JPH01151859A - Communication system - Google Patents

Abstract

PURPOSE:To allow the end system to save the processing relating to call interruption/resetting by bypassing a call communicated via a relay station to other route at a planned stop of the relay station. CONSTITUTION:A management table corresponding to a call used by end systems 41, 42 accommodated in each station and a call relayed by the station is provided to all stations (relay stations) 21, 22 being components of the network and the information of communication party of a call is stored therein. A relay station going to stop executes a bypass command of the call to the end systems 41, 42 of the relayed call based on the management table. End system accommodating stations 31, 32 receiving the bypass command from the relay station going to stop do not give no command to the end systems and reset the call between the end systems 41, 42 between the end system accommodation stations 31, 32 according to the management table (using a route not passing through the stop relay station). Thus, the load of the end systems 41, 42 relating to the call resetting is relieved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a communication system, and in particular to an automatic call diversion method that switches calls that have gone through the relevant relay station to calls on another route when a relay station is stopped. .

[Conventional technology]

When communicating using a circuit-switched network, two lines are used as a bypass method in case the line or relay station in the middle becomes unavailable.
Physical means such as weighting have been considered. However, with methods such as duplicating lines, one
The problem is that it must be maintained. In addition, as shown in Japanese Patent Application Laid-open No. 59-158192, there is a technology for continuation of a call when a terminal station to which an end system is connected stops, but a relay station that is not physically connected to an end system There was no mention of an effective detour method in the event of an outage.

[Problem that the invention seeks to solve]

In the above conventional technology, when a relay station that does not have a direct physical connection with the end system is stopped, no consideration is given to the maintenance/replacement of calls that are communicating using that relay station, and the relay station is stopped. When the line is switched/
It was necessary to reconfigure the call.

An object of the present invention is to allow calls communicating via the relay station to be easily handled by the network function when the relay station is stopped, without having to perform the five steps of call disconnection/resetting on the end system. Set up a detour/call to a route that does not go through the relay station you are trying to stop,
When the relay station is stopped, communication can be performed via a new route, so that the end system is not made aware of procedures related to call resetting, etc.

[Means for solving problems]

The above problem occurs at each relay station on the network.

It manages all call information that passes through the relay station, and when the relay station is stopped, it issues a call diversion instruction to the end systems of all the calls it was managing. The terminal station that accommodates the end system that received the call diversion instruction does not report this notification to the end system, and the terminal station sends the call to the other end system requested by the end system via another route. set up a call,
After the call setup is completed, by switching the existing call to the new call, the call can be diverted/reset without making the end system aware of the procedures related to the call diversion/resetup.

[Effect]

All stations (relay stations) that make up the network have management tables for calls relayed by call stations used by the end systems housed in each station, and store information such as the communication partner of the call. I'll keep it.

The relay station that is about to stop issues all call diversion instructions to the end system of the call it is relaying based on the information in the management table. The end system accommodating station that receives the call diversion instruction from the relay station that is about to stop does not notify the end system, but re-establishes calls between end systems among the end system accommodating stations according to the management table above (stopping). (using a route that does not pass through relay stations). After the detour/resetting of the call between the end system accommodating stations is completed, the end system accommodating station switches the existing call for the end system to a newly established call and releases the existing call. With this Kyo-Shiendo system, there is no need to be aware of the processing related to call resetting.

Further, the stopped relay station waits for the above-mentioned calls to be sequentially released, and after there are no more calls passing through the stopped relay station, the relay station is stopped.

This makes it possible to reduce the load on the end system related to call resetting.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which the present invention is applied to a circuit switching network capable of transmitting and receiving control information through a backward channel will be described below as an embodiment of the present invention with reference to the drawings.

In Figure 1, multiple stations (21, 22, A1, 32)
The end systems (111, 42) connected to the circuit switching network (1) configured as shown in FIG.
41 accesses the circuit switching network through 31, and 42 accesses the circuit switching network through 32), sets up a call, and performs communication between end systems.

The automatic call diversion method when a relay station is stopped in the above communication network will be described below with reference to FIG. 2.

sl, 32), FIG. 3 shows a call control table showing the status/attributes of calls passing through the station, and FIG.
The figure shows a route table that is necessary when setting up a call that passes between each station, and FIG. 5 shows an inter-office connection line control table that shows the state of the line between each station.

Figure 6 is a sequence chart when the relay station is stopped, Figure 7,
Figure 8 shows 70 at the relay station and end system accommodation station.
- Char) 1- Show and explain.

First, call setup between the two systems 41 and 42 will be explained.

A call setup request from the end system of 711 to 42 is 5
Passed to the first station. Since 42 is the end system of the 32nd station in the 31st station, the line is selected as follows. First, select the route table (72, Fig. a) J Niji and the line II for going to the adjacent station, and if the line has no problems from the inter-office connection line control table (751 Fig. 5), that line 1s'
5r is used to pass the call setup request to the adjacent station. Information at this time is recorded in the call control table (71°, Fig. 3). In FIG. 3, the input line and output line represent the types of lines shown at 51 and 52 in FIG. 22, 31, 52)
The alternate line is a line that is newly set when a call is automatically detoured, which will be explained later. Further, the identifier is information (for example, a telephone number) that uniquely indicates the end system.

Next, explain Figure 3. In FIG. 5, the first row represents transmission, the second row represents reception, and the third row represents relay.

Next, the processing method of the present invention will be explained based on the flowcharts of FIGS. 7 and 8.

As shown in Figure 6, the call between 41 and 42 is 41→31→22.
It is assumed that the route goes through →52 →42.

When the station 22 needs to stop the station (100).

The station 22 notifies the neighboring stations (21, 51, 52) of the suspension of station functions (101). The neighboring station that received this notification (200) should modify the tables shown in Figures 4 and 5 so that it will no longer set up or relay calls to station 22.
201) It is determined whether there is a call being set up to the station 22. 202) If so, the call is set up using another route (203). Here, no mention is made of means for propagating control information (open/stop notification in this example) between stations that does not use calls between end systems.

Next, at the station 22, the call control table on the station 22 (Fig. 5)
For calls that are being relayed, the backward channel of that call is used to instruct the end system to switch the call (102) () (By using the backward channel, only a specific call can be switched. call switching instructions). Next, the station 22 sets a certain timer to impose a certain time limit on automatic call diversion (1o3). Next, when either a timeout event or a release event of the current call on the station 22 occurs (106), the current call on the station 22 is released by the release procedure (304, 404) described below and either becomes OK or times out. 104), and when either condition is met, the station is stopped (105). Setting the timer is recommended when automatic call diversion cannot be performed completely and
This is to avoid all situations where 2 cannot be stopped.

Further, detour designation using a backward channel is instructed to the call setting side (input line side). This is because issuing detour instructions to both end systems complicates the procedure when setting up a new call.

The call diversion instruction from the station 22 is logged by the station 51, and the automatic call diversion process of the station 31 is started (500
) (this notification does not notify the end system).

Next, based on the call control table (Figure 3) of the station 51, it is possible to determine which call should be automatically diverted (including the communication partner), so a preferred call setup request can be sent to this information as well. A call is made to the system (301).

At this time, this call setup request clearly indicates that it is a detour instruction. Also, the times I selected at this time! It is recorded in the alternate line of the call control table in all stations 31.

Call setting request (detour instruction pair) from station 51 is sent from 31→21→
A station that received 32 routes! At +2, call bypass processing on the receiving side is activated (400).

First, at this point, the end system is communicating via the route 31→22→32, so the station 32 performs normal call setup on its behalf (401). However, the call control table on the station 32 uses the table of currently existing calls, and like the station 31, the line information of the new call is recorded as the alternate/alternative line K of the current call.

After the normal call setup is completed, the station 31 sends a call switching instruction to the station 32 (502). In response, the station 32 switches the existing call to a newly established call (402) and sends a completion notification to the station 31 (405). Upon receiving the notification of completion, the station 31 switches the existing call within the station 31 to a newly established call (402) and sends a notification of completion to the station 31 (4O3). Upon receiving the notification of completion, the station 31 switches from the existing call to the newly established call within the station 51 (SOS). Also, when the switching from the current call to the new call is completed for both station 511 and station 32, the current call is released (304.degree. 404).

〔Effect of the invention〕

According to the present invention, when a relay station is scheduled to be stopped (for maintenance, etc.), calls communicating via the relevant relay station can be maintained without the need for call resetting procedures by the end system. Since the call can be detoured to a different route, the end system process related to call disconnection/resetting can be omitted.

[Brief explanation of the drawing]

FIG. 1 is a circuit switching network system diagram of an embodiment of the present invention, FIG. 2 is a block diagram showing the internal structure of the stations (31, 32, 21, 22) in FIG. 1, and FIG. FIG. 4 is an explanatory diagram of the route table within the station, FIG. 5 is an explanatory diagram of the inter-office connection line control table within the station, and FIG. 6 is a sequence chart of the embodiment of the present invention. , Fig. 7, Fig. 8
The figure is a flowchart at each station based on the sequence chart of FIG. 1... Circuit switched network, 21, 22, 'A, 52... Station, 41,
42...End system, 51...End system accommodation line, 52...Synonym for use between adjacent stations, 61...Station control device, 71...Call control table, 72...Route table, 73...・Inter-station connection control table.纂 1 Figure 31.32 End V station, mu, increase Jwaq41, now 2
End system, Mu, Easy 2nd tile/frame Ka 3rd figure +Iz 5th time 77 (a) 8th Z mark)

Claims (1)

[Claims] 1. A communication system characterized by a circuit-switched communication network consisting of a plurality of stations having a call setting function, and two or more end systems that communicate using this network.