JPH0777375B2 - Bus connection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] According to the present invention, when a terminal device to which a predetermined packet switching method is applied is connected to a communication bus, a bus control device that controls the use of this communication bus is a control bus. The present invention relates to a bus connection system configured to give permission to use a communication bus via a bus.

[Conventional technology]

Conventionally, this type of bus connection system has an independent communication bus for each predetermined packet switching system, and only one system packet is transmitted to one communication bus.

That is, each terminal device connected to the communication bus receives the packet transmitted on the communication bus, checks the incoming call address indicating the destination, and when it matches its own address, this packet is regarded as a received packet to itself. Take in.

On the other hand, the structure of the communication packet formed and transmitted by each system is independent of each other, and the position of the incoming call address in the packet is designed independently for each system.

Therefore, it is not possible to connect terminal devices of different systems to the same communication bus, and a communication bus is provided for each system. For example, CCITT recommendation X.25 method, CCITT recommendation I series method, American IEEE (Institute of Electronics and Communication Engineers) 802 LAN (Local Area Network)
Each of the methods and the like forms a packet switching device with an independent communication bus.

[Problems to be Solved by the Invention]

As described above, the conventional bus connection system is configured to form and transmit a packet based on the regulation of the packet switching system that each terminal device is adapted to the communication bus. When the methods are mixed, a communication bus, which has been increasing in speed in recent years, is provided for each packet switching method, which is uneconomical in a small area.

An object of the present invention is to provide a bus connection method that solves the above problems by including a service identifier given to each packet switching method in one octet code at the beginning position of a packet transmitted on a communication bus. To do.

[Means for Solving the Problems]

The bus connection method of the present invention is a bus connection method in which a bus control device that controls the use of a communication bus that mutually connects terminal devices to which a predetermined packet switching method is applied gives permission to use the communication bus via a control bus. In; in each of the packet switching systems, a plurality of types of terminal devices to which a plurality of packet switching systems in which service identifiers corresponding to different packet protocols or formats are defined in advance are applied are accommodated in one communication bus. A line accommodating device to be connected; the line accommodating device; when receiving a packet transmitted from each of the plurality of types of terminal devices and transmitting the packet to the communication bus, one octet at the head position of each received packet The service identifier corresponding to each of the packet switching methods is added to the code area and transmitted. When the packet is received and detected from the communication bus, the service identifier is extracted from the octet code area at the head position of each received packet, and the packet switching method is individually applied to each of the plurality of types of terminal devices to be accommodated. When the service identifiers correspondingly set are collated and matched, the incoming call address of each received packet and the address set corresponding to each of the plurality of types of terminal devices accommodated are collated and matched. At this time, the received packet is transmitted to each of the plurality of types of terminal devices accommodated therein.

According to the bus connection method of the present invention by the above-mentioned means, even if a terminal device adapted to a different packet switching system is connected to one communication bus, the service identifier detected by the line accommodation device is a packet unique to each system. You can select and receive.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a functional block diagram showing an embodiment of the present invention. In FIG. 1, the line accommodation device 10 accommodates a terminal device 20 via a line and is connected to a communication bus 31. Also,
The line accommodation device 10 is a bus control device 30 that controls a communication bus 31.
To the control bus 32.

The line accommodation device 10 has a packet receiving unit 11, a service identifier adding unit 12, a packet transmitting unit 13, an interface unit 14, a packet detecting unit 15, a service identifier detecting unit 16, an address filter unit 17, and a packet transmitting unit 18. ing.

When receiving the packet transmitted from the terminal device 20, the packet receiving unit 11 notifies the service identifier adding unit 12 and the interface unit 14 of the reception of the packet. When receiving the packet reception notification from the packet receiving unit 11, the service identifier adding unit 12 takes in the packet received from the terminal device 20 and adds the service identifier corresponding to the packet switching system of the terminal device 20 to the head position of this packet. When the transmission permission is received from the interface unit 14, the packet transmission unit 13
Output to. The packet transmission unit 13 transmits the received packet to the communication bus 31. When the interface 14 receives a packet reception notification from the packet reception unit 11, it requests the bus control device 30 for transmission permission via the control bus 32, and when it receives the transmission permission, it notifies the service identifier addition unit 12 of this.
This series of operation procedures will be described later with reference to FIG.

The packet detection unit 15 always takes in the transmission code on the communication bus 31, and receives the control information indicating that the packet is sent to the communication bus 31 from the bus control device 30 via the control bus 32 and the interface unit 14. The packet is detected and transferred to the service identifier detection unit 16. The service identifier detection unit 16 detects one octet at the head position of the packet as a service identifier. The service identifier indicates the type of packet switching system, for example, CCITT recommendation X.25 system, CCITT recommendation I series system, IEEE defined 802 LAN system, and the like. When the service identifier detection unit 16 detects a preset service identifier, the service identifier detection unit 16 continues to receive the rest (packet encoding unit in FIG. 4).
Is transferred to the address filter unit 17 as one packet, and when it cannot be detected, the received packet is discarded.
The packet received by the address filter unit 17 has a packet switching system packet configuration suitable for the terminal device 20 to be connected, and the incoming call address is checked from a predetermined position as in the conventional case, and the address set in advance corresponding to the terminal device 20 to be accommodated. When it matches with the terminal device 20 via the packet sending unit 18.
Sent to, and discarded if they do not match. This series of operation procedures is shown in FIG.

Prior to the description of FIGS. 2 and 3, FIG. 4 will be described with reference to FIG.

FIG. 4 is a format diagram showing an example of a packet transmitted on the communication bus 31 of FIG. The above-mentioned service identifier is composed of 8 bits, is preset for each packet switching method, and is transmitted to the head of the packet on the communication bus 31 transmitted and received by the terminal device 20. The packet following the service identifier has a format defined by each service (packet switching method). Therefore, the terminal device including the packet receiving unit 11 and the address filter unit 17 of the line accommodation device 10
The functions on the 20 side are exactly the same as before.

Next, the operation procedure of the line accommodation device 10 for transmitting a packet to the communication bus will be described with reference to FIG. 2 and FIG. FIG. 2 is a flow chart showing an example of the calling procedure in FIG.

In the line accommodating device 10, when the packet receiving unit 11 receives a bucket from the terminal device 20 (procedure 101), the interface unit 14 receives a reception notification and receives a bus control device via the control path 32.
Request the use permission of the communication bus 31 to 30 (step 102). When the interface unit 14 receives the use permission of the communication bus 31 from the bus control device 30 (procedure 103), the service identifier adding unit 12 receives the use permission, drives the packet transmitting unit 13, and drives the communication bus. First, a predetermined service identifier is transmitted to the 31st octet position to 31 (procedure 104), then the packet defined by the service received by the packet reception unit 11 from the terminal device 20 is directly transmitted (procedure 105), and the transmission procedure To finish.

FIG. 3 is a flow chart showing an example of the incoming call procedure according to FIG. This will be described with reference to FIG. 3 and FIG.

In the line accommodating device 10, the packet detection unit 15 that examines the transfer code on the communication bus 31 receives the control information indicating that the packet from the bus control device 30 received via the interface unit 14 is transmitted to the communication bus 31. Start packet reception (step 11)
0), the received packets are sequentially transferred from the first octet to the service identifier detecting unit 16. The service identifier detection unit 16 investigates the first octet of the received packet (procedure 111), and when it matches and matches the preset service identifier corresponding to the terminal device to be accommodated (procedure 112), the subsequent octet code The reception (procedure 113) is continuously transferred to the address filter unit 17. Address filter section
17 examines the incoming call address at the given octet position (procedure
114), when the address is collated with a preset address corresponding to the terminal device to be accommodated (step 115), the communication bus 31
The packet in the storage (procedure 116) received from (the service identifier is removed as described above) is passed, and is transmitted from the packet transmission unit 18 to the terminal device 20 (procedure 117).

In this way, the line accommodation device can identify and take in the packet on the communication bus by the service identifier set for each packet switching method.

FIG. 5 is a block diagram showing how a plurality of types of lines are connected to a communication bus. As shown in the figure, a plurality of line accommodation devices 10-A connected to the communication bus 31 accommodate lines to which terminal devices conforming to the CCITT Recommendation X25 communication standard are connected, and the line accommodation device 10-B is recommended by CCITT. The line accommodating device 10-C of the I series accommodates a line to which a terminal device conforming to each communication standard of the IEEE defined 802 LAN is connected. The communication bus 31 may be used by a conventional method in which the bus control device 30 notifies the line accommodating devices 10-A to 10-C via the control bus 32.

Each of the line accommodating devices 10-A to 10-C adds a service identifier corresponding to the terminal device accommodated at the head position of the packet to be transmitted to the communication bus, and transmits the packet.
Since only the packet having the same identifier is taken in by looking at the service identifier, different types of lines can be simultaneously connected to one communication bus 31 without taking in different types of packets.

In the present embodiment, the line accommodating device is shown as a functional block in the description, but the functional block configuration and procedure such as packet storage and formation or identification of the identifier are not limited to the above description as long as they can exert an overall function. Not something.

〔The invention's effect〕

According to the bus connection system of the present invention, a plurality of types of terminal devices to which a plurality of packet switching systems in which service identifiers corresponding to different packet protocols or formats are defined in advance are applied are accommodated for each packet switching system. However, it has a line accommodating device connected to one communication bus, and when the line accommodating device receives packets sent from each of multiple types of terminal devices and sends them to the communication bus, one octet at the beginning of the received packet A service identifier corresponding to each packet switching method is added to the code area and transmitted, and when a packet is received and detected from the communication bus, the service identifier is extracted from the octet code area at the head position of the received packet, It is set for each packet switching method of each of the multiple types of terminal devices to be accommodated. When the service identifier is collated and matched, the incoming address of the received packet and the address set corresponding to each of the plurality of types of terminal devices to be accommodated are collated and matched. Even if terminal devices of different packet switching methods are accommodated and connected, a different service identifier for each packet switching method is added to each packet received from a plurality of terminal devices. Since the received packet can be classified by the identifier added to each packet on the receiving side, multiple packets of different packet switching methods can be connected to one communication bus at the same time, and the same system and hardware Since packet transfer service can be performed with ware, it is economical even in small areas The effect is obtained that kind services can be complex construction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a functional block diagram showing an embodiment of the present invention, and FIG.
1 is a flow chart showing an example of a procedure for transmitting to the communication bus in FIG. 1, FIG. 3 is a flow chart showing an example of a procedure for receiving from the communication bus in FIG. 1, and FIG.
FIG. 5 is a format diagram showing an example of a packet configuration transmitted on the communication bus shown in FIG. 5, and FIG. 5 is a system connection diagram of an embodiment of the present invention. 10 ... Line accommodation device, 12 ... Service identifier addition unit, 16
...... Service identifier detector, 20 ...... Terminal device, 30 ...... Bus controller, 31 ...... Communication bus, 32 ...... Control bus

Claims (1)

[Claims] 1. A bus connection system in which a bus controller for controlling the use of a communication bus interconnecting terminal devices to which a predetermined packet switching system is applied gives permission to use the communication bus via a control bus; A line accommodating device for accommodating a plurality of types of terminal devices to which a plurality of packet switching systems, each having a service identifier corresponding to a different packet format defined in advance, respectively, is applied, and which is connected to one communication bus. The line accommodating device; when receiving a packet transmitted from each of the plurality of types of terminal devices and transmitting the packet to the communication bus, the packet is placed in an area of one octet code at a head position of the received packet. The service identifier corresponding to each switching method is added and transmitted; the packet is transmitted from the communication bus. When reception is detected, the service identifier is extracted from the octet code area at the head position of the received packet, and the service set corresponding to each of the packet switching methods of each of the plurality of types of terminal devices to be accommodated. When the identifiers are collated and matched, the incoming address of the received packet and the address set corresponding to each of the plurality of types of terminal devices to be accommodated are collated and matched, the plurality of types of terminals to be accommodated. Transmitting the received packet to each of the devices;