JPH04287455A - Regular reply mode physical level half-duplex communication control system - Google Patents

Abstract

PURPOSE:To convert NRM link level half-duplex communication into NRM physical level half-duplex communication with simple constitution. CONSTITUTION:A physical level control section 13 monitors a P-bit of a frame inputted from a link level half-duplex control section 12c in the physical level half-duplex communication mode, sets an RS line in the case of P=0, and an I frame inputted from the link level half-duplex control section 12c is sent to an NRM terminal equipment via a MODEM 14 to keep the set of the RS line even after the transmission. When a frame of P=1 is inputted from the link level half-duplex control section 12c on the occurrence of a polling, the physical level control section 13 sends the frame to the NRM terminal equipment via the MODEM 14, resets the RS line and gives a token to the NRM terminal equipment and receives the frame from the terminal equipment and inputs it to the link level half-duplex control section 12c.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to NRM (Normal
Response Mode: Normal response mode) Related to the physical level half-duplex communication control method, especially NRM physical level half-duplex communication that converts the link level half-duplex communication method in the NRM procedure to the physical level half-duplex communication method. Regarding control method. NRM is one of the operating modes in the HDLC control procedure, and is the mode of operation of the secondary station in communication between the primary station that controls the data link and the secondary station that performs the data link control function according to instructions from the primary station. This is an operational mode in which the secondary station can send a response only when authorized by the primary station.

[0002]Currently, there are terminals that perform NRM physical level half-duplex communication in addition to NRM link-level half-duplex communication.
There is a need for electronic exchanges that can connect to these terminals. In particular, a switch that can easily convert an NRM link level half-duplex communication system to an NRM physical level half-duplex communication system is desired.

0003

[Prior Art] In the conventional physical level half-duplex control system, before instructing the physical level to transmit a frame at the link level, the physical level is instructed to turn on the RS line. - RS after frame transmission by ring
It tells the physical level to turn off the line.

FIG. 4 is an explanatory diagram of a conventional NRM physical level half-duplex communication procedure, in which 1 is a packet level control section in an electronic exchange, 2 is a link level control section, 3 is a physical level control section, and 4 is a NRM NRM that performs physical level half-duplex communication
This is the modem on the terminal side.

[0005] NRM that performs physical level half-duplex communication
Transmission of a frame to a terminal is performed in the following procedure. That is, the link level control section 2 is the packet level control section 1.
When a DT packet is received from the modem, it instructs the physical level control unit 3 to turn on the RS line, and the physical level control unit 3 instructs the modem 4 to turn on the RS line.When the CS line on is returned from the modem, the link level control unit 3 Notify unit 2 that the CS line has been turned on. As a result, the link level control unit 2 sets the P bit to "
0'' information frame (I frame, P=0) is sent to the physical level control unit 3, and the physical level control unit 3 sends the I frame (P=0) to the modem 4. , I frame
The link level controller 2 sends an RR packet indicating receivability to the packet level controller 1 (see step S1 above).

In such a state, when a polling signal from an NRM terminal is generated within the link level control unit 2, the polling signal is
Triggered by the ring signal, the link level control unit 2 transmits the RR frame with the P bit set to “1” to the physical level control unit 3.
The physical level control section 3 transmits the RR frame to the modem 4, and returns the completion of RR frame transmission to the link level control section 2. As a result, the link level control section 2 instructs the physical level control section 3 to turn off the RS line, the physical level control section 3 instructs the modem 4 to turn off the RS line, and when the modem returns CS line off, the link Level control section 2
Notify the CS line off completion. As described above, the NRM terminal that performs NRM physical level half-duplex communication acquires the transmission right and becomes ready to transmit an I frame (see step S2 above).

Thereafter, after turning on the CD line, each time an I frame with the F bit of "0" is sent from the NRM terminal via the modem 4, the physical level control unit 3 is input to the link level control unit 2, and the link level control unit 2
is converted into a DT packet and sent to the packet level control section 1. The NRM terminal sets the F bit of the last I frame to "1" and sends it, and also turns off the CD line, thereby passing the transmission right to the exchange (see step S3 above). still,
DT packets generated from the packet level control unit 1 between steps S2 and S3 are connected to a transmission waiting queue in the link level control unit 2.

[0008] When the I frame with F=1 is received and the transmission right is returned to the exchange, the link level control unit 2 determines whether the DT packet is connected to the transmission waiting queue or from the packet level control unit 1. If a DT packet is received, the processing from step S1 onwards is repeated.

[0009]

Problems to be Solved by the Invention At the link level, processing is required for the occurrence of many events such as reception of various frames. Therefore, if the link level half-duplex communication control and the physical level half-duplex communication control are to be performed in parallel at the link level, the scale of development will be large.

From the foregoing, it is an object of the present invention to provide a communication control method that enables both NRM link level half-duplex communication and NRM physical level half-duplex communication in an electronic exchange with a simple configuration.

[0011]

[Means for Solving the Problems] FIG. 1 is a diagram illustrating the principle of the present invention. 10 is an electronic exchange, 11 is a packet level control section in the electronic exchange, 12 is a link level control section, 12
Reference numeral c indicates a link level half-duplex control unit, 13 indicates a physical level control unit, and 14 indicates a modem on the NRM terminal side that performs NRM physical level half-duplex communication.

0012

[Operation] In the physical level half duplex communication mode, the physical level control unit 13 monitors the P bit of the frame input from the link level half duplex control unit 12c, and
1", "0", performs on/off control of the RS line, converts NRM link level half-duplex communication to NRM physical level half-duplex communication, and transmits an I frame to the NRM terminal,
and receives an I frame from the NRM terminal.

That is, the physical level control section 13 controls P=
When it is 0, the RS line is turned on and the I frame input from the link level half-duplex control unit 12c is transmitted to the modem 14, and the RS line is kept on even after transmission. After that, the port
When an I frame with P=1 is input from the link level half-duplex control unit 12 using the ring as a trigger, the physical level control unit 13 transmits the I frame to the modem side and turns off the RS line. The transmission right is granted to the NRM terminal, and an I frame is received from the terminal and input to the link level half-duplex control unit 12c.

As described above, in the physical level half-duplex communication mode, the physical level control section controls the P of the input frame.
It monitors the bit and automatically controls on/off of the RS line based on "1" and "0" of the P bit, converting NRM link level half-duplex communication to NRM physical level half-duplex communication. Since I-frames are sent to and received from NRM terminals, NRM link-level half-duplex communication can be converted to NRM physical-level half-duplex communication with a simple configuration. .

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Overall Configuration FIG. 2 is a diagram showing the configuration of a network according to the present invention, and the same parts as in FIG. 1 are given the same reference numerals. 10 is an electronic exchange, 11 is a packet level control unit (level 3) in the electronic exchange, 12 is a link level control unit (level 2), 1
3 is a physical level control section (level 3). The link level control unit 12 includes an ABM full duplex link level control unit 1.
2a, NRM full-duplex link level control unit 12b, NRM
A link level half-duplex control section 12c is provided, and the physical level control section 13 is provided with a storage section 13a, an information transmission/reception control section (not shown), and a signal line control section. The storage unit 13a stores correspondence between lines #0 to #n and communication modes (physical level full-duplex communication, physical level half-duplex communication). Note that "full duplex designation" and "half duplex designation" written between the link level control unit 12 and physical level control unit 13 in FIG. This indicates double, and this is stored in the storage unit 13a. The physical level communication mode (full duplex, half duplex) stored corresponding to lines #0 to #n is referred to by the physical level control unit 13, and the physical level communication mode (full duplex, half duplex) stored corresponding to lines #0 to #n is referred to by the physical level control unit 13, and the physical level communication mode (full duplex, half duplex) is Used to determine whether or not to communicate. Note that even when the link level is half-duplex, the physical level may be full-duplex, and this is a link-level half-duplex communication system.

14 and 15 are modems provided at both ends of the telephone network; 16 is a telephone network; 17 is a packet switching network; 21 is a packet type terminal; and 22 is an NRM terminal that performs NRM physical level half-duplex communication. The NRM terminal 22 determines that P bit=
After receiving the frame 1, it obtains the right to transmit and turns on the RS line.
A frame with the F bit = 0 is transmitted, the F bit of the final frame is set to 1, and the transmission right is returned to the exchange. In half-duplex communication at the physical level, the RS line is turned on, and frames can be transmitted when the CS line is turned on from the other party.

[0017] Note that #0 and #1 are X25 lines (ABM full duplex lines), #2 is NRM link level full duplex/NRM physical level full duplex terminal line, and #3 is NRM link level half duplex/NRM physical level full duplex terminal line. NRM physical level full-duplex terminal line, . . . #n is an NRM link level half-duplex/NRM physical level half-duplex terminal line.

NRM physical level half-duplex communication procedure Figure 3 shows NRM physical level half-duplex communication procedure.
FIG. 2 is an explanatory diagram of a RM physical level half-duplex communication procedure, and the same parts as in FIG. 2 are given the same reference numerals. It is assumed that data is exchanged between the packet type terminal 21 (FIG. 2) and the NRM terminal 22, and the electronic exchange 10 and the packet type terminal 21
It is assumed that the links between the packet terminal 21 and the electronic exchange 10 and the NRM terminal 22 have already been established, and that a logical channel at the packet level between the packet terminal 21 and the electronic exchange 10 has also been formed. Furthermore, since the correspondence between lines and communication modes is set in the storage unit 13a of the physical level control unit 13, communication on the line on the NRM terminal 22 side is determined based on the correspondence when setting the link between the terminals 21 and 22. The mode is known to be a physical level half-duplex communication mode.

Data transmitted from the packet form terminal 21 is input to the electronic exchange 10, and is sent to the physical level control section 13.
, is input to the packet level control unit 11 via the ABM full-duplex link level control unit 12a, and thereafter transmits the frame to the NRM terminal 22 and performs NR processing according to the procedure shown in FIG.
Frame reception from M terminal 22 is performed.

The packet level control section 11 creates a DT packet based on the data from the packet form terminal 21, and inputs it to the link level half-duplex control section 12c. The link level half-duplex control unit 12c is the packet level control unit 11.
When receiving a DT packet from the physical level controller 13, it sends a transmission request (I frame, P=0) to the physical level controller 13. The physical level control unit 13 connects the transmission request to the transmission waiting queue, checks the value of the P bit, and since P=0, sends an RS line ON signal to the modem 14. When the modem returns CS line ON, the I frame (P=0) connected to the transmission waiting queue is sent to the NRM terminal 22 via the modem 14.
At the same time, the link level half-duplex control unit 12c is notified of the completion of I frame transmission. Note that the RS line is left on without being turned off.

Upon receiving the completion of I frame transmission, the link level half-duplex control section 12c sends an RR packet indicating receivability to the packet level control section 11 (see step S1 above).

In this state, when a polling signal from the NRM terminal is generated within the link level half-duplex control unit 12c, the link level half-duplex control unit 12c sets the P bit to “1” using the polling signal as a trigger. ” is sent to the physical level control unit 13, and the physical level control unit 13
transmits the RR frame (P=1) to the NR frame via the modem 14.
It transmits to the M terminal 22 and also returns the completion of RR frame transmission to the link level half-duplex control unit 12c.

After that, the physical level control unit 13 sends an RS line off signal to the modem 14, and when a CS line off signal is returned from the modem 14, the NRM terminal 22 acquires the transmission right and transmits an I frame. becomes possible (step S2
reference). Incidentally, during step S2, the DT packet sent from the packet level control section 11 to the link level half-duplex control section 12c is connected to the transmission waiting queue.

After that, after turning on the CD line, the NRM terminal 2
2 through the modem 14 with the F bit set to 0.
Each time a frame is sent, the physical level control section 13 inputs the I frame (F=0) to the link level half duplex control section 12c, and the link level half duplex control section 12c converts it into a DT packet. It is sent to the packet level control section 11. And N.R.
The M terminal 22 sets the F bit of the last I frame to "1" and sends it, and also turns off the CD line, which causes the NRM terminal 22
transfers the transmission right to the electronic exchange 10 (step S3
).

When an I frame with F=1 is received and the transmission right is returned to the exchange, the link level half-duplex control unit 12c issues a transmission request (if a DT packet is connected to the transmission waiting queue). The I frame (P=0) is sent to the physical level control unit 13, and thereafter the same transmission procedure as steps S1 to S3 is performed. Although the present invention has been described above with reference to examples, the present invention can be modified in various ways according to the gist of the present invention as described in the claims, and the present invention does not exclude these modifications.

[0026]

As described above, according to the present invention, in the physical level half-duplex communication mode, the physical level control section monitors the P bit of the input frame and determines whether the P bit is "1" or "1". 0
Automatically performs on/off control of the RS line based on the
Since the NRM link level half-duplex communication is converted to NRM physical level half-duplex communication and the configuration is configured to transmit I frames to the NRM terminal and receive I frames from the NRM terminal, it is easy to use. The configuration can convert NRM link level half-duplex communication to NRM physical level half-duplex communication.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is an explanatory diagram of the NRM physical level half-duplex communication procedure of the present invention.

FIG. 4 is an explanatory diagram of a conventional NRM physical level half-duplex communication procedure.

[Explanation of symbols]

10...Electronic switchboard 11...Packet level control section 12...Link level control section 12c...Link level half-duplex control unit 13...Physical level control section 14...modem

Claims (2)

[Claims] Claim 1. In a regular response mode physical level half-duplex communication control system for an electronic exchange equipped with a physical level control unit, a link level control unit, and a packet level control unit, the physical level control unit is a physical level half-duplex communication mode. - In the code,
The link level control unit monitors the P bit of the frame input from the half-duplex link level control unit, and
NRM physical level half-duplex communication is characterized in that it performs on/off control of the RS line based on 1" and "0" and converts normal response mode link level half-duplex communication to normal response mode physical level half-duplex communication. Duplex communication control method. [Claim 2] When P=0, the RS line is turned on and the frame input from the link level half-duplex control unit is transmitted to the normal response mode terminal on the modem side, and the RS line is kept on after transmission. Then, when a frame with P=1 is input from the link level half-duplex control section, the frame is transmitted to the modem side and the RS line is turned off, and then the normal response mode is set. 2. The normal response mode physical level half-duplex communication control system according to claim 1, wherein a frame from a terminal is received and inputted to a link level half-duplex control section.