WO2006015525A1

WO2006015525A1 - A method for point-to-point calling between two multimedia terminals in the private network

Info

Publication number: WO2006015525A1
Application number: PCT/CN2005/000205
Authority: WO
Inventors: Jiazhou Li; Jia Cao; Yawei Chai; Ziming Jin; Chenggang Liu
Original assignee: Zte Corporation
Priority date: 2004-08-13
Filing date: 2005-02-22
Publication date: 2006-02-16
Also published as: CN1735055A; GB0702877D0; CN100401700C; GB2432078B; GB2432078A

Abstract

Providing a method for point-to-point calling between two multimedia terminals in the private network, by adding a multimedia gateway device to the public network, point-to-point calling between private terminals is replaced with calling the multimedia gateway, then establishes H.245 channel of H.323 protocol to the private terminals respectively by the multimedia gateway device, then performing capability alternation, principal and subordinate determination, and establishing of logic channel, at last transmits the information of the two private terminals by the multimedia gateway device thereby it is achieved that point-to-point calling between two multimedia terminals in the private network. The whole process of transferring is lucidity for users according to the method ~f this invention, it is unnecessary for users to know any information of the network structure, so it is convenient and simple; the method provided by this invention is capable of supporting any NAT type.

Description

Method for point-to-point call of multimedia terminal in two private networks

The present invention relates to multimedia communication, and more particularly to a point-to-point calling method for a multimedia terminal in two private networks based on the H.323 protocol. Background technique

With the rapid development of IP network broadband services in recent years, the packet-based multimedia communication system standard H.323 (which is a packet network multimedia communication standard developed by the International Telecommunication Union) is widely used in video conferencing and IP telephony. Since many users access the public network through NAT (Network Address Translation, see IETF RFC3489), the private IP address is used internally. The access to the public network is usually translated by NAT. The H.323 protocol itself does not consider the application of NAT. Its address embedding feature conflicts with the NAT device, which creates the problem of interworking between the internal and external networks. How to realize the interworking of multimedia terminals (hereinafter referred to as H.323 terminals) in two private networks is an urgent problem that the industry needs to solve. There are two main solutions to this problem:

1. Using the MCU on the public network to hold a conference, the MCU holds a conference in which two terminals need to communicate to realize communication between the two terminals. Although such a method can realize interworking between the two terminals, the following Defects: (1) Requires the user to reserve a meeting, and the operation is complicated. (2) In the case where there is no private network, the user can implement the call port H by directly calling the name of the other terminal. Only when the calling and called users are in the private network, the conference needs to be initiated to realize the communication between the two parties. You need to be familiar with the network environment to operate correctly, and the operability is poor. (3), point-to-point calls cannot be made directly between the two terminals.

2. "STUN - Simple Traversal of User Datagram Protocol (UDP) Through Network Address Translators (NATs)" (IETF RFC3489) proposes a UDP traversal

The NAT method, but the solution has the following drawbacks: (1) The protocol only supports NAT traversal in UDP mode, and does not provide TCP traversal mode. (2) At the same time, the UDP traversal method does not support symmetric type NAT. Invention disclosure The technical problem to be solved by the present invention is to propose a method for point-to-point calling of multimedia terminals in two private networks, and to solve the problem that when the H.323 terminals in two private networks communicate, the calling process cannot traverse the NAT devices of the two private networks. And the problem of interoperability.

To achieve the above object, the present invention provides a method for point-to-point calling of a multimedia terminal in two private networks, which is characterized in that it comprises the following steps:

Step 1: Add a multimedia gateway on the public network to implement signaling and media switching between the private network terminals;

Step 2: For the call between the two private network terminals, the H.245 channel of the H.323 protocol is established with the two private network terminals through the multimedia gateway, and the capability interaction, the master-slave decision, and the establishment of the logical channel are performed. The point-to-point call between the two private network terminals is transferred to the pair of multimedia gateways, and the two private network terminals are matched by the multimedia gateway into a pair of calls;

Step 3: The multimedia gateway forwards information between the two private network terminals, thereby implementing point-to-point calls of the multimedia terminals in the two private networks.

The method for point-to-point calling of the multimedia terminal in the two private networks is characterized in that, before the second step, the method further includes: recording the multimedia terminal and the multimedia gateway in the two private networks on the gatekeeper of the public network, The gatekeeper implements management of the terminal and performs terminal type judgment.

The method for point-to-point calling of the multimedia terminal in the two private networks is characterized in that the registration process includes the following steps:

Step 201: The private network terminals A and B respectively send a registration request to the gatekeeper, and the gatekeeper responds to the registration message confirmation, and determines that the terminal type is a private network terminal according to the IP address in the registration message and the routing address of the message header;

Step 202: The multimedia gateway sends a registration request to the gatekeeper, and the gatekeeper responds to the registration message to confirm that the registered endpoint type is a multimedia gateway.

The method for the point-to-point call of the multimedia terminal in the two private networks is characterized in that the process of managing the terminal and determining the type of the terminal by the gatekeeper includes the following steps:

The gatekeeper receives the call request message in an idle state;

Determining whether the call request is sent by the multimedia gateway;

If the call request is sent by the multimedia gateway, further determine whether the called party is a private network terminal; if the called party is a private network terminal, hang up the calling party, notify the called terminal to call the multimedia gateway + the calling terminal; and then return to Idle state; if the called party is not a private network terminal, it responds to the called terminal's call Return to the idle state after the address;

If the call request is not sent by the multimedia gateway, it is determined whether the called party or the calling endpoint has a private network terminal; if not, the called terminal's call address is returned to the idle state; if the called party or the calling endpoint is private The network terminal then determines whether there is a registered multimedia gateway; if yes, it responds to the multimedia gateway's call address and then returns to the idle state; if there is no registered multimedia gateway, the call is rejected and returned to the idle state.

The method for the point-to-point call of the multimedia terminal in the two private networks is characterized in that the step 2 includes the following steps:

Step 301: The private network terminal A initiates a call request to the private network terminal B to the gatekeeper.

Step 302: After the gatekeeper determines that the called terminal is a private network terminal, returns the call address of the multimedia gateway to the private network terminal A;

Step 303: The private network terminal A initiates a call connection to the multimedia gateway, and the called name is still the private network terminal B;

Step 304: After receiving the call connection of the private network terminal A, the multimedia gateway initiates a call request to the terminal B to the gatekeeper. The calling name includes the multimedia gateway name information and the private network terminal A information. Step 305, the gatekeeper determines the calling party. After the multimedia gateway is called a private network terminal, the multimedia gateway hangs up the call to the terminal B;

Step 306, the gatekeeper uses the private network terminal B to notify the gatekeeper to register the channel to initiate the call to the multimedia gateway, and the call name is the multimedia gateway + the private network terminal A;

Step 307: The private network terminal B confirms to the gatekeeper response message, and initiates a call request to the multimedia gateway + private network terminal A to the gatekeeper;

Step 308, the gatekeeper returns the call address of the multimedia gateway to the private network terminal B.

Step 309, the private network terminal B initiates a call connection to the multimedia gateway, and the called name is a multimedia gateway + a private network terminal A;

Step 310: The multimedia gateway matches the call connection between the private network terminal A and the private network terminal B as a pair of calls;

Step 311: The private network terminal A and the private network terminal B respectively establish an H.245 channel of the H.323 protocol with the multimedia gateway, and perform capability interaction, master-slave determination, and establishment of a logical channel. BRIEF DESCRIPTION OF THE DRAWINGS 1 is a schematic diagram of an application network topology structure of a method proposed by the present invention;

2 is a signaling flow chart of a point-to-point call of a multimedia terminal in two private networks proposed by the present invention; FIG. 3 is a state diagram of a judgment policy when a gatekeeper receives a call request. The best way to implement the invention

The various implementation steps of the present invention are further described below in conjunction with the accompanying drawings.

FIG. 1 is a schematic diagram of an application network topology structure of the method proposed by the present invention. The implementation of the present invention mainly relates to the following devices: H.323 terminal, NAT device, multimedia gateway, gatekeeper. As shown in Figure 1, terminal A and terminal B are on different private networks. Terminal A and terminal B and public network communication need to pass through the NAT device to translate the private network address of the terminal information into a public network address. The gatekeeper of the public network implements the management of the terminal, and the multimedia gateway implements signaling and media switching between the private network terminals.

2 is a signaling flow chart of a point-to-point call of a multimedia terminal in two private networks proposed by the present invention. As shown in FIG. 2, the signaling process of the method proposed by the present invention is as follows:

1. Private network terminal A sends a registration request to the gatekeeper.

2. The gatekeeper responds to the registration message with the private network terminal A. The gatekeeper knows that the terminal A is a NAT terminal according to the IP address in the registration message of the terminal A and the routing address of the message header.

3. The private network terminal B sends a registration request to the gatekeeper.

4. The gatekeeper responds to the registration message with the private network terminal B. The gatekeeper knows that the terminal B is the terminal after the NAT according to the IP address in the registration message of the private network terminal B and the routing address of the message header.

5. The multimedia gateway sends a registration request to the gatekeeper.

6. After receiving the registration message of the multimedia gateway, the gatekeeper responds to the multimedia gateway to confirm the registration message. The registered endpoint type is a multimedia gateway.

7. The private network terminal A initiates a call request to the private network terminal B to the gatekeeper.

8. The gatekeeper finds that the called terminal B is a terminal after the NAT, and uses the multimedia gateway to transfer the intercommunication between the calling and called terminals, and the address sent back to the private network terminal A is the address of the multimedia gateway.

9. The private network terminal A initiates a call connection to the multimedia gateway, and the called name is still terminal B.

10. After receiving the call connection of the private network terminal A, the multimedia gateway knows that the called multimedia gateway sends a call request to the terminal B to the gatekeeper according to the call information of the terminal A, and the calling name includes the multimedia gateway name information and Terminal A information, for example, using the multimedia gateway + terminal A name. 11. The gatekeeper finds that the called terminal B is a private network terminal, and the calling party is a multimedia gateway. Therefore, the multimedia gateway hangs up the call to the terminal B. If the called party is a public network terminal, the gatekeeper directly responds to the address of the terminal, and the multimedia gateway directly calls the terminal.

12. The gatekeeper uses the private network terminal B to notify the private network terminal B of the channel registered by the gatekeeper to initiate a call to the multimedia gateway, and the call name is multimedia gateway + terminal A. See the non-standard message extension for message definitions.

13. The private network terminal B confirms the response message to the gatekeeper. See the non-standard message extension for message definitions.

14. The private network terminal B initiates a call request to the multimedia gateway + terminal A to the gatekeeper.

15. The gatekeeper responds to the address of the multimedia gateway.

16. The private network terminal B initiates a call connection to the multimedia gateway. The multimedia gateway is called the multimedia gateway + terminal A according to the call of the private network terminal B, so the private network terminal B and the private network terminal A are matched into a pair of calls.

17. The H.245 channel of the H.323 protocol is established between the private network terminal A and the multimedia gateway, and capability interaction, master-slave decision, and logical channel establishment are performed.

18. The H.245 channel of the H.323 protocol is established between the multimedia gateway and the private network terminal B, and the capability interaction, the master-slave decision, and the establishment of the logical channel are performed. 19. The multimedia gateway forwards information between the private network terminal A and the private network terminal B.

The non-standard message extension mentioned above is as follows - NSMsNonStandardData:: = SEQUENCE

{

commandType NatNSMCommand, — the way the command is

Calling AliasAddress OPTIONAL, — caller alias

} NatNSMCommand ::= CHOICE

{

inviteRequest NULL, --activation request

inviteReply NULL, --Activate the answer

} FIG. 3 is a state diagram of a judgment policy when the gatekeeper receives a call request. The received call request of the gatekeeper includes:

1. The multimedia gateway sends a call request: (1) calling the private network terminal; (2) calling the public network terminal.

2. The terminal issues a call request: (1) The calling party and the called terminal have one in the private network; (2) The calling party The called terminal is on the public network.

As shown in FIG. 3, the gatekeeper receives the call request message in the idle state, first determines whether the call request is sent by the multimedia gateway; if yes, further determines whether the called party is a private network terminal; if the called party is a private network terminal, hangs up The calling party notifies the called terminal to call the multimedia gateway + the calling terminal; then returns to the idle state; if the called party is not the private network terminal, it responds to the called terminal's calling address and then returns to the idle state.

The invention may, of course, be embodied in a variety of other embodiments without departing from the spirit and scope of the invention. Changes and modifications are intended to be included within the scope of the appended claims. Industrial applicability

The technical solution proposed by the present invention realizes the interworking of two terminals by adding a multimedia gateway device in the public network and transferring the calls of the terminals in the two private networks. For the user, the entire transfer process is transparent, and the user is transparent. It is not necessary to know the information of any network structure, and it is convenient and simple to use; the method proposed by the present invention can support any NAT type. The method proposed by the invention adopts: 1. Solving the point-to-point call problem of the private network H.323 terminal, and the user can no longer care about the network environment in which the user is located, and can perform a point-to-point call between two points. 2, easy to maintain. Through the multimedia gateway device, the network environment problem on the user side is centralized to the central office device for solution, which is convenient for deployment, management, maintenance, and upgrade. 3. The interoperability of the system is improved. By deploying the multimedia gateway device, the call problem of the post-NAT user terminal of different systems can be converted into the interworking of the central office gateway, and the multimedia gateway is generally deployed on the public network, thereby eliminating the H.323 traversing NAT problem.

Claims

Claim

A method for point-to-point calling of a multimedia terminal in two private networks, characterized in that the method comprises the following steps:

Step 2: For the call between the two private network terminals, the H.245 channel of the H.323 protocol is established with the two private network terminals by the multimedia gateway, and the capability interaction, the master-slave decision, and the logical channel are performed. Establishing, transferring a point-to-point call between two private network terminals into a call to the multimedia gateway, and the multimedia gateway matches the two private network terminals as a pair of calls;

2. The method for point-to-point calling of a multimedia terminal in two private networks according to claim 1, further comprising the step of: step 2: placing the multimedia terminal and the multimedia gateway in the two private networks on the public network The gatekeeper performs registration, and the gatekeeper implements management of the terminal to perform terminal type judgment.

3. The method for point-to-point calling of a multimedia terminal in two private networks according to claim 2, wherein the registration process comprises the following steps:

Step 201: The private network terminal A and the private network terminal B respectively send a registration request to the gatekeeper, and the gatekeeper responds to the registration message to confirm, and determines that the terminal type is a private network terminal according to the IP address in the registration message and the routing address of the message header. ;

The method for the point-to-point call of the multimedia terminal in the two private networks according to claim 3, wherein the process of managing the terminal and determining the type of the terminal by the gatekeeper comprises the following steps: The gatekeeper receives the idle state. To call request message;

Determining whether the call request is sent by the multimedia gateway;

The method of claim 2, wherein the step 2 includes the following steps:

Step 302: After the gatekeeper determines that the called terminal is a private network terminal, returns the calling address of the multimedia gateway to the private network terminal A.

Step 309: The private network terminal B initiates a call connection to the multimedia gateway, and the called name is a multimedia gateway + a private network terminal A;

Step 311: The private network terminal A and the private network terminal B respectively establish an H.245 channel of the H.323 protocol with the multimedia gateway, and perform capability interaction, master-slave determination, and establishment of a logical channel.