JPH04261244A - Lan multiplexer - Google Patents

Abstract

PURPOSE:To relieve the load relating to input/output processing delivered to a host CPU. CONSTITUTION:The LAN multiplexer is provided with two LAN connection sections 1a, 1b, a central processing unit 4 and a main storage section 5 and combines plural messages sent from each terminal equipment 6 to a host computer 7 to generate a message with a maximum length allowed to the frame length and sends the result to the host computer 7.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention combines messages from multiple terminal side LANs in a data ring layer and transmits them to a host computer (hereinafter referred to as host) side bus type LAN local area network (hereinafter referred to as LAN). Regarding the multiplexer that does.

0002

[Prior Art] Conventionally, in a network system in which a host side receives a large amount of short messages from multiple terminals, the host performs message reception waiting processing for all terminals, and then performs reception processing for each individual message. was.

0003

[Problems to be Solved by the Invention] In the conventional method described above, the host individually processes messages from each terminal. There is a problem in that the load related to output processing increases in proportion to the number of I/Os of the control unit.

[0004] Furthermore, since the host must process reception requests for all terminals, it is necessary for the host to recognize the station address of each terminal and the number of terminals, and if the number of terminals changes, the host The problem is that the software must also be modified.

An object of the present invention is to provide a LAN multiplexer that reduces the input/output processing load placed on a host CPU and eliminates the need to modify host software.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the LAN multiplexer according to the present invention connects one host computer and a plurality of terminals to a bus-type L
In a network system connected by an AN local area network and in which a host computer receives a large amount of short messages from a terminal, there is a LAN connection section for connecting to the host computer side bus type LAN local area network, and a terminal side bus type LAN. A LAN connection unit for connecting to a local area network, a central processing unit for combining received messages, a main storage unit for storing the station address of each terminal and a plurality of messages that have not been transferred after being received; It has a timer management section that manages a timer activated to continue waiting for message reception from a terminal for a certain period of time, and combines and relays messages from a host computer from multiple terminals at the data ring layer.

[0007] Also, a plurality of messages sent from each terminal to the host computer are combined to create a message with the maximum length allowed by the frame length, and this message is sent to the host computer.

[0008] Furthermore, even if the message length of the message to be transmitted is less than the frame length due to expiration of the reception wait timer, it serves to prompt the host computer to transmit the message.

[0009]

[Operation] The LAN multiplexer of the present invention combines multiple messages sent from each terminal to the host, creates a message with the maximum length allowed by the frame length, and sends this to the host. be.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of the present invention. In the figure, this embodiment has two LAN connections 1a and 1b.
, central processing unit 4, main storage unit 5, and timer management unit 4
It has a. 6 is a terminal, and 7 is a host computer.

[0011] Each LAN connection section 1a, 1b is connected to the host side L.
It is connected one-to-one to the AN or terminal-side LAN, and inputs and outputs messages.

The central processing unit 4 combines messages sent from the terminal 6 to the host 7 and determines addresses.

The main storage section 5 stores the station address of the terminal 6 and unsent messages received from the terminal 6.

[0014] The timer management section 4a controls the host 7 for a certain period of time.
It accepts activation of a timer for waiting for a message to be sent to the terminal 6 or for continuing to wait for a message to be received from the terminal 6, and notifies the expiration of the timer.

Next, the flow of processing will be explained in two cases with reference to FIGS. 2 and 3.

(1) When receiving a message from a terminal (Figure 2
reference)

[0017] When the message received from the terminal is the first message reception (Fig. 2 [2-1]), a timer (hereinafter referred to as reception wait timer) is used to continue waiting for reception of the message from the terminal 6 for a certain period of time thereafter. (same [2
-2]).

Next, check the message length of the received message (hereinafter referred to as received message) and the message length of the message being edited to be sent to host 7 (hereinafter referred to as sending message) (same [2-3]). Append the received message to the outgoing message, up to the maximum length (
Same [2-7]).

If the message length exceeds the frame length (same [2-3]), send only the outgoing message to the host 7 (same [2-5]), and then send the outgoing message once. Clear and set the received message (same [2-4]). At the same time, the reception wait timer is temporarily stopped and then restarted (ibid. [2-4]).

(2) When the reception wait timer expires (see Figure 3)

Even when the amount of messages transmitted from each terminal decreases, the present multiplexer waits for message transmission until the length of the message transmitted to the host reaches the frame length. To avoid this, even if the length of the message to be sent is less than the frame length due to the expiration of the reception waiting timer,
It has the role of prompting the process of sending messages to the host.

[0022] If there is a message in the sending message area when the reception waiting timer expires (Fig. 3 [3-1]),
This is sent to the host (same [3-2]) and the same area is cleared (same [3-3]). When the reception wait timer expires,
There is no need to start the same timer again.

[0023]

Effects of the Invention As explained above, in a local area network system in which a host receives a large amount of short messages from multiple terminals, the present invention combines multiple messages from the terminals to reduce the maximum length allowed by the frame length. Since a long message is created and sent to the host, the number of I/O operations on the host can be reduced, and the load on the host CPU regarding input/output processing can be reduced. Another advantage is that the host does not need to be aware of each terminal station address or the configuration of the terminals, and even if the number of terminals changes, there is no need to modify the host software.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing the flow of processing when receiving a message from a terminal.

FIG. 3 is a diagram showing the flow of processing when a reception wait timer expires.

[Explanation of symbols]

1a, 1b LAN connection part 4 Central processing unit 5 Main memory section 6 Terminal 7. Host computer

Claims (3)

[Claims] Claim 1: In a network system in which one host computer and a plurality of terminals are connected via a bus-type LAN local area network, and the host computer receives a large amount of short messages from the terminals, the host computer side A LAN connection unit for connecting to a bus type LAN local area network, a LAN connection unit for connecting to the terminal side bus type LAN local area network, a central processing unit for combining received messages, and a station address for each terminal. It has a main storage unit for storing a plurality of messages that have not been forwarded after being received, and a timer management unit that manages a timer that is activated to continue waiting for message reception from a terminal for a certain period of time. A LAN multiplexer that combines and relays messages from terminals to a host computer at a data ring layer. [Claim 2] A method that combines multiple messages sent from each terminal to the host computer to create a message with the maximum length allowed by the frame length, and sends this to the host computer. A LAN multiplexer as claimed in claim 1. [Claim 3] A claim characterized in that the expiration of the reception wait timer serves to prompt the host computer to send the message even if the message length of the message to be sent is less than the frame length. 1. The LAN multiplexer according to 1.