CN1299476C - Method for H.323 agent server to register on gatekeeper from terminals after being agent of NAT - Google Patents

Abstract

The invention discloses a method for a H.323 proxy server to register a terminal with a gatekeeper after NAT. The server dynamically assigns listening ports to different terminal registrations during terminal registration, and uses (same IP address + different ports) to identify different terminals, so that different private network terminals pass the registration addresses sent by the same H.323 proxy server are not the same, so for different types of gatekeepers, correct registration can be performed. Using the method proposed by the invention, when the H.323 proxy server behind the NAT registers with the gatekeeper, it can be well compatible with different types of gatekeepers, which improves the interconnection and interoperability of the system.

Description

A method for H.323 proxy server to register a terminal after network address translation with a gatekeeper

technical field

The invention relates to multimedia communication, in particular to a registration method of a multimedia terminal based on the H.323 protocol (a packet network multimedia communication standard formulated by the International Telecommunication Union).

Background technique

With the vigorous development of IP network broadband services in recent years, the group-based multimedia communication system standard H.323 is widely used in video conferencing and IP telephony. Since many enterprises and units have built their own local area networks and use private IP addresses internally, access to the public network generally uses NAT equipment for address translation. However, the H.323 protocol itself does not consider the application of NAT (Network Address Translation, which is divided into static NAT, dynamic NAT and PAT). , The problem of intercommunication with the external network.

Currently, there are many methods to realize the traversal of this kind of NAT device, and adopting H.323 proxy server is a relatively thorough way to solve this problem. The implementation method of using the H.323 proxy server is: put the H.323 proxy server in the private network, and perform static NAT on the H.323 proxy server on the NAT device (the private network address and the public network address are one-to-one conversion, allowing the public network to access the internal network), so that the external network can be accessed, and then the terminal on the internal network designates the proxy server as a gatekeeper (a device that provides services such as address resolution and bandwidth management for H.323 endpoints) to the The H.323 proxy server sends a registration request, and the H.323 proxy server acts as a terminal to register with the public network gatekeeper. Because the H.323 proxy server modifies the IP address in the H.323 protocol in advance to the H.323 proxy server in the NAT The public network address of the static NAT performed on the device, and the terminal IP address obtained by the gatekeeper is the public network address of the H.323 proxy server.

FIG. 1 is a schematic diagram of a network topology using an H.323 proxy server. As shown in Figure 1, the private network terminal 1 and the private network terminal 2 in the private network are both connected to the H.323 proxy server, the H.323 proxy server is connected to the NAT device, and the NAT device is connected to the gatekeeper in the public network. There are mainly two ways to register with the gatekeeper using the H.323 proxy server:

1. A private protocol is adopted between the H.323 proxy server and the gatekeeper. When the H.323 proxy server receives a terminal registration message and registers with the gatekeeper, the registration message contains non-standard messages, and the gatekeeper knows the registration message according to the non-standard message It is sent through the H.323 proxy server, and then the gatekeeper records the information of the terminal sent by the H.323 proxy server. If a terminal calls the terminal through the H.323 proxy server, the gatekeeper will direct it to the H.323 proxy server superior.

2. After the H.323 proxy server receives the private network terminal registration request, it modifies the registration address in the registration message to the address of the H.323 proxy server, and registers with the gatekeeper of the public network.

The first way is that the H.323 terminal registration message contains non-standard messages, and non-standard messages need to be supported between the gatekeeper and the H.323 proxy server. The disadvantage of this method is obvious: there are differences with other manufacturers. Gatekeeper interconnection issues.

The second method uses the H.323 standard protocol, and the forwarded terminal registration request uses the public network call address (IP address + port) of the H.323 proxy server, but this registration method causes such a phenomenon that all The registration information of the same H.323 proxy server registered to the public network gatekeeper corresponds to the same address, so the gatekeeper must support such a situation, that is, the gatekeeper only checks the registered terminal alias (terminal name). Add a new registration information to the alias, so that different terminal aliases on the gatekeeper correspond to the same address (IP address and port), but in the actual application system, when some types of gatekeepers receive the registration information, they are Need to check the registration address, if the registration address is the same, then the gatekeeper will consider it as the same terminal, and the gatekeeper will overwrite the original registration record with the newly received registration information record, that is, some types of gatekeepers do not support multiple The terminals correspond to the same registered address. This is also a problem in the practical application of the second method.

Contents of the invention

The present invention is in order to overcome the incompatibility problem with different types of gatekeepers when the H.323 proxy server behind NAT registers with the gatekeeper in the prior art, and proposes a H.323 proxy server proxy NAT terminal to the gatekeeper method of registration.

The purpose of the present invention is to improve the interoperability between the H.323 proxy server and the gatekeeper, so the messages between the H.323 proxy server and the gatekeeper all adopt the H.323 standard protocol, and non-standard messages are not used. The core idea of the present invention is: in the H.323 protocol, the registration address of the private network terminal is expressed in the form of (IP address+port), and the proxy server dynamically allocates the listening port to different terminal registrations when the terminal is registered. Use (same IP address + different port) to identify different terminals, so that the registration addresses sent by different terminals through the same H.323 proxy server are different, and the intercommunication performance with different gatekeepers is enhanced.

A kind of H.323 proxy server proxy NAT back terminal registers the method with gatekeeper, comprises the following steps:

The first step is to define a port pool according to the number of private network terminals to be proxied by the H.323 proxy server;

The second step is to do static NAT of the H.323 proxy server on the NAT device, open the port pool defined in the first step, and allow terminals outside the NAT device to access the port listened to by the H.323 proxy server;

The third step, the port pool defined in the first step is set on the H.323 proxy server, and the H.323 proxy server is started;

Step 4, the private network terminal designates the gatekeeper as the proxy server, and sends a registration request to the H.323 proxy server;

Step 5: After the H.323 proxy server receives the registration request from the private network terminal, it judges whether the terminal is registering for the first time; listen on;

The 6th step, the H.323 proxy server revises the registration request message received, and the registration address is modified to the public network address behind the static NAT of the H.323 proxy server and the port that the terminal listens to on the H.323 proxy server, and then Send a registration message to the gatekeeper;

Step 7: After receiving the registration request from the H.323 proxy server, the gatekeeper performs authentication. If the authentication is passed, if it is found that the private network terminal is registered for the first time, add the registration information of the terminal. If it is found that the private network terminal has already registered If passed, update the registration record of the private network terminal; if the authentication fails, go to step 9;

Step 8, the gatekeeper sends a confirmation message to the H.323 proxy server, and the H.323 proxy server records the private network terminal information after receiving the confirmation message, and sends a confirmation message to the private network terminal, and the registration ends;

The ninth step, the gatekeeper sends a rejection message to the H.323 proxy server, and the H.323 proxy server releases the listening port allocated for the private network terminal in the fifth step after receiving the rejection message, and sends a rejection message to the private network terminal message, the registration is over.

The number of ports in the port pool in the first step above is equal to the number of private network terminals to be proxied by the H.323 proxy server.

In the above fourth step, the registration address in the registration request sent by the private network terminal to the H.323 proxy server is the private network address of the terminal and a listening port on the terminal.

The above method also includes the step of canceling the registration of the private network terminal:

Step 1, the private network terminal sends a message to cancel the registration to the H.323 proxy server;

Step 2, the H.323 proxy server releases the listening port allocated for the terminal after receiving the message, and then sends a message to cancel the registration to the gatekeeper;

Step 3, after the gatekeeper receives the deregistration message of the H.323 proxy server, it sends a deregistration confirmation to the H.323 proxy server;

Step 4: After receiving the cancellation confirmation from the gatekeeper, the H.323 proxy server forwards the message to the private network terminal, and the cancellation of registration is completed.

The above method also includes the step of the gatekeeper canceling the registration of the private network terminal:

Step A, gatekeeper send the message of canceling registration to H.323 proxy server;

Step B, the H.323 proxy server releases the listening port allocated for the canceled registration terminal after receiving the message, and then sends a message to cancel the registration to the private network terminal;

Step C, after receiving the deregistration message from the H.323 proxy server, the private network terminal sends a deregistration confirmation to the H.323 proxy server;

In step D, the H.323 proxy server forwards the message to the gatekeeper after receiving the cancellation confirmation of the private network terminal, and the gatekeeper cancels the registration of the private network terminal.

The technical solution proposed by the present invention establishes a listening port pool (a section of port address) and uses (same IP address + different ports) to identify different private network terminals, so that different private network terminals pass through the same H. The registration addresses sent by the 323 proxy server are different, so the correct registration can be performed for different types of gatekeepers. Using the method proposed by the invention, when the H.323 proxy server behind the NAT registers with the gatekeeper, it can be well compatible with different types of gatekeepers, which improves the interconnection and interoperability of the system.

Description of drawings

Fig. 1 is a schematic diagram of a network topology using an H.323 proxy server;

Fig. 2 is a flowchart of the registration method proposed by the present invention;

Fig. 3 is a flow chart of canceling registration of a private network terminal;

Fig. 4 is a flow chart of the gatekeeper canceling the registration of the private network terminal.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

FIG. 1 has already been explained in the background art.

Fig. 2 is a flow chart of the registration method proposed by the present invention. The main process of the method proposed by the present invention is: the H.323 proxy server first sets up a listening port pool (a section of port address), and after the H.323 proxy server receives the registration request of the private network terminal, it takes out a listening port pool. Listen to the port, change the registration address of the terminal registration request to the public network IP address of the H.323 proxy server and the port that the terminal listens to, and then register with the gatekeeper. If the gatekeeper fails to register or the terminal cancels registration, H.323 The proxy server releases the listening port of the terminal for use when other terminals register.

Specifically include the following steps:

The first step, according to the number of the private network terminal that H.323 proxy server will act as agent, define a port pool; In one embodiment of the present invention, the number of ports in the port pool and the private network that H.323 proxy server will act The number of terminals is equal. The second step is to do the static NAT of the H.323 proxy server on the NAT device, open the port pool defined in the first step, and allow the terminal outside the NAT device to access the port listened to by the H.323 proxy server; the third step is to The port pool defined in the first step is set on the H.323 proxy server, and the H.323 proxy server is started; the fourth step, the private network terminal designates the gatekeeper as the proxy server, and sends a registration request to the H.323 proxy server, and the registration address is The private network address of the terminal and a listening port on the terminal. Step 5: After the H.323 proxy server receives the registration request from the private network terminal, it judges whether the terminal is registering for the first time; Listen on the Internet; the sixth step, the H.323 proxy server revises the received registration request message, and the registration address is modified to the public network address behind the static NAT of the H.323 proxy server and the terminal listens on the H.323 proxy server port, and then send a registration message to the gatekeeper; step 7, the gatekeeper will perform authentication after receiving the registration request from the H.323 proxy server. Registration information, if it is found that this private network terminal has been registered, update the registration record of this private network terminal; if the authentication fails, then go to the ninth step; the eighth step, the gatekeeper sends a confirmation message to the H.323 proxy server, The H.323 proxy server records the private network terminal information after receiving the confirmation message, and sends a confirmation message to the private network terminal, and the registration ends; the ninth step, the gatekeeper sends a rejection message to the H.323 proxy server, and the H.323 proxy After receiving the rejection message, the server releases the listening port allocated for the private network terminal in the fifth step, and sends a rejection message to the private network terminal, and the registration ends.

Fig. 3 is a flowchart of a private network terminal canceling registration. As shown in Figure 3, the step that private network terminal cancels registration comprises: Step 1, private network terminal sends the message of canceling registration to H.323 proxy server; Step 2, H.323 proxy server releases as this The listening port that terminal distributes, then sends the message that cancels registration to gatekeeper; After step 3, gatekeeper receives the cancellation registration message of H.323 proxy server, sends cancellation registration confirmation to H.323 proxy server; Step 4, H .323 After receiving the cancellation confirmation from the gatekeeper, the proxy server forwards the message to the private network terminal, and the cancellation of registration is completed.

Fig. 4 is a flow chart of the gatekeeper canceling the registration of the private network terminal. As shown in Figure 4, the step that gatekeeper cancels private network terminal registration comprises: step A, gatekeeper send the message that cancels registration to H.323 proxy server; Step B, H.323 proxy server are released after receiving this message as The listening port allocated by the canceled registration terminal sends a message of canceling registration to the private network terminal; after step C, the private network terminal receives the cancellation registration message of the H.323 proxy server, it sends a cancellation message to the H.323 proxy server Confirmation of registration: step D, after the H.323 proxy server receives the cancellation confirmation of the private network terminal, it forwards the message to the gatekeeper, and the gatekeeper cancels the registration of the private network terminal.

Claims (5)

1. the process registration to the gatekeeper of the terminal after the acting server agency network address transition H.323 is characterized in that comprising the following steps:

The number of the first step, the private net terminal that will act on behalf of according to acting server H.323 defines a port pool;

Second step, do the static network address conversion of acting server H.323 on network address translation apparatus, the port pool that defines in the open first step allows the H.323 acting server port of intercepting of the outer terminal access of network address translation apparatus;

The 3rd the step, H.323 on the acting server port pool that defines in the first step being set, start H.323 acting server;

It is acting server that the 4th step, private net terminal are specified the gatekeeper, to acting server transmission register requirement H.323;

The 5th step, after H.323 acting server is received the register requirement of private net terminal, judge the whether for the first time registration of this terminal; If then in port pool, obtain a port that is not taken, and on this port, intercept by other terminal;

The 6th step, H.323 acting server is revised the login request message receive, the registered address be revised as after the conversion of acting server static network address H.323 public network address and the port of H.323 intercepting for this terminal on the acting server, send registration message then to the gatekeeper;

The 7th step, gatekeeper authenticate after receiving the register requirement of acting server H.323, authentication is passed through, and registers for the first time if find this private net terminal, then adds the log-on message of this terminal, registered if find this private net terminal, upgraded the registration of this private net terminal; If authentication is not passed through, then forwarded for the 9th step to;

The 8th step, gatekeeper send acknowledge message to acting server H.323, and H.323 acting server is received this private net terminal information of record after the acknowledge message, and send acknowledge message to this private net terminal, and registration finishes;

The 9th step, gatekeeper send refuse information to acting server H.323, and H.323 acting server discharges the listening port that distributes for this private net terminal in the 5th step after receiving refuse information, and sends refuse information to this private net terminal, the registration end.

2. register method according to claim 1 is characterized in that: the port number in the described first step middle port pond and H.323 the number of the private net terminal that will act on behalf of of acting server equate.

3. register method according to claim 1 is characterized in that: private net terminal registered address in the register requirement of H.323 acting server transmission is the private net address of this terminal and a listening port on the terminal in described the 4th step.

4. register method according to claim 1 is characterized in that described method also comprises the step of private net terminal cancel register:

Step 1, private net terminal send the message of cancel register to acting server H.323;

Step 2, H.323 acting server is released to the listening port of this terminal distribution after receiving this message, sends the message of cancel register then to the gatekeeper;

After step 3, gatekeeper receive the deregister message of acting server H.323, send cancel register to acting server H.323 and confirm;

Step 4, after H.323 acting server receives that gatekeeper's cancel register is confirmed, transmit this message to private net terminal, cancel register finishes.

5. according to claim 1 or 4 described register methods, it is characterized in that described method comprises that also the gatekeeper cancels the step of private net terminal registration:

Steps A, gatekeeper send the message of cancel register to acting server H.323;

Step B, H.323 acting server is released to the listening port that the registration terminal that is cancelled distributes after receiving this message, sends the message of cancel register then to this private net terminal;

After step C, private net terminal are received the deregister message of acting server H.323, send cancel register to acting server H.323 and confirm;

Step D, after H.323 acting server receives that the cancel register of private net terminal is confirmed, transmit this message to the gatekeeper, the gatekeeper cancels the private net terminal registration and finishes.

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