CN101426060A - Method, soft switching device and system for double home soft switch - Google Patents

Abstract

The embodiment of the present invention discloses a dual-homing softswitch method, softswitch equipment and system, wherein the method includes: detecting that the link from the first gateway to the user automatic branch exchange PABX is unreachable, and connecting the call information through the second gateway Send to the PABX. The embodiments of the present invention aim at adding a gateway to the PABX to improve the function of the dual-homing softswitch. When the gateway fails, the second gateway can process services normally without interrupting the service of the PABX.

Description

A dual-homing softswitch method, softswitch device and system

technical field

The invention relates to the field of communication technology, in particular to a dual-homing softswitch method, softswitch equipment and system.

Background technique

NGN (Next Generation Network, Next Generation Network) is a service-driven network. It adopts a comprehensive, open and integrated network architecture, and realizes relatively independent services through the complete separation of service and call control, call control and bearer. The system makes the business independent of the network.

NGN adopts the technology of separating call and bearer control, and the processing capability of network equipment has been greatly improved, which can handle more traffic and bear more business load. The softswitch device is responsible for controlling a large number of devices and call connections. It has very powerful processing capabilities and functions. The users that a softswitch device can support are on the order of millions of users or equivalent relays. This aspect simplifies the network for operators. The structure and level effectively reduce equipment cost and operation and maintenance expenditure, but on the other hand, it also brings security risks: when there is a problem or failure of the softswitch equipment, it will cause a wide range of communication failures and cause a very large impact on the entire network. Influence.

In the NGN network, "dual homing" is a way to prevent softswitch equipment downtime, softswitch equipment upgrade and maintenance, or unexpected disasters (such as fire in the equipment room, interruption of communication cables connected to the equipment room, abnormal power supply, etc.) The emergency communication disaster recovery mechanism, through the mutual backup between two sets of softswitch systems in different geographical locations, ensures that when one of the softswitch devices fails, the other softswitch device can All services are taken over to ensure the communication security of the network in times of emergency. The "dual-homing" mechanism is a unique security and disaster recovery technology in the NGN field, which is of great significance for dealing with emergencies.

In the process of realizing the present invention, the inventor finds that there are at least the following problems in the prior art:

Traditional dual-homing softswitch, when a softswitch device fails, MG (MediaGateway, media gateway) will take a certain amount of time to perform dual-homing switching, which will cause short interruption of PABX (Private Automatic Branch Exchange, user automatic branch exchange) business , and when the MG fails, the PABX service is interrupted and cannot be processed normally, and there is a single point of failure.

Contents of the invention

The embodiment of the present invention provides a dual-homing softswitch method, softswitch equipment and system, which improves the function of the dual-homing softswitch. When a softswitch fails and the MG performs dual-homing switching, the second gateway can still There is no need to wait for the call, and the business can be processed normally when the original MG fails.

Embodiments of the present invention provide a dual-homing softswitch method on the one hand, including:

Detect that the link to the private automatic branch exchange PABX by the first gateway is unreachable,

Send the connected call information to the PABX through the second gateway.

On the one hand, the embodiment of the present invention proposes a softswitch device for implementing dual-homing softswitch, including:

The first detection module is used to detect whether the link to the PABX through the first gateway is reachable;

The first sending module is configured to send the connection call information to the PABX through the second gateway when the detection result of the first detection module is that the link to the PABX through the first gateway is unreachable.

Another aspect of the embodiment of the present invention proposes a softswitch device for implementing dual-homing softswitch, including:

The second receiving module is used to receive the connection call information sent by the first softswitch device when the first softswitch device detects that the link to the PABX through the first gateway is unreachable;

The second sending module is configured to send the connected call information to the PABX through the second gateway.

Another aspect of the embodiments of the present invention proposes a system for implementing dual-homing softswitch, including a first gateway, a first softswitch device, and a second gateway,

The first softswitch is used to detect whether the link to the PABX through the first gateway is reachable;

The second gateway is configured to send call connection information to the PABX when detecting that the link to the PABX via the first gateway is unreachable.

The embodiments of the present invention aim at adding a gateway to the PABX to improve the function of the dual-homing softswitch. When the gateway fails, the second gateway can process services normally without interrupting the service of the PABX.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings without making creative efforts.

FIG. 1 is a flowchart of a method for providing a dual-homing softswitch according to Embodiment 1 of the present invention;

FIG. 2 is a flowchart of a method for providing a dual-homing softswitch according to Embodiment 2 of the present invention;

FIG. 3 is a schematic structural diagram of a system for implementing dual-homing softswitch provided by Embodiment 3 of the present invention;

FIG. 4 is a schematic structural diagram of a first softswitch device provided by Embodiment 3 of the present invention;

FIG. 5 is a schematic structural diagram of a second softswitch device provided by Embodiment 3 of the present invention;

FIG. 6 is a schematic structural diagram of a system for implementing dual-homing softswitch provided by Embodiment 4 of the present invention;

FIG. 7 is a schematic structural diagram of a system for implementing dual-homing softswitch provided by Embodiment 5 of the present invention;

FIG. 8 is a schematic structural diagram of a system for implementing dual-homing softswitch provided by Embodiment 6 of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

As shown in FIG. 1 , Embodiment 1 of the present invention provides a method for dual-homing softswitch, including the following steps:

Step s101, detecting that the link to the private automatic branch exchange PABX (Private Automatic Branch Exchange, private automatic branch exchange) by the first gateway is unreachable,

In step s102, the call connection information is sent to the PABX through the second gateway.

It also includes sending the connected call information to the second softswitch if it is detected that the link to the PABX through the first gateway is unreachable, and the second softswitch sends the connected call information to the PABX through the second gateway.

The embodiments of the present invention aim at adding a gateway to the PABX to improve the function of the dual-homing softswitch. When the gateway fails, the second gateway can process services normally without interrupting the service of the PABX.

The failure of the softswitch includes two possibilities; if the first softswitch fails completely, the PSTN will send all the calls to the PABX to the second softswitch; if the second softswitch is partially faulty, the first A softswitch and the first gateway, or the first gateway and the PABX, are only linked. At this time, the first softswitch will send the call connection information to the second gateway, or send it to the second gateway through the second softswitch.

As shown in Figure 2, Embodiment 2 of the present invention provides a method for dual-homing softswitch, including:

Step s201, send call information to the first softswitch device through the public switched telephone network PSTN (Public Switched Telephone Network, public switched telephone network), the call information includes trigger conditions. The trigger condition is used to trigger the application server to complete the corresponding task, and the call information is used to call the PABX.

Step s202, the first softswitch device triggers the application server AS (Application Server, application server) according to the trigger condition in the call information.

Step s203, the application server AS triggers the corresponding service according to the trigger condition of the first softswitch device, and after the AS processes the triggered service, it sends a completion instruction to the first softswitch device, indicating that the service triggered by the first softswitch device AS is done.

Step s204, after the first softswitch device receives the above-mentioned completion instruction, it processes the above-mentioned call information, generates connection call information, sends the connection call information to the PABX through the first gateway, and detects that the connection to the user through the first gateway is automatic. Whether the link of the private branch exchange PABX is reachable. By sending the connected call information to the PABX, the call from the PSTN to the PABX is realized. When sending the above call connection information to the PABX, in order to ensure that the call connection information reaches the PABX smoothly, after the first softswitch sends the call connection information to the first gateway, it needs to detect whether the PABX has received the call information sent by the first gateway. Continue call information.

If the detection result is that PABX does not receive the connection call information, then detect that the link to PABX is unreachable by the first gateway, and turn to step s205, if the detection result is that PABX receives the connection call information, detect the link to PABX by the first gateway If the road is reachable, go to step s207.

Step s205, if it is detected that the link from the first gateway to the PABX is unreachable, then the PABX has not received the call connection information, then sends the call connection information to the second softswitch, and notifies the PSTN to send the subsequent call information to the second softswitch. Second gateway. This step realizes the effect of dual-homing, that is, if the connection call information cannot be sent through the first softswitch device, it can be sent to the second gateway through the second softswitch device.

Or it is detected that the link from the first gateway to the PABX is unreachable, then the connection call information is sent to the second gateway, and then sent to the PABX through the second gateway.

Here, PABX has not received the connection call information sent by the first gateway, there are two situations:

The first kind of situation is, the first gateway that connects PABX and the first softswitch equipment has broken down, so the connection call information that the first softswitch equipment sends to PABX can't be sent successfully, this moment can pass through the first softswitch equipment The above-mentioned connection call information is sent to the second softswitch equipment, and sent to the PABX through the second gateway connected to the second softswitch equipment; or the above-mentioned connection call information can be sent to the second gateway through the first softswitch equipment, through the second Gateway sends to PABX.

The second situation is that the first softswitch device fails. The failure of the first softswitch includes two possibilities: one is the complete failure of the first softswitch. Under normal circumstances, the dual-homing softswitches, that is, the first softswitch and the second softswitch need to be configured with each other. The routing information of the other party, when the active home softswitch, that is, the first softswitch device fails, all calls will be bypassed to the backup home softswitch, that is, the second softswitch device. At this time, the backup home softswitch finds that there is a call routed to itself When receiving the connection call information; one is the partial failure of the first softswitch, that is, the link between the first softswitch and the first gateway, or the first gateway and the PABX, is just a link failure. At this time, the first softswitch will send the call The connection information is sent to the second gateway, or sent to the second gateway through the second softswitch device.

Then turn to step s206.

In step s206, the second softswitch sends the connected call information to the second gateway, and the second gateway sends the connected call information to the PABX. At this point, the second softswitch and the second gateway, as the backup home softswitch of the first softswitch and the first gateway, can replace the first softswitch and the first gateway, and continue to complete the purpose of calling the PABX.

Or the second gateway sends the connected call information to the PABX without passing through the second softswitch. At this time, the second gateway needs to be connected to the first softswitch device.

In step s207, if it is detected that the link to the PABX through the first gateway is reachable, and the PABX receives the connection call information, then the PABX continues to receive the subsequent connection call information sent by the first gateway.

After the call process ends, if the PSTN subsequently calls the PABX, it can pass through the first softswitch, and then send the subsequent connection call information to the PABX through the first gateway via the first softswitch.

When two sets of soft switch SS (Soft Switch, soft switch) equipment are in normal operation, they are mutually active and standby, and each controls its own trunk gateway, access gateway, terminal equipment, etc., and completes the call and service control functions of its own control domain. When one of the softswitches breaks down, the corresponding softswitches for mutual backup will be responsible for taking over the trunk gateway, access gateway and terminal equipment it controls, and all calls will be directed to the softswitches for mutual backup. The trunk gateway, access gateway, terminal equipment, etc. configure the address information of the active home softswitch and the standby home softswitch, and use H.248/MGCP/SIP and other protocols to detect with the active home softswitch. When the home softswitch is unreachable, it will automatically register with the standby home softswitch. The heartbeat mechanism of the SIP-I protocol is used between the two sets of softswitches to detect the survival status of the mutual backup softswitches, and configure the routing information of each other so that when a set of softswitches fails, the corresponding mutual backup softswitches The device will be responsible for taking over the trunk gateways, access gateways and end devices it controls.

After step s206, it also includes:

Sending subsequent call information to the first softswitch through the PSTN, sending subsequent call information to the second softswitch through the first softswitch, or sending subsequent call information to the second softswitch through the PSTN;

The second softswitch device triggers the application server according to the subsequent call information;

After receiving the subsequent connection call information replied by the application server according to the subsequent call information, the second softswitch device processes the subsequent connection call information, and sends the processed subsequent connection call information to the second gateway;

The second gateway sends subsequent connected call information to the PABX.

After the call process ends, if the PSTN subsequently calls the PABX, it can pass through the second softswitch, and then send the subsequent connection call information to the PABX via the second gateway.

As can be seen from the above specific embodiments, when the first softswitch device finds that the first gateway fails, it can send the information to be sent to the second softswitch device, and the second softswitch device can pass through the standby The second gateway sends the message to be sent to the PABX, thereby realizing a perfect dual-homing softswitch. In addition, when the first softswitch fails, it can also be switched to the second softswitch to pass the information to be sent through the first softswitch. The second gateway sends the message to the PABX. When the gateway performs dual-homing switching, the second gateway can still connect the call without waiting, and can process the business normally when the first gateway fails.

The embodiment of the present invention adopts adding a gateway for PABX, perfects the function of dual-homing softswitch, when a softswitch device breaks down (for example, the link failure of the first softswitch to the first gateway or PABX), dual-homing switching is performed , the first gateway and the second gateway can still connect the call, and when the first gateway fails, the second gateway can process the business normally without causing the interruption of the PABX service.

Embodiment 3 of the present invention provides a system for realizing dual-homing softswitch, as shown in FIG. 3 , including:

The first softswitch 310 is used to detect whether the link to the private automatic branch exchange PABX330 by the first gateway 320 is reachable;

The second gateway 350 is used to send the connection call information to the PABX 330 when detecting that the link to the PABX 330 through the first gateway 320 is unreachable.

The system also includes a second softswitch 340,

When detecting that the link to the PABX 330 by the first gateway 320 is unreachable, receive the connection call information sent by the first softswitch 310, and send the connection call information to the PABX 330 by the second gateway 350.

Wherein, the first softswitch 310 is used to send the call connection information to the PABX 330 by the first gateway 320, and detects whether the PABX 330 receives the call connection message;

If the detection result is that the PABX 330 has not received it, then it is detected that the link to the PABX 330 by the first gateway 320 is unreachable.

The first softswitch device 310 is used to send the connection call information to the PABX 330 by the first gateway 320, detect whether the link to the PABX 330 by the first gateway 320 is reachable, and detect whether the PABX 330 receives the call information by the first gateway 320 The call connection information sent, if the detection result is that the PABX330 does not receive the call connection information, then the call connection information is sent to the second softswitch 340;

The PSTN 360 sends call information to the first softswitch device 310, and the call information includes a trigger condition. The first softswitch device 310 triggers the application server AS 370 according to the trigger condition in the call information. Trigger condition, trigger corresponding business, after AS 370 finishes the business of this trigger, send completion indication to this first softswitch device 310, show that the business that the first softswitch device 310 triggers has been completed, and this first softswitch device 310 After receiving the above-mentioned completion instruction, the above-mentioned call information is processed, and the connection call information is generated.

Wherein, the second softswitch 340 can also be used to receive the connection call information sent by the first softswitch 310 through the PSTN 360.

Here, PABX 330 has not received the connection call information sent by the first gateway 320, there are two situations:

The first kind of situation is, the first gateway 320 that connects PABX 330 and the first softswitch 310 has broken down, can send above-mentioned connection call information to the second softswitch 340 by the first softswitch 310 this moment, pass The second gateway 350 connected with the second softswitch 340 sends it to the PABX 330.

The second case is that the first softswitch 310 fails. Under normal circumstances, between dual-homing softswitches, that is, between the first softswitch 310 and the second softswitch 340, each other’s routing information needs to be configured in advance. , when the active home softswitch, that is, the first softswitch 310 fails, all calls will go through the standby home softswitch, that is, the second softswitch 340. At this time, the standby home softswitch finds that there is a route to the active home softswitch When calling, receive the connection call information, and send the connection call information to PABX 330 through the second gateway.

The first softswitch device 310, as shown in Figure 4, includes:

The first detection module 311 is used to detect whether the link to the subscriber automatic branch exchange PABX 330 by the first gateway 320 is reachable;

The first sending module 312 is used to send the connection call information to the PABX 330 through the second gateway 350 when the detection result of the first detection module 311 is that the link to the PABX 330 through the first gateway 320 is unreachable.

The first sending module 312 is also used to send the connection call information to the PABX 330 by the first gateway 320;

The first detection module 311 is used to detect whether the PABX 330 receives the call connection information, and if the call connection information is not received, it detects that the link to the PABX330 by the first gateway 320 is unreachable.

The first detection module 311 detects that the link to the PABX 330 by the first gateway 320 is unreachable, and the first sending module 312 sends the connection call information to the second softswitch 340, which is passed by the second softswitch 340 The second gateway 350 sends the call connection information to the PABX 330.

The first softswitch device 310 also includes:

The first trigger module 313 is used to trigger the application server AS 370 according to the call information sent by the PSTN 360;

The first processing module 314 is configured to receive a completion indication replied by the triggered application server AS 370 after completing the triggered service, process the call information sent by the PSTN 360, generate connection call information, and notify the first sending module 312.

The first trigger module 313 is also used for notifying the public switched telephone network PSTN 360 to send subsequent call information to the second softswitch 340 when the link to the private automatic branch exchange PABX is unreachable through the first gateway.

If the detection result of the first detection module 311 is that the PABX 330 receives the connected call information, then continue to receive the subsequent connected call information sent by the first gateway 320.

Above-mentioned second softswitch device 340, as shown in Figure 5, includes:

The second receiving module 341 is used for receiving the connection call information sent by the first softswitch device 310 when the first softswitch device detects that the link to the private automatic branch exchange PABX 330 by the first gateway 320 is unreachable;

The second sending module 342 is configured to send the call connection information to the PABX 330 through the second gateway 350 .

As can be seen from the above specific embodiments, when the first softswitch 310 finds that the first gateway 320 fails, that is, it does not detect that the first gateway 320 sends the connected call information to the PABX330, it can send the connected call information that needs to be sent. The information is sent to the second softswitch 340, and the second softswitch 340 can send the message to be sent to the PABX330 through the standby second gateway 350, thereby realizing a perfect dual-homing softswitch. In addition, in the first When the softswitch 310 breaks down, it can also switch to the second softswitch 340 to send the information to be sent to the PABX330 through the second gateway 350. When the first gateway 320 and the second gateway 350 perform dual-homing switching, the second gateway Calls can still be continued without waiting, and when the first gateway fails, services can be processed normally.

The embodiment of the present invention adopts adding a gateway for PABX, perfects the function of dual-homing softswitch, when a softswitch device breaks down (for example, the link failure of the first softswitch to the first gateway or PABX), dual-homing switching is performed , the first gateway and the second gateway can still connect the call, and when the first gateway fails, the second gateway can process the business normally without causing the interruption of the PABX service.

As shown in FIG. 6, Embodiment 4 of the present invention provides a system for implementing dual-homing softswitch.

The difference from the third embodiment is that in this embodiment, the PSTN 360' is used to detect whether the first soft switch device 310' fails, and when the PSTN 360' detects that the first soft switch device 310' fails, it sends a report to the second soft switch device 310' The switching device 340' retransmits the call information, and after receiving the retransmitted call information from the PSTN 360', the second softswitch 340' triggers the AS 370', and after receiving the completion instruction replied by the AS 370', generates the connection call information , and send to the PABX 330' through the second gateway 350'.

Or the PSTN 360' sends the connected call information of the first softswitch 310' to the second softswitch 340', and the second softswitch 340' sends the connected call information to the PABX 330' through the second gateway 350'.

In this embodiment of the program, when the first softswitch 310' fails, the call information can be sent to the second softswitch 340' through the PSTN 360', and the second softswitch 340' and the second gateway 350' can maintain Business as normal.

The specific process is similar to the above-mentioned embodiment, and will not be repeated here.

As shown in Figure 7, Embodiment 5 of the present invention provides a system for realizing dual-homing softswitch. The difference from the system of dual-homing softswitch in Embodiment 3 is that the first softswitch device 310" can be connected to the first gateway. 320" and the second gateway 350", similarly, the second softswitch 340" can also connect the first gateway 320" and the second gateway 350". When it is detected that the first softswitch 310" or the first gateway 320" fails, the connection call information will be sent to the second softswitch 340" through the first softswitch 310", and the connection will be connected through the second gateway 350". Call information sent to PABX 330". When the first gateway 320" fails, the call connection information can be sent to the second soft switch device 340" through the first soft switch device 310", and the second soft switch device 340" will send the call connection information through the second gateway 350" to PABX.

The embodiment of the present invention adopts adding a gateway for PABX, perfects the function of dual-homing softswitch, when a softswitch device breaks down (for example, the link failure of the first softswitch to the first gateway or PABX), dual-homing switching is performed , the first gateway and the second gateway can still connect the call, and when the first gateway fails, the second gateway can process the business normally without causing the interruption of the PABX service.

As shown in Figure 8, in the dual-homing softswitch system provided by Embodiment 6 of the present invention, the first softswitch device 310"' can connect the first gateway 320"' and the second gateway 350"', similarly, the second softswitch The switching device 340"' can also connect the first gateway 320"' and the second gateway 350"'.

The difference between Embodiment 6-1 and Embodiment 5 is that there is no heartbeat signal between the first softswitch 310"' and the second softswitch 340"', and when the first gateway 320"' fails, it can pass through the second A soft switch device 310"' sends the connected call information to the second gateway 350"', at this time, the second soft switch device 340"' may not be used.

Embodiment 6-2 is still in accordance with the system connection method shown in Figure 8. The difference from Embodiment 6-1 is that in Embodiment 6-2, PSTN 360"' is used to detect the first softswitch device 310"' Whether it is faulty, when the PSTN 360"' detects that the first softswitch 310"' fails, it resends the call information to the second softswitch 340"', and the second softswitch 340"' receives the PSTN 360"' retransmission After sending the call information, trigger the AS 370"', and after receiving the completion instruction of the AS 370"' reply, generate the connection call information, and send it to the PABX 330"' through the second gateway 350"'.

Or the PSTN 360"' sends the connected call information of the first softswitch device 310"' to the second softswitch device 340"', and the second softswitch device 340"' sends the connected call information through the second gateway 350"' Give PABX 330''.

The specific process is similar to the above-mentioned embodiment, and will not be repeated here.

In the embodiment of the present invention, the softswitch detects whether the PABX has received the connection call information sent by the first gateway, and if it does not receive it, initiates link switching to the second softswitch or the second gateway. At this time, the softswitch has the initiative to select which link. Moreover, in the embodiment of the present invention, as long as the PABX is connected to two gateways, it is not required that one gateway must be connected to two softswitches for service backup. It is only a preferred embodiment of the present invention that one gateway is connected to two softswitches for service backup.

The embodiment of the present invention adopts adding a gateway for PABX, perfects the function of dual-homing softswitch, when a softswitch device breaks down (for example, the link failure of the first softswitch to the first gateway or PABX), dual-homing switching is performed , the first gateway and the second gateway can still connect the call, and when the first gateway fails, the second gateway can process the business normally without causing the interruption of the PABX service.

Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be realized by hardware, or by means of software plus a necessary general-purpose hardware platform. Based on this understanding, the technical solution of the present invention It can be embodied in the form of software products, which can be stored in a non-volatile storage medium (which can be CD-ROM, U disk, mobile hard disk, etc.), and include several instructions to make a computer device (which can be It is a personal computer, a server, or a network device, etc.) to execute the methods described in various embodiments of the present invention.

Those skilled in the art can understand that the drawing is only a schematic diagram of a preferred embodiment, and the modules or processes in the drawing are not necessarily necessary for implementing the present invention.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (13)

1, a kind of method of dual-homed soft switch is characterized in that, comprising:

Detection is unreachable to the link of automatic branch exchange PABX by first gateway,

By second gateway replay call information is sent to described PABX.

2, the method for claim 1 is characterized in that, described detection comprises to the link of PABX is unreachable by first gateway:

Send replay call information by first gateway to PABX, and detect described PABX and whether receive described replay call information;

If testing result is described PABX when not receiving, then detect unreachable to the link of PABX by first gateway.

3, method as claimed in claim 2 is characterized in that, described first gateway that passes through sends replay call information to PABX, is specially:

The call information that sends according to common exchanging telephone network PSTN triggers application server;

Receive the described application server that is triggered and finish the indication of finishing of replying after the business of triggering, the call information that described PSTN sends is handled, generate described replay call information;

Send described replay call information by described first gateway to described PABX.

4, method as claimed in claim 1 or 2 is characterized in that, described detection is unreachable to the link of PABX by first gateway, specifically comprises:

When first Softswitch or described first gateway fails, then detect unreachable to the link of PABX by first gateway.

5, method as claimed in claim 1 or 2, it is characterized in that, if detection is unreachable to the link of PABX by first gateway, replay call information is sent to second Softswitch, by second gateway described replay call information is sent to described PABX by described second Softswitch.

6, a kind of Softswitch is used to realize dual-homed soft switch, it is characterized in that, comprising:

Whether first detection module is used to detect by the link of first gateway to PABX and can reaches;

First sending module, the testing result that is used for when described first detection module is unreachable to the link of described PABX by first gateway, by second gateway replay call information is sent to described PABX.

7, Softswitch as claimed in claim 6 is characterized in that, described first sending module also is used for sending replay call information by first gateway to described PABX;

First detection module is used to detect described PABX and whether receives described replay call information, if do not receive described replay call information, then detects by first gateway unreachable to the link of PABX.

8, as claim 6 or 7 described Softswitch, it is characterized in that, first detection module detects by first gateway unreachable to the link of PABX, described first sending module sends to second Softswitch with replay call information, by second gateway described replay call information is sent to described PABX by described second Softswitch.

9, as claim 6 or 7 described Softswitch, it is characterized in that, also comprise:

First trigger module, the call information that is used for sending according to PSTN triggers application server;

First processing module is used to receive the described application server that is triggered and finishes the indication of finishing of replying after the business of triggering, and the call information that described PSTN sends is handled, and generates described replay call information, and notifies described first sending module.

10, a kind of Softswitch is used to realize dual-homed soft switch, it is characterized in that, comprising:

Second receiver module is used for when unreachable, receiving the replay call information that described first Softswitch sends to the link of PABX when first Softswitch detects by first gateway;

Second sending module is used for described replay call information is sent to described PABX by second gateway.

11, a kind of system is used to realize dual-homed soft switch, it is characterized in that, comprises first gateway, first Softswitch and second gateway,

Whether described first Softswitch is used to detect by the link of first gateway to PABX and can reaches;

Described second gateway is used for when unreachable, replay call information being sent to described PABX to the link of PABX when detecting by first gateway.

12, system as claimed in claim 11 is characterized in that, also comprises second Softswitch,

Be used for when unreachable, receiving the replay call information of first Softswitch transmission to the link of PABX, described replay call information sent to described PABX by second gateway when detecting by first gateway.

As claim 11 or 12 described systems, it is characterized in that 13, described first Softswitch is used for sending replay call information by first gateway to PABX, and detect described PABX and whether receive described replay call information;

If testing result is described PABX when not receiving, then detect unreachable to the link of PABX by first gateway.

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