JP2001237879A - Terminal, repeater, communication method and recoding medium with recorded communication program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To start data communication from a terminal connected to a global network to a terminal connected to a private network. SOLUTION: A storage means 27 stores addresses of terminals 1-x (x=1, 2,..., n) connected to the private network 4 and a port number corresponding to the service provided by the terminal 1-x in advance. Upon the receipt of a packet to start data communication from a terminal 3 connected to the global network 5, an address conversion means 26 of a repeater 2 retrieves an address of a terminal registering a port number equal to a destination port number included in the packet from the storage means 27 and converts the destination address of the packet into the retrieved address and transmits the converted address to a network 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal device, a relay device, a communication method, and a recording medium on which a communication program is recorded, and more particularly to an address conversion method between a plurality of networks having different address systems.

[0002]

2. Description of the Related Art In recent years, "Internet Protocol-DARPA Inte
The spread of the Internet based on the IPv4 (Internet Protocol version 4) technology described in “rnet Program Protocol Specification, RFC791” is remarkable. Not only expansion of "Wireless A"
pplication Protocol Architectural Overview, WAP Ar
chitecture Version 30-Apr-1988 "
The mobile communication market has also been targeted, such as the emergence of a system using the AP (Wireless Application Protocol) technology.

In order to perform data communication by connecting a terminal device to the Internet, an address (IP address) for identifying the terminal device on the Internet is required. An IP address has a 32-bit address space, and an IP address (global address) assigned to a terminal device communicating on the Internet must be unique on the Internet. for that reason,
With the spread of the Internet and the accompanying increase in the number of terminal devices, the shortage of addresses assigned to the terminal devices has become a problem. Regarding the assignment of IP addresses, US IANA (Internet Assigned Numbers Auth
Ority), which is managed globally, and basically cannot be assigned to a terminal device by a user without permission.

In order to solve such a problem, in the long term, "Internet Protocol, Version 6 (IPv6) Specifica
Option, RFC2460 ”
Protocol version 6) The application of the technology has been decided,
In the current Internet, which has become widespread with the use of IPv4 technology, the actual solution until IPv6 becomes widespread is IPv4.
A technical solution is required.

[0005] As a conventional technology for solving this problem on the IPv4 technology, "The IP Network Address Translator (N
AT), RFC1631 ”
essTranslator) technology and "IP Network Address Transl
ator (NAT) Terminology and Considerations, RFC266
3) Network Address Port (NAPT)
Translator) technology.

[0006] These technologies are basically technologies for performing address conversion between one connected network and another connected network between two connected networks having different address systems, and are combined with the application of a private address. This realizes efficient use of addresses.

Here, the private address is "Ad
dress Allocation for Private Internets, RFC1918 ''
This is an IP address that can be used independently of IANA management. IP addresses "10.xxx", "172.16.xx", "192.1" as private addresses
68.xx "(where x represents an arbitrary value from 0 to 255). The IP address assigned to the private address is not used as a global address.

[0008] "The network Na and the network Nb have different address systems" means that the following condition is satisfied.

"Network Na and network Nb
Are networks that constitute a part of a certain meta-network (a collection of networks directly or indirectly connected to each other) (partial condition 1), and “the network Na and the network Nb are Each uses an address system based on assigning an identifier uniquely identifiable in the network as an address to a terminal device to be connected (partial condition 2), and “an arbitrary network connected to the network Na”. Regarding the terminal device T, “the value A of the address of the terminal device T does not make sense as an identifier representing an address in the address system of the network Nb (eg, is not used as an identifier representing an address) (partial condition 3-1)”; Or
"The value A of the address is meaningful as an identifier representing an address in the address system of the network Nb (used as an identifier representing the address), but the value A of the address is transmitted to the terminal device connected to the network Na in the network Nb. I do not know that I have assigned
(Partial condition 3-2) "(partial condition 3)".

For example, as shown in FIG. 25, a network N, a first network N1, and a second network N
2, the third network N3, the fourth network N4
There is a meta network connected as shown in FIG. 25,
The address system of each network is such that the network N is a global address (however, 133.xxx is not assigned for operation in the network N so that it can be used in the first network N1), and the first network N1 is a global address 133. .xxx, second network N2 is private address 10.xxx, third network N
3 adopts a private address, the fourth network N4 adopts a private address 10.255.xx,
Network N3 and fourth network N4 are 10.0.xx to 10.2 of one private address 10.xxx.
54.xx to the third network N3 and the remaining 10.255.x.
It is assumed that x is subnetted to the fourth network N4. Here, any two networks constituting FIG. 25 satisfy the partial condition 1 and the partial condition 2 among the above conditions.

Although both the global address system and the private address system use a part of the value of the 32-bit space as the address value, the global address system does not use the address value used in the private address system. ing. Therefore, in the network adopting the global address system and the network adopting the private address system, the above partial condition 3-1 is satisfied and the above condition is satisfied, so that the address systems are different. That is, the network N and the first network N1 have different address systems with respect to each of the second network N2, the third network N3, and the fourth network N4.

Further, since the condition 3 does not hold between the network N and the first network N1, the address systems do not differ. The second network N2 differs from the third network N3 and the fourth network N4 in the address system because the condition 3-1 is not satisfied but the condition 3-2 is satisfied. Since the third network N3 and the fourth network N4 do not satisfy the condition 3, the address systems do not differ.

FIG. 22 shows a configuration of an existing communication system to which the NAPT technology is applied.

As shown in FIG. 22, an existing communication system to which the NAPT technology is applied includes a terminal device T, a NAPT relay device R, a server device S, a global network Ng,
It is composed of a private network Np. The terminal device T accesses the server device S via the NAPT relay device R, and the terminal device T and the NAPT relay device R are connected by the private network Np. On the other hand, N
The APT relay device R and the server device S are connected by a global network Ng.

The global network Ng and the private network Np use different address systems. A global address is assigned to a terminal device connected to the global network Ng, and a private address is assigned to a terminal device connected to the private network Np. The terminal device T uses TCP / IP (Transmission Control Protocol).
/ Internet Protocol), an information processing device having a client program connected to the server program of the server apparatus S using the communication means and communicating with the server program. An address (referred to as Ap-t) is assigned.

The server device S has communication means by TCP / IP, waits for a connection from the client program of the terminal device T using the communication means, and stores information loaded with a server program for communicating with the connected client program. One global address (referred to as Ag-s) of the global network Ng is assigned by the processing device.

In the server S, the server program is waiting for a connection from the client program at the port identified by the port number Ps. The client program needs to know the port number Ps of the port, and when connecting to the server program, specifies the port number Ps as the port number of the destination port to the communication means. Connect to the server program and start a communication session with the server program.

The NAPT relay device R includes packet receiving means 1021, 1023, packet transmitting means 1022,
24, a router having an IP packet relay function, comprising an address conversion means 1025, 1026, and a storage means 1027. One private address (referred to as Ap-r) for the private network Np and the global network Ng Is assigned to one global address (referred to as Ag-r).

The storage unit 1027 holds a correspondence management table. FIG. 4 shows the configuration of the correspondence management table.

As shown in FIG. 4, the correspondence management table is
It has an entry consisting of an entry identifier field, a first socket field, a second socket field, and a third socket field. The entry identifier field stores the value of an entry identifier that uniquely identifies each entry of the correspondence management table in the NAPT relay device R. The first socket field consists of a pair of an address and a port number of the private network Np,
Each of the second socket field and the third socket field is composed of a set of an IP address and a port number of the global network Ng.

The packet receiving means 1021 receives an IP packet addressed to the global network Ng sent from the private network Np, and receives the received IP packet.
The packet is passed to the address conversion means 1025.

The packet transmitting means 1022 sends out the IP packet passed from the address translating means 1025 to the global network Ng.

The packet receiving means 1023 receives an IP packet addressed to the private network Np sent from the global network Ng, and receives the received IP packet.
The packet is passed to the address conversion means 1026.

The packet transmitting means 1024 sends out the IP packet passed from the address translating means 1026 to the private network Np.

As shown in FIG. 23, the address conversion means 1025 comprises a correspondence search means 1251, a packet conversion means 1252, and a registration means 1254.

The correspondence search means 1251 receives the IP passed from the packet reception means 1021 to the address conversion means 1025.
Receive the packet. Upon receiving the packet from the packet receiving unit 1021, the correspondence search unit 1251 determines that the value of the first socket field is equal to the set of the source address and the source port number of the IP packet from the correspondence management table of the storage unit 1027. In addition, an entry whose second socket field has the same value as the set of the destination address and the destination port number of the IP packet is searched.

When the entry is detected by the search, the correspondence search means 1251 passes the IP packet and the entry identifier stored in the entry identifier field of the entry to the packet conversion means 1252. If the entry is not detected by the search, the correspondence search unit 1251 passes the IP packet to the registration unit 1254.

Upon receiving the IP packet and the entry identifier, the packet conversion means 1252 sets the source address and the source port number of the IP packet in the third socket of the entry of the correspondence management table identified by the entry identifier. The IP address and the port number indicated in the field are rewritten to the values, and the rewritten IP packet is passed to the packet transmitting means 1022.

Upon receiving the IP packet, the registration means 1254 generates an unused entry identifier,
Choose an unused port number. And the registration means 12
Reference numeral 54 denotes the entry identifier as a value of an entry identifier field, and sets a set of a source address and a source port number, a set of a destination address and a destination port number of the IP packet in a first socket field and a second socket field, respectively. , And an entry in which the set of the IP address of the global network Ng of the NAPT relay device R and the selected port number is the value of the third socket field is created, and the entry is stored in the correspondence management table of the storage means 1027. Remember. Then, the registration unit 1254 stores the IP packet and the entry identifier in the packet conversion unit 1252.
Pass to.

As shown in FIG. 24, the address conversion means 1026 comprises a correspondence search means 1261 and a packet conversion means 1262.

The correspondence search unit 1261 receives the IP passed from the packet receiving unit 1023 to the address conversion unit 1026.
Receive the packet. Upon receiving the IP packet from the packet receiving unit 1023, the correspondence search unit 1261 determines from the correspondence management table of the storage unit 1027 that the value of the second socket field is the set of the source address and the source port number of the IP packet. A search is made for an entry that is equal and the value of the third socket field is equal to the set of the destination address and the destination port number of the IP packet.

When the entry is detected by the search, the correspondence search means 1261 passes the IP packet and the entry identifier stored in the entry identifier field of the entry to the packet conversion means 1262. If the entry is not detected by the search, the correspondence search unit 1261 discards the IP packet because the destination of the IP packet is unknown.

Upon receiving the IP packet and the entry identifier, the packet conversion means 1262 sets the destination address and the destination port number of the IP packet in the first socket indicated in the entry of the correspondence management table identified by the entry identifier. The IP packet and the port number are rewritten to the values of the IP address and the port number, and the rewritten IP packet is passed to the packet transmitting unit 1024.

Next, the operation of the NAPT technique will be described.

Here, first, in order for the terminal device T to start a communication session between the port Pt of the terminal device T and the port Ps of the server device S, the port P of the terminal device T is started.
The operation when the first IP packet (referred to as IP packet A) between −t and the port Ps of the server device S is transmitted to the private network Np will be described. At this time, the IP packet A has a destination address of the IP address Ag-s of the server device S, a source address of the IP address Ap-t of the terminal device T, and a destination port in the transport layer protocol header included in the IP packet A. The number is Ps, and the source port number is Pt.
It is also assumed that no entry is registered in the correspondence management table of the storage unit 1027 as an initial state.

The IP packet A addressed from the terminal device T to the server device S is received by the packet receiving means 1021 of the NAPT relay device R via the private network Np, and the packet receiving means 1021 converts the IP packet A into an address. Hand over to means 1025.

The IP packet A passed to the address conversion means 1025 is received by the correspondence search means 1251.
Upon receiving the IP packet A, the correspondence search unit 1251 searches the correspondence management table of the storage unit 1027 for the second
Is equal to the pair [Ap-t, Pt] of the source address and the source port number of the IP packet A, and the value of the third socket field is the IP address of the IP packet A.
A set of destination address and destination port number of packet A [Ag
-R, Pr].

In this case, since the entry does not exist in the correspondence management table, the entry is not detected by the search.

The correspondence search unit 261 passes the IP packet A to the registration unit 1254 because the entry is not detected in the search.

The registration means 1254 stores the IP packet A
, An unused entry identifier is generated, and one unused port number is selected in the NAPT relay device R (the selected port number is set to Pr). Then, the registration unit 1254 sets the entry identifier as the value of the entry identifier field, and sets the pair [Ap-t, Pt] of the source address and the source port number of the IP packet A.
And a set of destination address and destination port number [Ag-s, P
-S] as the values of the first socket field and the second socket field, respectively, and the set [Ag-r, Pr] of the IP address of the global network Ng of the NAPT relay device R and the selected port number. An entry for the value of the third socket field is created, and the entry is stored in the correspondence management table of the storage unit 1027. Then, the registration unit 1254 passes the IP packet A and the entry identifier to the packet conversion unit 1252.

Upon receiving the IP packet A and the entry identifier, the packet conversion means 1252 identifies the source address Ap-t and the source port number Pt of the IP packet A from the entry identifier, respectively. The IP address Ag-r and the port number Pr shown in the third socket field of the entry in the correspondence management table are rewritten to the values, and the rewritten IP packet (called IP packet B) is passed to the packet transmitting means 1022.

Upon receiving the IP packet B, the packet transmitting means 1022 sends the IP packet B to the global network Ng.

The above I sent from the NAPT repeater R
The P packet B is received by the server device S via the global network Ng. Based on the source address, source port number, destination address, and destination port number contained in the IP packet B, the server device S determines the port P of the device whose IP address is Ag-r.
-R and I between the port Ps of itself (server S)
If the packet is identified as a P packet and an IP packet is transmitted in the data communication session, the destination address of the IP packet is Ag-r, the destination port number is Pr, the source address is Ag-s, and the source is Set the port number to Ps.

Thereafter, when receiving the IP packet (referred to as IP packet C) of the communication session from the private network Np, the NAPT relay device R
The operation is the same as that of the packet A, except that
In the search process of 251, the correspondence search unit 1251
From the correspondence management table of the storage unit 1027, the value of the first socket field is equal to the pair [Ap-t, Pt] of the source address and the source port number of the IP packet C, and Is the set of the destination address and the destination port number of the IP packet C [Ag-
s, Ps], and finds an entry
The P packet C and the entry identifier of the detected entry are passed directly to the packet conversion unit 1252 without passing through the registration unit 1254. The processing after the packet conversion means 1252 is performed in the same manner as in the case of the IP packet A, and the IP packet C has the same source address Ag-r and source port number Pr as the IP packet B.
Is converted into a P packet (the converted IP packet is
(Referred to as a packet D) and sent to the server device S via the global network Ng as the converted IP packet D.

The IP packet (referred to as IP packet E) of the communication session transmitted from the server S after processing the IP packets A and B is
As described above, the destination address is Ag-r, the destination port number is Pr, the source address is Ag-s, the source port number is Ps, and the packet of the NAPT relay device R is transmitted via the global network Ng. Receiving means 1023
, And the packet receiving means 1023 passes the IP packet E to the address translating means 1026.

The IP packet E passed to the address conversion means 1026 is received by the correspondence search means 1261.
Upon receiving the IP packet E, the correspondence search unit 1261 searches the correspondence management table of the storage unit 1027 for the second
Is equal to the pair [Ag-s, Ps] of the source address and the source port number of the IP packet E, and the value of the third socket field is the IP
A set of the destination address and the destination port number of the packet E [Ag
-R, Pr].

In this case, the correspondence management table contains the above I
Since there is an entry registered at the time of processing the P packet A, and the entry corresponds to the entry to be searched, the correspondence search unit 1261 passes the IP packet E and the entry identifier of the entry to the packet conversion unit 1262.

When the IP packet E and the entry identifier are passed, the packet conversion means 1262 sends the destination address Ag-r and the destination port number P-P of the IP packet E.
r is the IP address A of the first socket of the entry of the correspondence management table identified from the entry identifier
It rewrites the values of pt and port number Pt, and passes the rewritten IP packet (referred to as IP packet F) to the packet transmitting means 1024.

When the IP packet F is passed, the packet transmitting means 1024 sends the IP packet F to the private network Np.

The above I sent from the NAPT repeater R
The P packet F is received by the terminal device T via the private network Np.

As described above, in the existing communication system to which the NAPT technology is applied, the socket composed of the set of the private address and the port number by the NAPT relay device R and the socket composed of the set of the global address and the port number A communication session identified by a pair of
One global address is associated with a set of port numbers, and the IP address of the private network Np is used for relaying.
The address and the port number, and the IP address and the port number of the global network Ng associated with the communication session are mutually converted, thereby connecting the device connected to the private network Np having a different address system and the global network Ng. IP communication between the devices is made possible. The present technology is also applicable to a communication system in which a plurality of private networks using the same private address system are connected to one global network. By connecting each private network and the global network with the NAPT relay device, communication between the terminal device connected to each private network and the server device connected to the global network can be realized. Therefore, by increasing the number of private networks connected by the NAPT relay device,
P addresses can be increased.

[0052]

A first problem is that when communication is performed between a server device connected to a global network and a terminal device connected to a private network, communication cannot be started from the server device. That is.

The reason is that when communication is started from the server device, the server device first needs to know the IP address of the terminal device from the name of the terminal device, but the address cannot be resolved at this time. is there.

A second problem is that communication cannot be performed between terminal devices connected to different private networks.

The reason is that, similarly to the reason of the first problem described above, the terminal which starts communication cannot resolve the address of the terminal which is the communication partner. An object of the present invention is to provide a terminal device, a relay device, a communication method, and the like that solve such problems.

[0056]

According to the present invention, a storage means 2 is provided.
7, a terminal device 1-x (x is connected in advance to the first network (the private network 4 in the example of FIG. 1).
= 1, 2,..., N) and a port number corresponding to the service provided by the terminal device 1-x are registered.
When the relay device 2 receives a packet for starting data communication from the terminal device 3 connected to the second network (the global network 5 in the example of FIG. 1) having an address system different from that of the first network, the relay device 2 converts the address to the address conversion means 26.
Searches the storage unit 27 for the address of the terminal device that has registered a port number equal to the destination port number included in the packet, converts the destination address of the packet into the searched address, and sends it to the first network. .

By adopting such a configuration, the second
When starting communication between a server device connected to the first network and a terminal device connected to the first network, communication from the server device can be started, and the terminal device connected to networks having different address systems The first and second problems can be solved by enabling communication between devices.

[0058]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a terminal device, a relay device,
And a first embodiment according to the communication method.

In the prior art, when a network having a global address system (global network) and a network having a private address system (private network) are connected by a relay device, one global address is assigned to one global address in the global network. And a plurality of terminal devices connected to the private network correspond to each other, and the first terminal device connected to the global network can uniquely identify the address of the second terminal device connected to the private network. Therefore, data communication from the first terminal device to the second terminal device could not be started. In the present embodiment, in addition to the configuration of the existing communication system, the storage unit (storage unit 1027) of the relay device
In this case, a processing terminal registration table is newly introduced as a table to be stored in the storage device, and a registration search unit and a registration unit are introduced into one of the address conversion units (corresponding to the address conversion unit 1026 in the existing technology). A service that enables data communication from the first terminal device to the second terminal device to be started is determined in advance, and a port number, which is one of service identifiers corresponding to the service, and the second terminal The correspondence with the address of the device is stored in the processing terminal registration table, and when the relay device receives a packet for starting a communication session from the first terminal device to the second terminal device, the registration search means The address of the second terminal device corresponding to the destination port number of the packet is searched from the processing terminal registration table, and the destination of the packet is set as the searched second terminal device. Data communication to the second terminal device can be started. Further, at this time, the registration means registers the correspondence of these sockets in the correspondence management table in the same manner as in the existing technology, so that it is possible to similarly relay bidirectional packets of the subsequent communication session. I do.

FIG. 1 shows the configuration of the first embodiment of the present invention.
This is shown in FIG. 2, FIG. 3, and FIG.

As shown in FIG. 1, a first embodiment of the present invention comprises a plurality of terminal devices (terminal device 1-1, terminal device 1-2,..., Terminal device 1-n), A relay device 2, a terminal device 3, and networks 4 and 5 are connected, and the terminal device 1 -x (x = 1, 2,..., N, and so on) and the relay device 2 are connected via the network 4. Then, the relay device 2 and the terminal device 3 are connected via the network 5.

The networks 4 and 5 are networks to which different address systems are applied.

The network 4 is a network configured by IP or other technologies, and is a network that provides a data transfer service such as an IP network, an ISDN network, and a mobile communication network. In Network 4,
A packet carrying user data and control information is transferred between the terminal device 1-x and the relay device 2.

The network 5 is an IP network to which a global address is applied. In Network 5,
An address resolution inquiry message for making an inquiry for address resolution between the relay device 2 and the terminal device 3, an address resolution response message for responding to the address resolution inquiry, and an IP packet carrying other control information and user data Is transferred.

The terminal device 1-x is an information processing device having a communication function that can be used on the network 4 and having a communication program for communicating with the communication program of the terminal device 3 using the communication function. And one address of the network 4 (referred to as A1-x). The terminal device name is FQDN (Fully Qualified Domain N
ame) format, it is composed of information on the network to which the terminal device is connected and an identifier that can be uniquely identified in the network, and other terminal devices, or programs or users of other terminal devices, Used to identify the terminal device.

The terminal device 3 is a terminal device used on the existing Internet, has a communication function by TCP / IP, and communicates with the communication program of the terminal device 1-x using the communication function. The terminal device name and one address of the network 5 (referred to as A2-1) are assigned to the information processing device equipped with. The terminal device name is composed of information of a network to which the terminal device is connected and an identifier that can be uniquely identified in the network like the FQDN format, like the terminal device 1-x, and other terminal devices, or This is used by a program of another terminal device or a user to identify the terminal device. When starting communication with another terminal device, the terminal device 3 uses the name of the other terminal device as the IP address of the other terminal device (or the destination of the IP packet to be sent to the other terminal device). Address resolution means for inquiring about the IP address of the device. The address resolution means is RFC
1035 "DOMAIN NAMES-IMPLEMENTATION AND SPECIF
ICATION "DNS (Domain Name System
m) Realized by technology.

The relay device 2 includes packet receiving means 21 and 2
3, packet transmission means 22, 24, address translation means 2
5, 26, storage means 27, address inquiry response means 28
And one address (A1) of the network 4
-R), and one IP address of the network 5 (A2-2).

The storage means 27 holds a processing terminal registration table and a correspondence management table. FIG. 4 shows the configurations of the processing terminal registration table and the correspondence management table.

As shown in FIG. 4, the processing terminal registration table stores an entry identifier field for storing a value of a first entry identifier for uniquely identifying an entry of the processing terminal registration table in the relay device 2, and an address of the network 4. An entry has a set of an address field to be stored and a port number field for storing a port number. In the processing terminal registration table, a terminal device for processing a service provided to the terminal device 3 is determined in advance, and the address of the terminal device for processing the service is set in an address field, and a port number corresponding to the service is set to a port number. The entry set in the field is stored. For example, the terminal device that provides the FTP service to the terminal device 3 is determined as the terminal device 1-1, and the address A1-1 of the terminal device 1-1 and the port number corresponding to the FTP service are stored in the processing terminal registration table. Twenty sets are set.

The correspondence management table has an entry including an entry identifier field, a first socket field, a second socket field, and a third socket field. The entry identifier field stores the value of the second entry identifier that uniquely identifies each entry of the correspondence management table in the relay device 2. The first socket field is composed of a set of an address and a port number of the network 4, and the second socket field and the third socket field are composed of a set of an IP address and a port number of the network 5.

The packet receiving means 21 is connected to the network 4
, And passes the received packet to the address conversion means 25.

The packet transmitting means 22 sends out the IP packet passed from the address translating means 25 to the network 5.

The packet receiving means 23 is connected to the network 5
Receives the IP packet destined for the network 4 sent from the network device, and converts the received IP packet into address conversion means 26.
Pass to.

The packet transmitting means 24 sends out the packet passed from the address translating means 26 to the network 4.

As shown in FIG. 2, the address conversion means 25 includes a correspondence search means 251 and a packet conversion means 25.
2. It is composed of registration means 254.

The correspondence search means 251 is the packet reception means 2
1 to the address conversion means 25. When the packet is passed from the packet receiving unit 21, the correspondence search unit 251 determines from the correspondence management table of the storage unit 27 that the value of the first socket field is equal to the set of the source address and the source port number of the packet, In addition, an entry whose value of the second socket field is equal to the pair of the destination address and the destination port number of the packet is searched.

When the entry is detected by the search, the correspondence search means 251 transfers the packet and the second entry identifier stored in the entry identifier field of the entry to the packet conversion means 252. If the entry is not detected by the search, the correspondence search unit 251 passes the packet to the registration unit 254.

When the packet and the second entry identifier are passed, the packet conversion means 252 converts the packet into an IP packet, and converts the source address and the source port number of the IP packet into the second entry identifier, respectively. The IP address and the port number shown in the third socket field of the entry of the correspondence management table identified from the above are rewritten to the value of the IP address and the port number, and the rewritten IP packet is passed to the packet transmitting means 22.

When the registration means 254 receives the packet, it generates an unused second entry identifier and selects one unused port number. Then, the registration means 254
Uses the second entry identifier as a value of an entry identifier field, and sets a set of a source address and a source port number, a set of a destination address and a destination port number of the packet in a first socket field and a second socket, respectively. An entry is created in which the set of the IP address of the network 5 of the relay device 2 and the selected port number is used as the value of the third socket field as the value of the field, and the entry is stored in the correspondence management table of the storage means 27. I do. Then, the registration unit 254 passes the packet and the second entry identifier to the packet conversion unit 252.

As shown in FIG. 3, the address conversion means 26 includes a correspondence search means 261 and a packet conversion means 26.
2. It is composed of registration search means 263 and registration means 264.

The correspondence search means 261 is the packet receiving means 2
3 receives the IP packet passed to the address conversion means 26. The correspondence search means 261 is provided by the packet reception means 23.
When the IP packet is passed from the storage device 27, the value of the second socket field is
P packet is equal to the pair of the source address and the source port number, and the value of the third socket field is the IP address.
Search for an entry that is equal to the pair of the destination address and destination port number of the packet.

When the entry is detected by the search, the correspondence search means 261 transfers the IP packet and the second entry identifier stored in the entry identifier field of the entry to the packet conversion means 262. If the entry is not detected by the search, the correspondence search unit 261 passes the IP packet to the registration search unit 263.

When the IP packet and the second entry identifier are passed, the packet conversion means 262 converts the IP packet into a packet of the network 4, and converts the destination address and the destination port number of the packet into the second entry, respectively. The IP address and port number of the first socket of the entry of the correspondence management table identified from the identifier are rewritten, and the rewritten packet is passed to the packet transmitting means 24.

Upon receiving the IP packet, the registration retrieving means 263 refers to the processing terminal registration table and retrieves an entry having the value of the destination port number of the IP packet as the value of the port number field.

If the search does not find the entry in the processing terminal registration table, the registration search means 263
Discards the IP packet and terminates the process.

When the entry is detected from the processing terminal registration table by the search, the registration search means 263 stores the first entry identifier stored in the entry identifier field of the entry and the IP packet in the registration means 26.
Pass to 4.

When the registration means 264 receives the first entry identifier and the IP packet, the registration means 264 stores the address stored in the address field of the entry of the processing terminal registration table of the storage means 27 identified by the first entry identifier. Read out the port number stored in the port number field, generate an unused second entry identifier, use the second entry identifier as the value of the entry identifier field, and set the address and the port number. Is the value of the first socket field, the set of the source address and the source port number of the IP packet is the second socket field, and the set of the destination address and the destination port number of the IP packet is a third socket field. Is created, and the entry is stored in the correspondence management table of the storage unit 27. Then, the registration unit 264 stores the IP packet and the second entry identifier in the packet conversion unit 2.
Pass to 62.

The address inquiry response resolution means 28 responds to the address resolution inquiry message sent from the network 5 by changing the name of the terminal device inquired by the address resolution inquiry message to the terminal device 1-x connected to the network 4. In the case of the name of the address resolution inquiry message, an address resolution response message having the IP address A2-2 of the network 5 assigned to the relay device 2 as a response to the address resolution inquiry message is transmitted to the sender of the address resolution inquiry message. .

Here, the structure of a message used in the present embodiment will be described with reference to FIG. Note that the structure of each message shown in FIG. 5 is schematically represented by extracting only fields related to the present invention.

The IP packet used in the network 5 includes a source address, a destination address, a source port number, a destination port number, various control information, and user data. FIG. 5A shows an example of the structure of the IP packet. Referring to FIG. 5A, an IP packet includes an IP header, a transport header, and a data part. As the transport header, any of a TCP header, a UDP header, and a header of another transport protocol may be used, and the header of any transport protocol is used is determined by a protocol identifier field of an IP header. Be instructed. In an IP packet, a source address and a destination address are included in an IP header, and a source port number and a destination port number are included in a transport header. Various control information and user data are included in the data section.

[0092] The address resolution inquiry message includes the name of the terminal device to be queried, and the address resolution response message includes the address of the terminal device having the name included in the responding address resolution inquiry message. FIG. 5 shows the structure of each message when address resolution is realized by the above DNS.
Shown in Referring to FIG. 5, the address resolution inquiry message and the address resolution response message both have an IP header and a transport header like the IP packet, but differ in that the data part in the IP packet is a DNS message. The difference between an IP packet and another message is that in the address resolution inquiry message and the address resolution request message, either the source port number or the destination port number is a value 5 representing the DNS service.
The IP packet is identified by the fact that the source port number and the destination port number are all other than 53. Further, the address resolution inquiry message and the address resolution response message are identified by the value of the inquiry / response flag in the DNS message (when the value of the inquiry / response flag is 0, the address resolution inquiry message is used. Is an address resolution response message).

The name of the terminal device to be queried for address resolution is stored in the name field in the DNS message of the address resolution inquiry message, and the address of the terminal device having the queried name is set to D in the address resolution response message.
It is stored in the address field in the NS message.

Each time the terminal device 3 creates an address solution inquiry message, the terminal device 3 generates an identifier that can be uniquely identified in the terminal device 3 and stores the identifier in the identifier field in the DNS message included in the created address solution inquiry message. Stores the generated identifier. When creating an address resolution response message in response to the received address resolution inquiry message, the relay device 2 extracts the identifier stored in the identifier field in the DNS message of the address resolution inquiry message, and The identifier is stored in the identifier field in the DNS message. Thereby, the terminal device 3
Can refer to the value of the identifier field in the DNS message of the received address inquiry response message to identify the address inquiry request message to which the address inquiry response message responds.

Packets used in the network 4 include a source address, a destination address, a source port number, a destination port number, various control information, and user data. If the network 4 is an IP network, the network 4 can be configured as shown in FIG. The configuration of the packet used in the network 4 depends on the type of the protocol technology used in the network 4 and cannot be uniquely expressed. For example, it can be expressed as shown in FIG.

Although not shown here, the terminal device 1-x, the relay device 2, and the terminal device 3 each receive all the messages, and check the message type information included in the message type field of each received message. There is provided a message distribution means for identifying the message type and passing the message type to a means for processing the message type. For example, the relay device 2 receives two types of messages, an IP packet and an address resolution inquiry message, from the network 5, and these messages are received by the message distribution unit of the relay device 2. If the received packet is a packet, the IP packet is passed to the packet receiving unit 23. If the received message is an address resolution inquiry message, the address resolution inquiry message is passed to the address inquiry response unit 28. Although such a message distribution means is necessary for carrying out the present invention, the message distribution means is not an essential component for realizing the technical features of the embodiment of the present invention, so that the description is simplified. In order to clarify the technical features of the embodiment of the present invention, illustration and description of the message sorting means are omitted.

Further, in other embodiments of the invention described below, the message distribution means is also required, but illustration and description of the message distribution means are omitted for the same reason.

Next, the operation of the first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, 4, and 6.

The data communication executed in the first embodiment of the present invention is a
2 where the x starts and the terminal 3 starts
There are types.

Since the data communication session is started by the terminal device 1-x in the same manner as the existing technology of the NAPT technology, the description of the operation is omitted, and here, the data communication session is started by the terminal device 3. The operation when the operation starts will be described.

In the network 4, the port number P1
The terminal device that processes the service corresponding to the terminal device 1-
x, and in the state where the correspondence between the address A1-x and the port number P1 is stored in the processing terminal registration table in the relay device, the terminal device 3 moves from the port of the port number P2 to the port number P1 of the terminal device 1-x. A case where data communication with a port is started will be described.

When the terminal device 3 starts data communication with the terminal device 1-x, first, address resolution is performed from the name of the terminal device 1-x. This is because the terminal device 3 is the terminal device 1-
The process is started by transmitting an address resolution inquiry message including the name of x as a resolution target device name to the network 5 (step A1 in FIG. 6).

The address resolution inquiry message is received by the address inquiry response means 28 of the relay device 2, and the address inquiry response means 28 determines that the device inquired by the address resolution inquiry message is the terminal device 1-x. From the relay device 2 in the network 5
It creates an address resolution response message using the P address A2-2 as a response to the inquiry, and transmits it to the network 5 (step A2).

[0104] The address resolution response message is received by the terminal device 3, and the terminal device 3 determines from the content of the address resolution response message that the destination IP address of the IP packet addressed to the terminal device 1-x is A2-2. Know.

Next, the terminal device 3 generates an IP packet including data addressed to the terminal device 1-x,
(Step A3). In the IP packet, the destination address is A2-2, the source address is A2-1, the destination port number is P1, and the source port number is P2.

The IP packet is sent to the packet receiving unit 23.
, And the packet receiving means 23 passes the IP packet to the address translating means 26.

The IP passed to the address conversion means 26
The packet is received by the correspondence search means 261. Upon receiving the IP packet, the correspondence search unit 261 sets the values of the second socket field and the third socket field from the correspondence management table of the storage unit 27 to the IP packet.
A pair of a source address and a source port number of a packet [A
2-1, P2] and an entry having a value equal to the set [A2-2, P1] of the destination address and the destination port number of the IP packet.

In this case, data communication between the port having the port number P2 of the terminal device 3 and the port having the port number P1 of the terminal device 1-x has not been performed in the past, and the entry does not exist in the correspondence management table. Therefore, the entry is not detected by the search.

The correspondence search means 261 passes the IP packet to the registration search means 263 because the entry was not detected in the search.

Upon receiving the IP packet, the registration search means 263 searches the processing terminal registration table for an entry having the destination port number value P1 of the IP packet as the value of the port number field.

In this case, as described above, the entry of the preset address A1-x and the port number P1 exists,
The entry is detected by the search.

Since the registration search means 263 detects the entry in the search, the registration search means 263 passes the first entry identifier stored in the entry identifier field of the entry and the IP packet to the registration means 264.

When the registration means 264 receives the first entry identifier and the IP packet, the registration means 264 stores the IP packet in the address field of the entry of the processing terminal registration table of the storage means 27 identified by the first entry identifier. Read out the port number stored in the address and port number fields, generate an unused second entry identifier, use the second entry identifier as the value of the entry identifier field, [A1-x, P1] as the value of the first socket field, and the set [A2-1, P2] of the source address and the source port number of the IP packet as the value of the second socket field, An entry in which a pair [A2-2, P1] of the destination address and the destination port number of the IP packet is used as the value of the third socket field Create and store the entry in the corresponding management table of the storage unit 27. Then, the registration unit 264 passes the IP packet and the second entry identifier to the packet conversion unit 262.

When the IP packet and the second entry identifier are passed, the packet converting means 262 receives the IP packet and the second entry identifier.
The packet is converted into a packet of the network 4, and the destination address and the destination port number of the packet are respectively set in the second
Is rewritten to the IP address and port number values A1-x and P1 indicated in the first socket field of the entry of the correspondence management table of the storage means 27 identified from the entry identifier of the storage means 27.
Pass to 4.

When the packet is passed, the packet transmitting means 24 sends the packet to the network 4, and the packet is received by the terminal device 1-x (step A4).

Thereafter, an IP packet transmitted from the terminal device 3 to the network 5 and addressed to the port number P1 of the terminal device 1-x (the destination address is A2-2 and the source address is A2
-1, destination port number is P1, source port number is P
2) is similarly received by the packet receiving means 23 of the relay device 2, and the IP packet is passed to the correspondence search means 261 by the packet receiving means 23, but the correspondence management table of the storage means 27 stores the second socket field in the correspondence management table. Is equal to the set [P2-1, P2] of the source address and the source port number of the IP packet, and the value of the third socket field is the set of the destination address and the destination port number of the IP packet [ P2-2, P1], the correspondence search unit 261 detects the entry by searching the correspondence management table, and converts the IP packet and the second entry identifier of the entry into the packet conversion unit 2.
62, the IP packet is converted by the packet converting means 262 into a packet of the network 4 addressed to the port number P1 of the terminal device 1-x, and the packet is transmitted by the packet transmitting means 24 via the network 4 to the terminal device 1
-Sent to x.

Similarly, after step A4, a packet addressed to the port number P2 of the terminal device 3 transmitted from the port number P1 of the terminal device 1-x to the network 4 (the destination address is A2-1, the source address is Is A1-x, the destination port number is P2, and the source port number is P1).
5. The destination address is A2 via the packet transmitting means 22.
-1, source address is A2-2, destination port number is P
2. The source port number is converted into an IP packet of P1, and the converted IP packet is transmitted to the terminal device 3 via the network 5.

As described above, when relaying an IP packet from the network 5 to the network 4, the relay device 2
Refers to the correspondence between the port number registered in advance and the address of the terminal device connected to the network 4 that processes the IP packet addressed to the port number, determines the terminal device to be the destination of the IP packet, By converting a packet to a packet addressed to the terminal device, communication from a terminal device of the network 5 to which the global address system is applied to a terminal device of the network 4 using a different address system becomes possible.

In the embodiment of the present invention, the network 5
Although the description has been given of the case where only one terminal device is connected to the network 5, the same can be applied to a case where a plurality of terminal devices are connected to the network 5.

Further, in the embodiment of the present invention, a terminal device (terminal device 1) connected to a network different from the global network (called a non-global network).
-X) and the communication between the terminal devices (terminal device 3) connected to the global network have been described. However, a plurality of non-global networks are different from each other in the relay device according to the embodiment of the present invention. The communication between any terminal devices connected to any non-global network is also realized in the communication system connected to. That is, in the communication system shown in FIG. 7, communication between arbitrary terminal devices is possible. This is because the terminal device (terminal device A) connected to the ith non-global network (where i is one of 1, 2,..., N) is connected to the j-th non-global network (where j is 1, 2,..., N and connected to j ≠ i) (terminal device B
), The operation of the i-th relay device with respect to the j-th relay device and the terminal device B is the same as that of the terminal device 3 in the embodiment of the present invention. It is because it becomes. However, when the relay network is a non-global network, the address system of the relay network must be different from any of the address system of the i-th non-global network and the address system of the j-th non-global network.

Further, in the embodiment of the present invention, a case has been described where the terminal device 1-x is a partner terminal device that knows the name when the terminal device 3 starts data communication. The device 3 may know only the name of the relay device 2 and perform the address resolution by designating the name of the relay device 2.

Next, a second embodiment of the present invention will be described with reference to FIG.

Referring to FIG. 8, according to a second embodiment of the present invention, a terminal device 1-x is different from terminal device 1-x in the first embodiment shown in FIG. Power supply operation monitoring means 11, registration request transmission means 12, deletion request transmission means 13, operation confirmation response means 14, storage means 15,
In addition, the relay apparatus 2 is different from the relay apparatus 2 in the first embodiment shown in FIG.
91, deletion request receiving means 292, operation check requesting means 29
3 is different. The configuration of the address translation unit 26 is the same as the configuration of the address translation unit 26 in the first embodiment shown in FIG.

The storage means 15 stores a provided service list.

The provided service list is a list including port numbers corresponding to the services provided by the terminal device 1-x to the terminal device 3, and is a list set in advance by the user of the terminal device 1-x. It is.

The power supply operation monitoring means 11 monitors the power supply operation of the terminal device 1-x by the user, and when the power supply ON operation is detected, notifies the registration request transmission means 12 of the power supply ON and the power supply OF
When the operation of F is detected, the power-off is notified to the deletion request transmitting means 13.

When notified of the power ON, the registration request transmitting means 12 refers to the provided service list in the storage means 15 and
A registration request message including a port number list including all the port numbers set in the provided service list and the address of the terminal device 1-x is created, and the registration request message is transmitted to the relay device 2 via the network 4. I do.

When notified of the power-off, the deletion request transmitting means 13 creates a deletion request message including the address of the terminal device 1-x, and transmits the deletion request message to the relay device 2 via the network 4. .

The operation confirmation response means 14
Receiving the operation confirmation request message transmitted from the relay device 2 via the relay device 2, and when the operation confirmation request message is received, creates an operation confirmation response message corresponding to the operation confirmation request message to the relay device 2; An operation confirmation response message is transmitted to the relay device 2 via the network 4.

The registration request receiving means 291 receives a registration request message transmitted from the terminal device 1-x via the network 4, and upon receiving the registration request message,
An unused first entry identifier is generated, the value of the entry identifier field is the first entry identifier, the value of the address field is the address included in the registration request message, and the value of the port number field is the registration number. It creates an entry which is a port number list included in the request message, stores the entry in the processing terminal registration table of the storage means 27, and notifies the operation confirmation request means 293 of the activation of the terminal device corresponding to the address. I do.

The deletion request receiving means 292 receives the deletion request message transmitted from the terminal device 1-x via the network 4, and upon receiving the deletion request message,
From the processing terminal registration table in the storage means 27, all entries whose address field value is equal to the address included in the deletion request message are deleted, and the operation confirmation request means 293 is notified of the end of the terminal device corresponding to the address. .

The operation confirmation request means 293 creates an operation confirmation request message, transmits the operation confirmation request message to the terminal device 1-x via the network 4, and transmits the operation confirmation request message from the terminal device 1-x. Wait for an operation confirmation response message to respond to. Thereafter, if the operation confirmation response message is successfully received, the operation confirmation requesting unit 293 confirms that the terminal device 1-x is operating. After that, if the operation confirmation response message fails to be received, the operation confirmation requesting means 293 sends the terminal device 1-
x is assumed to be stopped, and the value of the address field is set to the value of the terminal device 1 from the processing terminal registration table of the storage unit 27.
-Delete all entries equal to the address of x.

The operation confirmation requesting means 293 activates a timer immediately after transmission of the corresponding operation confirmation request message, and, upon expiration of the timer, receives the operation confirmation response message as a method of judging the reception failure of the operation confirmation response message. A failure method or the like can be used. In addition, the operation confirmation requesting unit 293 generates and transmits an operation confirmation request message to the terminal device 1-x, and transmits the operation confirmation request message to the terminal device 1-x after the start of the terminal device 1-x is notified.
Is repeated or until the operation confirmation response message from the terminal device 1-x fails to be received.

Next, the operation of the second embodiment of the present invention will be described with reference to FIG. 8, FIG. 9, and FIG.

The user of the terminal device 1-x turns on the power supply of the stopped terminal device 1-x (step B1 in FIG. 9).
Then, the power operation monitoring means 11 detects the operation of turning on the power, and notifies the registration request transmitting means 12 of the power ON.

The registration request transmitting unit 12 refers to the provided service list in the storage unit 15 and registers the port number list including all the port numbers set in the provided service list and the registration including the address of the terminal device 1-x. A request message is created, and the registration request message is sent to the network 4
(Step B2).

The registration request message transmitted to the relay device 2 is received by the registration request receiving means 291, and the registration request receiving means 291 generates an unused first entry identifier. From the included port number list and address, create an entry in which the value of the entry identifier field is the first entry identifier, the value of the address field is the address, and the value of the port number field is the port number list; The entry is stored in the processing terminal registration table of the storage means 27, and further, the operation confirmation request means 293 is transmitted to the terminal device 1-.
Notify the start of x.

At this point, the relay device 2 can relay the start of data communication from the terminal device 3 to the registered port number of the terminal device 1-x.

When notified of the activation of the terminal device 1-x, the operation confirmation request means 293 starts a confirmation operation to the terminal device 1-x (step B3). That is, the operation check request unit 293 creates an operation check request message,
The operation confirmation request message is transmitted to the terminal device 1-x via the network 4 (step B4).

The operation confirmation request message is sent to the terminal 1
The operation confirmation response unit 14 receives the operation confirmation response message from the relay device 2 via the network 4 and creates an operation confirmation response message in response to the operation confirmation request message. (Step B5).

The operation confirmation response message is received by the operation confirmation requesting means 293,
3 confirms that the terminal device 1-x is operating by receiving the operation confirmation response message (step B).
6).

Thereafter, the operation confirmation requesting means 293 continues to confirm that the terminal device 1-x is operating by periodically executing the above steps B4 to B6.

Thereafter, when the user of the terminal device 1-x turns off the power of the terminal device 1-x (step B7), the power supply operation monitoring means 11 detects the operation of turning off the power supply, and OFF is notified to the deletion request transmission means 13.

[0144] The deletion request transmitting means 13 is a terminal device 1-x
Then, a deletion request message including the address is created, and the deletion request message is transmitted to the relay device 2 via the network 4 (step B8).

The deletion request message transmitted to the relay device 2 is received by the deletion request receiving means 292, and the deletion request receiving means 292 reads the address field value from the processing terminal registration table of the storage device 27, and And deletes all entries equal to the address included in the terminal device 1-x and notifies the operation confirmation requesting means 293 of the end of the terminal device 1-x.

The operation confirmation requesting means 293 is provided for the terminal device 1-.
When the end of x is notified, the transmission of the operation check request message to the terminal device 1-x, which has been performed periodically, is stopped, and the check operation to the terminal device 1-x is ended (step B9). .

Further, during execution of the confirmation operation to the terminal device 1-x, the operation confirmation request means 293 always waits for reception of an operation confirmation response message which is a response to the operation confirmation request message immediately after transmission of the operation confirmation request message. The relay device 2 starts the operation of the terminal device 1-x when the normal operation of the terminal device 1-x is stopped due to a malfunction or abnormal stop of the control system of the terminal device 1-x. Used to detect outages. That is, the terminal device 1-
When the normal operation of x stops (step C1 in FIG. 10)
In the confirmation operation performed by the operation confirmation request unit 293, the operation confirmation request unit 293 transmits an operation confirmation request message (step C2) and starts a timer (step C3). The timer expires without receiving an operation confirmation response message (step C4). At this time, the operation check request unit 293 detects that the operation of the terminal device 1-x has stopped (step C5), and the value of the address field is changed from the processing terminal registration table of the storage unit 27 to the terminal device 1-x.
All entries equal to the address of x are deleted, and the confirmation operation to the terminal device 1-x ends (step C6).

When receiving an IP packet from the network 5, the relay device 2 operates in the same manner as in the above-described first embodiment of the present invention.

As described above, in the present embodiment, the provided service list set in the terminal device 1-x is registered in the relay device 2 when the terminal device 1-x is activated, and is relayed when the terminal device 1-x is terminated. Since the information is deleted from the device 2, information depending on the setting of the terminal device 1 -x can be automatically registered in the relay device 2, and the IP packet from the network 5 is transmitted to the terminal device 1 -x when the terminal device 1 -x operates. Device 1-x
However, when the terminal device 1-x is not operating, it becomes possible not to relay the IP packet from the network 5 to the terminal device 1-x.

In the present embodiment, the power supply of the terminal device 1-x is
At the time of ON, the port number set constituting the provided service list stored in the storage means 15 is notified to the relay device 2 and each port number of the port number set is stored in the processing terminal registration table of the storage means 27. This is the terminal device 1-
When “x” operates, the user changes the contents of the provided service list stored in the storage unit 15, and notifies the relay device 2 of the set of port numbers constituting the changed provided service list at that time. The value of the address field stored in the processing terminal registration table 27 is the terminal device 1-
It is also possible to delete all entries that are addresses of x and store each port number of the port number set in the processing terminal registration table of the storage unit 27.

Although the embodiment of the present invention has been described with respect to a case where one terminal device is connected to the network 5, the present invention can be similarly applied to a case where a plurality of terminal devices are connected to the network 5. it can.

Further, in the embodiment of the present invention, a terminal device (terminal device 1) connected to a network different from the global network (called a non-global network).
-X) and the communication between the terminal devices (terminal device 3) connected to the global network have been described. However, a plurality of non-global networks are different from each other in the relay device according to the embodiment of the present invention. The communication between any terminal devices connected to any non-global network is also realized in the communication system connected to. That is, in the communication system shown in FIG. 7, communication between arbitrary terminal devices is possible. This is because the terminal device (terminal device A) connected to the ith non-global network (where i is one of 1, 2,..., N) is connected to the j-th non-global network (where j is 1, 2,..., N and connected to j ≠ i) (terminal device B
), The operation of the i-th relay device with respect to the j-th relay device and the terminal device B is the same as that of the terminal device 3 in the embodiment of the present invention. It is because it becomes. However, when the relay network is a non-global network, the address system of the relay network must be different from any of the address system of the i-th non-global network and the address system of the j-th non-global network.

Further, in the embodiment of the present invention, the case where terminal device 1-x is the terminal device of the other party who knows the name when terminal device 3 starts data communication has been described. The device 3 may know only the name of the relay device 2 and perform the address resolution by designating the name of the relay device 2.

Next, a third embodiment of the present invention will be described with reference to FIGS.

Referring to FIG. 11, in a third embodiment of the present invention, a terminal device 1-x differs from the terminal device 1-x in the second embodiment shown in FIG. It has the capability information transmitting means 16 and the relay apparatus 2 has the capability information receiving means 294 in addition to the configuration of the relay apparatus 2 in the second embodiment shown in FIG. 8, and also see FIG. Then, the configuration of the address translation device 26 is different in that it has a destination selection unit 265 in addition to the configuration of the address translation device 26 in the first embodiment shown in FIG. Further, the processing capability information of the terminal device 1-x is stored in the storage unit 15, and a processing capability information field is added to the entry of the processing terminal registration table stored in the storage unit 27, as shown in FIG. .

Terminal device 1 stored in storage means 15
The -x processing capability information is information relating to the processing capability of the terminal device 1-x, and includes, for example, information relating to the processing capability of the CPU and the processing / display capability of various media such as text, audio, and images.

In the processing terminal registration table stored in the storage means 27, the configuration of the fields constituting the entry is the same as the field configuration in the first and second embodiments described above. Terminal device 1-x
Of the terminal device 1-x, the port number corresponding to the service provided by the terminal device 1-x, and the processing capability information of the terminal device 1-x. The point of management is different.

When notified of the power ON from the power operation monitoring means 11, the capability information transmitting means 16 reads the processing capability information of the terminal device 1-x stored in the storage means 15, and the processing capability information and the terminal A capability notification message including the address of the device 1-x is created, and the capability notification message is transmitted to the relay device 2.

The capability information receiving means 294 is connected to the terminal device 1-
x receives the capability notification message transmitted from the terminal device 1-x, the value of the address field being included in the capability notification message from the processing terminal registration table of the storage unit 27.
Then, a search is made for an entry equal to and the correspondence of the processing capability information included in the capability notification message is stored in the processing capability information field of the entry.

[0160] The destination selection means 265 is the registration search means 26.
When one or a plurality of first entry identifiers and one IP packet are notified from 3, the one or more first entry identifiers notified from the processing terminal registration table of the storage means 27 are used. Read the identified entry, further read the processing capability information of each terminal device from the read entry, compare the read processing capability information, select one optimal terminal device, the selected address and The registration unit 264 is notified of the set of port numbers and the IP packet.

As a method of selecting one terminal device from the processing capability information of a plurality of terminal devices, there is a method of selecting a terminal device having the highest processing capability.

Next, the operation of the third embodiment of the present invention will be described with reference to FIG.

The user of the terminal device 1-x turns on the power supply of the stopped terminal device 1-x (step D in FIG. 14).
1) and the power operation monitoring unit 11 sends the power ON to the registration request transmitting unit 12 in the same manner as the operation of the second embodiment described above.
And the registration request transmitting unit 12 transmits a registration request message including the address of the terminal device 1-x and a port number list corresponding to the service provided by the terminal device 1-x to the relay device 2 (step D2). The registration request receiving unit 291 of the relay device 2 receives the registration request message, creates an entry of the processing terminal registration table of the storage unit 27 including the port number list and the address included in the registration request message, and Is stored in the processing terminal registration table of the storage unit 27, and the operation check request unit 293 starts the operation check of the terminal device 1-x (step D).
3).

At the same time, the power supply operation monitoring means 11 of the terminal device 1-x also notifies the capability information transmission means 16 of the power ON.

When notified of the power ON, the capability information transmitting means 16 transmits the terminal device 1-1 stored in the storage means 15.
x, reads out the processing capability information, creates a capability notification message including the processing capability information and the address of the terminal device 1-x, and transmits the capability notification message to the relay device 2 (step D4).

The capability notification message transmitted to the relay device 2 is received by the capability information receiving means 294. The capability information receiving means 294 stores the value of the address field from the processing terminal registration table of the storage means 27 into the capability notification message. An entry equal to the included terminal device 1-x is searched, and the processing capability information included in the capability notification message is stored in the processing capability information field of the entry.

Thereafter, the relay device 2 is connected to the network 5
Receiving the IP packet from the packet receiving unit 23, the packet receiving unit 23
Is similar to the operation of the first embodiment described above.
The packet is passed to the correspondence search means 261 and the correspondence search means 2
Similarly, the value of the second socket field and the value of the third socket field in the correspondence management table of the storage means 27 are respectively the set of the source address, the source port number, the destination address, and the destination of the IP packet. Search for an entry equal to the port number pair.

The correspondence search means 261 determines whether the entry is detected by the search or not.
Processing is performed in the same manner as the operation of the first embodiment described above.
In particular, when the entry is detected, the subsequent processing is the same as the operation of the above-described first embodiment, and the description is omitted here.

When the entry is not detected by the search, the registration search unit 263 determines whether the value of the port number field is equal to the value of the port number field from the processing terminal registration table of the storage unit 27, as in the operation of the first embodiment. An entry equal to the destination port number of the IP packet is searched. Here, when one or a plurality of entries are detected as a result of the search, all of the detected entries are identified by the first entry identifier and the IP address. The packet is passed to the destination selection means 265.

The destination selection means 265 reads the entry identified by the first entry identifier passed from the processing terminal registration table of the storage means 27, and further reads the processing capability information of each terminal device from the read entry. Then, the read processing capability information is compared, and one optimal terminal device is selected. For example, the contents of the processing terminal registration table are as shown in FIG.
3 and the destination port number of the IP packet is 1
0000, and the notified first entry identifier is 1
In the cases of and 2, the CPU processing capability of the terminal device 1-1 having the value "1" in the entry identifier field is superior to the CPU processing capability of the terminal device 1-2 having the value "2" in the entry identifier field. Therefore, the destination selection means 265
The terminal device 1-1 is selected, and the first entry identifier “1” and the IP packet are passed to the registration unit 264.

The processing from the transfer of the entry identifier and the IP packet to the registration unit 264 to the transmission of the packet to the terminal device 1-x is the same as the operation of the above-described first embodiment. The description of the subsequent operation is omitted.

The entry of the terminal device 1-x stored in the processing terminal registration table of the storage means 27 is stored when the power of the terminal device 1-x is turned off, or for some reason, the relay device 2 stores the terminal device 1-x. When communication with the
Similarly to the operation of the above-described second embodiment, deletion is performed by the deletion request receiving unit 292 or the operation confirmation requesting unit 293.

As described above, when the relay apparatus 2 receives an IP packet for starting data communication from the network 5,
A terminal device that provides a service corresponding to a port number equal to the destination port number of the IP packet is a plurality of relay devices 2
The terminal selection unit 265 selects one terminal device based on the processing capability information of the plurality of terminal devices even if the terminal device provides the service required by the IP packet. Terminal device can be selected.

The processing capability information of the terminal device 1-x is stored in the storage means 15 of the terminal device 1-x, and each time the power of the terminal device 1-x is turned on, the capability information transmitting means 16 is stored.
Notifies the relay device 2 of the processing capability information, the capability information receiving unit 294 registers the processing capability information in the processing terminal registration table of the storage unit 27, and the power of the terminal device 1-x is turned off. At this time, or when normal communication with the relay device 2 becomes impossible for some reason, the deletion request receiving means 292 or the operation confirmation requesting means 293 deletes the entry relating to the terminal device 1-x from the processing terminal registration table. Thus, when the terminal device 1-x is not operating, or when the relay device 2 cannot communicate with the terminal device 1-x, the IP packet for starting data communication received from the network 5 is transmitted to the terminal device 1-x. -Relaying to x can be avoided.

In the embodiment of the present invention, the network 5
Although the description has been given of the case where only one terminal device is connected to the network 5, the same can be applied to a case where a plurality of terminal devices are connected to the network 5.

Further, in the embodiment of the present invention, a terminal device (terminal device 1) connected to a network different from the global network (called a non-global network).
-X) and the communication between the terminal devices (terminal device 3) connected to the global network have been described. However, a plurality of non-global networks are different from each other in the relay device according to the embodiment of the present invention. The communication between any terminal devices connected to any non-global network is also realized in the communication system connected to. That is, in the communication system shown in FIG. 7, communication between arbitrary terminal devices is possible. This is because the terminal device (terminal device A) connected to the ith non-global network (where i is one of 1, 2,..., N) is connected to the j-th non-global network (where j is 1, 2,..., N and connected to j ≠ i) (terminal device B
), The operation of the i-th relay device with respect to the j-th relay device and the terminal device B is the same as that of the terminal device 3 in the embodiment of the present invention. It is because it becomes. However, when the relay network is a non-global network, the address system of the relay network must be different from any of the address system of the i-th non-global network and the address system of the j-th non-global network.

Further, in the embodiment of the present invention, the case where terminal device 1-x is the terminal device of the other party who knows the name when terminal device 3 starts data communication has been described. The device 3 may know only the name of the relay device 2 and perform the address resolution by designating the name of the relay device 2.

Next, a fourth embodiment of the present invention will be described with reference to FIG. 1, FIG. 15, FIG. 16, and FIG.

In the first embodiment of the present invention, it is assumed that the port number system in the network 4 is equal to the port number system in the network 5. On the other hand, in the present embodiment, an entry including a first port number field for storing the port number of the network 4 and a second port number field for storing the port number field of the network 5 in the storage means of the relay device. And a port table having the following table. The port table manages the correspondence between the port number of the network 4 and the port number of the network 5 corresponding to the same service. It is characterized by referring to the number field and referring to the second port number field as the port number on the network 5 side. As a result, even when the port number systems of the network 4 and the network 5 are different, the terminal device 1
-X and the terminal device 3 can communicate with each other.

The structure of the fourth embodiment of the present invention is the same as that of the first embodiment of the present invention shown in FIG. 1, except that the storage means 27 has a port table, 25 and the internal configuration of the address conversion means 26 are different.

FIG. 17 shows the configuration of the processing terminal registration table, the correspondence management table, and the port table which are the tables provided in the storage means 27 in the present embodiment.

As shown in FIG. 17, the configuration, use, and usage of the processing terminal registration table and the correspondence management table are the same as those of the processing terminal registration table and the correspondence management table in the first embodiment of the present invention. However, in the port number field of the processing terminal registration table, network 4
Are stored in the first socket field of the correspondence management table, the port number in the network 4, the port number shown in the second socket field, and the port number shown in the third socket field. The port number of the network 5 is stored in the number.

The port table has an entry consisting of a first port number field for storing the port number of the network 4 and a second port number field for storing the port number field of the network 5, and has a network corresponding to the same service. The correspondence between the port number of the network 4 and the port number of the network 5 is stored in advance. For example, if the port number corresponding to the FTP service is
Value 10 for network 4 and value 20 for network 5
Then, these correspondences are stored as shown in (3) of FIG.

Address conversion means 2 in the present embodiment
5 is shown in FIG.

As shown in FIG. 15, the address conversion means 25 includes the correspondence search means 2251 and the packet conversion means 2
252 and registration means 2254. In the first embodiment of the present invention, the correspondence search means 251 of the address conversion means 25 is changed to the correspondence search means 2251, the packet conversion means 252 is changed to the packet conversion means 2252, and the registration means 254 is changed to the registration means 2254. It is characterized by being.

The correspondence searching means 2251 receives the packet passed from the packet receiving means 21 to the address converting means 25. The correspondence search unit 2251 is a
When the packet is passed from the storage unit 27, first, the port table of the storage unit 27 is searched for an entry in which the value of the first port number field is equal to the value of the destination port number of the packet.

When the entry is not detected by the search, the correspondence search means 2251 discards the packet and ends the processing.

When the entry is detected by the search, the correspondence search means 2251 determines from the correspondence management table of the storage means 27 that the value of the first socket field is the set of the source address and the source port number of the packet. And the value of the second socket field is equal to the combination of the destination address of the packet and the value of the second port number field of the entry of the port table detected in the search of the port table. Search for.

When the entry is detected from the correspondence management table by the search, the correspondence search means 2251 converts the packet and the second entry identifier stored in the entry identifier field of the entry into the packet conversion means 2.
252. When the entry is not detected by the search, the correspondence search unit 2251 passes the packet to the registration unit 2254.

Upon receiving the packet and the second entry identifier, the packet conversion means 2252 converts the packet into an IP address.
The IP address and the port number are converted into a packet, and the source address and the source port number of the IP packet are respectively indicated in the third socket field of the entry of the correspondence management table identified from the second entry identifier. And further rewrites the destination address and the destination port number of the IP packet to the IP address and port number indicated in the second socket field of the entry,
The rewritten IP packet is passed to the packet transmitting means 22.

Upon receiving the packet, the registration means 2254 searches the port table for an entry having the destination port number of the packet as the value of the first port number field, and reads the corresponding second port number. , An unused second entry identifier, and selects one unused port number of the network 5. Then, the registration means 22
Reference numeral 54 designates the generated second entry identifier as a value of an entry identifier field, a set of a source address and a source port number of the packet as a value of a first socket field, a destination address of the packet and a search The set of the value of the second port number field of the entry of the port table detected by the above is set as the value of the second socket field, and the set of the IP address of the network 5 of the relay device 2 and the selected port number is set as the third set. An entry is created for the value of the socket field, and the entry is stored in the correspondence management table of the storage unit 27. Furthermore, a port table entry is created in which the source port number of the packet is set to the value of the first port number field, and the selected port number is set to the value of the second port number field. Register in the table. Then, the registration unit 2254 passes the packet and the second entry identifier to the packet conversion unit 2252.

Address conversion means 2 in the present embodiment
6 is shown in FIG. As shown in FIG. 16, the address conversion unit 26 includes a correspondence search unit 261, a packet conversion unit 2262, a registration search unit 2263, and a registration unit 2
H.264. The packet translation means 262 of the address translation means 26 according to the first embodiment of the present invention is replaced by the packet
No. 3 is changed to registration search means 2263, and similarly, registration means 264 is changed to registration means 2264.

Upon receiving the IP packet and the second entry identifier, the packet converting means 2262 stores
From the port table, the entry having the source port number of the IP packet in the second port number field is searched, and the value of the first port number field of the detected entry of the port table is read. Then, the packet conversion means 2262 converts the IP packet into the network 4
, And rewrite the destination address and the destination port number of the packet to the values of the IP address and port number of the first socket of the entry of the correspondence management table identified from the second entry identifier, respectively. The source port number of the packet is rewritten to the value of the first port number field of the entry of the port table read out, and the rewritten packet is transmitted to the packet transmitting means 2.
Pass to 4.

When the IP packet is passed, the registration search means 2263 searches the port table for an entry having the destination port number of the IP packet as the value of the second port number field.

If the entry is not detected from the port table by the search, the registration search means 2263
The IP packet is discarded, and the process ends.

If the entry is detected from the port table by the search, the registration search means 2263 further refers to the processing terminal registration table and sets the first entry of the detected entry of the port table as the value of the port number field. Search for an entry that has the value of the port number field.

If the search does not find the entry in the processing terminal registration table, the registration search means 226
No. 3 discards the IP packet and terminates the processing.

When the entry is detected from the processing terminal registration table by the search, the registration search unit 2263 stores the value of the first entry identifier stored in the entry identifier field of the entry and the IP packet in the registration unit 2264. Pass to.

Upon receiving the first entry identifier and the IP packet, the registration unit 2264 receives the address stored in the address field of the entry of the processing terminal registration table of the storage unit 27 identified by the first entry identifier. Read out the port number stored in the port number field, generate an unused second entry identifier, use the second entry identifier as the value of the entry identifier field, and set the address and the port number. Is the value of the first socket field, the set of the source address and the source port number of the IP packet is the second socket field, and the set of the destination address and the destination port number of the IP packet is a third socket field. Is created, and the entry is stored in the correspondence management table of the storage unit 27. Furthermore, the unused network 4
Port number and select the selected port number as the first
Then, an entry is created in the port table using the value of the port number field of the IP packet and the source port number of the IP packet as the value of the second port number field, and the entry of the port table is registered in the port table. Then, the registration unit 2264 passes the IP packet and the second entry identifier to the packet conversion unit 2262.

Next, the operation of the fourth embodiment of the present invention will be described.

There are two types of data communication executed in the fourth embodiment of the present invention: a case where the terminal device 1-x starts a communication session and a case where the terminal device 3 starts. In any case, it is assumed that the correspondence between the port number of the network 4 and the port number of the network 5 corresponding to the service used in the communication session to be started is registered in the port table in advance.

First, the operation when the terminal device 1-x starts a communication session will be described.

Here, the operation when the terminal device 1-x starts a communication session for using the service provided by the terminal device 3 in order to use the service provided by the terminal device 3 will be described. The port number in the network 4 is P4 and the port number in the network 5 is P2. In order to indicate this correspondence, the relay device 2 has a port table in which a value of the first port number field is P4 and a second port number field. It is assumed that an entry whose value is P2 is registered. The terminal device 1-
It is assumed that x uses the port with the port number P1.

The terminal device 1-x sends out the first packet (called a packet A) to use the above service. In the packet A, the destination address is A2-1, the destination port number is P4, the source address is A1-x, and the source port number is P1.

The packet A sent from the terminal device 1-x is received by the packet receiving means 21 of the relay device 2 via the network 4, and the packet receiving means 21 passes the packet A to the address converting means 25.

The packet A passed to the address conversion means 25 is received by the correspondence search means 2251.

The correspondence search means 2251 uses the packet A
Is passed, first, the port table of the storage means 27 is searched for an entry in which the value of the first port number field is equal to the value P4 of the destination port number of the packet.

In this case, since the entry exists in the port table, the entry is detected by the search.

The correspondence search means 2251 determines from the correspondence management table of the storage means 27 that the value of the first socket field is the set [A1-x, P1] of the source address and the source port number of the packet A. Equal and the value of the second socket field is the set of the destination address of the packet A and the value of the second port number field of the entry of the port table detected in the search of the port table [A2-1, P2 Find entries with a value equal to].

In this case, since the entry does not exist in the correspondence management table, the entry is not detected by the search.

[0211] Then, the correspondence search means 2251 passes the packet A to the registration means 2254.

Upon receiving the packet A, the registration means 2254 searches the port table for an entry having the destination port number P4 of the packet A as the value of the first port number field, and searches for an unused second entry. An identifier is generated, and one unused port number of the network 5 is selected (the selected port number of the network 5 is P5). Then, the registration unit 2254 uses the generated second entry identifier as the value of the entry identifier field,
A set of a source address and a source port number of the packet A
[A1-x, P1] is the value of the first socket field, and the set [A2-1, P2] of the destination address of the packet A and the value of the second port number field of the entry of the port table detected by the search. P2] is the value of the second socket field, and the IP
A pair of an address and the selected port number [A2-2, P5]
Is created as the value of the third socket field, and the entry is stored in the correspondence management table of the storage unit 27. Further, the source port number P of the packet A
A port table entry is created in which 1 is the value of the first port number field and the selected port number P5 is the value of the second port number field, and the entry is registered in the port table. Then, the registration means 2254
Passes the packet A and the second entry identifier to the packet conversion means 2252.

Upon receiving the packet A and the second entry identifier, the packet conversion means 2252 converts the packet A into an IP packet, and converts the source address and the source port number of the IP packet into IP address A indicated in the third socket field of the entry of the correspondence management table identified from the entry identifier of No. 2
2-2 and the value of the port number P5.
The destination address and destination port number of the P packet are rewritten to the IP address A2-1 and port number P2 indicated in the second socket field of the entry, and the rewritten I
The P packet (called the IP packet B) is passed to the packet transmitting means 22. At this time, in the IP packet B, the destination address is A2-1, the destination port number is P2, the source address is A2-2, and the source port number is P5.

The IP packet B passed to the packet transmitting means 22 is transmitted to the terminal device 3 via the network 5. Since the destination address of the IP packet B is A2-1, the destination port number is P2, the source address is A2-2, and the source port number is P5, in the terminal device 3, the communication session is set to the address A2-2. Is interpreted as a communication session between the port P5 of the terminal device and the port P2 of the own terminal device, and an IP packet transmitted from the terminal device 3 relating to the communication session has a destination address of A2-2 and a destination port number of P5. , The source address is
A2-1, the source port number is P2.

Thereafter, when receiving the packet of the communication session (referred to as packet C) from network 4, relay apparatus 2 operates in the same manner as the processing of packet A described above. In the search process, the correspondence search unit 2252 uses the correspondence management table of the storage unit 27 to determine that the value of the first socket field is the set of the source address and the source port number of the packet C [A1-x, P1], and the value of the second socket field is the combination of the destination address of the packet C and the value of the second port number field of the port table entry detected in the port table search.
An entry equal to [A2-1, P2] is detected. Then, the correspondence search unit 2251 passes the packet C and the second entry identifier stored in the entry identifier field of the entry to the packet conversion unit 2252 directly without passing through the registration unit 2254. The subsequent processing is performed in the same manner as in the case of the packet A. The packet C is the same as the source address A2-
2. It is converted into an IP packet having a source port number P5, a destination address A2-1, and a destination port number P2 (the converted IP packet is referred to as an IP packet D), and the network 5 is used as the converted IP packet D. Is sent to the terminal device 3 via the terminal device 3.

As described above, an IP packet (referred to as an IP packet E) of the communication session transmitted from the terminal device 3 after processing the packet A and the IP packet B has a destination address of A2-2, Destination port number is P
5, source address is A2-1, source port number is P
2 is received by the packet receiving means 23 of the relay device 2 via the network 5, and the packet receiving means 23 passes the IP packet E to the address translating means 26.

The above IP passed to the address conversion means 26
The packet E is received by the correspondence search means 261. The correspondence search unit 261 determines from the correspondence management table of the storage unit 27 that the value of the second socket field is the IP packet E
Of the source address and the source port number [A2-1,
P2] and the value of the third socket field is a set of the destination address and the destination port number of the IP packet.
Search for an entry equal to [A2-2, P5].

In this case, in the correspondence management table, there is an entry registered at the time of the packet A processing, and since the entry corresponds to the entry to be searched, the correspondence search means 261 determines the IP packet E and the entry of the entry. The identifier is passed to the packet conversion means 2262.

Upon receiving the IP packet E and the second entry identifier, the packet conversion means 2262 has the source port number P2 of the IP packet in the second port number field from the port table of the storage means 27. The entry is searched, and the value P4 of the first port number field of the detected entry of the port table is read. Then, the packet conversion means 2262 outputs the IP packet E
Is converted to a packet of the network 4, and the destination address and the destination port number of the packet are respectively associated with the IP address A1-x of the first socket and the port number of the first socket of the entry of the correspondence management table identified from the second entry identifier. The packet is rewritten to the value P1, the source port number of the packet is further rewritten to the read P4, and the rewritten packet (called packet F) is passed to the packet transmitting means 24.

[0220] The packet transmitting means 24
Is passed, the packet F is transmitted to the network 4, and the packet F is received by the terminal device 1-x.

Next, the operation when the terminal device 3 starts a communication session will be described.

Here, first, the terminal device 3 is
In order to use the service provided by -x, an operation for starting a communication session for using the service will be described. The port number in the network 4 corresponding to the service is P1, and the port number in the network 5 is P5. In order to indicate this correspondence, the relay device 2 registers an entry in the port table in which the value of the first port number field is P1 and the value of the second port number field is P5, and It is assumed that the correspondence between the address A1-x and the port number P1 is stored in the processing terminal registration table. It is also assumed that the terminal device 3 uses the port of the port number P2.

Before transmitting the first IP packet (referred to as an IP packet A) to use the above service, the terminal device 3 first transmits the terminal device 1 in the same manner as in the operation of the first embodiment of the present invention. Address resolution is performed from the name of -x, and it is known that the destination IP address of the IP packet addressed to the terminal device 1-x is A2-2, but the description is omitted here.

Next, the terminal device 3 transmits the IP packet A
Is sent. The IP packet A has a destination address of A2
-2, destination port number is P5, source address is A2-
1. The source port number is P2.

The IP packet A is received by the packet receiving means 23 of the relay device 2 via the network 5, and the packet receiving means 23 passes the IP packet A to the address translating means 26.

The above IP passed to the address conversion means 26
The packet A is received by the correspondence search means 261. Upon receiving the IP packet A, the correspondence search unit 261 sets the values of the second socket field and the third socket field from the correspondence management table of the storage unit 27 to the source address and the source address of the IP packet A, respectively. An entry having the same value as the set [A2-1, P2] of the port number and the set [A2-2, P5] of the destination address and the destination port number of the IP packet A is searched.

In this case, since the entry does not exist in the correspondence management table, the entry is not detected by the search.

The correspondence search means 261 passes the IP packet A to the registration search means 2263 since the entry was not detected in the search.

Upon receiving the IP packet A, the registration search means 2263 searches the port table for an entry having the destination port number P5 of the IP packet A as the value of the second port number field.

In this case, as described above, the entry in which the value of the first port number field is P1 and the value of the second port number field is P5 is registered in the port table, and the entry is detected.

Since the entry is detected from the port table by the search, the registration search means 2263 further refers to the processing terminal registration table and determines the value of the port number field as the value of the first entry of the detected port table entry. Is searched for an entry having the value P1 of the port number field.

Also in this case, as described above, the correspondence between the address A1-x and the port number P1 is stored in the processing terminal registration table, and the entry is detected.

Since the entry is detected from the processing terminal registration table by the search, the registration search means 2263
The value of the first entry identifier stored in the entry identifier field of the entry and the IP packet A are passed to the registration unit 2264.

When the registration means 2264 receives the first entry identifier and the IP packet A, it is stored in the address field of the entry of the processing terminal registration table in the storage means 27 identified by the first entry identifier. The address A1-x and the port number P1 stored in the port number field are read out, an unused second entry identifier is generated, and the second entry identifier is set as the value of the entry identifier field. The pair [A1-x, P1] of the address and the port number is used as the value of the first socket field, and the pair [A2-1, P2] of the source address and the source port number of the IP packet A is set to the second socket field. A pair [A2-2, P5] of the destination address and the destination port number of the IP packet is set as the value of the socket field and the third socket field Create an entry for the value, and registers the entry in the corresponding management table of the storage unit 27.
Further, one unused port number of the network 4 is selected (the selected port number is set as P4), the selected port number P4 is set as a value of a first port number field, and the IP packet A A port table entry is created with the source port number P2 as the value of the second port number field, and the port table entry is registered in the port table. Then, the registration means 2264 stores the I
The P packet A and the second entry identifier are passed to the packet conversion means 2262.

When the IP packet A and the second entry identifier are passed, the packet conversion means 2262 stores the source port number P2 of the IP packet A in the second port number field from the port table of the storage means 27. , And reads the value P4 of the first port number field of the detected entry of the port table. Then, the packet converting means 2262 converts the IP packet A into a packet of the network 4, and sets the destination address and the destination port number of the packet in the first of the entries of the correspondence management table identified by the second entry identifier. And rewrites the source port number of the packet to the read P4, and sends the rewritten packet (called packet B) to the packet transmitting means 24. hand over.

The packet transmitting means 24 transmits the packet B
Is passed, the packet B is sent out to the network 4, and the packet B is received by the terminal device 1-x. Since the destination address of the packet B is A1-x, the destination port number is P1, the source address is A2-1, and the source port number is P4, in the terminal device 1-x, the communication session is performed at the address A2- 1 is interpreted as a communication session between the port P4 of the first terminal device and the port P1 of the own terminal device, and a packet transmitted from the terminal device 1-x relating to the communication session has a destination address of A
2-1, destination port number is P4, source address is A
1-x, the source port number is P1.

When the relay apparatus 2 receives an IP packet (referred to as an IP packet C) of the communication session from the network 5, the relay apparatus 2 operates in the same manner as the processing of the IP packet A described above. In the management table search process, the correspondence search unit 261
From the correspondence management table of the storage means 27, the values of the second socket field and the third socket field are the pair [A2-1, P2] of the source address and the source port number of the IP packet C and the IP packet C, respectively. An entry having a value equal to the pair [A2-2, P5] of the destination address and the destination port number of C is detected. And the correspondence detecting means 2
61 passes the IP packet C and the second entry identifier stored in the entry identifier field of the entry directly to the packet conversion means 2262 without passing through the registration search means 2263 and the registration means 2264. Subsequent processing is performed in the same manner as in the case of the IP packet A. The IP packet C has the same source address A2-2, source port number P4, destination address A1-x, destination port A4 as the packet B. The packet is converted into a packet having the number P1 (the converted packet is referred to as a packet D), and sent as the converted packet D to the terminal device 1-x via the network 4.

After processing the IP packet A and the packet B, the packet (referred to as packet E) of the communication session transmitted from the terminal device 1-x has the destination address A2-1, The destination port number is P4,
The source address is A1-x and the source port number is P1. The packet is received by the packet receiving unit 21 of the relay device 2 via the network 4, and the packet receiving unit 21 passes the packet E to the address translating unit 25.

The packet E passed to the address conversion means 25 is received by the correspondence search means 2251. Upon receiving the packet E, the correspondence search means 2251 first receives
From the port table of the storage means 27, the value of the first port number field is the value P of the destination port number of the packet E.
Search for an entry equal to 4.

In this case, the port table contains the IP
Since the entry registered at the time of the packet A processing exists, and the entry corresponds to the entry to be searched, the correspondence search unit 2251 further determines from the correspondence management table of the storage unit 27 that the value of the first socket field is A set of source address and source port number of E [A1-
x, P1], and the value of the second socket field is the set of the destination address of the packet E and the value of the second port number field of the entry of the port table detected in the search of the port table [ A2-1,
P2].

In this case, the correspondence management table contains the I
Since the entry registered at the time of the processing of the P packet A exists and the entry corresponds to the entry to be searched, the correspondence search means 2251 stores the packet E and the second entry identifier stored in the entry identifier field of the entry in the packet. It is passed to conversion means 2252.

When the packet E and the second entry identifier are passed, the packet conversion means 2252 converts the packet E into an IP packet, and converts the source address and the source port number of the IP packet into the IP address, respectively. IP address A indicated in the third socket field of the entry of the correspondence management table identified from the entry identifier of No. 2
2-2 and the value of the port number P5.
The destination address and destination port number of the P packet are rewritten to the IP address A2-1 and port number P2 indicated in the second socket field of the entry, and the rewritten I
The P packet (called the IP packet F) is passed to the packet transmitting means 22.

Upon receiving the IP packet F, the packet transmitting means 22 transmits the IP packet F to the network 5.
, And the IP packet is received by the terminal device 3.

In the embodiment of the present invention, the network 5
Although the description has been given of the case where only one terminal device is connected to the network 5, the same can be applied to a case where a plurality of terminal devices are connected to the network 5.

In the embodiment of the present invention, a terminal device (terminal device 1) connected to a network different from the global network (called a non-global network)
-X) and the communication between the terminal devices (terminal device 3) connected to the global network have been described. However, a plurality of non-global networks are different from each other in the relay device according to the embodiment of the present invention. The communication between any terminal devices connected to any non-global network is also realized in the communication system connected to. That is, in the communication system shown in FIG. 7, communication between arbitrary terminal devices is possible. This is because the terminal device (terminal device A) connected to the ith non-global network (where i is one of 1, 2,..., N) is connected to the j-th non-global network (where j is 1, 2,..., N and connected to j ≠ i) (terminal device B
), The operation of the i-th relay device with respect to the j-th relay device and the terminal device B is the same as that of the terminal device 3 in the embodiment of the present invention. It is because it becomes. However, when the relay network is a non-global network, the address system of the relay network must be different from any of the address system of the i-th non-global network and the address system of the j-th non-global network.

In the embodiment of the present invention, a case has been described in which terminal device 1-x is the terminal device of the other party whose name is known when terminal device 3 starts data communication. The device 3 may know only the name of the relay device 2 and perform the address resolution by designating the name of the relay device 2.

In the fourth embodiment of the present invention, the storage means 27 has a port table, the address conversion means 25 and the address conversion means 25 are different from those of the first embodiment shown in FIG. Although the configuration in which the internal configuration of the conversion unit 26 is different has been described, the port table is provided in the storage unit 27 and the address conversion unit is similarly provided in the configurations of FIGS. 8 and 11 which are the second and third embodiments. 25, the internal configuration of the address conversion means 26 is different, and the correspondence search means 251 of the address conversion means 25 and the registration search means 263 of the address conversion means 26 search the port table after searching the processing terminal registration table. Can be applied.

Next, an embodiment of a medium in which a communication program of the present invention is recorded will be described. In the present embodiment, in the first, second, third and fourth embodiments of the present invention, the terminal device 1-x and the relay device 2 of the present invention each include a data processing device and a storage device, and further include a communication program. (Not particularly shown). This recording medium may be a magnetic disk, a semiconductor memory, a CD-ROM, or another recording medium.

A communication program for controlling the relay device 2 is as follows.
The information is read from the recording medium to the storage device of the relay device 2, and the processing unit registration table and the correspondence management table are stored in the storage unit 27. Further, in the embodiment of the medium corresponding to the third embodiment, a processing terminal registration table including the capability information is further stored. In the embodiment of the medium corresponding to the fourth embodiment, furthermore, A port table is stored.

The data processing device is provided with packet receiving means 21 and 23, packet transmitting means 22 and 24, address converting means 25 and 26, and address inquiry responding means 2.
8 is generated and its operation is controlled. Further, in the embodiment of the medium corresponding to the second embodiment, a registration request receiving unit 291, an operation check requesting unit 293, and a deletion request receiving unit 292 are further generated to correspond to the third embodiment. In the embodiment of the medium, the capability information receiving unit 294 is further provided.
And control their behavior.

The data processing apparatus executes the same processing as the communication processing described for the relay apparatus 2 in the first, second, third and fourth embodiments under the control of the above-mentioned communication program.

In the embodiment of the medium corresponding to the second embodiment, the communication program for controlling the terminal device 1-x is read from the recording medium to the terminal device 1-x, and the data processing device monitors the power supply operation. Means 11, registration request transmitting means 1
2. The operation confirmation response means 14 and the deletion request transmission means 13 are generated and their operations are controlled. In the embodiment of the medium corresponding to the third embodiment, the capability information transmitting means 16 is further generated and the operation thereof is controlled. In the embodiment of the medium corresponding to the second embodiment, the storage unit 1
5 stores the provided service list. In the embodiment of the medium corresponding to the third embodiment, the storage unit 1
5 further stores processing capacity information.

The data processing device controls the terminal device 1-2 in the second and third embodiments under the control of this communication program.
The same processing as the communication processing by x is executed.

[0254]

Next, a first embodiment of the present invention will be described with reference to the drawings. Such an example corresponds to the first embodiment of the present invention.

As shown in FIG. 18, in the present embodiment, the network 4 is constituted by an Ethernet network,
The IP network adopting the private address system (192.168.xxx.xxx) managed by the owner of the hernet network, the existing Internet adopting the global address system as the network 5 and the personal computer as the terminal device 1-x To
An ISDN router is provided as the relay device 2 and a terminal device used by an external user is provided as the terminal device 3. ISD
N router is ISP (Internet Service Pro) in ISDN network.
vider) connected to the network.

Network 4 and Network 4
A network system composed of devices connected to an Ethernet cable is connected to an Ethernet cable wired in a private house and directly to the Ethernet cable or to an Ethernet cable.
personal home network system consisting of personal computers connected via an ernet hub, or a small business SOHO constructed with a similar configuration
(Small Office Home Office)
It is possible. Here, FTP is added to the Ethernet.
(File Transfer Protocol) FTP service
A server program is installed, and the name is ftp. user
-A. isp1. ne. jp and the address is 192.16
8.0.2, a terminal device, and a program for sending and receiving e-mails. user-1.
isp1. ne. jp is connected to the terminal device.

The ISDN router has the name user-a.
isp1. ne. 192.168.0.1 as the address on the Ethernet side and the ISP
13 as the global address assigned from
Assume that 3.1.1.5 has been assigned.

Here, it is assumed that the FTP server provides an FTP service to the external user terminal device. In this case, the processing terminal registration table of the ISDN router includes FT.
The address of the P server and the port number 20 corresponding to the FTP service are registered in advance ((1) in FIG. 19). It is also assumed that no entry exists in the correspondence management table.

At this time, if the external user terminal has the port number 1
024 from the user-a. isp1. ne. j
It is assumed that data communication for using the FTP service to p is started.

The external user terminal device has user-a. i
sp1. ne. When an address resolution inquiry message is created from the jp name and the address resolution inquiry message is transmitted (step A1 in FIG. 6), the ISDN router device or the network server capable of resolving the address of the ISDN router device within the ISP becomes An address resolution response message that responds to the address resolution inquiry message is created, and the address resolution response message is transmitted to the external user terminal device (step A2). At this time, the address resolution response message contains information that the address of the ISDN router queried in the address resolution inquiry message is 133.1.1.5.

When the external user terminal receives the address resolution response message, the external user terminal sets the destination address to the address 133.
1.1.5, the destination port number is 20 corresponding to the FTP service, the source address is 208.192.0.1, which is the address of the external user terminal device,
An IP packet whose source port number is 1024 is created, and the IP packet is transmitted to the ISDN router.

When the ISDN router receives the IP packet, the IP packet is passed from the packet receiving unit 23 to the correspondence searching unit 261. Since there is no entry corresponding to the IP packet in the correspondence management table,
The IP packet is passed to the registration search means 263.

The registration / retrieval means 263 refers to the processing terminal registration table. Here, since there is an entry in the processing terminal registration table whose port number field is equal to 20 as the destination port number of the IP packet, The entry identifier 1 of the entry and the IP packet are passed to the registration means 264.

The registration means 264 registers the correspondence of the IP packet in the correspondence management table from the contents of the entry of the processing terminal registration table corresponding to the passed entry identifier and the contents of the passed IP packet (FIG. 19). (2)).

Thereafter, the ISDN router refers to the entry of the registered correspondence management table, and refers to the port number 20 of the FTP server and the port number 1024 of the external user terminal.
And relay the IP packet between them.

In the first embodiment, the network 4
Has been described above using Ethernet, the network 4 may be a network using another communication medium or communication protocol such as IEEE 1394 or wireless LAN.

The connection from the relay device 2 to the network 5 may be a dedicated line, and the relay device 2 may be an IP router having an interface device for accommodating the dedicated line.

Next, a second embodiment of the present invention will be described with reference to the drawings. This example corresponds to the fourth embodiment of the present invention.

As shown in FIG. 20, this embodiment uses “Bluetooth Specification version 1.
0A ”, a wireless network using the Bluetooth technology described in“ 0A ”, an IP network including the existing Internet and a mobile communication network as the network 5, a slave device using the Bluetooth technology as the terminal device 1-x.
A portable information device having a communication function as a relay device 2
TCP / IP communication function with IP network and B
A mobile phone terminal device having a communication function as a master in the Bluetooth technology and a protocol conversion function between these protocols and having a function of relaying communication between the network 4 and the network 5 is referred to as an external device as the terminal device 3. Is provided with a terminal device to be used by the user.

[0270] As the portable information equipment used as the terminal device 1-x, here, a camera, a video camera, and a notebook PC are taken as examples, and it is assumed that addresses 1, 2, and 3 in Bluetooth are respectively assigned. Also, the notebook PC interprets the FTP protocol and performs FT.
Equipped with an FTP server program for providing a P service and a storage device for storing files,
It is assumed that the device is an FTP server dedicated device that performs direct communication using the Bluetooth technology.

The mobile phone terminal has a name user-a. op1. co. jp has been assigned and the global address 133.1.1.5 of the network 5 has been assigned.

It is assumed that the port number of the network 4 corresponding to the FTP service is 10 and the port number of the network 5 is 20.

Here, it is assumed that the notebook PC provides an FTP service to the external user terminal device. In this case, the port table of the mobile phone device indicates the correspondence between the port number 10 of the network 4 and the port number 20 of the network 5 corresponding to the FTP service ((3) in FIG. 21). , Note P
The correspondence between the address 3 of C and the port number 10 of the network 4 corresponding to the FTP service is ((1) in FIG. 21).
It is registered in advance. It is also assumed that no entry exists in the correspondence management table.

At this time, if the external user terminal has the port number 1
024 from the user-a. op1. co. jp
It is assumed that data communication for using the FTP service is started.

The external user terminal device has user-a. o
p1. co. When an address resolution inquiry message is created from the name of jp and the address resolution inquiry message is transmitted (step A1 in FIG. 6), a network capable of resolving the address of the mobile terminal device in a mobile phone terminal or a mobile communication network. The server creates an address resolution response message in response to the address resolution inquiry message;
The address resolution response message is transmitted to the external user terminal device (step A2). At this time, the address of the mobile phone terminal inquired by the address resolution inquiry message is 133.
1.1.5 is included.

When the external user terminal device receives the address resolution response message, the external user terminal sets the destination address to the address 133.
1.1.5, the destination port number is 20 corresponding to the FTP service, the source address is 208.192.0.1, which is the address of the external user terminal device,
An IP packet whose source port number is 1024 is created, and the IP packet is transmitted to the mobile phone terminal.

When the portable telephone terminal receives the IP packet, the IP packet is passed from the packet receiving means 23 to the correspondence searching means 261. Since there is no entry corresponding to the IP packet in the correspondence management table, The IP packet is passed to registration search means 2263.

The registration search means 2263 knows that the port number of the network 4 corresponding to the destination port number 20 of the IP packet is 10 by searching the port table, and further searches the processing terminal registration table for the port number. Since the entry in which the address of the terminal device of the network 4 that provides the service of the number 10 is registered is detected, the registration search unit 2263 passes the IP packet and the entry identifier 1 of the entry to the registration unit 2264.

[0279] The registration means 2264 registers the correspondence of the IP packet in the correspondence management table from the contents of the entry of the processing terminal registration table corresponding to the passed entry identifier 1 and the contents of the passed IP packet (FIG. 2
1 (2)).

Thereafter, the portable telephone terminal refers to the entry of the registered correspondence management table, and communicates with the FTP server program of the notebook PC by Bluetooth and the TCP between the port number 1024 of the external user terminal device.
/ IP relays communication.

[0281]

A first effect is that data communication can be started from a terminal device connected to the global network to a terminal device connected to the private network.

The reason is that the correspondence between the address of the terminal device connected to the private network and the port number corresponding to the service provided by the terminal device is managed in the relay device connecting the global network and the private network, and the correspondence is managed. For reference, in order to convert and relay the destination of a packet for starting data communication from a terminal device connected to the global network, the relay device transmits one global signal to a plurality of terminal devices connected to the private network. This is because even when the addresses are associated, the terminal device that transfers the IP packet can be identified by the value of the destination port number included in the IP packet that starts data communication.

[0283] The second effect is that the address of the terminal device on the partner side can be resolved between terminal devices connected to different private networks. This enables data communication between terminal devices connected to different private networks.

The reason is the same as that of the first effect.

A third effect is that an IP packet for starting data communication is relayed only when a terminal device connected to a private network is operating. As a result, it is possible to prevent an IP packet having no receiving terminal device from being relayed unnecessarily.

[0286] The reason is that the terminal device connected to the private network registers the service to be provided to the relay device at the time of activation, and deletes the registered service at the time of termination.

A fourth effect is that when a terminal device connected to the private network cannot operate normally due to some abnormality, an IP packet for starting data communication is not relayed. As a result, it is possible to prevent the receiving terminal device from unnecessarily relaying an IP packet that is not operating normally.

The reason is that the relay device periodically checks whether or not the terminal device connected to the private network with which the service is registered is normally operating.

The fifth effect is, in particular, the first embodiment and the second embodiment.
As shown in the embodiment, in a situation where one user manages a private network, if there are a plurality of terminal devices connected to the private network and capable of providing the same service, the service is currently provided. Even if the terminal device performing the operation terminates the operation, it is possible to automatically communicate with another terminal device that can provide the service in response to a subsequent request for the service.

The reason is that, in the private network, the port number resource is shared between the terminal devices connected to the private network, and as described for the reasons for the third and fourth effects above. If the terminal device becomes inactive, the registration of the service provided by the terminal device is automatically deleted, so that even if the terminal device currently providing the service ends the operation, the relay device does not This is because the request for the service can be relayed to another terminal device that has registered the provision of the service.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a block diagram showing a partial configuration of the first embodiment of the present invention;

FIG. 3 is a block diagram showing a partial configuration of the first embodiment of the present invention;

FIG. 4 is a diagram showing a configuration of a table according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a structure of a message according to the first embodiment of the present invention.

FIG. 6 is a sequence diagram showing an operation of the first exemplary embodiment of the present invention.

FIG. 7 is a block diagram showing another configuration according to the embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 9 is a first sequence diagram showing an operation of the second exemplary embodiment of the present invention.

FIG. 10 shows a second example of the operation of the second exemplary embodiment of the present invention.
Sequence diagram of

FIG. 11 is a block diagram showing a configuration of a third embodiment of the present invention.

FIG. 12 is a block diagram showing a partial configuration according to a third embodiment of the present invention;

FIG. 13 is a diagram showing a configuration of a part of a table according to the third embodiment of the present invention;

FIG. 14 is a sequence diagram showing an operation according to the third embodiment of the present invention.

FIG. 15 is a block diagram showing a partial configuration according to a fourth embodiment of the present invention;

FIG. 16 is a block diagram showing a partial configuration of a fourth embodiment of the present invention.

FIG. 17 is a block diagram showing a configuration of a table according to the fourth embodiment of the present invention.

FIG. 18 is a block diagram showing a configuration of the first exemplary embodiment of the present invention.

FIG. 19 is a diagram showing contents of a table in the first embodiment of the present invention.

FIG. 20 is a block diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 21 is a diagram showing contents of a table according to the second embodiment of the present invention;

FIG. 22 is a block diagram showing a configuration of an existing technology.

FIG. 23 is a block diagram showing a partial configuration of an existing technology.

FIG. 24 is a block diagram showing a partial configuration of an existing technology.

FIG. 25 is a block diagram showing an example of an existing IP network configuration.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 mobile terminal 2 relay device 3 terminal device 4 network 5 network 6 power supply operation monitoring means 12 registration request transmission means 13 deletion request transmission means 14 operation confirmation response means 15 storage means 21 packet reception means 22 packet transmission means 23 packet reception means 24 packets Transmission means 25 Address conversion means 26 Address conversion means 27 Storage means 28 Address inquiry response means 251 Correspondence search means 252 Packet conversion means 254 Registration means 261 Correspondence search means 262 Packet conversion means 263 Registration search means 264 Registration means 265 Destination selection means 291 Registration Request receiving means 292 Deletion request receiving means 293 Operation confirmation requesting means 294 Capability information receiving means 1021 Packet receiving means 1022 Packet transmitting means 1023 Packet receiving means 1024 Packet Packet transmitting means 1025 address converting means 1026 address converting means 1027 storage means 1251 correspondence searching means 1252 packet converting means 1254 registration means 1261 correspondence searching means 1262 packet converting means 2251 correspondence searching means 2252 packet converting means 2254 registration means 2262 packet converting means 2263 Registration search means 2264 Registration means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Ono 5-7-1 Shiba, Minato-ku, Tokyo Inside NEC Corporation (72) Inventor Hikari Ebata 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation (72) Inventor Shuichi Shibata 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation (72) Inventor Masahiko Tsuki 5-7-1 Shiba, Minato-ku, Tokyo NEC F term in the stock company (reference) 5K030 HB19 HC01 HD02 HD09 5K033 AA09 CB09 CC01 DA05 DB18 EC04 5K034 AA20 DD03 EE10 EE13 FF11 HH63

Claims (41)

[Claims] 1. A first network and a second network having an address system different from that of the first network are connected via a relay device, and the relay device is connected to the first network. Storing, in a first management table, one or more first entries including an address of the first terminal device and a service identifier of a service provided by the first terminal device; A second terminal device connected to the network transmits a packet addressed to a certain service, and the relay device, upon receiving the packet,
Searching for a first entry having the same service identifier as the destination service identifier included in the packet from the management table of
And rewriting the entry to the address of the first terminal device and transmitting the packet to the first terminal device. 2. A first network and a second network having an address system different from that of the first network are connected via a relay device, and the relay device is connected to the first network. Storing in the first management table one or more first entries including the address of the first terminal device and the service identifier of the service provided by the first terminal device; A first socket, which is a set of an address of a first terminal connected to the first network and a service identifier of the first terminal, and an address of a second terminal connected to the second network A second socket, which is a set of a service identifier of the second terminal device, an address of the second network of the relay device, and a second network of the relay device. Including a third socket is set between the service identifier one or more second
A second management table for storing an entry of the second network is prepared, a second terminal device connected to the second network transmits a packet addressed to a certain service, and the relay device Upon receiving a packet from the second network,
The values of the second socket and the third socket from the second management table are the same as the pair of the source address and the source service identifier and the pair of the destination address and the destination service identifier of the packet, respectively. Searching for an entry, if the second entry is not detected, searching for a first entry having the same service identifier as a destination service identifier included in the packet from the first management table; A set of the address of the first terminal device of the entry and the service identifier of the first entry is a first socket; a set of the source address and the source service identifier of the packet is a second socket; A set of a destination address and a destination service identifier of the packet is a third socket, and the first socket, the second socket, 3 is stored in a second management table, and the destination address of the packet is rewritten to the address of the first terminal device of the detected first entry. A communication method comprising transmitting the packet to a terminal device. 3. The relay device, when the second entry is detected, rewrites a destination address of the packet to an address of the first socket of the detected second entry, and The communication method according to claim 2, wherein the packet is transmitted to a terminal device. 4. A first network, and a second network having an address system and a service identifier system different from the first network are connected via a relay device, wherein the relay device comprises: Storing in a first management table one or more first entries including an address of a first terminal device connected to the first network and a service identifier of a service provided by the first terminal device; A first socket, which is a set of an address of a first terminal device connected to the first network and a service identifier of the first terminal device, and a second socket connected to the second network. A second socket, which is a set of the address of the terminal device and the service identifier of the second terminal device, the address of the second network of the relay device, and the relay device. It is a set of a service identifier of the second network including a third socket one or more second
A second management table for storing entries of the same is prepared, and one or a plurality of service identifiers including a service identifier used in the first network and a service identifier used in the second network for the same service are prepared. Is stored in a third management table, a second terminal device connected to the second network transmits a packet addressed to a certain service, and the relay device When a packet is received from the second network, the value of the second socket and the value of the third socket from the second management table are respectively set as the set of the source address and the source service identifier of the packet and the destination address. A search is made for a second entry that is the same as the pair with the destination service identifier. If the second entry is found, the previous entry is retrieved from the third management table. Searching for a third entry in which the value of the service identifier used in the second network is the same as the source service identifier of the packet, and searching the first entry of the third entry in which the source service identifier of the packet is detected; Rewriting the destination address and the destination service identifier of the packet with the address and service identifier of the first socket of the detected second entry, and transmitting the packet to the first terminal device; If the second entry is not detected, the third management table is searched for a third entry having the same service identifier value as the destination service identifier of the packet used in the second network, and is detected. The first management table using the service identifier of the first network in the third entry. A set of the first terminal device address of the detected and detected first entry and a service identifier of the entry is set as a first socket, and a set of a source address and a source service identifier of the packet is set as a first socket. A second entry including a first socket, the second socket, and the third socket as a second socket, wherein a set of a destination address and a destination service identifier of the packet is a third socket; Is stored in the second management table, a service identifier unused in the first network is selected, the selected service identifier is used as a service identifier of the first network, and a source service identifier of the packet is Creating the third entry as a service identifier of the second network, storing the third entry in the third management table, The destination address and the destination service identifier of the first entry are rewritten to the address and service identifier of the first terminal device of the detected first entry, and the source service identifier is rewritten to the selected service identifier. A communication method comprising transmitting the packet. 5. A first network, and a second network having a different address system and service identifier system from the first network are connected via a relay device, wherein the relay device comprises: Storing in a first management table one or more first entries including an address of a first terminal device connected to the first network and a service identifier of a service provided by the first terminal device; A first socket, which is a set of an address of a first terminal device connected to the first network and a service identifier of the first terminal device, and a second socket connected to the second network. A second socket, which is a set of the address of the terminal device and the service identifier of the second terminal device, the address of the second network of the relay device, and the relay device. It is a set of a service identifier of the second network including a third socket one or more second
A second management table for storing entries of the same is prepared, and one or a plurality of service identifiers including a service identifier used in the first network and a service identifier used in the second network for the same service are prepared. Is stored in a third management table, the first terminal device connected to the first network transmits a packet addressed to a certain service, and the relay device The third entry in which the value of the service identifier of the first network in the third management table is the destination service identifier of the packet is searched. If the third entry is detected, the third entry is searched from the second management table. The values of the first socket and the second socket are
Search for a second entry that is the same as the set of the source address and the source service identifier of the packet and the set of the destination address of the packet and the service identifier of the second network of the third entry searched for, respectively. When the second entry is detected, the destination service identifier of the packet is rewritten to the service identifier of the detected second socket, and the source address and the source service identifier of the packet are replaced with the third service identifier. Rewrites the packet with an address of a socket and a service identifier, transmits the packet to the second terminal device, and when the second entry is not detected, sets a set of a source address and a source service identifier of the packet to a first
And a combination of the destination address of the packet and the service identifier of the second network of the third entry detected by searching the third management table.
And a service identifier unused in the second network is selected, and a set of the address of the second network of the relay device and the service identifier of the selected second network is set as a third socket, A second entry including the first socket, the second socket, and the third socket is stored in the second management table, and the selected service identifier is stored in the second network. Creating the third entry with the source service identifier of the packet as the service identifier of the first network, storing the third entry in the third management table, and setting the destination service identifier of the packet as the The source address and the source service identifier are used as the service identifier of the second socket and the service address of the third socket. A communication identifier rewritten to a service identifier and transmitting the packet to the second terminal device. 6. A first network connected to the first network.
The terminal device notifies the relay device of a registration request including an address of the first terminal device and a service identifier of a service provided by the first terminal device. The relay device receives a pre-record request, The communication according to claim 1, wherein a first entry including an address of a terminal device and a service identifier included in the registration request is stored in the first management table. Method. 7. A first network connected to the first network.
The terminal device notifies the relay device of a deletion request including the address of the terminal device. When the relay device receives the deletion request, the relay device of the terminal device included in the deletion request from the first management table. Searching for a first entry having an address, and searching for a first entry found by the search.
3. The method according to claim 1, wherein the entry is deleted.
7. The communication method according to 3, 4, or 6. 8. The relay device transmits an operation confirmation request message to a first terminal device connected to the first network, and the first terminal device transmits the operation confirmation request message to the first terminal device. Upon receiving, the relay device transmits an operation confirmation response message to the relay device. The relay device confirms the operation of the first terminal device by receiving the operation confirmation response message, and operates the first terminal device. Is not confirmed, the first management table is searched for a first entry having the address of the first terminal device that has transmitted the operation confirmation request message, and the first entry detected by the search is retrieved. 8. The communication method according to claim 1, wherein the communication method is deleted. 9. The method according to claim 1, wherein one or a plurality of first entries of said first management table include processing capability information of a first terminal device connected to said first network. Item 9. The communication method according to item 1, 2, 3, 4, 6, 7, or 8. 10. A first terminal device connected to the first network notifies a capability notification message including an address of the terminal device and processing capability information to the relay device, wherein the relay device: The method according to claim 1, wherein upon receiving the capability notification message, processing capability information included in the capability notification message is stored in a first entry of the first terminal device in the first management table. ,
The communication method according to 3, 4, 6, 7, 8, or 9. 11. The relay device according to claim 1, wherein the relay device has a first service identifier that is the same as the destination service identifier included in the packet.
11. The communication method according to claim 9, wherein when a plurality of entries are detected, the first entry is determined based on the processing capability information. 12. 12. A relay device for connecting a first network to a second network having an address system different from that of the first network, the relay device comprising: an address of a first terminal device connected to the first network; A first management table storing one or more first entries including a service identifier of a service provided by the first terminal device, and a second terminal connected to the second network. First search means for searching a first entry having the same service identifier as a destination service identifier included in the packet from the first management table for a packet addressed to a service from the device; Means for rewriting the destination address to the address of the first terminal device of the first entry detected by the first search means. Relay apparatus characterized by being. 13. A relay device for connecting a first network to a second network having an address system different from that of the first network, wherein an address of a first terminal device connected to the first network is provided. A first management table storing one or more first entries including a service identifier of a service provided by the first terminal device; and a first terminal connected to the first network. A first socket, which is a set of an address of the device and a service identifier of the first terminal device, and an address of a second terminal device connected to the second network and a service identifier of the second terminal device. A second socket that is a set, an address of the second network of the relay device, and a service identifier of a service identifier of the second network of the relay device. A second management table storing one or a plurality of second entries including a socket of the second type, when a packet addressed to a certain service is received from a second terminal device connected to the second network. The values of the second socket and the third socket from the second management table are the same as the set of the source address and the source service identifier of the packet and the set of the destination address and the destination service identifier, respectively. The second to search for the second entry
And if the second entry is not detected by the search by the second search unit, the same service identifier as the destination service identifier included in the packet from the first management table for the packet. First search means for searching for a first entry possessed; a set of the address of the first terminal device of the first entry detected by the first search means and a service identifier of the first entry Is a first socket, a set of a source address and a source service identifier of the packet is a second socket, and a set of a destination address and the destination service identifier of the packet is a third socket. A first registration method for registering a second entry including the first socket, the second socket, and the third socket in the second management table; When the relay apparatus characterized by being configured to include a means for rewriting the destination address of the packet to the first address of the terminal device of the first entry detected by the first search means. 14. A means for rewriting a destination address of said packet to an address of said first socket of said detected second entry when a second entry is detected by said second search means. 14. The relay device according to claim 13, comprising: 15. A relay device for connecting a first network and a second network having a different address system and service identifier system from the first network, comprising: a first network connected to the first network; A first management table that stores one or more first entries including an address of one terminal device and a service identifier of a service provided by the first terminal device; and a connection to the first network. A first socket, which is a set of the address of the first terminal device and the service identifier of the first terminal device, an address of a second terminal device connected to the second network, and the second socket. A second socket, which is a set of the service identifier of the terminal device, the address of the second network of the relay device, and the second network of the relay device. Including a third socket is set between the service identifier one or more second
A second management table that stores an entry of one or more third entries including a service identifier used in the first network and a service identifier used in the second network for the same service. When a packet addressed to a certain service is received from a second terminal device connected to the second network, a third socket and a third socket are stored from the second management table. Second search means for searching for a second entry whose socket value is the same as the set of the source address and the source service identifier of the packet and the set of the destination address and the destination service identifier of the packet; When the second entry is detected by the search means, the service used in the second network is read from the third management table. Third search means for searching for a third entry whose discriminator value is the same as the source service identifier of the packet; third entry detected by the third search means for the source service identifier of the packet Means for rewriting to the service identifier of the first network, and rewriting the destination address and destination service identifier of the packet to the address and service identifier of the first socket of the detected second entry; and the second search means When the second entry is not detected, a fourth entry is searched from the third management table for a third entry having the same service identifier value as the destination service identifier of the packet used in the second network. Search means; service of the first network of the third entry detected by the fourth search means A first search unit for searching the first management table by using an identifier, an address of the first terminal device of the first entry detected by the first search unit, and a service identifier of the entry A first socket, a set of a source address and a source service identifier of the packet as a second socket, a set of a destination address and a destination service identifier of the packet as a third socket, A second entry including the first socket, the second socket, and the third socket is registered in the second management table, and further, a service identifier unused in the first network is registered. Selecting the selected service identifier into the first
Registering means for creating the third entry with the service identifier of the packet as the service identifier of the network and the service identifier of the packet as the service identifier of the second network, and registering the third entry in the third management table; Means for rewriting the destination address and the destination service identifier to the address and service identifier of the first terminal device of the detected first entry, and means for rewriting the source service identifier to the selected service identifier. A relay device. 16. A relay device for connecting a first network and a second network having a different address system and service identifier system from the first network, comprising: a first network connected to the first network; A first management table that stores one or more first entries including an address of one terminal device and a service identifier of a service provided by the first terminal device; and a connection to the first network. A first socket, which is a set of the address of the first terminal device and the service identifier of the first terminal device, an address of a second terminal device connected to the second network, and the second socket. A second socket, which is a set of the service identifier of the terminal device, the address of the second network of the relay device, and the second network of the relay device. Including a third socket is set between the service identifier one or more second
A second management table that stores an entry of one or more third entries including a service identifier used in the first network and a service identifier used in the second network for the same service. A third management table to be stored; and a packet addressed to a certain service received from a first terminal device connected to the first network, wherein a service identifier of the first network in the third management table is stored. Third search means for searching for the third entry whose value is the destination service identifier of the packet; and if the third entry is detected by the third search means, from the second management table The value of the first socket and the value of the second socket are respectively a set of the source address and the source service identifier of the packet, and the value of the packet. Second third entry destination address of Tsu bets to have been the search
Second search means for searching for the same second entry as the set of the service identifier of the network, and when the second entry is detected by the second search means, the destination service identifier of the packet is set to the Rewrite with the service identifier of the detected second socket,
Means for rewriting the source address and the service identifier of the packet to the address and service identifier of the third socket; and the source address of the packet if the second entry is not detected by the second search means. And a source service identifier as a first socket, and a set of a destination address of the packet and a service identifier of a second network of a third entry detected by searching the third management table as a first socket. And a service identifier unused in the second network is selected, and a set of the address of the second network of the relay device and the service identifier of the selected second network is set as a third socket. A second entry including the first socket, the second socket, and the third socket, Registering the selected service identifier in the second management table as the service identifier of the second network, and setting the source service identifier of the packet to the first service identifier;
Registering means for creating the third entry as a service identifier of the network of the above, and registering the third entry in the third management table; a destination service identifier of the packet as a service identifier of the second socket; A relay device, comprising: means for rewriting a source service identifier to an address of the third socket and a service identifier. 17. Upon receiving a registration request including an address of the first terminal device and a service identifier from the first terminal device connected to the first network, the first terminal device included in the registration request Means for storing, in the first management table, a first entry including the address and the service identifier of the first terminal, upon receiving a deletion request including the address of the first terminal from the first terminal, Means for retrieving a first entry having an address of a first terminal device included in the deletion request and deleting the detected first entry from the first management table. Item 16. The relay device according to Item 12, 13, 14, or 15. 18. The first terminal device connected to the first network transmits an operation confirmation request message to the first terminal device, and receives the operation confirmation response message from the first terminal device. If the operation of the first terminal device is not confirmed, and the operation of the first terminal device cannot be confirmed, the first terminal device having the address of the first terminal device that transmitted the operation confirmation request message from the first management table.
18. The relay device according to claim 12, further comprising an operation check requesting unit that searches for the first entry and deletes the detected first entry. 19. The system according to claim 12, wherein the first entry of said first management table includes processing capability information of a first terminal device connected to said first network. , 14, 15, 17 or 18. 20. Upon receiving a capability notification message including an address of the terminal device and processing capability information from a first terminal device connected to the first network, the first management table includes 19. The apparatus according to claim 12, further comprising means for storing processing capability information included in the capability notification message in a first entry of one terminal device. Relay device. 21. When a plurality of first entries having the same service identifier as the destination service identifier included in the packet are detected, the first entry is determined based on the processing capability information. The relay device according to claim 19 or 20, wherein 22. A terminal device connected to a first network and a second network having an address system different from that of the first network via a relay device, and connected to the first network. And storing a first or a plurality of first entries including an address of a first terminal connected to the first network and a service identifier of a service provided by the first terminal. And a means for notifying the relay device having the management table of (1) of a registration request including an address of the terminal device and a service identifier of a service provided by the terminal device. 23. The terminal device according to claim 22, further comprising means for notifying the relay device of a deletion request including the address of the terminal device to the relay device. 24. The terminal device according to claim 22, further comprising means for transmitting an operation confirmation response message when receiving the operation confirmation request message from the relay device. 25. The terminal device according to claim 22, further comprising means for notifying said relay device of processing capability information of said terminal device. 26. A first network, and a second network having an address system different from that of the first network is connected via a relay device, and its own terminal device connected to the first network. And one or more first entries including a service identifier of a service provided by the terminal device of the terminal device are stored in a first management table of the relay device. For a packet addressed to a certain service from another terminal device connected to the second network, a first entry having the same service identifier as the destination service identifier included in the packet is searched from the first management table. The destination address of the packet is rewritten to the address of its own terminal device of the first entry detected by the search and transmitted. Terminal and wherein the receiving the packets. 27. A recording medium recording a communication program of a relay device for connecting a first network and a second network having a different address system from the first network, the recording medium being connected to the first network. A first management table storing one or more first entries including an address of the first terminal device and a service identifier of a service provided by the first terminal device; For a packet addressed to a service from a connected second terminal device, a first entry for searching a first entry having the same service identifier as a destination service identifier included in the packet from the first management table. Search means; and a destination address of the packet, the address of the first terminal device of the first entry detected by the first search means. Recording medium storing a communication program for causing a function to the relay device and a converting means for rewriting the. 28. A recording medium recording a communication program of a relay device for connecting a first network and a second network having a different address system from the first network, wherein the recording medium is connected to the first network. A first management table storing one or more first entries including the address of the first terminal device and a service identifier of a service provided by the first terminal device; and the first network. A first socket, which is a set of an address of a first terminal device connected to the first terminal device and a service identifier of the first terminal device; an address of a second terminal device connected to the second network; A second socket, which is a set of service identifiers of two terminal devices, an address of the second network of the relay device, and a second network of the relay device. A second management table storing one or a plurality of second entries including a third socket which is a set of service identifiers of the network; and a second terminal connected to the second network. When a packet addressed to a certain service is received, the values of the second socket and the third socket from the second management table are respectively set as a set of a source address and a source service identifier of the packet, and a destination. A second search for a second entry that is the same as the pair of the address and the destination service identifier
And if the second entry is not detected by the search by the second search unit, the same service identifier as the destination service identifier included in the packet from the first management table for the packet. First search means for searching for a first entry possessed; a set of the address of the first terminal device of the first entry detected by the first search means and a service identifier of the first entry Is a first socket, a set of a source address and a source service identifier of the packet is a second socket, and a set of a destination address and a destination service identifier of the packet is a third socket. First registration means for registering a second entry including the first socket, the second socket, and the third socket in the second management table; A communication program for causing the relay device to function as conversion means for rewriting the destination address of the packet to the address of the first terminal device of the first entry detected by the first search means. recoding media. 29. A means for rewriting the destination address of the packet to the address of the first socket of the detected second entry when the second entry is detected by the search by the second search means. 29. The recording medium according to claim 28, wherein the recording medium causes the relay device to function. 30. A recording medium recording a communication program of a relay device for connecting a first network and a second network having a different address system and a different service identifier from the first network, wherein: A first management table storing one or more first entries including an address of a first terminal device connected to a network and a service identifier of a service provided by the first terminal device; A first socket, which is a set of an address of a first terminal device connected to a first network and a service identifier of the first terminal device, and a second terminal device connected to the second network A second socket, which is a set of the address of the second terminal device and the service identifier of the second terminal device, and the address of the second network of the relay device and the Including a third socket is a set of a service identifier of the second network device one or a plurality of second
A second management table that stores an entry of one or more third entries including a service identifier used in the first network and a service identifier used in the second network for the same service. When a packet addressed to a certain service is received from a second terminal device connected to the second network, a third socket and a third socket are stored from the second management table. Second search means for searching for a second entry whose socket value is the same as the set of the source address and the source service identifier of the packet and the set of the destination address and the destination service identifier of the packet; When the second entry is detected by the search means, the service used in the second network is read from the third management table. Third search means for searching for a third entry whose discriminator value is the same as the source service identifier of the packet; third entry detected by the third search means for the source service identifier of the packet Means for rewriting to the service identifier of the first network, and rewriting the destination address and destination service identifier of the packet to the address and service identifier of the first socket of the detected second entry; and the second search means When the second entry is not detected, a fourth entry is searched from the third management table for a third entry having the same service identifier value as the destination service identifier of the packet used in the second network. Search means; service of the first network of the third entry detected by the fourth search means A first search unit for searching the first management table by using an identifier, an address of the first terminal device of the first entry detected by the first search unit, and a service identifier of the entry A first socket, a set of a source address and a source service identifier of the packet as a second socket, a set of a destination address and a destination service identifier of the packet as a third socket, A second entry including the first socket, the second socket, and the third socket is registered in the second management table, and further, a service identifier unused in the first network is registered. Selecting the selected service identifier into the first
Registering means for creating the third entry with the service identifier of the packet as the service identifier of the network and the service identifier of the packet as the service identifier of the second network, and registering the third entry in the third management table; The relay device has a function of rewriting a destination address and a destination service identifier to an address and a service identifier of the first terminal device of the detected first entry, and a unit for rewriting a source service identifier to the selected service identifier. A recording medium on which a communication program is recorded. 31. A recording medium recording a communication program of a relay device for connecting a first network and a second network having an address system and a service identifier different from the first network, the first network comprising: A first management table storing one or more first entries including an address of a first terminal device connected to a network and a service identifier of a service provided by the first terminal device; A first socket, which is a set of an address of a first terminal device connected to a first network and a service identifier of the first terminal device, and a second terminal device connected to the second network A second socket, which is a set of the address of the second terminal device and the service identifier of the second terminal device, and the address of the second network of the relay device and the Including a third socket is a set of a service identifier of the second network device one or a plurality of second
A second management table that stores an entry of one or more third entries including a service identifier used in the first network and a service identifier used in the second network for the same service. A third management table to be stored; and a packet addressed to a certain service received from a first terminal device connected to the first network, wherein a service identifier of the first network in the third management table is stored. Third search means for searching for the third entry whose value is the destination service identifier of the packet; and if the third entry is detected by the third search means, from the second management table The value of the first socket and the value of the second socket are respectively a set of the source address and the source service identifier of the packet, and the value of the packet. Second third entry destination address of Tsu bets to have been the search
Second search means for searching for the same second entry as the set of the service identifier of the network, and when the second entry is detected by the second search means, the destination service identifier of the packet is set to the Rewrite with the service identifier of the detected second socket,
Means for rewriting the source address and the service identifier of the packet to the address and service identifier of the third socket; and the source address of the packet if the second entry is not detected by the second search means. And a source service identifier as a first socket, and a set of a destination address of the packet and a service identifier of a second network of a third entry detected by searching the third management table as a first socket. And a service identifier unused in the second network is selected, and a set of the address of the second network of the relay device and the service identifier of the selected second network is set as a third socket. A second entry including the first socket, the second socket, and the third socket, Registering the selected service identifier in the second management table as the service identifier of the second network, and setting the source service identifier of the packet to the first service identifier;
Registering means for creating the third entry as a service identifier of the network of the above, and registering the third entry in the third management table; a destination service identifier of the packet as a service identifier of the second socket; A recording medium in which a communication program is recorded, wherein the relay device functions as means for rewriting a source service identifier to an address of the third socket and a service identifier. 32. When a registration request including an address and a service identifier of the first terminal device from a first terminal device connected to the first network is received, the registration request is included in the first management table. Means for storing a first entry including an address of the first terminal device included therein and a service identifier; and receiving a deletion request including the address of the first terminal device from the first terminal device; Searching the first management table for a first entry having the address of the first terminal device included in the deletion request, and causing the relay device to function as a unit for deleting the detected first entry. A recording medium on which the communication program according to claim 27, 28, 29 or 30 is recorded. 33. An operation confirmation request message is transmitted to a first terminal device connected to the first network, and the first terminal device receives the operation confirmation response message from the first terminal device, thereby receiving the first operation confirmation message. If the operation of the first terminal device is not confirmed, and the operation of the first terminal device cannot be confirmed, the first terminal device having the address of the first terminal device that transmitted the operation confirmation request message from the first management table.
33. The communication program according to claim 27, 28, 29, 30, or 32, wherein the relay device is caused to function as an operation confirmation request unit that searches for the first entry and deletes the detected first entry. Recording medium. 34. The system according to claim 27, wherein a first entry of said first management table includes processing capability information of a first terminal device connected to said first network. , 29, 30, 32 or 33. 35. When a capability notification message including an address of the terminal device and processing capability information is received from a first terminal device connected to the first network, the first terminal device receives the first notification from the first management table. A means for storing processing capability information included in the capability notification message in a first entry of one terminal device, wherein the relay device functions.
A recording medium recording the communication program according to 4. 36. When a plurality of first entries having the same service identifier as the destination service identifier included in the packet are detected, means for determining the first entry based on the processing capability information is provided to the relay device. A recording medium on which the communication program according to claim 34 or 35 is made to function. 37. A communication system comprising: a first network connected to a second network having an address system different from that of the first network via a relay device; and communication of a terminal device connected to the first network. A recording medium on which a program is recorded, wherein one or a plurality of first and / or second terminals including an address of a first terminal device connected to the first network and a service identifier of a service provided by the first terminal device A means for notifying a relay device having a first management table storing one entry of a registration request including an address of the terminal device and a service identifier of a service provided by the terminal device causes the terminal device to function. A recording medium on which a communication program is recorded. 38. The terminal device according to claim 37, wherein the terminal device has a function of notifying the relay device of a deletion request including the address of the terminal device.
A recording medium recording the communication program according to 1. 39. The communication program according to claim 37, wherein when the operation confirmation request message is received from the relay device, the terminal device functions as a means for transmitting an operation confirmation response message. recoding media. 40. A recording medium in which a communication program according to claim 37, 38 or 39, wherein said terminal device is made to function as means for notifying said relay device of processing capability information of said terminal device. 41. A first network and a second network having an address system different from that of the first network are connected via a relay device, and communication of a terminal device connected to the first network is performed. A recording medium on which a program is recorded, wherein one or a plurality of first terminals including an address of the own terminal device connected to the first network and a service identifier of a service provided by the own terminal device are provided. An entry is stored in a first management table of the relay device, and the relay device performs the first management on a packet addressed to a service from another terminal device connected to the second network. A first entry having the same service identifier as the destination service identifier included in the packet is searched from the table, and the destination address of the packet is searched. But the recording medium recording a communication program for executing receiving a first of said packet transmitted is rewritten to the address of the own terminal device of the entry detected by the search to the terminal device.