JP2001298461A - Speech path automatic changeover method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speech path automatic changeover method that does not take much time for changeover into a stand-by connection and precludes the possibility of the dissipation of a speech itself. SOLUTION: An operating connection is established to form a speech path (S1), an ATM switch a1 selects a relay ATM switch c3 to establish a stand-by connection among the ATM switch a1, the ATM switch 3c, and an ATM switch d4, and the ATM switches a1, d4 respectively reserve their internal paths for the stand-by connection (S2-S4). On the occurrence of a fault between the switches forming the operating connection, when the ATM switch a1 detects the fault, the ATM switch a1 switches the internal path from the operating connection into the stand-by connection, transmits a 'release' signaling 13 to the ATM switch d4 via the ATM switch b2, and the ATM switch d4 switches the internal path from the operating connection into the stand-by connection (S5).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for automatically switching a call path, and more particularly to a method for automatically switching a call path when a failure occurs.

[0002]

2. Description of the Related Art Conventionally, this kind of automatic call path switching method is based on SPVC (semi-fixed connection:
Soft Permanent Virtual Co
When a failure occurs in the middle of an SPVC connection indicating a path connected by nection (soft permanent virtual connection): defined by the ATM Forum), the path is automatically switched from the path in which a call is being performed to another path that is bypassed. Used for

[0003] This conventional method for automatically switching the call path is as follows.
If a fault occurs on the route in the middle of the SPVC connection (operation connection) during the call from the originating terminal of the ATM switch a to the destination terminal of the ATM switch b, the route during the call is automatically performed. (Virtual Path) indicating the same virtual path identifier when switching to another route (backup connection) that bypasses the
Connection Identifier: AT
M Forum) and a VCCI (Virtual Channel Conn) indicating a virtual channel identifier.
optionIdentifier: ATM Foru
m) is set at the same time as the working connection for the backup spare connection.
Specified by TM Forum: According to this specification, a setting request of VPCI / VCCI having the same value as the value already specified is normally rejected. ), The working connection is cut, and then the V-connection for the working connection is established between the originating terminal point and the receiving-side terminal point for a spare connection for bypass.
The same VPCI / VCC as the operation connection is established by setting PCI / VCCI and establishing a spare connection.
I is used.

[0004]

The above-mentioned conventional method for automatically switching the communication path is based on the SPVC connection (operating connection) during which a call is being established by connecting the originating terminal of the ATM exchange a to the terminating end of the ATM exchange d. ), When a failure occurs in the middle of the route, when automatically switching to another route (backup connection) to bypass from the route in which a call is in progress, disconnect the operation connection and then send it out for the backup spare connection VPCI / VCCI for the operation connection is set at the end point on the receiving side and the terminating point on the receiving side, and a backup connection is established to establish the same VP as the operation connection.
Since CI / VCCI is used, it takes time to switch to the spare connection for detour. Then, this time is a predetermined time (for example, 10 sec)
If this is the case, there is a problem that the call itself may disappear.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of automatically switching a communication path in which it takes no time to switch to a spare connection and there is no danger of the call itself disappearing in order to eliminate such a conventional disadvantage.

[0006]

According to a first automatic call route switching method of the present invention, a backup connection indicating a bypass route is established in advance, and a failure occurs in an operation connection indicating a route during a call. When this is done, the operational connection is switched to the previously established backup connection.

A second automatic call path switching method according to the present invention is to provide a backup connection indicating a detour path between an originating exchange including an originating end point and a receiving end exchange including a terminating end point. When a failure has occurred in an operation connection that has been established in advance and indicates a route during a call between the originating exchange including the originating end point and the destination exchange including the terminating end point. The switching between the internal exchanges of the originating exchange and the destination exchange is switched from the operational connection to the backup connection, and the originating end point and the terminating end point are switched. I try to connect.

[0008] In the first and second methods for automatically switching between call paths according to the present invention, the connection is SPVC (semi-fixed connection: Soft Permanent V).
The connection is made by an actual connection (soft permanent virtual connection): defined by the ATM Forum.

Further, in the first and second methods for automatically switching between call paths according to the present invention, the VPCI indicating the same virtual path identifier for the working connection and the backup connection is provided.
(Virtual Path Connection
Identifier: defined by ATM Forum) and a VCCI (Virtual C) indicating a virtual channel identifier.
hannel Connection Identif
ier: defined in the ATM Forum).

In the first and second methods for automatically switching between call paths according to the present invention, after the operation connection is established and the call path is formed, the protection connection is established before the backup connection is established. SPV requesting
A field indicating that the SPVC connection request is a request for setting up a spare connection is added to the C connection request, and the SPVC connection request is transmitted from the originating exchange to the destination exchange.

The third automatic call path switching method according to the present invention is characterized in that the transmission side termination of the ATM switch a including a SPVC termination point (hereinafter referred to as a transmission side termination point) which is a termination point on the transmission side of the SPVC. From this point, the path inside the ATM switch d including the SPVC termination point on the receiving side (hereinafter referred to as the terminating side termination point) is passed through the path inside the ATM exchange a and the relaying ATM exchange b. A first step of establishing a SPVC connection indicating a path connected by the SPVC to the terminating end point through the terminal (hereinafter, the established SPVC connection is referred to as an operation connection) to form a communication path; , A
A relay ATM, which is a route other than the working connection, for connecting from the originating end point to the terminating end point as the backup connection by the TM exchange a.
Selects the exchange c, and sets the VPCI and VCCI that are identically set for the working connection at the originating end point and the called end point, and the bandwidth of the working connection with the calling end point and the called side. SPVC including termination point and instructions for setting for the backup connection
Connection request (hereinafter referred to as setup)
A signaling is transmitted from the ATM switch a to the ATM switch d via the selected ATM switch c, and a path inside the ATM switch a in a path between the originating terminal point and the ATM switch c. A second step of reserving to set the bandwidth and the VPCI / VCCI in the ATM switch c, receiving the "setup" signaling by the ATM switch c and receiving the "setup" signaling.
And a path within the ATM switch c, and transmits the "setup" signaling to the A
A third step of sending to the TM exchange d, and receiving, by the ATM exchange d, the "setup" signaling to the path inside the ATM exchange d in the path between the terminating termination point and the ATM exchange c. The band and the V
A connection establishment (hereinafter, referred to as a "connect") signal indicating that the connection has been established between the ATM exchange d and the ATM exchange c, while making a reservation so as to set PCI / the VCCI and establishing the connection between the ATM exchange d and the ATM exchange c. To the ATM switch a via the backup connection, and the ATM switch a
Receiving said "connect" signaling via said backup connection, said ATM switch a and said ATM switch d
A fourth step of establishing a backup connection between the ATM switch and the ATM switch a when the ATM switch a detects this fault when a fault occurs between the ATM switches forming the working connection. a is a call disconnection request (hereinafter referred to as release) for disconnecting a path inside the ATM exchange a in a path connecting the originating end point and the ATM exchange b and disconnecting a path for the operation connection. Signaling) to the ATM
The connection is established by setting the reserved bandwidth and the VPCI / VCCI on the path inside the ATM switch a in the path between the originating end point and the ATM switch c by transmitting to the switch b. The ATM switch b receives the "release" signaling, disconnects the connection inside the ATM switch b, transmits the "release" signaling to the ATM switch d, and the ATM switch d receives the "release" signaling. The path inside the ATM switch d in the path connecting the terminating end point and the ATM exchange b is cut off, and the ATM in the path between the terminating end point and the ATM exchange c is disconnected.
The reserved band and the VP on a route inside the exchange d.
A fifth step of establishing a connection by setting CI / the VCCI, and when the ATM switch d detects the failure, the ATM switch d connects the terminating end point to the ATM switch b. Disconnects the route inside the ATM exchange d in the route, and releases the "release"
Sending a signaling to said ATM switch b and said AT in a path between said terminating end point and said ATM switch c.
The reserved band and the V
The ATM switch b receives the "release" signaling, disconnects the connection inside the ATM switch b, and transmits the "release" signaling to the ATM switch a.
The ATM exchange a receives the "release" signaling, disconnects the path inside the ATM exchange a in the path connecting the originating end point and the ATM exchange b, and terminates the originating end. A sixth step of setting the reserved band and the VPCI / VCCI on a path inside the ATM switch a in a path between a point and the ATM switch c to establish a connection;
When the TM exchange b detects the fault, the AT switch
The M exchange b disconnects the connection inside the ATM exchange b and sends the "release" signaling to the ATM exchange a and the ATM exchange d, and the ATM exchange a receives the "release" signaling and receives the "release" signaling. A path inside the ATM switch a in the path connecting the terminal point and the ATM switch b is disconnected, and the ATM in the path between the originating terminal point and the ATM switch c is disconnected.
The reserved band and the VP on a path inside the exchange a.
CI / the VCCI is established to establish a connection, and the ATM exchange d receives the "release" signaling, and the ATM exchange d in the path connecting the terminating end point and the ATM exchange b. A connection is established by cutting the internal path and setting the reserved band and the VPCI / VCCI on the path inside the ATM switch d in the path between the terminating end point and the ATM switch c. 7) a seventh step.

Further, in the third method for automatically switching a call path according to the present invention, in the second step, a field indicating that the "setup" signaling is for setting up a spare connection is added to the "setup" signaling. The data is transmitted to the ATM exchange d.

[0013]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 is a block diagram showing an example of an exchange network used in the embodiment of the present invention.

This exchange network is, for example, an AT
It comprises an M exchange a1, an ATM exchange b2, an ATM exchange c3 and an ATM exchange d4, and the exchanges are connected by a physical connection. ATM exchange a1
Is a switch a for connecting the line aa, the line ab, the line ac and the line, and a control unit a for controlling the ATM exchange a1.
5, the ATM exchange b2 is composed of a line ba and a line bb, a switch b for connecting the lines and a control unit b6 for controlling the ATM exchange b2, and the ATM exchange c3 is composed of a line ca and a line cb. A control unit c7 for controlling a switch c for connecting lines and an ATM exchange c3.
The ATM exchange d4 has a line da and a line d.
b and the switches d and A connecting the line dc and this line
The control unit d8 controls the TM exchange d4.

FIG. 3 shows an SPVC (semi-fixed connection: Soft Permanent Vir).
dual connection (soft permanent virtual connection): SPVC termination point (hereinafter referred to as transmission-side termination point 9) which is the termination point on the originating side of the ATM Forum (defined by the ATM Forum) (the opposite side of the switch a of the line aa of the ATM exchange a1). ) From the originating end point 9 of the ATM exchange a1 through the internal route (line aa, switch a and line ab) of the ATM exchange a1.
Via the TM exchange b2 (line ba, switch b and line bb), a path (line da, switch) inside the ATM exchange d4 including the SPVC termination point on the receiving side (hereinafter referred to as the terminating end point 10). d and the line dc), an SPVC connection indicating a path connected by the SPVC is established to the terminating end point 10 (the opposite side of the switch d of the line dc of the ATM exchange d4) (hereinafter, the established SPVC connection). Is referred to as an operation connection.) This shows a state in which a communication path is formed.

FIG. 1 and FIG. 2 are flow charts showing one embodiment of the method for automatically switching a call path according to the present invention.

The embodiment shown in FIG. 1 and FIG.
As shown in the figure, a relay ATM passes from the originating end point 9 of the ATM exchange a1 through a path inside the ATM exchange a1.
A first step (S1) of establishing a SPVC connection to a terminating end point 10 through a path inside the ATM switch d4 via the switch b2 to form a communication path;
A relay ATM switch c3, which is a route other than the operation connection, is used by the TM switch a1 to connect the originating end point 9 to the destination end point 10 as a spare connection indicating a route for switching and bypassing the call route. Is selected, and the VPCI and VCCI that are set for the operation connection in the same way at the originating end point 9 and the terminating end point 10 and the band of the operation connection (the band indicates a unit of information that can be transmitted per second). ), And an SPVC connection request (hereinafter, referred to as setup) signaling including an instruction for setting a traffic attribute including a backup connection to the originating end point 9 and the receiving end point 10 for a backup connection from the ATM switch a1. The call is transmitted to the ATM exchange d4 via the selected ATM exchange c3, and the originating end point 9 and the ATM are exchanged. ATM switch a1 internal path in the path between the 換機 c3 (line aa, switches a and line a
In c), a reservation is made to set the band and VPCI / VCCI included in the “setup” signaling 11 (reservation indicates preparation for setting the band and VPCI / VCCI to establish a connection). In the second step (S2), the ATM switch c3 receives the "setup" signaling 11 and establishes a connection with the ATM switch a1 and a path (line ca, switch c and line cb) inside the ATM switch c3. The third step (S3) of sending the "setup" signaling 11 to the ATM exchange d4, and receiving the "setup" signaling 11 by the ATM exchange d4, and setting the path between the terminating end point 10 and the ATM exchange c3. ATM
A reservation is made to set the bandwidth included in the "setup" signaling 11 and VPCI / VCCI on the path (line db, switch d and line dc) inside the exchange d4, and the connection between the ATM exchange d4 and the ATM exchange c3. Is established, and a connection establishment (hereinafter, referred to as "connect") signal indicating that the connection has been established is transmitted to the ATM switch a1 via the backup connection (ATM switch c3), and the "connect" signaling 12 is transmitted by the ATM switch a1. A fourth step (S) of receiving via the protection connection and establishing a protection connection between the ATM switch a1 and the ATM switch d4.
4) and when a failure occurs between the ATM exchanges forming the operation connection, and when the ATM exchange a1 detects this failure, the ATM exchange a1 connects the originating end point 9 to the ATM exchange b2. ATM on the route
A call disconnection request (hereinafter, referred to as release) that disconnects a path inside the exchange a1 (disconnection indicates disconnection of a logical connection) and requests disconnection of a path of an operation connection.
The signaling is transmitted to the ATM switch b2 on the route of the operation connection, and the bandwidth and VPCI / VCCI reserved on the path inside the ATM switch a1 in the path between the originating terminal 9 and the ATM switch c3 are set to establish the connection. Established and the ATM switch b2 has "release" signaling 13
In response to this, the connection inside the ATM exchange b2 is disconnected and this "release" signaling is transmitted to the ATM exchange d4 via the operation connection path, and the ATM exchange d4
Is the AT in the path connecting the terminating end point 10 and the ATM switch b2 in response to the "release" signaling 13.
The route inside the M exchange d4 is disconnected, and the terminating end point 10 and A
A fifth step (S5) of setting a bandwidth reserved on the path inside the ATM switch d4 in the path between the TM switch c3 and the VPCI / VCCI to establish a connection;
When a failure occurs between the ATM exchanges forming the operation connection and the ATM exchange d4 detects the failure, the ATM exchange d4 is connected to the terminating end point 10 and the ATM.
ATM switch d4 in the path connecting switch b2
The internal path is disconnected and the "release" signaling 13 is transmitted to the ATM switch b2 on the path of the operation connection, and the AT in the path between the terminating end point 10 and the ATM switch c3 is transmitted.
Bandwidth and VPCI / V reserved for the route inside the M exchange d4
The ATM switch b2 receives the "release" signaling 13 and establishes a connection with the CCI.
The connection inside the M exchange b2 is disconnected and this "release" signaling is transmitted to the ATM exchange a1 via the route of the operational connection, and the ATM exchange a1 receives the "release" signaling 13 and connects the originating end point 9 and the ATM exchange b2. The route inside the ATM exchange a1 in the connected route is cut off, and the bandwidth and VPCI / VCCI reserved for the route inside the ATM exchange a1 in the route between the originating end point 9 and the ATM exchange c3 are set. The sixth step (S6) of establishing a connection by means of an ATM switch when a failure occurs between the ATM exchanges forming the working connection.
When the M exchange b2 detects a failure, the ATM exchange b2 disconnects the connection inside the ATM exchange b2 and transmits a "release" signaling 13 to the ATM exchange a1 and the ATM exchange d4 on the path of the operation connection. Is "release" signaling 13
Then, the path inside the ATM exchange a1 in the path connecting the originating end point 9 and the ATM exchange b2 is disconnected, and the AT in the path between the originating end point 9 and the ATM exchange c3 is disconnected.
Bandwidth and VPCI / V reserved for the route inside the M exchange a1
After setting the CCI and establishing a connection, the ATM switch d4 receives the "release" signaling 13 and disconnects the path inside the ATM switch d4 in the path connecting the terminating end point 10 and the ATM switch b2. Terminating end point 1
ATM switch d in the path between 0 and ATM switch c3
(7) A seventh step of setting a bandwidth reserved for an internal path and VPCI / VCCI to establish a connection (S
7).

Next, the operation of the automatic call route switching method according to the present embodiment will be described with reference to FIGS. 3, 4, 5, 6, 7, and 8.
This will be described in detail with reference to FIG.

FIG. 4 is a block diagram showing an example when establishing a backup connection between exchanges.

FIG. 5 shows an ATM switch a and an ATM switch b.
FIG. 10 is a block diagram showing an example of switching from the working connection to the standby connection when a failure occurs between the ATM switch a and the failure detected.

FIG. 6 shows an ATM switch b and an ATM switch d.
FIG. 10 is a block diagram showing an example of switching from the working connection to the backup connection when a failure occurs between the ATM switch d and the ATM switch d.

FIG. 7 shows an ATM switch a and an ATM switch b.
FIG. 13 is a block diagram showing an example of switching from the working connection to the backup connection when a failure occurs between the ATM switch b and the failure, and FIG.

FIG. 8 shows an ATM switch b and an ATM switch d.
FIG. 13 is a block diagram showing an example of switching from the working connection to the backup connection when a failure occurs between the ATM switch b and the failure, and FIG.

In FIG. 1, when the network provider receives a request from a user who wants to use this network, at the time of initialization, which is the work of establishing a connection between the originating end point 9 and the terminating end point 10, Conventional SPVC
The operation connection is set by the setting method as shown in FIG. That is, according to the instructions of the network provider,
The control unit a5 of the ATM switch a1 has a traffic attribute including a band according to the user's contract and a VPCI / VCC.
I is set as the originating end point 9, and the ATM switch b2, which is the optimum route in the network, is relayed from the routing information (network information) prepared in advance.
A "setup" signaling 11 including an instruction for setting a traffic attribute including a band according to a user contract and VPCI / VCCI to the terminating end point 10 by selecting the switch as an exchange and relaying the ATM exchange b2 to A
This is transmitted to the control unit d8 of the TM exchange d4. At this time, the control section a5 of the ATM switch a1 and the AT are sent in addition to the "setup" signaling 11 by adding a field indicating that the "setup" signaling 11 is for setting an operation connection with a backup connection.
This is notified to the control unit d8 of the M exchange d4 (S1).

Then, as shown in FIG. 4, the control unit a5 of the ATM exchange a1 connects the originating end point 9 to the terminating end point 10 as a backup connection, which is a route other than the working connection. Of the ATM switch c3, the VPCI indicating the virtual path identifier, the VCCI indicating the virtual channel identifier, and the VCCI indicating the virtual channel identifier, which are the same for the originating end point 9 and the terminating end point 10, for the working connection. A "setup" signaling 11 including an instruction for setting the traffic attribute including the traffic attribute to the originating end point 9 and the terminating end point 10 for the backup connection is sent to the line ac of the ATM switch a1.
Via the selected relay ATM switch c3 (line ca, switch c and line cb), and sends it to the terminating end point 10 of the ATM switch d4 (at this time, a special Field (for example, NCCI (Network Call)
Correlation Identifier: AT
M Forum)), and informs the control unit d8 of the ATM switch d4 on the receiving side that the "setup" signaling 11 is for setting a detour. As a result, the normal SPVC is provided to the control units on both the calling side and the called side.
Rather, it is made to recognize that it is a detour SPVC, and only when the working connection and the backup connection are the same VPCI / VCCI designation at the SPVC termination point on both the receiving side and the transmitting side, it is a detour SPVC. Each control is
Setup “signaling 11” is received. In a normal case where there is no special field (for example, NCCI), VPCI / VCC having the same value as the value already specified is used.
If I is set, "requested VPCI /
VCCInot available "and" setup "signaling 11 is rejected.), The AT in the path between the originating end point 9 and the relay ATM exchange c3.
A reservation is made to set the bandwidth and VPCI / VCCI included in the "setup" signaling 11 on the paths (line aa, switch a and line ac) inside the M exchange a1 (S2), and the control unit c7 of the ATM exchange c3 makes a reservation. , FIG.
As shown in the figure, the "setup" signaling 11 is received via the line ca, and the lines ac and A of the ATM switch a1 are received.
The connection between the lines ca of the TM exchange c3 is established, and the path (the line ca, the switch c and the line cb) inside the ATM exchange c3 is established, and this "setup" signaling 11 is sent to the ATM exchange d4 via the line cb ( S3), by the control unit d8 of the ATM exchange d4,
As shown in FIG.
Is received via the line db, and the terminating end point 10 and the relay A
In the path (line db, switch d and line dc) inside the ATM switch d4 in the path to the TM switch c3, the band included in the "setup" signaling 11 and the VPCI
/ VCCI and ATM
A connection between the line db of the exchange d4 and the line cb of the ATM exchange c3 is established, and a "connect" signaling 12 indicating that the connection has been established is transmitted via the backup connection (the line db, the ATM exchange c3) to the ATM exchange a.
1 and the ATM switch a1 receives the "connect" signaling 12 via the backup connection and the ATM switch a1.
A spare connection is established between the exchange a1 and the ATM exchange d4 (S4).

In FIG. 2, when a fault occurs between the ATM switch a1 and the ATM switch b2 forming the working connection and this fault is detected on the line ab of the ATM switch a1, as shown in FIG. When the control unit a5 of the ATM exchange a1 determines that this operation connection is an operation connection having a backup connection notified in step 1 (S1), the originating terminal 9 and the relay AT
ATM switch a in the path connecting M switch b2
1 to release the "release" signaling 13 requesting the disconnection of the internal path and the disconnection of the operation connection path via the ATM connection b2 on the operation connection path (line ab, line ba).
And the bandwidth reserved for the path inside the ATM switch a1 in the path between the originating end point 9 and the ATM switch c3 and V
Set up PCI / VCCI to establish a connection,
The ATM switch b2 receives the "release" signaling 13 and disconnects the path inside the ATM switch b2 in the path connecting the ATM switch a1 and the ATM switch d4.
Release "signaling 13" is transmitted to the ATM switch d4 through the route (line bb, line da) of the operation connection,
The ATM exchange d4 receives the "release" signaling 13, disconnects the path inside the ATM exchange d4 in the path connecting the terminating end point 10 and the relay ATM exchange b2, and terminates the terminating end point 10 and the relay ATM. "Release complete" signaling indicating that the connection is established by setting the reserved bandwidth and VPCI / VCCI on the path inside the ATM switch d4 in the path between the switch c3 and the path of the working connection, and Is sent to the ATM exchange a1 via the operation connection (S5).

ATM for forming an operation connection
A failure occurs between the exchange b2 and the ATM exchange d4,
When this failure is detected on the line da of the ATM exchange d4, the control unit d8 of the ATM exchange d4 as shown in FIG.
Thus, when this operation connection is an operation connection having a backup connection notified in step 1 (S1), the inside of the ATM switch d4 in the path connecting the terminating end point 10 and the relay ATM switch b2 is connected. The route is disconnected and the "release" signaling 13 is transmitted to the ATM switch b2 via the route (line da, line bb) of the working connection, and the route inside the ATM switch d4 in the route between the terminating end point 10 and the ATM switch c3. Bandwidth and V reserved
Set up PCI / VCCI to establish a connection,
The ATM switch b2 receives the "release" signaling 13 and disconnects the path inside the ATM switch b2 in the path connecting the ATM switch a1 and the ATM switch d4.
Release "signaling 13" is transmitted to the ATM switch a1 through the route (line ba, line ab) of the operation connection,
Upon receiving the "release" signaling 13, the ATM switch a1 disconnects the path inside the ATM switch a1 in the path connecting the originating end point 9 and the relay ATM exchange b2, and disconnects the originating end point 9 and the relay ATM. Bandwidth and VP reserved for the path inside the ATM switch a1 in the path to the switch c3
Set up CI / VCCI to establish a connection,
The "release complete" signaling is sent to the ATM switch d4 via the working connection (S6).

Further, an ATM for forming an operation connection
A failure occurs between the exchange a1 and the ATM exchange b2 or between the ATM exchange b2 and the ATM exchange d4,
When the line ba or the line bb of the exchange b2 detects a failure, the control unit b6 of the ATM exchange b2 controls the ATM exchange a1 and the ATM exchange d as shown in FIG. 7 or FIG.
4 and disconnects the path inside the ATM switch b2 in the path connected to the ATM switch b2, transmits "release" signaling 13 to the ATM switch a1 and the ATM switch d4 via the path of the operation connection, and the control unit a5 of the ATM switch a1 In response to the "release" signaling 13, when the operation connection is an operation connection with a backup connection notified in step 1 (S1), the originating end point 9 is connected to the relay ATM switch b2. The route inside the ATM switch a1 in the route is disconnected, and the originating end point 9 and the relay A
A connection is established by setting a reserved bandwidth and VPCI / VCCI on the path inside the ATM switch a1 in the path between the TM switch c3 and the "release complete" signaling to the ATM switch d4 via the working connection. The control unit d8 of the ATM exchange d4 receives the "release" signaling 13 and, when this operation connection is an operation connection with a backup connection notified in step 1 (S1), relays with the terminating end point 10 A
The path inside the ATM switch d4 in the path connecting the TM switch b2 is disconnected, and the terminating end point 10 and the relay AT
The bandwidth and VPCI / VCCI reserved on the path inside the ATM switch d4 in the path between the M switch c3 and the VPCI / VCCI are set to establish a connection, and the "release complete" signaling is sent to the ATM switch a1 via the working connection. Send (S7).

In the above description, the number of relay ATM exchanges is two, and the ATM exchange b2 is switched to the ATM exchange c3. However, the number of ATM exchanges is not limited to two or more, for example, the ATM exchange b2 to the ATM exchange n ( n indicates a plurality of two or more). In addition, the ATM switch a11 transmits the AT through one relay ATM switch.
Although connected to the M exchange d4, a plurality of relay ATM exchanges may be provided if a spare connection is set by a route other than the working connection.

[0031]

As described above, according to the automatic call route switching method of the present invention, a backup connection indicating a bypass route is established in advance, and a failure occurs in an operation connection indicating a route during a call. When this occurs, the working connection is switched to the pre-established backup connection, so that it does not take much time to switch to the backup connection, and there is no danger that the call itself will disappear.

[Brief description of the drawings]

FIG. 1 is a flowchart (1) showing one embodiment of a method for automatically switching a call path according to the present invention.

FIG. 2 is a flowchart (2) showing one embodiment of the automatic call path switching method of the present invention.

FIG. 3 is a block diagram showing an example of an exchange network used in the embodiment of the present invention.

FIG. 4 is a block diagram showing an example when establishing a backup connection between exchanges.

FIG. 5 is a block diagram showing an example of switching from an active connection to a standby connection when a failure occurs between the ATM exchange a and the ATM exchange b and the ATM exchange a detects the failure.

FIG. 6 is a block diagram showing an example of switching from the working connection to the standby connection when a failure occurs between the ATM exchange b and the ATM exchange d and the ATM exchange d detects the failure.

FIG. 7 is a block diagram showing an example of switching from the working connection to the standby connection when a failure occurs between the ATM exchange a and the ATM exchange b and the ATM exchange b detects the failure.

FIG. 8 is a block diagram showing an example of switching from the working connection to the standby connection when a failure occurs between the ATM exchange b and the ATM exchange d and the ATM exchange b detects the failure.

[Explanation of symbols]

 Reference Signs List 1 ATM exchange a 2 ATM exchange b 3 ATM exchange c 4 ATM exchange d 5 control unit a 6 control unit b 7 control unit c 8 control unit d 9 originating end point 10 terminating end point 11 "setup" signaling 12 "connect “Signaling 13” “Release” signaling

Claims (7)

[Claims] 1. A spare connection indicating a detour path is established in advance, and when a failure occurs in an operation connection indicating a route during which a call is being performed, the operation connection is established with the previously established spare connection. An automatic call path switching method characterized by switching. 2. A spare connection indicating a detour path between an originating exchange including an originating end point and a terminating exchange including a terminating end point is established in advance, and the originating end is terminated. When a failure occurs in an operation connection indicating a route during a call between the originating exchange including a point and the terminating exchange including the termination point of the terminating side, the originating exchange and the terminating exchange Wherein the internal route of each of the exchanges is switched from the operation connection to the backup connection to connect the terminating point on the calling side and the terminating point on the called side. Automatic route switching method. 3. The connection according to claim 1, wherein the connection is an SPVC (semi-fixed connection: Soft Permanent Vi).
3. The method according to claim 1, wherein the connection is established by a real connection (soft permanent virtual connection): defined by ATM Forum. 4. A VPCI (Vi) indicating the same virtual path identifier for the working connection and the backup connection.
true Path Connection Ide
ntifier: defined by the ATM Forum) and a VCCI (Virtual Ch) indicating a virtual channel identifier.
inner ConnectionIdentifier
4. The automatic call path switching method according to claim 3, wherein r: defined by the ATM Forum. 5. An SPVC connection request for requesting the establishment of the backup connection after the operation connection is established and the communication path is formed and before the backup connection is established. 5. The automatic call path switching method according to claim 4, wherein said SPVC connection request is transmitted from said originating exchange to said destination exchange by adding a field indicating a request. 6. An SPV that is a termination point of an originating SPVC.
A including a C termination point (hereinafter, referred to as a transmission side termination point)
It includes the SPVC termination point on the receiving side (hereinafter, referred to as the terminating end point) from the originating end point of the TM exchange a through a path inside the ATM exchange a and the relaying ATM exchange b. An SPVC connection indicating a path connected by the SPVC is established at the terminating end point through a path inside the ATM exchange d (hereinafter, the established SPVC connection is referred to as an operation connection). A first step of forming a relay ATM switch c, which is a route other than the working connection, in order to connect the source end point to the destination end point as the standby connection by the ATM switch a. VPCI that is selected and set for the operation connection at the originating end point and the terminating end point And an instruction for setting VCCI and the bandwidth of the operational connection to the originating end point and the terminating end point for the backup connection.
A PVC connection request (hereinafter, referred to as setup) signaling is sent from the ATM switch a via the selected ATM switch c to the ATM switch d.
A second step of making a reservation so as to set the band and the VPCI / the VCCI on a path inside the ATM switch a in a path between the originating end point and the ATM switch c; In response to the "setup" signaling, the ATM exchange c establishes a connection with the ATM exchange a and a path inside the ATM exchange c.
A third step of sending a "setup" signaling to said ATM switch d; said ATM switch in a path between said terminating termination point and said ATM switch c in response to said "setup" signaling by said ATM switch d. d. A reservation is made to set the band and the VPCI / VCCI on the path inside d, and a connection is established between the ATM exchange d and the ATM exchange c to indicate that the connection has been established ( Hereinafter, it is referred to as connect.) The signaling is transmitted to the ATM switch a via the backup connection, and the "connect" signaling is received by the ATM switch a via the backup connection, and the ATM switch a and the AT are transmitted.
4th for establishing a spare connection with the M exchange d
And if a failure occurs between the ATM exchanges forming the working connection, and the ATM exchange a detects this failure, the ATM exchange a is connected to the originating end point and the ATM exchange b. And transmits a call disconnection request (hereinafter referred to as release) signaling requesting disconnection of the path inside the ATM exchange a in the path connected to the ATM exchange a to the ATM exchange b. The reserved band and the VPCI / VCCI are set on a path inside the ATM switch a in a path between the originating end point and the ATM switch c to establish a connection, and the ATM switch b Is the above
Upon receiving the "release" signaling, the connection inside the ATM exchange b is disconnected and the "release" signaling is transmitted to the ATM exchange d. The ATM exchange d receives the "release" signaling and receives the termination point and the ATM. The route inside the ATM exchange d in the route connecting the exchange b is cut off, and the route reserved in the ATM exchange d in the route between the terminating end point and the ATM exchange c is used. Bandwidth and the VPCI /
Fifth step of establishing a connection by setting the VCCI
And when the ATM exchange d detects the failure, the ATM exchange d disconnects the path inside the ATM exchange d in the path connecting the terminating end point and the ATM exchange b. The "release" signaling to the A
The reserved band and the VPCI / VCCI are transmitted to a path inside the ATM switch d in a path between the terminating end point and the ATM switch c for transmission to the TM switch b.
The ATM switch b receives the "release" signaling, disconnects the connection inside the ATM switch b, transmits the "release" signaling to the ATM switch a, and sets the ATM switch "b".
The exchange a receives the "release" signaling, disconnects the path inside the ATM exchange a in the path connecting the originating end point and the ATM exchange b, and disconnects the originating end point and the ATM exchange c. Said A in the path between
A sixth step of establishing the connection by setting the reserved band and the VPCI / VCCI on a path inside the TM exchange a, and when the ATM exchange b detects the failure, the ATM exchange b The connection inside the ATM switch b is disconnected, and the "release" signaling is transmitted to the AT switch.
M exchange a and the ATM exchange d.
In response to the "release" signaling, the M exchange a disconnects the path inside the ATM exchange a in the path connecting the originating end point and the ATM exchange b, and connects the originating end point and the ATM exchange. c, setting the reserved band and the VPCI / VCCI on a path inside the ATM switch a in a path between the ATM switch a and the connection, and establishing a connection. The ATM switch d receives the "release" signaling and The terminating end point and the ATM switch b
Disconnecting the path inside the ATM exchange d in the path connecting the ATM switch d and the reserved band to the path inside the ATM exchange d in the path between the terminating end point and the ATM exchange c. A seventh step of setting the VPCI / the VCCI to establish a connection). 7. The method according to claim 2, wherein in the second step, a field indicating that the "setup" signaling is for setting up a spare connection is added to the "setup" signaling, and the "setup" signaling is transmitted to the ATM exchange d. 7. The automatic call path switching method according to claim 6, wherein