JPH0650870B2 - Throttling network system - Google Patents

Description

DETAILED DESCRIPTION [Outline] In a throttling network, a communication control device on a transmission side transmits an inquiry packet indicating whether or not a reception is possible to a communication control device on a reception side before data transmission, and communication control on the reception side is performed. The device adds the acceptability information to the inquiry packet and transfers it, and the communication control device on the sending side analyzes the rounded inquiry packet and starts communication only when the communication control device on the receiving side can receive. As a result, it is possible to prevent message congestion in the communication control device on the receiving side and prevent deterioration of communication efficiency.

[Industrial application field]

The present invention relates to improvement of an access control method in a communication network in which a plurality of communication control devices are connected by a ring transmission line.

The communication network targeted by the present invention is a communication network for the purpose of exchanging data between a plurality of distributed terminal devices or computers (hereinafter collectively referred to as terminal devices), a so-called local area network (LAN). A plurality of communication control devices each accommodating one or more terminal devices are connected by a ring transmission line, and each communication control device shares a plurality of slots that are time-divisionally transmitted in one direction on the transmission line. It is a so-called throttling network that communicates with each other.

This type of communication network has the advantages that the configuration of each communication control device is simple and that high-speed, high-efficiency communication is possible, but communication that exceeds the processing capacity of a specific communication control device is possible. May be concentrated.

[Conventional technology]

FIG. 5 is a diagram showing an example of a communication network to which the present invention is applied, FIG. 6 is a diagram showing an example of a packet configuration used in FIG. 5, and FIG. 7 is a conventional communication control device. It is a figure which shows an example.

In FIG. 5, five sets of communication control devices (N) (hereinafter referred to as communication nodes 2) each accommodating a terminal device (marked with a circle in the figure) and one set of monitoring nodes (SV) 3 are used as transmission lines. Four
Are connected in a loop by.

As shown in FIG. 6, the transmission path 4 has a predetermined time length and is time-divided into a plurality of slots SL repeated at a predetermined cycle (frame F). When the frame header FH indicating the start time point is periodically sent to the transmission line 4, the frame header FH goes around the transmission line 4 and each communication node 2, and again the monitoring node 3
Will be returned to.

Each communication node 2 detects the frame header FH arriving from the transmission path 4 and identifies the time position of each slot SL.

Each slot SL is composed of a control information portion C, a reception address DA, a transmission address SA (these are collectively referred to as a packet header PH) and data DT, as shown in FIG.
Further, in the control information section C, there is provided vacancy information B indicating whether or not the slot SL is in use.

Communication node 2 that requires communication with another communication node 2
Monitors the air-defense information B of each slot SL,
Occupy the slot SL indicating the empty state, and set the required address and data in the required reception address portion DA, transmission address portion SA and data portion DT to perform communication.

In FIG. 7, when a communication request from the accommodated terminal device 1 to the terminal device 1 accommodated in another communication node 2 and a transmission message are transmitted to the terminal interface (TIF) 201, a transmission / reception control unit (MPU) Reference numeral 212 denotes a data transmission buffer (D
SB) 202, and then packet assembly unit (PAS)
Request to send to 203.

The packet assembling unit 203 divides the transmission message accumulated in the data transmission buffer 202 into data DT that can be stored in one slot SL, sets the address given to the own communication node 2 as the transmission address SA, and sets the other communication node. The address assigned to No. 2 is used as the reception address DA, and the empty / occluded information B is closed to form the data packet DP with the control information section C.

The packet header analysis unit (PHA) 207 receives and analyzes the packet header PH of each slot SL arriving from the transmission path 4 via the receiver (RCV) 206, and the free / busy information B included in the control information unit C is empty. Slot S indicating status
When L is detected, the selector (SEL) 204 is set on the packet assembling unit 203 side, and the data packet DP assembled by the packet assembling unit 203 is detected as the detected empty slot S.
After being inserted in L and transmitted to the transmission path 4 via the driver (SND) 205, the selector 204 is set again on the packet header analysis unit 207 side.

The data packet DP circulates around each communication node 2 via the transmission path 4.

In each communication node 2, the packet header analysis unit 20
7 analyzes each slot SL as described above, further analyzes the reception address DA for the slot SL in which the empty block information B indicates the block state, and since it does not match the own address except for the destination node 2, the selector 204 And driver 205
To the transmission path 4 via.

In the destination node 2, the received address DA matches its own address, so the packet header analysis unit 207 activates the packet disassembly unit (PDA) 208.

The packet disassembly unit 208 disassembles the data packet DP received via the receiver 206 and stores the data DT in the data reception buffer (DRB) 209.

The originating node 2 waits until all outgoing messages have been sent.
The data packet DP is constructed by the above process and is transmitted to the destination node 2 through the empty slot SL.

In the receiving node 2, when all the data DT forming the transmission message have been received, the transmission / reception control unit 212
Data D stored in the data reception buffer 209
Compose a send message from T, terminal interface 2
It is transferred to the terminal device 1 via 01.

If a request to send a message to the same communication node 2 is issued to a plurality of communication nodes 2, each transmission node 2
Respectively occupy the empty slot SL as described above and transfer the data packet DP having the same reception address DA.

In the destination node 2, the data DT transferred from the plurality of source nodes 2 are indiscriminately and sequentially transferred to the data reception buffer 2
Since the data is stored in 09, each data DT forming the transmission message from each transmission node 2 is mixed and it becomes impossible to faithfully reproduce each transmission message.

[Problems to be solved by the invention]

As is clear from the above description, in the conventional access control method, the data packet DP can be transmitted in parallel from the plurality of source nodes 2 to the same destination node 2, and the data DT transmitted from each source node 2 can be transmitted. Mixed,
There was a problem that each transmitted message could not be faithfully reproduced.

In order to prevent such a defect from occurring, each data packet D
The packet header analysis unit 207 identifies the transmission address SA assigned to P, and the packet decomposition unit 208 separates the data DT into transmission address SA fields based on the identification result and stores them in the data reception buffer 209 for transmission / reception control. It is considered that the unit 212 composes a message for each transmission address SA, but the packet header analysis unit 207
It is necessary to add the identification function of the transmission address SA to
Further, since the data reception buffer 209 is divided into areas corresponding to the respective transmission addresses SA, there is a possibility that the storage ease will be increased.

Also, prior to the transfer of the data packet DP, the sending node 2
It is also considered that only the originating node 2 which has succeeded in setting starts the transmission of the data packet DP after confirming whether or not the communication channel can be set up based on a predetermined procedure between the receiving side and the receiving node 2. Setting processing and communication channel releasing processing are required before and after the message is transmitted, and the communication efficiency of the communication network may be reduced unless the message length is sufficiently long.

[Means for solving problems]

As shown in FIG. 1, according to the present invention, a plurality of communication control devices are connected in a ring shape through a transmission line, and on the transmission line, at least an empty space, a closed display portion, a transmission / reception address portion, and a data portion are present. In a throttling network in which a plurality of slots are arranged in a time-division manner and repeatedly circulate in a predetermined cycle, a reception enable / disable unit is added to each slot,
In addition, the communication control device has, in addition to the function of sending or receiving the empty or empty of the circulating slot, the identification of the receiving address, the transmission and reception of data,
Prior to data transmission, the empty block display section is closed to inquire about the reception availability of the communication control device on the receiving side in an empty slot among a plurality of circulating slots, and the reception availability section is set as a display corresponding to the inquiry, and transmission / reception is performed. Inquiry packet transmitting means for inserting an inquiry packet having an address set therein and transmitting it to the transmission line, and an inquiry packet receivable / non-receivable unit when it detects that the inquired packet that has circulated is for its own device. Upon receipt of the inquiry packet from the communication permission / inhibition information attaching means and the own device, which adds information indicating whether the reception is possible or not, the information in the reception availability section of the inquiry packet is identified,
This is solved by providing a communication propriety identifying means for determining whether communication is possible or not based on the identification result.

[Action]

In the communication control device 2 on the originating side, the inquiry packet transmitting means 100 creates an inquiry packet for inquiring the communication control device 2 on the receiving side whether communication is possible, and sends it to the transmission path 4.

In the communication control device on the receiving side, the communication permission / inhibition information addition means 200 adds information indicating the communication permission / inhibition to the inquiry packet for the own device which circulates on the transmission path 4.

The inquiry packet to which the communication permission / inhibition information is added goes around the transmission line 4 and is returned to the communication control device 2 on the originating side.

In the communication control device 2 on the calling side, the communication permission / inhibition identifying means 300 identifies the communication permission / inhibition of the communication control device 2 on the reception side based on the inquiry packet returned after making a round of the transmission path 4, and the communication is determined based on the identification result. Determine the start.

Therefore, if the communication control device on the called side adds and returns information indicating that communication is possible only to the inquiry packet transmitted from the communication control device on the specified sending side, the data from multiple communication control devices will be returned. It is possible to prevent the reproduction of the message from being impossible due to a mixture of. Further, the communication control device on the transmission side confirms whether or not the communication control device on the reception side is receivable when the transmitted inquiry packet makes a round trip through the transmission line and each communication control device and is returned. It is also possible to prevent a decrease in communication efficiency.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows a communication control device according to an embodiment of the present invention.
FIG. 3 is a diagram showing an inquiry packet according to an embodiment of the present invention, and FIG. 4 is a diagram illustrating a transmission process of the inquiry packet. The same reference numerals denote the same objects throughout the drawings. The target communication network is as shown in FIG.

In FIG. 2, a control packet transmitting buffer (CSB) 213 is provided as the inquiry packet transmitting means 100, a control packet receiving buffer (CRB) 216 is provided as the inquiry packet returning means 200, and a communication availability identifying means is further provided. Change detection unit (CHB) 2 as (300)
15 and a timer (TM) 214 are provided.

In addition, the inquiry packet QP shown in FIG. 3 indicates, in addition to the air-blocking information B in the control information section C, whether the receiving node can receive (logic “1”) or receive distortion (logic “0”). Information R is provided.

2 to 4, a communication request from the accommodated terminal device 1 to the terminal device 1 accommodated in another communication node 2,
When the transmission message is transmitted to the terminal interface 201, the transmission / reception control unit 212 stores the transmission message transmitted from the terminal device 1 in the data transmission buffer 202, and the control packet transmission buffer 213 stores the reception permission / prohibition information R in the logic. After accumulating the inquiry packet QP set to “0”, the packet assembling unit 203 is requested to transmit the inquiry packet QP.

Further, the packet header explanation unit 207 detects the arrival of the empty slot SL from the transmission line 4 in the above process, and selects the selector 2
04 is set on the packet assembling unit 203 side, and at the same time,
The control packet transmission buffer 21 is provided in the packet assembling unit 203.
The inquiry packet QP stored in
4 and the driver 205 to send it to the transmission line 4, and start the timer 214.

The inquiry packet QP goes around each communication node 2 via the transmission path 4.

In each communication node 2, the packet header analysis unit 20
7 analyzes each slot SL as described above, further analyzes the reception address DA for the slot SL in which the empty block information B indicates the blocked state, and analyzes the slot SL in which the inquiry packet QP is inserted. Since it does not match its own address except for the receiving node 2, it transfers it to the transmission line 4 via the side bit inversion unit 211, the selector 204 and the driver 205.

In the destination node 2, when the packet header analysis unit 207 analyzes the slot SL in which the inquiry packet QP is inserted, the received address DA matches its own address.
The packet header analysis unit 207 activates the packet decomposition unit 208.

The packet disassembly unit 208 uses the control packet reception buffer 2
When the inquiry packet QP is not accumulated in 16,
The own node 2 determines that the message can be received, and stores the inquiry packet QP in the control packet reception buffer 216. At the same time, the packet header rewriting unit 210 rewrites only the receivability information R of the inquiry packet QP in the bit inverting unit 211 from logical “0” to logical “1”, and the selector 20
4 and the driver 205 to the transmission line 4.

On the other hand, the receiving node 2 is already receiving a message from another communication node 2, and the control packet receiving buffer 216
If the inquiry packet QP is already stored in the packet, the packet decomposing unit 208 newly receives the inquiry packet QP.
Is not stored in the control packet reception buffer 216, the packet header rewriting unit 210 causes the packet header analysis unit 207 to
Does not rewrite the inquiry packet QP that has been received.

Therefore, the transmission / reception control unit 212 is
The inquiry packet QP received by 07 is transferred to the transmission path 4 via its side, the bit inverting unit 211, the selector 204 and the driver 205.

The inquiry packet QP is sent to the communication node 2 via the transmission line 4.
Or the received address DA does not match its own address in each communication node 2,
Is transferred until.

In the source node 2, the inquiry packet QP arrived from the transmission path 4 is transmitted to the packet header analysis unit 207 via the receiver 206.

The packet header analysis unit 207 analyzes the inquiry packet QP, and when it determines that the inquiry packet QP that has already been transmitted is returned from the reception address DA and the transmission address SA, the reception permission information R is transmitted to the change detection unit 215. To do.

The change detection unit 215 transmits the interrupt signal I to the transmission / reception control unit 212 when the receivability information R is set to logic “1”.

Upon receiving the interrupt signal I, the transmission / reception control unit 212 determines that the receiving node 2 can receive the message, and requests the packet assembling unit 203 to transmit the message stored in the data transmission buffer 202.

Thereafter, the message is transmitted from the source node 2 to the destination node 2 by the data packet DP by the same process as described above.

On the other hand, when the reception enable / disable information R is a logic “0”, the change detection unit 215 does not transmit the interrupt signal I.

When the timer 214 detects the passage of a predetermined time without receiving the interrupt signal I, the transmission / reception control unit 212 determines that the receiving node 2 cannot receive the message,
After the lapse of a predetermined period, the inquiry packet QP is transmitted again and repeated.

In FIG. 4, communication nodes 2-1, 2-3 and 2-
4, it is assumed that transmission requests to the same communication node 2-5 are simultaneously generated and the communication node 2-5 is in a communicable state.

In such a case, the originating nodes 2-1, 2-3 and 2-4
Respectively set the reception address DA to the address N5 of the communication node 2-5 and the transmission address SA to each communication node 2-.
Addresses N1, N3 and N of 1, 2-3 and 2-4
Inquiry packets QP1, QP3, and QP4 of 4 are transmitted.

When the inquiry packets QP1 and QP3 and QP4 are transmitted in the clockwise direction through the transmission line 4, first, the transmitting node 2-
The inquiry packet QP1 transmitted by 1 arrives at the destination node 2-5, and the inquiry packets QP3 and QP4 transmitted by the origination nodes 2-3 and 2-4 subsequently arrive.

At the destination node 2-5, the inquiry packet QP is first sent.
1 is received, the control packet reception buffer 216
Since no inquiry packet QP is stored in the packet, the reception enable / disable information R is rewritten to a logical "1" and sent to the transmission line 4. Since the combined packet QP1 is stored in the control packet reception buffer 216, it is sent to the transmission line 4 without rewriting the logical value of the reception permission information R.

Each inquiry packet QP1, QP3 and QP4 has a transmission line 4
And is returned to each of the originating nodes 2-1, 2-3 and 2-4.

At the source node 2-1, since the inquiry packet QP1 in which the receivability information R has been rewritten to the logical "1" is returned, the transmission of the data packet DP is started, but the source nodes 2-3 and 2-4. In (1), since the inquiry packets QP3 and QP4 of the side of which the receivability information R is logical "0" are returned, the transmission of the message is suspended.

Therefore, in the receiving node 2-5, the transmitting node 2-
Only the data packet DP from 1 is received and the data D
Since T is stored in the reception buffer 209, the transmission node 2
The transmitted message from -1 is faithfully reproduced.

As is clear from the above description, according to the present embodiment, the originator node 2 simply returns the inquiry packet QP transmitted prior to the transmission of the message through the transmission path 4 once.
Since the communication availability of the terminating node 2 is promptly determined, and the data packet DP is started to be transmitted only when the terminating node 2 is capable of receiving, the terminating node 2 can faithfully reproduce the message transmitted from only the particular communication node 2. It will be possible.

It is to be noted that FIGS. 2 to 4 are merely examples of the present invention, and, for example, the number of communication control devices constituting the communication network, the configuration of each communication control device (N) 2 and the configuration of various packets are described. The present invention is not limited to the illustrated one, and many other modifications can be considered, but the effect of the present invention does not change in any case.

〔The invention's effect〕

As described above, according to the present invention, in the communication network, the communication control device on the receiving side allows the transmission to only one communication control device on the transmitting side quickly at the same time, so that the transmitted message can be faithfully reproduced, Moreover, it is possible to prevent a decrease in communication efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing the principle of the present invention, FIG. 2 is a diagram showing a communication control device according to an embodiment of the present invention, and FIG. 3 is an inquiry according to an embodiment of the present invention. FIG. 4 is a diagram showing a packet, FIG. 4 is a diagram illustrating a transmission process of an inquiry packet, FIG. 5 is a diagram showing an example of a communication network to which the present invention is applied, and FIG. 6 is a packet used in FIG. 7 is a diagram illustrating an example of the configuration of FIG. 7, and FIG. 7 is a diagram illustrating an example of a conventional communication control device. In the figure, 1 is a terminal device, 2 is a communication control device (N),
3 is a supervisory control device (SV), 4 is a transmission line, 100 is an inquiry packet transmitting means, 200 is an inquiry packet returning means, 2
01 is a terminal interface (TIF), 202 is a data transmission buffer (DSB), 203 is a packet assembling unit (P
AS), 204 is a selector (SEL), 205 is a driver (SND), 206 is a receiver (RCV), 207 is a packet header analysis unit (PHA), 208 is a packet decomposition unit (PDA), and 209 is a data reception buffer (DR).
B), 210 is a packet header rewriting unit (PHC), 21
1 is a bit inversion unit, 212 is a transmission / reception control unit (MPU),
213 is a control packet transmission buffer (CSB), 214
Is a timer (TM), 215 is a change detector (CHD), 2
Reference numeral 16 is a control packet reception buffer (CRB), and 300 is a communication propriety identifying means.

Claims (1)

[Claims] 1. A plurality of communication control devices are annularly connected via a transmission line, and on the transmission line, a plurality of slots each having at least an empty space, a block display portion, a transmission / reception address portion, and a data portion are time-divisionally shared. In a throttling network that is arranged and revolves repeatedly at a predetermined cycle, each slot is provided with a reception enable / disable unit, and the communication control device is provided with whether or not the revolving slot is empty or not, sending, identifying a receiving address, and transmitting / receiving data. In addition to the function, prior to data transmission, the empty block display section is closed to inquire the receiving side of the communication control device to the empty slot of the multiple circulating slots, and the reception enable / disable section is set to the display corresponding to the inquiry. , An inquiry packet transmitting means for inserting an inquiry packet in which a transmission / reception address is set and transmitting it to a transmission line, and an inquiry packet circulated is for its own device When an inquiry packet is received, the inquiry packet is received when the inquiry packet is received from the communication enable / disable information adding means for adding information indicating whether the packet is receivable or not to the reception enable / disable section of the inquiry packet. A throttling network system, comprising: a communication propriety identifying means for discriminating the information in the receivable / impossible part and determining whether the communication is possible or not based on the identification result.