the terminal 1 and the terminal 2 are in a call, the terminal 1 wants to switch from the handover source packet domain, that is, the packet domain access network 1, to the handover destination packet domain, that is, the packet domain access network 2, and access the IMS network by switching the destination packet domain.

Step 1, the terminal 1 detects the network signal strength, and determines to reattach from the current access aggregation node Node1 of the handover source packet domain to the access aggregation node Node2 of the handover destination packet domain. Terminal 1 is connected in the packet domain The authentication process of the access network is completed in the network of the network 2, and the IP address and the address of the P-CSCF2 are obtained through DHCP.

Step 2: The terminal 1 sends an Invite message to the P-CSCF2 to initiate a handover request to the P-CSCF2. The RequestURI of the message fills in the address of the P-CSCF1, and the message carries information such as a handover request, a switched SDP, and a user identifier. The user ID can be either IMPI or IMPU.

If the IPSec SA is established between the terminal 1 and the P-CSCF1 based on the IMS-based AKA protocol or other authentication mode, the terminal 1 encrypts information other than the user IMPU and the handover request indication based on the SA, and the user IMPU, The plaintext cells, such as the security context request indication, are encapsulated in the Invite message body and sent to the P-CSCF2. The IP header sending and receiving port encapsulated in the message exchanged between the P-CSCF2 and the terminal 1 is independent of the SA between the original P-CSCF1 and the terminal 1. The SA tunnel is bidirectional. The packet encapsulated by the tunnel is the packet between the terminal 1 and the P-CSCF1 protected by IPSec. The tunnel mode is shown in Figure 3. The unprimed portion of Figure 3 represents the plaintext portion; the portion with the background color represents the IPSec ESP Encryption/Integrity Protection section.

If the IPSec SA is not established between the terminal 1 and the P-CSCF1, the Invite initiated handover request message sent by the terminal 1 to the P-CSCF2 is directly sent in the plain text. In this case, the P-CSCF2 is required to authenticate the validity of the handover request of the user. .

Step 4: The P-CSCF1 obtains the security context data of the terminal from the local device according to the IMPU of the user in the Invite message and the security context request, and sends the message to the P-CSCF2 through the 183 message.

Step 5: If the terminal has established an SA before the handover, the P-CSCF2 directly attempts to perform integrity verification and decryption on the Invite message.

If the terminal does not establish an SA before the handover, the P-CSCF2 directly initiates a 401 challenge to initiate legality authentication for the Invite message, as shown by the dotted line in step 5 of FIG. The authentication initiated by the Invite message relative to the standard authentication process of the IMS omits the process of obtaining the authentication data to the HSS, shortening the signaling plane delay, and is faster than the prior art IMS standard authentication speed.

If the integrity verification and decryption are successful, or the message authentication is successful, the next process is continued, otherwise the handover failure response is returned to the terminal 1. In this example, it is assumed that the decryption or message authentication is successful, and the subsequent steps are continued. Step 6. The P-CSCF2 sends an INFO message to the P-CSCF1 to initiate a formal handover request to initiate the handover. The INFO message carries information such as a handover request, a switched SDP, and a user's IMPU. After receiving the INFO handover request message, the P-CSCF1 performs the negotiation of the SDP of the terminal 1 and the SDP of the terminal 2 after the handover, and sends a 200 OK message to the P-CSCF2, and carries the SDP information after the negotiation. The P-CSCF1 may further send event charging information to the CCF to carry the handover identifier.

Step 7: The P-CSCF2 sends a Diameter-AAR message to the PCRF2, where the message carries the SDP2 information of the terminal in the handover target side network, and the PCRF2 further controls the handover target side packet access aggregation node such as GGSN, ASN-GW, BRAS through the Diameter protocol. Etc., implement security gating, QoS policies.

There is no strict sequence between the above steps 6 and 7.

Step 8: The P-CSCF2 further informs the terminal 1 that the negotiated SDP information passes the 183 message of the established SIP session, and the terminal 1 establishes a single with the newly applied IP address at the moment on the handover destination packet domain access network. Connect to the RTP media stream and connect the new media stream connection to the audio and video codec.

So far, the terminal 1 establishes a one-way media stream connection with the terminal 2 by switching the destination packet domain, that is, the packet domain 2.

Step 9: The P-CSCF1 then sends a Relnvite message to the terminal 2 through the S-CSCF1, where the message carries the SDP information for switching the IP address of the destination packet domain access network, and after receiving the Relnvite message, the terminal 2 performs the received SDP and Negotiation between the local SDPs, sending 200 OK to the P-CSCF1, the 200 OK message can further carry the negotiated SDP information, and the terminal 2 adjusts the local media connection according to the negotiated SDP, and completes the terminal 1 switching. The destination packet domain access network IP address is connected to the bidirectional media stream connection of the terminal 2, and the terminal 2 connects the new media stream connection with the audio and video codec.

So far, the terminal 1 establishes a new bidirectional media stream connection with the terminal 2 by switching the destination packet domain, that is, the packet domain 2.

The above step 9 is only required after the step 6, and there is no strict sequence between the steps 7 and 8. Step 10: The P-CSCF1 sends a BYE message to the terminal 1, and the session between the terminal 1 and the P-CSCF1 is removed. Also establish P-( Step 11: The P-CSCF1 then initiates a Diameter AA /AAA command to the PCRF1. The PCRF1 controls the access aggregation node on the destination packet domain side to release the reserved resources of the original bearer connection through the Diameter AAR/AAA control.

Step 12: The P-CSCF1 sends a 200 OK message to the P-CSCF2, indicating that the handover process has been completed. And the charging information can be further sent to the CCF, and the switching identifier is carried.

Step 13: The P-CSCF2 sends a 200 OK message to the user terminal 1, and finally indicates that the handover is successful. After the handover is successful, the P-CSCF2 will transmit the interaction messages (such as Update, Reinvite, Info, etc.) between all terminals and the network on the established handover session with the P-CSCF1, and will forward the communication session to the communication session in the B2BUA mode. The other end is terminal 2 until the user side session ends; the session between P-CSCF2 and P-CSCF1 ends with Bye.

So far, for the signaling plane, the terminal 1 interacts with the network side through P-CSCF2->P-CSCF1; for the media plane, the terminal 1 directly interacts with the terminal 2. It can be seen that the signaling flow between the terminal 1 and the network does not need to pass through the S-CSCF and the SIP AS of the IMS core network, which improves the switching efficiency of the multimedia real-time tongue. In addition, in the handover process, when the user network interface (UNI) has started the IPSec security alliance, the terminal 1 can directly reuse the existing one after roaming from the handover source packet domain access network to the handover destination packet domain access network. The IPSec security association does not need to re-establish the security association. The switching speed can be further improved.

FIG. 7 is a flow chart showing cross-packet domain switching signaling of a terminal accessing from the same P-CSCF according to Embodiment 2 of the present invention. The terminal 1 and the terminal 2 are in a call, and the terminal 1 switches from the packet domain access network 1 to the packet domain access network 2 to access the IMS network.

Step 1. The terminal 1 detects the network signal strength, and determines to reattach from the current access aggregation node Nodel of the handover source packet domain to the access aggregation node Node2 of the handover destination packet domain. The terminal 1 completes the authentication process of the access network in the network in which the packet domain accesses the network 2, and obtains a new IP address and an address of the P-CSCF by the DHCP, and the P-CSCF address is the same as the original P-CSCF address.

Step 2: The terminal 1 sends an Invite to initiate a handover request message to the P-CSCF to initiate a handover request to the P-CSCF, and the RequestURI fills in the address of the P-CSCF, where the message carries the handover request indication, the switched SDP, and the user identifier. The user identity can be an IMPI or an IMPU. If the IPSec SA is established between the current terminal 1 and the P-CSCF, the terminal 1 still directly uses the IPSec SA to perform integrity and privacy protection on the Invite message and subsequent messages. If the current terminal 1 and the P-CSCF are not yet If an IPSec SA is established, the Invite message will be sent to the P-CSCF in plain text.

If the handover request message indicates that the IPSec SA has been established between the terminal 1 and the P-CSCF, the P-CSCF performs integrity check and decryption on the Invite message based on the IPSec SA bound to the user. If the decryption succeeds, the following continues. Step, otherwise returning the handover failure response directly to the terminal 1;

If the handover request message indicates that the IPSec SA has not been established between the terminal 1 and the P-CSCF, the P-CSCF initiates a 401 challenge to the terminal based on the user authentication information, and verifies the response of the user terminal, as shown by the dotted line of step 3 in FIG. Shown. If the verification is passed, continue with the following steps, otherwise return the handover failure response directly to the terminal 1. The authentication initiated by the Invite handover request message relative to the standard authentication process of the IMS omits the process of obtaining the authentication data to the HSS, shortening the signaling plane delay, and is faster than the prior art IMS standard authentication speed.

Step 4: The P-CSCF sends a Diameter-AAR message to the PCRF2, where the message carries the SDP information after the handover of the terminal 1, and the PCRF2 further controls the access aggregation node such as the GGSN, the ASN-GW, and the BRAS on the handover target packet domain side through the Diameter protocol. Etc., implement security gating, QoS policies.

Step 5: The P-CSCF then initiates a Relnvite message to the terminal 2, and after receiving the Relnvite message, the terminal 2 performs negotiation between the received SDP and the local SDP, and sends a 200 OK to the P-CSCF, where the 200 OK message is sent. The negotiated SDP information may be further carried, and the terminal 2 adjusts the media connection of the local end according to the negotiated SDP.

Step 6: The P-CSCF further informs the terminal 1 that the negotiated SDP information is 183 through the established SIP session, and completes the connection establishment of the two-way media stream of the terminal 1 in the switching destination network IP address and the terminal 2, and the terminal 1 will create a new media. The stream connection is connected to the audio and video codec.

So far, the terminal 1 establishes a new bidirectional media stream connection with the terminal 2 by switching the destination packet domain, that is, the packet domain access network 2.

Step 7. The P-CSCF sends a BYE message to the terminal 1, and the session between the terminal 1 and the P-CSCF is removed. Step 8: The P-CSCF then initiates a Diameter AA /AAA command to the PCRF1. The PCRF1 controls the access aggregation node on the destination packet domain side to release the reserved resources of the original bearer connection through the Diameter AAR/AAA control.

Step 9. The P-CSCF sends a 200 OK message to the terminal 1, and finally indicates that the handover is successful.

So far, for the signaling plane, the terminal 1 interacts with the network side through the P-CSCF; for the media plane, the terminal

1 Directly interact with terminal 2. After the handover succeeds, the P-CSCF establishes a B2BUA mapping relationship between the destination side session and the terminal end, and transparently transmits the interaction information between all terminals and the network side until the terminal side session ends.

For the second embodiment, since the media stream of the network side or the peer end of the network is directly connected to the media destination of the switching destination after the handover, the media stream does not have a loop, and the delay of the media in the mobile IP mode is small, which is beneficial to implement. Seamless multimedia session switching experience.

By applying the handover method of the cross-packet domain of the present invention, the multi-mode terminal does not need to perform the complete IMS network registration process again after switching to the handover destination packet domain, thereby effectively improving the speed of the cross-packet domain switching of the multimedia real-time session. Moreover, in the handover process, the signaling flow between the terminal and the network does not need to pass through the S-CSCF and the SIP AS of the IMS core network, thereby improving the switching efficiency of the multimedia real-time session. In addition, in the case that the user network interface (UNI) has started the IPSec security association, the terminal can directly reuse the existing IPSec security alliance after roaming from the switching source access network to the switching destination access network. Without the need to re-establish a security alliance, the switching speed can be further improved.

In addition, it should be noted that the callees in all the above embodiments are all described by using a terminal as an example. In actual applications, the called party may also be a server in the network, etc. For the present invention, the called side There are no strict restrictions on what kind of equipment.

Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by hardware, or can be implemented by means of software plus necessary general hardware platform, and the technical solution of the present invention. It may be embodied in the form of a software product, which may be stored in a computer readable storage medium (which may be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), including a number of instructions for making a computer device (may be A personal computer, server, or network device, etc., performs the methods described in various embodiments of the present invention. The present invention also provides a cross-packet domain switching system based on an IP multimedia subsystem, including a first terminal that has established a media stream connection, and the P-CSCF of the handover source packet domain of the first terminal and the handover destination packet domain P-CSCF and media connection control entity,

The P-CSCF of the handover source packet domain is configured to receive a handover request, establish a connection with the P-CSCF of the handover destination packet domain, so that the first terminal switches the P-CSCF of the destination packet domain, and switches the source packet domain. The P-CSCF interacts with the signaling on the network side; the media resource control operation is performed by the media connection control entity;

The media connection control entity includes: a first terminal switching SPDF and SBC of the destination packet domain, and switching SPDF and SBC of the source packet domain;

The first terminal switches the SPDF of the destination packet domain, and is configured to receive a message that the P-CSCF in the handover destination packet domain includes the SDP information of the first terminal after the handover, and control the SBC of the handover destination packet domain to perform resource reservation;

The first terminal switches the SPDF of the source packet domain, and is configured to receive a control command from the P-CSCF in the handover source packet domain, and control the SBC of the handover source packet domain to perform resource reservation;

The SBC of the handover destination packet domain is used to perform media reservation, and establish a media stream connection between the first terminal and the SBC of the handover destination packet domain;

The SBC of the handover source packet domain is used to perform the resource reservation, and keeps the media stream of the called source and the source packet domain SBC of the first terminal unchanged, and establishes the SBC and the handover destination packet domain of the handover source packet domain. SBC's media stream connection.

The media connection control entity includes: a PCRF and a packet access convergence node that switch the destination packet domain, and a PCRF and a packet access aggregation node that switch the source packet domain;

The PCRF of the handover destination packet field is configured to receive the SDP from the handover destination packet domain, and the SDP negotiated by the SDP and the called SDP after the handover by the first terminal, and control the handover destination packet access aggregation node to perform corresponding Resource control

The PCRF of the handover source packet domain is configured to receive a command for releasing the resource from the handover source packet domain P-CSCF, and control the packet access aggregation node in the handover source packet domain to release the reserved resource of the original bearer connection. The present invention also provides a cross-packet domain switching system based on an IP multimedia subsystem, including a first terminal that has established a media stream connection, and simultaneously serves as a handover source packet domain and a handover destination packet domain service of the first terminal. -CSCF, and media connection control entity,

The first terminal switches the SPDF of the destination packet domain, and is configured to receive a message that includes the SDP information of the first terminal after the handover from the P-CSCF, and controls the SBC of the handover destination packet domain to perform resource reservation; An SPDF of the source packet domain, configured to receive a control command from the P-CSCF, and control an SBC that switches the source packet domain to perform resource reservation;

The SBC of the handover source packet domain is used to perform the resource reservation, and keeps the media stream of the called source and the source packet domain SBC of the first terminal unchanged, and establishes the SBC and the handover destination packet domain of the handover source packet domain. The SBC's media stream is connected.

The PCRF of the handover destination packet domain is configured to receive a message that includes the SDP after the first terminal handover from the P-CSCF, and control a handover destination packet domain access aggregation node to perform corresponding resource control; The PCRF is configured to receive a command for releasing the resource from the P-CSCF, and control the packet access aggregation node of the handover source packet domain to release the reserved resource of the original bearer connection. The present invention also provides a P-CSCF, which serves to switch the source packet domain to the first terminal, and includes: The signaling control unit is configured to receive a handover request, establish a connection with the P-CSCF in the handover destination side packet domain, so that the first terminal implements the P-CSCF of the handover destination packet domain, the P-CSCF of the handover source packet domain, and the network side. Signaling interaction;

The media bearer control unit is configured to control the media connection control entity to perform a media resource control operation. The media connection control entity includes an SBC or a PCRF.

The present invention further provides a P-CSCF, serving a first terminal to switch a destination packet domain, comprising: a handover triggering unit, receiving an initiation handover request from the first terminal, and transmitting the handover request to the P-CSCF of the handover source packet domain;

The P-CSCF further includes: a parameter obtaining unit, configured to acquire a verification parameter from a P-CSCF that switches the source packet domain from the first terminal; and a verification unit, configured to perform verification on the received initiated handover request message according to the verification parameter After the verification is passed, the handover trigger unit is notified to be sent to the P-CSCF of the handover source side packet domain.

The above description is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications, equivalents, improvements, etc. made within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims

Rights request

A cross-packet domain switching method based on an IP multimedia subsystem, the first terminal has successfully established a media stream connection; when the first terminal moves from the handover source packet domain to the handover destination packet domain and the handover source of the first terminal When the proxy call session control function P-CSCF of the packet domain is different from the P-CSCF of the handover destination packet domain, the method further includes:

The method according to claim 1, wherein before the P-CSCF in the handover destination packet domain sends the handover request, the method further includes:

The P-CSCF of the handover destination packet domain receives a message for initiating a handover request from the first terminal, and verifies the message for initiating a handover request from the first terminal, and after the verification is passed, the handover source is further The P-CSCF of the packet domain sends a handover request.

The method according to claim 2, wherein if the first terminal establishes a security association with the P-CSCF of the handover source packet domain, the step of verifying includes:

The P-CSCF of the handover destination packet domain acquires security association parameters from the P-CSCF of the handover source packet domain, and applies the security association parameters to perform integrity verification and decryption on the initiated handover request, if integrity verification and If the decryption is successful, the verification is passed; otherwise the verification fails;

If the verification is passed, the handover request is sent to the P-CSCF of the handover source packet domain by tunneling.

The method according to claim 2, wherein if the first terminal does not establish a security association with the P-CSCF of the handover source packet domain, the step of verifying includes:

The P-CSCF of the handover destination packet domain obtains an authentication parameter from the P-CSCF of the handover source packet domain, and applies the authentication parameter to authenticate the initiated handover request. If the authentication succeeds, the verification succeeds. Otherwise the verification fails;

If the verification is passed, the handover request is sent to the P-CSCF of the handover source packet domain in a clear text manner.

The method according to claim 1, wherein before the P-CSCF in the handover destination packet domain sends a handover request to the P-CSCF in the handover source packet domain, the method further includes: switching the P of the destination packet domain The -CSCF controls the session border controller SBC of the handover destination side packet domain to perform resource reservation.

6. The method according to claim 5, wherein the switching source group domain

After receiving the handover request, the P-CSCF further includes: the P-CSCF of the handover source packet domain controls the SBC of the handover source packet domain to perform resource reservation.

The method according to claim 6, wherein the step of the first terminal establishing a new media bearer by the switched packet domain and the called party comprises:

After the SBC of the destination packet domain is switched to perform resource reservation, establishing a media stream connection between the first terminal and the switching destination packet domain SBC;

After the resource source reservation is performed in the handover source packet domain SBC, the media stream of the SBC in the source packet domain is switched between the called party and the first terminal, and the media stream connection between the handover source packet domain SBC and the handover destination packet domain SBC is established;

The first terminal establishes a new media bearer between the handover destination packet domain SBC, the handover source packet domain SBC, and the called party.

The method according to claim 1, wherein the P-CSCF of the handover source packet domain, after receiving the handover request, further includes:

The P-CSCF of the handover source packet domain negotiates the SDP information after the first terminal handover with the called SDP information; and transmits the negotiated SDP information to the P-CSCF of the handover destination packet domain; The P-CSCF of the side group domain controls the switching destination side packet access aggregation node to perform corresponding resource control by switching the destination packet domain policy and the charging rule function PCRF according to the negotiated SDP information.

The method according to claim 8, wherein the step of the first terminal establishing a new media bearer by the switched packet domain and the called party comprises:

The first terminal receives a message including the post-negotiation SDP information from the handover destination packet domain P-CSCF, and establishes a one-way media stream connection with the called party through the switched packet domain according to the negotiated SDP information. ;

The called party receives the first packet handover destination packet domain from the handover source packet domain P-CSCF The SDP information of the IP address is negotiated with the SDP information of the local device, and the media connection of the local end is adjusted according to the negotiated SDP.

The first terminal establishes a new media bearer directly with the called party by using the switched packet domain.

10. The method according to claim 9, further comprising:

The P-CSCF in the handover source packet domain sends a command indicating resource release to the PCRF in the handover source packet domain, and the PCRF in the handover source packet domain releases the original bearer connection according to the packet access aggregation node that controls the handover source packet domain according to the received command. Reserve resources.

The method according to claim 8 or 10, wherein the packet access aggregation node comprises at least a gateway GPRS support node GGSN, an access gateway ASN-GW or a broadband access server BRAS.

The method according to claim 7 or 10, wherein the step of implementing the first terminal to switch the P-CSCF of the destination packet domain, the P-CSCF of the handover source packet domain, and the signaling of the network side is implemented. Includes:

The P-CSCF of the handover source packet domain sends a message to the first terminal to tear down the original session connection between itself and the first terminal; and establishes between itself and the handover destination packet domain P-CSCF The back-to-back user agent association relationship is such that the first terminal sequentially implements signaling interaction with the network side through the handover destination packet domain P-CSCF and the handover source packet domain P-CSCF.

13. A cross-packet domain switching method based on an IP multimedia subsystem, the first terminal has successfully established a media stream connection; when the first terminal moves from the handover source packet domain to the handover destination packet domain and the handover source of the first terminal When the P-CSCF of the packet domain and the P-CSCF of the handover destination packet domain are the same P-CSCF, the method further includes:

The method according to claim 13, wherein the initiated handover request received by the P-CSCF is from the first terminal;

After receiving the message for initiating the handover request, the P-CSCF further includes: The message for initiating the handover request from the first terminal is verified, and after the verification is passed, the subsequent steps are performed.

The method according to claim 14, wherein if the first terminal establishes a security association with the P-CSCF in the switching source side packet domain, the step of verifying includes:

The P-CSCF obtains the security association parameter, applies the security association parameter to perform integrity verification and decryption on the initiated handover request, and if the integrity verification and decryption succeeds, the verification passes; otherwise, the verification fails;

If the verification is passed, the handover request is sent to the P-CSCF through a tunnel.

The method according to claim 14, wherein if the first terminal does not establish a security association with the P-CSCF in the switching source side packet domain, the step of verifying includes:

The P-CSCF obtains an authentication parameter, and applies the authentication parameter to authenticate the initiated handover request. If the authentication succeeds, the verification succeeds; otherwise, the verification fails;

If the verification is passed, the handover request is sent to the P-CSCF in a clear text manner.

The method according to claim 13, wherein the step of the P-CSCF controlling the switching destination network side to reserve resources for the switched media comprises:

The P-CSCF controls the SBC in the handover destination packet domain to perform resource reservation.

The method according to claim 17, further comprising: the P-CSCF controlling, by switching the source packet domain SPDF, the SBC in the handover source packet domain to perform resource reservation.

The method according to claim 18, wherein the step of the first terminal establishing a new media bearer by the switched packet domain and the called party comprises:

After the resource reservation of the SBC of the destination packet domain is performed, the media stream connection between the first terminal and the SBC of the switching destination packet domain is established;

After the SBC of the source packet domain is switched to perform resource reservation, the media stream of the called source packet domain SBC is kept unchanged, and the SBC of the handover source packet domain and the SBC of the handover destination packet domain are established. Stream connection

The first terminal establishes a new media bearer by the SBC of the handover destination packet domain, the SBC of the handover source packet domain, and the called party.

The method according to claim 13, wherein the step of controlling the switching destination network side to reserve resources for the switched media comprises: The P-CSCF sends a message carrying the SDP information of the first terminal to the PCRF in the handover destination packet domain, and the PCRF in the handover destination side packet domain controls the handover target side packet access aggregation node to perform corresponding resource control.

The method according to claim 20, wherein the step of the first terminal establishing a new media bearer by the switched packet domain and the called party comprises:

Receiving, by the first terminal, a message including the negotiated SDP information from the P-CSCF, and establishing, according to the negotiated SDP information, a unidirectional media stream connection with the called party by using the switched packet domain; The SDP information of the P-CSCF that includes the IP address of the destination packet in the first terminal is negotiated, and the received SDP information is negotiated with the SDP information of the local end, and the media connection of the local end is adjusted according to the negotiated SDP.

The first terminal establishes a new media bearer directly with the called party by switching the destination packet domain.

The method according to claim 21, further comprising: the P-CSCF sending a command indicating resource release to the PCRF of the handover source packet domain, where the PCRF of the handover source packet domain is controlled according to the received command The packet access aggregation node that switches the source packet domain releases the reserved resources of the original bearer connection.

A cross-packet domain switching system based on an IP multimedia subsystem, comprising: a first terminal that has established a media stream connection, a P-CSCF of the handover source packet domain of the first terminal, and a handover destination packet domain P-CSCF and media connection control entity,

The system according to claim 23, wherein the media connection control entity comprises: the first terminal switches the SPDF and SBC of the destination packet domain, and switches the SPDF and SBC of the source packet domain;

Transmitting, by the first terminal, an SPDF of the destination packet domain, for receiving the packet from the handover destination The P-CSCF in the domain includes a message of the SDP information after the first terminal is switched, and controls the SBC of the handover destination packet domain to perform resource reservation;

The SBC of the handover destination packet domain is configured to establish a media stream connection between the first terminal and the SBC of the handover destination packet domain after performing resource reservation;

The system according to claim 24, wherein the media connection control entity comprises: a PCRF and a packet access aggregation node that switch a destination packet domain, and a PCRF and a packet access aggregation node that switch the source packet domain;

The PCRF of the handover destination packet domain is configured to receive the SDP from the handover destination packet domain, and the SDP after the SDP is negotiated by the first terminal, and control the handover destination packet access aggregation node to perform corresponding Resource control

The PCRF of the handover source packet domain is configured to receive a command for releasing the resource from the handover source packet domain P-CSCF, and control the packet access aggregation node in the handover source packet domain to release the reserved resource of the original bearer connection.

A cross-packet domain switching system based on an IP multimedia subsystem, comprising: a first terminal that has established a media stream connection, and simultaneously serves a handover source packet domain and a handover destination packet domain of the first terminal; P-CSCF, and media connection control entity,

The system according to claim 26, wherein the media connection control entity comprises: a first terminal switching SPDF and SBC of a destination packet domain, and an SPDF of switching source packet domain And SBC;

The first terminal switches the SPDF of the destination packet domain, and is configured to receive a message that includes the SDP information of the first terminal after the P-CSCF is switched, and controls the SBC of the handover destination packet domain to perform resource reservation; An SPDF of the source packet domain, configured to receive a control command from the P-CSCF, and control an SBC that switches the source packet domain to perform resource reservation;

The system according to claim 26, wherein the media connection control entity comprises: a PCRF and a packet access aggregation node that switch a destination packet domain, and a PCRF and a packet access aggregation node that switch the source packet domain;

The PCRF of the handover destination packet domain is configured to receive a message from the P-CSCF that includes the SDP after the first terminal handover, and control the handover destination packet domain access aggregation node to perform corresponding resource control;

The PCRF of the handover source packet domain is configured to receive a command for releasing the resource from the P-CSCF, and control the packet access aggregation node of the handover source packet domain to release the reserved resource of the original bearer connection.

A proxy call session control function, the P-CSCF, serving the first terminal to switch the source packet domain, and the method includes:

The media bearer control unit is configured to control the media connection control entity to perform a media resource control operation.

30. The P-CSCF according to claim 29, wherein the media connection control entity comprises an SBC or a PCRF.

31. A proxy call session control function P-CSCF, serving a first terminal to switch a destination packet The domain is characterized by:

The P-CSCF according to claim 31, wherein the P-CSCF further comprises: a parameter obtaining unit, configured to: switch a P-CSCF of the source packet domain from the first terminal to obtain a verification parameter; And the method for verifying the received initiated handover request message according to the verification parameter, and after the verification is passed, notifying the handover trigger unit to send to the P-CSCF of the handover source side packet domain.