JPH0247943A - Communication method between local area networks - Google Patents

Abstract

PURPOSE:To suppress abort of information at a repeater by informing a suppression signal to a sender with a flow control means provided to the repeater if the capacity of a buffer is deficient and allowing a caller terminal equipment or the repeater to send the suppression signal while retarding the succeeding information in a predetermined time. CONSTITUTION:Local sub area networks 1, 2, 3 are connected by respective repeaters 13, 23, 33 and a reception suppressing level management state diagram for the suppression signal received from other repeaters is provided to the respective repeaters 13, 23, 33. When the repeater 13 receives a suppression signal from the repeater 20, the type and suppression level of the received repeater 23 are registered in the reception suppressing level management state diagram. Moreover, the repeater 20 sends the succeeding information to be sent while retarding it by a prescribed time Tn and even if number of buffers in use in the repeater 13 is within an operating area 0, the reception suppressing level management state diagram is referenced and when no signal is received from the repeater 23, when the information from a terminal equipment 11 is received, the same suppression signal as the suppression level from the repeater 23 is informed to the terminal equipment 11.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for controlling the flow of information in repeaters and terminals when interconnecting local area networks.

BACKGROUND OF THE INVENTION In the conventional communication method between local area networks via a repeater, a terminal starts a response waiting timer and then sends information to the repeater, and the repeater has a pre-determined timer to receive the information. A buffer is prepared, but if the buffer runs out, the received information is discarded.

The discarded information is retransmitted when the terminal's response waiting timer times out.

Problems that the invention sought to solve However, with the method described above, when the frequency of communication with other local area networks via repeaters increases, there are many cases where the repeaters run out of buffers, resulting in a high rate of information being discarded. It gets expensive. As a result, the discarded information has to be retransmitted, resulting in a problem that communication efficiency is reduced.

Means for Solving the Problems The present invention uses a flow control means provided in a repeater to notify a suppression signal to the source terminal or repeater when the buffer capacity becomes insufficient, and to receive the suppression signal. This communication method between local area networks is characterized in that the terminal or repeater that sent the information is delayed by a predetermined period of time before transmitting the subsequent information.

Function: The present invention sends a suppression signal to the source before the buffer capacity of the repeater runs out and delays the transmission of subsequent information, thereby reducing the frequency of communication with other local area networks via the repeater. Efficient communication is possible even when the number of devices increases.

Embodiment FIG. 1 shows a network configuration in a first embodiment of the present invention. In Figure 1, 1.2.3 is a local subarea network, 11.12, 21.2
2, 31, and 32 are terminals, and 13, 23, and 33 are repeaters. Terminal 1 in local subarea network 1
1 and a terminal 22 in the local subarea network 2 will be described. The information sent from the terminal 11 is transmitted to the relay 1 of the local subarea network 1.
3, and then transmitted to the repeater 23 of the local subarea network 2, and the repeater 23 further transmits it to the terminal 22. At this time, the repeater 13 and the repeater 23 prepare buffers in advance in order to transmit information to other repeaters or terminals. FIG. 2 shows the buffer management method. For example, if the number of buffers used exceeds a percentage of the total, the suppression level is set to 1, and if the number of buffers used exceeds a percentage, the suppression level is set to 2. If it is within the range of area 0, the received information is transmitted to the repeater 23. However, when the usage area reaches 1 or 2, the received information is transmitted to the repeater 23 and, at the same time, the terminal 11 is notified of the suppression signals 1 and 2. Further, when the buffer is all in use in the used area 3, the information is discarded and the suppression signal 3 is notified to the terminal 11.

On the other hand, when the terminal 11 receives the suppression signal, it transmits the information to be transmitted next with a delay of Tn time depending on the level of the suppression signal. Furthermore, the next information is similarly delayed by Tn time and transmitted. This delayed transmission operation is performed N times after receiving the suppression signal.

In other words, the information you want to send from the terminal 11 is A1゜A2
, A3. ..., An, when a signal of suppression level 1 is received by sending out the first information A1, the information A2
The transmission of A is delayed by Tn time, and the subsequent A
3. ..., An information is also transmitted with a delay of Tn time. If the first suppression repeat/L/1 also receives a suppression signal with a high suppression level during N delayed transmissions, from that point on, the delayed transmission is repeated N times with a delay time corresponding to the new suppression level. Implemented twice.

Note that the upper layer in the terminal or repeater may also start a response waiting timer when transmitting information. After receiving the suppression signal, this timer value may be changed to the initial setting value depending on the level of the suppression signal. Change the setting to a larger value for Tn time. Furthermore, when delayed transmission is canceled, the response waiting timer value is returned to the initial setting value.

Although the communication method described above is between a repeater and a terminal, a similar communication method can also be used between repeaters. Let me explain that case. A reception suppression level management state diagram as shown in FIG. 3 is provided in the repeater to manage the level of suppression signals received from other repeaters. When the repeater 13 receives the suppression signal from the repeater 23, it registers the type and suppression level of the received repeater in the reception suppression level management state diagram. Then, the repeater 23 transmits the next information to be transmitted with a delay of Tn time in the same manner as described above. Also, the number of used buffers of the repeater 13 is 0.
Even within the range of
By notifying the terminal 11 of the same suppression signal as the suppression level received from the repeater 23 at the time of receiving the information from the repeater 23, the buffer capacity of the repeater of another local subarea network is insufficient Even if there is a network, the same communication method as above can be used. The above procedure is shown in FIG.

FIG. 5 shows a second embodiment of the invention. In the first embodiment, after receiving the suppression signal, delayed transmission is performed N times and then the delayed transmission is canceled, but in the second embodiment, when the number of used buffers returns to 0, the delayed transmission is canceled. Cancel delayed transmission.

That is, when the buffer flow control means in the repeater transmits the suppression signal to the second terminal or another repeater, the sixth
The type and suppression level of the terminal or repeater at that time is registered in the transmission suppression level management state diagram shown in the figure, and the number of buffers used returns to 0 in the buffer management state diagram shown in Figure 2. At this point, the suppression signal 0 is notified to the related terminals or repeaters with reference to the transmission suppression level management state diagram shown in FIG. The terminal or repeater that receives the suppression signal 0 cancels delayed transmission at that point, returns the upper layer timer value within the terminal or repeater to its original value, and transmits subsequent information in a normal state.

As described above, according to this embodiment, by providing the buffer flow control means in the repeater, it is possible to notify the source terminal or other repeaters of the buffer usage status in the repeater. Furthermore, the terminal or repeater that has received the suppression signal can delay and transmit subsequent information at a suppression level that matches the usage status of the buffer of the repeater.

This reduces the amount of information discarded at the repeater, and can be expected to provide efficient communication.

Note that the suppression level can be set according to the number of buffers that can be prepared by the repeater and the degree of communication of information passing through the repeater.

As described in detail, according to the present invention, when local area networks communicate with each other via a repeater, it is possible to suppress information discard at the repeater as much as possible, and its practical effects are as follows. big.

[Brief explanation of the drawing]

Fig. 1 is a network configuration diagram according to the present invention, Fig. 2 is a buffer management state diagram within a repeater, and Fig. 3 is reception suppression level management for managing suppression signals received from other repeaters in a repeater. State diagram, FIG. 4 is a delayed transmission procedure diagram of the first embodiment, FIG. 6 is a delayed transmission procedure diagram of the second embodiment,
The figure is a transmission suppression level management state diagram for managing a suppression signal when the result of flow control within a repeater is transmitted to a terminal or another repeater in order to implement the second embodiment. 1.2.3... Local subarea network, 11.12.21.22, 31.32...
Terminal, 13, 23, 33... Repeater. Name of agent: Patent attorney Shigetaka Awano and one other person Fig. Fig. Fig. Fig. ↓ Fig.

Claims (2)

[Claims] (1) In a network system in which multiple terminals are connected to a local area network and the local area networks are interconnected by repeaters, each repeater transmits information transmitted from the terminal or other repeaters. It has a storage buffer and a flow control means for controlling the flow of this buffer, and when the capacity of the buffer becomes insufficient, the flow control means notifies the source terminal or repeater of a suppression signal and suppresses the flow. A communication method between local area networks, characterized in that the source terminal or repeater that receives the signal delays subsequent information by a predetermined time and then transmits it. (2) The suppression signal is a multi-level signal depending on the degree of lack of buffer capacity, and the source terminal or repeater
2. The method for communicating between local area networks according to claim 1, further comprising delaying subsequent transmission of information for a predetermined period of time depending on the level of the received suppression signal.