WO2015096302A1

WO2015096302A1 - Nat traversal method based on sip media capability re-negotiation, proxy server and system

Info

Publication number: WO2015096302A1
Application number: PCT/CN2014/075265
Authority: WO
Inventors: 姚刚; 张强; 刘志鹏
Original assignee: 中兴通讯股份有限公司
Priority date: 2013-12-25
Filing date: 2014-04-14
Publication date: 2015-07-02
Also published as: CN103916382A; CN103916382B

Abstract

An NAT traversal method based on an SIP media capability re-negotiation, a proxy server and a system. At least one of a first terminal and a second terminal is located in a private network, and the proxy server is located in a public network. The method comprises: receiving, by a proxy server, media code streams coming from a first terminal and a second terminal respectively, and acquiring public network addresses and public network port numbers of the first terminal and the second terminal; and initiating, by the proxy server, a media capability re-negotiation, notifying the second terminal of the acquired public network address and public network port number of the first terminal, and notifying the first terminal of the acquired public network address and public network port number of the second terminal.

Description

NAT traversal method, proxy server and system based on SIP media capability renegotiation

The present invention relates to the field of NAT traversing technology, and in particular to a NAT traversal method, a proxy server and a system based on SIP media capability re-coordination. Background technique

The existing SIP (Session Initiation Protocol) traversal NAT (Network Address Translation) technology is mainly based on the following ideas: The SIP signaling channel passes through the NAT through the registration request of the terminal, and is subsequently maintained by the registration refresh. Signaling channel. All subsequent signaling messages sent by the terminal share the registration channel transmission, and the server transmits the message along the reverse path of the registration channel. The media stream also uses a similar technology. First, the terminal sends an RTP (eal-time transport protocol) packet to the server. The NAT will open a port for the RTP stream, and then the server will follow the direction of the RTP stream. The path sends a TP packet.

Currently, there are several options for NAT traversal technology:

STU (Simple Traversal of UDP over NATs) protocol, the terminal interacts with the STU server to determine the public network address and port number assigned to them by the NAT;

2. The TURN (traversal using Relay NAT) protocol is a way to pass through the NAT through the relay mode. The packets sent by the private network terminal are relayed and forwarded by the TURN server.

3. ICE (Interactive Connectivity Establishment) is a comprehensive solution that selects the transmission channel through connectivity testing. It provides a framework that enables various NAT penetration technologies to be unified; 4. The SBC (Session Border Controller) is a relatively complete solution. It does not require any requirements on the original network. It does not require any modification of the terminal. The signaling and media streams of the terminal need to pass through the SBC. Media forwarding.

The above scheme has the following shortcomings:

1. The existing network needs to be modified. According to the above different NAT traversal technology, the terminal must support the STU, TURN or ICE protocol, and deploy the traversal server (unlike the normal NAT device, it needs to be deployed independently), which implements STUN or TURN server or SBC functions are costly.

2. It is necessary to traverse the server for media stream forwarding, and it is impossible to establish a direct media stream between terminals. Summary of the invention

To solve the existing technical problems, the embodiments of the present invention provide a NAT traversal method, a proxy server, and a system based on SIP media capability renegotiation.

The embodiment of the present invention provides a method for NAT traversal based on SIP media capability re-negotiation. At least one of the first terminal and the second terminal is located on the private network, and the proxy server is located on the public network. The method includes:

The proxy server receives the media code streams from the first terminal and the second terminal, respectively, and obtains the public network address and the public network port number of the first terminal and the second terminal;

The proxy server initiates the media capability renegotiation, and notifies the obtained public network address and the public network port number of the first terminal to the second terminal, and obtains the public network address of the second terminal and the public network. The port number is notified to the first terminal.

The embodiment of the invention further provides a proxy server, where the proxy server is located on the public network, and includes:

An acquiring module, configured to receive a media code stream from the first terminal and the second terminal, respectively, and obtain a public network address and a public network port number of the first terminal and the second terminal; the first terminal and the second terminal At least one of the terminals is located on the private network;

a media capability renegotiation module, configured to initiate a media capability renegotiation, to notify the second terminal of the acquired public network address and the public network port number of the first terminal, and obtain the public network of the second terminal The address and the public network port number are notified to the first terminal.

The embodiment of the present invention further provides a NAT traversal system based on SIP media capability re-negotiation, including the foregoing proxy server, the first terminal, and the second terminal, where:

The proxy server is configured to receive the media code streams from the first terminal and the second terminal respectively, and obtain the public network address and the public network port number of the first terminal and the second terminal; Notifying, to the second terminal, the obtained public network address and the public network port number of the first terminal, and notifying the obtained public network address and the public network port number of the second terminal to the first terminal Terminal

The first terminal is configured to send a media code stream to a public network address and a public network port number of the second terminal;

The second terminal is configured to send a media code stream to a public network address and a public network port number of the first terminal.

An embodiment of the present invention further provides a NAT traversal device based on SIP media capability re-negotiation, where the device includes a hardware processing server, where:

The hardware processing server is configured to receive the media code streams from the first terminal and the second terminal respectively, and obtain the public network address and the public network port number of the first terminal and the second terminal; Re-negotiating, notifying the obtained second network address and the public network port number of the first terminal to the second terminal, and notifying the obtained public network address and the public network port number of the second terminal to the a terminal.

In the NAT traversal method, the proxy server, and the system based on the SIP media capability re-negotiation, at least one of the first terminal and the second terminal is located in the private network, and the proxy server is located in the public network; the proxy server receives the first from the first a media stream of the terminal and the second terminal, and obtaining a public network address and a public network port number of the first terminal and the second terminal; the proxy server initiates the media The capability re-negotiation is to notify the second terminal of the obtained public network address and the public network port number of the first terminal, and notify the first terminal of the obtained public network address and public network port number of the second terminal. After that, the first terminal and the second terminal can directly communicate based on the public network address of the opposite party and the public network port number, and do not need to be forwarded by the proxy server; in addition, the implementation of the foregoing technical solution is based on the existing network architecture, and does not need to be performed thereon. Improvements, as well as direct communication between terminals without the need to set up a dedicated traversal server, saves costs. DRAWINGS

FIG. 1 is a schematic diagram of a NAT traversal process based on SIP media capability re-negotiation according to an embodiment of the present invention;

2 is a schematic diagram of media capability negotiation according to Embodiment 1 of the present invention;

3 is a schematic diagram of receiving a media code stream by a proxy server according to Embodiment 1 of the present invention;

4 is a schematic diagram of media capability re-negotiation according to Embodiment 1 of the present invention;

FIG. 5 is a schematic diagram of media capability negotiation according to Embodiment 2 of the present invention;

6 is a schematic diagram of a proxy server receiving a media code stream according to Embodiment 2 of the present invention;

FIG. 7 is a schematic diagram of media capability re-negotiation according to Embodiment 2 of the present invention;

FIG. 8 is a schematic structural diagram of a proxy server according to an embodiment of the present disclosure;

FIG. 9 is a schematic diagram of a NAT traversal system based on SIP media capability re-negotiation according to an embodiment of the present invention. detailed description

The technical solutions of the present invention are further elaborated below in conjunction with the accompanying drawings and specific embodiments. In the actual application scenario of SIP conference TV, a certain range of media port numbers are required to be opened, so most of the terminals and MCU (Micro Controller Unit) devices are in Full Cone NAT. , that is, the request sent by the same media private network address and media private network port number will be mapped to the same media public network address and The media public network port number, and any public network device can send packets to the private network device through the mapped media public network address and the media public network port number. In addition, the media stream transceiver port of the terminal is the same, that is, transmitting and receiving on the same port. The addresses and ports (private network, public network) involved in the embodiments of the present invention are both the media stream stream sending and receiving addresses and ports, unless otherwise specified.

Based on these characteristics, the terminal device can be notified by means of media capability renegotiation to inform the peer of the media stream to send and receive addresses and port numbers. As long as the terminal does not change the media stream transceiver port of the local end during media capability renegotiation, NAT traversal of the media code stream can be implemented. The general process is as follows: The proxy server (which is a mandatory network element in the SIP conference system, responsible for terminal registration, signaling forwarding, etc., which does not have the NAT traversal function itself) receives the first transmission by the first terminal. The media stream data packet learns the public network address and the public network port number of the terminal, and then, on the corresponding call session, the proxy server initiates media capability re-negotiation (reinvite message or update message) to the opposite terminal (second terminal). The corresponding SDP (Session Description Protocol) information carries the public network address of the first terminal and the public network port number. In the same manner, the proxy server receives the first media stream packet of the second terminal. Then, the media capability re-negotiation is also initiated to the first terminal, and the corresponding SDP information carries the public network address and the public network port number of the second terminal, so that the media capability re-negotiation is completed. After that, the first terminal and the second terminal can directly send the media code stream through the public network address and the public network port number of the other party, and do not need to be forwarded by the proxy server, thereby realizing direct transmission of the media code stream between the terminals, thereby greatly improving efficiency. And the above process is based on the existing network architecture, eliminating the need to deploy a dedicated traversal server, saving costs.

In order to achieve NAT traversal of the media stream without modifying the existing network equipment, and without media transit through the server, directly establish a media stream between the calling and called terminals, reduce the load across the server, and reduce the data. The delay of the transmission improves the efficiency of the data transmission. The embodiment of the present invention provides a NAT traversal scheme based on SIP media capability renegotiation, in which: at least one of the first terminal and the second terminal is located in the private network, the proxy The server is located on the public network. As shown in Figure 1, the detailed implementation process includes: Step 101: The proxy server receives the media code streams from the first terminal and the second terminal, respectively, and obtains a public network address and a public network port number of the first terminal and the second terminal.

During the media capability negotiation process, the proxy server assigns a port number to the first terminal and the second terminal, and notifies the second terminal of the port number assigned to the first terminal, and notifies the port number assigned to the second terminal to the second terminal. a terminal

The proxy server listens on the port number assigned to the second terminal, and receives the media code stream from the first terminal; listens to the port number assigned to the first terminal, and receives the media code stream from the second terminal;

The proxy server extracts and records the public network address and the public network port number of the first terminal or the second terminal from the media code stream from the first terminal or the second terminal (the media code stream here is the first terminal and the second terminal The first media stream sent by the proxy server) specific:

When the first terminal or the second terminal is located in the private network, the public network address and the public network port number of the first terminal or the second terminal are converted by the corresponding private network address and the private network port number, specifically: in the NAT device. When the media stream sent by the first terminal or the second terminal to the proxy server is intercepted, the source address and the source port number (that is, the private network address and the private network port number) are converted into a public network address and a public network port number;

When the first terminal or the second terminal is located on the public network, the source address and the source port number of the corresponding media code stream are the public network address and the public network port number of the first terminal or the second terminal.

Preferably, the proxy server establishes a mapping relationship between the public network address of the first terminal, the public network port number, the public network address of the second terminal, and the public network port number.

The foregoing media capability negotiation process includes: the proxy server receives the request message from the first terminal, allocates a port number to the first terminal, and forwards the request message to the second terminal; and the request message forwarded to the second terminal carries the proxy server a network address and a port number assigned to the first terminal; the proxy server receives the response message from the second terminal, assigns a port number to the second terminal, and forwards the response message to the first terminal; and forwards the response message to the first terminal The public network address carrying the proxy server and the port number assigned to the second terminal. Step 102: The proxy server initiates the media capability renegotiation, and notifies the obtained second public terminal address and the public network port number of the first terminal to the second terminal, and notifies the obtained public network address and public network port number of the second terminal to the second terminal. a terminal.

In the embodiment of the present invention, the proxy server initiates media capability re-negotiation to the first terminal and the second terminal by using the request message; the request message sent to the first terminal carries the public network address and the public network port number of the second terminal; The request message to the second terminal carries the public network address and the public network port number of the first terminal.

The following technical solution is further illustrated by taking a terminal point-to-point call in two scenarios as an example.

Scenario 1: Terminal A is in a fully conical NAT, and terminal B and Proxy (proxy server) are located in the public network.

In this scenario, the implementation process of direct media code stream transmission between terminals A and B includes the following stages: 1. media capability negotiation between terminals; 2. proxy server receives media code stream; 3 media capability re-negotiation between terminals .

Figure 2 shows the media capability negotiation process between terminals, including:

(1) The terminal A initiates a request call (for example, the request message may be an Invite message), and the SDP information carries the local media capability. The information describing the media capabilities in the SDP information of the embodiment of the present invention is: c lines, m lines. Among them, the c line carries the connection information; the m line carries the media name and the transmission address. In this step, the c line carries the local address of the terminal A (here, the private network address of the terminal A), and the m line carries the local port number of each type of media stream (such as audio, video, picture, etc.) of the terminal A (here Terminal A's private network port number).

The Invite message reaches the Proxy through the NAT device. Because the media stream has not been established, the proxy cannot obtain the public network address and public network port number of the terminal A. In order to allow the media code stream from the terminal A to pass the proxy, the proxy allocates a new terminal A. The port number, then the proxy needs to forward the Invite message to the terminal B: Since the terminal B and the proxy are located in the public network, the Proxy already knows the address and port number of the terminal B during the registration phase (here, the signaling address and port) Number, with the media The sending and receiving addresses are different from the port number. Therefore, the Proxy can directly forward the Invite message from the terminal A to the terminal B. In the Invite message forwarded to the terminal B, the SDP information in the C line carries the address replaced with the public network address of the Proxy, and the port number carried in the m line is replaced with the new port number assigned by the Proxy to the terminal A.

(2) After receiving the Invite message forwarded by the Proxy, the terminal B returns a response message (for example, a 200 OK message) to the Proxy, where the SDP information c line carries the local address of the terminal B (here, the public network address), and the m line carries The local port number of terminal B (here, the public network port number).

Return 200 OK message directly to the Proxy. Since the media stream has not been established, the Proxy cannot obtain the public network address and the public network port number of the terminal B. In order to allow the media stream from the terminal B to pass the Proxy, the Proxy assigns a new port number to the terminal B, and then sets the 200 OK. The message is forwarded to the terminal A. The public network address of the terminal B carried in the C line of the SDP information is replaced with the public network address of the proxy. The public network port number of the terminal B carried in the m line is replaced with the new one assigned by the proxy to the terminal B. The port number.

(3) After the terminal A receives the 200 OK message forwarded by the proxy, the media capability negotiation between the terminals A and B is completed, the terminal A returns a response message (for example, an ACK message), and the proxy forwards the ACK to the terminal B, and the call connection is established.

After the media capability negotiation process shown in FIG. 2, the Proxy starts listening on the port allocated for the terminal B, and receives the media code stream from the terminal A; listens on the port allocated for the terminal A, and receives the media code from the terminal B. Flow, the process of receiving the media code stream by the proxy server as shown in FIG. 3:

(1) The terminal A sends the media code stream to the public network address of the Proxy and the port allocated by the Proxy to the terminal B according to the description of the SDP in the 200 OK message; and simultaneously listens to the local port at the local address (that is, the private network address) (ie, Private network port).

The media code stream sent by the terminal A needs to reach the Proxy through the NAT device. After the NAT device intercepts the media code stream sent by the terminal A, the source address (that is, the local address of the terminal A, in this embodiment is the private network address) and the source port. Number (that is, the local port number of terminal A. This embodiment is the private network end. The slogan is converted to obtain the public network address and the public network port number. After receiving the media code stream sent by the terminal A, the proxy records the mapping relationship between the converted public network address, the public network port number, and the terminal A.

The Proxy discards the first media stream packet and does not forward it.

(2) The terminal B sends the media code stream to the public network address of the Proxy and the port allocated by the proxy to the terminal A according to the description of the SDP in the Invite message. At the same time, the local port (that is, the public network address) listens to the local port (that is, the public). Network port ;).

The media stream sent by the terminal B can directly reach the proxy. After receiving the media stream sent by the terminal B, the proxy records the source address and the source port number of the media stream, that is, the public network address and the public network port number of the terminal B. , the media stream packet Proxy is also not forwarded.

The proxy maps the recorded terminal A and the public network address, the public network port number, the public network address of the terminal B, and the public network port number, and records the mapping.

After the process of receiving the media code stream by the proxy server shown in FIG. 3, the media capability renegotiation process shown in FIG. 4 is performed:

In order to notify the other party of the public network address and the public network port number of the terminals A and B, the proxy initiates media capability renegotiation to the terminals A and B respectively through a request message (for example, a reinvite message).

The Proxy sends a reinvite message to the terminal A. The c line of the SDP information carries the public network address of the terminal B, and the m line carries the public network port number of the terminal B.

The Proxy sends a reinvite message to the terminal B. The c line of the SDP information carries the public network address of the terminal A, and the m line carries the public network port number of the terminal A.

At this point, the media capacity has been re-negotiated.

After the media capability re-negotiation between the terminal A and the terminal B is completed, the address and port number of the media stream of the opposite end are updated, and the subsequent terminals A and B can directly send the media code stream to the media stream of the opposite end to send and receive addresses and ports. The number can be achieved, the media stream of NAT is traversed, and no need to be forwarded by Proxy. Scenario 2: Terminal A and terminal B are in a fully conical NAT, and the Proxy is located in the public network. In this scenario, the implementation process of direct media code stream transmission between terminals A and B includes the following stages: 1. media capability negotiation between terminals; 2. proxy server receives media code stream; 3 media capability re-negotiation between terminals .

Figure 5 shows the media capability negotiation process between terminals, including:

(1) Terminal A initiates an Invite call, and the SDP information carries the local media capability. The c-line carries the local address of the terminal A (here, the private network address of the terminal A), and the m-line carries the local port number of each type of media stream (such as audio, video, picture, etc.) of the terminal A (here, the private address of the terminal A) Network port number).

The Invite message reaches the Proxy through the NAT device. Because the media stream has not been established, the proxy cannot obtain the public network address and the public network port number sent and received by the media stream of the terminal A. In order to allow the media stream from the terminal A to pass the Proxy, Proxy A new port number is assigned to terminal A, and then the proxy needs to forward the Invite message to terminal B, and the message arrives at terminal B through the NAT device. The SDP information in the Invite message forwarded to the terminal B is replaced by the public network address of the proxy. The port number carried in the m line is replaced with the new port number assigned by the proxy to the terminal A.

(2) After receiving the Invite message forwarded by the proxy, the terminal B returns a 200 OK message to the Proxy, where the SDP information c line carries the local address of the terminal B (here, the private network address), and the m line carries the local port of the terminal B. No. (here is the private network port number).

The 200 OK message arrives at the Proxy through the NAT device. Since the media stream has not been established, the proxy cannot obtain the public network address and the public network port number of the terminal B. In order to allow the media code stream from the terminal B to pass the proxy, the proxy allocates the terminal B. The new port number is then forwarded to the terminal A via the NAT device. The SDP information in the 200 OK message forwarded to the terminal A is changed to the public network address of the proxy, and the port number carried in the m line is replaced with the new port number assigned by the proxy to the terminal B.

(3) After the terminal A receives the 200 OK message, the media capability negotiation between the terminals A and B is completed, the terminal A returns an ACK message, the proxy forwards the ACK to the terminal B, and the call connection establishment is completed. After the media capability negotiation process shown in FIG. 5, the Proxy starts listening on the port allocated for the terminal B, and receives the media code stream from the terminal A; listens on the port allocated for the terminal A, and receives the media code from the terminal B. Flow, the process of receiving the media code stream by the proxy server as shown in FIG. 6:

The media code stream sent by the terminal A needs to reach the Proxy through the NAT device. After the NAT device intercepts the media code stream sent by the terminal A, the source address (that is, the local address of the terminal A, in this embodiment is the private network address) and the source port. The number (that is, the local port number of the terminal A, which is the private network port number) is converted to obtain the public network address and the public network port number. After receiving the media code stream sent by the terminal A, the proxy records the converted public code. The mapping between the network address and the public network port number and terminal A.

The Proxy discards the first media stream packet and does not forward it.

(2) The terminal B sends the media code stream to the public network address of the Proxy and the port allocated by the proxy to the terminal A according to the description of the SDP in the Invite message. At the same time, the local port (that is, the private network address) listens to the local port (that is, the private port). Network port).

The media code stream sent by the terminal B needs to reach the Proxy through the NAT device. After the NAT device intercepts the media code stream sent by the terminal B, the source address (that is, the local address of the terminal B, which is a private network address) and the source port. The number (that is, the local port number of the terminal B, which is the private network port number) is converted to obtain the public network address and the public network port number. After receiving the media code stream sent by the terminal B, the proxy records the converted public code. The mapping relationship between the network address, the public network port number, and the terminal B is also not forwarded for the media stream packet Proxy.

The proxy maps the public network address of the terminal A, the public network port number, the public network address of the terminal B, and the public network port number, and records the mapping.

After the process of receiving the media code stream by the proxy server shown in FIG. 6, the media capability renegotiation process shown in FIG. 7 is performed: In order to notify the other party of the public network address and the public network port number of the terminals A and B, the proxy initiates media capability renegotiation to the terminals A and B through the reinvite message.

At this point, the media capacity has been re-negotiated.

After the media capability re-negotiation between the terminal A and the terminal B is completed, the public network address and the public network port number of the peer end (media stream transmission and reception) are recorded, and the subsequent terminals A and B can directly send the media code stream to the peer public network. The address and the public network port number can be used to implement NAT media stream traversal, and no need to be forwarded by Proxy.

In order to make the objects, technical methods, and advantages of the present invention clearer, the present invention will be further described below in conjunction with the accompanying drawings and the embodiment of FIG. 2 (both terminals are in NAT).

Terminal A is located in a fully conical NAT. The local address, that is, the private network address is 10.1.1.2, the public network address mapped by NAT is 192.0.2.1 (the signaling address is the same as the media address); the local audio port is 10200, local video. The port is 10202.

Terminal B is located in a fully conical NAT. The local address, that is, the private network address is 10.0.0.3, and the public network address mapped by NAT is 192.0.2.3 (the signaling address is the same as the media address); the local audio port is 10000, local video. The port is 10002.

The proxy is located on the public network and the public network address is 192.0.2.2.

The process of NAT traversal based on SIP media capability renegotiation includes:

(1) The terminal A initiates an Invite call, and the SDP information carries the local media capability, where the c-line carries the local address of the terminal A, that is, the private network address is 10.1.1.2; the local audio port carried by the m-line is 10200, and the local video port is 10202, the related SDP is described as follows:

c=IN IP4 10.1.1.2

m=audio 10200 TP/AVP 9 8 0 m=video 10202 TP/AVP 109 34

(2) The Invite message reaches the Proxy through the NAT device. Since the media stream has not been established, the Proxy cannot obtain the public network sending and receiving address and port number corresponding to the media stream of the terminal A. In order to allow the media stream to pass the p _r0X y, the Proxy A new audio port 8510, a new video port 8512, is assigned to the terminal A, and the address in the c-line of the SDP information is replaced with the public network address of the Proxy. The SDP related description in the updated Invite message is as follows:

c=IN IP4 192.0.2.2

m=audio 8510 RTP/AVP 9 8 0

m=video 8512 RTP/AVP 109 34

(3) The Proxy forwards the Invite message to the terminal B, and the terminal B responds to the 200 OK message, where the SDP information carries the local media capability, where the c line carries the local address of the terminal B, that is, the private network address is 10.0.0.3, and the m line carries The local audio port is 10000 and the local video port is 10002. The related SDP is described as follows:

c=IN IP4 10.0.1.3

m=audio 10000 RTP/AVP 9 8 0

m=video 10002 RTP/AVP 109 34

(4) The Proxy receives the 200 OK message from the terminal B. Since the media stream has not been established, the proxy cannot obtain the public network sending and receiving address and port number corresponding to the media stream of the terminal B, in order to allow the media stream to pass the Proxy, Proxy. Similarly, terminal B is assigned a new audio port 9510, a new video port 9512, and the address in the c-line of the SDP information is replaced with the public network address of the Proxy. The SDP related description in the updated 200 OK message is as follows:

c=IN IP4 192.0.2.2

m=audio 9510 RTP/AVP 9 8 0

m=video 9512 RTP/AVP 109 34

(5) Terminal A receives the 200 OK message forwarded by the proxy, the media capability negotiation between the terminals A and B is completed, the terminal A returns an ACK message, the proxy forwards the ACK to the terminal B, and the call connection establishment is completed. At this point, the Proxy starts listening on the 9510, 9512 ports and receives the terminal. A media code stream; listening on port 8510, 8512, receiving media code stream from terminal B;

(6) After the call connection is established, terminal A sends the audio and video code streams to the address 192.0.2.2, port 9510, 9512 according to the description of SDP in the 200 OK message; and listens to 10200, 10202 at the local address 10.1.1.2. port.

The media code stream sent by the terminal A needs to pass through the NAT device to reach the proxy. After the NAT device intercepts the media code stream sent by the terminal A, the source address ( 10.1.1.2 ) and the source port number ( 10200 , 10202 ) are converted. The public network address is 192.0.2.1, and the public network port number is 38100 and 38102 respectively. After receiving the media code stream sent by terminal A, the proxy records the mapping relationship between the translated public network address, port number, and terminal A. The Proxy discards the first media stream packet and does not forward it.

(7) After the call connection is established, the terminal B sends the audio and video code streams to the address 192.0.2.2 according to the description of the SDP in the Invite message, and the port numbers are 8510 and 8512 respectively; and the local address 10.0.03 monitors 10000. , port 10002.

The media code stream sent by the terminal B needs to pass through the NAT device to reach the Proxy. After the NAT device intercepts the media code stream sent by the terminal B, the source address ( 10.0.1.3 ) and the source port number ( 10000 , 10002 ) are converted. The public network address is 192.0.2.3, and the public network port number is 39100 and 39102 respectively. After receiving the media code stream sent by the terminal B, the proxy records the mapping relationship between the converted public network address, the port number, and the terminal B. The code stream packet Proxy is also not forwarded.

(8) The public network address (publication and reception of the media stream) and the public network port number of the terminals A and B are collected through the steps (6) and (7), and the mapping relationship between the two is established.

The public network address corresponding to the terminal B recorded by the proxy is 192.0.2.3, and the public network port number is

39100, 39102, in order to notify the terminal A of the public network address and the public network port number (that is, the destination address and the destination port number of the terminal A to send the media stream), the proxy initiates media capability re-negotiation to the terminal A through the reinvite message, reinvite The relevant description of SDP in the message is as follows:

c=IN IP4 192.0.2.3

m=audio 39100 TP/AVP 9 8 0

m=video 39102 RTP/AVP 109 34 Similarly, the public network address of the terminal A recorded by the proxy is 192.0.2.1, and the public network port numbers are 38100 and 38102 respectively, in order to use the public network address and the public network port number (that is, the destination address of the terminal B to send the media stream) The destination port number is notified to the terminal B. The proxy initiates media capability re-negotiation to the terminal B through the reinvite message. The SDP related description in the reinvite message is as follows:

c=IN IP4 192.0.2.1

m=audio 38100 TP/AVP 9 8 0

m=video 38102 RTP/AVP 109 34

This completes the media capability renegotiation.

(9) Terminal A receives the reinvite message from the Proxy, stops sending the media stream to the Proxy (address 192.0.2.2, port number 9510, 9512), and starts to the public network address 192.0.2.3 corresponding to the terminal 8, the public network port number 39100. 39102 sends a media code stream; terminal B receives the reinvite message of the proxy, stops sending the media code stream to the proxy (address 192.0.2.2, port number 8510, 8512), and starts to the corresponding public network address 192.0.2.1 of terminal A, Port numbers 38100, 38102 send the media stream. At this point, terminal A and terminal B implement direct transmission of the media code stream, and no longer transit through the proxy.

The solution provided by the foregoing embodiment of the present invention can directly communicate between two terminal media through the Proxy under the premise of modifying the existing network device when the primary or the called party or one of the two parties is in the full cone NAT. It saves the cost of upgrading network equipment, reduces the delay of data transmission, reduces the load on the server, and improves efficiency.

In order to achieve the above technical solution, the embodiment of the present invention further provides a proxy server 10, which is located on the public network. As shown in FIG. 8, the proxy server includes:

The obtaining module 11 is configured to receive the media code streams from the first terminal and the second terminal, respectively, and obtain the public network address and the public network port number of the first terminal and the second terminal; and at least the first terminal and the second terminal One is located on the private network;

The media capability renegotiation module 12 is configured to initiate media capability renegotiation, and notify the obtained second terminal of the public address and the public network port number of the first terminal to the second terminal, and obtain the public network of the second terminal. The address and the public network port number are notified to the first terminal.

The proxy server further includes: a port assignment module 13 configured to allocate a port number to the first terminal and the second terminal respectively through the media capability negotiation process, and notify the second terminal of the port number assigned to the first terminal, which is to be The port number assigned by the second terminal is notified to the first terminal;

The monitoring module 14 is configured to listen to the port number assigned to the second terminal, and receive the media code stream from the first terminal; listen to the port number assigned to the first terminal, and receive the media code stream from the second terminal;

The obtaining module 11 is further configured to extract and record the public network address and the public network port number of the first terminal or the second terminal from the media code stream from the first terminal or the second terminal. Specifically: when the first terminal or the second terminal is located in the private network, the public network address and the public network port number of the first terminal or the second terminal are converted by the corresponding private network address and the private network port number, specifically: When the NAT device intercepts the media stream sent by the first terminal or the second terminal to the proxy server, the source address and the source port number (that is, the private network address and the private network port number) are converted into the public network address and the public network. Port number; The source address and source port number of the corresponding media stream are the public network address and the public network port number of the first terminal or the second terminal when the first terminal or the second terminal is located on the public network.

The interaction module 15 is configured to receive the request message from the first terminal, notify the port assignment module 13 to assign a port number to the first terminal, and forward the request message to the second terminal; the request message forwarded to the second terminal carries the proxy server a public network address and a port number assigned to the first terminal; configured to receive a response message from the second terminal, notify the port assignment module 13 to assign a port number to the second terminal, and forward the response message to the first terminal; The response message to the first terminal carries the public network address of the proxy server and the port number assigned to the second terminal.

The mapping module 16 is configured to establish a mapping relationship between the public network address of the first terminal, the public network port number, the public network address of the second terminal, and the public network port number.

The media capability renegotiation module 12 is further configured to initiate media capability re-negotiation to the first terminal and the second terminal by using the request message respectively; the request message sent to the first terminal carries the public network address and the public network port number of the second terminal The request message sent to the second terminal carries the first terminal Public network address and public network port number.

In the specific implementation process, the foregoing obtaining module 11, the media capability renegotiation module 12, the port allocating module 13, the listening module 14, and the interaction module 15 may be implemented by a chip having a communication and processing function in the proxy server, and the mapping module 16 may be configured by The central processing unit (CPU) of the proxy server, the processor (MPU, Micro Processing Unit) or the digital signal processor (DSP) is implemented.

As shown in FIG. 9, the embodiment of the present invention further provides a NAT traversal system based on SIP media capability re-negotiation, including the proxy server 10, the first terminal 20, and the second terminal 30 shown in FIG. 8, wherein:

The proxy server 10 is configured to obtain the public network address and the public network port number of the first terminal 20 and the second terminal 30. The public network address and the public network port of the first terminal 20 to be obtained are also configured to initiate the media capability renegotiation. The notification is sent to the second terminal 30, and the obtained public address of the second terminal 30 and the public network port number are notified to the first terminal 20;

The first terminal 20 is configured to send a media stream to the public network address and the public network port number of the second terminal 30;

The second terminal 30 is configured to send the media code stream to the public network address and the public network port number of the first terminal 20.

The embodiment of the present invention further provides a NAT traversal device based on SIP media capability renegotiation, which includes a hardware processing server, configured to respectively receive media code streams from the first terminal and the second terminal, and acquire the first terminal and the second terminal. The public network address and the public network port number of the terminal are also configured to initiate the media capability renegotiation, and notify the obtained second terminal of the public network address and the public network port number of the first terminal, and obtain the public network of the second terminal. The address and the public network port number are notified to the first terminal.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Industrial applicability

The SIP traversal method, the proxy server and the system based on the SIP media capability renegotiation of the present invention enable the first terminal and the second terminal to directly communicate based on the public network address of the other party and the public network port number, without forwarding by the proxy server; The implementation of the above technical solution is based on the existing network architecture, no need to improve it, and no need to set up a special traversing server to realize direct communication between terminals, thereby saving cost.

Claims

claims

1. A NAT traversal method based on SIP media capability renegotiation. At least one of the first terminal and the second terminal is located in the private network, and the proxy server is located in the public network. The method includes:

The proxy server receives the media code stream from the first terminal and the second terminal respectively, and obtains the public network address and public network port number of the first terminal and the second terminal;

The proxy server initiates media capability renegotiation, notifies the second terminal of the obtained public network address and public network port number of the first terminal, and transmits the obtained public network address and public network port number of the second terminal to the second terminal. The port number is notified to the first terminal.

2. The NAT traversal method based on SIP media capability renegotiation according to claim 1, wherein the proxy server receives media code streams from the first terminal and the second terminal respectively, and obtains the media code streams from the first terminal and the second terminal. The terminal’s public network address and public network port number, including:

During the media capability negotiation process, the proxy server allocates port numbers to the first terminal and the second terminal respectively, and notifies the second terminal of the port number allocated to the first terminal, and provides the Notify the first terminal of the port number assigned by the second terminal;

The proxy server listens on the port number assigned to the second terminal and receives the media code stream from the first terminal; the proxy server listens on the port number assigned to the first terminal and receives the media code stream from the second terminal. The media code stream of the terminal;

The proxy server extracts and records the public network address and public network port number of the first terminal or the second terminal from the media code stream from the first terminal or the second terminal.

3. The NAT traversal method based on SIP media capability renegotiation according to claim 2, wherein during the media capability negotiation process, the proxy server allocates port numbers to the first terminal and the second terminal respectively, and assigns port numbers to the first terminal and the second terminal. Notifying the second terminal of the port number assigned by the first terminal, and notifying the first terminal of the port number assigned to the second terminal, including: the proxy server receiving a request message from the first terminal. , allocate a port number to the first terminal, and forward the request message to the second terminal; The request message from the second terminal carries the public network address of the proxy server and the port number assigned to the first terminal;

The proxy server receives the response message from the second terminal, allocates a port number to the second terminal, and forwards the response message to the first terminal; the response forwarded to the first terminal The message carries the public network address of the proxy server and the port number assigned to the second terminal.

4. The NAT traversal method based on SIP media capability renegotiation according to claim 2, wherein the proxy server extracts and records the first terminal's media code stream from the first terminal or the second terminal. Or the public network address and public network port number of the second terminal are:

When the first terminal or the second terminal is located in a private network, the public network address and public network port number obtained by converting the private network address and private network port number of the first terminal or the second terminal;

When the first terminal or the second terminal is located on the public network, the corresponding source address and source port number of the media code stream are the public network address and public network port number of the first terminal or the second terminal.

5. The NAT traversal method based on SIP media capability renegotiation according to claim 1 or 4, wherein, after the proxy server obtains the public network address and public network port number of the first terminal and the second terminal; The method further includes: the proxy server establishing a mapping relationship between the public network address and public network port number of the first terminal and the public network address and public network port number of the second terminal.

6. The NAT traversal method based on SIP media capability renegotiation according to claim 1, wherein the proxy server initiates media capability renegotiation to the first terminal and the second terminal respectively through a request message;

The request message sent to the first terminal carries the public network address and public network port number of the second terminal; the request message sent to the second terminal carries the public network address of the first terminal. network address and public network port number.

7. A proxy server, the proxy server is located on the public network, including:

The acquisition module is configured to receive media code streams from the first terminal and the second terminal respectively, and obtain the public network address and public network port number of the first terminal and the second terminal; at least one of the first terminal and the second terminal is located in a private network;

The media capability renegotiation module is configured to initiate media capability renegotiation, notify the second terminal of the obtained public network address and public network port number of the first terminal, and provide the obtained public network address and public network port number of the second terminal. The address and public network port number are notified to the first terminal.

8. The proxy server according to claim 7, further comprising:

The port allocation module is configured to allocate port numbers to the first terminal and the second terminal respectively through the media capability negotiation process, and notify the second terminal of the port number allocated to the first terminal, and provide the port number for the first terminal. Notify the first terminal of the port number assigned by the second terminal; a monitoring module configured to listen at the port number assigned to the second terminal and receive the media code stream from the first terminal; The port number assigned by the first terminal monitors and receives the media code stream from the second terminal;

The acquisition module is further configured to extract and record the public network address and public network port number of the first terminal or the second terminal from the media code stream from the first terminal or the second terminal.

9. The proxy server according to claim 8, further comprising:

The interaction module is configured to receive a request message from the first terminal, notify the port allocation module that the first terminal allocates a port number, and forward the request message to the second terminal; The request message from the second terminal carries the public network address of the proxy server and the port number allocated to the first terminal; it is also configured to receive a response message from the second terminal and notify the port allocation module to The second terminal allocates a port number and forwards the response message to the first terminal; the response message forwarded to the first terminal carries the public network address of the proxy server and the The assigned port number.

10. The proxy server according to claim 7, further comprising:

The mapping module is configured to establish a mapping relationship between the public network address and public network port number of the first terminal and the public network address and public network port number of the second terminal.

11. The proxy server according to claim 7, wherein, The media capability renegotiation module is further configured to initiate media capability renegotiation to the first terminal and the second terminal respectively through a request message; the request message sent to the first terminal carries the second terminal The public network address and public network port number; The request message sent to the second terminal carries the public network address and public network port number of the first terminal.

12. A NAT traversal system based on SIP media capability renegotiation, including the proxy server according to any one of claims 7 to 10, a first terminal and a second terminal, wherein:

The proxy server is configured to receive media code streams from the first terminal and the second terminal respectively, and obtain the public network addresses and public network port numbers of the first terminal and the second terminal; and is also configured to initiate a media capability reset. Negotiate, notify the second terminal of the obtained public network address and public network port number of the first terminal, and notify the obtained first terminal of the public network address and public network port number of the second terminal. terminal;

The first terminal is configured to send a media code stream to the public network address and public network port number of the second terminal;

The second terminal is configured to send a media code stream to the public network address and public network port number of the first terminal.

13. A NAT traversal device based on SIP media capability renegotiation. The device includes a hardware processing server, wherein:

The hardware processing server is configured to receive media code streams from the first terminal and the second terminal respectively, and obtain the public network addresses and public network port numbers of the first terminal and the second terminal; and is also configured to initiate media capabilities. Re-negotiate, notify the second terminal of the obtained public network address and public network port number of the first terminal, and notify the obtained public network address and public network port number of the second terminal to the third terminal. a terminal.