JPH05199247A - Response monitor method and network system - Google Patents

Abstract

PURPOSE:To improve the traffic efficiency by eliminating useless frame transmission to a station whose reception buffer is busy. CONSTITUTION:A station 7 on a network uses a frame reception control section 1 and a response monitor section 2 to always monitor a response frame passing through a transmission line 8, and a network state management section 3 stores the state of a reception buffer 6 of other station 7 connecting to the network together with a time when the reception buffer 6 is busy. A frame transmission control section 4 of a station having a request of sending the frame inquires of the network state management section 3 about the state of the reception buffer of the transmission opposite party prior to the transmission of the frame. When the reception buffer of the opposite party is free as the result of inquiry, the frame is immediately sent but sends the frame after lapse of a prescribed time based on a time when the reception buffer is busy, which is stored in the network state management section 3 when the opposite party is busy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a network system in which a plurality of stations are connected in cascade via a transmission line to transmit and receive data by frames, and in particular,
Regarding the response monitoring method.

[0002]

2. Description of the Related Art In such a conventional network system, a station that receives a frame has means for responding to each station that has transmitted the frame, whether the frame is stored in a receive buffer or the receive buffer is busy. There is.

[0003]

In the conventional network system described above, the state of the receiving buffer of the partner station can be known only after transmitting the frame. In this response monitoring method, for example, even if a station concentrates on one specific station and the receive buffer becomes busy, a frame is transmitted, and if the response to the frame is not received, the receive buffer is busy. However, there is a drawback that the traffic efficiency is lowered because the frame cannot be known and unnecessary frames are flowed on the network.

An object of the present invention is to provide a response monitoring method and a network system capable of improving traffic efficiency by eliminating useless frame transfer to a station whose reception buffer is busy by eliminating the above-mentioned drawbacks. It is in.

[0005]

A response monitoring method of the present invention includes a response frame indicating that a plurality of stations are cascaded via a transmission line and a reception buffer is free or busy. In a response monitoring method in a network system that communicates with each other, each station monitors all the response frames passing on the network, and a status indicating whether the reception buffer of each station is free or busy, and if it is busy When the response information including the busy time is updated and held and the frame is transmitted to the partner station, the frame is immediately transmitted if the reception buffer of the partner station is free based on the held response information. However, if it is busy, the And transmitting the beam.

The network system of the present invention comprises a plurality of stations, each of which is connected in series via a transmission line, and which includes a frame transmitting / receiving means including a response frame indicating whether the receiving buffer is free or busy. In the network system, the station transmits response frames, response monitoring means for monitoring all the response frames passing on the network, network state management means for updating and holding the monitoring result of the response monitoring means as response information, and the frame. In this case, based on the response information, the state of the receiving buffer of the partner station is confirmed in advance. When the receiving buffer is free, the frame is immediately transmitted, and when busy, the frame is transmitted after a certain period of time. control Characterized in that it comprises a stage.

Further, the network system of the present invention is
The network management means is preferably configured to include, as the response information, a station address, a status indicating whether the reception buffer is free or busy, and a time when the reception buffer is busy.

[0008]

[Operation] Each station constantly updates and holds the response information indicating the state of the receiving buffer of each station, and when transmitting a frame, the state of the receiving buffer of the partner station is confirmed based on the held response information. When the reception buffer is free, the frame is immediately transmitted, and when it is busy, the frame is transmitted at a time obtained by adding a predetermined time to the time indicated by the response information.

Therefore, since the frame can be effectively transmitted, useless traffic can be suppressed and the traffic efficiency can be improved.

In the network system using the response monitoring method of the present invention, the response monitoring means for each station to monitor all response frames, the network status management means for updating and holding the response information, and the frame based on the response information. It is realized by including a frame transmission control means for controlling the transmission of the.

The response information includes a station address, a status indicating the state of the reception buffer, and the time when the response frame whose status is busy passes.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a station of an embodiment in the network system of the present invention.

The station 7 of this embodiment has a frame reception control unit 1 for judging whether the frame on the transmission path 8 is a data frame or a response frame, and a response monitor for monitoring only the response frame from the frame reception control unit 1. Part 2
The status of the reception buffer 6 for storing the received frame, the reception buffer control unit 5 for controlling the reception buffer 6, and the reception buffer 6 of the station 7 connected to the network based on the information from the response monitoring unit 2. And a reception buffer control unit 5 for transmitting a data frame and a response frame.
And a frame transmission control unit 4 which refers to the contents of the network status management unit 3.

FIG. 2 shows an example of the configuration of the network state management unit 3, which identifies the station address 31 of a station connected to the same network and whether the state of the receiving buffer 6 of the station 7 having that address is busy or free. If the reception buffer 6 is busy, the status 32 and a time 33 field for recording the time when the response buffer is busy, that is, the time when the response frame whose status is busy, are recorded.

FIG. 3 is a block diagram showing a network system of an embodiment, in which stations (A) 7a to (H) 7h are connected to a transmission line 8.

The feature of the present invention resides in that in FIG. 1, the station 7 has a response monitoring unit 2 as a response monitoring unit for monitoring all response frames passing through the network, and a monitoring result by the response monitoring unit 2. As a network status management means for updating and holding as response information, a network status management unit 3 of which an example is shown in FIG. 2, and when transmitting a frame, the status of the receiving buffer of the partner station is confirmed in advance based on the response information and reception thereof. A frame transmission control unit 4 as a frame transmission control unit including a unit for transmitting a frame immediately when the buffer is free, and a unit for transmitting the frame after a predetermined time when the buffer is busy.

Next, the operation of this embodiment will be described with reference to the flow chart shown in FIG.

In FIG. 3, when data is transferred from the station (A) 7a to the station (B) 7b, the frame transmission controller 4 of the station (A) 7a sends the data frame to the station (B) 7b on the transmission line 8. (Step S1). The station (B) 7b monitors the frame flowing on the transmission path 8 (step S2),
If it is not addressed to its own station, it is relayed and transferred to the next station (step S3),
If the frame is addressed to its own station, it is stored in the reception buffer 6 through the frame reception control unit 1.

For a frame normally stored in the reception buffer 6, a response frame (hereinafter referred to as an RR frame) indicating that the frame transmission control unit 4 has been stored in the reception buffer is instructed by the reception buffer control unit 5. Is sent to all stations connected to the network (steps S4 and S5). Also, if the receive buffer runs out due to increased traffic, etc.,
Similarly to the RR frame, the reception buffer control unit 5 of the station (B) 7b transmits a response frame (hereinafter referred to as a busy frame) indicating that the buffer is exhausted and the frame cannot be received through the frame transmission control unit 4 on the network. Send to all stations (step S)
4, S6).

Each of the stations (A) 7a to (H) 7h monitors the busy frame and the RR frame flowing through the transmission line 8 through the response monitor unit 2, and the address of the station that transmitted the response frame, the content of the response frame, And the response information indicating the time when the response frame has passed is reported to the network status management unit 3 (step S7). The network status management unit 3 stores the statuses of the station reception buffers other than its own station, and updates the status 32 and time 33 of each station (A) 7a to (H) 7h according to the response information from the response monitoring unit 2. (Step S8).

In a station that has a request to transmit a frame, the frame transmission control unit 4 inquires of the network state management unit 3 about the state of the reception buffer 6 of the station of the communication partner (step S9). If the reception buffer 6 is free, , Is immediately transmitted (step S10). If the reception buffer 6 of the partner station is busy, the frame transmission control unit 4 inhibits frame transmission and refers to the time 33 of the network state management unit 3 to see that a certain time has elapsed from the time 33 when the busy was reported. After that, the frame is transmitted (step S11).

[0023]

As described above, according to the present invention, by monitoring all response frames flowing on the network, each station monitors the state of the reception buffer of the station on the network and transmits the frame. The state of the receiving buffer of the partner station can be known in advance. As a result, it is possible to confirm the busy state of the partner buffer before transmitting the data frame, and in this case, there is an excellent effect that the useless traffic on the transmission path is suppressed by suppressing the frame transmission and the traffic efficiency is improved.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing a station in an embodiment of a network system of the present invention.

FIG. 2 is an explanatory diagram showing a configuration example of the network status management unit.

FIG. 3 is a block configuration diagram showing a main part of an embodiment of a network system of the present invention.

FIG. 4 is a flowchart showing the operation.

[Explanation of symbols]

 1 frame reception control unit 2 response monitoring unit 3 network status management unit 4 frame transmission control unit 5 reception buffer control unit 6 reception buffer 7 station 8 transmission line 31 station address 32 status 33 time S1 to S11 step

Claims (3)

[Claims] 1. A response monitoring method in a network system, wherein a plurality of stations are connected in cascade via a transmission line, and a response frame indicating whether a receiving buffer is free or busy is included, and the communication is performed by the frame. Each station monitors all said response frames passing on the network and for each station a status indicating whether its receive buffer is free or busy,
In the case of busy, the response information including the busy time is updated and held, and when a frame is transmitted to the partner station, if the reception buffer of the partner station is free based on the held response information, immediately A response monitoring method characterized by transmitting a frame and, if it is busy, transmitting the frame after a certain period of time. 2. A cascade connection is provided through each transmission line,
In a network system comprising a plurality of stations including means for transmitting and receiving a frame containing a response frame indicating whether the receiving buffer is free or busy, the station monitors all the response frames passing through the network. Response monitoring means, a network status management means for updating and holding the monitoring result by this response monitoring means as response information, and when transmitting a frame, based on the response information, the status of the receiving buffer of the partner station is confirmed in advance, A network system comprising: a frame transmission control means including means for transmitting a frame immediately when the reception buffer is free and transmitting the frame after a predetermined time when the reception buffer is busy. 3. The network management means is configured to include, as the response information, a station address, a status indicating whether the reception buffer is free or busy, and a time when the reception buffer is busy. A network system.