CN103139156B - A kind of Media Stream Bypass implementation method and equipment - Google Patents

Abstract

The present invention discloses a method and device for realizing media stream bypass. The SBC processes the session initiation request message sent by the calling terminal and the session initiation response message sent by the called terminal, so that the called terminal can receive the session from the received session. The address and port number of the calling terminal are obtained from the initiation request message, and the calling terminal can obtain the address and port number of the called terminal from the received session initiation response message. Therefore, the calling terminal and the called terminal can perform media direct transmission according to the acquired address and port number of the opposite end, realizing media stream bypass.

Description

Method and device for implementing media stream bypass

technical field

The present invention relates to the technical field of communications, in particular to a method and device for realizing media stream bypass.

Background technique

IMS (IP Multimedia Subsystem, IP Multimedia Subsystem) is an open system architecture based on the SIP (Session Initiation Protocol, Session Initiation Protocol) protocol. , More diversified multimedia business needs. SBC (Session Border Controller, Session Border Controller) is located at the edge of the IMS network, used for IP (Internet Protocol, Internet Protocol) access, household communication and security protection, and exists between the access network and IMS network and different IMS networks. It is the access point for users to access the IMS.

For overseas VoIP (Voice over Internet Protocol, telephone over Internet Protocol) services, voice calls may be transferred through the SBC. Normally, the SBC will replace the address in line c in the SDP (Session Description Protocol, Session Description Protocol) information in the passed SIP message with its own address, and replace the port in line m with its own port. As shown in FIG. 1 , it is a schematic flow diagram of a session implementation in the prior art. Among them, user A and user B are both overseas users. When user A initiates a call to user B, the request and response are transferred by SBC 1 and SBC 2 deployed overseas, and transmitted as shown in the figure. In this solution, both signaling and media streams are transferred through the SBC, and media direct transmission cannot be realized.

Contents of the invention

Embodiments of the present invention provide a method and device for realizing media stream bypass, so as to realize direct media transmission between a calling terminal and a called terminal.

In order to achieve the above purpose, the embodiment of the present invention provides a method for implementing media stream bypass, including:

When the session border controller SBC receives the session initiation request message sent by the calling terminal, it saves the address and port number of the calling terminal in the first information field in the message to the extended second information field, and uses its own SBC address replace the calling terminal address and the port number in the first information field with the port number respectively, and send the revised message to the Internet Multimedia Subsystem IMS core network for processing;

When the SBC receives the session initiation request message processed by the IMS core network, use the address and port number of the calling terminal in the second information field in the message to replace the SBC address and port number in the first information field respectively, delete the second information field, and send the modified message to the called terminal;

When the SBC receives the session initiation response message returned by the called terminal, it saves the called terminal address and port number in the first information field in the message to the expanded second information field, and uses its own SBC address and port number respectively Replace the called terminal address and port number in the first information field, and send the modified message to the IMS core network for processing;

When the SBC receives the session initiation response message processed by the IMS core network, use the address and port number of the called terminal in the second information field in the message to replace the SBC address and port number in the first information field respectively, delete The second information field, and send the modified message to the calling terminal, so that the calling terminal and the called terminal can perform media direct transmission according to the acquired address and port number of the opposite end.

The embodiment of the present invention also provides an SBC, including:

The first receiving module is configured to receive the session initiation request message sent by the calling terminal and the session initiation response message sent by the called terminal;

The first processing module is configured to, when the first receiving module receives the session initiation request message sent by the calling terminal, save the address and port number of the calling terminal in the first information field in the message to the extended second information field, replace the calling terminal address and port number in the first information field with its own SBC address and port number, and send the modified message to the Internet Multimedia Subsystem IMS core network for processing; when the first When the receiving module receives the session initiation response message sent by the called terminal, it saves the called terminal address and port number in the first information field in the message to the expanded second information field, and uses its own SBC address and port number respectively Replace the called terminal address and port number in the first information field, and send the modified message to the IMS core network for processing;

The second receiving module is configured to receive the session initiation request/response message processed by the IMS core network;

The second processing module is configured to, when the second receiving module receives the session initiation request message processed by the IMS core network, use the address and port number of the calling terminal in the second information field in the message to replace the first SBC address and port number in an information field, delete the second information field, and send the modified message to the called terminal; when the second receiving module receives the session initiation response message processed by the IMS core network , use the address and port number of the called terminal in the second information field in the message to replace the SBC address and port number in the first information field respectively, delete the second information field, and send the modified message to the master The calling terminal, so that the calling terminal and the called terminal can perform media direct transmission according to the acquired address and port number of the opposite end.

Compared with the prior art, the present invention has at least the following advantages:

In the embodiment of the present invention, the SBC processes the session initiation request message sent by the calling terminal and the session initiation response message sent by the called terminal, so that the called terminal can obtain the The calling terminal can obtain the address and port number of the called terminal from the received session initiation response message. Therefore, the calling terminal and the called terminal can perform media direct transmission according to the acquired address and port number of the opposite end.

Description of drawings

FIG. 1 is a schematic flow diagram of a session implementation in the prior art;

FIG. 2 is a schematic flowchart of a method for implementing media stream bypass provided by an embodiment of the present invention;

FIG. 3 is a schematic flowchart of a method for implementing media stream bypass in application scenario 1 provided by an embodiment of the present invention;

Fig. 4 is a schematic flow diagram of a method for implementing media stream bypass under the second application scenario provided by the embodiment of the present invention;

5 and 6 are schematic structural diagrams of the SBC provided by the embodiment of the present invention.

detailed description

In order to realize media flow bypass, in the technical solution provided by the embodiment of the present invention, the SBC processes the session initiation request message sent by the calling terminal and the session initiation response message sent by the called terminal, so that the called terminal can receive The address and port number of the calling terminal can be obtained from the received session initiation request message, and the calling terminal can obtain the address and port number of the called terminal from the received session initiation response message. Therefore, the calling terminal and the called terminal can perform media direct transmission according to the acquired address and port number of the opposite end.

The technical solutions provided by the embodiments of the present invention will be described below in conjunction with the accompanying drawings.

As shown in FIG. 2, it is a schematic flowchart of a method for implementing media stream bypass provided by an embodiment of the present invention, which may include the following steps:

Step 201, when the SBC receives the session initiation request message sent by the calling terminal, it saves the address and port number of the calling terminal in the first information field in the message to the expanded second information field, and uses its own SBC address and The port number replaces the address of the calling terminal and the port number in the first information field respectively, and sends the modified message to the IMS core network for processing.

Specifically, the session initiation request message sent by the calling terminal will carry the address and port number of the calling terminal. In the prior art, after receiving the session initiation request message sent by the calling terminal, the SBC replaces the address and port number of the calling terminal carried in the message with its own SBC address, and the message reaches the called terminal after being processed by the core network , the called terminal cannot obtain the address and port number of the calling terminal from the message. However, in the embodiment of the present invention, after receiving the session initiation request sent by the calling terminal, the SBC will save the address and port number of the calling terminal carried in the first information field in the message to the extended second information field.

Wherein, in the embodiment of the present invention, the address and port number in the first information field are specifically the address in line c and the port number in line m of the SDP information in the session initiation request/response message; the extended second information The domain is specifically the extension line in the SDP information in the session initiation request/response message.

Step 202. When the SBC receives the session initiation request message processed by the IMS core network, it performs media release on the session initiation request message, and sends the modified message to the called terminal.

Specifically, the SBC performs media release on the session initiation request message as follows: use the address and port number of the calling terminal in the second information field in the message to replace the SBC address and port number in the first information field respectively, delete The second information field. After receiving the session initiation request message modified by the SBC, the called terminal can obtain the address and port number of the calling terminal from the message.

Wherein, in the technical solutions provided by the embodiments of the present invention, an SBC address list may be configured in the SBC to store SBC address information. After the SBC receives the session initiation request message processed by the IMS core network, it can determine whether the SBC address in the second information field in the message is recorded in the SBC address list stored by itself. If it is judged to be yes, perform media release on the message; otherwise, do not perform media release on the message, but directly replace the SBC address and port number in the first information field in the message with its own SBC address and port number.

Step 203, when the SBC receives the session initiation response message returned by the called terminal, save the called terminal address and port number in the first information field in the message to the expanded second information field, use its own SBC address and The port number respectively replaces the called terminal address and port number in the first information field, and sends the modified message to the IMS core network for processing.

Step 204: When the SBC receives the session initiation response message processed by the IMS core network, it performs media release on the session initiation response message, and sends the modified message to the calling terminal.

Specifically, the processing flow of steps 203-204 is similar to steps 201-202, and will not be repeated here. Wherein, after receiving the session initiation response message modified by the SBC, the calling terminal can obtain the address and port number of the called terminal from the message.

Step 205, the calling terminal and the called terminal perform direct media transmission according to the acquired address and port number of the opposite end.

It should be noted that, in the technical solution provided by the embodiment of the present invention, before the session ends, the SBC can save the content of the session initiation request message in the session. After the SBC receives the session initiation response message returned by the called terminal, According to the content of the session initiation request message stored by itself, it can be judged whether its own address is the same as the address in the first information field in the session initiation request message corresponding to the message processed by the IMS core network. If they are the same, it shows that the SBC has released the media for the session initiation request message, and the SBC saves the called terminal address and port number in the first information field in the session initiation response message to the expanded second information field, and uses its own The SBC address and port number replace the called terminal address and port number in the first information field respectively; if they are different, it indicates that the SBC has not released the media for the session initiation request message, and the SBC uses its own SBC address and port number to replace The address and port number of the called terminal in the first information field in the session initiation response message.

It should be recognized that in the technical solutions provided by the embodiments of the present invention, the calling terminal and the called terminal in a session interaction process can access the IMS core network through the same SBC, or can access the IMS core network through two SBCs . For example, when the calling terminal and the called terminal access the IMS core network through two SBCs, the SBC that receives the session initiation request message sent by the calling terminal is the calling side SBC, and the IMS core network After the initiation request message is processed, it is sent to the SBC on the called side, and the SBC on the called side sends the modified session initiation request message to the called terminal; the SBC that receives the session initiation response message returned by the called terminal is the SBC on the called side, and the IMS The core network processes the session initiation response message sent by the called side SBC and sends it to the calling side SBC, and the calling side SBC sends the modified session initiation response message to the calling terminal.

The technical solutions provided by the embodiments of the present invention will be described in more detail below in conjunction with specific application scenarios.

Application Scenario 1

In this embodiment, the calling terminal (user A) and the called terminal (user B) access the IMS core network through the same SBC, and the SBC is configured with an address list of the SBC in the same area as itself.

Wherein, the SBC can be divided into regions according to the policy configured by the operator or the IP address of the SBC. For example, SBCs can be divided into domestic SBCs and overseas SBCs. Taking an overseas application scenario as an example, in the embodiment of the present invention, an overseas SBC address list may be configured in the overseas SBC to store address information of the overseas SBC.

As shown in FIG. 3 , it is a schematic flowchart of a method for implementing media stream bypass in the application scenario 1 provided by the embodiment of the present invention, which may include the following steps:

In step 301, the SBC receives a session initiation request message (INVITE message) sent by user A.

Wherein, line c of the INVITE message (line c of the SDP information in the INVITE message) carries the address (IP_A) of user A, and line m carries the port number (PORT_A) of user A. In the embodiment of the present invention, the port number carried in line m in the SDP message is not reflected in the flow chart.

Step 302, SBC adds an extended a row in the received INVITE message (increases the extended a row in the SDP information in the INVITE message), is used to preserve IP_A and PORT_A, and uses its own SBC address (IP_SBC) and port The number (PORT_SBC) replaces the IP_A carried in line c and the PORT_A carried in line m of the INVITE message.

Specifically, after receiving the INVITE message sent by user A, the SBC determines whether the address information (IP_A) carried in line c of the INVITE message is recorded in the SBC address list according to the SBC address list stored by itself. Wherein, since the address information of the SBC is stored in the SBC address list stored in the SBC, and the address information carried in line c of the INVITE message received by the SBC is the address (IP_A) of user A, that is, the address information of the INVITE message in line c of the INVITE message. The address information carried in the line is not recorded in the SBC address list. Therefore, the SBC adds an extended line a to the received INVITE message to save IP_A and PORT_A, and replaces the IP_A and line carried in line c of the INVITE message with its own SBC address and port number (IP_SBC and PORT_SBC) respectively. PORT_A carried in line m.

Step 303, the SBC sends the INVITE message to the IMS-Core (IMS core network), and receives the INVITE message processed by the IMS-Core.

Wherein, because in this embodiment, both user A and user B access the IMS core network through the same SBC, therefore, the INVITE message processed by the IMS core network is forwarded to user B through the SBC that connects the INVITE message to the IMS core network .

Step 304 , the SBC uses the IP_A and PORT_A carried in the extended line a of the received INVITE message to replace the IP_SBC carried in line c and the PORT_SBC carried in line m respectively, and deletes the extended line a.

Specifically, after receiving the INVITE message processed by the IMS core network, the SBC determines whether the address information (IP_SBC) carried in line c of the INVITE message is recorded in the SBC address list according to the SBC address list stored by itself. Wherein, since what is stored in the SBC address list stored in the SBC is the address information of the SBC, and the address information carried in the c line of the INVITE message received by the SBC is the address of the SBC (IP_SBC), that is, the c line of the INVITE message The address information carried in is recorded in the SBC address list. Therefore, the SBC uses the IP_A and PORT_A carried in the extended line a of the received INVITE message to replace the IP_SBC carried in line c and the PORT_SBC carried in line m respectively, and deletes the extended line a.

Step 305, SBC sends the INVITE message to user B.

Wherein, after receiving the INVITE message, user B obtains the address (IP_A) of user A carried in line c of the INVITE message and the port number (PORT_A) of user A carried in line m of the INVITE message.

Step 306, the SBC receives the response message (200ok message) returned by user B.

Wherein, line c of the 200ok message (line c of the SDP information in the 200ok message) carries the address (IP_B) of user B, and line m carries the port number (PORT_B) of user B.

Step 307, SBC adds an extended a row in the received 200ok message (increasing the extended a row in the SDP information in the 200ok message), for saving the IP_B carried in the c row of the 200ok message and in the m row PORT_B carried, and replace IP_B carried in line c and PORT_SBC carried in line m of the SDP information with IP_SBC and PORT_SBC respectively.

Specifically, after receiving the 200ok message returned by user B, the SBC determines whether the address information (IP_B) carried in line c of the 200ok message is recorded in the SBC address list according to the SBC address list stored by itself. Obviously, IP_B is not recorded in the SBC address list, and the SBC adds an extended line a to the received 200ok message to save IP_B and PORT_B, and replaces IP_B and PORT_B carried in line c of the 200ok message with IP_SBC and PORT_SBC respectively. PORT_B carried by line m.

Step 308, the SBC sends the 200ok message to the IMS-Core, and receives the INVITE message processed by the IMS-Core.

Step 309 , the SBC uses the IP_B and PORT_B carried in the extended line a of the received 200ok message to replace the IP_SBC carried in line c and the PORT_SBC carried in line m respectively, and deletes the extended line a.

Specifically, after receiving the 200ok message processed by the IMS core network, the SBC judges whether the address information (IP_SBC) carried in line c of the 200ok message is recorded in the SBC address list according to the SBC address list stored by itself. Obviously, IP_SBC is recorded in the SBC address list, and the SBC uses the IP_B and PORT_B carried in the extended line a of the received 200ok message to replace the IP_SBC carried in line c and the PORT_SBC carried in line m, respectively, and delete the extended line a .

Step 310, the SBC sends the 200ok message to user A.

Wherein, after receiving the 200ok message, user B obtains the address (IP_B) of user B carried in line c of the 200ok message and the port number (PORT_B) of user B carried in line m of the 200ok message.

Step 311, user A and user B perform media direct transmission according to the acquired address and port number of the peer device.

Application Scenario 2

In this embodiment, user A accesses the IMS core network through SBC 1, and user B accesses the IMS core network through SBC 2. SBC1 and SBC2 are in the same area, and the SBC is configured with an address list of SBCs in the same area as itself.

As shown in FIG. 4 , it is a schematic flowchart of a method for establishing a session in application scenario 2 provided by the embodiment of the present invention, which may include the following steps:

Step 401, SBC 1 receives (INVITE message) sent by user A.

Step 402, SBC 1 adds an extended line a to the received INVITE message to save IP_A and PORT_A, and replaces the line c carried in line c of the INVITE message with its own SBC address (IP_SBC 1) and port number (PORT_SBC1). The IP_A and PORT_A carried in the m line.

Step 403, SBC 1 sends the INVITE message to IMS-Core, and the IMS-Core processes the INVITE message, and sends the processed INVITE message to SBC 2.

Wherein, since user A accesses the IMS core network through SBC 1 , user B accesses the IMS core network through SBC 2 . Therefore, the INVITE message forwarded to the IMS core network through SBC 1 is processed and then forwarded to user B through SBC 2 .

Step 404, SBC 2 replaces IP_SBC 1 carried in line c and PORT_SBC 1 carried in line m with IP_A and PORT_A carried in extended line a of the received INVITE message, and deletes the extended line a.

Step 405, SBC 2 sends the INVITE message to user B.

Step 406, SBC 2 receives the 200 ok message returned by user B.

Step 407, SBC 2 adds an extended line a to the received 200ok message for saving the IP_B carried in line c and the PORT_B carried in line m of the 200ok message, and replaces the SDP information with IP_SBC2 and PORT_SBC 2 respectively The IP_B carried in line c and the PORT_B carried in line m.

Step 408 , SBC 2 sends the 200ok message to IMS-Core, and the IMS-Core processes the 200ok message, and sends the processed INVITE message to SBC 1 .

Step 409 , SBC 1 replaces IP_SBC 2 carried in line c and PORT_SBC 2 carried in line m with IP_B and PORT_B carried in extended line a of the received 200ok message, and deletes the extended line a.

Step 410, SBC 2 sends the 200ok message to user A.

Step 411, user A and user B perform media direct transmission according to the acquired address and port number of the peer device.

It can be concluded from the above description that in the technical solution provided by the embodiment of the present invention, by configuring the SBC address list in the SBC, when the session initiation request sent by the calling terminal is transferred through the SBC, and the processing of the IMS core network After arriving at the called terminal, the c line of the SDP information in the session initiation request carries the address of the calling terminal, and the m line carries the port number of the calling terminal, and the called terminal can obtain the received session initiation request. The address and port number of the calling terminal; correspondingly, after the response message of the called terminal in response to the received session initiation request is transferred by the SBC and processed by the IMS core network and reaches the calling terminal, the SDP information in the response message The address of the called terminal is carried in the c line of , and the port number of the called terminal is carried in the m line, and the calling terminal can obtain the address and port number of the called terminal in the received response message. According to the obtained peer address and port number, the calling terminal and the called terminal can perform media direct transmission to realize media stream bypass. Wherein, the calling terminal and the called terminal may access the IMS core network through the same SBC, or may respectively access the IMS core network through different SBCs.

It should be recognized that in the technical solution provided by the embodiment of the present invention, the extended line used to store the address carried in line c and the port number carried in line m is not limited to the extended line a. Under the same inventive concept, The technical solution of implementing direct media transmission between the calling terminal and the called terminal by extending other lines should also be within the scope of protection of the embodiments of the present invention.

Based on the same inventive concept as the above method, an SBC is also provided in an embodiment of the present invention.

As shown in Figure 5, a schematic structural diagram of an SBC provided by an embodiment of the present invention may include:

The first receiving module 51 is configured to receive the session initiation request message sent by the calling terminal and the session initiation response message sent by the called terminal;

The first processing module 52 is configured to, when the first receiving module 51 receives the session initiation request message sent by the calling terminal, save the address and port number of the calling terminal in the first information field in the message to the extended In the second information domain, replace the calling terminal address and port number in the first information domain with the SBC address and port number of itself, and send the modified message to the Internet Multimedia Subsystem IMS core network for processing; when said When the first receiving module 51 receives the session initiation response message sent by the called terminal, it saves the called terminal address and port number in the first information field in the message to the expanded second information field, and uses its own SBC address and The port number replaces the called terminal address and port number in the first information field respectively, and sends the modified message to the IMS core network for processing;

The second receiving module 53 is configured to receive the session initiation request/response message processed by the IMS core network;

The second processing module 54 is configured to use the address and port number of the calling terminal in the second information field in the message when the second receiving module 53 receives the session initiation request message processed by the IMS core network, respectively Replace the SBC address and port number in the first information field, delete the second information field, and send the modified message to the called terminal; when the second receiving module 53 receives the session initiated by the IMS core network When responding to a message, use the address and port number of the calling terminal in the second information field in the message to replace the SBC address and port number in the first information field respectively, delete the second information field, and replace the modified message Send it to the called terminal, so that the calling terminal and the called terminal can perform media direct transmission according to the acquired address and port number of the opposite end.

As shown in Figure 6, the SBC can also include:

Storage module 55, is used for storing SBC address list;

Correspondingly, the second processing module may be specifically configured to, after the second receiving module 53 receives the session initiation request message processed by the IMS core network, determine whether the SBC address in the first information field in the message Recorded in the SBC address list stored in the storage module 55, then use the address and port number of the calling terminal in the second information field in the message to replace the SBC address and port number in the first information field respectively, and delete the The second information field; after the second receiving module 53 receives the session initiation response message processed by the IMS core network, if it is judged that the SBC address in the first information field in the message is recorded in the storage module 55 In the SBC address list, use the address and port number of the calling terminal in the second information field in the message to replace the SBC address and port number in the first information field respectively, and delete the second information field.

Wherein, the storage module 55 is also configured to store the content of the session initiation request message;

The first processing module 52 is specifically configured to, after the first receiving module 51 receives the session response message returned by the called terminal, determine its own address according to the content of the session initiation request message stored in the storage module 55 Same as the address in the first information field in the session initiation request message corresponding to the message processed by the IMS core network, then save the called terminal address and port number in the first information field in the session initiation response message to the extended In the second information field, the address and port number of the called terminal in the first information field are respectively replaced with the SBC address and port number of itself.

Wherein, the second processing module 54 is further configured to, when the SBC address in the first information field in the session initiation request message processed by the IMS core network received by the second receiving module 53 does not record the storage module 55 stored in the SBC address list, use its own SBC address and port number to replace the SBC address and port number in the first information field in the message, and delete the second information field in the session initiation request message; When the SBC address in the first information field in the session initiation response message processed by the IMS core network received by the second receiving module 53 is not recorded in the SBC address list stored by itself, use its own SBC address and port number Respectively replace the SBC address and port number in the first information field in the session initiation response message, and delete the second information field in the session initiation response message.

Wherein, the first processing module 52 is further configured to, after the first receiving module 51 receives the session initiation response message returned by the called terminal, if according to the content of the session initiation request stored in the storage module 55, determine If its own address is different from the address in the first information field in the session initiation request message corresponding to the message processed by the IMS core network, use its own SBC address and port number to replace the first information field in the session initiation response message respectively. The address and port number of the called terminal.

Wherein, the address and port number in the first information field are specifically the address in line c and the port number in line m of the SDP information in the session initiation request/response message; the extended second information field Specifically, it is the extension line in the SDP information in the session initiation request/response message.

Preferably, the extended line is an extended line a.

It should be recognized that in the technical solution provided by the embodiment of the present invention, the extended line used to store the address carried in line c and the port number carried in line m is not limited to the extended line a. Under the same inventive concept, The technical solution of implementing direct media transmission between the calling terminal and the called terminal by extending other lines should also be within the scope of protection of the embodiments of the present invention.

Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus a necessary general-purpose hardware platform, and of course also by hardware, but in many cases the former is a better embodiment . Based on this understanding, the essence of the technical solution of the present invention or the part that contributes to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions to make a A computer device (which may be a personal computer, a server, or a network device, etc.) executes 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.

Those skilled in the art can understand that the modules in the device in the embodiment can be distributed in the device in the embodiment according to the description in the embodiment, and can also be changed and located in one or more devices different from the embodiment. The modules in the above embodiments can be combined into one module, and can also be further divided into multiple sub-modules.

The serial numbers of the above embodiments of the present invention are for description only, and do not represent the advantages and disadvantages of the embodiments.

The above disclosures are only a few specific embodiments of the present invention, however, the present invention is not limited thereto, and any changes conceivable by those skilled in the art shall fall within the protection scope of the present invention.

Claims (15)

1. A media stream bypass implementation method, characterized in that, comprising: When the session border controller SBC receives the session initiation request message sent by the calling terminal, it saves the address and port number of the calling terminal in the first information field in the message to the extended second information field, and uses its own SBC address replace the calling terminal address and the port number in the first information field with the port number respectively, and send the revised message to the Internet Multimedia Subsystem IMS core network for processing; When the SBC receives the session initiation request message processed by the IMS core network, use the address and port number of the calling terminal in the second information field in the message to replace the SBC address and port number in the first information field respectively, delete the second information field, and send the modified message to the called terminal; When the SBC receives the session initiation response message returned by the called terminal, it saves the called terminal address and port number in the first information field in the message to the expanded second information field, and uses its own SBC address and port number respectively Replace the called terminal address and port number in the first information field, and send the modified message to the IMS core network for processing; When the SBC receives the session initiation response message processed by the IMS core network, use the address and port number of the called terminal in the second information field in the message to replace the SBC address and port number in the first information field respectively, delete The second information field, and send the modified message to the calling terminal, so that the calling terminal and the called terminal can perform media direct transmission according to the acquired address and port number of the opposite end. 2. The method according to claim 1, wherein an SBC address list is configured in the SBC; After the SBC receives the session initiation request message processed by the IMS core network, if it determines that the SBC address in the first information field in the message is recorded in the SBC address list stored by itself, then use the second information in the message The address and port number of the calling terminal in the domain replace the SBC address and port number in the first information domain respectively, and delete the second information domain; After the SBC receives the session initiation response message processed by the IMS core network, if it judges that the SBC address in the first information field in the message is recorded in the SBC address list stored by itself, then use the second information in the message The address and port number of the called terminal in the field replace the SBC address and port number in the first information field respectively, and delete the second information field. 3. The method according to claim 2, wherein the SBC stores the content of the session initiation request message; After the SBC receives the session initiation response message returned by the called terminal, if it determines its own address and the first information in the session initiation request message corresponding to the message processed by the IMS core network according to the content of the session initiation request message stored by itself If the addresses in the fields are the same, then the called terminal address and port number in the first information field in the session initiation response message are saved to the expanded second information field, and the first information field is replaced with its own SBC address and port number respectively The called terminal address and port number in . 4. The method of claim 2, further comprising: When the SBC address in the first information field in the session initiation request message processed by the IMS core network received by the SBC is not recorded in the SBC address list stored by itself, the SBC uses its own SBC address and port number to replace the SBC address and port number respectively. The SBC address and port number in the first information field in the message, and delete the second information field in the session initiation request message; When the SBC address in the first information field in the session initiation response message processed by the IMS core network received by the SBC is not recorded in the SBC address list stored by the SBC, the SBC uses its own SBC address and port number to replace The SBC address and port number in the first information field in the session initiation response message, and delete the second information field in the session initiation response message. 5. The method of claim 3, further comprising: After the SBC receives the session initiation response message returned by the called terminal, if it determines its own address and the first information in the session initiation request message corresponding to the message processed by the IMS core network according to the content of the session initiation request message stored by itself If the addresses in the fields are different, the address and port number of the called terminal in the first information field in the session initiation response message are respectively replaced with their own SBC address and port number. 6. The method according to any one of claims 1-5, wherein the SBC receiving the session initiation request message sent by the calling terminal is the calling side SBC, and the IMS core network initiates the session to the calling side SBC. After the request message is processed, it is sent to the SBC on the called side, and the SBC on the called side sends the modified session initiation request message to the called terminal; The SBC that receives the session initiation response message returned by the called terminal is the called side SBC. The IMS core network processes the session initiation response message sent by the called side SBC and sends it to the calling side SBC. The calling side SBC sends the modified The session initiation response message is sent to the calling terminal. 7. The method according to any one of claims 1-5, characterized in that, the address and port number in the first information field are specifically in line c of the SDP information in the session initiation request/response message address and the port number in line m; the extended second information field is specifically the extended line in the SDP information in the session initiation request/response message. 8. The method of claim 7, wherein the extended line a is extended. 9. A session border controller SBC, characterized in that, comprising: The first receiving module is configured to receive the session initiation request message sent by the calling terminal and the session initiation response message sent by the called terminal; The first processing module is configured to, when the first receiving module receives the session initiation request message sent by the calling terminal, save the address and port number of the calling terminal in the first information field in the message to the extended second information field, replace the calling terminal address and port number in the first information field with its own SBC address and port number, and send the modified message to the Internet Multimedia Subsystem IMS core network for processing; when the first When the receiving module receives the session initiation response message sent by the called terminal, it saves the called terminal address and port number in the first information field in the message to the expanded second information field, and uses its own SBC address and port number respectively Replace the called terminal address and port number in the first information field, and send the modified message to the IMS core network for processing; The second receiving module is configured to receive the session initiation request/response message processed by the IMS core network; The second processing module is configured to, when the second receiving module receives the session initiation request message processed by the IMS core network, use the address and port number of the calling terminal in the second information field in the message to replace the first SBC address and port number in an information field, delete the second information field, and send the modified message to the called terminal; when the second receiving module receives the session initiation response message processed by the IMS core network , use the address and port number of the called terminal in the second information field in the message to replace the SBC address and port number in the first information field respectively, delete the second information field, and send the modified message to the master The calling terminal, so that the calling terminal and the called terminal perform media direct transmission according to the acquired address and port number of the opposite end. 10. The SBC of claim 9, further comprising: A storage module, configured to store the SBC address list; The second processing module is specifically configured to, when the second receiving module receives the session initiation request message processed by the IMS core network, if it is determined that the SBC address in the first information field in the message is recorded in the storage In the SBC address list stored by the module, then use the address and port number of the calling terminal in the second information field in the message to replace the SBC address and port number in the first information field respectively, and delete the second information field; After the second receiving module receives the session initiation response message processed by the IMS core network, if it judges that the SBC address in the first information field in the message is recorded in the SBC address list stored in the storage module, use the The address and port number of the called terminal in the second information field in the message replace the SBC address and port number in the first information field respectively, and delete the second information field. 11. The SBC of claim 10, wherein, The storage module is also used to store the content of the session initiation request message; The first processing module is specifically configured to, after the first receiving module receives the session response message returned by the called terminal, determine its own address and the IMS core address according to the content of the session initiation request message stored in the storage module. If the address in the first information field in the session initiation request message corresponding to the message processed by the network is the same, then the called terminal address and port number in the first information field in the session initiation response message are stored in the extended second information field, replacing the called terminal address and port number in the first information field with its own SBC address and port number respectively. 12. The SBC of claim 10, wherein, The second processing module is further configured to, when the SBC address in the first information field in the session initiation request message processed by the IMS core network received by the second receiving module does not record the SBC address stored in the storage module When in the list, use its own SBC address and port number to replace the SBC address and port number in the first information field in the message respectively, and delete the second information field in the session initiation request message; when the second receiving When the SBC address in the first information field in the session initiation response message processed by the IMS core network received by the module is not recorded in the SBC address list stored by itself, use its own SBC address and port number to replace the session initiation response respectively The SBC address and port number in the first information field in the message, and delete the second information field in the session initiation response message. 13. The SBC of claim 11 wherein, The first processing module is further configured to, after the first receiving module receives the session initiation response message returned by the called terminal, determine its own address and the IMS core address according to the content of the session initiation request stored in the storage module If the address in the first information field in the session initiation request message corresponding to the message processed by the network is different, use its own SBC address and port number to replace the address of the called terminal in the first information field in the session initiation response message respectively. address and port number. 14. The SBC according to any one of claims 9-13, characterized in that, the address and port number in the first information field are specifically in line c of the SDP information in the session initiation request/response message address and the port number in line m; the extended second information field is specifically the extended line in the SDP information in the session initiation request/response message. 15. The SBC of claim 14, wherein the extended row is an extended a-line.