WO2012034309A1

WO2012034309A1 - Method, terminal and system for file transfers between session initiation protocol (sip) terminals in network address translation (nat) network

Info

Publication number: WO2012034309A1
Application number: PCT/CN2010/078797
Authority: WO
Inventors: 陈红领
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-09-19
Filing date: 2010-11-16
Publication date: 2012-03-22
Also published as: CN101964785A

Abstract

Disclosed are a method, terminal and system for file transfers between Session Initiation Protocol (SIP) terminals in a Network Address Translation (NAT) network, wherein the method includes: a source terminal establishes a Transmission Control Protocol (TCP) direct connection channel with a destination terminal through a server (101); and the source terminal performs file transfers with the destination terminal through the TCP direct connection channel (102). With the present invention, the file transfer channel is dynamically selected based on the topology architecture of the network where the SIP terminals locate, and when two SIP terminals locate in different private networks behind NAT network devices, the bidirectional file transfers between two SIP terminals can be realized through the TCP direct connection channel with no need of a Message Session Relay Protocol (MSRP) channel with the transfer of a server, thus effectively utilizing the network topology architecture, increasing the file transfer rate, reducing the bandwidth occupancy, and furthermore reducing server loads. When the above TCP direct connection channel is established unsuccessfully, file transfers can be performed by switching to the MSRP channel with the transfer of the server, thus enabling the file transfer manner with selectivity and flexibility.

Description

Method, terminal and system for file transmission between SIP terminals in NAT network

The present invention relates to the field of communications, and in particular, to a method, a terminal, and a system for transferring files between SIP terminals in an IMS service NAT network. Background technique

In the IP Multimedia Subsystem (IMS) business, file transfer is one of the must-have features available to users. The file transfer function provides a way to transfer files between different users in real time, which is a good way to share documents, pictures and multimedia files.

With the rapid development of the Internet and the limitation of the number of addresses of the fourth edition (IPv4, Internet Protocol v4) of the Internet Protocol, Network Address Translation (NAT) devices are widely used. A NAT network device allows multiple hosts on the same NAT network device to share a public network (usually the network behind the same NAT network device is called the private network and the network in front of the NAT network device is called the public network). A private IP address communicates with other hosts on the public network through a NAT network device. However, direct interworking between hosts in the private network behind different NAT network devices is not possible.

At present, the file transfer mechanism of the SIP terminal is based on the Session Initiation Protocol (SIP), the Message Session Relay Protocol (MSRP), and the Session Discription Protocol (SDP). That is, each SIP terminal performs session negotiation through an invite (session message), and media information negotiation through SDP. If the session negotiation is successful, between the file sender (source terminal) and the server, the server and the file receiver ( The destination channel is respectively established with a transmission channel; after that, the file is first transmitted from the sender to the server by using the MSRP protocol, and then transferred from the server. To the recipient. It can be seen from the file transmission method of the existing SIP terminal that the file transfer between the SIP terminals must be transited by the intermediate server, and in the case of the current network bandwidth becoming increasingly tight, especially when transferring large files, this file transmission method There are drawbacks of occupying a large amount of network bandwidth for a long time, and the transmission speed is greatly affected by server performance and network bandwidth. Summary of the invention

The main purpose of the present invention is to provide a method, a terminal and a system for file transmission between SIP terminals in a NAT network, which can improve file transmission efficiency between SIP terminals and save network resources.

The invention provides a method for transferring files between SIP terminals in a NAT network, comprising: the source terminal establishes a TCP direct communication channel with a transmission control protocol between the destination terminal and the destination terminal;

The source terminal performs file transmission with the destination terminal through the established TCP direct connection channel.

The source terminal establishes a TCP direct connection channel with the destination terminal by using the server: the source terminal sends a NAT address and a port, and a file transmission request carrying the file identifier to the destination terminal through the server;

Receiving, by the source terminal, a NAT address and a port of the destination terminal sent by the destination terminal by using the server, and a response message of the consent receiving file fed back by the destination terminal;

A TCP direct communication channel is established by using a NAT address and a port of each of the source terminal and the destination terminal.

After the source terminal establishes a TCP direct connection channel with the destination terminal through the server, the source terminal further includes:

If the TCP direct connection channel fails to be established, the source terminal establishes a source MSRP channel with the server;

The source terminal performs file transmission with the destination terminal through the source MSRP channel and the destination MSRP channel between the destination terminal and the server.

The specific configuration of the source MSRP channel between the source terminal and the server includes: Sending, by the server, a session request message to the destination terminal by using a server;

After the destination MSRP channel between the destination terminal and the server is successfully established, the source terminal receives the response message from the destination terminal that is fed back by the server;

The remote terminal establishes a source MSRP channel with the server according to the response message.

The present invention also provides a terminal for transferring files between SIP terminals in a NAT network, including a direct connection channel establishment module and a first file transmission module, where:

a direct channel establishing module, configured to establish a TCP direct connection channel with the destination terminal through the server;

The first file transmission module is configured to perform file transmission with the destination terminal through the established TCP direct connection channel.

The direct channel establishing module includes a first sending unit, a first receiving unit, and a first establishing unit, where:

a first sending unit, configured to send, by using the server, a NAT address and a port of the terminal, and a file transmission request carrying a file identifier to the destination terminal;

a first receiving unit, configured to receive a NAT address and a port of the destination terminal that is sent by the destination terminal by using the server, and a response message that is sent by the destination terminal to agree to receive a file; a first establishing unit, configured to pass the terminal The TCP direct connection channel is established with the respective NAT address and port of the destination terminal.

The terminal further includes an MSRP channel establishment module and a second file transmission module, where: the through channel establishment module is further configured to notify the MSRP channel establishment module when the TCP direct connection channel fails to be established;

An MSRP channel establishing module, configured to establish a source MSRP channel with the server when receiving a TCP direct channel establishment failure notification;

a second file transmission module, configured to pass the source MSRP channel and the destination terminal The destination MSRP channel between the servers performs file transfer with the destination terminal.

The MSRP channel establishment module includes a second sending unit, a second receiving unit, and a second establishing unit, where:

a second sending unit, configured to send a session request message to the destination terminal by using the server; and a second receiving unit, configured to receive a response message that is sent back by the server after the destination MSRP channel between the destination terminal and the server is successfully established;

And a second establishing unit, configured to establish a source MSRP channel with the server according to the response message.

The present invention also provides a system for transferring files between SIP terminals in a NAT network, including: a source terminal, a server, and a destination terminal, wherein the source terminal and the destination terminal are respectively connected to the server through a NAT network device;

a source terminal, configured to establish, by using the server, a TCP direct connection channel with the destination terminal; and perform file transmission with the destination terminal by using the TCP direct connection channel;

a server, configured to establish, by the NAT network device, the TCP direct connection channel between the source terminal and the destination terminal by using the source terminal;

And the destination terminal is configured to establish, by the server, the TCP direct communication channel with the source terminal, and perform file transmission with the source terminal by using the TCP direct connection channel.

The server is further configured to receive a file transfer request that is sent by the source terminal and that carries the file identifier, and obtain a NAT address and a port of the source terminal; forward the file transfer request to the destination terminal, and simultaneously use the source Sending a NAT address and a port of the terminal to the destination terminal; and forwarding a response message of the consent receiving file fed back by the destination terminal to the source terminal, and sending the NAT address and port of the destination terminal to the source terminal.

The server is an application server AS.

The invention provides a method, a terminal and a system for transferring files between SIP terminals in a NAT network, and dynamically selects a channel for file transmission based on the network topology structure of the SIP terminal, that is, when two SIPs When the terminal is in a private network behind different NAT network devices, a traversal is established between the two SIP terminals.

The TCP direct connection channel of the NAT network, so that the two-way file transmission between the two SIP terminals is realized without using the MSRP channel of the server relay, thereby effectively utilizing the network topology structure, improving the file transmission rate and reducing the file transmission rate. The occupation of the network bandwidth further reduces the load on the server, and the file transmission mode provided by the present invention supports breakpoint retransmission. Further, when the TCP direct connection channel fails to be established, the server can still switch to the server-transferred MSRP channel for file transmission, which makes the file transmission mode selective and flexible. DRAWINGS

1 is a flow chart of a first embodiment of a method for transferring files between SIP terminals in a NAT network according to the present invention;

2 is a flow chart of file transmission between a TCP direct connection channel and a destination terminal in a first embodiment of a method for transferring file between SIP terminals in a NAT network according to the present invention;

3 is a flow chart showing a second embodiment of a method for transferring files between SIP terminals in a NAT network according to the present invention;

4 is a flowchart of a source MSRP channel established between a source terminal and a server in a second embodiment of a method for transferring file between SIP terminals in a NAT network according to the present invention;

5 is a schematic structural diagram of a first embodiment of a terminal for transferring files between SIP terminals in a NAT network according to the present invention;

6 is a schematic structural diagram of a direct connection channel establishment module in a first embodiment of a terminal for transferring files between SIP terminals in a NAT network according to the present invention;

7 is a schematic structural diagram of a second embodiment of a terminal for transferring files between SIP terminals in a NAT network according to the present invention;

8 is a schematic structural diagram of an MSRP channel establishment module in a second embodiment of a terminal for transferring files between SIP terminals in a NAT network according to the present invention;

9 is a diagram of a first embodiment of a system for transferring files between SIP terminals in a NAT network according to the present invention; Schematic diagram. detailed description

The solution of the embodiment of the present invention is to dynamically enable a TCP (Transmission Control Protocol) direct connection channel or an MSRP channel to perform file transmission according to the network topology SIP terminal.

As shown in FIG. 1, a first embodiment of the present invention provides a method for file transfer between SIP terminals in a NAT network, including:

Step 101: The source terminal establishes a Transmission Control Protocol (TCP) direct connection channel with the destination terminal through the server.

Step 102: Perform file transmission with the destination terminal through the TCP direct connection channel.

The operating environment of the method of the present invention shown in Figure 1 is based on the network topology in which the SIP terminal is located in the IMS environment. In the network topology, the SIP terminals are connected to the application server (hereinafter referred to as the server) through the respective NAT network devices. In the prior art, most of the SIP terminals in the IMS environment use the MSRP channel mode of the server to transfer files. Transmission, which does not effectively support file transfer for SIP terminals in different subnets, that is, the SIP terminals in the private network behind different NAT network devices can only transmit files through the MSRP channel relayed by the server. The file transfer method has the disadvantage of occupying a large amount of network bandwidth for a long time when transferring large files, and the transfer speed is extremely susceptible to server performance and network bandwidth.

How to achieve efficient file transfer between SIP terminals and minimize the bandwidth usage of the Internet/Intranet network is a problem to be solved by the present invention.

In the first embodiment, two SIP terminals that need to perform file transmission in the private network behind different NAT network devices are respectively referred to as a source terminal and a destination terminal, and in order to directly perform file transmission between the source terminal and the destination terminal, Establish a TCP direct connection channel between the source terminal and the destination terminal. Through the TCP direct connection channel, the source terminal and the destination terminal can implement file transmission without passing through the MSRP channel of the server transit, thereby effectively utilizing the network topology and improving the network topology. File transfer The rate reduces the occupation of network bandwidth and reduces the load on the server.

As shown in FIG. 2, the specific implementation of step 101 in FIG. 1 includes:

Step 1021: The source terminal sends its own NAT address and port, and a file transfer request carrying the file identifier to the destination terminal through the server.

Step 1022: After receiving the file transmission request, the destination terminal sends its own NAT address and port through the server, and a response message to the source terminal that agrees to receive the file.

Step 1023: Establish a TCP direct connection channel through the NAT address and port of the source terminal and the destination terminal.

In the above steps 1021 to 1023, the source terminal and the destination terminal are connected to the server through respective NAT network devices (hereinafter referred to as source NAT and destination NAT respectively), that is, the source terminal is behind the source NAT, and the destination terminal is behind the destination NAT. The source terminal and the destination terminal exchange file transfer information and their respective NAT addresses and ports through the server. The process of establishing a TCP direct connection channel between the source terminal and the destination terminal is specifically as follows:

First, the source terminal needs to send the file transmission request to the destination terminal. To this end, the server needs to start two port listening, that is, primary listening and auxiliary listening; and each terminal needs to keep in touch with the server's main listening. . The source terminal sends a file transfer request to the secondary listening port of the server. The file transfer request includes a file identifier, and the server obtains the NAT address and port of the source terminal after the source NAT is converted.

After that, the server forwards the file transmission request sent by the source terminal to the destination terminal through the primary listening port, and sends the source terminal to the destination terminal through the source NAT-transformed NAT address and port. The destination terminal forwards the response message agreeing to receive the file to the source terminal through the primary listening port of the server.

Then, the destination terminal actively establishes a connection to the secondary listening port of the server, and forwards the NAT address and port of the destination terminal through the destination NAT to the source terminal through the server.

At this time, the destination terminal attempts to connect to the NAT address and port of the source terminal, and the connection is in the normal situation. In the case of failure, the source NAT will record the source address and port of the connection, ready for the next real connection, the so-called hole punching, that is, the destination terminal makes a hole to the source terminal, so that The next time the source terminal can connect to the NAT address and port that the destination terminal just used. At the same time, the destination terminal starts monitoring on the local port, and sends a notification to the source terminal to receive the file through the server.

The server sends a notification to the source terminal that the destination terminal is ready to receive the file, and sends the NAT address and port of the destination terminal that has been translated by the destination NAT to the source terminal. The source terminal tries to connect to the NAT address and port of the destination terminal. Because the destination terminal has tried to connect to the NAT address and port of the source terminal in the above steps, and the source NAT records the information of the connection, when the source terminal actively connects to the destination terminal, The destination NAT considers that the connection request is a valid connection request, and allows the connection to pass, so that the TCP direct connection channel between the source terminal and the destination terminal is successfully established. The source terminal and the destination terminal can use the TCP direct connection channel for high-speed file transmission, and the file transmission mode not only supports breakpoint resume transmission, but also realizes two-way file transmission.

It should be noted that, in this embodiment, the server may be an application server (AS) or another application server.

In this embodiment, when the two SIP terminals are in the private network behind the different NAT network devices, a TCP direct connection channel traversing the NAT network is established between the two SIP terminals, and the MSRP channel of the server is not required to be transited. The two-way file transmission between the two SIP terminals is realized, thereby effectively utilizing the network topology structure, improving the file transmission rate, reducing the occupation of the network bandwidth, further reducing the load of the server, and supporting the file transmission mode. http.

As shown in FIG. 3, in a second embodiment of the present invention, a method for file transfer between SIP terminals in a NAT network is provided, including:

Step 301: The source terminal establishes a TCP direct connection channel with the destination terminal through the server. If the establishment is successful, the process proceeds to step 302; otherwise, the process proceeds to step 303.

Step 302: The source terminal performs file transmission with the destination terminal through the TCP direct connection channel, and ends. This process.

Step 303: The source terminal establishes a source MSRP channel with the server.

Step 304: The source terminal performs file transmission with the destination terminal through the source MSRP channel and the destination MSRP channel between the destination terminal and the server.

The steps 301 and 302 are the same as the steps 101 and 102 of the embodiment shown in FIG. 1. The step S302 is the same as the step 102 of the foregoing embodiment, and details are not described herein again.

On the basis of the first embodiment, the second embodiment adds a step of performing file transmission by the source terminal and the destination terminal through the MSRP channel relayed by the server when the TCP direct connection channel between the source terminal and the destination terminal fails to be established. The normal communication between the source terminal and the destination terminal is further ensured.

As shown in FIG. 4, the specific implementation of the source MSRP channel between the source terminal and the server in step 303 includes the following steps:

Step 3031: The source terminal sends a session request message to the destination terminal through the server.

Step 3032: After the destination MSRP channel between the destination terminal and the server is successfully established, the server feeds back a response message from the destination terminal to the source terminal.

Step 3033: The source terminal establishes a source MSRP channel with the server according to the response message. In the second embodiment, when the source terminal and the destination terminal fail to establish a TCP direct connection channel, the process of switching to the MSRP channel of the server for file transmission is specifically as follows:

First, the source terminal sends a session message invite ( sdpl ) to the server, and the server forwards the invite (sdpr) to the destination terminal; after receiving the invite (sdpr), the destination terminal sends a response 200 OK (sdp2) to the server; the server receives the destination terminal. After the response 200OK ( sdp2 ), the confirmation message (ACK) is sent to the destination terminal;

Then, the destination terminal actively sends a link establishment request to the server; the MSRP channel between the destination terminal and the server is successfully established; Then, the server sends a 200 OK (sdp2) to the source terminal; the source terminal sends an acknowledgement message ACK to the server; the source terminal actively sends a link establishment request to the server; the MSRP channel between the source terminal and the server is successfully established;

Finally, the source terminal starts to send the file content to the server; the server forwards the file content to the destination terminal; the source terminal sends the file content successfully; and the destination terminal receives the file content successfully.

In the second embodiment, after the source terminal and the destination terminal successfully transmit the file through the MSRP channel relayed by the server, the source terminal and the destination terminal respectively release the MSRP channel and the session between the server and the server.

In the second embodiment, as described above, the source terminal and the destination terminal are in different NAT environments. Therefore, when the source terminal and the destination terminal perform file transmission, first try to establish a TCP direct connection channel through the NAT, if the TCP is straight. If the channel is successfully established, the file is transmitted through the TCP direct connection channel. If the TCP direct connection channel cannot be established, the MSRP channel of the server relay is enabled, and the file is transmitted through the MSRP channel of the server transit.

The second embodiment provides a method for dynamically enabling a TCP direct connection channel or an MSRP channel for file transmission according to a network topology SIP terminal, that is, when two SIP terminals are in a private network behind different NAT network devices, in the two SIPs A TCP direct connection channel traversing the NAT network is established between the terminals, and the two-way file transmission between the two SIP terminals can be realized without using the MSRP channel relayed by the server, thereby effectively utilizing the network topology structure and improving file transmission. The rate reduces the occupation of the network bandwidth, further reduces the load on the server, and the file transmission mode supports breakpoint retransmission. Further, when the above TCP direct connection channel fails to be established, the MSRP channel that is transferred to the server can still be switched to perform file transmission, so that the file transmission mode is selective and flexible.

As shown in FIG. 5, a schematic structural diagram of a first embodiment of a terminal for file transfer between SIP terminals in a NAT network according to the present invention includes: a direct connection channel establishing module 501 and a first file transmission module 502, wherein:

The direct connection channel establishing module 501 is configured to establish a TCP between the destination terminal and the destination terminal through the server. Direct connection channel;

The first file transmission module 502 is configured to perform file transmission with the destination terminal through the TCP direct connection channel.

As shown in FIG. 6, the direct connection channel establishing module 501 includes:

The first sending unit 5011 is configured to send, by using a server, a NAT address and a port of the terminal, and a file transmission request carrying the file identifier to the destination terminal;

The first receiving unit 5012 is configured to receive a NAT address and a port of the destination terminal sent by the destination terminal, and a response message of the consent receiving file fed back by the destination terminal. The first establishing unit 5013 is configured to pass the source terminal and the destination. The TCP direct connection channel is established by the terminal's respective NAT address and port.

In this embodiment, the source terminal and the destination terminal are both SIP terminals in the IMS environment, and the SIP terminals are connected to the application server (hereinafter referred to as the server) through the respective NAT network devices. In the prior art, the SIP terminals in the IMS environment are mostly single. The file transfer is performed by using the MSRP channel mode of the server. This is not effective for file transfer of SIP terminals in different subnets. That is, SIP terminals in the private network behind different NAT network devices can only transit through the server. The MSRP channel performs file transfer. This file transfer method has the disadvantage of occupying a large amount of network bandwidth for a long time when transferring large files, and the transfer speed is highly susceptible to server performance and network bandwidth.

In this embodiment, in order to implement efficient file transmission between the terminal and the destination terminal, to minimize the bandwidth occupation ratio of the Internet/Intranet network, a TCP direct connection channel between the terminal and the destination terminal needs to be established, and the TCP directly connects the channel, the terminal and the The destination terminal can implement file transmission without using the MSRP channel relayed by the server, thereby effectively utilizing the network topology structure, increasing the file transmission rate, reducing the occupation of the network bandwidth, and reducing the load on the server.

Hereinafter, the terminal is referred to as a source terminal in this embodiment as an example to describe the relationship between the source terminal and the destination terminal.

TCP direct connection channel establishment process: First, the source terminal needs to send the file transmission request to the destination terminal. To this end, the server needs to start two port listening, that is, primary listening and auxiliary listening; and each terminal needs to keep in touch with the server's main listening. . The source terminal sends a file transfer request to the secondary listening port of the server. The file transfer request includes a file identifier, and the server obtains the NAT address and port of the source terminal after the source NAT is translated.

After that, the server forwards the file transfer request sent by the source terminal to the destination terminal through the primary listening port, and sends the source terminal to the destination terminal through the source NAT-transformed NAT address and port. The destination terminal forwards the response message agreeing to receive the file to the source terminal through the primary listening port of the server.

At this point, the destination terminal attempts to connect to the source terminal's NAT address and port. The connection will fail normally, but the source NAT will record the source address and port of the connection, ready for the next real connection. The so-called hole punching, that is, the destination terminal makes a hole to the source terminal, so that the next source terminal can connect to the NAT address and port that the destination terminal just used. At the same time, the destination terminal starts monitoring on the local port, and sends a notification to the source terminal to receive the file through the server.

The server sends a notification to the source terminal that the destination terminal is ready to receive the file, and sends the destination NAT-transformed NAT address and port to the source terminal. The source terminal tries to connect to the NAT address and port of the destination terminal. In the above step, the destination terminal attempts to connect to the NAT address and port of the source terminal, and the source NAT records the information of the connection. Therefore, when the source terminal actively connects to the destination terminal, The destination NAT considers that the connection request is a valid connection request, and allows the connection to pass, so that the TCP direct connection channel between the source terminal and the destination terminal is successfully established. The source terminal and the destination terminal can use the TCP direct connection channel for high-speed file transmission, and the file transmission mode not only supports breakpoint continuous transmission, but also realizes two-way file transmission. It should be noted that, in this embodiment, the server may be an application server AS, or may be another application server.

In this embodiment, when the terminal and the destination terminal are located in a private network behind different NAT network devices, a TCP direct connection channel traversing the NAT network is established between the two SIP terminals, and the MSRP channel that is transited by the server is not required. The two-way file transmission between the two SIP terminals can be realized, thereby effectively utilizing the network topology structure, improving the file transmission rate, reducing the occupation of the network bandwidth, further reducing the load of the server, and the file transmission mode. Support for breakpoints.

As shown in FIG. 7, a schematic structural diagram of a second embodiment of a terminal for file transfer between SIP terminals in a NAT network according to the present invention includes: a direct connection channel establishment module 701 and a connection with the direct connection channel establishment module 701 a file transmission module 702, an MSRP channel establishment module 703, and a second file transmission module 704 connected to the MSRP channel establishment module 703, wherein: a direct connection channel establishment module 701 is configured to establish a TCP direct connection with the destination terminal through the server. When the TCP direct connection channel fails to be established, the MSRP channel establishment module 703 is notified; the first file transmission module 702 is configured to perform file transmission with the destination terminal through the TCP direct connection channel;

The MSRP channel establishing module 703 is configured to establish a source MSRP channel with the server when receiving a notification of a TCP direct channel establishment failure.

The second file transmission module 704 is configured to perform file transmission between the source MSRP channel and the destination MSRP channel and the destination terminal between the destination terminal and the server.

In FIG. 7, the direct connection channel establishment module 701 has the same functional structure as the direct connection channel establishment module 501 in FIG. 5, and details are not described herein again.

As shown in FIG. 8, the MSRP channel establishment module 703 includes:

The second sending unit 7031 is configured to send a session request message to the destination terminal by using the server. The second receiving unit 7032 is configured to receive a response message that is sent back by the server after the destination MSRP channel between the destination terminal and the server is successfully established. The second establishing unit 7033 is configured to establish a source MSRP channel with the server according to the response message.

On the basis of the foregoing embodiment, the present embodiment further solves the problem that when the TCP direct connection channel between the source terminal and the destination terminal fails to be established, the source terminal and the destination terminal perform file transmission through the MSRP channel relayed by the server. This ensures proper communication between the source terminal and the destination terminal.

As shown in FIG. 9, an embodiment of the present invention provides a system for file transmission between SIP terminals in a NAT network, including: a source terminal 901, a server 902, and a destination terminal 903, and the source terminal 901 and the destination terminal 902 respectively pass through a NAT network device. The server 902 is connected to the server 902. The source terminal 901 is connected to the server 902 through the source NAT network device 9012. The destination terminal 902 is connected to the server 902 through the destination NAT network device 9023.

The source terminal 901 is configured to establish a TCP direct connection channel with the destination terminal 903 through the server 902; and perform file transmission with the destination terminal 902 through the TCP direct connection channel;

The server 902 is configured to establish, by using the NAT network device, the source terminal 901 to establish a TCP direct connection channel between the source terminal 901 and the destination terminal 903.

The destination terminal 903 is configured to establish a TCP direct channel with the source terminal 901 through the server 902; and perform file transmission with the source terminal 901 through the TCP direct connection channel.

In this embodiment, the server 902 is further configured to receive the file transfer request that carries the file identifier sent by the source terminal 901, and obtain the NAT address and port of the source terminal 901; forward the file transfer request to the destination terminal 903, and simultaneously source the source The NAT address and port of the terminal 901 are sent to the destination terminal 903; and the response message of the consent receiving file fed back by the destination terminal 903 is forwarded to the source terminal 901, and the NAT address and port of the destination terminal 903 are sent to the source terminal 901.

The server 902 of this embodiment may be an application server AS; the source terminal 901 may be the terminal described in the above embodiment.

Embodiments of the present invention dynamically select file transmission based on a network topology in which a SIP terminal is located The channel, that is, when the two SIP terminals are in the private network behind different NAT network devices, the TCP direct connection channel that traverses the NAT network is established between the two SIP terminals, and the MSRP channel that is transited by the server does not need to be implemented. Two-way file transfer between the two SIP terminals, thereby effectively utilizing the network topology structure, improving the file transfer rate, reducing the occupation of the network bandwidth, further reducing the load on the server, and the file transfer mode supports breakpoints. Continued transmission. Further, when the above TCP direct connection channel fails to be established, the file transfer can still be switched to the MSRP channel of the server relay, so that the file transmission mode is selective and flexible.

The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and equivalent structural or process changes made by the present specification and drawings may be directly or indirectly applied to other related technical fields. The same is included in the scope of patent protection of the present invention.

Claims

Claim

A network address translation method in a NAT network. The method for transmitting a file between SIP terminals is characterized in that: the source terminal establishes a transmission control protocol TCP direct connection channel with the destination terminal through the server;

The method according to claim 1, wherein the establishing, by the source terminal, the TCP direct connection channel between the source terminal and the destination terminal comprises:

The source terminal sends a NAT address and port, and a file transmission request carrying the file identifier to the destination terminal through the server;

The method according to claim 1 or 2, wherein after the source terminal establishes a TCP direct connection channel with the destination terminal through the server, the method further includes:

The method according to claim 3, wherein the source terminal establishes a source MSRP channel with the server, and specifically includes:

Sending, by the server, a session request message to the destination terminal by using a server;

The remote terminal establishes a source MSRP connection with the server according to the response message. Road.

A terminal for transferring files between SIP terminals in a NAT network, comprising: a direct channel establishing module and a first file transmitting module, wherein:

The terminal according to claim 5, wherein the direct channel establishing module comprises a first sending unit, a first receiving unit and a first establishing unit, wherein: and a file transmission request carrying the file identifier is sent To the destination terminal;

The terminal according to claim 5 or 6, wherein the terminal further includes an MSRP channel establishment module and a second file transmission module, where:

The through channel establishing module is further configured to notify the MSRP channel establishing module when the TCP direct connection channel fails to be established;

And a second file transmission module, configured to perform file transmission with the destination terminal by using the source MSRP channel and the destination MSRP channel between the destination terminal and the server.

The terminal according to claim 7, wherein the MSRP channel establishment module comprises a second sending unit, a second receiving unit, and a second establishing unit, where: a second sending unit, configured to send a session request message to the destination terminal by using the server; and a second receiving unit, configured to receive a response message that is sent back by the server after the destination MSRP channel between the destination terminal and the server is successfully established;

A system for transferring files between SIP terminals in a NAT network, comprising: a source terminal, a server, and a destination terminal, wherein the source terminal and the destination terminal are respectively connected to the server through a NAT network device;

The system according to claim 9, wherein the server is further configured to receive a file transmission request that is sent by the source terminal and that carries the file identifier, and obtain a NAT address and a port of the source terminal; Sending a file transfer request to the destination terminal, and transmitting the NAT address and port of the source terminal to the destination terminal; and forwarding a response message of the consent receiving file fed back by the destination terminal to the source terminal, and simultaneously Sending the NAT address and port of the destination terminal to the source terminal.

11. System according to claim 9 or 10, characterized in that the server is an application server AS.

The system according to claim 11, wherein the source terminal is the terminal according to any one of claims 5 to 8.