JPH0691676B2 - Control method of distributed control type electronic exchange - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a control system for a distributed control type electronic exchange, and more particularly to a distributed control type electronic system capable of restricting the use of outgoing connection trunks to subsystems during congestion. The control system of the exchange.

[Background of the Invention]

Conventionally, in a centralized control type electronic exchange composed of a single processor, resource management of outgoing and incoming routes can be performed centrally in outgoing connection control, that is, capture control of an output trunk. However, in a distributed control type electronic exchange composed of a plurality of subsystems, the same route is connected to a plurality of subsystems, so that resource management cannot be performed independently in each subsystem. Therefore, conventionally, for example, the following means have been taken.

(1) Provide a dedicated subsystem for managing the outgoing and incoming routes (see "FUJITSU" Vol.34, No.1, 1983, p34-67).

(2) A common memory shared by each subsystem is provided to manage outbound connection control (“NEC Technical Report” Vol.34, No.9, 198)
1, p14-21).

In the above conventional technique, the processing at the time of congestion is also managed by these common devices. However, according to these conventional methods, there are problems such as a decrease in processor capacity due to an increase in communication amount between processors, an increase in call delay time, and an increase in the spread of failures, which reduces the advantages of distributed control. Met. As an exchange that excludes the above-mentioned common device, for example, PABX / MD110 by Ericsson is known (ICC'84, Vol.2, 17.5), but communication outgoing / connection management is not performed.

[Object of the Invention]

An object of the present invention is to provide a fully decentralized control type capable of avoiding capture of an outgoing connection trunk passing through a subsystem in an overloaded state without installing a dedicated device for managing outgoing and incoming routes. To provide a control system for the exchange.

[Outline of Invention]

In order to achieve the above object, in the control system of the present invention, on each storage device of the plurality of subsystems constituting the distributed control type exchange, information indicating the presence or absence of congestion state of all subsystems (congestion information) To remember
When a subsystem becomes congested, it immediately notifies all other subsystems, and each subsystem that receives the notification rewrites the congestion information stored in its own storage device. By controlling the outgoing connection with reference to the information, it is possible to avoid capturing the outgoing / incoming trunk passing through the congestion subsystem until the congestion state is resolved.

Example of Invention

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

FIG. 1 shows a plurality of local switch subsystems 1, 2, 3 as an example of a distributed control type exchange according to the present invention.
And a tandem switch subsystem 4 connecting these local switch subsystems to each other (A
Station).

The local switch subsystems 1, 2, and 3 accommodate subscriber lines, trunks, and the like, are provided with a main memory device 5, a central control device 6, and a switch 7, and each function as an independent exchange. The local switch subsystem and the tandem switch subsystem are connected by a digital highway 11. Outgoing connection trunks connected to the B station are accommodated in the plurality of local switch subsystems 1, 2, and 3 on the A station side in consideration of risk distribution.

Here, assuming that the subscriber 10 accommodated in the local switch subsystem 1 makes a call to the subscriber accommodated in the station B, the subsystem 1
The capture processing of the outgoing / incoming trunk 9 performed by will be described with reference to FIG.

In the subsystem 1, when the outgoing connection call is established as a result of the dial reception from the subscriber 10, the trunk acquisition program shown in FIG. 2 is activated.

In the trunk acquisition program, first, it is determined whether or not the outgoing connection trunk requested to be connected is included in the subsystem, and if so, the trunk is acquired, and if not, the "route" stored in the memory 5 is stored. Based on the "empty table", it is determined whether or not there is an empty trunk in the other subsystem 2 or 3, and if there is an empty, a start signal is sent to that subsystem. To do.

As shown in FIG. 3, for example, the “route empty / closed table” has a storage bit corresponding to the local switch subsystem number (LSSNO) for each route number (TGN). State (congestion information) of 1 bit (“0” /
It is stored as "1"). A table similar to this is A
It is provided in all local switch subsystems of the station, so that all subsystems can determine which subsystem the trunk of the requested route number is in the empty state.

When each subsystem has an overload condition, for example, when the processor utilization exceeds a certain reference value, each subsystem has a function of restricting (blocking) a request for seizing an outgoing connection trunk addressed to itself. The congestion notification signal is transmitted to all the subsystems.

Each subsystem, when receiving the congestion notification signal from other subsystems, activates the congestion signal receiving program,
For example, the corresponding bit (congestion notification signal source subsystem number LSSN) of the "congestion table" shown in FIG. 4 prepared on the storage device for storing the presence or absence of congestion for each subsystem
(Bit corresponding to O) is set to "1", and the congestion occurrence subsystem number LS is set in the "route blockage table".
Set the congestion information bit of all routes corresponding to the SNO to "1". In addition, when a full route busy occurs, the "route full busy table" having the same configuration as the route empty block table in FIG. 3 corresponds to the route number and subsystem number at which the full busy occurs. In addition to setting the display bit to, the congestion information is set in the route blockage table.
That is, these tables have a relationship of "route empty block table" = "route full busy table" or "congestion table".
Also, when one subsystem is released from congestion and a congestion release signal is sent to another subsystem, the bit of the corresponding subsystem in the "congestion table" is "0" in each subsystem.
Is set to, and the value of "route all busy table" is set to "route empty block table".

As a result of the above, when congestion occurs in a certain subsystem, until the congestion is released, another subsystem regulates the supplement of the outgoing connection trunk to the congestion subsystem.

〔The invention's effect〕

According to the present invention, in a fully distributed control type exchange that does not have a common device that manages resources for outgoing connections, by restricting the capture of outgoing connection trunks of subsystems in a congested state, Can be distributed to each subsystem.

[Brief description of drawings]

DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an example of a configuration of a distributed control electronic exchange to which the present invention is applied, FIG. 2 is a diagram showing a main part of an outgoing connection trunk capturing routine, and FIG. 3 is each subsystem. 5 is a diagram showing the configuration of a "route empty block table" and a "route full busy table" stored in the main storage device of FIG. 4, and a diagram showing the configuration of a "congestion table" of the subsystem in FIG. 4. FIG. [Explanation of symbols] 1, 2, 3 ... Local switch subsystem, 4 ... Tandem switch subsystem, 5 ... Main memory device, 7 ... Time division switch, 8 ... Digital highway, 9 ... Out connection Trunk, 10 ... Subscriber

Claims (1)

[Claims] 1. An interconnection system comprising a plurality of subsystems each having an independent switching function, each subsystem being capable of capturing an outgoing / incoming route by selectively passing through one of the plurality of subsystems. In the distributed control type electronic exchange, each subsystem is provided with a table means for storing the presence or absence of congestion status of all subsystems corresponding to the outgoing connection route, and the load status of the own subsystem or accommodation The subsystem whose usage status of the outgoing connection route exceeds a predetermined standard notifies the congestion information to all other subsystems, and each subsystem responds to the congestion information received from the other subsystem as described above. Update the contents of the table means,
By referring to the above table means at the time of call connection,
A control system for a distributed control type electronic exchange, characterized in that a required route avoids a subsystem in a congested state to capture an outgoing connection route.