JPH02260943A - Token passing device - Google Patents

Abstract

PURPOSE:To realize an inexpensive device without increasing much hardware by capturing a token when it is transmitted to a token passing device where a prescribed number of information frames are stored and preventing the other token device from transmitting the token to the token passing device. CONSTITUTION:A control part 15 decides whether the information frame has been stored in a storage memory 13 or not. Then, a decoder 12 is requested to capture the token. The token is captured while the information frame is transferred after the above-mentioned information frame is received. Thus, other nodes 1 and 3 cannot execute transmission while the token is captured by capturing the token while the information frame is transferred after the information frame is received. By using this point, the token is captured while the information frame is reception-processed even if there is no information frame that a self node transmits when the reception node whose reception capacity is low has received the information frame addressed to the self node. Thus, the information frame of the other nodes are prevented from being transmitted, and the token is transmitted when a reception processing terminates. Consequently, the number of times that a transmission source retransmits the information frame can be reduced.

Description

[Detailed Description of the Invention] [Summary] Regarding a token passing device that receives an information frame on a ring, stores the received information frame in a memory, and transfers the stored information frame to a host device, the information exchange efficiency is improved. a receiving means for receiving an information frame addressed to the token passing device itself; a memory for storing the received information frame; , and means for capturing tokens on the ring.

[Industrial application field]

The present invention is a local area network (hereinafter referred to as L
The present invention relates to a token passing device and method for controlling a token ring using a token passing method (abbreviated as AN).

[Conventional technology]

With the recent demand for flexibility in computer systems, there is a need for devices and methods that connect computer systems at high speed and exchange information more efficiently. For this reason, a token ring using a token passing method is provided.

FIG. 3 is a block diagram of the token ring, and FIG. 6 is an operation explanatory diagram for explaining beast token passing.

The conventional token ring is as shown in FIG. 3, with nodes 1. Node 2. A node 3 is provided. To prevent multiple nodes from transmitting information frames at the same time, a control frame called a token circulates on the ring, and only the node that captures this token
It becomes a transmitting node and can transmit information frames. In FIGS. 3 and 6, it is assumed that the node 1 holds the token 61 (FIG. 6(b)) and becomes the transmitting node 1.

Node 1 that wants to send an information frame captures the circulating token 61 (also called a free token),
The information frame is sent to the next node in the ring (information frame 62 in Figure 6). The receiving node always monitors the information frames circulating on the ring, takes in a copy of the information frame addressed to the own node, and circulates the information frame to the next node.

Referring to FIG. 6 below. Suppose that node 1 sends an information frame 62 to node 2. Thereafter, the node 2 captures the information frame 62 and transmits the information frame 62 to the node 3.

Node 3 determines that the information frame 62 is not addressed to itself, and transmits the information frame 62 to node 1.

When node 1 receives the information frame 62, it determines that it is the information frame 62 that it has transmitted, removes the information frame 62 from the ring, and transmits a token 63 to node 2.

As described above, tokens are circulated on the ring so that all nodes on the ring can communicate equally.

[Problem to be solved by the invention]

However, in the case of the token passing described above, the reception capability is low (that is, the speed at which the information frame is transferred to the upper level device after receiving the information frame is slow, or the speed at which the information frame is transferred to the upper level device after receiving the information frame is low). - the memory capacity to store information frames is small)
If a node exists, the following issues arise.

Node with low reception ability (temporarily referred to as node 2 in Figure 6)
If the previous information frame is being transferred to the higher-level information processing device, the next information frame cannot be received.

Node 3 receives token 63 (Fig. 6(a), (b))
Assume that the information frame 64 is received and the information frame 64 is transmitted to the node 2. The information frame 64 is sent to node 2 via node 1 on -1. Node 2 receives the information frame 64
determines that the frame is addressed to its own station, and must copy the frame 64, but since the speed of transferring it to the higher-level device is slow,
The previously received information frame 62 has not been transferred,
When there is no free space in the memory to temporarily store the information frame,
The information frame is returned to the link without being stored.

The information frame 64 is then sent to node 3, which erases the information frame 64 and token 65.
Send.

The node that has received the information frame returns a response frame to the information frame to the source node. If node 3 does not receive a response frame from node 2 within a predetermined period of time, it transmits the information frame to node 2 again. Figure 6 (a
) is the retransmitted frame 69. The node 2 can receive the retransmission frame 69 only after transferring the information frame 62 described above to the higher-level device.

In other words, when information frames are sent consecutively to a node with low reception capability, if that receiving node is processing the previous information frame, it will not be able to receive the next information frame, and the It is not possible to send a response frame to this node.

Therefore, since the response frame is not returned at the source node, the same information frame is transmitted (retransmitted) again.

If the other node is not in the process of receiving, a response frame for the information frame is returned and the exchange of information frames is completed. However, when the time interval between retransmissions is long, the exchange efficiency of information frames decreases. Furthermore, since the source node performs retransmission operations, the load increases. In order to solve the above problem, there are solutions such as using a high-speed transfer device and increasing the capacity of the storage memory where information frames are temporarily stored before being transferred to a higher-level device.
In either case, a large amount of hardware needs to be added, making it impossible to realize a low-cost device.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a token passing device that does not require the addition of a large amount of hardware, is low in cost, and does not reduce the efficiency of exchanging information frames.

[Means to solve problems]

In order to achieve the above object, the present invention provides a receiving means for receiving an information frame addressed to the token passing device itself;
The apparatus is configured to include a memory for storing the received information frames, and means for capturing a token on the ring when a predetermined number of information frames are stored in the memory.

[Effect]

When a predetermined number of information frames are stored in the memory, a token is transmitted to the token passing device in which the predetermined number of information frames are stored, and the token is captured and another token passing device transfers the predetermined number of information frames. Prevent the frame from being sent to the token passing device in which it is stored.

〔Example〕

FIG. 1 is a block diagram of a token passing device that is an embodiment of the present invention, FIG. 2 is a flowchart of a control program in FIG. 1, FIG. 4 is a configuration diagram of a frame, and FIG. FIG. 3 is an explanatory diagram of the operation of the passing device. The structure of the ring is similar to the [prior art].

Token passing device W100 installed on ring 1
are the information frames and people being transmitted on ring 1.
A receiver (hereinafter abbreviated as RV) 11 receives the message.

Transmission is performed from the driver 14 (hereinafter abbreviated as DV). The tokens and information frames received at the receiver 11 are sent to the decoder 12 and the start delimiters SD, ! of the tokens and information frames are sent to the decoder 12. 8 Ryo Delimiter ED (Figure 4)
determine the beginning and end of the frame and token.

The decoder 12 is an access control AC and determines whether the transmitted object is a token or an information frame. If it is a token, the control unit (consisting of MPU) 1
5 captures a token if there is a request for transmission from the host information processing device 18 here.

If what has been transmitted is an information frame, the decoder 12 decodes the information frame from the destination address DA of the information frame.
Determine whether it is directed to the own node.

If the information frame belongs to the own node, the information frame is transmitted to the control unit 15, and the control unit 15 copies the information frame to the storage memory 13. At the same time as the information frame is copied to the storage memory 13, it is transmitted again to the next node via the DVL 4 on the link.

The node that sent the information frame uses the decoder 12 to monitor the source address SA of the incoming information frame to see if it was sent by its own node, and if the information frame sent by its own node is sent. , the control unit 15 erases the information frame. That is, only the token is transmitted without transmitting the information frame.

Thereafter, the node that received the token can send. . The above token bancing control is the same as the conventional one.

The operation of one embodiment of the present invention will be described below.

Node 2 has a token passing device 100. Ring logic control/data flow control unit 16. It is composed of a host information processing device 18.

It is assumed that node 2 receives an information frame (FIG. 5 51) addressed to itself from node l. As described above, it is copied to the storage memory 13. It is assumed that the storage memory 13 has a capacity for one information frame.

The token passing device 100 of the node 2 is a DV14
sends an information frame 51 to node 3.

Since node 3 is not addressed to its own node, it is sent to node 1. Node 1 receives the information frame 51 sent by its own node.
is returned, the information frame 51 is deleted and the token 52 is transmitted.

After copying the information frame 51 to the storage memory 13, the node 2 performs reception processing, that is, transfer to the ring logic control/data flow control unit 16. The transfer destination is the memory of the ring logic control/data flow control unit 16 (hereinafter referred to as M
(abbreviated as S) is 17. The node 2 checks the frame check FC3 of the received information frame 51 to determine whether there are any errors in the data, and if there are no errors, transfers it to the ring logic control/data flow control unit 16. If there is an error, it is notified to the control unit 15 and the fact that there is an error is stored in the frame status FS. The ring logic control/data flow control unit 16 performs a protocol control session layer (management of synchronization and resynchronization between processes) based on the contents stored in the information I of the information frame 51.

Transport layer (controlling logical communication between nodes connected via multiple lines, ensuring reliable data transfer,
It guarantees the authenticity of data transfer through error detection/recovery procedures, etc. It also guarantees whether long data is sent and received correctly when it is divided into several pieces], and it manages the network N (communication route settings, etc.). It is something to do. In addition, the frame control FC of the information frame is used for ring purge, rebuilding the ring configuration (ring bypass), etc., and the frame status FS is used for transmitting error detection in the FC3,
It is used to detect double allocation of addresses, etc.

Now, in the node 2, the control program 20 is started while the information frame 51 is being transferred to the ring logic control/data flow control unit 6.

The process will be explained below using the flowchart in FIG.

FIG. 2 is an explanatory diagram of the processing of the control program.

Step 201 The control unit 15 determines whether the information frame 51 has been stored in the storage memory 13.

Step 202 Next, ask the decoder 12 to capture the token 52.

Step 203 Then, the information frame 51 is transferred to the ring logic control/data flow control section 16.

Step 204 Then, after the transfer is completed, it is determined whether the token 52 has been captured. If captured, step 205
．． If not, step 206 is executed.

Step 205 Return token 52 to the link.

Step 206 The request to the decoder 12 is canceled.

Step 207 finish.

Perform the above processing.

Therefore, by capturing the token during transfer of the information frame after receiving the information frame 51, the other nodes 1 and 3 cannot transmit while the token is captured.

In other words, this embodiment takes advantage of this point, and when a receiving node with low reception ability receives an information frame addressed to its own node, it can capture the token even if there is no information frame transmitted by the own node. By performing this during the frame reception process, the transmission of information frames from other nodes is suppressed, and the token is sent out when the reception process is completed.

This reduces the number of successive information frames during reception processing, and reduces the number of times the sender retransmits information frames.

In addition, even if a token is captured during reception processing, the time required to capture the token is shorter than the time required for retransmission as in the conventional case (normally, the information frame on the ring, the token transmission time, the ring Logic control/data flow control section 16
Transfer time to μ.

The exchange efficiency of information frames can be increased by reducing the number of retransmissions (because the host information processing device 18 retransmits the data after a predetermined period of time, approximately 1 second, in units of milliseconds). I can do it. Furthermore, since the number of retransmissions is reduced, the load on the nodes can be reduced.

The present invention has been described above according to examples. In the embodiment, the capacity of the storage memory 13 has been described as being equivalent to one information frame, but the capacity is not limited to this. When the capacity is two information frames, token capture processing can be performed when two information frames are stored in the storage memory. In the case of content IN, the process is performed when eight information frames are stored in the storage memory.

As shown above, the present invention can be modified in various ways according to the gist of the present invention, and the present invention does not exclude them.

(Effects) As mentioned above, even if there is a receiving node with low reception capability on the ring or the ring usage efficiency decreases, the recurrence of information frames is significantly reduced, so the efficiency of host-to-host information exchange increases. .

[Brief explanation of drawings]

FIG. 1 is a block diagram of a token passing device that is an embodiment of the present invention, FIG. 2 is a flowchart of the control program in FIG. 1, FIG. 3 is a block diagram of a token ring, and FIG. 4 is a frame FIG. 5 is an explanatory diagram of the operation of the token passing device, and FIG. 6 is an explanatory diagram of the conventional technology. 1...Link 11...Receiver 12...Decoder 13...Storage memory 14...Tribae 5...Control unit (MPU) 20...Control program misfire September - Lol Application 70 Tsukku Diagram'Dormitory 1 Diagram'jJE枦1 f) Kositrol Blog (Kinto Fronaya) ID Rageshi 2 Just look at the token dormitory! ! (4 pieces, 7 pieces (a) Token I) Pobe 1 Otsu (d le) f Koken Frey Atsu #) Door d name frame 艷 1 collection) 4 pieces

Claims (1)

[Scope of Claims] In a token passing device that receives an information frame on a ring, stores the received information frame in a memory, and transfers the stored information frame to a host device, the token passing device itself receiving means (11, 12) for receiving information frames addressed to the station; a memory (13) for storing the received information frames; and when a predetermined number of information frames are stored in the memory (13); , means (15, 20) for capturing tokens on a ring.