JPS6155303B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a loop-shaped data highway device, which connects each concentrator by controlling the selection of control information to the device connected to the next stage based on the positional relationship between the concentrators. Concerning the method of carrying out.

In the conventional line concentrator connection system, a caller's end station makes a call to a specific line concentrator, and the line concentrator sends back a response depending on the availability of channels within the group. For this reason, when a busy response is received from the line concentrator, there is a drawback that connection cannot be established even if there is an empty channel in another line concentrator.

An object of the present invention is to provide a line concentrator with a circuit that selects control information to be sent to the next device based on the channel status within its own line concentrator group, thereby reducing the turnaround time when making a call. It provides a means of connection.

In the present invention, when a line concentrator receives a connection request signal, if there is an empty channel in its own line concentrator group, it sends a connectable response, and if all channels are busy, the last line concentrator sends a busy response; The line concentrator is designed to reduce the turnaround time at the time of connection by sending a connection request signal to the next stage device.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.
Terminal equipment ST ₁ , ST ₂ and line concentrator CST ₁ , CST ₂ ,...
A data highway system is constructed by connecting the CST _o in _a loop through a transmission path L through which signals propagate in the direction _of the arrow _{in the} figure. The line concentrators CST ₁ , CST ₂ , ... CST _o accommodate communication control devices _{CCP 1 ,} CCP ₂ , ... _{CCP o} , respectively.
It is connected to a host computer (not shown) through communication control devices CCP ₁ , CCP ₂ , . . . CCP _o . In this embodiment, two terminal stations ST ₁ and ST ₂ are connected, but it is of course possible to connect more terminal stations, and the number of line concentrators is one or more. It is also possible to do this.

Terminal device DTE _1a , DTE _2a and terminal device DTE _1b ,
Assuming that two types _{of terminal} equipment, DTE _{2b ,} and
It has the following.

For example, as shown in FIG. 2, the frame format sent to the transmission path L is a frame synchronization signal F,
It consists of a destination address field DA, a control information field C, a self address field SA, a header field H, a data field DATA, a frame check sequence signal FCS, and a frame synchronization signal F.

For example, from terminal device DTE _1a to communication control device CCP ₁
When making a call to the host computer connected to the terminal device DTE 1a, the terminal device ST ₁ uses the call information from the terminal device DTE _1a to set the group address A that uniquely corresponds to the interface channel group Ga in the destination address field DA. ₁ , and the terminal device in its own address section SA.
A frame containing an address A ₂ uniquely corresponding to the DTE _1a and connection request information in the control information section C is formed and sent to the transmission line L.

When concentrator CST ₁ receives this frame and identifies that it is addressed to its own station, that is, that it has an interface channel group Ga corresponding to address A ₁ , it sends the connection request information and group address.
A ₁ selects an empty channel in the interface channel group Ga, and sets the address A ₃ that uniquely corresponds to this empty channel to the header part H of the frame.
, and the terminal device that made the call to the other party's address section DA.
A frame is formed by placing the address A ₂ of the DTE _1a , the group address A ₁ in the self-address section SA, and information indicating an acknowledgment to the connection request in the control information section C, and sends it to the transmission line L.

When the terminal device ST ₁ receives this frame, it determines that the connection is completed using the channel corresponding to the address A ₃ in the line concentrator CST ₁ .

In addition, if there is no empty channel in the interface channel group Ga, and if the line concentrator CST ₁ is the last stage, information indicating a negative response to the connection request is sent to the control information section C, and information indicating a negative response to the connection request is sent to the destination address section DA of the terminal device.
The busy notification is performed by forming and transmitting a frame in which the address A ₂ of the DTE _1a and the group address A ₁ are placed in the self-address section SA.

On the other hand, if there is no empty channel in the interface channel group Ga and the concentrator CST ₁ is not at the last stage, the received frame is sent out as is, thereby causing the next stage concentrator CST ₂ to perform the same control.

An example of the configuration of the line concentrator of the present invention based on this premise is shown in FIG.

The operation will be explained below based on the figures.

When CST ₁ receives a connection request from the terminal equipment from transmission path 1, transmission path interface section (reception) 2
The address comparison circuit 6 compares the decoded partner address DA with the own station address stored in the address storage circuit 5, and the result is The information decoding circuit 7 is notified, and if a match notification is received, the information decoding circuit 7 decodes the control information part C in the received information, and if it is a connection request, it decodes each channel status detection circuit of all line groups. 8 and instructs the response information generation circuit 9 to generate response information. On the other hand, the destination address DA in the received information is sent from the address decoding circuit 4 to the line concentration group selection circuit 10, decoded by the line concentration group selection circuit 10, and notified to the corresponding channel state detection circuit 8 in one concentration group. The channel state detection circuit 8 notified from the information decoding circuit 7 and the line concentration group selection circuit 10 sends an instruction to enable or disable direct reading based on the state signals from each channel 11-1 to 11-n to the response information generating circuit 9 and switching. The instruction generation circuit 12 is sent. Response information generation circuit 9
generates response information having a control information section C depending on whether connection is possible or not and transfers it to the transmission information selection circuit 13 only when there is an instruction from the information decoding circuit 7. On the other hand, the switching instruction generation circuit 12 receives the match or mismatch signal from the address comparison circuit 6 and the channel state detection circuit 8.
Connection possible/unavailable notification and location information storage circuit 1
Information on whether or not it is the lowest line concentrator from 4 (the last one in the direction of signal propagation, CST _o in Figure 1)
Based on this, the transmission information selection circuit 13 sends the received information from the delay circuit 3 to the transmission path 16 via the transmission path interface section (transmission) 15, or
It instructs whether to send the response information from the response information generation circuit 9 to the transmission line interface section (transmission) 15. For example, if the concentrator group of all concentrators is busy, the concentrators from CST ₁ to CST _o-1 send the received connection request as is to the next concentrator,
A busy response is generated at CST _o and sent back to the calling terminal. Furthermore, if a channel in the concentration group of at least one concentrator is not busy, all concentrators (all of which are busy) above that concentrator CSTl will directly transmit the received connection request to the next concentrator as described above. The CSTl generates a connectable response and sends it back to the calling terminal. Therefore, in the connection fuse, the communication between the calling and called devices is based on requests,
Since only one response is required for each response, it is possible to reduce turnaround time, and if there is an empty channel in at least one of the multiple concentrators, it is possible to connect, allowing for efficient connection. It is.

As explained above, according to the present invention, when a line concentrator is used, connection can be made with one line concentrator having an empty channel among a plurality of line concentrators with a short turnaround time. It has the effect of reducing time.

[Brief explanation of the drawing]

FIG. 1 shows an example of an implementation configuration of the present invention, FIG. 2 is an explanatory diagram of a frame format, and FIG. 3 shows an example of the configuration of a line concentrator according to the invention. ST ₁ , ST ₂ ...Terminal equipment, CST ₁ , CST ₂ , CST _o
...Concentrator, DTE _1a , DTE _1b , DTE _2a , DTE _2b
...Terminal device, CCP ₁ , CCP ₂ , CCP _o ...Communication control device, Ga, Gb...Interface channel group, L...Transmission line, 1,16...Transmission line, 2,1
5...Transmission line interface unit, 7...Address decoding circuit, 9...Response information generation circuit, 12...
Switching instruction generation circuit, 13... Transmission information selection circuit.

Claims (1)

[Claims] 1 A plurality of line concentrators connected to a host computer via interfaces classified into predetermined groups and one or more end station devices to which a terminal device is connected are connected in a loop, and from the terminal device In a data highway device that connects the terminal device and a host computer by making a call to the line concentrator, the line concentrator receives a connection request signal from the terminal device and creates an empty space within its own interface group. If there is a channel, it returns a connection permission response to the terminal device, and if there is no free channel in its own line concentration group, it forwards the connection request signal from the terminal device to the next line concentrator. With,
A line concentrator connection system characterized in that if no free channel is found in any of the line concentrators, a busy signal is transferred from the final line concentrator to the terminal device.