JPS62112439A - Network system - Google Patents

Abstract

PURPOSE:To form a flexible network system by using a part of a DTE number of a call packet for path and setting as an equipment number in a local area network for a medium access control. CONSTITUTION:The program executed by a control section 2 is stored in advance in a ROM 5 and executed when an X.25 communication control section 3 receives a packet. When a calling packet is received, it is required to set the call of new X.25. The number table management corresponding the equipment number in the LAN and the DTE number is disused by making the equipment number in the LAN set to a LAN communication control section 1 coincident with the DTE number of the X.25 communication control section 3. Further, the means of path selection of the packet to be sent to attained by referencing only the incoming DTE number in the X.25 call packet. Thus, the software load of the communication controller 10 is relieved and the network extension is easily attained at the same time.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is for connecting a plurality of packet-type terminals to, for example, a bus type or loop type (also referred to as ring type) local area network (hereinafter abbreviated as LAN). The present invention relates to a network system.

[Prior Art] Conventionally, in a private packet switching network using a LAN, network layer control according to the CCITT Recommendation network protocol management such as protocol control, and the DTE number given to the packet type terminal that performs packet exchange and the device number in the LAN to which that terminal is actually connected.
It is necessary to manage both.

Furthermore, when transmitting a packet to another communication control device via the LAN, it is necessary to know what device number the packet format terminal with the DTE number specified as the destination has within the LAN. It is necessary to create and manage a name table that associates DTE numbers with device numbers within the LAN.

The various management requirements described above are due to the need for layered protocols, such as the 7-layer O5I model, to ensure consistency when a network connects to other networks.

[Problems to be Solved by the Invention] Therefore, in the past, two numbers were required to actually identify one terminal, and the management thereof became complicated. There were various drawbacks, such as the need to modify the number tables of all communication control devices when there was a subscription.

The present invention has been made in view of the problems of the prior art described above, and its purpose is to provide a network system that combines a packet switching network and a local area network, which facilitates route selection and system management, and The aim is to propose a network system that is flexible for system expansion.

[Means for Solving the Problems] As a means for achieving the above-mentioned problems, for example, the network system of the embodiment shown in FIG.
A plurality of communication control devices 1o1, 102. ...
103 are connected to each other. Each communication control device 101
, 102...103 are packet type terminals 111, 112, . . . each having an image information output device such as a scanner, and a data processing device such as a printer or word processor.
・113 is connected. The packet-type terminals then exchange data using communication media via their respective communication control devices. In each communication control device, the device number for media access control is DT for packet switching control.
It will be part of the E number. For example, in the communication control device 101, the DTE number is 4-digit 0BOI'', and the device number is DT
The last two digits of the E number are "01".

[Operation] In the above configuration, since the device number for media access control is the same as a part of the I) TE number for packet switching control, for example, the called DTE number in the calling packet is used when setting a route. A part of it can be used as the destination device number.

Therefore, it is possible to flexibly respond to the addition of packet type terminals, etc., and at the same time, the degree of freedom in setting the DTE number is increased compared to the case where the DTE number and the LAN device number are all the same.

[Embodiments] Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

<Overview of Embodiment> FIG. 2 shows a network system according to an embodiment of the present invention, in which a plurality of packet-type terminals are connected to a local area network 100 via a communication control device 10. A packet type terminal can be defined as a general terminal having a packet disassembly and assembly (PAD) function. The network system shown in FIG. 2 forms a private packet switching network system.

FIG. 3 is a block diagram showing the main configuration of the communication control device 1o of this embodiment. In FIG. 3, 1 is a LAN communication control unit for media access control for connection to the LAN 100, and 2 is a control unit that controls the overall operation of the communication control device 10, which is composed of a microcomputer or the like. has been done.

3 is an X for connecting a packet type terminal, 25 is a communication control section, 4 is a random access memory (RAM) used by the control section 2, and 5 is an X, 2'5 protocol executed by the control section 2, for example. Control program, program for controlling L, AN.

A read-only memory (ROM) 6 stores programs for control procedures as shown in FIGS. 8, 9(a), and 10(a); This is a self-device number setting unit used for comparing whether the number is correct or not.

(Calling Packet) Figure 5 is a format diagram of the X,25 calling packet used in the X,25 communication control unit 3 of this embodiment.The format of the figure is based on the CCITT recommendation x,25. 11 is the general format identifier, 12 is the logical channel group number, 13 is the logical channel number, 14 is is the calling DTE number length, 16 is the called DTE number length,
The calling DTETE 118 is used as the called DTE number.

<Transmission/Reception Frame> FIGS. 6(a) and 6(b) are general format diagrams of a LAN frame used in the LAN communication control unit of this embodiment. In FIG. 6(a), 21 is a preamble for synchronizing frames, 22 is a frame destination device number, 23 is a frame source device number, and 24 is an L
Control information field for controlling AN frame, 2
Reference numeral 5 denotes a data section, and in a third embodiment to be described later, call packets are stored in this data section 25 at the time of route setting and are broadcasted all at once. 26 is a frame check sequence (Fe2) for detecting errors on the LAN, and 27 is a postamble indicating the end of the frame.

FIG. 6(b) shows the format of a frame for acknowledging the simultaneous broadcast communication in the third embodiment described above, and 31 is a preamble for frame synchronization;
32 is the destination device number of the acknowledgment frame, 33 is the source device number of the acknowledgment frame, 34 is control information indicating that it is an acknowledgment frame, and 35 is a frame check sequence for detecting errors on the LAN ( Fe2
), 36 is a postamble indicating the end of the frame.

(RAM Configuration) Figure 4 shows the configuration of data stored in RAM4.4
A frame storage area 1 stores frames exchanged on the LAN. A packet storage area 42 stores packets exchanged between the packet type terminal and the X, 25 communication control unit 33. 43 is the device number offset 43,
The amount of offset of the LAN device number (ie, the destination device number 22) in the called DTE number 17 is shown.

<Call Setting Sequence> FIG. 7 is a conceptual diagram illustrating a call setting (route selection) sequence in three actual 2i1 examples described below.

This will be explained according to FIG. First, the packet-type terminal of the calling DTE sends a calling packet (FIG. 5) to its own communication control device for call setup. The communication control device sends a frame (FIG. 6(a)) containing the calling packet onto the LAN medium 100 according to, for example, a bit-oriented protocol. The communication control device on the called side learns that it has been selected from the destination device number 22 in the frame, and
The communication flilJ control device 10 establishes a route by sending an incoming call packet to the incoming packet type terminal connected to itself. Once the route is set, data transfer is thereafter performed using the logical channel number 13 and the destination number 22 that has already been set.

If route connection confirmation is particularly required, the called side communication control device 10 sends a confirmation response frame (for example, FIG. 6(b)) onto the LAN 100.

The communication control device 10 on the calling side receives this confirmation response frame and completes the route selection. Furthermore, the called side packet-format terminal sends an incoming call acceptance packet to its own communication control device, and the called side communication control device 10 sends a transmission frame containing the incoming call acceptance packet onto the LAN 100. This connection confirmation is theoretically necessary only in the third embodiment described below, and is basically unnecessary in the first and second embodiments.

The present invention will be specifically explained using the following three examples.

<First embodiment> The embodiment shown here eliminates the need for number table management by making the device number set in the LAN communication control unit 1 and the DTE number set in the X, 25 communication control unit 3 the same. At the same time, since the called DTE number in the calling packet matches the LAN device number of the packet-forming terminal to be sent, route selection can be made simply by referring to the called DTE number.

The details of this embodiment will be explained with reference to the flowchart of FIG. This program executed by the control unit 2 is R
It is stored in OM5.

25 is executed when the communication control unit 3 receives a packet. First, in step S1, a packet is received from the X, 25 communication control unit 3. This received packet may be a calling packet for route establishment, or it may be a packet for normal data transfer after route establishment. It is checked by the packet type 104 whether the packet received in step S2 is an X,250 calling packet.

If a calling packet is received here, the new X, 25
call must be set up. Therefore, the process advances to step S3, and the called DTE number 17 in the calling packet is set to the destination device number 22. This is possible because the DTE number and LAN device number of each packet type terminal are the same. The flowchart proceeds to step S4. If it is determined in step S2 that the packet is not a calling packet, the process directly proceeds to step S4. If it is determined in step S2 that the packet is not a calling packet, the route has already been selected, so the data is transferred using the logical channel number 13 and the destination number 22 that has already been set. There's no need to do it.

In step S4, the entire packet received by the X,25 communication control section 3 is stored in the data section 25 of the LAN frame. This is to enable the called side to know that the frame is being sent for route setting. Then, in step S5, control information 2 necessary for controlling the LAN is
4, and in step S6, the own device number set in the device number setting section 6 is set to the source device number 23 in the LAN frame. In this way, a LAN frame for route setting is transmitted on the LAN communication medium 100. The communication control device on the called side checks the destination device number 22 in the LAN frame, learns that the route is to be set to itself, and captures the LAN frame. If necessary, an acknowledgment frame (FIG. 6(b)) is sent to the calling side communication control device. In this case, the LAN device number and DTE
Since the numbers are the same, there is basically no need to send an acknowledgment frame.

<Effects of the first embodiment> According to the embodiment described above, the LAN device number and X set in the LAN communication control unit 1, and the DT of the communication control unit 3
By making the E numbers the same as the
, 25 by referring only to the incoming call DTE number in the outgoing call packet, it is possible to reduce the software load on the communication control device 1o and at the same time, it is possible to easily expand the network.

<Second Embodiment> The embodiment described here is similar to the first embodiment described above in that it eliminates the need to manage a number table for LAN device numbers and DTE numbers, and aims for flexibility in expanding the network system. However, by making its own LAN device number and DTE number partially the same, the communication control device 10 of each packet-type terminal in the network system can identify one of the called DTE numbers in the calling packet when setting a route. By making it possible to select a route simply by referring to the LAN device number of the destination packet format terminal, this not only ensures flexibility for expansion of the network system described above, but also
The feature is that the E number can be set freely to some extent.

FIG. 9(a) is a flowchart of the operating procedure of this embodiment. FIG. 9(b) is a diagram illustrating the operational concept for obtaining the destination LAN device number from the called DTE number 17. The process will be explained according to the flowchart of FIG. 9(a) while referring to FIG. 9(b). Step S11. Step S
12 is step S1 in FIG. 8 of the first embodiment. Step S
Since it is the same as 2, the explanation will be omitted. A case will be described in which the packet received by the X, 25 communication control unit 3 in step S11 is a calling packet.

In step S13, the destination device number 22 is obtained from the called DTETE 11. That is, as shown in FIG. 9(b), the incoming DT
The contents of ETE11 are 4 digits 1234'', and the RAM
The contents of device number offset 43 stored in 4 are “
2'', that is, the destination device number is stored from the third digit of the incoming DTETE11. Then, in step 313 and step S14, the incoming DTTE
The last two digits “34” in E number 17 are destination device number 22.
be purified by

The control procedure from step 315 onward is the same as the control procedure from step 54 onward in FIG. 8 of the first embodiment, so a description thereof will be omitted.

<Effects of the second embodiment> According to the second embodiment described above, the DT of the X25 communication control unit, which is the LAN device number set in the LAN communication control unit 1,
By setting in advance in the communication control device 10 which part of the total DTE number is the device number within the LAN, the DTE number can be set as a part of the E number, and the LAN Internal device number and DTE
This has the effect of eliminating the need to manage a number table that corresponds to the numbers.

Furthermore, the means for selecting the route of the packet to be transmitted can be made based on the position of the device number within the LAN set in advance in the communication control device 10, thereby reducing the software load on the communication control device 10. At the same time, it is possible to easily expand the network.

<Third Embodiment> In the first and second embodiments, the incoming DTETE 11 and the destination device number 22 are at least partially the DTE number and LAN device number assigned to the packet type terminal itself. This was an example of the same. The third embodiment described here is characterized in that it is possible to set a route even if the two numbers given to the communication control device do not match, and at the same time it eliminates the need for number table management. For this purpose, a LAN mechanism called simultaneous broadcast communication is used.

FIG. 10(a) is a flowchart of the control procedure of this embodiment. FIG. 10(b),(C).

(d) is a diagram of an example of a network system, - a transmission frame for simultaneous broadcast communication, and an acknowledgment frame therefor; The flowchart of FIG. 10(a) will be explained based on the examples of FIGS. 10(b) to (d). Step S21. Step S22 is step Sl of the first embodiment,
Since it is the same as step S2, the explanation will be omitted. Therefore, a case will be described in which the packet received by the X.25 communication control unit 3 in step S21 is a calling packet.

In the example of FIG. 10(b), it is assumed that a route is set between the communication control device 101 and the communication control device 103. The DTE numbers of the communication control devices 101 and 103 are two-digit OA"
, “OC device, and the device number is 2 digits 01” and “0.”
3''. Then, in step S23, the image shown in FIG. 10 (
As in C), - Destination device number 2 of the broadcast communication frame
2 is a number indicating that it is a simultaneous broadcast communication, e.g. ``FF''
shall be. Next, in step S24, the self address "'Of" set in the device number setting section 6 is stored in the source device number 23 of the broadcast communication frame, and in step S25, the received packet (calling packet) is stored in the transmitting frame. In step 326, control information for LAN control is stored in the control information 24, and in step S27.
The simultaneous broadcast communication frame assembled in LAN communication medium 10
Send on 0.

Step 328 is a step of determining whether an acknowledgment is necessary. This judgment is made because when setting a new route, it is necessary to receive an acknowledgment frame to confirm the completion of route connection and to know the LAN device number of the destination. That is, only the communication control device 103 whose DTE number ("'oc") in the data section 25 of the broadcast transmission frame matches its own DTE number is shown in FIG. 10(d').
Returns an acknowledgment frame such as . At this time, the destination device number 33 in the acknowledgment frame stores “°01°” and the destination device number 34 stores “03”. 10 is received in step S29. From the source device number 33 in the received response frame, the calling side communication control device 101 can know the LAN device number of the called side communication control device 103. Once the route is determined, steps 529 and subsequent steps are not necessary for data transmission.

<Effects of the Third Embodiment> As described above, according to the third embodiment, the calling packets received from the X, 25 communication control unit 3 are sent to the LAN by simultaneous broadcast communication.
When the communication control device 10 that sends the call packet to all the above communication control devices 10 and the incoming DTE numbers in the calling packet match returns an acknowledgment frame, even if these numbers are different, the LA and N internal room numbers It is no longer necessary to manage a table that associates DTE numbers with DTE numbers, and the method for selecting routes for packets to be transmitted can be easily made by using the LAN function of simultaneous broadcast communication, which reduces the software load on the communication control device 10. At the same time, it is possible to easily expand the network.

[Effects of the Invention] As explained above, according to the network system of the present invention, it is possible to realize a network system that is flexible for easy route selection, system management, and system expansion, and also has a high degree of freedom in setting DTE numbers. This increases the number of connections and provides a more flexible network system.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the powerful concept of an embodiment according to the present invention; FIG. 2 is a diagram of a network system in which a plurality of packet-type terminals are connected to a LAN according to an embodiment via a communication control device 10; The figure is a block diagram showing the main configuration of the communication control device 10 of this embodiment, FIG. 4 is a diagram explaining the configuration of the RAM 4, and FIG. Figures 6(a) and 6(b) are diagrams showing the format of the LAN frame used in the LAN communication control unit 1 in this embodiment. Figure 7 is the route setting. 8 is a flowchart of the control procedure according to the first practical example, FIG. 9(a) is a flowchart of the control procedure according to the second embodiment, and FIG. 9(b) is a flowchart of the control procedure according to the second embodiment. DTE number and LAN in the second embodiment
A diagram explaining the relationship with the device number, Figure 10 (a) is the third
Flowchart of the control procedure according to the embodiment; FIGS. 10(b) to 10(d) are diagrams of the network system of the third embodiment, respectively; - Format diagram of transmission for broadcast communication (7M frame and acknowledgment frame) In the figure, 1... LAN communication control section 1.2... control section,
3...X, 25 communication control unit 3.4...RAM, 5.
ROM, 6... Device number setting section, 100... Communication medium, 101.102, 103, 104... Packet format terminal. Patent applicant Gyanon Co., Ltd. Figure 2 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 (b) 10th FIA (0)

Claims (3)

[Claims] (1) In a network system in which multiple packet-type terminals are connected to a local area network via a communication control device, DT of a calling packet for route setting
A part of the E number is a device number in the local area network for media access control, and the DT
A network system that establishes a link on a local area network using the device number obtained from an E number. (2) The network system according to claim 1, wherein the device number position in the DTE number is set within the communication control unit. (3) The network system according to claim 1, wherein the local area network system is a bus type or loop type local area network.