JP2003224580A - Network address converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To process IP address conversion at a high speed and to realize the VOIP connection of high quality with less delay between a private network using a private address and the Internet using a global address in the case of performing communication by using H.323 on an IP network. <P>SOLUTION: In an IP address analysis part 710, an address conversion table 600 is referred to and whether or not it is a conversion object packet is decided. Also, in a signal analysis and separation part 730, whether the conversion object packet is a call control signal or a sound signal is decided, and in the case of the call control signal, address information inside a payload is converted in a payload information conversion part 740. For the processings of the IP address analysis part and the signal analysis and separation part, etc., parallel processings are performed by using a plurality of packet high-speed processing blocks 790(1) to 790(n) to realize the high-speed relay processing of an IP packet. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network address translation device, and more particularly to a network address translation device when voice communication is made between endpoints connected to networks having different address systems.

[0002]

2. Description of the Related Art An example of a conventional address translation system is
It is described in Japanese Patent Application Laid-Open No. 2001-156852 "Network Address Translation Device". In this conventional system, the IP address in the header part of the received IP (Internet Protocol) packet is converted between the global IP address and the private address, and
VoIP (Voice) that performs voice communication on the IP network
ITU-which is a protocol of over Internet Protocol)
The H.T. In 323, the address information in which the IP address and the port number of the transmission / reception side stored in the payload part of the packet are set is also converted to realize VoIP communication between different IP networks.

[0003]

However, the above-mentioned conventional system has the following problems. The first problem is that H.264. In voice communication using the H.323 protocol, a gatekeeper, which is an address resolution system, is essential on both the private network side and the global network side. The reason is that the address translation table is created based on the address resolution message between the gatekeepers on the private network side and the global network side.

The second problem is that it is difficult to disperse the address translators. The reason is that since the address translation table is created based on the address resolution message, the address translation of a series of call control messages,
Since it is necessary to perform address translation of voice packets in the same system until the completion of the call, it is not possible to disperse the systems in the sending direction and the receiving direction for load distribution and to cope with system switching at the time of failure. There is.

The third problem is that H.264. Since the address conversion table is created based on the signal used in the H.323 protocol, there is a problem that it cannot be applied to other voice communication protocols.

An object of the present invention is to connect a plurality of IP networks using different address systems such as a private address and a global address to each other and receive the received IP.
IP header information in the packet and H.264. The address information that sets the IP address and port number of the sending and receiving side stored in the payload part of the packet for use with the H.323 protocol is converted into a private address and a global address, and the voice signal is converted into an IP packet. H. making the transfer It is to provide a network address translation device compatible with the H.323 protocol.

Another object of the present invention is to generate an IP address conversion table by cooperating with a gatekeeper, which is an address resolution system on the global network side, regardless of the network configuration on the private network side, and use a different address system. It is to provide a system capable of interconnecting a plurality of IP networks.

Still another object of the present invention is to distribute a network address translation device by performing address translation according to a translation rule specified in an address translation table regardless of a call state, a packet type, and a protocol. The purpose is to provide a system that enables system switching and protocol changes due to placement and failures.

Another object of the present invention is to provide a system in which a plurality of processing blocks perform parallel processing on a voice packet, which is required to have a real-time property, so that the address translation can be speeded up.

[0010]

According to the present invention, there is provided a network address translation device for performing voice communication between endpoints respectively connected to networks having different address systems, which includes an address translation table and a transmission address. A means for identifying a call control signal packet or a voice signal packet in response to reception of a packet for voice communication from the original endpoint, and a protocol analysis for the call control signal packet to perform a payload analysis of the packet. Means for converting the address information, which is a set of the transmitting and receiving side address and the port number stored in, according to the address conversion table; and, for the voice signal packet, the address information stored in the header part of the address information. And means for converting according to the conversion table. Network address translation device is obtained, characterized in that.

The contents of the address conversion table are characterized in that they are downloaded from a maintenance device or a gatekeeper via a network. Further, it is characterized in that the address conversion for the voice signal packet is simultaneously processed by a plurality of address conversion function blocks.

The operation of the present invention will be described. In the present invention, a plurality of IP networks that use different systems of private addresses and global addresses are connected to each other, and the private address of a received IP packet is converted into a global address to transfer a voice signal as an IP packet. The network address conversion device compatible with the H.323 protocol is provided with means for receiving the IP address conversion table notified from the gatekeeper or the maintenance device.

Further, when the IP packet is received, the address translation table is referred to, it is determined whether the IP packet is an address translation target IP packet, and the IP address translation target IP packet is separated into a call control signal and a voice signal or another signal. The header part of the IP packet is rewritten according to the address conversion table. Then, according to the address conversion table, H.264. The address information in which the IP address and the port number of the transmission / reception side stored in the payload portion of the packet for use in the H.323 protocol are set is rewritten.

Further, since the IP address conversion is carried out based on the address conversion table regardless of the state of the call control sequence, the type of packet, and the protocol, it becomes possible to perform the address conversion of any IP packet at any timing. H.3 distributed distribution and switching at the time of a failure. Three
23 can be supported.

Further, particularly in the case of IP address conversion of a voice signal which requires real-time processing, it is processed by separating it from a control signal packet which requires time for analysis / conversion processing, arranging a plurality of IP address conversion processings, and processing them simultaneously. Realization of higher speed and real-time performance.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a diagram showing an outline of a network system using a network address translation device according to an embodiment of the present invention and an operation relating to a call between endpoints. In FIG. 1, an IP network 100 using a private address has a plurality of endpoints (in this example, only EP200 is shown).
An IP network 110 that has a global address and also has multiple endpoints (EP
210), a gatekeeper GK310, and a maintenance device 500. Between these IP networks, a network address translation device NAT4
00 is arranged.

FIG. 2 is a functional block diagram showing an example of the address translation device NAT400. Referring to FIG.
A P address conversion table 600 is provided, and an IP address conversion table 60 is provided from the gatekeeper GK 310 or the maintenance terminal 500 to the address conversion device NAT 400 at the time of system initialization or system change.
0 is registered in advance. Processing S1 in FIG. 1 shows the processing at the time of registration, and FIG. 5 shows an example of the registered contents of the IP address conversion table.

The address translation device NAT400 further includes
An IP address analysis unit 710 that analyzes the IP address of the received IP packet to determine whether the packet is an address translation target packet, a header translation unit 720 that rewrites the IP address of the IP header unit, and a translation target IP packet as a call control signal. A signal analysis / separation unit 730 that separates into a voice signal or another signal and a protocol of a control signal are developed,
H. A payload information conversion unit 740 that rewrites address information that sets the IP address and port number of the transmitting and receiving side stored in the payload part of the packet for use in the H.323 protocol, and the packet and voice signal after the address conversion of the control signal. Or other signal IP
A packet transmission processing unit 760 that receives an IP packet from the checksum calculation unit 750 that rewrites the checksum information in the header unit and the TCP / UDP header unit, and the IP address analysis unit 710 or the checksum calculation unit 750 and passes it to the packet transmission / reception unit 770. And a packet transmitting / receiving unit 770 that transmits / receives IP packets.

In FIG. 2, n (n is an integer of 2 or more) identical blocks are provided in parallel as the packet high-speed processing blocks 790 (1) and 790 (n), whereby simultaneous parallel processing is performed. By performing the above, high speed processing is enabled.

Next, the transmission / reception sequence of FIG. 1 operates as follows. First, the maintenance terminal 500 or the gatekeeper 3
From 10 the information of the IP address conversion table 600 is notified to the address conversion device 400 (process S1).

IP using private IP address
In order to transmit a participation request message for permitting voice communication, telephone number and IP address resolution from the endpoint 200 located in the network 100 to the gatekeeper 310, first, the participation request message is sent to the address translation device 400. Send (process S2).
The address translator 400 translates the IP address information of the IP header 800 and the DATA unit 803 included in the IP packet according to the data registered in the IP address translation table 600.

Specifically, in the IP header 800, the source IP address 811 and / or the destination IP address 812 or both are converted, and the DATA section 8 is converted.
03, IP address information unique to the call control protocol, for example, H.264. 323 Protocol Message Admiss
dest call Signal A included in ion Request (ARQ)
All relevant information such as ddress is converted and transmitted to the gatekeeper 310 (process S3).

The gatekeeper 310 is an H.264 terminal. A response message is transmitted according to the procedure of the H.323 protocol (process S
4). The message from the gatekeeper 310 is also transmitted to the address translation device 400, and the IP address is transmitted in the same manner as the above procedure.
The address information is converted and transmitted to the endpoint 200 (process S5).

By similarly processing these conversion operations for a series of call control protocol messages and voice packets, a plurality of IP networks using different address systems of private addresses and global addresses can be connected to each other.

Next, the processing procedure in the address translation device 400 will be described with reference to FIG. The processing flow will be described with reference to the flowchart of FIG. 4 shows IP
It is a format diagram which shows the structure of a packet.

First, the IP packet transmitting / receiving unit 770 sends an IP
Upon receiving the packet, the IP address analysis unit 710 then analyzes the IP header 800 (see FIG. 4) to check whether the packet is an IP packet (step S11), and the source IP address 811 and the destination IP address 812 are checked. IP address conversion table 60 for either or both
By referring to 0, it is checked whether it is a conversion target (steps S12 and S13). For packets that are not IP packets and packets that are not IP address translation targets, the process is terminated and the process proceeds to the packet transmission processing unit 760 (step S1).
9).

For the packet for which the IP address is to be translated, the header translation unit 720 sends the source IP address 81.
IP address conversion processing is performed for one or both of 1 and the destination IP address 812 according to the IP address conversion table 600 (step S14).

Next, in the signal analysis / separation unit 730 for separating the call control signal and the voice signal or other signals, the transmission source in the UDP header 810 or the TCP header 802 based on the information of the protocol 810 in the IP header 800. The protocol is specified from the port number 813 and the destination port number 814 (step S15), and the H.264 standard is set. If it is a call control signal such as 323 (step S16), the payload information conversion unit 7
The processing shifts to 40, and if the signal is not a call control signal, it is determined to be a voice packet or other signal that does not require payload information conversion, and the processing shifts to the checksum calculation unit 750.

For the call control signal, the DATA unit 802
The call control signal protocol included in 32
In the payload information conversion unit 740, which rewrites the address information in which the IP address and the port number of the transmission / reception side stored in the payload portion for use in the 3 protocols are rewritten, rewriting is performed according to the IP address conversion table 600 (step S17).

The checksum calculator 750 recalculates and rewrites the checksum information of the IP header and TCP / UDP header of the packet and voice signal or other signal after the address conversion of the control signal (step S18). ).

The packet transmission processing unit 760 receives the packet from the IP address analysis unit 710 or the checksum calculation unit 750 and transfers the packet to the packet transmission / reception unit 770 (step S19).

For those requiring real-time processing such as voice packet processing, the IP address analysis unit 71 is used.
0, the header conversion unit 720, the signal analysis / separation unit 730, the checksum calculation unit 750, and the packet transmission processing unit 760 need to be performed at high speed, so n packet high-speed processing blocks 790 that perform these operations are arranged. By performing processing in parallel, high-speed processing is realized.

Since these processes can be performed independently for each IP packet and can be processed without being aware of call control messages, voice signals, etc., a plurality of address translation devices 400 are arranged, It is possible to deal with signal load distribution and switching at the time of failure without any problem.

As another embodiment of the present invention, the basic configuration is as described above, but the gatekeeper is not arranged in the IP network 100 using the private IP address, but the gatekeeper 300 is arranged in both networks. Then, the message from the endpoint 200 is relayed through the gatekeeper 300 and the address translation device 400
It may be configured to send to.

SIP specified in RFC2543
, MGCP specified in RFC2705, H.264, etc. Three
Even in any VoIP protocol other than H.23 and other communication protocols, by rewriting the address information by the address conversion table notification processing S1 of FIG. 1, it becomes possible to support the conversion function of the corresponding protocol and perform communication.

A plurality of address translation devices 400 are arranged,
It is possible to deal with signal load distribution, switching at the time of failure, etc. without any problem, since it is not associated with the control signals and packets before and after.

Further, it is possible to cope with the communication between the IP network 100 which uses a private address and the IP network 101 which uses a private address whose address system is different from that of the IP network.

Further, it is possible to support communication between the IP version 4 network and the IP version 6 network.

[0039]

As described above, the present invention has the following effects. A first effect is that a plurality of IP networks that use different address systems such as a private address and a global address are connected to each other, and the IP header information in the received IP packet and the H.264 standard. The address information, which is stored in the payload part of the packet for use in the H.323 protocol and has the set IP address and port number of the transmitting and receiving side, is converted between the private address and the global address, and the information is transferred between different IP networks. This means that voice communication has become possible.

The second effect is that the address conversion table can be converted from the gatekeeper or the maintenance device, and it is possible to easily deal with the increase or decrease of the endpoint and the change of the IP address.

A third effect is that the control signal packet and the voice packet are separated, and the IP address conversion in the voice packet, which requires real-time property, is executed in parallel by a plurality of processing blocks, thereby increasing the speed. It was realized and real-time property was improved.

The fourth effect is that the IP address conversion is performed by using the address conversion table designated in advance, thereby enabling the voice communication without being influenced by the control messages and packets before and after. is there.

[Brief description of drawings]

FIG. 1 is a diagram showing the positioning of an address translation device of the present invention in a network and an operation sequence.

FIG. 2 is a functional block diagram of an embodiment of the present invention.

FIG. 3 is a processing flow of an embodiment of the present invention.

FIG. 4 is a format diagram showing a configuration of an IP packet.

5 is a diagram showing a specific example of an IP address conversion table 600. FIG.

[Explanation of symbols]

100 IP network using private IP address 110 IP network using global IP address 200 Endpoint using private IP address 210 Endpoint using global IP address 310 Gatekeeper 400 Address translation device 500 Maintenance terminal 600 IP address translation table 710 IP address analysis unit 720 Header conversion unit 730 Signal analysis separation unit 740 Payload information conversion unit 750 Checksum calculation unit 760 Packet transmission processing unit 770 Packet transmission / reception unit 790 Packet high-speed processing block

Claims (3)

[Claims] 1. A network address conversion device in the case of performing voice communication between endpoints respectively connected to networks having different address systems, which comprises an address conversion table and a voice communication from a source endpoint. Means for identifying a call control signal packet or a voice signal packet in response to reception of the packet, and for the call control signal packet, a protocol analysis is performed and an address of the transmitting / receiving side stored in the payload part of the packet A means for converting the address information in which the port number is set according to the address conversion table; and a means for converting the address information stored in the header portion of the voice signal packet according to the address conversion table. A network characterized by including Click the address conversion apparatus. 2. The network address translation device according to claim 1, wherein the contents of the address translation table are downloaded from a maintenance device or a gatekeeper via a network. 3. The network address translator according to claim 1, wherein address translation for the voice signal packet is simultaneously processed by a plurality of address translation functional blocks.