JPS60167543A - Circuit switching system - Google Patents

Abstract

PURPOSE:To attain a instantaneous switch to a spare circuit corresponding part by transmitting an action mode setting inducement response from a packet exchange every fixed interval and giving initialization to a data link set between the packet exchange and a terminal circuit. CONSTITUTION:A switching action to a spare circuit corresponding part 2b is carried out as follows. At the outset, a CPU1 sends a parameter designating signal 10 to the part 2b to attain a presently desired action. Then the CPU1 transmits an action mode setting inducement DM command 5 to the part 2b so as to transmit continuously the DM responses 6 in a connection mode to a circuit 3. No response 6 is transmitted since the circuit 3 is not connected physically to the part 2b before the connection is switched to the part 2b. Then the CPU1 delivers a switching preparatory end report 11 which shows that the preparatory is through with switching to the part 2b. Then a working circuit corresponding part 2a is switched to the part 2b by a switching signal 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] In switching lines in a packet switch, the present invention initializes the line to be switched before switching.

Set state and times! Also regarding the method of switching.

It is. In particular, it concerns a switching system suitable for switching 5 lines according to the X.25 Recommendation before 1980.

be.

[Background of the invention]

Micropro due to the recent development of LSI technology.

Lf9I and large-scale memory devices for communication, including processors, are emerging.

A central control processing unit is also used in packet switching equipment.

Everything about the packet switch in f (CPU).

Conventional packet switching equipment performs control and processing.

ccITT Recommendation-X1'25 has now been sent to the line support department.
Packet switching equipment that distributes level 2 processing is emerging.

In this latter packet switch, if it becomes necessary to replace the line response part, we will replace it.

Naturally, it becomes necessary to accommodate the lines accommodated in one section in another line corresponding section. Upon this replacement,

The line housed in the line support section to be replaced is working.

In consideration of the case where a communication is in progress, the line handling section
Control information regarding "TCITT Recommendation Bell 2".

It is necessary to take over the information.

However, this transfer requires memory copying, etc.

Requires a transmission means and is expensive in terms of hardware.

Therefore, a method is often adopted in which the line accommodated in the line handling section waits until the end of communication and then replaces it. 1. However, in packet switching equipment that does not implement call security charging, there are generally many lines that continue to be in a communication state, so the waiting time until communication ends is naturally often long. .

In addition, in order to shorten this waiting time, there is a method of executing the exchange regardless of whether communication is in progress, but as mentioned above, the control information of "X25 level 2" is inherited. Communication may be disconnected due to communication being interrupted.

Therefore, the above-mentioned replacement method has the disadvantage that the maintenance function and serviceability of the packet switch are significantly reduced.

was there.

[Purpose of the invention]

The object of the present invention is to accommodate the current line support unit.

communication when switching over lines (especially lines 5 that comply with Recommendation

When it was disconnected, it was possible to switch immediately.

The purpose of the present invention is to provide a source switching method. .

[Summary of the invention]

The line switching system of the invention switches all lines housed in the active line handling unit 10 to the backup line handling unit.

``CCI'l'T Recommendation dX
25 level 2'' operation mode setting.

Transmits Subonsu at regular intervals and exchanges packets.

This feature is characterized in that line switching is performed while the data link between the machine and the terminal is being initialized.

[Funny example of invention]

The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a 2° overall system diagram for explaining the line switching system of the present invention, and FIG. 2 is a flowchart for explaining it. In the figure, 1 is the central control processing unit (CPU) in the packet switch, 2'a is the active line support unit, and 2b is the backup line support.

3 is a line accommodated in the current line support unit, and 4 is a line 3 that is transferred from the current line support unit 2a to a spare line.

A switching instruction signal ζ5 instructing the line handling unit 2b to switch is an operation mode setting invitation command signal instructing the line handling unit 2a (or 2b) to send an operation mode setting invitation response (DM) f. Response (DM) 7, which means mode setting solicitation, is in response to DM response 6, and “CC Engineering TT Recommendation
5 Level 2”.

Initialize data link status and operation mode.

SABM (asynchronous balanced mode) which means a mode setting request
command, 8 is a data transmission ready report signal indicating that SABM command 7 has been received and the state is ready for further communication, and 9 is a UA (unnumbered) indicating that SABM command 7 has been received. Confirmation/Acknowledgment) Response, 10 is CP
A path that notifies U1 of the status parameters for which the line pair response section should operate.

The parameter designation signal 11 indicates that both the active line corresponding section 2a and the standby line corresponding section 2b are ready for switching.

12 is the line.

3 is a switching signal 13 for switching from the current line support unit 2a to the standby 5 line support unit 2b.

Off indicates that the switching work has been completed and communication has resumed.

This is a change completion report signal.

Next, the operation will be explained using the switching sequence shown in FIG. ]0 When the CPUI receives switching instruction 4, it switches to the current CPUI.

The line handling section 2a starts the operation for switching.

Transmit the operation mode setting solicitation command 5 for the current line support section 2a to send the operation mode setting solicitation command 5.

When you receive cloak 5, DM response to line 3 + 5 messages 6
Send. Naturally, a packet terminal is connected to the end of the line 3, but the explanation below will continue on the assumption that transmission and reception will be performed between the packet terminal and the packet terminal.

Line 3 is 8A21) BM for the DM response 6.
Respond to command 7. Current line support section.

2a receives the SABM command 7.

The execution of the resetting command 5 is completed, and '8AB
M command 7 C in the sense that it was received.

Data transmission permission report signal 8 is sent to PUI, and UA is sent to line 3.
Sends response 9. Here, C'PUI is between the current line corresponding section 2a and the line 3.

This means that you have received a report that the initial settings for the data link have been completed.

However, in order to carry out the switching, it is necessary to continue the initial state of 1''.

- Repeat the above operation for each construction time. -Next, the operation for switching to the backup line support section 2b will be explained. First, the CPUI sends a parameter designation signal 10 to the backup line/line pair 2b so that it can operate as a working line. Then, when connected to line 3゜]) M response 6 times ff! Continue to A3.

to the spare line support section 2b for subsequent transmission.

The operation mode setting invitation command 5 is sent. The spare/backup line support section 2b invites the setting of the operation mode, . . .

When the cloak 5 receives the DM response 6, the DM response 6 is sent to the line 3, but the DM response 6 is not connected to the line 3 in the state before switching.

It is physically connected to the spare line corresponding section 2b.

DM response 6 is not sent because there is no such person. ``Here, the backup line support unit 2b reports a switching preparation completion report 11 from CP'Ul indicating that the preparation for switching has been completed. CPU1 is ready for switching.

After transmitting 11% of completion reports, a data transmission ready report signal 8 is received from the backup line correspondence section 2b' indicating that communication with the line 3 can be started for 10 seconds.

From the current line support unit 2a to the backup line support unit.

Switching to 2b is carried out by a switching signal 12. .

As a result of this switching, the line 3 is physically connected to the backup line support section 2b', and a SABM command door is sent to the DM response 6 from the backup line support section 2b or 15.

When the spare line support unit 2b receives the command 7, it sends a data transmission/communication report signal 8 to the CPUI and a UA response 9 to the line 3. 20 The CPUI is now in a state where it is possible to resume communication between the spare line support unit 2b and the line 3'.

The switching end report signal 13 is sent out. .

Here "i?, l' - CCI'rT Recommendation - X25 Level 2
”.

The switching is completed while the line 3 continues to be set to the initial setting state, and the line 3 and CPU 1 are able to communicate again.

Also, a switching instruction signal 4 to CI) U l, CPU.

Switching preparation completion report signal 11 from 1, switching completion report 1
The third party is, for example, a packet switch, although the description thereof will be omitted since it does not fall within the scope of the present invention.

maintenance typewriters etc.゛[Effects of the invention] As is clear from the above-mentioned embodiments, the invention is applicable to the present invention.

According to ``CCITT Recommendation X25 Level 3-J and above, when switching from the old line to the standby line corresponding part of the active line pair 1 in a packet switch, the effect of the switch should be instantaneous. It is possible to maintain the communication without causing any damage, which significantly improves maintainability and serviceability.

[Brief explanation of drawings]

FIG. 1 shows a line switching system for explaining the present invention. FIG. 2 is a switching sequence diagram. . DESCRIPTION OF SYMBOLS 1... Central control processing unit, 2a... Current line support unit, 5 2b... Backup line support unit, 3... Line, 4... Switching instruction, 5... Operation mode setting Foot invitation command, 6... DM response, 7... 8 ABM command signal, +08... Data transmission possible report signal, 9... UA response, 10... Parameter finger/foot signal, 11... Switching preparation completion report signal, 12... Switching signal, +5 13... Switching completion report signal. Figure 1 Figure 2

Claims (1)

[Claims] In a line switching system in a packet switch in which processing up to the CCITT recommendation "X25 level 2" is performed in the line handling unit, any line stored in the active line handling unit can be used as a backup. When switching to the line support section, the current line support section is sent from the packet switch 1 to the current line support section so that it continues to send frames, which mean to solicit operation mode settings, to the line at regular intervals until the switching is completed. At the same time, after the above-mentioned line switching is completed, a frame is sent to the standby line support unit, which means an invitation to set the operation mode to the line, until the frame switching is completed and communication is resumed. The packet switch sends an instruction signal to continue switching, and after the switching is completed, the "CCITT Recommendation... A line switching method characterized by restarting communication.・