JPH03123241A - Data communication system - Google Patents

Abstract

PURPOSE:To attain the communication with plural opposite terminal equipments in a non-packet form terminal equipment by referencing a conversion table at reply of a polling of the non-packet form terminal equipment and extracting an information relating to the logical connection of PVC to control the communication with the opposite terminal equipment. CONSTITUTION:A packet multiplexer 6 sends a command added with a polling address for packet form terminal equipments 4a, 4b of a communication opposite party to a non-packet form terminal equipment 1 to apply a polling. The multiplexer 8 receiving the reply discriminates a polling address of the information replied by a terminal equipment communication control section 7 or the like and references a conversion table 10 based thereon. The control section 7 extracts the information relating to the logic connection 5a of the PVC to the terminal equipment 4a requested by the terminal equipment 1 for the communication and given the information to a protocol conversion section 8. The conversion section 8 generates a reset transmission request further and informs it to a network communication control section 9. The control section 9 sends a packet RQ requesting a reset to a packet exchange network 3 and the packet RQ is sent to the terminal equipment 4a by the logic connection 5a of the PVC.

Description

[Detailed description of the invention] [Industrial application field]

This invention enables a non-packet type terminal housed in a packet multiplexer to communicate with a partner terminal connected to a packet switching network using a permanent virtual circuit (hereinafter referred to as PVC).
It relates to a data communication system that communicates via logical connections of

[Conventional technology]

FIG. 4 shows, for example, Mitsubishi Electric Technical Report Vol. 1.61. Nα1
2 (December 1987), pages 18 to 22, is a system configuration diagram showing a conventional data communication system. In the figure, la and lb are non-packet type terminals not equipped with a packet assembly/disassembly function, and 2 is a packet multiplexing device that accommodates these non-packet type terminals 1a and lb. 3 is a packet switching network to which this packet multiplexing device 2 is connected, 4a and 4b are each equipped with a packet assembly and disassembly function and are accommodated in this packet switching network 3, and the non-packet type terminals 1a and lb This is a packet-type terminal that serves as a partner terminal to communicate with. Further, 5a and 5b connect the packet multiplexer 2 and the packet type terminals 5a and 5b in order to connect between the non-packet type terminal 1a and the packet type terminal 4a or between the non-packet type terminal 1b and the packet type terminal 4b. This is a logical connection of PVC set between. Logical connection 5 of this PVC
As shown by broken lines, a and 5b are connected to predetermined non-packet type terminals 1a and lb via physical lines between the packet multiplexer 2 and the non-packet type terminals 1a and lb. Next, the operation will be explained. Here, FIG. 5 is a time chart showing the operation sequence. This time chart shows SNA/5DLC← which converts the protocol based on 18M's System Network Architecture (SNA) and Synchronous Data Link Control Procedure (SDLC) to the protocol based on the X, 25 procedure recommended by SNA and CCITT. →SNA
The operating sequence for /X,25 conversion is shown. Packet type terminal 4 accommodated in packet switching network 3
When communicating with a as the communication partner, a non-packet type terminal 1a connected to the packet type terminal 4a by a PVC logical connection 5a responds to polling sent from the packet multiplexer 2. That is,
According to the example shown in FIG. 5, in response to the command SNRM sent from the packet multiplexer 2, a response UA is returned from the non-packet type terminal 1a. When the packet multiplexing bag W2 detects this response UA returned from the non-packet type terminal 1a, it transmits a packet RQ requesting reset to the PVC logical connection 5a, and starts communication with the packet type terminal 4a. . Hereinafter, between the packet multiplexer 2 and the packet type terminal 4a, the logical connection 5a of the PVC is connected as shown in FIG.
Via Reset II! packets requesting link establishment Q SM. The acknowledgment packet QU, etc. are exchanged, and a frame RR indicating that information can be received is exchanged between the packet multiplexer 2 and the non-packet type terminal 1a. Thereafter, communication data is transmitted and received between the packet multiplexer 2 and the packet-type terminal 4a using data packets DT, and between the packet multiplexer 2 and the non-packet-type terminal 1a using information frames I. In addition, when communicating with another packet type terminal 4b, the command S sent from the packet multiplexer 2
In response to polling by NRM, the non-packet type terminal 1b connected to the packet type terminal 4b through the PVC of the logical connection 5b responds with a response UA in the same manner as in the above case. Thereafter, the processing proceeds in the same sequence as in the above case, and via the PVC logical connection 5b,
Communication is performed between the non-packet type terminal 1b and the packet type terminal 4b.

[Problem to be solved by the invention]

Since the conventional data communication system is configured as described above, the packet multiplexer 2 and the packet format terminal 4a
, 4b are connected by a PVC logical connection 5a, 5b, the other terminal with which the non-packet type terminals 1a, Ib can communicate is the packet type terminal 4a connected by this PvC logical connection 5a, 5b. Alternatively, the terminal 4b is uniquely determined, and the communication partner cannot be freely selected, and the non-packet type terminal 1a, I
There was an issue in that it was necessary to prepare b. This invention was made in order to solve the above-mentioned problems.
An object of the present invention is to obtain a data communication system that makes it possible to communicate with a plurality of partner terminals connected by C logical connections.

[Means to solve the problem]

The data communication system according to the present invention sets up a PVC logical connection between a non-packet type terminal and all partner terminals with which the non-packet type terminal communicates, and causes a packet multiplexer to identify the partner terminals. A conversion table that describes the correspondence between the identification information of the terminal and the logical connection of PvC to the other terminal, and this conversion table is referred to when a non-packet type terminal responds to polling, and information regarding the logical connection of the corresponding PVC is extracted. This system includes a terminal-side communication control section and a network-side communication control section that controls communication with the other terminal based on the extracted information regarding the logical connection of the PVC.

[Effect]

The packet multiplexing device in this invention refers to the conversion table at the time of polling response from a non-packet type terminal, and
Using identification information such as a polling address to identify the terminal to communicate with, PVC to the corresponding terminal during the logical connection of PVC set up between all the terminals with which the non-packet type terminal communicates. A single non-packet terminal can communicate with multiple terminals based on specifications from the non-packet terminal by extracting information regarding the logical connection of the terminal and controlling communication with the terminal based on that information. Realize a data communication system that allows

【Example】

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 3 is a packet switching network and 4a. 4b is a packet type terminal, and 5a and 5b are PVC logical connections, which are the same or equivalent parts to those of the conventional device denoted by the same reference numerals in FIG. 4, and detailed explanation thereof will be omitted. 1 is Ia in FIG. This is a non-packet type terminal that does not have the function of assembling and disassembling packets, which is equivalent to the non-packet type terminal shown in 1b. Reference numeral 6 denotes a packet multiplexing device to which the non-packet type terminal 1 is connected via a physical line. This is different from the conventional packet multiplexing device 2 shown in FIG. FIG. 2 is a block diagram showing the configuration of this packet multiplexing device 6. In FIG. A communication control unit 8 is a protocol conversion unit that converts the protocol between the non-packet type terminal 1 and the packet multiplexing device 6 and the protocol between the packet multiplexing device 6 and the packet switching network 3. Reference numeral 9 denotes a packet-type terminal 4a connected via the packet switching network 3. 10 is a network side communication control unit that controls communication with the packet type terminals 4a and 4b, and 10 is a network side communication control unit that controls communication with the packet type terminals 4a and 4b, and identification information such as a polling address for identifying the packet type terminals 4a and 4b, and the packet type terminals 4a and 4b.
Logical connection 5a of PVC to b. This is a conversion table that describes the correspondence with 5b. Next, the operation will be explained. Here, Figure 3 shows SNA
/S D L C (-+ S NA / Command #I SNRM, #2S with polling address added for each
Polling is performed by sending NRM. When communicating with the packet type terminal 4a, it responds to polling sent from the packet multiplexer 6 using the command #ISNRM with a response #IUA. When the packet multiplexing device 6 receives this response, the terminal-side communication control unit 7 determines the polling address, etc. of the responded information, and refers to the conversion table 10 based on the polling address. By referring to this conversion table 10, the terminal-side communication control unit 7 extracts information regarding the PVC logical connection 5a to the packet-type terminal 4a with which the non-packet type terminal 1 has requested communication, and sends it to the protocol conversion unit 8. hand over. The protocol conversion unit 8 further generates a reset transmission request from the received information and notifies the network side communication control unit 9 of the reset transmission request. The network side communication control unit 9 that received the notification exchanges the bucket '4143.
A packet RQ requesting a reset is sent to the host. This packet 1-RQ is sent to the packet form terminal 4a via the PVC logical connection 5a, and communication is started. Thereafter, as shown in FIG. 3, between the packet multiplexer 6 and the packet type terminal 4a, a reset confirmation packet RF, a link establishment request packet QSM, and its acknowledgment packet QUA are sent via the logical connection 5a of the PVC. etc., but
Additionally, a frame #IRR indicating that information can be accepted between the packet multiplexer 6 and the non-packet type terminal
is mutually given and received. Thereafter, communication data is transmitted and received between the packet multiplexer 6 and the packet-type terminal 4a using the data bucket (DT), and between the packet multiplexer 6 and the non-packet-type terminal 1 using the information frame #II. In addition, when communicating with another packet type terminal 4b, the command #
In response to polling by 2SNRM, non-packet type terminal 1 responds with response #2UA. Thereafter, the processing proceeds in the same sequence as in the above case, and the communication between the same non-packet type terminal l and the packet type terminal 4b is
This is done via a PVC logical connection 5b. In the above embodiment, the packet-type terminals 4a and 4b equipped with the function of assembling and disassembling packets are used as the counterpart terminals of the non-packet-type terminal, but the packet-switching network 3 accommodating them is If the terminal has a packet assembly/disassembly function, a non-packet type terminal without the packet assembly/disassembly function may be used as the destination terminal, or a packet multiplexer equipped with a packet assembly/disassembly function may be used as the destination terminal. It is also possible to use non-packet type terminals by accommodating them in the packet switching network 3, and in either case, the same effects as in the above embodiment can be achieved. Effects of the Invention As described above, according to the present invention, a PVC logical connection is established between a non-packet type terminal accommodated in a packet multiplexing device and all partner terminals with which the non-packet type terminal communicates. is set, and the packet multiplexing device is provided with a conversion table that describes the correspondence between the identification information that identifies the other terminal and the logical connection of PVC to the other terminal, and this conversion table is used when a non-packet type terminal responds to polling. In reference to,
Since the configuration is configured to extract information regarding the logical connection of the corresponding PVC and control communication with the other terminal based on that information, 1.
A single non-packet terminal can communicate with multiple partner terminals,
This has the effect of providing a data communication system that does not require preparing a non-packet type terminal for each partner terminal with which one wishes to communicate.

[Brief explanation of drawings]

Fig. 1 is a system configuration diagram showing a data communication system according to an embodiment of the present invention, Fig. 2 is a block diagram showing its packet multiplexing device, Fig. 3 is a time chart showing its operation sequence, and Fig. 4 is a system configuration diagram showing a data communication system according to an embodiment of the invention. A system configuration diagram showing a conventional data communication system, and FIG. 5 is a time chart showing its operation sequence. 1 is a non-packet type terminal, 3 is a packet switching network, 4a,
4b is the other party terminal (packet type terminal), 5a and 5b are P
6 is a packet multiplexing device, 7 is a terminal side communication control unit, 9 is a network side communication control unit, and 10 is a conversion table. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. 1- Non-j

Claims (1)

[Claims] A packet multiplexing device in which a non-packet type terminal is accommodated is connected to a packet switching network, and the non-packet type terminal is connected via the packet multiplexing device to a partner terminal connected to the packet switching network and a permanent virtual circuit. In the data communication system, the permanent virtual circuit logical connection is set between the non-packet type terminal and all the partner terminals with which the non-packet type terminal communicates, and the packet multiplexing device a conversion table that describes the correspondence between identification information for identifying the partner terminal and the logical connection of the permanent virtual circuit to the partner terminal; controlling communication and referring to the conversion table when the non-packet type terminal responds to polling;
a terminal-side communication control unit that extracts information regarding the logical connection of the corresponding permanent virtual circuit; A data communication system comprising: a network side communication control unit that controls communication with the connected terminal.