CN1874583A - Method for recovering service data when service rearrangement / rollback in system of dual attributes - Google Patents

Abstract

The present invention relates to a method for recovering service data during service switching/returning in a dual-homing system. In order to solve the problems in the prior art that established steady-state calls cannot be maintained normally when service switching/returning occurs, the method of the present invention The scheme is: during the call process, the softswitch center also sends corresponding additional information when sending the bearer operation to the media gateway registered to it; the media gateway also saves the additional information received by it in addition to carrying out the normal bearer operation. information; when the media gateway re-registers to another softswitch center after service switching/return occurs, it will report the call information containing additional information; the other softswitch center will receive additional information based on the The call information judges whether the current call is a steady-state call and performs corresponding processing, so as to ensure that the established steady-state call can be maintained normally, and for an unsteady-state call, the resources of the MGW and the peer entity can be released to avoid resource hanging.

Description

Method for recovering service data during service switching/rewinding in dual-homing system

technical field

The invention relates to a service switching or service reversing processing technology under a dual-homing system in a mobile communication network, and more specifically relates to a method for recovering service data during service switching/reversing in a dual-homing system.

Background technique

With the continuous development of mobile communication technology, the circuit domain core network of WCDMA and CDMA2000 networks has introduced the structure of separation of bearer and control, that is, the original mobile switching center (MSC) is divided into mobile soft switching center (MSCe) and media Gateway (MGW) two devices. For the convenience of description, the network and habits of CDMA2000 are used for description below, but the solution of the present invention is not limited to CDMA2000, and is also applicable to WCDMA and fixed networks.

As shown in FIG. 1 , dual-homing in the present invention means that one MGW can be connected to two MSCes, that is, it is subordinate to two MSCes. The two MSCes will work in the active/standby mode: under normal operation, the MGW can only register with one of the MSCe; when the MSCe fails, the MGW can register with the other MSCe, and the latter MSCe will continue to serve as the MGW Managed resources provide services.

It can be seen from Fig. 1 that under normal circumstances, MGW1 belongs to MSCe1, and MGW2 belongs to MSCe2. After dual-homing is configured, the standby MSCe of MGW1 is MSCe2, and the standby MSCe of MGW2 is MSCe1. In this way, the MSCe1 is configured with the resources of the MGW2 in addition to the resources of the MGW1, and normally the MSCe1 does not use the resources of the MGW2. The MSCe2 is configured with the resources of the MGW1 in addition to the resources of the MGW2. Normally, the MSCe2 does not use the resources of the MGW1. When working normally, MGW1 is registered on MSCe1, MGW2 is registered on MSCe2, the signaling forwarded by MGW1 is sent to its registered MSCe1, and the signaling forwarded by MGW2 is sent to its registered MSCe2. The BSC in Figure 1 is a base station controller.

When MSCe1 fails for some reason, the MGW belonging to it will register with MSCe2; at the same time, MSCe2 will detect heartbeat interruption and activate related resources, and take over the work of master MSCe1. The heartbeat mentioned here is usually called heartbeat detection, that is, the local end regularly sends a heartbeat message to the peer entity, and the peer end sends back a heartbeat response message after receiving it; the local end considers the peer end to be in a normal working state when it receives the heartbeat response message. If the heartbeat response message from the peer end cannot be received within a period of time, the peer end is considered to be in an abnormal state. When the failed MSCe1 returns to normal, its MGW1 re-registers with the MSCe1, and at the same time, the MSCe2 will detect the recovery of the heartbeat and finish taking over the work of the master MSCe1. In the above process, relative to MGW1, MSCe1 is the master and MSCe2 is the backup. If MSCe2 fails, compared to MGW2, MSCe2 is the master and MSCe1 is the backup

For the process that the standby MSCe takes over the work when the main MSCe fails, we call it service switching; for the process that the main MSCe recovers and takes over the work again, it is called service reversion. In the process of service switching and service reversion in the prior art, there are the following main problems: (1) take over the working MSCe (for service switching, it is the standby MSCe that takes over the work; for service reversion, it is the main MSCe that takes over the work) (2) There is no signaling connection relationship between the established call and other entities on the taking-over MSCe; (3) There is no established call user on the taking-over MSCe messages and other call information. The above-mentioned defects will lead to problems such as failure to normally process subsequent signaling, failure to carry out normal bearer operations, and loss of bills.

Taking the A port message as an example, for the traditional circuit domain structure, the signaling between the MSC and the BSC is carried on the No. 7 signaling, and the A port signaling protocol stack is shown in Figure 2. Among them, MTP is the Message Transfer Part (Message Transfer Part), SCCP is the Signaling Connection Control Part (Signalling Connection Control Part), and the A port protocol is carried on the SCCP.

After the softswitch structure is adopted, the control and bearer are separated, and the MSC is divided into two parts, namely the softswitch MSCe and the media gateway MGW. At this time, the A port signaling protocol stack is shown in Figure 3 (other forms of protocol stacks can also be used, However, this protocol stack is generally used for dual-homing), as can be seen from the figure, the No. 7 signaling between the MGW and the BSC is the circuit domain signaling, and the signaling between the MGW and the MSCe is carried on the IP (Internet Protocol, Internet Protocol). Among them, M2UA is the MTP2 User Adaptation Layer (SS7 MTP2-User AdaptationLayer), which is used to provide primitive communication services for MTP3 in the IP network and MTP2 at the edge of the network; SCTP is the Stream Control Transport Protocol (Stream Control Transport Protocol) . The M2UA method is equivalent to establishing an IP channel through which the MSCe uses the link on the MGW just like using the link at the local end.

For the A port protocol, the normal SCCP connection establishment process is shown in Figure 4.

(1) After SCCP A receives the service request of the upper-layer service, it will allocate its own connection reference, record the connection information of the upper-layer service, and initiate a connection establishment request (CR) to the peer end (SCCP B). There is a connection reference for the A terminal.

(2) After receiving the above connection establishment request, terminal B will allocate its own connection reference, record the connection reference of terminal A, and send the data to the upper-level business; after receiving the confirmation message of the upper-level business, record the connection information of the upper-level business , and send a connection confirmation (CC) to terminal A, in which the connection reference of terminal B and the connection reference of terminal A are included in the confirmation.

(3) After both parties A and B know the connection reference of the local end and the connection reference of the opposite end, the connection establishment is completed.

(4) When the subsequent upper-layer business wants to send data, it will send a message to SCCP, which contains the connection information of SCCP; SCCP then sends a message to the opposite end, which contains the connection reference of the opposite end; The connection reference in finds the data record of the local end, and sends the data to the upper-layer business module.

When the service switching occurs and the standby MSCe takes over the work, if there is no signaling connection information, the subsequent call information from the BSC will not be able to process the signaling because the corresponding connection reference cannot be found, and eventually the connection will be abnormally disconnected.

Taking the trunk side again as an example, in traditional technologies, ISUP or TUP is generally used for interconnection between MSC and PSTN. Here TUP is taken as an example for illustration, and ISUP is similar to it. TUP signaling is carried on the MTP, and its protocol stack is shown in Figure 5. After using softswitch, its protocol stack is shown in Figure 4.

When making a TUP trunk call, a TDM circuit is used to bear the traffic, and the circuit is marked with a unique circuit identifier CIC between the two entities, and the signaling between the two entities also depends on the CIC to establish a connection. When initiating a call, a circuit will be occupied, and the service table number will be recorded in the circuit table corresponding to the CIC, and an IAM message with CIC will be sent to the opposite end; after receiving the IAM message, the opposite end will occupy the circuit corresponding to the CIC, and allocate Business processing table, and record the business processing table number in the circuit table corresponding to the CIC. Subsequent call messages also carry the CIC, and call processing can be performed normally through the service connection table recorded in the corresponding circuit table.

When a service switchover occurs and the standby MSCe takes over the work, if there is no signaling connection information, for the TUP subsequent call information from the peer entity, the corresponding service connection table will not be found or the wrong service connection table will be found. The call is disconnected abnormally.

In order to solve the above-mentioned technical problems, the solution in the prior art is to make real-time backup of call information between the active MSCe and the standby MSCe. Its disadvantage is that the amount of backup data is very large, and the implementation cost is very high.

Contents of the invention

Aiming at the above-mentioned defects of the prior art, the present invention solves the problem that in the prior art, when service switching/returning occurs, the established steady-state call cannot be maintained normally, subsequent call signaling cannot be processed correctly, and the active and standby softswitches The method of real-time backup between centers will lead to the problem of high cost.

The technical solution adopted by the present invention to solve the technical problem is to provide a method for recovering service data during service switching/returning in a dual-homing system, which includes the following steps:

(S1) During the call process, when the softswitch center sends a bearer operation to its registered media gateway, it increases and sends corresponding additional information;

(S2) The media gateway performs a bearer operation, and saves the additional information it receives;

(S3) When service switching/returning occurs, the media gateway re-registers with another softswitch center, and reports the call information with the additional information;

(S4) The other softswitch center judges whether the current call is a steady-state call according to the received call information containing the additional information, and if so, restores the corresponding bearer according to the call information containing the additional information information, signaling connection information and user information.

In the step (S4) of the method of the present invention, if it is determined that the current call is an unsteady call, the softswitch center sends a bearer release message to the media gateway, and sends a disconnection message to the peer entity.

In the step (S4) of the method of the present invention, for a steady state call, its bill information is also restored.

In the method of the present invention, for the mobile communication system, the additional information may include signaling connection information and user information; the call information reported in the step (S3) includes: Context, additional information of Context, Termination, and the additional information of Termination; in the step (S4), the other softswitch center judges whether the current call is a steady state call according to the steady state flag in the additional information of Context.

In the step (S4) of the method of the present invention, if it is determined that the current call is a steady state call, then:

Restoring bearer information according to the Context and Termination;

Restoring signaling connection information with other entities according to the additional information of the Termination;

The user information and bill information are restored according to the additional information of the Context and the additional information of the Termination.

In the step (S3) of the method of the present invention, the call information is reported by means of flow control. The flow control method may be to report according to a fixed number of Contexts per unit time until all Context information is reported; or to evenly distribute the number of Contexts within a specified time to perform uniform reporting.

As can be seen from the foregoing technical scheme, in the present invention, since the corresponding additional information (which includes signaling connection information and user information, etc.) Report these information to the softswitch center when returning, so that the softswitch center can restore the corresponding bearer information, signaling connection information and user information according to the call information received by it that contains the additional information; thus making the established stable The state call can be held normally, the subsequent call signaling can also be processed correctly, and the bill can be issued normally. For non-stable calls, the bearer resources on the MGW, the resources of the softswitch center and the peer entity can be released, so as to avoid resource hanging.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and embodiment, in the accompanying drawing:

FIG. 1 is a schematic diagram of a dual-homing system;

Figure 2 is a schematic diagram of the protocol stack of the traditional A port message

Figure 3 is a schematic diagram of the protocol stack of the A port message after adopting the softswitch structure

Fig. 4 is a schematic diagram of the normal SCCP connection establishment process of the A port message;

Fig. 5 is a schematic diagram of a protocol stack of traditional TUP signaling;

Fig. 6 is a schematic diagram of the protocol stack of the TUP signaling after adopting the softswitch structure;

Fig. 7 is a schematic diagram of the call establishment process in a preferred embodiment of the present invention;

Fig. 8 is a schematic diagram of a switching/rewinding process in a preferred embodiment of the present invention.

Detailed ways

In the following specific embodiments, the network and habits of CDMA2000 are used to describe, but the solution of the present invention is not limited to CDMA2000, and is also applicable to WCDMA and fixed networks.

Since the media gateway (MGW) has the bearer information for call establishment, the bearer information can be restored through the interaction between the MGW and the MSCe (Mobile Soft Switch Center). However, it can be seen from the foregoing that it is not enough to restore only the bearer information, and if the signaling information cannot be restored, subsequent signaling cannot be processed correctly. Since there is bearer information on the MGW, signaling and user information can be further stored on the MGW. In this way, through the interaction between the MGW and MSCe, information such as bearer, signaling, user, and bill can be fully restored, and service switching and service switching can be realized. Smooth transitions during rewinding. Specifically, during the call establishment process, MSCe adds additional information (including signaling connection information, user information, etc.) to the bearer operation command to MGW; and the MGW saves these additional information.

When a switchover or switchback occurs, after the MGW registers with the new MSCe, it will report its stored bearer information, user information, and signaling information to the MSCe, and the MSCe will restore the information and rebuild the signaling and bearer of the call. , User bill information.

If there is no switchover or switchback, the additional information sent to the MGW is useless. In order to ensure that the normal business processing efficiency is not affected, the additional information should be as concise as possible. in,

(1) For the information that can be retrieved through static data configuration query, it can be omitted. For example, TUP, ISUP and other relays establish a signaling connection with the peer entity through CIC, and the CIC information can be obtained by querying static data through Termination reported by MGW , so its call information can be without CIC;

(2) For port A signaling, since the connection reference of the local end and the connection reference of the opposite end are dynamic data, they must be added to the additional information.

(3) Since the call list information needs to be recovered through data such as caller and called user information, connection time, etc., the corresponding data must also be added to the additional information.

When service switching or switching occurs, the MGW notifies the MSCe of the call information through a Notify message after the registration is completed. At the same time, the MGW reports the relevant Context, termination, and call additional information to the MSCe. When reporting information, flow control is used to report. There are two flow control methods: one is to report according to a fixed number of Contexts per unit time until all Context information is reported; the other is to distribute the number of Contexts evenly within a specified time. Report evenly.

Termination (endpoint) in the present invention is a logical entity on the MGW, which can be used to identify circuit resources on the MGW. Context (context) is used to indicate the connection relationship between endpoints. Among them, Context is applied for by MSCe and allocated by MGW. When two endpoints join the same Context, the default is to connect the two Terminations bidirectionally. That is to say, when the termination of the calling and called circuits are added to the same Context, the calling and called circuits are actually bidirectionally connected to the network.

After receiving the call information, the MSCe restores the bearer, signaling, and bill information for the steady-state call; for the unsteady-state call, it initiates a disconnection and sends a disconnection message to the peer entity to avoid resource hangup of the peer entity.

During specific implementation, the processing in the call establishment process is shown in FIG. 7 . Each step is described below.

Step 701, the calling user initiates a call, and the calling BSC sends a CM Service Req (CMService Req) message to the MSCe, which contains the calling user ID, called number, etc. This message is carried by the SCCP CR message, which also contains the connection reference of the BSC side.

Step 702, MSCe allocates the local connection reference, and allocates the circuit between MSCe and calling BSC (the circuit between MSCe and BSC is identified by CIC; between MSCe and MGW, this circuit is identified by Termination). Then, MSCe sends an add endpoint message (ADD) to MGW, which contains Termination information (the endpoint is the circuit with BSC), requesting to apply for a context (Context), and add Termination to the Context. In this embodiment, additional call information is added to the message: including the calling party information and the signaling connection relationship with the BSC (including the connection reference of the local end and the connection reference of the opposite end).

In step 703, the MGW allocates a Context, adds the corresponding Termination to the Context, and then returns a message to the MSCe, the MSCe records the corresponding Context, and the MGW records the aforementioned additional call information.

Step 704, MSCe sends an assignment request message (Assignment Request) to the calling BSC, requesting to establish a ground circuit and an air interface channel between the MSC and the BSC; this message is carried by the CC message of the SCCP, and has the connection reference of the MSC and the BSC side connection reference.

Step 705, for the case that the called party is a mobile subscriber, the MSC obtains the called location information from the HLR.

Step 706, if the HLR finds that the called party is in the MSC that initiated the request, then directly return a message indicating that the called party is in the MSC that initiated the location request;

Step 707: After the terrestrial circuit and the air channel of the calling BSC are established, the BSC sends an assignment complete message (Assignment Complete) to the MSCe; this message is carried in the SCCP DT message with the connection reference of the MSC.

Step 708, MSCe sends a paging message (Paging Request) to the called BSC; this message is carried by the connectionless message UDT message of SCCP.

Step 709: After the called party is paged, the called BSC sends a paging response message (PagingResponse) to the MSC. This message is carried in the SCCP CR message, with the connection reference on the BSC side.

Step 710, the MSCe allocates the connection reference of the local end, and allocates the circuit between the MSCe and the called BSC. The MSCe sends an Add Endpoint message (ADD) to the MGW, carrying the Context and called side Termination information just applied for. Additional call information is also added in the message: including the called user information, the signaling connection relationship with the BSC (local connection reference and peer connection reference).

In step 711, the MGW adds the Termination on the called side to the context, and then returns a message to the MSCe. The MGW records the aforementioned additional call information.

Step 712, MSCe sends an assignment message to the called BSC, requesting to establish a ground circuit and an air interface channel between the MSC and the BSC, with ringing parameters in the message to allow the called terminal to ring; this message is carried in the CC message of the SCCP, with The connection reference of the MSC and the connection reference of the BSC side.

Step 713: After the terrestrial circuit and the air interface channel are established, the called BSC sends an assignment complete message to the MSC; this message is carried in the SCCP DT message with the connection reference of the MSC.

In step 714, the MSCe sends a modify bearer message (Modify) to the MGW with the Termination on the calling side, and notifies the MGW to play a ring back tone to the calling side.

Step 715, after the MGW completes the operation, it returns a response message (Reply) to the MSCe.

Step 716: After the called party answers, the called BSC sends a CONNECT message to the MSCe; this message is carried in the DT message of the SCCP and carries the connection reference of the MSCe.

Step 717, MSCe sends a modify bearer message (Modify) to the MGW with the termination on the calling side, instructing the MGW to stop playing the ring back tone to the calling side, and connect the calling and called terminations to the network in both directions. Additional call information is added to the modified bearer message: including caller and called user information, connection time, steady-state flag, and the like.

Step 718, the MGW returns a response message (Reply) to the MSCe.

In the above steps, in addition to carrying out the normal bearer operation, the MGW also records the additional call information in the related message for use during service switching or switching.

The processing procedure when service switching or service reversing occurs is shown in FIG. 8 . in,

In step 801, the MGW sends a re-registration message to the MSCe.

Step 802, MSCe returns a registration response message.

Step 803, after receiving the registration response message, the MGW performs flow control to report the call information, that is, sends a bearer and call related information notification. Wherein, the MGW reports information according to the Context, and the reported content includes: Context, additional information of the Context, Termination, additional information of the Termination.

Step 804, after receiving the reported information, the MSCe performs differentiated processing according to the steady-state flag in the additional information of the Context, and sends a corresponding notification response to the MGW:

(1) For a call in a steady state, restore the bearer information according to Context and Termination; restore the signaling connection information with other entities according to the additional information of Termination; restore user information and bill information according to the additional information of Context and Termination .

(2) For calls that are not in a steady state or with incomplete information, send a bearer release message to the MGW, and send a disconnection message to the peer entity, so as to avoid resource hangup of the peer entity.

It can be seen from the above-mentioned embodiments that, through the method of the present invention, when a service switching or service reversing occurs between the active and standby MSCe, the established steady-state call can be maintained normally, and the subsequent call signaling can also be correctly processed, and can be sent out normally. bill. For an unsteady call, the resources of the MGW and the peer entity can be released to prevent resources from hanging.

Attached table: Abbreviations used in this article English abbreviations English meaning Chinese meaning AMSC Anchor MSC Initial MSC BSC Base Station Control base station controller CDMA Code Division Multiple Access CDMA CIC Circuit Identification Code Circuit ID GCI Global Cell Identify GCI IAM Initial Address Message start address message ISUP ISDN User Part ISDN User Section LAC Location Area Code location area code MDN Mobile Directory Number Mobile Station Directory Number MGW Media GateWay media gateway MIN Mobile Identification Number mobile identification number MS Mobile Station mobile station MSC CDMA Mobile Switch Center CDMA Mobile Switching Center SCCP Signaling Connection and Control Part Signaling Connection Control Section SDP Session Description Protocol Session Description Protocol TUP Telephone User Part Telephone User Section TMD Time Division Multiplex(ing) time division multiplexing VLR Visitor Location Register Visitor Location Register WCDMA Wideband CDMA wideband code division multiple access

Claims (8)

1, switching services in a kind of double attaching system/method of recovery business datum when refunding is characterized in that, may further comprise the steps:

(S1) in calling procedure, when soft switch center sends the carrying operation in the media gateway to its registration, increase the transmission corresponding additional information;

(S2) media gateway is carried operation, and preserves the described additional information that it is received;

(S3) switching services/when refunding, described re-registering media gateway arrives another soft switch center, and reports the call information that has described additional information when taking place;

(S4) described another soft switch center is according to its call information of receiving that comprises described additional information, judge whether current calling is that stable state is called out, if then recover corresponding beared information, signaling link information and user profile according to the call information that comprises described additional information.

2, method according to claim 1 is characterized in that, in described step (S4), is that unstable state is called out if judge current calling, and then described soft switch center sends the message of releasing bearing to media gateway, and sends clear message to the opposite end entity.

3, method according to claim 1 is characterized in that, in described step (S4), calls out for stable state, also recovers its ticket information.

4, method according to claim 1 is characterized in that, at mobile communication system,

Described additional information comprises signaling link information and user profile;

Comprise in the call information that in described step (S3), reports: the additional information of the additional information of Context, Context, Termination and Termination;

In described step (S4), described another soft switch center judges according to the steady state flag in the additional information of Context whether current calling is that stable state is called out.

5, method according to claim 4 is characterized in that, in described step (S4), is that stable state is called out if judge current calling, then:

According to described Context, Termination recovering bearing information;

According to the additional information recovery of described Termination and the signaling link information of other entity;

Recover user profile and ticket information according to the additional information of described Context, the additional information of Termination.

6, according to each described method among the claim 1-5, it is characterized in that, in described step (S3), adopt the mode of flow control to report described call information.

7, method according to claim 6 is characterized in that, described flow control mode is: report according to fixing Context number in the unit interval, report up to all Context information and finish.

8, method according to claim 6 is characterized in that, described flow control mode is: mean allocation Context number at the appointed time evenly reports.

Images