JPS6017190B2 - Method for coupling multidrop lines to store-and-forward networks - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scheme for coupling multidrop lines to a store-and-forward network.

Conventionally, in a multidrop line, as shown in FIG. 1, a computer 2 and a group of controlled terminals 3 to 6 are connected to a specific communication line 1, and the computer 2, which is the main control terminal, connects each controlled terminal 3 to 6. 6 is sequentially bowled or selected, and communication is performed.

An example of the sequence in this case is shown in FIG. In Figure 2, ENQ1(P) is the boring address and terminal 1
A signal requesting a response as to whether there is data to be sent to 01, EO
T is a negative response to bowling and is a signal when there is no data to be transmitted, DATA2 is data transmitted from the terminal 102,
ACK is a signal indicating that data has been received correctly, EN
Q3(S) is a selecting address and is a signal requesting a response from the terminal 103 as to whether or not it is ready for reception;
CK is a positive response signal to selection.

If such a multi-drop line is accommodated in a store-and-forward network (hereinafter referred to as a packet network), the configuration will be as shown in FIG. 3, and the sequence will be as shown in FIG. 4.

In FIG. 4, messages between interfaces INTF in the packet network (NW) 11 are preceded by a packet header PH, followed by text. The packet header PH is used for text route instructions and the like.
In FIG. 3, a plurality of terminals may be connected in duplicate to save subscriber lines.

However, as is clear from the sequence example shown in FIG. 4, a large number of daily and reverse monitoring sequence packets that do not contain data pass through the packet network 11, resulting in an extremely large load. .

Controlled terminal groups 13, 14, 15 seen from the main control terminal 12
The response from the network may exceed the predetermined timing due to the delay To within the packet network.

In this case, the main control terminal 12 assumes that the boring data has not reached the controlled terminal group 13 to 15, and sends out the boring data again, which increases the load and increases the throughput of the subscriber system.・Put decreases. Furthermore, since the number of packet network transmissions increases for subscribers, the burden of charges becomes large. The purpose of the present invention is to eliminate the above-mentioned drawbacks by controlling the interface with the packet network to reduce the number of packets other than data passing through the packet network, thereby shortening the delay within the network. At the same time, the objective is to suppress the decline in throughput of the subscriber system.

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

Figure 5 is an example of multi-drop line accommodation in a packet switching network, Figure 6 is a connection example showing the logical combination method in Figure 5, and Figure 7 is a sequence example when the basic procedure is used in Figure 5. It is.

In FIG. 5, controlled terminal groups 53 to 58 are connected to three packet switching stations 59, 60,
It is divided into 61 parts and accommodated. Each packet switching station 59
, 60, 61 are controlled terminal groups 63-55, 56-57,
58 respectively. On the other hand, the main control terminal (computer C
The PU) 52 controls these terminal groups 53 to 58, and logically connects n controlled terminals 101 to 1 on one specific communication line, as shown in FIG. It looks like.

As shown in FIG. 7, the computer 52 is connected to the packet switching center 62
As shown in FIG. 6, the controlled terminals 101 to Ion are controlled as if they were connected on a multi-drop line.

On the other hand, the controlled terminal accommodating stations 59, 60, and 61 each successively bore the terminal group. If the terminal 102 receives a transmission request for the boring signal 100' from the packet exchange station 59, the terminal 102 transmits the data 101 to the packet exchange station 59.

The packet station 59 returns an acknowledgment signal 102 to the terminal 102, confirming that the data 101 has been received normally, and at the same time sends the received data to the packet station 62 along with terminal information (indicating that the data was sent by the terminal 102). information), packetized 301 and transmitted to the packet station 62. Packet station 6 that received this packet 301
2, the boring signal from the computer 52 is sent to the terminal 102.
This data will be accumulated and retained until

The packet station 59 continues to communicate with the terminal 102 until it receives the communication end signal 103 from the terminal 102. Next, packet station 59 transmits boring signal 104 to terminal 103. The bucket station 62 holds the data 101, receives the boring signal 200 from the computer 52, identifies it as being for the terminal 102, and transmits the held data 101 as data.

In response, the computer 52 returns a signal 202 indicating that it has been successfully received. If the packet station 62 has no data to send to the computer 52, it sends a communication end signal 203.
Send. When the computer 52 receives this end signal 203, it bowls the next terminal 103. Like the packet station 59, the bucket stations 60 and 61 also perform boring, and the data from the terminal 104 that has been bored by the packet station 60 is transmitted to the packet station 62 in a packet 302.

As in the case of the bucket station 301, the packet station 62 stores and holds the data until a boring signal is received from the computer 52 to the terminal 104. When the computer 52 transmits data to the terminal 101, the computer 52 transmits a selecting signal 204 to the packet station 62.

The packet station 62 checks the status of the corresponding terminal 101 and returns an affirmative signal 205 if it is in a communicable status. Thereby, the computer 52 transmits the data 206 to the packet station 62. The packet station 62 transmits a confirmation signal 207 indicating that the data 206 has been received normally to the computer 52, adds terminal information (information indicating that the data is sent to the terminal 101) to the data, and packetizes the data. 303 and transmits it to the packet station 59. The packet station 59 that receives this packet 303 stores and holds this data until it is the time for selection to the terminal 101.

The packet station 62 continues to communicate with the computer 52 until it receives a communication end signal 208 from the computer 52.

Packet station 62 then receives the next bowling or selecting signal from computer 52. Packet station 5
9 holds data 206, but packet station 5
When it is the turn of terminal 9 to select terminal 101, selecting signal 105 is transmitted.

If the terminal 101 is in a receivable state, the terminal 101 sends an acknowledgment signal 1.
06 is returned, and when the packet station 59 receives this, it transmits the data 206 as the data 107. Terminal 101
returns a normal reception response 108 in response to this data 107, and the packet station 59 receives the response signal 108 and, if there is no data to be transmitted, transmits a communication end signal 109 and performs boring or selection to the next terminal 102. Start. Since the packet stations 59 and 62 perform boring independently, buffer capacity shortages occur in each of them, and control for adjustment between the packet stations is required.

These control information are sequentially exchanged between the packet stations PS, and each packet station PS controls the flow by stopping boring, indicating terminal busy for selecting, etc. As explained above, the present invention According to the method, each terminal accommodating station in a store-and-forward network independently performs boring or selecting operations, transfers received data between each terminal-accommodating station via the store-and-forward network, stores and holds the data, and communicates the received data with each terminal through the store-and-forward network. Since data is transmitted to a desired terminal in synchronization with boring or selecting control between terminal accommodation stations, the amount of data passing through the store-and-forward network is minimized, and
Decrease in system throughput due to accommodating multi-drop lines in the store-and-forward network is also suppressed, and the economic burden on subscribers is reduced.

In this embodiment, the basic procedure is adopted as the transmission control procedure, but it is also possible to use other transmission control procedures such as the high level procedure (HDLC procedure).

Furthermore, although the computer is used as the main control terminal, it is also possible for the packet switching station (PS62) to perform boring or selecting using the computer as the controlled terminal. moreover,
The terminal is not a packet exchange center, but a PAD (Packet
It can also be applied when connecting to a ship (deassembly).

[Brief explanation of the drawing]

Figure 1 is a connection diagram of a multi-drop line using a specific communication line, Figure 2 is a sequence chart when the basic procedure is used in Figure 1, and Figure 3 is a connection diagram of a multi-drop line using a specific communication line. Connection diagram when accommodated, No. 4
3 is a sequence chart in FIG. 3, FIG. 5 is a connection diagram of a multi-drop line to a packet switching network showing an embodiment of the present invention, and FIG. 6 is a connection diagram showing a logical connection method in FIG. 5. FIG. 7 is a sequence chart when the basic procedure is used in FIG. 1: Multidrop line, 2, 12, 52: Computer (main control terminal), 3-6, 13-15, 53-58: Controlled terminal, 51: Packet switching network, 59-62: Packet switching center, P /S: Bowling or selecting signal,
INTF: Interfacial Engineering. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. In a system in which one polling or selecting main control terminal and one or more polling or selecting controlled terminals are coupled via a store-and-forward network, the main control terminal and the means for independently polling or selecting between the terminal accommodating exchanges; means for polling or selecting each of the controlled terminals independently from the terminal accommodating station; and means for transmitting data between the terminal accommodating stations. 1. A method for coupling a multi-drop line to a store-and-forward network, characterized in that, after transmitting control information, a means is provided for temporarily storing and holding the received terminal information in the receiving terminal accommodation station. 2 After the polling operation, the controlled terminal accommodating switching center
The data received from the controlled terminal is transferred to the main control terminal accommodating station via a store-and-forward network, and the data is transferred to the main control terminal in synchronization with polling control between the main control terminal and the terminal accommodating station. A system for coupling a multi-drop line to a store-and-forward network according to claim 1. 3 After the selecting operation, the main control terminal accommodating station transfers the data received from the main control terminal to a predetermined controlled terminal accommodating station via the store-and-forwarding network, and performs the selecting operation of the controlled terminal accommodating station. 2. A system for coupling a multi-drop line to a store-and-forward network according to claim 1, wherein the multi-drop line is transferred to a controlled terminal in synchronization with the control terminal.