JPS6268339A - Token control system - Google Patents

Abstract

PURPOSE:To obtain a token control system not causing a fault attended with the missing of a reply frame by sending a token frame after reply frame sending independently of the reply region after each node sends the information frame sent from its own node and addressed to its own node. CONSTITUTION:When the information frame sent attended with the acquisition of transmission right is a frame addressed to its own node, a logic layer decides a frame addressed and sent to its own node ahead the preparation of transmission, functions the sequence control in advance to set the procedure in the order of the transmission instruction of the reply frame and the transmission instruction of a token frame. Then a signal G inhibits the 1st token frame transmission control and follows the token frame transmission instruction from the logic link layer given through a signal line F and then a signal line C. The logic link layer applies the transmission instruction of the reply frame after the reception of the information frame addressed and sent to/from its own node to apply the token frame transmission instruction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a ring network system that uses token passing as an access method, and particularly to a token frame transmission control method thereof.

[Background of the invention]

The conventional token frame transmission control method releases the transmission right immediately after sending an information frame after a certain period of time so that the information frame receiving node can insert a response frame. It is known that the time it takes for a response to be returned is the loop cycle time, and it is possible to monitor for one hour (Information Processing Society of Japan Distributed Processing Systems Research Group Material 23-7.1)
984° 7.20rX Speed Optical Fiber Loop Data Link Protocol Test"). In response monitoring, the time from the transmission of the information frame to the reception of the response frame is monitored.

However, in the past, when the information frame was addressed to itself, the response frame transmission time was determined by the number of nodes connected to the ring and the node delay time (usually about 2 bytes and 71 nodes), as shown in Figure 1. There are three types of token frame transmission times.

In FIG. 1, (a) is a case where a response frame is received in the response area, and when an information frame other than the one addressed to the volunteer is sent, or when the delay time is smaller than the response area, the response frame A in the received frame and token frame T
The time relationship is like this.

FIG. 1(b) shows a case where the response area and delay time almost match, and the token frame or response frame disappears.

FIG. 1C shows a case where the delay time is large compared to the response area, and the transmission frame sequence is the token frame T and the response frame A. At this time, the response frame A is
This is J! The token frame T is supposed to be relayed by all nodes other than the one that sent it, but the token frame T is captured by the other nodes.

A node that has acquired the right to transmit may erase a response frame by transmitting an information frame.

It is not a special measure to make the response area larger than the relationship with throughput, and in the past, when the response frame was erased in Figures 1(b) and (c), even if no hardware failure occurred, No consideration was given to the fact that failures would always be reported by response monitoring regardless of the situation.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the conventional drawbacks, an object of the present invention is to provide a token control method that does not cause failures due to disappearance of response frames when sending out information frames having addresses addressed to the sender.

[Summary of the invention]

In FIG. 2, 1 is a node processor, 6 is a channel, and when an information frame 23 addressed to itself is transmitted to the loop transmission line 20, the reason why the response frame 22 disappears is that after the information frame 23 is transmitted. In the transmission frame sequence, a token frame 21, a response frame 22
Or.

This is because there are cases where the timings of both transmissions coincide.

When the information frame 23 having an address other than the original address is sent, the response frame 22 cannot be lost as shown in FIG. This means that the token frame 21 is
This is because it never overtakes the response frame 22. Therefore, after each node sends the self-addressed information frame 23, it is sufficient to send a token frame after sending the response frame 22, as shown in FIG. 1(a), regardless of the response area.

[Embodiments of the invention]

Examples of the present invention will be described in detail below. FIG. 3 shows the layer division of the node processor 1 according to this embodiment. An optical fiber is used for the transmission line 20, and the physical layer 2 has optical-electrical (electrical-optical) conversion and encoding/decoding functions. Medium access layer 3 is for frame transmission and reception and its control.

Has failure detection and buffer functions. Logical link layer 4
has a failure recovery function and a command decoding function, and the channel control unit 5 is an interface unit between the node processor 1 and the channel 6.

FIG. 4 shows the frame structure. The frame is surrounded by DEL. Each node processor decodes the frame contents at the medium access layer and determines whether to receive the frame. In the figure, LC indicates each frame type: token frame, information frame, and response frame. ■
is a field inserted only in an information frame.

FIG. 5 shows a block diagram of a medium access layer that performs control specific to this embodiment. The frame receiving section 7 includes DA, SA, LC, and FCSL.

Perform deciphering of 2. Receive DMA II is the buffer control section of the information field. The timer control/failure detection unit controls timers for monitoring the loop-reverse time of the token frame and for monitoring the response frame reception time after sending the information frame, detects a failure by the timer timeout, and sends it to the upper interface unit. It reports to logical link layer 4 through I2. The frame transmitter 10 transmits frames in accordance with the frame type instructed by the frame transmitter controller 9. When sending an information frame.

Information from transmit DMA 1'3 is placed in 1 field.

Here, the frame transmission control section usually determines the transmission frame type based on the reception frame type or the timer 11 out. Focusing on token frame transmission, first, after acquiring the transmission right by receiving a token frame, an information frame is transmitted, and after a certain period of time, a token frame is transmitted.
Give up the right to send. Second, when the loss of the token is confirmed by the timeout of the transmission right monitoring timer, a token frame addressed to itself is sent in order to recover the transmission right.

However, in this embodiment, a third token frame transmission control method is newly adopted. If the information frame to be transmitted upon acquisition of the transmission right is a self-addressed frame, the logical layer determines that it is a self-directed self-addressed frame before preparing for transmission.
The order control is activated in advance, and settings are made so that the response frame transmission instruction and the token frame transmission instruction are given in this order.

Then, the signal G sends the first token frame (
B control is prohibited, and the token frame transmission instruction from the logical link layer in FIG. 3 given by signal line F and further signal line C is followed. After receiving the self-addressed information frame, the logical link layer instructs to transmit a response frame, and then instructs to transmit a token frame.

Note that it is also possible to perform token frame control equivalent to the above embodiment within the medium access layer 3. In this case, the information that sent the self-addressed information frame is transmitted to the signal G'
In this case, it is only necessary to perform automatic control to transmit the token frame after transmitting the response frame.

〔Effect of the invention〕

According to the present invention, even when transmitting a self-addressed information frame,
Since the order of the response frame for the self-addressed information frame and the token frame sent out along with the information frame transmission is not reversed on the loop, problems associated with the disappearance of the response frame when sending the self-addressed information frame, which were seen in conventional methods, can be avoided. This has the effect that it does not occur.

[Brief explanation of drawings]

Figure 1 is a diagram showing transmission frames and reception frames of a node processor that has transmitted an information frame addressed to itself using the conventional control method, Figure 2 is a timing chart for transmitting a response frame and a token frame when transmitting an information frame addressed to another, and Figure 3 4 is a diagram showing layer division in an embodiment of the present invention, FIG. 4 is a block diagram of a frame configuration, and FIG. 5 is a block diagram of a medium access layer in an embodiment of the present invention. ■...Node processor, 2...Physical layer, 3.
...Medium access layer, 4...Logical link layer, 5...Channel control unit, 6...Channel,
7... Frame reception unit, 8... Timer control/failure detection unit, 9, 14... Frame transmission control unit, 10... Frame transmission unit, 11... Reception DMA, 12... Upper interface Section 13... Transmission DMA. Figure 7 Yoku f-key 4 1: 1 Precious bottle frame L-mu T: Talk shift 1 mu A: 2 kyu, 5 answer fushi-4 3rd section/''Gρ': Fushi-muna L7 sequence Entering feel Y゛Csz

Claims (1)

[Claims] 1. After sending an information frame and securing a response area for the first set time, a sending node sends a token frame, and when receiving the information frame, sends a response frame addressed to the sending node within the response area. In a token control method in a ring-shaped network of a token passing access method, which is composed of receiving nodes that are controlled as follows, and is capable of receiving information frames addressed to itself through the network, when an information frame to be transmitted is addressed to itself, the information frame is Until the end of response frame transmission in response to frame reception,
A token control method characterized by suppressing transmission of token frames.