JPS61177843A - Loop network system - Google Patents

Abstract

PURPOSE:To attain complete duplex communication between two nodes possible by providing a controlling field that retains right of transmission in own node after giving right of transmission to other nodes in addition to a token frame that controls shifting of right of transmission between nodes. CONSTITUTION:Master nodes A, B and slave nodes C-D are connected in looplike form by a transmission line 6. A token frame is sent from th node A or B to nodes C-E, and a node that acquired the frame obtains right of transmission to the master node. Each node holds receiving frame in a receiving frame buffer 27, and address of receiving station DA, address of sending station SA, a level mask M and a controlling field C in the frame in registers 16, 18. DA', SA', M' set in registers 16-18 by a controlling processor 30 are compared by comparators 19-21. When all comparators coincide, and duplex communication right retaining bit of the sending station of the field C is decoded 22, an AND circuit 23 opens and latches token receiving, and executes duplex communication with the master by the transmitting frame held in a transmitting buffer 28.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a token-controlled loop network system, and more particularly, to a loop network system suitable for controlling acquisition of transmission rights.

[Background of the invention]

In a token-controlled loop network system, a transmission right control frame called a token frame is transmitted to a loop transmission path to control the movement of transmission rights between a plurality of nodes connected to the loop transmission path. Conventionally, the protocol used to grant transmission rights to nodes by transmitting token frames gave the highest priority to the node connected closest to the node that sent the token frame, and In this method, the priority level bit is set in the token frame so that when the node receiving the token frame has the lowest priority, There is a known system in which the transmission right cannot be acquired unless the level of the frame that the user is trying to transmit is equal to or higher than the priority level of the token-frame.

By the way, in the conventional method described above, for example, when a channel device of a central processing unit and a high-speed input/output device are connected to a source network, and an attempt is made to control the input/output operations of the input/output device using commands from the channel device, the following occurs. Various problems arise.

Here, the node corresponding to the channel device will be referred to as a master node, and the node corresponding to the input/output device processing will be referred to as a slave node.

(1) Generally, at the level of frame transfer requests from slave nodes to master nodes, data transfer requests from electrical input/output devices, and reports of completion of input/output device operations;
There are reports of interrupt states that occur regardless of instructions from the master node, reports of abnormalities in input/output devices, etc.
A node needs to decide which level of transfer request it will accept from a slave node based on its own internal state and importance level. However, in response to such requests,
In the conventional method, the master node cannot freely select the level of the 0 (2) slave node.For a frame transfer request, the destination (master node) to be transferred is determined, and the master node - It is necessary to transfer frames only when the node is free. That is, it is necessary to acquire the transmission right only for frames to which the transmission right is granted from a determined master node. However, the conventional system does not have a function of selectively acquiring transmission rights, and is not suitable for control when a plurality of channel devices are connected to one loop.

(5) When making a high-speed data transfer request and transferring the data between a pair of master node and slave node, the conventional method in which only one node has the right to transmit in the loop Only heavy-duty communication is possible, and data transfer speeds cannot be increased.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a token-controlled loop network system that achieves functions equivalent to the conventional I10 interface performed by channel devices and input/output devices.

[Summary of the invention]

In order to achieve the above object, the present invention includes a token frame that controls the transfer of transmission rights between nodes, in which the transmission rights are reserved for the own node even after the transmission rights are granted to other nodes.
A control field is provided to suppress transmission from other nodes that have not acquired the transmission right, and a data link is established between the node that received the token frame and acquired the transmission right and the node that transmitted the token frame. is established, and data transmission and reception, that is, full-duplex communication is performed only between these two nodes.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

Figure 1 is a configuration diagram of the loop network system.
Nodes A to E are connected to a loop transmission line 6. Here, nodes A and B are master nodes (equivalent to channel devices), and nodes C and D.

Let E be a slave node (equivalent to an input/output device).

FIG. 2 is an example of the format of a token frame according to the present invention.
Delimiter field DBL that separates frames from time fill, which is special data for filling in between frames.
S, DELE, destination address field DA, source address field SA, level mask field M, control field C, and frame check sequence FC8. This token frame is sent from the master node A or B in the loop network and is received at the slave node C, Df or E to acquire the transmission right for the master node person or B who sent the token frame. . The slave node C, D or E, which has obtained the transmission right, transfers the frame to the master node A or BK that sent the token frame, and sends the token frame '4g1. Master node A or B also receives the transmission right from slave node C,
Transfer the frame to D or E.

This token frame is a token frame for slave nodes, and even if a certain slave node gains the right to transmit, the mask node does not lose the right to transmit. Furthermore, a slave node cannot transmit a token frame that grants transmission rights to other nodes.

FIG. 3 is a diagram showing an embodiment of the transmission/reception control section in the mask node and slave node. In Fig. 3, 11 is a serial/parallel conversion circuit, 12 to 15 are a receiving address (DA) and a sending address (DA) in a token frame.
SA), level mask (M), control field (C)
are the registers that are set. 16 to 18 are reception destination comparison addresses (DA') from the control processor 30;
Source comparison address (SA'), level comparison mask (M
There is also a register group in which o) is set. 19 to 21 are a group of comparison circuits, 22 is a decoder, 23 is an AND circuit, and 24 is a token reception latch. 25 is a control circuit, 26 is a time fill generation circuit for generating special data to fill in the space between frames, 27 is a receiving frame buffer, 28 is a transmitting frame buffer, and 29 is a selection circuit. A control processor 30 is used to control the entire master node and slave nodes.

Hereinafter, token control will be explained using an example in which slave node D receives a token frame transmitted from master node B, acquires the transmission right, and establishes linkage for full-duplex communication. The level mask field of the token frame consists of, for example, one byte, where bit 1 is the data transfer request level (level 1) and bit 2 is the input/output operation completion report level (level 2).

Since the other P/K are not related to the present invention, their explanation will be omitted.

Now, for example, when this system is started up, a token frame is sent to give master node AK the right to transmit, and master node A obtains the right to transmit. If there is no particular data to transmit, the master node person relinquishes his own transmission right to the master node BK and transmits a token frame that grants the master node BK transmission right. Even though the master node B obtains the transmission right using this token frame, when the master node B performs full-duplex communication with the slave node D, the following occurs.

Now, the master node B, which has the transmission right, transmits a token frame as shown in the format shown in Figure 2, for example, for the purpose of receiving and receiving a report on the completion of an input/output operation.

At this time, the master node B transmits the destination address (DA) of the token frame shown in FIG. 2 from the control processor 3o to the transmission frame buffer 28 via the signal line 40 in FIG.

Source address (SA), level mask (M).

In the control field (C), each slave node D
address, master node B address, bit 2 set to 1
``, and @1'' is set as control data that specifies a transmission right reservation instruction for full-duplex communication,
Further, the token reception latch 24 is set to 11'', which indicates a transmission right reservation instruction, and a token frame is transmitted from the transmission frame buffer 28 according to an instruction from the control circuit 25.

Now, the level mask field (M) of the token frame sent from master node B is shown in FIG.
As shown in a), bit 2 is '1' and the transmission right is granted to a slave node that has a report level request for completion of input/output operations.At this time, slave node C communicates with master node B. The data transfer request (, level mask register 14 request V level μ, (b
), bit 1 is @1''K.

In addition, the slave node D requests the master node B to report the completion of the input/output operation by setting bit 2 of the level mask register 14 to +1 as shown in (c)K of FIG.
“It’s getting worse.

The token frame sent from master node B is sent from transmission line 6 to master node A, but in master node A, the AND circuit 25 is not established and the token reception latch is in the state of ``0''. Therefore, the control circuit 25 instructs the selection circuit 29 to select the receiving 7-frame buffer 27, and transfers the token frame as it is to the slave node CK.

In the slave node C, the token frame input from the transmission path 6 is sequentially stored in the reception frame buffer 27&C, and at the same time, the bit serial data of this token frame is converted into serial byte serial data by the serial/parallel conversion circuit 11. is converted to The destination address field (DA), source address field (SA), level mask field (M), and control field (c) in this byte serial data KW converted token frame are each registered in register 12. ~15.

The data in the V raster 12 is a group address designated by a slave node, and here, for example, a group address including slave nodes C and D is designated. The data in register 13 indicates the address of master node B.

The data in the level mask register 14 is as shown in FIG. The destination comparison address (1)A'), the source comparison address (8A''), and the level comparison mask (M') are set.The data in register 16 indicates the group address of slave node C.Slave・Since node C holds a request (data transfer request) to master node B, the data in register 17 indicates the address of master node B. The data in register 18 is shown in FIG. 4(b) &C The top 1 shown is I11''.

The comparison circuit 19 is a circuit that compares the registers 12 and 16.
Check the slave node group to which you are granting transmit rights with the token frame. Comparison circuit 2
0 is a circuit that compares registers 13 and 17, and checks whether it is a master node to which transmission rights are to be granted. Further, the comparison circuit 21 is a circuit that compares the data in the registers 14 and 18 corresponding to pits, and checks the request level for granting the transmission and 1lji rights.The comparison circuit 19.2
0.21 outputs '1' when a match is found.

The decoder 22 decodes the data in the control field register 15 and outputs @1'' when the master node acquires the transmission right for the sent token frame.

The output of the comparison circuit 19.20121 and the output of the decoder 22 are input to the AND circuit 23, and the AND circuit 25 sets the token reception latch 24 if the AND condition is satisfied, and sets the token reception latch 24 if the AND condition is not satisfied. 24 is not set. At slave node C, the outputs of comparators 19 and 20 are 11'', and the output of decoder 22 is also ``1'', but since the output of comparator circuit 21 is @O1'', the token receiving latch 24 is not set. In this case, the control circuit 25 is the selection circuit 29
It instructs the receiver to select the receive frame buffer 27, and the token 77-m of the receive frame buffer 27 is sent to the transmission line 6 as is.

The token frame sent from the slave node C enters the slave node D, and similarly to the above-mentioned slave node C, the token frame is stored in the receive frame buffer 27 and is simultaneously transferred to the serial/parallel converter circuit 11. through its destination address field (DA), source address field (SA), level mask field) "CM), '/
IIJm field (C) is in registers 12 to 1, respectively.
Set to 5. The data in registers 12-15 are the same as for slave node C. - million, register 1
6 to 18, the control processor 30 sets the receiving destination comparison address (to D'') and the sending source comparison address (S), respectively.
A'), level comparison mask (M') is sectored, register 16 contains the group address of slave node D,
Register 17 indicates the address of master node B, and the data in register 18 has bit 2 @1'' as shown in FIG. The outputs of circuits 19 to 21 are all @1111, and the output of decoder 22 is also @1''
The token reception latch 24 is set to the set state @11'' by the AND circuit 25. As a result, the slave node D acquires the transmission right, and the selection circuit 29 of the control circuit 25
In response to an instruction to the VC, the data of the time fill generation circuit 26 or the data of the transmission frame buffer 728 (input/output operation completion report) is selected by the selection circuit 29 and sent to the transmission line 6.

When master node B terminates full-duplex communication with slave node D and needs to relinquish the transmission right, master node B relinquishes its own transmission right and also transfers the master node AIC transmission right. By sending a token frame to the master node, master node A can obtain the transmission right. The control of this control circuit 25 is shown in the flowchart of FIG. First, in step 31, it is detected based on the identification information whether a token frame has been received. If no token frame is received,
In step 57VC, the transmission of the time fill 26 is instructed. When the token frame is received, it is checked in step 521/C whether the condition for receiving the token of the node to which this control circuit 25 belongs is satisfied, that is, the state of the token reception latch.

If the condition for receiving this token is not met in step 32, the gate of the selection circuit 29 is opened in step 33 to transmit the data in the receive frame buffer 27.

Once the conditions for receiving the own node's token have been established in step 32, it is checked in step 34 whether or not there is data to be transmitted in the transmission frame buffer y28, and if there is no data to be transmitted, the time fill 26 is filled in step 36. Wait for the transmission data to be set in the transmission frame buffer 28, and step 3
When there is transmission data in the transmission frame buffer 28 in step 4, the data in the transmission 7 frame buffer 28 is transmitted in step 35. Transmission frame buffer 2
After transmitting the data of 8, in step 38,
If an instruction to suspend the transmission right of the own node has been given, that is, if the token reception latch 24 is set, the process moves to step 34, and if an instruction to suspend the transmission right of the own node has not been given, the token is immediately received. If the latch 24 is in the reset state, the process moves to step 31. next,
The data sent from slave node D to master node B is 1. Via the transmission line 6 shown in Figure i'3,
It is stored in the reception frame buffer 27 of the master node B, and the contents of the registers 12 to 15 are taken into the control processor 30 and processed for control. in this way,
Once the token receive latch 24 is set, the receive frame buffer 27 remains active until a selected token frame arrives from another node, or until the own node resets the token receive latch 24 by the controlling processor 30. The token frame is never sent (,
In addition, since a node that has not acquired the transmission right, that is, a node whose token reception latch is in a reset state, always transmits only the contents of the reception frame buffer 27, only the node that has acquired the transmission right can send arbitrary information to the master node. Frames of arbitrary size can be transmitted in a time of . At the same time, the received data can be sent to the master node via the control processor 50, and a full-duplex communication linkage can be established with the mask node.

Next, an example of full-duplex communication between master node B and slave node D will be explained with reference to FIG. First, a token claim (TKN) is sent from master node B (then slave node D receives a response frame (asp
) is returned.This response frame (R8P) also includes the status of the slave node D and the status of the data transfer request. When master node B receives this response frame (R8F), master node B transmits a data frame (D^TA1). On the other hand, slave node D
is busy, data request 7 for next data transfer request
Sends Req A (REQ2). When the transmission of master node B&MU data frame 1 (DATAI) is completed, transfer of data frame 2 (DATA2) is subsequently started. By repeating this operation, data can be transferred between master node B and slave node D using full-duplex communication.

〔Effect of the invention〕

As explained above, according to the present invention, in a token-controlled loop network system, it is possible to perform full-duplex communication with slave nodes at the level required by the master node, and the conventional I10 It is possible to realize a function equivalent to a data transfer request from an input/output device that is busy with an interface channel device.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a loop network system, Figure 2 is a diagram showing an example of the format of a token frame according to the present invention,
FIG. 3 is a diagram showing one embodiment of a mask node and a slave node, and FIG. tPS is a flowchart showing the control of the control circuit in FIG. 3, and FIG. 16 is a diagram showing an example of a transmission/reception sequence of communication between a master node and a slave node. A, B... Master node, C, D, E... Slave node, 19.20.21... Comparison circuit, 22... Decoder, 23-AND circuit, 24-)-Kun reception latch, 25... Control circuit, 26... Time fill generation circuit, 27... Reception frame buffer, 28... Transmission frame buffer, 29... Selection circuit, 50... Control processor.

Claims (1)

[Claims] 1. In a loop network system in which a plurality of nodes are connected in a loop through a transmission path, and frames are transmitted from an upstream node to a downstream node via the transmission path, at least one A node transmits a frame containing instruction information that instructs to grant transmission rights to other nodes, holds reservation information that suspends its own transmission rights, and receives frames transmitted from other nodes. , a first means for holding or releasing the suspended information according to the received frame; and a second means for determining whether or not the transmission right of the node is held or canceled based on the determination result of the second means and the instruction information, and in accordance with the suspension information. A loop network system characterized by comprising a third means for controlling whether the received frame is taken into the node or transmitted to a downstream node. 2. The loop network system includes a transmission frame buffer for storing transmission frames and a reception frame buffer for storing reception frames in each node, and the first means stores frames transmitted from other nodes in the reception buffer. A frame to be stored and transmitted to another node is stored in the transmission frame buffer, and the second
The means stores the frame transmitted from the first means in the reception buffer, and the third means stores the frame transmitted from the first means in the reception buffer, and the third means stores the content of the transmission frame buffer or the reception frame based on whether the pending information is held. 2. The loop network system according to claim 1, wherein the loop network system controls selectively transmitting the contents of the buffer. 3. The second means includes a reception destination address, a transmission source address, a level mask included in the frame, and a reception destination comparison address, a transmission source comparison address, and a level comparison mask held in advance in the node that received the frame. 3. The loop network system according to claim 2, wherein: 4. The loop network system according to claim 1, wherein each of the first and third means has a latch, and is controlled to hold or release the suspended information by the latch. 5. In the first means, the master node having the right to grant the transmission right transmits a frame containing instruction information for instructing the slave node to grant the transmission right, and holds reservation information for suspending the transmission right of the master node. receives a frame transmitted from the slave node, holds or releases the suspension information according to the received frame, and
The means receives the frame transmitted from the first means and determines whether the received frame is for the slave node, and the third means receives the determination result of the second means. and holding or releasing the transmission right of this slave node based on the instruction information, and controlling whether the received frame is taken into this slave node or transmitted to another slave node according to the suspension information. A loop network system according to claim 1, characterized in that: