JPH0662084A - Data terminal equipment - Google Patents

Abstract

PURPOSE:To obtain data terminal equipment which provides communication with a host protocol via a network service access point address without changing the software of an X.25 protocol packet layer as equipment based on CCITT recommendation X.25 in 1980, etc. CONSTITUTION:When an HS user 3 is set in a working state, the execution address U1 of the NS user, A DTE address DTE 1 to be called, and an identification IDI are registered on a mapping table for a control means 4. When an incoming call packet is received, the DTE address to be called of the incoming call packet and an identifier in the field of call user data are fetched. The mapping table is searched setting fetched DTE address to be called and identifier as keys, and when coincidence is obtained in the addresses or identifiers, a received packet is notified to the NS user with coincidental address or identifier.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to X. The present invention relates to a data terminal device for performing communication between upper protocols such as OSI through software of 25 protocol packet layer.

[0002]

2. Description of the Related Art At present, packet switches and packet terminals have become widespread, and 1976 or 1980 version of CCITT.
Recommendation X. Many communication devices complying with the 25 protocol are used. In recent years, OSI has been defined in order to standardize the interface of the system, and the OSI of the communication system
Is expected. To do so, the existing X. X.25-compliant communication device upper-level software supports OSI. It suffices if the 25 protocols can be mapped to the upper software.

As a mapping method of this kind, 198
CCITT Recommendation X.4 and 1988. 25 Annex G (CCITT compliant DTE facility for providing OSI network services). This method uses a calling address extension and a called address extension facility to add a network service access point (hereinafter, N) in its field.
By storing an address (abbreviated as SAP) and notifying each other, NS (Network Service)
User entity and data terminal (hereinafter, DTE (Da
(Ta Terminal Equipment) abbreviated) address mapping method. According to this method, in the case of a packet switch and a packet terminal conforming to the previous standard recommended by CCITT in 1984,
Since there is no function for handling NSAP addresses, X. There is a problem that it cannot be used as a device that realizes 25.

Another method is ISO8878.
ANNEX A / X. 25 (1980) Subnetw
ork Dependent Convergence
Protocol: SNDCP has an existing X. 25
(1980) compliant DTE, 1984 edition X. Corresponds to 25 packet level protocol
A method for providing an SI connection-oriented network service is specified. Using this method, existing 1
980 version X. O using the packet network corresponding to 25
Although SI can be realized, it is necessary to mount the above-mentioned SNDCP on the data terminal device.

Further, as another conventional technique for solving the above-mentioned problem, there is a method described in Japanese Patent Publication No. 3-165143, for example. FIG. 13 is an explanatory diagram of a conventional mapping method. In this method, NSAP software that supports the OSI protocol corresponding to the NSAP address or software called NSAP user is prepared, and is called a user registration table in which the software and the DTE address are associated with each other as shown in FIG. Create a table for mapping. When the incoming call packet is received, the processing according to the flowchart shown in FIG. 13B is performed. That is, first, S3
At 1, the called DTE address is extracted from the incoming packet. Then, in S32, the called DT extracted
The user registration table is searched using the E address as a key. In S33, a match with the called DTE address is detected, and in S34, the software that matches the called DTE address is identified and the corresponding software (NS
(AP user) is notified of the incoming call reception. By performing these processes, X. Communication is realized by using devices that comply with the 25 recommendations.

However, in the above method, in order to uniquely determine the data terminal address and the NSAP software (NSAP user), when a plurality of NSAP users are supported, it is necessary to prepare the data terminal address for each NSAP user. There is. With this configuration, X. Two
There is a problem that the function of logical multiplexing of 5 protocols cannot be utilized.

[0007]

The present invention is based on the CCITT Recommendation X. X.25 of the packet switching station and the data terminal of the communication partner. X.25 protocol packet layer software without modification. 25
It is an object of the present invention to provide a data terminal device capable of realizing communication between higher level protocols such as OSI through the NSAP address of the protocol.

[0008]

The invention according to claim 1 is the same as that of the X. In data terminal equipment using the H.25 protocol, X.25. The registration function for registering the execution address, DTE address, and identifier of the higher-level software accessed through NSAP for the 25-packet level software and the X. 25. A control means having a comparison function for comparing the incoming DTE address and identifier in the incoming call packet with the registered data, and a connection function for selecting and connecting the upper software based on the comparison result. To do.

According to the second aspect of the invention,
X. In data terminal equipment using the H.25 protocol, X.25. NSA to 25 packet level software
A registration function for registering the execution address of the upper software accessed through P.P., the DTE address, and the DTE address of the other party who permits the incoming call in association with each other; Two
5 Control means having a comparison function for comparing the called and called DTE addresses in the incoming call packet with the registered data and a connection function for selecting and connecting the upper software based on the comparison result It is what

[0010]

According to the present invention, X. 25 packet level software execution address of higher-level software accessed through NSAP, DTE address and identifier, or DTE address and partner DTE that permits incoming call
Addresses are registered in association with each other, and the incoming DTE address and identifier in the incoming packet or the called and incoming D
By selecting the upper software in comparison with the TE address, a plurality of upper software can be associated with one DTE address. It is possible to perform network communication by making use of the logical multiplexing function of 25 protocols.

Further, when the DTE address and the DTE address of the other party to which the incoming call is permitted are registered in association with each other, the other party can be specified and communication can be performed, so that a security function can be provided.

[0012]

1 is a block diagram of a data terminal device according to an embodiment of the present invention and a data line terminating device (hereinafter referred to as DCE (Data).
a Circuit-Terminating Equ
FIG. 3 is a connection conceptual diagram of the data terminal device of the present invention. In the figure, 1 is DTE, 2 is DCE, 3
Is an NS user, 4 is a control means, 5 is an X. 25 packet layer processing unit.

The DTE 1 is connected to a communication line and is connected to a packet switching station, a DTE of a communication partner, and the like. FIG. 1 shows an example in which the DCE 2 is connected. DTE
1. There are a plurality of NS users 3 in the control unit 4 and the X. Packets can be sent and received via the 25-packet layer processing unit 5. NS user 3 is the OS
It is higher-level software that supports standards such as I. The control means 4 controls each N user from the plurality of NS users 3.
Information for identifying the S user, for example, the execution address of the NS user and the DTE address and identifier or D
The TE address and the DTE address of the other party to which the incoming call is permitted are associated and registered in advance. When there is an incoming call to DTE1, the incoming DTE address and identifier in the incoming packet or the called and incoming DTE addresses are compared with the registered data, and the NS user is selected. .
With such a function, a plurality of NS users 3 can be associated with one DTE address. X. Two
5 packet layer processing unit 5 uses X.5. Only the processing conforming to the 25 protocol is performed, and it is not necessary to modify it so as to perform processing related to higher level software. In FIG. 1, DTE1 and DC are connected by the communication lines corresponding to the number n of NS users.
Although it is connected to E2, n communication lines may be logically realized by only one or a plurality of communication lines. Also,
X. 25 Called DT to be called to the packet layer processing unit 5
The E address is not limited to one, but may be plural,
By using with the identifier and the calling DTE address, it is only necessary to use a DTE address that is less than the number of NS users.

FIG. 2 shows the X. It is a schematic diagram of a format of 25 packets. In the figure, the part surrounded by the alternate long and short dash line indicates that the data has variable length, and the part surrounded by the broken line indicates that the data can be omitted. If the DTE address and identifier are used to identify the NS user, the identifier can be written in the field of the call user data. The DTE address may refer to the called DTE address field. When using the called and calling DTE addresses,
The called DTE address field and the calling DTE address field in the packet may be referred to, respectively.

FIG. 3 is an explanatory diagram of an example of the mapping table. FIG. 3A shows an example of the mapping table when the DTE address and the identifier are used.
(B) shows an example of a mapping table when the called and calling DTE addresses are used. An X. format of the format as shown in FIG. If there are 25 incoming call packets, the called DTE address and the identifier in the field of the call user data from the incoming call packet or the called DT
Referring to the E address and the calling DTE address, FIG.
(A) or the called DTE address and identifier registered in the mapping table shown in FIG.
Get the execution address of the user. Based on the obtained execution address, it connects to the NS user. In this way, by using the mapping table, it is possible to map a plurality of NS users to one DTE address. Further, as shown in FIG. 3 (B), when the calling DTE address is registered in the mapping table, the other party with whom the communication is performed is specified, which is also effective in terms of security. The execution address of the NS user may store the actual address to be executed, but may be any data that can identify the NS user, such as a uniquely determined name.

FIG. 4 is a schematic configuration diagram of a first concrete example of the data terminal device of the present invention, and FIG. 5 is an explanatory diagram of an example of a mapping table used in the first concrete example. In the figure, the same parts as those in FIG. In this example, the called DTE address and identifier are used to
A case of identifying a user will be described. DTE1 is
For example, assume that it has two DTE addresses and three NS users. Then, two NS users are registered for the DTE address DTE1 and one NS user is registered for the DTE address DTE2. Three
The two NS users 3 are higher level software that communicates through the NSAP address. NS user has execution address U1, DTE address DTE1, identifier ID
Identified by 1. Similarly, the NS user has the execution address U2 and is identified by the DTE address DTE1 and the identifier ID2, and the NS user has the execution address U3 and the DTE address DTE2 and the identifier ID3.
Specified by.

The operation of the first specific example will be described. N
When the S user becomes available, the execution address U1, the DTE address DTE1, and the identifier ID1 of the NS user are registered in the mapping table with respect to the control means 4, as shown in FIG. When the NS user is unavailable, "0" is set in the execution address U1 of the NS user.
Has been inserted.

FIG. 6 is a flow chart showing an example of processing of an incoming call packet in the first specific example. When the incoming call packet is received, in S11, the called DTE address is extracted from the address field of the incoming call packet.
Further, in S12, the identifier is extracted from the field of the call user data of the incoming call packet. In S13, the mapping table is searched using the retrieved called DTE address and identifier as a key. In S14, it is determined whether or not a match is found as a result of the search, and if found, in S15, the received packet is notified to the NS user corresponding to the called DTE address and identifier. In this way, in the received incoming call packet, the NS user is specified by the called DTE address and the identifier, and communication can be performed. If a match with the called DTE address and identifier is not found in S14, a disconnection request packet is sent out in S16, and the process ends.

FIG. 7 is a schematic configuration diagram of a second specific example of the data terminal device of the present invention, and FIG. 8 is an explanatory diagram of an example of a mapping table used in the second specific example. In the figure, the same parts as those in FIG. Also in this specific example, the called DTE address and the identifier are used for NS.
It identifies the user. In this specific example, X.X. This is a specific example in which software configured to manage 25 circuits and having means for managing a circuit with DTE address 1 and means for managing a circuit with DTE address 2 is used. Similar to FIG. 4, DTE1 has three NS users, and has two NS users for DTE address 1.
Register one NS user for TE address 2.
The mapping table to be registered may have the format shown in FIG. 5 used in the first specific example, but since it is managed separately for each DTE address, as shown in FIG. It is also possible to create a mapping table with identifiers. Further, in order to refer to each mapping table, the DTE address and the pointer pointing to the mapping table may be created as one reference table. In the second specific example shown in FIG. 7, in the mapping table of DTE address 1,
The execution address U1 of the NS user and the identifier ID1 and the execution address U2 of the NS user and the identifier ID2 are registered, and N is registered in the mapping table of the DTE address 2.
The execution address U3 of the S user and the identifier ID3 are registered.

The operation of the second specific example will be described. N
When the S user becomes available, the execution address U1 and the identifier ID1 of the NS user are registered in the mapping table of the DTE address 1 with respect to the control means 4. When the NS user is disabled, "0" is inserted in the execution address U1 of the NS user.

When the incoming packet is received, it is accepted for each called DTE address of the incoming packet. And
From the call user data field of the incoming packet,
Retrieve the identifier. The mapping table is searched using the extracted identifier as a key, and if a matching one is found, the NS user is notified of the received packet. In this way, in the incoming packet accepted for each called DTE address, the NS user is specified by the identifier,
Can communicate. If a match with the identifier is not found, a disconnection request packet is sent and the process ends. The above processing is similarly performed for DTE address 2.

FIG. 9 is a schematic configuration diagram of a third concrete example of the data terminal device of the present invention, and FIG. 10 is an explanatory diagram of an example of a mapping table used in the third concrete example. The reference numerals in the figure are the same as those in FIG. 4, and a description thereof will be omitted. In this specific example, a case will be described in which the NS user is specified using the called and calling DTE addresses. DTE1 has, for example, two DTE addresses and has three NS users.
Have one. And the DTE address DT
Two NS users are registered for E1 and one NS user is registered for DTE address DTE2. Also, the NS user is connected to the partner having the DTE address SA1, and the NS user is connected to the DTE address SA1.
2 and the NS user is connected to the partner with DTE address SA3. The NS user has the execution address U1 and is specified by the self (called) DTE address DTE1 and the partner (calling) DTE address SA1. Similarly, the NS user has the execution address U2 and is specified by the self (called) DTE address DTE1 and the partner (calling) address SA2, and the NS user has the execution address U3 and is the self (called) It is specified by the DTE address DTE2 and the partner (calling) address SA3.

The operation of the third specific example will be described. N
When the S user becomes available, the execution address U1, the own DTE address DTE1, and the partner DTE address SA1 of the NS user are sent to the control means 4 as shown in FIG.
Register in the mapping table as shown in. When the NS user is disabled, "0" is inserted in the execution address U1 of the NS user.

FIG. 11 is a flow chart showing an example of processing of an incoming call packet in the third specific example. When the incoming call packet is received, the called DTE address is extracted from the address field of the incoming call packet in S21. Similarly, in S22, the calling DTE address is extracted from the address field of the incoming packet. S2
In 3, the mapping table is searched by using the retrieved called and calling DTE addresses as keys. S2
In 4, it is determined whether or not a match is found as a result of the search, and if found, in S25, the received packet is notified to the NS users corresponding to the called and calling DTE addresses. In this way, in the received incoming call packet, the NS user is specified by the called and calling DTE addresses, and communication can be performed. If a match with the called and calling DTE addresses is not found in S24, a disconnection request packet is sent out in S26 and the process ends.

FIG. 12 is an explanatory diagram showing an example of a mapping table when one DTE address is included in the DTE. In the first to third specific examples described above, DTE1
Although the case of having a plurality of DTE addresses is described in the above, it is also possible to configure to have only one DTE address. In this case, since there is always only one DTE address, the data registered in the mapping table includes the execution address of the NS user and the identifier or calling D
Only the TE address is required. The mapping table in the case of using the identifier can be configured as shown in FIG. When using the calling DTE address,
It can be configured as shown in FIG. In this way, when there is one DTE address in the DTE, as shown in FIG.
It will be simpler compared to Fig.

[0026]

As is apparent from the above description, according to the present invention, by mapping the NS user and the called DTE address and the identifier or the calling DTE address, one data terminal address is mapped. It is possible to map a plurality of NS users, and there are many popular ones, such as CCITT 1980 X.264. Equipment that complies with the Recommendations No. 25 protocol Packet layer OS without changing the software through NSAP address
Communication between higher level protocols such as I can be realized. Further, when mapping is performed using the called user and the calling DTE address with the NS user, the communication partner can be specified, which is also useful from the security aspect.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a configuration of an embodiment of a data terminal device of the present invention and a connection between a data line terminal device and a data terminal device of the present invention.

FIG. 2 X. It is a schematic diagram of a format of 25 packets.

FIG. 3 is an explanatory diagram of an example of a mapping table.

FIG. 4 is a schematic configuration diagram of a first specific example of a data terminal device of the present invention.

FIG. 5 is an explanatory diagram of an example of a mapping table used in the first specific example.

FIG. 6 is a flowchart showing an example of processing of an incoming call packet in the first specific example.

FIG. 7 is a schematic configuration diagram of a second specific example of the data terminal device of the present invention.

FIG. 8 is an explanatory diagram of an example of a mapping table used in the second specific example.

FIG. 9 is a schematic configuration diagram of a third example of the data terminal device of the present invention.

FIG. 10 is an explanatory diagram of an example of a mapping table used in a third specific example.

FIG. 11 is a flowchart showing an example of processing of an incoming call packet in the third specific example.

FIG. 12 is an explanatory diagram showing an example of a mapping table when one DTE address is included in a DTE.

FIG. 13 is an explanatory diagram of a conventional mapping method.

[Explanation of symbols]

1 DTE, 2 DCE, 3 NS user, 4 control means, 5 X. 25 packet layer processing unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location 8020-5K H04L 13/00 307 A 8020-5K 309 A

Claims (2)

[Claims] 1. X. In data terminal equipment using the H.25 protocol, X.25. A registration function for registering the execution address, the data terminal address, and the identifier of the higher-level software accessed through the network service access point for the 25-packet level software,
X. 25 control means having a comparison function for comparing the incoming data terminal address and identifier in the incoming call packet with the registered data, and a connection function for selecting and connecting the upper software based on the comparison result Data terminal equipment. 2. X. In data terminal equipment using the H.25 protocol, X.25. The registration function of registering the execution address of the higher-level software, the data terminal address, and the data terminal address of the other party who permits the incoming call in association with the 25 packet level software through the network service access point; 25. A control means having a comparison function for comparing the called and called data terminal addresses in the incoming call packet with the registered data and a connection function for selecting and connecting the upper software based on the comparison result. Characteristic data terminal device.