JPH0440727A - Communication controller suited to osi transport protocol class 4 - Google Patents

Abstract

PURPOSE:To shorten the processing time related to a timer which monitors the inactive time and the window time by using a common timer to monitor both times. CONSTITUTION:A control part 2 receives a signal TC for settlement of the connection and starts a timer 1. Then the timer 1 produces a time-out signal 102. At the same time, a counter 3 counts the number M of continuous intervals T when no TPDU is received. When the M exceeds a prescribed level, a comparator 5 outputs an inactive time elapsed signal 105. Then the part 2 releases the connection. Meanwhile a counter 4 counts the number N of continuous time intervals T when no AK TPDU is transmitted by means of the signal 102 received from the timer 1. When the N exceeds a prescribed level, a comparator 6 outputs a window time elapsed signal 108. Then the part 2 transmits the AK TPDU.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides improved communication control equipment that satisfies 05I transport protocol class 4, particularly time monitoring that satisfies OSI transport protocol class 4. It relates to a communication control device.

[Conventional technology]

03I) Transport Protocol Kurasu 4 is a transport protocol for facilitating communication in Open Systems Interconnection (O3I) and includes error detection and recovery functions. JIS X 510 regarding O3IM transport protocol class 4
9, the transport protocol data unit (hereinafter referred to as
When the inactivity time I expires without receiving a TPDU), the transport entity initiates a release procedure;
In addition, to prevent the inactivity monitoring timer of the remote station's transport entity from timing out, the local station's transport entity must transmit an acknowledgment transport protocol data unit (hereinafter abbreviated as AK TPDU) at appropriate time intervals. has been done. In order to guarantee this, the transport entity is required to transmit an AK TPDU at least once within the window time W.

In the conventional 05I) transport protocol class 4 implementation, that is, in the communication control device that complies with the same protocol, in order to monitor the time to satisfy the above, as shown in Fig. 6, the inactivity time I has elapsed after the start. Then, the I timer 61 notifies you of a timeout, and the W timer 6 notifies you of a timeout when the window time W has elapsed after the start.
2, and a control section 63 for controlling start, stop, and restart of the timer 61 and
The steps shown in the figure were executed.

That is, the timer 61 is started by a start signal 601 issued from the control unit 63 when a connection is established (FIG. 7(A)), but if a TPDU is received before the inactivity time has elapsed, the timer 61 is started by a stop signal issued from the control unit 63. 602
The W timer 62 is stopped midway and restarted by the start signal 601 (FIG. 7(B)), and the W timer 62 receives the start signal 60 issued from the control unit 63 when the connection is established.
3 (FIG. 7(A)), but if AK TPDU transmission is performed before the window time W elapses, it is stopped halfway by a stop signal 604 issued from the control unit 63 and restarted by a start signal 603 (Fig. 7 (A)). When the timeout signal 605 of the window time W is output from the W timer 62 configured as shown in FIG.
At the same time as transmitting the TPDU, the W timer 62 is restarted (Fig. 7 (D)), and the timer 61 determines the inactivity time.
When the timeout signal 606 is output, the control unit 63
The connection opening procedure is started via
)) was like that.

[Problem to be solved by the invention]

However, in the conventional O3I transport protocol class 4 compliant communication control device, timers were provided to monitor the inactivity time I and the window time W, and these were restarted each time a TPDU was received and an AK TPDU was sent. So the processing time associated with the timer became longer.

It is therefore an object of the present invention to reduce the processing time associated with timers for monitoring inactivity and window times.
31) To provide a transport protocol class 4 compliant communication control device.

[Means to solve the problem]

In the present invention, in order to provide an OSI transport protocol class 4 compliant communication control device that reduces processing time associated with timers for monitoring inactivity time and window time, inactivity time I and window time W are respectively 2
A timer that outputs a timeout signal when it measures the time T (T = I/M, = I/N, ") divided by the above positive integer M0 and No CMo > No), and a timer that counts the timeout signal of the timer. When the connection between the first and second counters and the communication path is established, a timer is started and the first and second counters are set to 1, and when a TPDU is received, the first counter is set to AK.
When a TPDU is sent, the second counter is set to 0.
AK when the count value of the first counter becomes greater than the integer value M0, the connection is released, and the count value of the second counter becomes equal to or greater than the integer value N0.
TPDU is transmitted, and the count value of the first counter is an integer value M.
A control unit is provided that restarts the timer after timeout until the timer becomes larger than 0.

To reduce the number of timeout notifications, M
It is better for o and No to be relatively small, that is, for time T to be large. However, if Mo and No are made small (they cannot be made smaller than 2), the accuracy of time monitoring by the timer decreases. Therefore, considering the accuracy of time monitoring, W
It is desirable to set the value as large as possible within the range of /2 or less.

[Effect]

In the device of the present invention, the timer determines the inactivity time ■ and the window time W by positive integers M0 and No. of 2 or more, respectively.
Time T (T=I/M, divided by (Me > No)
=I/No), the timeout signal of the timer is counted by a first counter, and when the counted value becomes greater than Mo, the connection is released by the control unit. T.P.
When a DU is received, the first counter is reset to 0 by the control unit, so that the count value of the first counter becomes M.
It is time M without receiving a TPDU.

It means that T=I has passed. If a TPDU is received before the count value of the first counter becomes greater than Mo, i.e. before the time M, T=I has elapsed, the first counter is reset to O and the time T expires. Signal counting starts anew.

On the other hand, when the time-out signal of the timer is also counted by the second counter and the count value of the second counter is equal to or greater than No, the control unit outputs AK TP.
Send DU. Since the second counter is reset to O by the control unit when the AKTPDU is transmitted, the second counter is reset to O when the AKTPDU is transmitted.
The count value of the counter becomes equal to or greater than No at time N. Since this means that no AK TPDU has been transmitted until T=W, the AK TPDU is transmitted and the O3I protocol is satisfied.

As long as the count value of the first counter does not become larger than Mo,
Since the timer is restarted and continues to run, the above procedure can be performed until the connection is released.

A common timer is used to monitor the progress of the inactivity time I and the window time W, and a counter records the presence or absence of TPDU reception and AK TPDU transmission at time T, which is obtained by dividing ■ and W by an integer. Activity time I
TPDU reception during and AK during window time W
Since the presence or absence of TPDU transmission is determined, it is only necessary to reset the respective counters each time a TPDU is received and an AKTPDU is transmitted, and there is no need to restart the timer, so the processing time related to the timer is shortened.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

〔Example〕

An example of the 03I) transport protocol compatible communication control device according to the present invention is shown in FIG. 1. The communication control device in FIG. .

Timer 1 is a timer that measures a predetermined time T by receiving clock pulses from a clock pulse generator (not shown). The timer 1 receives a start signal 101 issued by the control unit 2 in response to the transport connection establishment signal TC.
When the time T elapses, a timeout signal 102 is generated. This timeout signal 102 is input to counter 3 and counter 4. Start signal 1
01 also means a restart signal, and timer l is the control unit 2.
It is restarted by the start signal 101 issued by the controller.

The counter 3 counts the timeout signal 102, and is set or reset to O or 1 by a set/reset signal 103 from the control unit 2. The count output 104 of the counter 3 is input to the comparator 5. As described later, the reset signal 103 is output when a TPDU is received and when a connection is released.

The comparator 5 compares the count output signal 104 of the counter 3 with a set value, and outputs an inactivity time elapsed signal 105 when the former becomes greater than the set value M. The inactivity time elapsed signal 105 is input to the control unit 2. When the control unit 2 detects the inactivity time elapsed signal 105, it releases the connection and simultaneously issues the set/reset signal 103.
Reset counter 3.

The counter 4 counts the timeout signal 102 and outputs a count output signal 107, which is set or reset to 0 or 1 by a set/reset signal 106 from the control section 2. The count output signal 107 of the counter 4 is input to the comparator 6.

The set/reset signal 106 is transmitted by the control unit 2 to the AKTPD.
It is output when U is sent, and counter 4 is reset.

The comparator 6 receives the count output signal 10 from the counter 4.
7 is compared with the set value N0, and when the former exceeds the set value N0, a window time elapsed signal 108 is output (N
, =W/T). The window time elapsed signal 108 is input to the control section 2. The control unit 2 receives the window time elapsed signal 1.
When detecting 08 (output of comparator 6), AK
Send TPDU.

The control unit 2 has the following functions.

(1) Upon receiving the transport connection establishment signal TC, the timer 1 is started by the start signal 101.

(2) When the transport connection establishment signal TC is input, set/reset signals 103 and 106 are generated, and counters 3 and 4 are set to 1, respectively.

(3) Upon receiving the TPDU, it sends a set/reset signal 103 to the counter 3 and resets it to 0.

(4) When the output signal 105 of the comparator 5 is detected, the transport connection is released.

(5) When the output signal 105 of the comparator 5 is detected, the set/reset signal 106 is supplied to the counter 4.

(6) When transmitting the AK TPDU, send a set/reset signal 106 to the counter 4 to reset it to 0.

(7) When the output signal 105 of the comparator 5 is not detected, the timer 1 is restarted by the start signal 101 regardless of the presence or absence of the output signal 108 of the comparator 6.

The operation of the above communication control device will be explained below with reference to the flowcharts of FIGS. 2 to 5.

Upon receiving the signal TC for establishing a transport connection, the control unit 2 starts timer 1 (201 in Fig. 2).
, 202), and set/reset signals 103, 106
are sent to counters 3 and 4, respectively, and counters 3 and 4 are set to 1, respectively. Each time the time T elapses, the timer 1 issues a time-out signal 102 for the time T.

The timeout signal 102 is input to the counter 3 and counted (501, 502 in FIG. 5), but the counter 3
When DU is received, it is reset to O by the set/reset signal 103 from the control unit 2 (301 in Fig. 3).
~303), the count of the counter 3 corresponds to counting the number M of (the timeout signal of) consecutive time T without TPDU reception occurring. The count value M of counter 3 is Mo
(503 in FIG. 5), the comparator 5 outputs a signal 105. This signal 105 is an inactivity time elapsed signal, and when the control unit 2 detects this, it releases the transport connection (504 in Fig. 5).
.

By the above operation, T during the inactivity time period is
The presence or absence of PDU reception is determined, and if no TPDU reception occurs during this time, the connection is released. because,
The count value of counter 3 means the number M of consecutive time T without receiving TPDU, but since count 1 is added at the time of connection establishment, this count value exceeds Mo during MOXT after connection establishment. Inactive time■
This is because the comparator 5 outputs the signal 105 at this time, and the connection is released by the control unit 2. In this way, the combination of the timer 1, the counter 3, the comparator 5, and the control unit 2 determines whether or not a TPDU has been received during the inactive time I, and based on this determination, the control unit 2 releases the connection. Note that the counter 3 is reset to O by the set/reset signal 103 when the connection is released, and prepares for the establishment of the next connection.

On the other hand, the timeout signal 102 from the timer 1 is input to the counter 4 (505 in FIG. 5).

After connection establishment, timeout signal 102 at time T
is counted by the counter 4, and a count output signal 107 is output. However, if AKTPDU is transmitted during this time, the counter 4 is reset by the set/reset signal 106, and the count value returns to 0 (402 in Figure 4 and 508 in Figure 5).
, thus the count of counter 4 corresponds to the number N of consecutive time intervals T without transmission of an AK TPDU. When the count value N of counter 4 becomes N0 or more (506 in Figure 5)
, a signal 108 is output from the comparator 6. This signal 108 is a window time elapsed signal, and is
detects this and sends an AKTPDU (Figure 5).
507).

Through the above-described operations, it is determined whether or not AK TPDU is transmitted during the elapse of window time W, and if AK TPDtJ transmission does not occur by the expiration of window time W, AK TPDU is transmitted. This is because, as mentioned above, the count value of counter 4 means the number N of consecutive times T without sending an AK TPDU, but since count 1 is added at the time of connection establishment, it is not possible for this count value to reach No. is after connection establishment (No-i)
This is because the comparator 6 outputs the signal 108 and the control unit 2 transmits the AK TPDU, which means that no AK TPDU was transmitted during x'r. In this way, timer 1, counter 4, comparator 6,
A combination of the control units 2 determines whether or not AK TPDU is to be transmitted until the window time W expires, and AK TPDU is transmitted based on this determination.

Timer 1 controls control unit 2 until the connection is released.
It is restarted every time out by the start signal 101 from (509 in FIG. 5).

Therefore, the time-out signal continues to be supplied for a time T until the connection is released, allowing the operations described above to be carried out.

Supplementary explanation will be provided regarding FIGS. 2 to 4.

FIG. 2 shows the procedure of the T-timer task executed by the device of the invention. When the T-timer task establishes a connection,
That is, it is activated at the start of the inactivity monitoring period, and provides a timeout notification every time T elapses. At the same time as the T timer task starts, the TPDU unreceived counter becomes 1 and the AK
A TPDU untransmitted counter (indicated as an AK untransmitted counter in the figure) is also set to 1, respectively. Above counter 3
corresponds to a TPDU non-reception counter, and the counter 4 corresponds to an AK non-transmission counter.

FIG. 3 shows a transmission task executed by the device of the present invention. When an AK TPDU is transmitted after a connection is established, the AK non-transmission counter (counter 4 in FIG. 1) is reset to 0, and AK TPDU transmission occurs. Record what you did.

FIG. 4 shows a reception task executed by the device of the present invention. After a connection is established, if a TPDU is received, the TPDU non-reception counter (counter 3 in FIG. 1) is reset to 0, and TPDU reception occurs. Record what you did.

FIG. 5 shows the procedure after the T timer expires, ie, the time T expires. This has already been explained together with the operation of the apparatus shown in FIG.

〔Effect of the invention〕

According to the OSI transport protocol class 4 compliant communication controller of the present invention, a common timer is used for monitoring the inactivity time and the window time, which are continuously restarted until the connection is released or the AK TPDU transmission is completed. , TPDU reception and AK TPDU transmission by counters, etc. are performed independently of timer restart, so compared to conventional devices for the same purpose, processing related to timers for monitoring inactivity time and window time is Time is saved and communication transmission delays are reduced.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the configuration of the O5■ transport protocol class 4 compatible communication control device of the present invention, FIG. 2 shows the procedure of the T-timer task executed by the device of the present invention, and FIG. FIG. 4 is an explanatory diagram showing the procedure of a sending task executed by the apparatus of the invention, FIG. 4 is an explanatory diagram showing the procedure of a receiving task executed by the apparatus of the invention, and FIG. It is an explanatory diagram showing a procedure after timeout. Fig. 6 is an explanatory diagram showing the configuration of a conventional O3 transport protocol class 4 compatible communication control device, and Fig. 7 is a procedure executed by the conventional O3 transport protocol class 4 compatible communication control device. FIG. Explanation of symbols 2--Control unit l--Timer 3.4--Counter 5.6---Comparator 61-- ----------I timer 62----W timer 63----Control section 101----Start signal 102--・
−・−・Timeout signal 103.106−−・−1−
−−・−Set/Reset 104・・・・・・・−・−・
Output signal of counter 3 105 --- Inactivity time elapsed signal 107 --- Output signal of counter 4 108
----------Window time elapsed signal 1------------I timer W timer 63---Control unit (AJ (DJ PDU KTPDU 7th Figure (B) (E) Figure 6 (C)

Claims (1)

[Claims] When the time T (T=I/M_0=I/N_0) obtained by dividing the inactivity time I and the window time W by positive integers M_0 and N_0 (M_0>N_0) of 2 or more, respectively, is measured. a timer that outputs a timeout signal; and first and second counters that count the timeout signal; when a communication path connection is established, starting the timer and setting the first and second counters to 1; When a TPDU is received, the first counter is set to AK
When the TPDU is transmitted, the second counters are respectively set to 0, and the count value of the first counter is set to the integer value M.
When it becomes greater than _0, release the connection,
when the count value of the second counter is equal to or greater than the integer value N_0, transmitting an AKTPDU;
A communication control conforming to OSI transport protocol class 4, comprising a control unit that restarts the timer after a timeout until the count value of the first counter becomes greater than the integer value M_0. Device.