JPH04223800A - Isdn exchange system - Google Patents

Abstract

PURPOSE:To improve reliability by giving an inter-remote node communication line connection control means, an asynchronous transfer mode communication means and a bus switching means and executing exchange service with an ISDN subscriber network system. CONSTITUTION:Subscriber storage nodes 2-1 store plural subscribers 1-1. Exchange connection nodes 2-3 connect communication buses between the nodes 2-1 and exchanges 1-3 and the nodes 2-3 are connected with the exchanges 1-3 by transmission lines 1-5, and are connected to ring access devices 2-2 by CN connection circuits 2-6. A control node 2-4 operates and controls the subscriber network system 2, the node 2-4 is connected to the device 2-2 through an MN connection line 2-7 and controls the nodes 2-1 and 2-3 through RAE connection transmission lines 2-8 and the devices 2-2. The devices 2-2 connect the communication buses between the nodes 2-1, between the nodes 2-1 and the nodes 2-3, between the nodes 2-4 and the nodes 2-1 via a transmission line 2-8. Thus, a highly reliable ISDN conversion system can be constructed.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a communication network switching system,
In particular, the Integrated Services Digital Network Switching System (ISDN)
exchange system).

0002

[Prior Art] As a conventional technology of ISDN exchange system, for example, Hiroshi Ishikawa, "ISDN at NTT"
Journal of the Institute of Electronics, Information and Communication Engineers, Vol. 73, No. 3, No. 197-2
There is one described on page 02. FIG. 10 shows an example of the configuration of such a conventional ISDN switching system.

As shown in the figure, this system includes a concentrator stage for providing switching services to analog telephone subscribers, and an I-interface subscriber system module ISM for providing switching services to ISDN subscribers. ,
A D70 switching system is installed, consisting of distribution stages with common functionality for providing switching services to analog telephone subscribers and ISDN subscribers. Also,
For ISDN subscribers located far from the switching center, a remote multiplexer RT1 and a remote multiplexer 1.5MRT are provided for accommodating a plurality of subscribers and transmitting multiplexed data between them and the switching center via a digital transmission path. A multiplexer, called a multiplexer, is located at the remote station.

These multiplexing devices have a function of multiplexing subscriber line transmission signals onto a digital transmission line and a function of distributing the multiplexed transmission signal of the digital transmission line to the subscriber line. Exchange services for people are provided through exchanges.

[0005]

[Problems to be Solved by the Invention] However, in such a conventional ISDN switching system, the connection form between the switching center and the remote station is a star connection configuration, and the switching service for switching center subscribers is limited to the call processing of the switching center. It was provided using functions and exchange functions. Also, remote stations were connected to belong to one exchange. For this reason, if the exchange system goes down, the exchange service for all subscribers accommodated at the remote station will be interrupted, and if the transmission line or the remote station support section of the exchange breaks down, exchange service for the subscribers accommodated at this remote station will be interrupted. The problem arises that the process is interrupted. As described above, the conventional ISDN switching system has the disadvantage that reliability in the event of a failure is low, and that the impact on society when a problem occurs is extremely serious.

[0006] The present invention provides a system having an autonomous switching function in order to eliminate interruptions in switching services for subscribers accommodated at remote stations when the switching center system goes down, transmission line failures, and remote station corresponding parts of the switching center fail. By configuring the system to connect remote stations to exchanges, highly reliable IS can be achieved.
The purpose is to provide a DN exchange system.

[0007]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention consists of a switch installed in a switching center and a remote node installed in a remote station accommodating remotely located subscribers. The remote nodes of I are connected by a transmission path.
In an ISDN switching system that constitutes an SDN subscriber network system, a plurality of remote nodes having call processing means and communication line switching means for providing switching services to accommodated subscribers are connected in a ring type. a remote node communication line connection control means for providing an exchange service between the subscribers accommodated by each remote node connected to the ring; an asynchronous transfer mode communication means that transfers information between a remote node and a plurality of exchanges; and an asynchronous transfer mode communication means that transfers information between a remote node and multiple exchanges; The ISDN subscriber network system can autonomously provide switching services, and the connection relationship with a plurality of switching stations can be made variable.

[0008]

[Operation] According to the present invention, a test is performed on the connected first switching center and second switching center to confirm the normality of the communication path, and if the test on the first switching center is normal, this Continue to belong to the exchange. In addition, if the test result for the first exchange is abnormal, and the test for the second exchange is normal, the path for transitioning from the first exchange to the second exchange will be determined. Change the connection.

[0009]

[Example] Next, referring to the attached drawings, an ISD according to the present invention will be described.
An embodiment of the N exchange system will be described in detail.

FIG. 1 shows an ISDN in an embodiment of the present invention.
FIG. 1 is a system configuration diagram showing an example of the configuration of an exchange system. The ISDN switching system in this embodiment includes a plurality of subscriber network systems (SNS) 2-1 and 2-2, as shown in the figure.
The network consists of one switching center 1-3.

The subscriber network system 1-2 is a device that accommodates a plurality of subscribers 1-1 and connects communication lines between the accommodated subscribers and between the accommodated subscribers and the switching center. The subscriber network system 1-2 accommodates a subscriber 1-1 constituted by, for example, a network termination device NT and a terminal device TE via a subscriber line 1-4, and receives a selection signal from the terminal device TE. Connect the communication line. Each subscriber network system 1-2 is connected to two exchanges 1-3 by transmission lines 1-5, as shown in the figure.

The exchange 1-5 is an exchange that accommodates a plurality of subscribers and a plurality of subscriber network systems and controls connections of communication lines. The switching center 1-5 has a communication between accommodated subscribers 1-1,
Communication lines between accommodated subscriber 1-1 and subscriber network system 1-2, between accommodated subscriber 1-1 and other stations, between subscriber network system 1-2 and between subscriber network system 1-2 and other stations. connection control. Note that the subscriber line 1-1 connects the subscriber 1-1, the subscriber network system 1-2, and the exchange 1-3.
4 and a transmission line 1-5 connecting the subscriber network system 1-2 and the switching center 1-3 is composed of a reception line and a transmission line.

FIG. 2 shows an example of the configuration of the subscriber network system 1-2 in this embodiment. As shown in the figure, the subscriber network system 1-2 includes a plurality of subscriber accommodating nodes (SN) 2-1, a plurality of switching center connecting nodes (CN) 2-
3, a management node (MN) 2-4 and a ring access device (RAE) 2-2.

[0014] The subscriber accommodating node 2-1 accommodates a plurality of subscribers 1-1.
1 and other subscriber accommodating node 2-1 and between accommodating subscriber 1-
This is a device that connects between the switching center connection node 1 and the switching center connection node 2-3. The subscriber accommodating node 2-1 is connected to the subscriber 1-1 via the subscriber line 1-4 and the SN connection line 2-1.
5 is connected to the ring access device 2-2.

The exchange connecting node 2-3 is a device that connects a group of communication lines (hereinafter referred to as a communication path) between the subscriber accommodation node 2-1 and the exchange 1-3. The switching center connection node 2-3 is connected to the switching center 1-3 via the transmission path 1-5,
It is connected to the ring access device 2-2 by a CN connection line 2-6.

The management node 2-4 is a subscriber network system 1.
-2 is a control device for operation and management. The management node 2-4 is connected to the ring access device 2-2 via the MN connection line 2-7, and is connected to the subscriber accommodation node 2-2 via the RAE connection transmission path 2-8 and the ring access device 2-2.
1 and switching center connection nodes 2-3.

The ring access device 2-2 connects the subscriber accommodating node 2-1 via the RAE transmission path 2-8, between the subscriber accommodating node 2-1 and the switching center connecting node 2-3, and between the management node 2-1. 4 and the subscriber accommodating node 2-1. Note that the line and transmission line connecting these devices, that is, the SN connection line 2-
5. CN connection line 2-6, MN connection line 2-7 and R
The AE transmission line 2-8 is composed of a reception line and a transmission line.

FIG. 3 shows an example of the configuration of the subscriber accommodation node 2-1 in this embodiment. As shown in the figure, the subscriber accommodation node 2-1 includes a plurality of subscriber line termination devices (
SLTE) 3-1, ring interface equipment (RIE)
) 3-4, a call processing device (CPE) 3-3, and a switching device (SWE) 3-2.

Each subscriber line termination device 3-1 is connected to a plurality of subscribers 1-1 via a subscriber line 1-4, and is also connected to a switching device 3-1 via an SLTE connection line 3-5.
2 and performs the following processing. (1) Terminate subscriber line 1-4 and SLTE connection line 3-5 and extract fixed-length information blocks called cells. (2) Based on the extracted cell header information, subscriber line 1-
4, the subscriber signal cells on the subscriber signal cell transfer virtual line (hereinafter referred to as SV line) and the communication information cells on the communication cell transfer virtual line (hereinafter referred to as UV line) are separated. do. (3) Subscriber signal transfer set between subscriber line termination device 3-1 and call processing device 3-3 by adding a path header to the subscriber signal cell on the SV line corresponding to subscriber 1-1 SV path (hereinafter referred to as SV path). (4) A communication virtual path (hereinafter referred to as (referred to as UV path). (5) Multiplex the subscriber signal cell of the SV path and the communication information cell of the UV path on the SLTE connection line 3-5 and transmit it to the switch device 3-2. (6) Separate the subscriber signal cells of the SV path and the communication information cells of the UV path that are logically multiplexed on the SLTE connection line 3-5. (7) Separate subscriber signal cells logically multiplexed on the SV path into SV line units corresponding to subscribers. (8) Separate the communication information cells logically multiplexed on the UV path into UV line units corresponding to subscribers. (9) The subscriber signal cell of the SV line corresponding to subscriber line 1-4 and the communication information cell of the UV line are logically multiplexed and transmitted.

[0020] The ring interface device 3-4 is an SN
It is connected to the ring access device 2-2 via the connection line 2-5 and to the switch device 3-2 via the RIE connection line 3-7. The ring interface device 3-4 terminates the SN connection line 2-5, extracts cells, and transmits the cells to the switch device 3-2 via the RIE connection line 3-7. Ring interface device 3
-4 also terminates the RIE connection line 3-7 to extract cells, and transmits the cells to the ring access device 2-2 via the SN connection line 2-5.

[0021] The call processing device 3-3 connects the CPE connection line 3-
6 and the SWE control line 3-2 to the switch device 3-2, and performs the following processing. (1) Terminate the CPE connection line 3-6 and extract cells. (2) Subscriber terminal device 3-1 via switch device 3-2
from the subscriber signal cell carried by the SV path from S
It assembles subscriber signals compatible with the V line and executes call processing. (3) Control information cell transfer virtual path (hereinafter referred to as CV path The controller assembles control information from the control information transmitted by the controller and performs call processing. (4) Assemble the subscriber signal to be sent to the subscriber 1-1 into a subscriber signal cell compatible with the SV line, and
The signal is logically multiplexed onto the SV path set to correspond to 1 and sent to the CPE connection line 3-6. (5) Assemble control information to be sent to other subscriber accommodating nodes 2-1, management nodes 2-4, and exchanges 1-3 into control information cells, and
Then, it is sent to the CPE connection line 3-6 via the CV path set corresponding to the switching center 1-3. (6) UV line of the switching device 3-2 based on call processing execution results and path setting control information from the management node 2-4;
Controls the connection of the SV path and CV path.

The switch device 3-2 performs the following processing. (1) SLTE connection line 3-5, RIE connection line 3-
7 and CPE connection line 3-6 are terminated and the cells are sent out.

(2) Cells are exchanged between the following paths based on connection control information from the call processing device 3-3. ■SLTE connection line S
Cell on V path and CPE connection line Cell on SV path■S
Cells on the UV line logically multiplexed to the LTE connection line UV path and U logically multiplexed to other SLTE connection line UV paths
Cells on the V line ■ SLTE connection line Cells on the UV line logically multiplexed on the UV path and RIE connection line Cells on the UV line logically multiplexed on the UV path ■ RIE connection line Cells on the CV path and CPE connection line Cells on the CV path Furthermore, the SLTE connection lines 3-5 and RI that connect these devices
E connection line 3-7, CPE connection line 3-6 and SWE
The control line 3-8 is composed of a reception line and a transmission line.

FIG. 4 shows an example of the configuration of the exchange connecting node 2-3 in this embodiment. As shown in the figure, the exchange node 2-3 has a ring interface device (R
IE) 4-1, exchange center interface equipment (CIE) 4
-3 and a switch device (SWE) 4-2.

[0025] The ring interface device 4-1 is a CN
It is connected to the ring access device 2-2 via the connection line 2-6, and also connected to the RIE connection line 4-4 and SWE.
It is connected to the switch device 4-2 by a control line 4-6. The ring interface device performs the following processing. (1) Terminate the CN connection line 2-6 and extract cells. (2) Subscriber accommodation node 2- on the CN connection line CV path
1 to the switching center 1-3 is transmitted to the switching device 4-2 via the RIE connection line 4-4. (3) Transfer the SWE control cell from the management node 2-4 on the CN connection line CV path to the switching device 4-2 via the SWE control line. (4) Terminate the RIE connection line and switch device 4-3
, and sends the cells to the ring via the CN connection line.

The exchange interface device 4-3 is connected to the exchange 1-3 via the transmission line 1-5, and
It is connected to the switch device 4-2 by a CIE connection line 4-5. The exchange interface device 4-3 performs the following processing. (1) Terminate the transmission line 1-5 connected to the exchange 1-3, extract the received cell from the exchange 1-3, and transmit the cell to the switch device 4-2 via the CIE connection line 4-5. . (2) Terminate the CIE connection line 4-5, extract the received cell from the switch device 4-2, and transmit the cell to the exchange 1-3 via the transmission path 1-5.

The switch device 4-2 performs the following processing. (1) RIE connection line 4-1 and CIE connection line 4-
5 is terminated and the cell is extracted. (2) Based on the connection control information from the management node 2-4, cells are exchanged between the following paths. ■Cells on the RIE connection line CV path and cells on the CIE connection line CV path ■Cells on the RIE connection line UV path and CIE connection line U
Cells on the V-Path Note that the RIE connection line 4-4, SWE control line 4-6, and CIE connection line 4-5 that connect each device are composed of a reception line and a transmission line.

FIG. 5 shows the management node 2-
4 shows an example of the configuration. As shown in the figure, the management node 2-4 has a ring interface device (RIE).
) 5-1 and a system management device (MNE) 5-2.

[0029] The ring interface device 5-1 is an MN
The connection line 2-7 connects the ring access device 2-2 and the M
It is connected to the system management device 5-2 by an NE connection line 5-3. The ring interface device 5-1 is M
Terminate the N connection line 2-7 and connect it to the subscriber accommodation node 2-1.
, switching center connection node 2-3 and ring access device 2
-2, and transmits this cell to the system management device 5-2 via the MNE connection line 5-3. The ring interface device 5-1 also terminates the MNE connection line 5-3, extracts cells to be transmitted to the subscriber accommodation node 2-1, the exchange connection node 2-3, and the ring access device 2-2, This cell is sent out to the ring via the MN connection line 2-7.

The system management device 5-2 is a device that operates, manages, and tests the system. That is, the system management device 5-2 performs a normality test of the switching system and the inter-exchange communication path using the exchange-exchange test CV path set between the system management device 5-2 and the exchange 1-3. System management device 5
-2 also performs connection control of the switch device 6-2 (see FIG. 6) provided in the ring access device 2-2. Note that the MNE connection line 5-3 is composed of a reception line and a transmission line.

FIG. 6 shows an example of the configuration of the ring access device 2-2 in this embodiment. As shown in the figure, the ring access device 2-2 includes two transmission line interface devices (TIE) 6-1, a node interface device (NIE) 6-3, and a switch device (SWE) 6-2.
It is made up of.

Each transmission line interface device 6-1 is connected to another ring access device 6-1 via an RAE connection transmission line 2-8, and is also connected to a TIE connection line 6-1.
4 and SWE control line 6-6 to switch device 6-
Connected to 2. Transmission line interface device 6-1
performs the following processing. (1) Terminate the ring access connection transmission line 2-8, extract cells on the reception transmission line, and transmit the extracted cells to the switch device 6-2 via the TIE connection line 6-4. (2) Terminate the TIE connection line 6-4 and send the cells on the TIE connection line to the RAE connection transmission line 2-8. (3) If a failure in RAE connection transmission line 2-8 is detected,
The reception transmission line 2-8 is looped back to the transmission transmission line 2-8.

[0033] The node interface device 6-3 is an NI
It is connected to the switching device 6-2 via the E connection line 6-5, and is also connected to the subscriber accommodation node 2-1 via the SN connection line 2-5, or to the switching center connection node 2-3 via the CN connection line 2-6. , or to the management node 2-4 via the MN connection line 2-7. The node interface device 6-3 performs the following processing. (1) SN connection line 2-5 or CN connection line 2-6
, or the MN connection line 2-7, and extract the cell. (2) SN connection line 2-5 or CN connection line 2-6
, or transmit cells to the RAE connection transmission line 2-8 transmitted by the CV path and UV path on the MN connection line 2-7 to the switch device 6 via the NIE connection line 6-5.
-2. (3) SN connection line 2-5 or CN connection line 2-6
, or the SWE control cell from the management node 2-4 transmitted by the CV path on the MN connection line 2-7,
It is transferred to the switch device 6-2 via the E control line 6-6. (4) Terminate the NIE connection line 6-5, extract the received cell from the switch device 6-2, and
or CN connection line 2-6, or MN connection line 2-7
The cell is transmitted to the subscriber accommodating node 2-1, the exchange connecting node 2-3, or the management node 2-4.

[0034] The switch device 6-2 connects the TIE connection line 6
-4 and the NIE connection line 6-5 are terminated to extract cells. The switching device 6-2 also performs cell exchange between the following paths based on control information from the management node 2-4. ■ Cells on the CV path and UV path of the TIE connection line 6-4 and the CV path and U of the NIE connection line 6-5
Cells on the V path ■ Cells on the CV and UV paths of the TIE connection line 6-4 and cells on the CV and UV paths of other TIE connection lines.
The IE connection line 6-5 and the SWE connection line 6-6 are composed of a reception line and a transmission line.

7 and 8, the switching system in this embodiment is connected to switching center A by switching center connection node (CN) #1, and connected to switching center B by switching center connection node (CN) #2. An example of a connection configuration of a virtual path with an exchange center is shown. Note that subscriber node #1 is shown here as a representative example of subscriber accommodating node 2-1. Further, FIG. 9 shows an example of a switching procedure when a virtual path set between subscriber accommodating node 2-1 and switching center A is switched to switching center B.

In FIGS. 7 and 8, between the devices in the ring access device 2-2 and between the devices in the ring access device 2-2,
The connection between the exchange center connection node 2-3 is shown by separating the connection configuration shown in FIG. 6 into a transmission line and a reception line, and is connected by the following connection lines. Between transmission line interface device 6-1 and switch device 6-2: SWE control line (
Transmission) 6-61, SWE control line (reception) 6-62TI
E connection line (transmission) 6-41, TIE connection line (reception)
6-42 Between switch device 6-2 and node interface device 6-3: NIE connection line (transmission) 6-51, NIE
Connection line (reception) 6-52 Node interface device 6
-3 Between switching center connection nodes 2 and 3: CN connection line (transmission)
2-61, CN connection line (receiving) 2-62 Furthermore, the nodes of the switching system in this embodiment and the nodes and the switching center in the switching system in this embodiment are connected by virtual paths shown below.

Management node 2-4 and ring access device #
1: RAE#1-SWE control CV path (transmission) 7-1
1. RAE#1-SWE control CV path (reception) 7-12
Between management node 2-4 and ring access device #2: RAE
#2-SWE control CV path (transmission) 7-21, RAE#
2-SWE control CV path (reception) 7-22 management node 2
-4 and exchange A: exchange A test CV path (transmission) 7-
31. Exchange A test CV path (reception) 7-32 Between management node 2-4 and exchange B: exchange B test CV path (transmission)
7-41, Exchange B test CV path (reception) 7-42 Between subscriber accommodation node #1 and exchange: CV path (transmission) 7-5
1. CV path (receiving) 7-52 UV path (transmitting) 7-6
1. UV path (receiving) 7-62 Exchange A and Exchange A
If the transmission path between the subscriber accommodating node 2-1 and the exchange is normal, the CV path and U
Connect V-path with exchange A. In addition, if the transmission path between exchange A and exchange A is abnormal, the CV path and UV path between exchange A and exchange B are changed as shown in Figure 8.
Connect to.

The switching operation of the CV path and UV path between the switching center 1-3 will be explained below with reference to FIGS. 7, 8 and 9. (1) The management node 2-4 sends a message to switching center A.
By the test CV path (transmission) 7-31, to exchange B by the exchange B test CV path (transmission) 7-41,
Sends a test signal to confirm the normality of the communication channel with the switching center. (2) The management node 2-4 sends a response signal to the test signal from the exchange A to the exchange A test CV path (reception) 7-3.
2, and a response signal to the test signal from exchange B is monitored by exchange B test CV path (reception) 7-42. (3) When the management node 2-4 normally receives the response signal from switching center A, it determines that the communication path with switching center A is normal, and the CV path with switching center A and UV The path connection is maintained, and the state of belonging to the switching center A of this switching system is continued. (4) If the management node 2-4 cannot receive the response signal from the exchange A, it determines that there is an abnormality in the exchange A or the transmission path between the exchange A and the exchange A. Then, if the response signal from exchange B is successfully received, ring access device #1-SW
E control CV path (transmission) 7-11 to ring access device #1, ring access device #2-SWE control C
Ring access device # by V-path (transmission) 7-21
2, the following cellular SWE control information is transferred to perform virtual path connection control. ■SNCV path #1 (transmission) 7-51, SNCV path #1 (reception) 7-52, SNUV set between subscriber accommodation node #1 and switching center A for ring access device #1 Path #1 (send) 7
-61 and SNUV path #1 (receiving) 7-62 are connected to the ring access device #2 side■SNCV path set between the ring access device #2 and the subscriber accommodating node #1 exchange #1 (transmission) 7-51, SNCV
Path #1 (reception) 7-52, SNUV path #1 (transmission)
7-61 and SNUV#1 path (receiving) 7-62 to the switching center B side (5) The transmission line interface device 6-1 of ring access device #1 connects the RAE connection transmission line 2 from the management node 2-4. - Ring access device #1-SWE control C via -8
The SWE control cells transferred by the V path (transmission) 7-11 are separated and sent via the SWE control line (transmission) 6-61 to the ring access device #1 to the switch by the SWE control CV path (transmission) 7-11. Transfer to device 6-2. (6) When the switching device 6-2 of the ring access device #1 receives the cellized SWE control information from the management node 2-4, it rewrites the contents of the connection setting table of the CV path and the UV path, and The CV path and UV path that were connected to switching center A via interface device 6-3 and switching center connection node #1 are connected to ring access device #2 via RAE connection transmission path 2-8. TIE connection line (receiving) 6- on the transmission line interface device 6-1 side
42. (7) When the switch device 6-2 of ring access device #1 completes the connection change between the CV path and the UV path, it converts the path setting completion indication signal into cells and sends it to the SWE control line (reception).
6-62, transmission line interface device 6-1, and R
RAE-SWE control CV via AE connection transmission line 2-8
It is transferred to the management node 2-4 via the path (reception) 7-12. (8) The transmission path interface device 6-1 of the ring access device #2 transfers data from the management node 2-4 via the RAE connection transmission path 2-8 to the RAE #2-SWE control CV path (transmission) 7-21. The transmitted SWE control cell is separated and sent to RAE# via the SWE control line (transmission) 6-61.
2-SWE control CV path (transmission) 7-21 to transfer to the switch device 6-2. (9) When the switching device 6-2 of the ring access device #2 receives the SWE control information in cells from the management node 2-4, it rewrites the contents of the connection setting table for the CV path and the UV path, and CV path and U of accommodation node #1
A V-path is set between the node interface device 6-3 and the switching center B via the switching center connection node #2. (10) Switch device 6-2 of ring access device #2
When the CV path and UV path settings are completed, the path setting completion display signal is converted into cells and sent to the SWE control line (receiving) 6.
-62, transmission line interface device 6-1, and RA
RAE#2-SWE control C via E connection transmission line 2-8
It is transferred to the management node 2-4 via the V-path (reception) 7-22. (11) Management node 2-4 is ring access device #1
and receives the path setting completion indication signal from ring access device #2, and sets the CV path and UV of subscriber accommodating node 2-1.
The path connection change from switching center A to switching center B is completed.

Although the present embodiment has been described as an example in which two exchanges 1-3 are provided, the present invention is of course not limited to this. Also, a subscriber network system 1-2, a subscriber accommodation node 2-1, a subscriber line termination device 3
-1 is designated as #1 to #n, respectively, but this indicates a plurality of numbers for convenience, and there is no particular need for these numbers to be the same.

[0040]

As described above, according to the present invention, the ISDN subscriber network system can autonomously provide switching services, and the connection relationship with a plurality of switching stations can be made variable. Provides switching services between subscribers accommodated in the ISDN subscriber network system even when the switching center or the transmission path between the switching center and the switching center fails in the case of an ISDN switching system configuration in which the switching center is connected to one switching center. be able to. In addition, in the case of an ISDN switching system configuration in which the ISDN subscriber network system is connected to two or more switching centers, even if one switching center or the transmission line between the switching centers fails, the ISDN subscriber network system can accommodate the problem. subscriber-to-subscriber switching services, and ISDN services provided by other normal exchanges.
It is possible to provide switching services via a switching center to subscribers accommodated in a subscriber network system. Additionally, ISDN
IS where the subscriber network system is connected to two or more switching centers
In the case of a DN switching system configuration, it is possible to provide a switching service in which remote nodes are connected in a distributed manner to a plurality of switching centers, and it is expected that a highly reliable ISDN switching system will be constructed.

[0041] The present invention also covers the number of remote nodes and the number of connected exchanges, the internal configuration method of the ISDN subscriber network system, the types of paths to and from the exchanges, setting/switching procedures,
Since there are no restrictions on path setting/switching locations, applicable communication networks, etc., a highly reliable ISDN switching system can be provided for various communication networks such as public communication networks and corporate communication networks.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of an ISDN switching system according to the present invention.

FIG. 2 is a configuration diagram showing an example of the configuration of the subscriber network system in FIG. 1;

FIG. 3 is a configuration diagram showing an example of the configuration of the subscriber accommodation node in FIG. 2;

FIG. 4 is a configuration diagram showing an example of the configuration of an exchange connecting node in FIG. 2;

FIG. 5 is a configuration diagram showing an example of the configuration of the management node in FIG. 2;

FIG. 6 is a configuration diagram showing an example of the configuration of the ring access device in FIG. 2;

FIG. 7 is a connection diagram showing an example of a connection configuration when exchange A is normal in this embodiment.

FIG. 8 is a connection diagram showing an example of a connection configuration when an abnormality occurs in exchange A in this embodiment.

FIG. 9 is a flow diagram showing the operation of a virtual path switching procedure with an exchange.

FIG. 10 is a configuration diagram of an ISDN switching system in the prior art.

[Explanation of symbols]

Claims (1)

[Claims] Claim 1: An ISDN subscriber network system consisting of a switch installed in a switching center and a remote node installed in a remote station accommodating remotely located subscribers, and in which a plurality of remote nodes are connected by a transmission path. An ISDN switching system comprising a plurality of remote nodes connected in a ring configuration having call processing means and communication line switching means for providing switching services to accommodated subscribers,
remote node communication line connection control means for providing exchange services between subscribers accommodated by each of the remote nodes connected in the ring configuration; an asynchronous transfer mode communication means for transferring information in a transfer mode; an asynchronous transfer mode communication means for transferring information between the remote node and a plurality of the switching stations; and detecting an abnormality in a transmission path between the switching stations. , a path switching means for switching an information transfer path to a normal exchange, and is characterized in that it is capable of providing switching services autonomously in the ISDN subscriber network system, and that connection relationships with a plurality of exchanges can be made variable. system.