CN100450298C - Method and device for roaming switching - Google Patents

Abstract

The invention discloses a roaming switching method, which is used to solve the problem in the prior art that the conversation may be interrupted for a long time when roaming switching occurs at one end of the conversation during the call continuation process. Including steps: A. When the call connection starts, determine the media resource server according to the current location of the calling terminal or the address of the P-CSCF that accepts the call, and establish a connection between the calling terminal and the media resource server with the IP address of the calling terminal. The first two-way connection is to establish a two-way connection between the called terminal and the media resource server with the IP address of the called terminal; B. When the calling terminal needs to be switched, it is established with the switching destination IP address of the calling terminal The two-way connection between the media resource server and the calling terminal is changed, and the first connection is changed to a one-way connection between the media resource server and the calling terminal to complete the handover.

Description

Method and device for roaming switching

technical field

The invention relates to the field of wireless networks, in particular to a roaming switching method, device and system in an IP-based voice network (VoIP network).

Background technique

In a VoIP network, the calling and called terminals are identified and addressed by IP addresses. However, the terminal may move during the conversation and roam to other IP networks with different network segment addresses. In this case, it is necessary to switch the IP address of the terminal on the switching side from the original network to the target network.

Existing technology 1: complete roaming handover through Mobile IP protocol.

The terminal assigns its own IP address in the home network. When the terminal leaves its home network, for example, roaming to network B, it will still use the IP address of the home network to communicate with the other party in the call, but it will obtain a care-of address (COA address) in the roaming network, and send to the home network in the home network The agent device (HA) registers the COA address. The calling party still sends IP data packets bearing voice to the home network, but these IP data packets are intercepted by the HA and forwarded to the COA address through the tunnel. If the COA address is the address of the mobile terminal in the roaming network, the IP data packet can directly reach the mobile terminal. If the COA address is the foreign agent device (FA) address in the roaming network, the IP data packet will be forwarded to the mobile terminal by the FA device.

However, during the handover process, when the HA does not receive the notification message from the handover destination network, and before the HA changes the destination address, it will not be able to intercept the peer data packet, causing the mobile terminal call to be temporarily interrupted. Since the location of the HA is relatively fixed, when the distance from the handover terminal to the HA is relatively long, the interruption time will be relatively long, which will bring a bad user experience to the user.

The second prior art: switching is performed at the application layer.

For example: the terminal roams to network B after leaving network A, and obtains a new IP address on network B. Afterwards, resend the Invite message to the other party through the application layer protocol with SIP signaling to notify the terminal of the calling party that its IP address has changed, and the IP data packet carrying the voice should be sent to the new IP address.

However, during the handover process, when the notification message about the change of the IP address has not arrived at the terminal of the other party, and before the terminal of the other party changes the sending destination address, the terminal at the switching side will not be able to receive the voice data packet sent by the terminal of the other party , resulting in a temporary interruption of the mobile terminal call. Since the distance between the two parties in the call is not fixed, when the distance between the two parties is relatively long, the interruption time will be relatively long, which will bring a bad user experience to the user.

Contents of the invention

The invention provides a roaming switching method, which is used to solve the problem in the prior art that a media resource server participating in a call is randomly selected when a roaming switch occurs at one end of a session during a call continuation process, resulting in a relatively high call interruption rate.

The invention also provides an IP-based voice network, which is used to determine the media resource server participating in the call, and use the media resource server to complete the switching.

A roaming handover method of the present invention comprises steps:

A. When the call connection starts, query the current location of the calling terminal through the network attachment subsystem, determine the media resource server closest to the calling terminal based on the current location of the calling terminal, or control the call session according to the agent accepting the call The address information of the functional device P-CSCF determines the media resource server closest to the address, and establishes a bidirectional first connection between the calling terminal and the media resource server with the IP address of the calling terminal, and uses the IP address of the called terminal The address establishes a two-way connection between the called terminal and the media resource server;

B. When the calling terminal needs to be switched, establish a two-way connection between the media resource server and the calling terminal with the switching destination IP address of the calling terminal, and change the first connection to the media resource server One-way connection to the calling terminal to complete the handover.

The step B directly establishes a two-way connection between the media resource server and the calling terminal by using the handover destination IP address of the calling terminal. Alternatively, establishing the two-way connection between the media resource server and the calling terminal with the switching destination IP address of the calling terminal in step B includes the step of: establishing the media resource server with the switching destination IP address of the calling terminal. A one-way connection from the resource server to the calling terminal; change the connection to a two-way connection.

After the step B, a step is further included: C, deleting the first connection.

The current location of the calling terminal is queried through the user location function device in the network attachment subsystem.

The connection of the calling terminal and the called terminal to the media resource server is completed through SIP signaling.

Another roaming handover method of the present invention comprises steps:

A. When the call connection starts, query the current location of the called terminal through the network attachment subsystem, use the current location of the called terminal to determine the media resource server closest to the called terminal, and use the IP address of the called terminal to establish the called terminal. A bidirectional first connection between the calling terminal and the media resource server, using the IP address of the calling terminal to establish a bidirectional connection between the calling terminal and the media resource server;

B. When the called terminal needs to be handed over, establish a bidirectional connection between the media resource server and the called terminal with the handover destination IP address of the called terminal, and change the first connection to the media resource server One-way connection to the called terminal to complete the handover.

In the step B, the two-way connection between the media resource server and the called terminal is directly established with the handover destination IP address of the called terminal. Alternatively, establishing the two-way connection between the media resource server and the called terminal with the IP address of the called terminal’s switching destination as described in step B includes the step of: establishing the media resource server with the switching destination IP address of the called terminal. A one-way connection from the resource server to the called terminal; change the connection to a two-way connection.

After the step B, a step is further included: C, deleting the first connection.

The current location of the called terminal is queried through the user location function device in the network attachment subsystem.

The IP-based voice network provided by the present invention includes: a proxy call session control function device or a network attachment subsystem, and at least one media resource server, wherein:

The network attachment subsystem queries the current locations of the calling terminal and the called terminal respectively at the beginning of the call connection, and determines the closest distance to the calling terminal and the called terminal based on the current locations of the calling terminal and the called terminal, respectively. media resource server for

The agent participating in the call calls the session control function device, and determines the media resource server closest to the address according to the address information of the device;

The agent calls the media resource server participating in the call determined by the SCF device or the network attachment subsystem, and is used to establish a connection with the calling terminal and the called terminal, and complete the handover.

The beneficial effects of the present invention are as follows:

The invention provides an IP-based voice network, which is used to determine the media resource server participating in the call, make the respectively determined media resource server the shortest distance from the calling terminal and the called terminal, and use the media resource server to complete switching.

Utilizing the IP-based voice network, the method of the invention determines the media resource server participating in the call according to the location of the caller or the address of the P-CSCF that accepts the call when the caller initiates a call. Since the distribution of media resource servers is relatively flexible, the number and location of which can be set according to the actual situation, so the determined media resource server and the calling terminal can keep a very short distance, and the shorter route can reduce the time delay. The user's call duration is generally not very long, so even if a roaming switch occurs during the call duration, it will not be far away from the determined media resource server. In the process of using the method of the present invention to complete the switch, The probability of call interruption is greatly reduced, and even if a call is interrupted, the duration of the interruption will be shorter than that of the prior art, thereby bringing better user experience to users.

It can be seen from the flow of the method of the present invention that the method always maintains two connections from the media resource server to the terminal at the switching side during the switching process, thus further ensuring the continuity of the call during the switching process.

The beneficial effect of the handover of the called terminal in the present invention is the same as that of the handover of the calling terminal.

Description of drawings

Fig. 1 is a schematic diagram of a media resource server of the present invention;

FIG. 2 is a schematic diagram of an IP-based voice network comprising a proxy call session control function device according to the present invention;

FIG. 3 is a schematic diagram of an IP-based voice network including a network attachment subsystem according to the present invention;

FIG. 4 is a flow chart of the steps of roaming switching of the calling terminal in the present invention;

FIG. 5 is a schematic flow diagram of the roaming handover of the calling terminal and the indirect establishment of a two-way connection according to the present invention;

FIG. 6 is a schematic flow diagram of roaming handover and direct establishment of a two-way connection by the calling terminal according to the present invention;

FIG. 7 is a flow chart of the steps of roaming handover of the called terminal in the present invention.

Detailed ways

In order to increase the probability of smooth switching when the user roams and switches during a continuous call, the present invention provides a media resource server, as shown in FIG. 1 , which includes a connection module and a switching module connected to each other.

The connection module is used to establish a media connection with the calling terminal and the called terminal;

The switching module is configured to switch between connections established by the connection module.

Referring to Fig. 2 and Fig. 3, the media resource server is applied in the VoIP network of the present invention, and its distribution in the VoIP network can be determined according to the actual situation. The VoIP network of the present invention also includes a proxy call session control function device or a network attachment subsystem.

The proxy call session control function device is used to determine the media resource server participating in the call;

The network attachment subsystem is used to determine the media resource server participating in the call;

The media resource server is used to establish connections with the calling terminal and the called terminal, and complete switching.

Applying the above-mentioned media resource server and VoIP network, the present invention provides a method for roaming switching on the calling side, as shown in Figure 4, including the following steps:

S11. When the call connection starts, determine the media resource server participating in the call;

S12. Establishing two-way connections from the calling terminal to the media resource server and from the called terminal to the media resource server by switching the original IP address;

S13. When the calling terminal needs to be handed over, obtain the IP address of the handover destination side;

S14. Establish a two-way connection between the media resource server and the calling terminal using the switching destination IP address of the calling terminal, and change the connection established by the calling terminal using the switching original IP address to the media resource server to One-way connection of the calling terminal;

S15. Delete the calling terminal to switch the connection established by the original IP address.

The method of the present invention is specifically described below through two examples.

Example 1: Complete the roaming handover on the calling side by indirectly establishing a two-way connection, including the following steps:

- At the beginning of a call connection, the media resource servers participating in the call are determined.

When the calling terminal initiates a call connection, the proxy call session control function device closest to the calling terminal in the VoIP system of the present invention will accept the call, and then search for the distance from the address according to the address information of the proxy call session control function device. The nearest media resource server obtains the media resource server closest to the calling terminal.

Or, use the network attachment subsystem in the VoIP system of the present invention to directly search for the location information of the calling terminal, and determine the media resource server closest to the calling terminal accordingly.

- Establishing bidirectional connections from the calling terminal to the media resource server and from the called terminal to the media resource server respectively by switching the original IP address.

After determining the media resource server closest to the calling terminal, as shown in FIG. side IP address), the media stream of the calling terminal is connected to the media resource server through SIP signaling, and the two-way connection (first connection) between the calling terminal and the media resource server is established, and then from the media resource server Establish a two-way connection to the called terminal to complete the call connection.

- When the calling terminal needs to be handed over, obtain the IP address of the handover destination side.

During the continuation of the call, when the calling terminal moves from network A to network B, the calling terminal will initiate a handover at the network boundary, or the network side will judge and initiate the handover. Afterwards, the calling terminal applies to the network B and obtains the handover destination IP address.

-Indirectly establishing a two-way connection between the media resource server and the calling terminal with the switching destination IP address of the calling terminal, and changing the first connection to a one-way connection between the media resource server and the calling terminal , to complete the switch.

Referring to Figure 5, on the premise of maintaining the IP address of the calling and called party in network A and the two-way voice connection established with the IP address in network A, the connection module uses the calling terminal in network B The IP address of the media resource server establishes a one-way connection (second connection) to the calling terminal.

At this time, the calling terminal sends the voice IP data packet to the called terminal through the first connection, and receives the voice IP data packet from the called terminal through the first and second connections.

Referring to FIG. 5 , the switching module in the media resource server is used to change the first connection to a one-way connection from the media resource server to the calling terminal, and to change the second connection to a two-way connection.

At this time, the calling terminal sends the voice IP data packet to the called terminal through the second connection, and receives the voice IP data packet from the called terminal through the first and second connections. That is, the two-way connection between the calling terminal and the media resource server is established with the IP address of the calling terminal in network B, and the above steps maintain the two-way connection between the media resource server and the called terminal, thus forming the calling terminal. The terminal is based on the complete IP connection of the handover destination IP address.

- Delete the calling terminal to switch the connection established by the original IP address.

Referring to FIG. 5 , after the handover is completed, the connection (first connection) from the calling terminal to the media resource server established with the IP address of the calling terminal in network A is released. Further save network resources.

At this time, there are only two-way connections between the calling terminal and the media resource server established with the IP address of the calling terminal in network B, and between the called terminal and the media resource server established with the IP address of the called terminal in network A. Two-way connection to the media resource server.

Example 2: Complete the roaming handover on the calling side by directly establishing a two-way connection, including the following steps:

- At the beginning of a call connection, the media resource servers participating in the call are determined. (same as Example 1)

- As shown in FIG. 6 , two-way connections from the calling terminal to the media resource server and from the called terminal to the media resource server are respectively established by switching the original IP address. (same as Example 1)

- When the calling terminal needs to be handed over, obtain the IP address of the handover destination side. (same as Example 1)

- directly establishing a two-way connection between the media resource server and the calling terminal with the switching destination IP address of the calling terminal, and changing the first connection to a one-way connection between the media resource server and the calling terminal , to complete the switch.

Referring to Figure 6, under the premise of maintaining the IP address of the called terminal in network A and the two-way voice connection established with the IP address of the called terminal in network A, the connection module uses the calling terminal in the network The IP address in B establishes a two-way connection (second connection) between the media resource server and the calling terminal. At the same time, the switching module in the media resource server is used to change the first connection into a one-way connection from the media resource server to the calling terminal.

At this time, the calling terminal sends the voice IP data packet to the called terminal through the second connection, and receives the voice IP data packet from the called terminal through the first and second connections. That is, the two-way connection between the calling terminal and the media resource server is established with the IP address of the calling terminal in network B, and the two-way connection between the media resource server and the called terminal is maintained, so that the calling terminal is formed based on Switch the complete IP connection of the destination IP address.

- Referring to Figure 6, delete the calling terminal to switch the connection established by the original IP address. (same as Example 1)

Applying the above-mentioned media resource server and VoIP network, the present invention provides a method for roaming switching of the called side, as shown in Figure 7, including the following main steps:

S21. When the call connection starts, determine the media resource server participating in the call;

S22. Establish bidirectional connections from the calling terminal to the media resource server and from the called terminal to the media resource server by switching the original IP address;

S23. When the called terminal needs to be handed over, obtain the IP address of the handover destination side;

S24. Establish a two-way connection between the media resource server and the called terminal using the handover destination IP address of the called terminal, and change the connection established by the called terminal using the original IP address to the media resource server to the called terminal One-way connection called terminal;

S25. Delete the connection established by the called terminal using the original IP address.

The method of the present invention is specifically described below through two examples.

Example 3: Complete the roaming handover on the called side by indirectly establishing a two-way connection, including the following steps:

- At the beginning of a call connection, the media resource servers participating in the call are determined.

When the calling terminal initiates a call connection, the network attachment subsystem in the VoIP system of the present invention is used to directly search for the location information of the called terminal, and accordingly determine the media resource server closest to the called terminal.

- Establishing bidirectional connections from the calling terminal to the media resource server and from the called terminal to the media resource server respectively by switching the original IP address.

After determining the media resource server closest to the called terminal, use the connection module set in the media resource server and cooperate with the existing connection process to establish the media resource server through SIP signaling with the IP address in the network A where the calling terminal is currently located. The two-way connection between the resource server and the calling terminal, the media resource server establishes the two-way connection between the media resource server and the called terminal with the IP address in the network A where the called terminal is currently located through SIP signaling (the first connection ) to complete the call connection.

- When the called terminal needs to be handed over, obtain the IP address of the handover destination side.

During the continuation of the call, when the called terminal moves from network A to network B, the called terminal will initiate a handover at the network boundary, or the network side will judge and initiate the handover. Afterwards, the called terminal applies to network B and obtains the handover destination IP address.

-Indirectly establish a two-way connection between the media resource server and the called terminal using the handover destination IP address of the called terminal, and change the connection established by the called terminal using the original IP address to the media resource server to the called terminal A one-way connection called a terminal.

On the premise of maintaining the IP address of the calling terminal in network A and the two-way voice connection established with the IP address in network A, the connection module establishes the two-way voice connection with the IP address of the called terminal in network B A one-way connection (second connection) from the media resource server to the called terminal.

At this time, the called terminal sends the voice IP data packet to the calling terminal through the first connection, and receives the voice IP data packet from the calling terminal through the first and second connections.

The switching module in the media resource server is used to change the first connection into a one-way connection from the media resource server to the called terminal, and change the second connection into a two-way connection.

At this time, the called terminal sends the voice IP data packet to the calling terminal through the second connection, and receives the voice IP data packet from the calling terminal through the first and second connections. That is, the two-way connection between the called terminal and the media resource server is established with the IP address of the called terminal in network B, and the above steps maintain the two-way connection between the media resource server and the calling terminal, thus forming the called The terminal is based on the complete IP connection of the handover destination IP address.

- Delete the connection established by the called terminal to switch the IP address of the original side.

After the handover is completed, release the connection (first connection) from the called terminal to the media resource server established with the IP address of the called terminal in network A. Further save network resources.

At this time, there is only the two-way connection between the called terminal and the media resource server established with the IP address of the called terminal in network B, and the connection between the calling terminal and the media resource server established with the IP address of the calling terminal in network A. Two-way connection to the media resource server.

Example 4: Complete the roaming handover on the called side by directly establishing a two-way connection, including the following steps: .

- At the beginning of a call connection, the media resource servers participating in the call are determined. (same as example three)

- Establishing bidirectional connections from the calling terminal to the media resource server and from the called terminal to the media resource server respectively by switching the original IP address. (same as example three)

- When the called terminal needs to be handed over, obtain the IP address of the handover destination side. (same as example three)

- directly establishing a two-way connection between the media resource server and the called terminal with the destination IP address of the called terminal, and changing the first connection to a one-way connection from the media resource server to the calling terminal, Complete the switch.

On the premise of maintaining the IP address of the calling terminal in network A and the two-way voice connection established with the IP address of the calling terminal in network A, the connection module establishes the IP address of the called terminal in network B A two-way connection (second connection) between the media resource server and the called terminal. At the same time, the switching module in the media resource server is used to change the first connection into a one-way connection from the media resource server to the called terminal.

At this time, the called terminal sends the voice IP data packet to the calling terminal through the second connection, and receives the voice IP data packet from the calling terminal through the first and second connections. That is, the two-way connection between the called terminal and the media resource server is established with the IP address of the called terminal in network B, and the two-way connection between the media resource server and the calling terminal is maintained, so that the called terminal is formed based on Switch the complete IP connection of the destination IP address.

- Delete the connection established by the calling terminal with the original IP address. (same as example three)

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (15)

1, a kind of method of roaming switching is characterized in that, comprises the following steps:

A, when call proceeding begins, current location by Network Attachment Subsystem inquiring calling terminal, current location with described calling terminal is determined and the nearest Media Resource Server of calling terminal, perhaps determine and the nearest Media Resource Server in this address according to the address information of the Proxy Call Session Control Function equipment P-CSCF of call accepted, and set up between calling terminal and the described Media Resource Server two-way first with calling terminal IP address and connect, set up two-way connection between terminal called and the described Media Resource Server with the IP address of terminal called;

B, when calling terminal need switch, set up two-way connection between described Media Resource Server and the calling terminal with the switching destination IP address of calling terminal, and connect described first and to change to the unidirectional connection of described Media Resource Server to calling terminal, finish switching.

2, the method for claim 1 is characterized in that, described step B directly sets up two-way connection between described Media Resource Server and the calling terminal with the switching destination IP address of calling terminal.

3, the method for claim 1 is characterized in that, sets up two-way connection between described Media Resource Server and the calling terminal with the switching destination IP address of calling terminal described in the step B, comprises step:

The unidirectional connection of described Media Resource Server to calling terminal set up in switching destination IP address with calling terminal;

This connection is changed to two-way connection.

4, as each described method of claim 1 to 3, it is characterized in that, also comprise step after the described step B:

C, connect deletion with described first.

5, method as claimed in claim 4 is characterized in that, the current location of described calling terminal is by the user location function equipment query in the Network Attachment Subsystem.

6, method as claimed in claim 4 is characterized in that, finishes calling terminal and terminal called being connected to described Media Resource Server by the SIP signaling.

7, method as claimed in claim 4 is characterized in that, when calling terminal need switch, is initiated to switch by calling terminal among the described step B, is perhaps initiated to switch by network side.

8, a kind of method of roaming switching is characterized in that, comprises the following steps:

A, when call proceeding begins, current location by Network Attachment Subsystem inquiry terminal called, current location with described terminal called is determined and the nearest Media Resource Server of terminal called, and set up between terminal called and the described Media Resource Server two-way first with terminal called IP address and connect, set up two-way connection between calling terminal and the described Media Resource Server with the IP address of calling terminal;

B, when terminal called need switch, set up two-way connection between described Media Resource Server and the terminal called with the switching destination IP address of terminal called, and connect described first and to change to the unidirectional connection of described Media Resource Server to terminal called, finish switching.

9, method as claimed in claim 8 is characterized in that, described step B directly sets up two-way connection between described Media Resource Server and the terminal called with the switching destination IP address of terminal called.

10, method as claimed in claim 8 is characterized in that, sets up two-way connection between described Media Resource Server and the terminal called with the switching destination IP address of terminal called described in the step B, comprises step:

The unidirectional connection of described Media Resource Server to terminal called set up in switching destination IP address with terminal called;

This connection is changed to two-way connection.

11, as each described method of claim 8 to 10, it is characterized in that, also comprise step after the described step B:

C, connect deletion with described first.

12, method as claimed in claim 11 is characterized in that, the current location of described terminal called is by the user location function equipment query in the Network Attachment Subsystem.

13, method as claimed in claim 12 is characterized in that, finishes terminal called and calling terminal being connected to described Media Resource Server by the SIP signaling.

14, method as claimed in claim 13 is characterized in that, when terminal called need switch, is initiated to switch by terminal called among the described step B, is perhaps initiated to switch by network side.

15, a kind of IP-based speech network comprises: Proxy Call Session Control Function equipment or Network Attachment Subsystem, it is characterized in that described network also comprises at least one Media Resource Server, wherein:

Described Network Attachment Subsystem is when call proceeding begins, the current location of inquiring calling terminal and terminal called is determined and calling terminal and the nearest Media Resource Server of terminal called respectively with the current location of described calling terminal and terminal called respectively;

Participate in the Proxy Call Session Control Function equipment of calling, determine and the nearest Media Resource Server in this address according to the address information of this equipment;

The Media Resource Server that the participation that described Proxy Call Session Control Function equipment or Network Attachment Subsystem are determined is called out is used to set up and being connected of calling terminal and terminal called, and finishes switching.

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