JP4350029B2 - Address translation system - Google Patents

Description

The present invention relates to a system for interconnecting networks according to the same protocol or networks according to different protocols.

The Internet (IP) network such as the Internet is rapidly developing. With the rapid increase in Internet users, the rate of data communication in the communication network is increasing. Telecom operators are building next-generation IP-based communication networks and are considering the fusion of data and voice communications. VoIP (Voice over IP) is a technology for transmitting voice information over an IP network. In VoIP, a virtual communication path (session) is first set between communication devices. IP packetized voice data is transferred on the set communication path. A session control protocol is required to control session establishment, maintenance, and disconnection between communication devices.
The Internet Engineering Task Force (IETF) has specified SIP (Session Initiation Protocol) (IETF RFC2543) to establish and terminate IP multimedia communication sessions. SIP is attracting attention as a VoIP session control protocol because of its high functionality extensibility.
SIP is an application protocol that uses transport mechanisms such as TCP (Transmission Control Protocol) and UDP (User Datagram Protocol).
SIP is a text-based protocol and consists of a header part that carries a request or response and a message body that describes the contents of the session. For example, SDP (Session Description Protocol) (IETF RFC2327) is applied to the SIP session description.
SIP employs a client-server model architecture. The outgoing client sends a SIP request to the incoming client's proxy (SIP server). The SIP server uses DNS (Domain Name System) or the like to resolve a communication destination address and establish a session between terminals.
The SIP server has a Proxy mode and a Redirect mode depending on its role. Proxy mode is a method in which a proxy server mediates a session establishment request between an outgoing client and an incoming client. The Redirect mode is a method in which a calling client directly connects to an incoming client using information on a destination received from a SIP Redirect server.
Hereinafter, a SIP connection procedure using a SIP server in Proxy mode will be described. When the IP network terminal x starts voice communication with the IP network terminal y using SIP, the terminal x transmits a call setting request (INVITE) to the SIP server. The SIP server specifies the location information of the terminal y and transmits a call setting request. The terminal y transmits a response indicating acceptance of the call. This response is transmitted to the terminal x via the SIP server through which the call setting request has passed. Terminal x confirms receipt of the response by sending an ACK request to terminal y. The ACK request is transferred by the SIP server or directly transmitted to the terminal y. As described above, communication between the terminal x and the terminal y becomes possible. Normally, the call setting request and response include information (session description) for transferring user information (voice packet) between the terminal x and the terminal y. SDP or the like is applied to the session description. The terminal x (terminal y) sends the user information to the destination designated by the terminal y (terminal x).
According to the specifications of SIP and SDP, information on terminals and SIP servers can be specified by IP addresses.
On the other hand, with the rapid spread of IP networks, technology for interconnecting areas with different address systems has become important.
For example, a method (IETF RFC1631) using a NAT (Network Address Translator) technique is known as a technique for interconnecting a network according to a private address and a network according to a public address.
NAT translates private IPv4 addresses and public IPv4 addresses. Basic NAT rewrites either the source address or the destination address when a datagram passes between two areas connected by a NAT router. When the address space of the private network and the address space of the public network collide, twice NAT technology is often used to resolve the address conflict. Twice NAT technology rewrites both the source address and the destination address when a datagram passes between two areas connected by a twice NAT router.
To resolve address conflicts, Twice NAT works as follows. When Host-A in the private area starts communication with Host-X in the public area, Host-A sends a DNS address inquiry packet of Host-X. DNS-ALG (Domain Name Service-Application Level Gateway) captures this packet, converts the address for Host-X into a routable address (Host-XPRIME) in the private area, and returns it to Host-A. When DNS address resolution is complete, Host-A starts communication with Host-XPRIME. When this packet passes through Twice NAT, the source address is rewritten to the address that NAT has, and the destination address is rewritten to Host-X. The return packet from Host-X is also converted in the same way. Details of the operation of the DNS-ALG are described in IETF RFC2694.
The above example is a technique used when the communication protocol of the network to which a certain terminal belongs and the network to which the communication partner terminal belongs are the same. If the communication protocol of the network to which a certain terminal belongs and the network to which the communication partner's terminal belongs are different, for example, a network using IPv4 as a protocol (hereinafter referred to as IPv4 network) and a network using Internet Protocol version 6 (hereinafter referred to as IPv6 network). NAT-PT (IETF RFC2766), SOCKS64 (IETF RFC3089), and the like are known as conversion methods for connecting (calling).
In either case, the IP packet format is basically converted between IPv4 and IPv6.
For example, an IPv4 address and an IPv6 address are converted. An apparatus that performs this conversion is hereinafter referred to as a translator. The translator needs to create and maintain the correspondence between IPv4 address and IPv6 address before conversion for conversion. When this correspondence is dynamically created each time communication occurs, DNS (Domain Name System) name resolution is used as a trigger (see ASCII Publishing, Internet RFC Encyclopedia, pp323-329).
DNS is a system that converts human-friendly names (strings) such as web URLs into IP addresses. Hereinafter, the operation of converting a name to an IP address is called name resolution. Today, almost every application on the Internet uses this DNS to obtain the IP address of the other party.
Using this fact, NAT and translators constantly monitor DNS messages exchanged at the start of communication, and use name resolution request messages as a trigger for creating translation information (IP address correspondences, etc.). Specifically, when name resolution is performed for a certain name of an IPv6 terminal, if the response IP address is IPv4, the IPv4 address is rewritten to an IPv6 address and sent back to the IPv6 terminal.
Then, associate the rewritten IPv4 address with the rewritten IPv6 address.
In other words, DNS-ALG intercepts and rewrites the name resolution response message, and dynamically creates conversion information based on the information before and after this rewriting.

  The IP packet has an IP header including packet transfer information, a TCP / UDP header, and application data. Translators such as NAT and NAT-PT do not convert IP addresses included in application data.

  On the other hand, as described above, SIP and SDP can set an IP address in application data.

However, when area A and area B are interconnected by an address translation device, and terminals belonging to area A and terminals belonging to area B perform communication by SIP, conventional NAT and translators use IP addresses set in SIP and SDP. There is a problem in that communication between terminals by SIP cannot be performed because no conversion is performed.
An object of the present invention is to provide a SIP message conversion method that enables communication between terminals by SIP even when a network to which a certain terminal belongs and a network to which a communication partner terminal belongs are different.

To solve the above problem, the present invention is a method for processing a message including a first part and a second part, comprising:
A first conversion process for converting information of the first portion from information according to the first protocol (or address system) to information according to the second protocol (or address system);
A process for determining whether the second part needs to be converted;
A second conversion process of converting information according to the first protocol into information according to the second protocol is performed on the information of the second portion determined to be necessary for conversion. The order of the first conversion process and the second conversion process is arbitrary.

  These operations use the first server and the second server, perform the first conversion process on the first server, and transfer at least the second part information from the first server to the second server. Then, the second server extracts the parameter that needs to be converted from the second part, and the second server performs the second conversion process on the extracted parameter, and the second conversion process is performed. The information of the second part may be transferred from the second server to the first server.

  Alternatively, a plurality of processors connected by an internal bus in a single server may jointly perform processing. A plurality of programs running on a single processor in a single server may perform processing together.

  As a typical application, the first part is an IP header, the second part is a payload containing a SIP message, one of the first protocol and the second protocol is IPv4 and the other is In IPv6, the information to be converted is an address.

  The address translation device according to the present invention is an address translation device connected to both the first network according to the first protocol and the second network according to the second protocol, and includes the first protocol and the second protocol. A storage unit that holds conversion rules for converting protocols to each other, a first address according to the first protocol of input information, and a second address according to the second protocol based on the conversion rules as protocols. A conversion unit for converting; and a function of outputting the input information and the conversion rule.

  The output destination is another server outside the apparatus, another block in the apparatus connected by the internal bus, or another processing block in the same processor.

In a preferred example, input information that has been subjected to protocol conversion using the input information and conversion rules at the output destination is re-input to the address conversion device.
In the present invention, an address translation device for connecting a network A according to a certain protocol P and a network B according to a certain protocol Q, the address translation device having an address translation function for mutually converting an address according to the protocol P and an address according to the protocol Q And a detection function for detecting communication according to a specific protocol, the address conversion function converts the address described in the first area of the communication data, and communication is detected when communication according to the specific protocol is detected. In order to convert the address described in the second area of the data, conversion information including the correspondence between the address in the protocol P and the address in the protocol Q is created.

More specifically, in a communication network interconnecting networks having different address systems, at least the following two means are provided in addition to the conventional address translation device represented by NAT or translator. That is, (1) means for detecting an SIP message transmitted / received between different areas by the address translator, and (2) SIP for converting the IP address set in the SIP and SDP according to the address translation scheme of the address translator. Message conversion means is provided.
The address translation device detects the SIP message by the IP address of the SIP server, the combination of the IP address of the SIP server and the port number, or the port number. When an address translation device interconnecting networks having different address systems detects a SIP message transmitted from a terminal or a SIP server, the SIP message detection means is activated.
The SIP message conversion means includes at least the following three functions. (1) SIP message conversion target parameter detection function, (2) Conversion rule corresponding to the address conversion method provided by the address conversion device, and (3) Function to rewrite SIP message using the conversion entry of the address conversion device. is there. The address translation device creates a translation entry based on the request of the SIP address translation device. The address translation device rewrites the header information of the packet transmitted / received between the communication terminals based on the translation entry.
The function deployment method of the SIP message conversion means has the following three forms.
The first deployment method includes a SIP address conversion device including SIP message conversion means. The SIP address translation device rewrites the IP address included in the SIP message by using the translation entry of the address translation device.
In the second deployment method, the address translation device has a SIP message conversion target parameter detection function, and adds identification information (tag) to the conversion target parameter. The SIP address translation device has a function of rewriting the translation rule and the IP address included in the SIP message. The SIP address translator rewrites the IP address included in the SIP message using the translation entry of the address translator.
In the third deployment method, the address translation device includes SIP message translation means.
If the present invention is applied, the IP address information included in the SIP message transmitted / received between different areas is converted by using the translation entry of the address translation device. Therefore, it is possible to provide a voice communication service by VoIP between terminals belonging to different areas.
The communication network according to the present invention has the following features.
(1) In a communication network in which a network A conforming to a certain protocol P and a network B conforming to a certain protocol Q are connected by an address translation device,
The address translation device includes a function for mutually converting protocol P to protocol Q, a function for detecting SIP communication, information and communication means necessary for communicating with the server device, and the server device when SIP communication is detected. With the function of creating conversion information including the correspondence between addresses in protocol P and addresses in protocol Q,
The server device is necessary for communicating with the address conversion device, and conversion information and means necessary for mutually converting the protocols P and Q in the address conversion device when the information to be converted is included in the SIP communication. Information and communication means,
In SIP communication from network A according to protocol P to network B according to protocol Q, the address conversion device detects SIP communication, and the server device refers to the conversion information provided in the address conversion device by referring to the conversion information provided in the address conversion device. An address according to P is converted from an address according to protocol Q, and communication from network A according to protocol P to network B according to protocol Q refers to the conversion information provided in the address conversion device, and the address according to protocol P is determined according to protocol Q. A communication network characterized by converting to an address.

  As described in (1) above, if the address translation device according to the present invention interconnects a network according to the IPv4 address and a network according to the IPv6 address, and the SIP address translation device according to the present invention rewrites the IP address included in the SIP message, Voice communication using SIP between terminals belonging to the network and terminals belonging to the IPv6 network becomes possible.

As another aspect of the present invention, the address translation device according to the present invention interconnects the network 1 according to the IPv4 private address and the network 2 according to the IPv4 global address, and the SIP address translation device according to the present invention writes the IP address included in the SIP message. In other words, voice communication using SIP between the terminals belonging to the network 1 and the terminals belonging to the network 2 becomes possible. That is, the configuration is as shown in (2) below.
(2) In a communication network in which a plurality of networks A1, A2 conforming to a certain protocol P are connected by an address translation device,
The address translation device detects the SIP communication, the function to mutually convert the protocol P of the network A1 to the protocol P of the network A2, the function to detect SIP communication, the information and communication means necessary for communicating with the server device In this case, the server device has a function of creating conversion information including a correspondence relationship between the address on the network A1 and the address on the network A2 in cooperation with the server device, and the server device includes the conversion target information in the SIP communication. In the address translation device, the translation information and means necessary for mutually converting the address in the network A1, the address in the network A2, and the information and communication means necessary for communicating with the address translation device. Prepared,
In the SIP communication from the network A1 to the network A2, the address conversion device detects the SIP communication, and the server device refers to the SIP communication information from the address in the network A1 by referring to the conversion information provided in the address conversion device. The communication from the network A1 in accordance with the protocol P to the network A2 in accordance with the protocol P is converted from the address in the network A1 to the address in the network A2 by referring to the conversion information provided in the address conversion device. A communication network characterized by conversion.
(3) The address conversion device further has a function of detecting conversion target information included in SIP communication and adding identification information, and the server device detects the conversion target using the identification information. The communication network according to (1) or (2).
(4) The address conversion device further has a function of associating identification information with SIP communication information, and the address conversion device further has a function of deleting conversion information corresponding to the identification information when SIP communication ends. The communication network according to (3).
(5) The communication according to any one of (1) to (4), wherein the address conversion device detects SIP communication based on destination information or destination information and its port information or port information. network.
(6) In a communication network in which a network A conforming to a certain protocol P and a network B conforming to a certain protocol Q are connected by an address translation device,
The address translation device has a function for mutually converting protocol P to protocol Q, a function for detecting SIP communication, a function for creating translation information including correspondence between addresses in protocol P and addresses in protocol Q, and SIP. A means for generating conversion information necessary for mutually converting the protocols P and Q when the communication includes conversion target information;
In the SIP communication from the network A according to the protocol P to the network B according to the protocol Q, the address conversion device detects the SIP communication, and the SIP communication information refers to the address according to the protocol Q from the address according to the protocol P with reference to the conversion information. Further, the communication from the network A according to the protocol P to the network B according to the protocol Q is characterized in that the address according to the protocol P is converted from the address according to the protocol P with reference to the conversion information included in the address conversion device. Communication network.
(7) In a communication network in which a network A1 and a network A2 according to a certain protocol P are connected by an address translation device,
The address translation device creates translation information including the function of mutually converting the protocol P of the network A1 into the protocol P of the network A2, the function of detecting SIP communication, and the correspondence between the addresses of the network A1 and the addresses of the network A2. A function and means for generating conversion information necessary to mutually convert the address of the network A1 and the address of the network A2 when the conversion target information is included in the SIP communication,
In the SIP communication from the network A1 to the network A2, the address conversion device detects the SIP communication, and the SIP communication information is converted from the address of the network A1 to the address of the network A2 with reference to the conversion information. The communication from the network A1 to the network A2 is performed by referring to the conversion information included in the address conversion device and converting the address of the network A1 to the address of the network A2.

Features of the server device embodying another aspect of the present invention are as follows.
(A) In a communication network in which a network conforming to a certain protocol P and a network conforming to a certain protocol Q are connected by an address translation device,
The address translation device includes a function for mutually converting protocol P to protocol Q, a function for detecting SIP communication, information and communication means necessary for communicating with the server device, and the server device when SIP communication is detected. With the function of creating conversion information including the correspondence between addresses in protocol P and addresses in protocol Q,
Translation information and means necessary for mutual conversion of protocols P and Q in the address translation device when the information to be translated is included in SIP communication, and information and communication means necessary for communication with the address translation device A server device comprising:
(B) In a communication network in which a plurality of networks A1 and A2 conforming to a certain protocol P are connected by an address translation device,
The address translation device detects the SIP communication, the function to mutually convert the protocol P of the network A1 to the protocol P of the network A2, the function to detect SIP communication, the information and communication means necessary for communicating with the server device In this case, the server device has a function of creating conversion information including the correspondence between the address on the network A1 and the address on the network A2 in cooperation with the server device, and the address when the conversion target information is included in SIP communication. The conversion apparatus includes conversion information and means necessary for mutually converting the address on the network A1 and the address on the network A2, and information and communication means necessary for communicating with the address conversion apparatus. Server device.

The address translation device of the present invention is
(1) An address translation device for connecting a network A conforming to a certain protocol P and a network B conforming to a certain protocol Q,
A conversion function for mutually converting the protocol P and the protocol Q;
A communication function for communicating with the server device;
A conversion information creating function for creating conversion information including a correspondence relationship between an address in protocol P and an address in protocol Q;
An address conversion device, wherein the detected SIP communication data is transferred to the server device, and the server device receives SIP communication data whose protocols are mutually converted based on the conversion information.
(2) In a communication network in which a plurality of networks A1, A2 conforming to a certain protocol P are connected by an address translation device,
The server device includes conversion information and means necessary for mutually converting the address on the network A1 and the address on the network A2 in the address conversion device when the information to be converted is included in the SIP communication, and the address conversion device. With necessary information and communication means to communicate with
The function of mutually converting the protocol P of the network A1 into the protocol P of the network A2, the function of detecting the SIP communication, the information and communication means necessary for communicating with the server device, and the above when the SIP communication is detected An address translation device comprising a function of creating translation information including a correspondence relationship between an address on the network A1 and an address on the network A2 in cooperation with the server device.
(3) The address translation device according to claim 1 or 2, further comprising a function of detecting information to be converted included in SIP communication and adding identification information.
(4) The address conversion device further has a function of associating identification information with SIP communication information, and the address conversion device further has a function of deleting conversion information corresponding to the identification information when SIP communication ends. The address conversion device according to (3).
(5) The address conversion device as described above, wherein SIP communication is detected based on destination information or destination information and its port information or port information.
(6) In a communication network in which a network A conforming to a certain protocol P and a network B conforming to a certain protocol Q are connected by an address translation device,
It has a function to mutually convert protocol P to protocol Q, a function to detect SIP communication, and a function to create conversion information including the correspondence between addresses in protocol P and addresses in protocol Q.
When the conversion target information is included in the SIP communication, there is provided means for generating conversion information necessary for mutually converting the protocols P and Q, and rewriting the content of the communication with reference to the conversion information. Address translation device.
(7) In a communication network in which a network A1 and a network A2 according to a certain protocol P are connected by an address translation device,
A function to mutually convert the protocol P of the network A1 to the protocol P of the network A2, a function to detect SIP communication, and a function to create conversion information including the correspondence between the addresses of the network A1 and the addresses of the network A2 ,
A means for generating conversion information necessary for mutually converting the address of network A1 and the address of network A2 when conversion target information is included in SIP communication,
When the conversion target information is included in the SIP communication, there is provided means for generating conversion information necessary for mutually converting the address of the network A1 and the address of the network A2, and rewriting the contents of the communication with reference to the conversion information. An address translation device characterized by that.
(8) The address converter according to (7), wherein SIP communication is detected based on destination information, or destination information and its port information, or port information.

  As is clear from the above embodiments, the present invention enables the SIP address translation device 2 to rewrite the contents of the SIP message by utilizing the translation information of the address translation device 1, thereby enabling SIP between terminals existing in different areas. Enables voice communication. If the address translation device 1 has a function of detecting a conversion target parameter of the SIP message and adds identification information (tag) to the conversion target parameter, the processing of the SIP address conversion device 2 can be reduced. Furthermore, if the address translation device 1 has a function of detecting the correspondence between the identification information and the call leg and the start and end of the SIP session, the address translation device 1 can delete the corresponding entry at the end of communication. Therefore, finer SIP communication control becomes possible.

  If the address translation device 1 includes SIP message translation means, communication processing with the SIP message translation device 2 can be omitted.

  A first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration example of a SIP communication network according to the present invention. In this embodiment, the SIP communication network includes a network A7 and a network B8. Each SIP communication network includes a SIP server 5, a terminal 6, and a DNS server 4. In this embodiment, the network A7 uses an IPv6 address. In this embodiment, the network B8 uses an IPv4 address. The network A7 and the network B8 are connected by the address translation device 1.

  The address translation device 1 includes an IPv6 address / IPv4 address translation function, SIP message detection means, means for communicating with the SIP address translation apparatus 2, and means for communicating with the DNS-ALG 3.

  The SIP address translation device 2 includes means for managing information necessary for address translation of the SIP message and rewriting the contents of the SIP message.

  FIG. 6 shows the SIP protocol stack and message format. A packet including SIP is composed of an IP header 41, a TCP / UDP header 42, and a payload 43. The SIP is stored in the payload 43. SIP consists of start-line 44, message-header 45, and message-body 46. Start-line 44 indicates the type and destination of the SIP message. Message-header 45 includes SIP parameters. Message-body 46 indicates connection information logically set between terminals. SDP etc. are used for the description of Message-body.

  FIG. 7 shows a protocol stack for SIP communication between terminals belonging to different areas according to the present invention. The SIP server 5 and the terminal 6 are provided with SIP protocol stacks (41, 42, 43) shown in FIG. In the present embodiment, the address translation device 1 performs the IP header 41 translation processing (47), and the SIP address translation device 2 performs the SIP message translation processing (48).

  FIG. 2 shows a configuration example of the address translation device 1. The address translation device 1 includes an interface unit (IF) (19a, 19b, 19n) that accommodates lines (18a, 18b, 18n), a packet transfer processing unit 14, and a packet transfer control unit 13.

  The packet transfer processing unit 14 includes a distribution processing unit 15 that detects a SIP message, a conversion information storage unit 16 that stores information necessary for address conversion, and a packet conversion / processing unit 17 that converts a data packet. Prepare. The conversion information storage unit 16 includes a conversion information table 500.

  FIG. 19 shows an example of the table configuration of the conversion information table 500. The conversion information table 500 stores the correspondence between the IPv4 address 501 and the IPv6 address 502.

  Returning to FIG. 2, the description of the address translation device 1 will be continued. The distribution processing unit 15 that detects the SIP message detects the SIP message transmitted / received between the network A7 and the network B8 by any of the following means.

  When the destination of the SIP message from the network A (network B) to the network B (network A) is limited, the address translation device 1 detects the SIP message with the destination address of the packet header. The distribution processing unit 15 of the address translation device 1 stores the address information of the SIP message destination.

  The address translation device 1 may detect the SIP message by a combination of the destination address and the destination port number in the packet header. If you use TCP or UDP as the transport mechanism, the default port number for SIP is 5060.

  When the destination of the SIP message from network A (network B) to network B (network A) is not limited, the address translation device 1 detects the SIP message with the destination port number in the packet header. The distribution processing unit 15 of the address translation device 1 includes port number information used for SIP communication.

When receiving the IPv4 packet, the packet conversion / processing unit 17 searches the conversion information storage unit 16 and rewrites the IPv4 address into the IPv6 address. Further, when receiving the IPv6 packet, the packet conversion / processing unit 17 searches the conversion information storage unit 16 and rewrites the IPv6 address into the IPv4 address. At this time, it is possible to rewrite various information in addition to the IP address.
FIG. 4 shows the IPv4 packet format.
FIG. 5 shows the IPv6 packet format. When converting, not only the IP address but also this format is converted.

Returning to FIG. 2, the description of the address translation device 1 will be continued. The packet transfer control unit 13 includes a conversion entry registration processing unit 11 and a conversion entry generation processing unit 12.
The conversion entry registration processing unit 11 registers the conversion information in the conversion information storage unit 16.
The conversion entry generation processing unit 12 has a function of generating address conversion information.

  FIG. 3 shows a configuration example of the SIP address translation device 2. The SIP address translation device 2 has a configuration in which an interface unit (IF) (23a, 23b) that accommodates lines (24a, 24b), a memory 22, and a CPU 21 are connected by a bus 25.

  The memory 22 stores a SIP message conversion processing program 26, a conversion information inquiry processing program 27, and a conversion rule storage unit 28.

  The SIP message conversion processing unit 26 includes the conversion target parameter information table 412 shown in FIG. 25 and the SIP message processing routine 60 shown in FIG. 18, and converts the address information included in the SIP message.

  FIG. 25 shows an information table 412 including a conversion target parameter list. In this table, SIP and SDP parameters that can set IP addresses and port numbers are defined.

The conversion rule storage unit 28 stores parameter conversion rules for each address conversion method provided in the address conversion device 1. The address included in the SIP message is converted according to the conversion rule.
FIG. 26 shows a translation rule 413 when the address translation apparatus 1 performs address translation by the NAT-PT method. By storing the conversion rules 413 necessary for SIP message conversion in the memory, the conversion process is speeded up.

  The conversion information inquiry unit 27 performs a process of inquiring the address conversion device 1 for IP address conversion information.

A case will be described in which the terminal 6a of the network A in FIG. 1 performs voice communication using the SIP with the terminal 6b of the network B in accordance with the sequence shown in FIGS. At the start of communication, it is necessary to establish a session between the terminal 6a and the terminal 6b.

  Here, it is assumed that the SIP server 5a is set as the transmission destination of the SIP message in the terminal 6a.

The terminal 6a transmits INVITE requesting establishment of a session with the terminal 6b to the SIP server 5a (101).
FIG. 8 shows an example INVITE message 401 transmitted from the terminal 6a to the SIP server 5a. INVITE destination information is set in Start-Line. The Via header indicates the route of the SIP Request. A response to the SIP Request is transmitted from the receiving terminal to the calling terminal based on the via header information. The To header indicates the request destination, the From header indicates the request initiator, and Call-ID indicates the call identifier. The c parameter of Message-body indicates connection information, and the m parameter indicates a port number for receiving data. After the session is established, the voice information between the terminals is transmitted to the c parameter and the m parameter.

  Returning to FIG. 27, the description of the sequence is continued. When the SIP server 5a receives INVITE, the INVITE transmission destination is determined from the start-line destination information. When the domain name is set in the destination information, the SIP server 5a transmits a DNS inquiry to the DNS server 4a (102). The DNS server 4a resolves the name of the SIP server 5b in cooperation with the DNS-ALG 3 and the DNS server 4b (103). For example, the address translation method described in Japanese Patent Application Publication No. 2001-274419 is applied to the linkage method between the address translation device (TR) 1 and DNS-ALG3. DNS-ALG3 converts the IPv4 address b4 for the domain name of the SIP server 5b into a virtual IPv6 address vb6. The conversion information is stored in the conversion information table 500 of the conversion information storage unit 16 of the address conversion device 1.

The SIP server 5a acquires the virtual IPv6 address vb6 of the SIP server 5b as the INVITE transmission destination information (104), and transmits the INVITE to the virtual IPv6 address vb6 (105).
FIG. 9 shows a message example of the SIP message (INVITE) transmitted by the SIP server 5a.

  The address translation device 1 detects the SIP message (INVITE) by an IP address, a combination of an IP address and a port number, or a port number (106). The address translation device 1 transmits the detected SIP message (INVITE) together with information indicating the address translation method to the SIP address translation device (SIP-ALG) 2 (107). When the address conversion device 1 has one address conversion method, information on the address conversion method may be set in the SIP address conversion device in advance.

  When the SIP address conversion device 2 receives the SIP message, it starts the SIP message conversion processing routine 60 shown in FIG. 18 (108).

  FIG. 18 shows a SIP message conversion processing routine 60 in the first embodiment. The SIP address conversion device 2 compares the conversion target parameter list 412 with the received SIP message and extracts the conversion target parameters (61).

  If there is a parameter to be converted, it is checked whether the extracted parameter contains an IP address (62).

  If the extracted parameter includes an IP address, the address conversion method is determined (63). Next, referring to the conversion rule 413 in the conversion rule storage unit 28, the conversion target IP address is specified (64). For example, when the INVITE shown in FIG. 9 is received, the IP addresses to be converted are the IPv6 address sipa6 of the SIP server 5a and the IPv6 address a6 of the terminal 6a.

  If the address translation method of the address translation device 1 is masquerading, the port number included in the extracted parameter is also subject to translation.

  The translation information inquiry unit 27 of the SIP address translation device 2 transmits an address query request 600 including the translation target IP address “sipa6, a6” to the address translation device 1 (65, 109).

  FIG. 16 shows a message format of the address inquiry request 600. The address inquiry request is composed of a header portion 601 and request contents 602. The header unit 601 includes an ID (605), and associates an address inquiry request with a response. In Count (608), the number of IP addresses to be converted is set.

  The request content 602 includes an IP address type (IPv4, IPv6) (609), a translation target IP address (610), and a translation target port number (611) for each translation target IP address. The port number 611 is set when the port number is a conversion target.

The address translation device 1 receives the address inquiry request 600 and searches the translation information table 500 of the translation entry generation processing unit 12 using the translation target IP address.
If the translation target IP address exists in the translation information table 500 of the translation entry generation processing unit 12, the address translation device 1 sends an address inquiry request response (110, 66) including the translated IP address to the SIP address translation device 2. To do.
If the conversion target IP address does not exist in the conversion information table 500 of the conversion entry generation processing unit 12, the conversion entry registration processing unit 11 is activated and a conversion entry is set in the conversion information table 500 of the conversion information storage unit 16. The address translation device 1 transmits an address inquiry request response (110, 66) including the translated IP address “vsipa4, va4” to the SIP address translation device 2.

FIG. 17 shows a message format of the address inquiry request response 650.
The address inquiry request response includes a header part 601 and response contents 603. The response content 603 is a combination of the IP address type (620), IP address (621), port number (622) to be converted and the IP address type (623), IP address (624), and port number (625) after conversion. including.

  The SIP address translation device 2 receives the address inquiry request response and rewrites the IP address information included in the SIP message (67, 111). More specifically, sipa6 is changed to vsipa4 and a6 is changed to va4.

  The SIP address translation device 2 transmits a SIP message (INVITE) in which the IP address information is rewritten to the address translation device 1, and ends this routine (68, 112).

  If the conversion target parameter is not extracted in step 61, and if the IP address information is not included in the extraction parameter in step 62, the SIP address conversion device 2 does not rewrite the SIP message. The SIP address translation device 2 transmits a SIP message to the address translation device 1 (69), and this routine ends.

  Returning to FIG. 27, the description of the sequence diagram is continued. When receiving the SIP message (INVITE) from the SIP address translation device 2 (112), the address translation device 1 performs address translation of the IP packet header including the SIP message (113). Referring to the translation information table 500 of the translation information storage unit 16 of the address translation device 1, the destination address is the real IPv4 address “sipb4” of the SIP server 5b, and the source address is the virtual IPv4 address “vsipa4” of the SIP server 5a. Respectively.

  FIG. 10 shows an example of a SIP message (INVITE).

  FIG. 11 shows an example of a SIP message (INVITE).

  The SIP server 5b receives the SIP message (INVITE) shown in FIG. 10 (114). Compared to the SIP message example before conversion shown in FIG. 9, FIG. 10 shows that the IP address set in the via header, Call-ID header, Contact header, and c parameters is converted from IPv6 to IPv4.

  The SIP server 5b specifies the location information of the receiving terminal 6b from the Start-Line destination information, and transmits the SIP message (INVITE) shown in FIG. 11 to the terminal 6b (115).

  If the terminal 6b allows INVITE, the terminal 6b responds with 200 OK. The voice information transmitted from the terminal 6b to the terminal 6a is transmitted to the IP address specified by the INVITE c parameter (the virtual IPv4 address “va4” of the terminal 6a) and the port number specified by the m parameter.

The SIP Response (200 OK) is transmitted to the terminal 6a via the SIP server on which the SIP Request has been processed based on the via header information.
FIG. 12 shows a SIP 200 OK message example 1.
FIG. 13 shows a SIP 200 OK message example 2.
Proceeding to FIG. 28, the SIP server 5b receives the SIP Response (200 OK) shown in FIG. 12 from the terminal 6b (121). The SIP server 5b transmits the SIP Response (200 OK) shown in FIG. 13 to the virtual IPv4 address “vsipa4” of the SIP server 5a (122). The address translator 1 detects the SIP message (200 OK) (123) and sends it to the SIP address translator 2 (124). The SIP address conversion device 2 that has received the SIP message activates a SIP message conversion processing routine 60. The flow of SIP message conversion processing (125 to 128) is the same as steps 108 to 111 in FIG. The SIP address translation device 2 transmits an address inquiry request in which “vsipa4, va4, b4” is set in the translation target IP address to the address translation device 1 (126). The address translation device 1 searches the translation information table 500 of the translation entry generation processing unit 12 using the translation target IP address, and detects the translation entries “vsipa4-sipa6” and “va4-a6” generated when receiving step 109. The address translation device 1 generates a virtual IPv6 address “vb6” for “b4” and stores it in the translation information table 500 of the translation information storage unit 16. The address translation device 1 transmits an address inquiry request response including a combination of the translation target IP address and the translated IP address to the SIP address translation device 2 (127).
FIG. 14 shows a SIP 200 OK message example 3.
FIG. 15 shows a SIP 200 OK message example 4.

  The SIP address translator 2 rewrites the IP address information and sends a SIP Response (200 OK) to the address translator 1 (128, 129). The address translation device 1 performs address translation of the IP packet header including SIP Response (130). Referring to the translation information table 500 of the translation information storage unit 16 of the address translation device 1, the destination address is the real IPv6 address “sipa6” of the SIP server 5a, and the source address is the virtual IPv6 address “vsipb6” of the SIP server 5b. Respectively. The address translation device 1 transmits a SIP Response (200 OK) shown in FIG. 14 to the SIP server 5a (131). The SIP server 5a transmits a SIP Response (200 OK) shown in FIG. 15 to the terminal 6a (132).

The voice information transmitted from the terminal 6a to the terminal 6b is transmitted to the IP address specified by the 200 OK c parameter (the virtual IPv4 address “vb6” of the terminal 6b) and the port number specified by the m parameter.
Proceeding to FIG. 29, when the terminal 6a receives the SIP Response (200 OK) for the INVITE, the terminal 6a transmits a response confirmation (ACK) to the SIP server 5a (141). The SIP server 5a sends a response confirmation (ACK) to the virtual IPv4 address “vsipb6” of the SIP server 5b (142). The address translation device 1 detects a SIP message (ACK) (143) and transmits it to the SIP address translation device 2 (144).

  The flow of SIP message conversion processing (145 to 148) is the same as steps 108 to 111 in FIG. The SIP address translator 2 sends a response confirmation (ACK) with the IP address information rewritten to the address translator 1 (149). The address translation device 1 translates the IP packet header address including the SIP message (ACK) (150). The address translation device 1 transmits an acknowledgment (ACK) to the real IPv4 address “sipb4” of the SIP server 5b (151). The SIP server 5b transmits a response confirmation (ACK) to the terminal 6b (152).

With the above procedure, a logical connection is set between the terminal 6a and the terminal 6b, and voice communication between the terminals becomes possible. The terminal 6a transmits a packet including voice information to the virtual IPv6 address (vb6) corresponding to the IPv4 address of the terminal 6b (153). The address translation device 1 searches the translation information storage unit 16 with the source IP address “a6” and the destination IP address “vb6”. Then, the conversion entry registered in step 109 and step 126 of the above processing sequence is detected.
The address translation device 1 rewrites the header information based on the translation entry (154). For the source IP address, a virtual IPv4 address “va4” corresponding to the IPv6 address “a6” of the terminal 6a is set. The actual IPv4 address “b4” of the terminal 6b is set as the destination IP address. The address translation device 1 transmits the packet obtained by converting the header information to the terminal 6b (155).
A packet including voice information transmitted from the terminal 6b to the terminal 6a is also subjected to the same processing (156 to 158).

  According to the present invention, the IP address of the SIP message can be converted using the information of the address conversion device. Therefore, SIP communication between terminals belonging to different areas becomes possible.

  A second embodiment of the present invention will be described with reference to the drawings.

  The first embodiment and the second embodiment differ in the function deployment method of the SIP message conversion means.

  In the second embodiment, the address translation device 1 has a function of detecting a translation target parameter of a SIP message.

  FIG. 20 shows a configuration example of the address translation device 1 in the second embodiment. The address translation device 1 in the second embodiment includes a tag processing unit 20 in the packet transfer control unit 13 in addition to the configuration example of FIG.

The tag processing unit 20 includes a conversion target parameter list 412 shown in FIG. 25 and a tag addition processing routine 80 shown in FIG. When the address translation device 1 detects the SIP message, it starts the tag assignment processing routine 80.
FIG. 22 shows a tag assignment processing routine 80 of the address translation device 1. The address translation device 1 compares the conversion target parameter list 412 with the received SIP message and extracts the conversion target parameters (81). When the conversion target parameter exists in the SIP message, the address conversion device 1 generates identification information (tag) and adds it to the detection parameter (82). The tag is composed of an address translation method and an identifier provided by the address translation device 1. The address translation device 1 transmits the SIP message to which the identification information is added to the SIP address translation device 2 (83), and ends this routine.
FIG. 21 shows a tagged SIP message example 410 transmitted from the address translation device 1 to the SIP address translation device 2. Compared to FIG. 8, it can be seen that a tag is added to the head of the line to be converted.
If the conversion target parameter does not exist in step 81, this routine is terminated.
When there is no conversion target parameter, the address conversion device converts the address information of the IP packet header including the received SIP message and transfers the SIP message. The content of the SIP message is not converted.

  In the second embodiment, the SIP address conversion device 2 includes a SIP message conversion processing routine 70 in the SIP message conversion processing unit 26.

  FIG. 23 shows a SIP message conversion processing routine 70 that is activated when the SIP address conversion device 2 receives a tagged SIP message in the second embodiment.

  The difference between the SIP message conversion processing routine 70 of FIG. 23 and the SIP message conversion processing routine 60 in the first embodiment is that a tag-added parameter extraction step 69 exists instead of step 61. In step 69, tagged parameters are extracted from the received SIP message.

  According to the embodiment of the present invention, the address translation device 1 has a SIP message translation target parameter detection function, so that the processing load on the SIP address translation device 2 can be reduced. If the received SIP message does not include the conversion target parameter, the address translation device 1 can transfer the SIP message without activating the SIP address translation device 2.

  A third embodiment of the present invention will be described with reference to the drawings.

The feature of this example is that the tag information in the second embodiment is associated with the call leg of SIP communication. Call leg indicates peer to peer SIP relationship.
Call leg can be uniquely identified by a combination of To header, From header, and Call-ID. The header is included in all SIP messages.
The address translation device 1 according to the present embodiment is similar to the address translation device 1 according to the second embodiment, further includes table information 300 for managing the correspondence between tags and call legs, and a table for managing the correspondence between tags and media information. Information 310 and method information indicating the start and end of the SIP session are provided. For example, BYE is a SIP method indicating a SIP session termination request.
Further, tag information is added to each entry of the conversion information table 500 included in the conversion entry generation processing unit 12 of the address conversion device 1.
In the present embodiment, the SIP address translation device 2 sets the tag information in the ID of the address inquiry request 600 transmitted to the address translation device 1. When the address translation device 1 generates a translation entry, the tag information is stored in the translation information table 500.
Normally, a SIP session termination request does not include a message-body. However, when providing finer SIP communication, it is desirable that the address translation device 1 deletes the address translation information of the corresponding session at the end of the session.
In the present embodiment, the address translation device 1 includes the correspondence information between the call leg and the tag, so that the corresponding translation information is deleted at the end of the session without the SIP address translation device 2 having a session state management function. Features.
FIG. 31 shows a tag management table 300 provided in the tag processing unit 20 of the address translation device 1 in this embodiment. Each entry in the tag management table 300 includes a tag (301), an IPv6 To header (302), an IPv6 From header (303), an IPv6 Call-ID (304), an IPv4 To header (305), an IPv4 From header (306), Define IPv4 Call-ID (307).
Since IP address information can be set in To header, From header and Call-ID header, entries on the IPv6 side and IPv4 side are defined.
FIG. 32 shows the media information management table 310 provided in the translation entry generation processing unit 12 of the address translation device 1 in this embodiment. Each entry of the media information management table 310 defines a tag (311), an IPv6 side c parameter (312), an IPv6 side m parameter (313), an IPv4 side c parameter (314), and an IPv4 side m parameter (315). The address translation device 1 includes the media information management table 310 to block the voice information after the session ends.

  FIG. 30 shows a tag assignment processing routine 90 provided in the address translation device 1 in the third embodiment. When detecting the SIP message, the address translator 1 searches the tag management table 300 (91). The search key is call leg information (To, From, Call-ID) of the received SIP message.

If no entry exists, a tag is generated (92).
The address translation device 1 refers to the method information indicating the start and end of the SIP session and the parameter list for translation 412 and performs processing according to the received message (93).

  If the SIP message indicates the end of the session and the conversion target parameter exists in the SIP message, the address translation device 1 transmits the SIP message with the tag information to the SIP address translation device 2 (94). The address translation device 1 receives the SIP message with the parameters rewritten from the SIP address translation device 2 (95). Here, the conversion entry of the corresponding tag included in the conversion information table 500 of the conversion entry generation processing unit 12 and the entry of the corresponding tag included in the media information management table 310 are deleted. Further, the conversion entry registration processing unit 11 requests the conversion information storage unit 16 to delete the corresponding entry. When the conversion entry registration processing unit 11 ends normally, this routine ends (96).

  If the SIP message indicates the end of the session and there is no conversion target parameter in the SIP message, the address translation device 1 executes step 96 described above.

  When the SIP message indicates the start of a session, the address translation device 1 registers the correspondence information of the tag, c parameter, and m parameter in the media information management table 310 (97). If the conversion target parameter exists in the SIP message, the address conversion device 1 transmits the SIP message with the tag information to the SIP address conversion device 2 (98), and this routine is finished. If the parameter to be converted does not exist in the SIP message, this routine ends.

  When the SIP message is other than the start end and the conversion target parameter exists in the SIP message, the address translation device 1 sends the SIP message with the tag information to the SIP address translation device 2 (98), and ends this routine. .

  If the SIP message is other than a session start / end request and the conversion target parameter does not exist in the SIP message, this routine ends.

  A case where the terminal 6a of the network A in the third embodiment performs voice communication using the SIP with the terminal 6b of the network B according to the sequence shown in FIGS. 33, 34, and 35 will be described.

33 and 34 show a session establishment sequence. The basic processing flow is the same as in FIGS.
The difference between FIG. 33 and FIG. 27 is that step 116 is added to FIG.
The difference between FIG. 34 and FIG. 28 is that step 133 is added to FIG.
In step 116 and step 133, the address translation device 1 identifies that the detected SIP message indicates session start, and associates the tag information with the correspondence information between the c parameter and the m parameter included in the detected SIP message in the media information management table. Store in 310.

  FIG. 35 shows a session end sequence. The basic flow is the same as in FIGS. The terminal 6a transmits a SIP message (BYE) requesting termination of the session with the terminal 6b to the SIP server 5a (161). The SIP server 5a transmits a SIP message (BYE) to the virtual IPv6 address “vsipb6” of the SIP server 5b (162). The address translator 1 detects this SIP message (BYE), and sends a tagged SIP message to the SIP address translator 2 (163, 164). The SIP message conversion process flow (165 to 168) is the same as steps 108 to 111 in FIG.

  When receiving the SIP message (BYE) in which the parameter including the IP address is rewritten from the SIP address converting device 2 (169), the address converting device 1 converts the address of the packet header including the SIP message (170). The address translation device 1 transmits a SIP message (BYE) to the real IPv4 address “sipb4” of the SIP server 5b (171). The SIP server 5b transmits a SIP message (BYE) to the terminal 6b (172).

  When the terminal 6b normally processes the BYE, the terminal 6b transmits a response 200 OK to the BYE to the SIP server 5b (173).

The SIP server 5b sends a response 200 OK to BYE to the virtual IPv4 address “vsipa4” of the SIP server 5a (174).
The address translation device 1 that has detected the SIP message detects that the received SIP message is a response to the end of the session (175), and sends the tagged SIP message to the SIP address translation device 2 (176). The SIP message conversion process flow (177 to 180) is the same as steps 108 to 111 in FIG.

When the address translator 1 receives the SIP message (BYE) whose parameters have been rewritten from the SIP address translator 2 (181), the address translator 1 translates the address of the packet header including the SIP message. Next, the address translation device 1 searches the tag management table 300 for a tag using call leg information of the SIP message as a search key. Next, the conversion entry of the corresponding tag included in the conversion information table 500 and the entry of the corresponding tag included in the media information management table 310 are deleted (182).
The address translation device 1 transmits a SIP message (BYE) to the terminal 6b via the SIP server 5b (183, 184).

  According to the embodiment of the present invention, the address translation device 1 has a correspondence relationship between a tag and a call leg, so that a translation entry can be deleted when SIP communication ends.

  A fourth embodiment of the present invention will be described with reference to the drawings.

  The present embodiment is characterized in that the IP address conversion device 1 includes SIP message conversion means.

  FIG. 24 shows a configuration example of the address translation device 1 in this embodiment.

  The packet transfer control unit 13 includes a SIP message conversion processing unit 31 and a conversion rule storage unit 32 in addition to the functional blocks of the address conversion device 1 in the first embodiment.

  The SIP message conversion processing unit 31 has a function provided in the SIP message conversion processing unit 26 of the SIP address conversion device 2 in the first embodiment.

  The conversion rule storage unit 32 has a function provided in the conversion rule storage unit 28 of the SIP address conversion device 2 in the first embodiment.

  According to the embodiment of the present invention, communication processing with the SIP address translation device 2 can be omitted by providing the address translation device 1 with SIP message translation means. Therefore, it is possible to increase the processing speed associated with SIP message conversion.

  A fifth embodiment will be described.

  In FIG. 1, network A7 uses an IPv4 private address. Network B8 uses IPv4 global addresses.

  The address translation device 1 has an IPv4 private address and IPv4 global address translation function instead of an IPv4 address and IPv6 address translation function.

  In this embodiment, the address translation device 1 that has received the SIP message from the IPv4 private network 7 transmits the SIP message to the SIP address translation device 2. The SIP address conversion device 2 refers to the conversion rule and identifies the conversion target IP address. For example, the translation target addresses are the IPv4 private address of the SIP server 5a and the IPv4 private address of the terminal 6a.

  The SIP address translation device 2 transmits an address inquiry request including the translation target IP address to the address translation device 1.

  The address translation device 1 that has received the address inquiry request creates a translation entry for the IPv4 private address and the IPv4 global address. The address translation device 1 transmits to the SIP address translation device 2 an address inquiry request response including the IPv4 private address before translation and the IPv4 global address after translation.

  According to the embodiment of the present invention, if the network A7 and the network B8 according to the IPv4 protocol are interconnected by the address translation device 1, and the SIP address translation device 2 rewrites the IP address included in the SIP message, it belongs to the network A7. Voice communication using SIP between the terminal and the terminal belonging to the network B8 becomes possible.

The block diagram which shows the structural example of the SIP communication network in this invention. 1 is a block diagram of an address translation device 1. FIG. The block diagram of the SIP address converter 2. FIG. IPv4 packet format diagram. IPv6 packet format diagram. SIP message format diagram. The protocol stack figure in this invention. The figure of SIP INVITE message example 1. The figure of SIP INVITE message example 2. The figure of SIP INVITE message example 3. The figure of SIP INVITE message example 4. The figure of SIP 200 OK message example 1. The figure of SIP 200 OK message example 2. The figure of SIP 200 OK message example 3. The figure of SIP 200 OK message example 4. The message format figure of an address inquiry request. The message format figure of an address inquiry request response. The SIP message conversion process routine figure with which the SIP address conversion apparatus 2 is provided. The conversion information table figure with which the address converter 1 is provided. The block diagram of the address translation apparatus 1 in the 2nd and 3rd Example of this invention. FIG. 9 is a diagram showing an example of a tagged SIP message in the second and third embodiments of the present invention. The tag addition process routine figure of the address translation apparatus 1 in 2nd Example of this invention. The SIP message conversion process routine figure of the SIP address conversion apparatus 2 in the 2nd and 3rd Example of this invention. The block diagram of the address translation apparatus 1 in the 4th Example of this invention. The SIP conversion object parameter list example figure in this invention. The SIP message conversion rule example figure in this invention. FIG. 1 is a SIP communication sequence diagram according to the present invention. FIG. 2 is a SIP communication sequence diagram according to the present invention. FIG. 3 is a SIP communication sequence in the present invention. The tag addition process routine figure of the address translation apparatus 1 in 3rd Example of this invention. The table figure of the tag management table in 3rd Example of this invention. The table figure of the media information management table in the 3rd Example of this invention. FIG. 1 is a SIP communication sequence diagram 1 according to a third embodiment of the present invention. FIG. 2 is a SIP communication sequence diagram 2 according to the third embodiment of the present invention. FIG. 3 is a SIP communication sequence diagram 3 according to the third embodiment of the present invention.

Explanation of symbols

1 Address translator, 2 SIP address translator, 3 DNS-ALG, 5 SIP server, 6 Terminal, 41 IP header, 42 TCP / UDP header, 43 Payload, 51 Source IPv4 address, 52 Destination IPv4 address, 53 IPv4 Payload, 54 source IPv6 address, 55 destination IPv6 address, 56 IPv6 payload, 60 SIP message conversion processing routine 1, 70 SIP message conversion processing routine 2, 80 tag addition processing routine 1, 90 tag addition processing routine 2.

Claims (5)

Address conversion device connected to the network in accordance with a different second network protocol with the network and the first network protocol according to a first network protocol, an address conversion system provided with a server device,
The address translation device
A conversion unit that converts an address included in the first area of the received communication data from an address according to the first network protocol to an address according to the second network protocol ;
Detecting means for detecting that the second region of the communication data follows a specific application protocol ;
If the to follow specific application protocol has been detected by said detecting means, the address included in the second region of the communication data, an address to follow from the address according to the first network protocol to the second network protocol Means for creating conversion information for conversion;
A transmission / reception unit that transmits the communication data and the conversion information to the server device, and receives the communication data in which the address included in the second area is converted based on the conversion information from the server device; ,
The server device is
Conversion that converts an address included in the second area of the communication data from an address according to the first network protocol to an address according to the second network protocol based on the conversion information received from the address conversion device. And
An address conversion system comprising: a transmission / reception unit that transmits the communication data in which the address included in the second area is converted to the address conversion device. The detection unit of the address translation device detects that the specific application protocol is complied with based on at least one of destination information included in the communication data and a port number. The address translation system described. 2. The address translation system according to claim 1, wherein the specific application protocol is SIP, the first area is an IP header, the second area is a payload, and is described according to the SIP. . 2. The address translation system according to claim 1, wherein the first network protocol is IPv4, and the second network protocol is IPv6. 2. The address translation system according to claim 1, wherein the first network protocol is IPv6 and the second network protocol is IPv4.

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