JP2000244511A - Atm exchange system and path switching/switching-back method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimally distribute various kinds of resources in a network by making it possible to switch back to the most efficient operation form planned before generation of a fault while keeping a quality, when the fault in the network is restored. SOLUTION: A bypass path 15 is set to call-income to an ATM exchange (an ATM exchange on a call-incoming side, a finish point SW) 12 by way of an ATM exchange (bypass repeating ATM exchange, a bypass repeating point SW) 13 through the use of a signaling means automatically called based on an instruction of 'call-incoming to the ATM exchange 12 by way of the ATM exchange 13' of a routing result guided by using an optimum routing selecting function by an ATM exchange (an ATM exchange on an originating side, a start point SW) 10 receiving an after-mentioned cutting-off request when the cutting-off request of an active path 14 toward an ATM exchange 10 from an ATM exchange (a repeating ATM exchange, a repeating point SW) 11 is sent because of a fault generated between the ATM exchange 11 and the ATM exchange 12 within the network.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a PNNI (Pri).
Vate Network to Network I
ATM (asynchronous transfer) having a routing function in the Internet
(Mode: Asynchronous Transfer Mode) In connection with the switching technology, in particular, the user path on the most efficient route as a network before the occurrence of a failure is guaranteed to achieve the most efficient operation of the network and the reduction of the total network cost.
The present invention relates to a TM switching system and a path switching / returning method.

[0002]

2. Description of the Related Art Conventionally, P
NNI (Private Network to Ne)
The routing function in the network interface minimizes the maintenance intervention of the network, and the change of various elements (for example, the ATM switch, the subscriber, etc.) forming the network is exchanged between the ATM switches to optimize the network. This function automatically generates routing information. Soft-PV proposed in such a routing function in PNNI
The C (fixed virtual channel) function is an excellent function that makes full use of the routing function provided in the PNNI even when a path is set by a maintenance person and does not require a maintenance person's routing plan. The Soft-PVC function is a function that, when a network failure occurs, an ATM switch automatically makes a call on behalf of a maintenance person and sets an alternative path, conceals the network failure from an end user, and does not recognize quality deterioration. . As such a conventional technique, for example, there is a technique described in JP-A-10-190686. That is, the prior art is an ATM network which performs route calculation based on topology information exchanged with nodes, and which sets an ordinary working route and sets a backup route for recovering a failure of the working route. In the working backup path setting method in the above, each of the nodes has a path calculation means for performing a path calculation based on mutually exchanged topology information, and a connection setting signaling message exchanged between the nodes for path setting. A unique connection pair identifier in the ATM network capable of determining that the set working path and the protection path are a pair, and working / protection information indicating either working / protection, The connection pair identifier and the current / active
The working path and the protection path are set by a connection setting signaling message having protection information, and the correspondence between the working path and the protection path is grasped. As a result, the time required to switch to the spare route due to the failure of the current working route during operation can be shortened, and even if the alternative route re-calculates another alternative route due to a failure, the scale of calculation or information processing is reduced and processing is performed. It is disclosed that time can be reduced.

[0003]

However, the conventional Soft-PVC function merely sets a detour path each time a failure is encountered in order to guarantee the quality of the user path. There was a problem that it was impossible to return the user path to the route that was set as the most efficient network as before the failure occurred. The present invention has been made in view of such a problem, and an object of the present invention is to guarantee a user path on the most efficient route as a network before the occurrence of a failure and to achieve the most efficient operation and operation of the network. An object of the present invention is to provide an ATM switching system and a path switching / switchback method for reducing the total network cost.

[0004]

The gist of the first aspect of the present invention is to guarantee a user path on the most efficient path as a network before the occurrence of a failure, thereby ensuring the most efficient operation and total operation of the network. An ATM switching system that reduces the network cost of a network by performing a routing function in the PNNI to minimize the maintenance intervention of the network and to exchange various elements forming the network with each other by exchanging the ATM exchanges with each other as a network. PNNI that automatically generates optimal routing information
Means for performing a routing function, and a PVC for performing an automatic call on behalf of a maintenance person when a PNNI routing function is performed to set an alternative path and conceal the network failure from an end user.
Means for executing a function, and a user path selected and set as an optimal path as a network using the PVC function of the PNNI after being once detoured to another path due to a network failure such as a line failure. Means for executing a PNNI optimal routing selection function for switching a user path to an optimal path as a network selected before the failure recovery, in the ATM switching system. The gist of the second aspect of the present invention is to provide an ATM which guarantees a user path on the most efficient route as a network before the occurrence of a failure to achieve the most efficient operation of the network and a reduction in total network cost. An exchange system,
Performs a PNNI routing function to execute a routing function in the PNNI and to automatically generate optimal routing information as a network by causing ATM exchanges to communicate changes in various elements forming the network by minimizing network maintenance intervention. Means for executing the PNNI routing function to automatically place a call for a network failure on behalf of a maintenance person to set an alternative path and hide a network failure from an end user when performing the PNNI routing function. Means and a user path that has been selected and set as an optimal path as a network using the PVC function of the PNNI and is once detoured to another path due to a network failure such as a line failure. Selected before the disaster recovery ATM, characterized in that it comprises a means for performing the PNNI optimal routing selection function to an optimum route as a network switching back the user path
Exist in the switching system. The gist of claim 3 of the present invention resides in that the ATM exchange is configured to execute the PV of the PNNI.
A switching control means having a C function, said switching control means being capable of being activated by a maintenance person of the ATM exchange, transmitting port / virtual path information on the transmitting side, an address on the receiving side and said virtual path information. Side ATM exchange, and
After executing the optimum routing selection function of the NNI, the automatic transmission is executed from the originating ATM exchange, and a user path to the destination ATM exchange is set using a predetermined signaling procedure. The ATM switch according to claim 1 or 2, wherein: The gist of claim 4 of the present invention is:
The switching control means of the originating ATM switch, when the communication between users is interrupted mainly due to a network failure including a line failure, temporarily disconnects the user path and automatically instructs the maintenance person. 4. A PVC automatic switching function for selecting an optimal routing path as a network at the time of disconnection of the user path and restoring the user path using the same procedure as in the case where the user path is disconnected. In the ATM switching system. Further, the gist of claim 5 of the present invention is that, when the network is restored to the state before the failure, the switching control means sets the user path set by the PVC function of the PNNI before the failure occurs. 5. The ATM according to claim 2, wherein the ATM has a function of automatically or manually switching back to an optimum routing.
Exist in the switching system. The gist of claim 6 of the present invention is that the exchange control means has a working path route information holding function of storing working path information as accumulated information of an optimum route for executing switchback. An ATM switching system according to any one of claims 2 to 5, characterized in that: The gist of claim 7 of the present invention is to provide a path for ensuring the most efficient operation of the network and reducing the total network cost by guaranteeing the user path on the most efficient path as the network before the occurrence of the failure. A switching and switching back method, wherein a routing process in a PNNI is executed to minimize the maintenance intervention of a network, and changes of various elements forming a network are exchanged between ATM exchanges so that optimal routing information as a network is obtained. Automatically generated PNN
An I-routing step; a PVC step of automatically calling for a network failure in place of a maintenance person to set an alternative path to hide a network failure from an end user when performing the PNNI routing step; When a user path selected and set as an optimal path as a network by using the PVC process is once detoured to another path due to a network fault such as a line fault, the fault is recovered before the fault recovery. A PNNI optimal routing selection step of switching a user path to an optimal path as a selected network. The gist of claim 8 of the present invention is to provide a path for ensuring the most efficient operation of the network and reducing the total network cost by guaranteeing the user path on the most efficient path as the network before the occurrence of the failure. A switching and switching back method, wherein a routing process in a PNNI is executed to minimize the maintenance intervention of a network, and changes of various elements forming a network are exchanged between ATM exchanges so that optimal routing information as a network is obtained. Automatically executing a PNNI routing step for automatically generating a substitute path for a network failure on behalf of a maintenance person when performing the PNNI routing step, setting an alternative path, and hiding the network failure from an end user. Flooding
The process and the user path that has been selected and set as the optimal route as a network using the PNNI PVC process is once detoured to another route due to a network fault such as a line fault, and then restored when the fault is recovered. And a PNNI optimum routing selection step of switching a user path to an optimal path as a network selected before recovery from the failure. The gist of claim 9 of the present invention is:
A switching control step including the PVC step of the PNNI, wherein the switching control step can be started by a maintenance person of the ATM switch, and includes port / virtual path information on the transmission side;
Sends the address of the called party and the virtual path information to the sending ATM
Instructing the exchange to execute the PNNI optimal routing selection step, then executing automatic origination from the originating ATM exchange and setting a user path to the destination ATM exchange using a predetermined signaling procedure. The path switching / switching-back method according to claim 7 or 8, wherein The gist of claim 10 of the present invention resides in that the switching control step of the originating side ATM switch is configured such that when communication between users is interrupted mainly due to a network failure including a line failure in a user path, the switching is temporarily performed. Automatic PVC switching process of selecting the optimal routing path as a network at the time of disconnection of the user path and restoring the user path by using the same procedure as that when the user path is disconnected and automatically instructed by the maintenance person. 10. The path switching / switchback method according to claim 9, wherein The gist of claim 11 of the present invention is that the exchange control step comprises:
When the network is restored to the state before the failure, the PN
11. The method according to claim 8, further comprising a step of automatically or manually switching back the user path set by the PVC process of the NI to an optimum routing before a failure occurs. It is in the path switching / switchback method described. The gist of claim 12 of the present invention is that the switching control step includes a working path route information holding step of storing working path information as accumulated information of an optimum route for performing switchback. A path switching / switching-back method according to any one of claims 8 to 11, characterized in that:

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The features of each embodiment described below are as follows.
At the time of recovery from a failure after a user path that has been selected and set as an optimal path as a network by using the PNNI Soft-PVC function in an ATM switch and is once detoured to another path due to a network failure such as a line failure, The point is that the user path is switched back to the optimal route as the network selected before the failure recovery. The ATM exchange has an exchange control unit having a PNNI Soft-PVC function. That is, the exchange control means
It is started by the maintenance person of the M exchange, instructs the originating port / virtual path information, the destination address and the virtual path information to the originating ATM exchange, and executes the optimal routing selection of the PNNI. It has a Soft-PVC function to make a call and to set up a user path to the terminating ATM exchange using a normal signaling procedure. As a result, the total network cost can be reduced by guaranteeing the user path on the most efficient route as the network before the occurrence of the failure. In the future, if the processor that controls the processing capacity of software is further accelerated and switching / switchback of all user paths can be performed in a short time, a hardware redundant configuration as a measure against network failure will be adopted. It has the potential to be used as a substitute, in other words, it can be used as a means for implementing a network redundancy configuration at low cost. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First Embodiment) FIG. 1 shows an embodiment A of the present invention.
FIG. 3 is an operation principle diagram of a TM switching system and a path switching / returning method. ATM switch (Receiving side ATM switch,
The end point SW) 12 and the ATM exchange 13 (the detour relay ATM exchange and the detour relay point SW) are provided with a PNNI function, Soft-
It has a PVC function, a signaling function, and the like.

In the Soft-PVC function, in response to a network failure, an ATM switch automatically sets a substitute path by making an automatic call on behalf of a maintenance person, hides the network failure from an end user, and does not consider quality deterioration. Function.

The working path 14 is connected to an ATM switch (originating AT) by a maintenance person's instruction before a failure occurs in the network.
M exchange (starting point SW) 10 using the optimal routing selection function of the ATM switch (originating ATM switch, starting point S)
W) ATM switching (reception ATM switching, termination point S) via an ATM exchange (transit ATM exchange, relay point SW) 11 using a signaling procedure automatically originated from 10
W) This is a path set for arriving at 12.

[0009] The bypass path 15 is an ATM in the network.
Exchange (relay ATM exchange, relay point SW) 11 and AT
The working path 14 from the ATM exchange (transit ATM exchange, relay point SW) 11 to the ATM exchange (originating ATM exchange, start point SW) 10 due to a failure occurring between the M exchanges (reception-side ATM exchange, end-point SW) 12. When the disconnection request is transmitted, the ATM switch (originating side ATM exchange, starting point SW) 10 which has received the disconnection request uses the optimum routing selection function to derive the routing result “ATM exchange 13 (back-up ATM ATM switch 13 (detour relay ATM switch, detour relay switch SW) using a signaling procedure that is automatically called based on the "call to ATM switch (destination ATM switch, destination SW) 12 via detour relay SW" instruction. AT via relay point SW)
The path is set so as to arrive at the M exchange (receiving side ATM exchange, end point SW) 12.

According to the present invention, an ATM switch (relay ATM switch, relay point SW) 11 and an ATM switch in a network are provided.
The restoration of the fault occurring between the exchanges (the receiving-side ATM exchange and the end point SW) 12 makes it possible to switch the detour path 15 back to the working path 14.

FIG. 2 shows the ATM switch (originating AT) shown in FIG.
M exchange, starting point SW) 10, ATM exchange (AT on the receiving side)
FIG. 3 is a functional block diagram for explaining a configuration of an M exchange, an end point SW) 12. Each of the ATM switch (outgoing side ATM switch, start point SW) 10 and the ATM switch (receiving side ATM switch, end point SW) 12 is an input / output means 26 from a maintenance person or to a maintenance person, an exchange control means 20, an ATM switch control. Means 24 (ATM-SW) is provided. 27 indicates an external storage medium.

The exchange control means 20 has a PNNI function, So
ft-PVC function, switchback function, signaling function,
It has a fault control function. The Soft-PVC function
Active / detour path control function as current switching function,
And a function of storing a failure factor. In particular, in the present embodiment, a working path path information holding function for storing the path information of the working path 14 is added to the Soft-PVC function, and a switching path control function and a working path for holding the working path reservation status are provided as a switching function. The feature is that a reservation status holding function is provided. The ATM switch control means 24 has an ATM path setting function and a failure detecting function as functions related to the present invention in the switching function of the ATM exchange.

The function of the exchange control means 20 will be described in more detail. The exchange control means 20 is activated by a maintenance person of the ATM exchange, and transmits the port / virtual path information of the originating side, the address of the destination side, and the virtual path information to the ATM exchange (the originating side AT).
When an instruction is given to the M exchange 10 and the starting point SW) 10, the automatic routing is performed from the ATM exchange (originating side ATM exchange, starting point SW) 10 after performing the optimal routing selection function of the PNNI, and the ATM exchange ( It has a PNNI Soft-PVC function for setting a user path up to the receiving side ATM switch, the end point SW) 12. It is started by a maintenance person of the ATM exchange, and transmits the port / virtual path information of the transmission side, the address and the virtual path information of the reception side to the ATM exchange (the transmission side ATM exchange, the starting point S).
W) 10, when the optimum routing selection function of the PNNI is executed, an automatic call is made from the ATM exchange (originating side ATM exchange, starting point SW) 10, and the ATM exchange (the terminating side ATM exchange) is sent using a normal signaling procedure. PN to set the user path up to the end point SW) 12
It has an NI Soft-PVC function. Also, user paths are mainly due to network failures including line failures,
When the communication between the users is interrupted, the ATM exchange (originating ATM exchange, starting point SW) 10 disconnects the user path once and automatically uses the same procedure as when the maintenance person instructs. Has a Soft-PVC automatic switching function of selecting an optimal routing path as a network at the time of disconnection and restoring a user path. Furthermore, when the network is restored to the state before the failure, the user path automatically or manually switches back the user path set by the Soft-PVC function of the PNNI to the optimal routing before the failure occurs. Thereby, the most efficient operation of the network can be performed. As a result, there is an effect that the user path on the most efficient route as the network before the occurrence of the failure is guaranteed, so that the most efficient operation of the network and the reduction of the total network cost can be achieved.

Next, the operation based on the principle diagram of the present invention shown in FIG. 1 will be described. Subsequently, the operation of the embodiment shown in FIG. 2 will be described with reference to the control flow chart of the control device shown in FIGS. A description will be given using a signaling sequence diagram, and also an ATM path setting method for performing the operation of the present invention at high speed.

In the state before the occurrence of the failure shown in FIG. 1, the ATM switch (relay ATM switch, relay point SW) 11 and the ATM switch (receiving side ATM switch,
The maintenance person is notified of the restoration of the fault that has occurred between the end points SW) 12. In response to the restoration from the failure, the maintenance person instructs the ATM exchange (originating ATM exchange, starting point SW) 10 to switch back. The ATM switch (originating ATM switch, starting point SW) 10 receives an instruction from the maintenance person and stores the stored ATM switches (relay ATM switch, relay point S).
W) A call is re-established based on the optimum route (corresponding to the working path 14) information before a failure occurs between the ATM switch 11 and the ATM switch (terminating side ATM switch, end point SW) 12, and the normal call processing function is used. The working path 14 is reset between the ATM switch (originating ATM switch, starting point SW) 10, the ATM switch (relaying ATM switch, relaying point SW) 11, and the ATM switch (receiving side ATM switch, terminal point SW) 12 (FIG. 1). State after failure occurrence shown in FIG. 1 → state before failure occurrence).

A preparatory operation (accumulation of an optimum route) for guaranteeing the switchback operation will be described with reference to FIGS. 2 and 3 to 8. FIG. 3 shows a process (AT) for setting a bypass path due to a failure from the existing working path setting state.
FIG. 4 is a control flow chart showing a flow of an M exchange (a starting point switch process executed in an originating ATM exchange, a starting point SW) 10. Referring to FIG. 3, the ATM switch (originating ATM)
In the start point switch process executed in the exchange (start point SW) 10, when a failure is detected in the working path setting state (step S30), the failure factor is stored in the main storage device of the exchange control means 20 (step S31). In the case of a maintenance person's instruction or the first failure (YES in step S32), a detour path switching route list is created (step S3).
3), after sending the alternate path switching setup (step S34), after the normal call processing (CONNECT reception), holding the alternative path setting completion in the main memory of the exchange control means 20 (step S35), and then setting the alternative path setting state (Step S36). If the instruction is not a maintenance person's instruction or the first failure (NO in step S32), no processing is performed.

FIG. 4 shows a process (ATM exchange (originating side A) where an active path route information holding function is added to the control flow of FIG.
FIG. 4 is a control flow diagram for explaining a start point switch process executed by a TM switch and a start point SW) 10. Referring to FIG. 4, the ATM switch (originating ATM switch, starting point S
In the start point switch process executed in W) 10, when a failure is detected in the working path setting state (step S40), the cause of the failure is stored in the main storage device of the exchange control means 20 (step S41), and the maintenance person In the case of the instruction or the first failure (YES in step S42), creation of a bypass path switching path list (step S43), transmission of a bypass path switching setup (step S44), normal call processing (CONNECT reception), and the working path After holding the path information (step S45) and holding the completion of the bypass path setting in the main storage device of the exchange control means 20 (step S46),
The detour path is set (step S47). If the instruction is not a maintenance person's instruction or the first failure (step S42)
No), no processing is performed. In this way, by adding the working path route information holding function, the optimum route for executing the switchback is accumulated.

Next, the operation at the time of failure recovery will be described with reference to the control flow of FIGS. 3 to 8 and the signaling sequence diagram of FIG.
Operation of M exchange (originating side ATM exchange, start point SW) 10 and ATM exchange (terminating side ATM exchange, end point SW) 12
The following description focuses on the operation of (1).

FIGS. 5 and 6 are control flow charts showing the flow of the switch-back process (start-point switch process) at the time of failure recovery executed by the ATM switch (originating-side ATM switch, starting point SW) 10 of FIG. FIG. 9 is a signaling sequence diagram for explaining a return sequence at the time of failure recovery. First, an ATM switch (relay ATM switch, relay point SW) 11 and an ATM switch (reception-side ATM switch) in the network.
The maintenance person who knows the restoration of the failure between the exchanges and the end point SW) 12 is the ATM exchange (the originating side ATM exchange and the start point SW) 1
An instruction to switch back to 0 is issued. ATM exchange (calling side AT
When a failure is detected in the active path setting state (step S50), the M exchange (starting point SW) 10 (starting point SW in FIG. 9) responds to this by executing the control processing of FIG. The respective processes of initialization of a failure factor for the storage device (step S51), extraction of the working path route information from the main storage device of the exchange control means 20 (step S52), and transmission of the working path reservation setup (SETUP) (step S53) are executed. Then, it transmits composite information of the SETUP message, the failure occurrence forward path list, and the working path reservation instruction (failure occurrence forward path list, with working path instruction, signal 40 shown in FIG. 9). In addition, ATM exchange (calling side A
TM exchange, starting point SW) 10 (starting point SW in FIG. 9)
After a normal call process (CONNECT reception), a connect signal (signal 42 shown in FIG. 9) from the opposite station (relay point SW (relay ATM switch 11 in FIG. 9)) is received. , That is, the setting of the working path reserved in the main storage of the exchange control means 20 (step S5).
4), setting of the active path reservation to the ATM switch control means 24 (ATM-SW) (step S55) and transmission of the bypass path disconnection release signal (signal 56 shown in FIG. 9) (RE)
The release signal (signal 43 shown in FIG. 9) for disconnecting the bypass path 15 after reserving the working path 14 by executing each processing of (LEASE transmission) (the bypass relay point SW (the bypass route) in FIG. 9). 13)). The detour path disconnection release signal (the signal 43 shown in FIG. 9) includes detour path instruction information.

Thereafter, the ATM exchange (originating ATM exchange, start point SW) 10 (start point SW in FIG. 9) is connected to the opposite station (detour relay point SW (detour relay ATM exchange 1 in FIG. 9).
Release complete signal from 3)) (signal 44 shown in FIG. 9)
In response to this, the control processing of FIG. 6, that is, the reception check of the release completion signal (the signal 44 shown in FIG. 9) (step S60), the ATM switch control means 24 (A
TM-SW) detour path disconnection (step S61), AT
The setting of the working path to the M switch control means 24 (ATM-SW) (step S62), the completion of setting the working path to the main storage device of the exchange control means 20 (step S63), the setting of the main storage device of the exchange control means 20 The detour path 15 is disconnected and reserved by executing the processing of initializing the working path information (step S64) and shifting to the working path setting state (state before failure) (step S65). After setting the working path 14 and initializing the information, the working path 14 can return to the working path setting state (state before the failure).

FIGS. 7 and 8 show an ATM switch (an ATM on the receiving side).
FIG. 9 is a control flow chart showing a flow of a switchback process (endpoint switch process) at the time of failure recovery executed by the exchange (endpoint switch) 12; The ATM switch (terminating-side ATM exchange, terminating-point SW) 12 serving as an end point SW is an ATM exchange (outgoing side ATM switch).
Exchange, starting point SW) 10 and a setup signal (fault occurrence forward path list, with working path indication, received via relay ATM exchange 11, signal 4 shown in FIG. 9)
5), and in response to this, from the bypass path setting state (step S70), the control processing of FIG. 7, that is, holding of the working path reservation information in the main storage device of the exchange control means 20 (step S71), ATM switch control Means 24 (ATM-S
W), setting of the working path reservation (step S72), transmission of the working path reserved signal (CONNECT transmission, step S72)
73), the working path reservation information is stored in the main storage device of the exchange control means 20, then the working reservation path is set, and a connect signal indicating that the working path reservation has been completed (see FIG. 9). The signal 46) is sent to the ATM switch (originating side A).
It is transmitted to the TM exchange, starting point SW) 10 (starting point SW in FIG. 9) side, and shifts to a bypass path setting state (step S74).

Thereafter, the ATM exchange (terminating side ATM exchange, end point SW) 12 (end point SW in FIG. 9) sends a release signal for disconnecting the detour path (signal 47 shown in FIG. 9) to the detour relay point SW (detour relay ATM). Received from the exchange 13), and shifts to the bypass path setting state accordingly (step S80).
Then, the control processing of FIG. 8, that is, fetching the working path reservation information from the main storage device of the exchange control means 20 (step S8)
1), active path reservation check (step S82), AT
The M-switch control unit 24 (ATM-SW) disconnects the bypass path (step S83), and the ATM switch control unit 24
(ATM-SW) working path setting (step S8)
4), transmission of a working path set release completion signal (signal 48 shown in FIG. 9) (RELEASE COMP transmission, step S85), and holding of the working path setting completion in the main storage device of the exchange control means 20 (step S86). By executing each process, after the detour path 15 is disconnected and the working path 14 is set, a release completion signal (signal 48 shown in FIG. 9) indicating that the working path 14 has been set is sent to the ATM exchange (originating ATM). The exchange, the starting point SW) 10 (the starting point SW in FIG. 9) is returned to the working path setting state (the state before the failure) (step S87).

Setting a path when switching or switching back a path generally requires a large amount of time, and how to reduce the path switching time is an effective means for preventing quality deterioration in the event of a failure. FIGS. 10 to 17 show path setting methods for speeding up the setting. FIG. 10 shows a starting point S according to the present invention.
One embodiment of a path setting method at W (before the current path reservation),
FIG. 11 shows an embodiment of a path setting method at the start point SW (after working path reservation) according to the present invention, FIG. 12 shows an embodiment of a path setting method at the start point SW (after deleting the bypass path) according to the present invention, FIG. 13 shows an embodiment of a path setting method at the start point SW (after setting the working path) according to the present invention, FIG. 14 shows an embodiment of a path setting method at the end point SW (before working path reservation) of the present invention, FIG. 15 shows an embodiment of a path setting method at the end point SW (after working path reservation) according to the present invention, FIG. 16 shows an embodiment of a path setting method at the end point SW (after deleting the bypass path) according to the present invention, FIG. 17 is a diagram for explaining an embodiment of a path setting method at the end point SW (after setting the working path) according to the present invention. In the figure, a solid line indicates a set path, a dashed line indicates a logical reservation stored in the main memory of the exchange control means 20, T indicates a transmit link, R indicates a receive link, and ATM-SW indicates an ATM switch control means 24. means. In the embodiment of the present invention, quality deterioration is prevented by implementing such a path setting method.

As described above, according to the first embodiment, when the failure in the network is restored, the quality is maintained to the most efficient operation form as the network planned before the failure occurred. However, the ability to switch back manually or automatically maximizes the advantages of PNNI's Soft-PVC function (exchange control means 20), and overcomes its weaknesses to optimize the distribution of various resources in the network. It becomes possible.

(Second Embodiment) In the first embodiment, an instruction from a maintenance person is used as a trigger for automatic switch-back (failure recovery). However, the present invention is not limited to this. In another embodiment using a method of detecting a failure recovery from the PNNI's Floating function, the originating ATM switch periodically performs the control processing of FIG. 5 (that is, initialization of a failure factor for the main storage device of the switching control means 20 (step S51)). Another embodiment is also possible in which the working path route information is extracted from the main storage device of the exchange control means 20 (step S52) and the working path reservation setup (SETUP) transmission (step S53) is performed. If these opportunities are adopted, the ATM switch will automatically perform the switchback processing without any intervention by a maintenance person. In a network where maintenance person intervention is not so desired, a large maintenance cost is required. Reduction can also be expected.

It should be noted that the present invention is not limited to the above embodiments, and it is clear that the embodiments can be appropriately modified within the scope of the technical idea of the present invention. Further, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment,
The number, position, shape, and the like suitable for carrying out the present invention can be obtained. In each drawing, the same components are denoted by the same reference numerals.

[0027]

As described above, according to the present invention, when the failure in the network is restored, the quality is maintained to the most efficient operation form as a network planned before the failure occurs. By switching back manually or automatically, it is possible to maximize the advantages of PNNI's Soft-PVC function and overcome its weaknesses to optimize the allocation of various resources in the network. This has the effect of becoming

[Brief description of the drawings]

FIG. 1 is an operation principle diagram of an ATM switching system and a path switching / returning method according to the present invention.

FIG. 2 is a functional block diagram for explaining a configuration of an ATM exchange as a start point SW or an ATM exchange as an end point switch of FIG. 1;

FIG. 3 is a control flow chart showing a flow of a start point switch process for setting a detour path due to a failure from an existing working path setting state.

FIG. 4 is a control flow chart for explaining a process in which an active path route information holding function is added to the control flow of FIG. 3;

FIG. 5 is a control flow chart showing a flow of a switch-back process (start-point switch process) at the time of recovery from a failure executed by the ATM exchange (originating-side ATM exchange, start-point SW) of FIG. 1;

FIG. 6 is a control flow chart showing a flow of a switch-back process (start-point switch process) at the time of failure recovery executed by the ATM switch (originating-side ATM switch, starting point SW) 10 of FIG.

FIG. 7 shows an ATM exchange (terminating side ATM exchange, end point S).
FIG. 14 is a control flowchart showing a flow of a switchback process (end point switch process) at the time of failure recovery executed by W).

FIG. 8 shows an ATM exchange (terminating side ATM exchange, end point S).
FIG. 14 is a control flowchart showing a flow of a switchback process (end point switch process) at the time of failure recovery executed by W).

FIG. 9 is a signaling sequence diagram for explaining a return sequence at the time of failure recovery.

FIG. 10 is a view for explaining an embodiment of a path setting method (before a current path reservation) at a starting point SW according to the present invention.

FIG. 11 is a diagram for explaining an embodiment of a path setting method (after working path reservation) at a starting point SW according to the present invention.

FIG. 12 is a diagram for explaining an embodiment of a path setting method (after detour path deletion) at the starting point SW according to the present invention.

FIG. 13 is a diagram for explaining an embodiment of a path setting method (after setting an active path) at a starting point SW according to the present invention.

FIG. 14 is a diagram for explaining an embodiment of a path setting method at the end point SW (before the current path reservation) according to the present invention.

FIG. 15 is a diagram for explaining an embodiment of a path setting method (after a working path reservation) at an end point SW according to the present invention.

FIG. 16 is a diagram for explaining an embodiment of a path setting method (after detour path deletion) at the end point SW according to the present invention.

FIG. 17 is a diagram for explaining an embodiment of a path setting method at the end point SW (after setting the working path) according to the present invention.

[Explanation of symbols]

10 ATM switch (originating ATM switch, starting point SW) 11 ATM switch (relaying ATM switch, relaying point SW) 12 ... ATM switch (receiving side ATM switch, terminal point SW) 13 ... ATM switch (rerouting relay ATM switch, detour) Relay point SW) 14 working path 15 detour path 20 exchange control means 24 ATM switch control means (ATM-SW) 26 input / output means 27 external storage means

Claims (12)

[Claims] 1. An ATM switching system which guarantees a user path on a most efficient route as a network before a failure occurs to achieve the most efficient operation of the network and reduce the total network cost. Means for performing a PNNI routing function for automatically generating optimal routing information as a network by communicating between ATM exchanges changes in various elements forming the network by performing a routing function and minimizing network maintenance intervention; and Means for performing a PVC function for automatically setting up an alternative path for a network failure in place of a maintenance person when the PNNI routing function is performed and for hiding a network failure from an end user; Network using the above-mentioned PVC function. When a user path that has been selected and set as the optimal path as a network is once detoured to another path due to a network failure such as a line failure, the path is optimal as the network that was selected before the failure recovery. Means for executing an optimal routing selection function of the PNNI for switching a user path to a proper path. 2. An ATM switching system which guarantees a user path on the most efficient route as a network before the occurrence of a failure to achieve the most efficient operation of the network and reduce the total network cost. Means for performing a PNNI routing function for automatically generating optimal routing information as a network by communicating between ATM exchanges changes in various elements forming the network by performing a routing function and minimizing network maintenance intervention; and Means for executing the PNNI Floodging function of automatically calling for a network failure on behalf of a maintenance person, setting an alternative path, and concealing the network failure from an end user when executing the PNNI routing function; The PNNI P When a user path that has been selected and set as an optimal path as a network using the VC function is once detoured to another path due to a network fault such as a line fault, the user path is selected before the fault recovery. Means for executing a PNNI optimal routing selection function for switching a user path to an optimal route as a network. 3. The ATM exchange has exchange control means provided with the PVC function of the PNNI, wherein the exchange control means can be started by a maintenance person of the ATM exchange, and has a port / virtual port on the transmission side. After instructing the path information, the address of the called side, and the virtual path information to the calling side ATM exchange, and executing the optimal routing selection function of the PNNI, the automatic calling is executed from the calling side ATM exchange, and a predetermined signaling procedure is performed. 3. The ATM exchange according to claim 1, wherein the user exchange is configured to set a user path to the ATM exchange on the receiving side. 4. The switching control means of the originating ATM switch, when communication between users is interrupted mainly due to a network failure including a line failure, disconnects the user path once and automatically switches the user path. Has a PVC automatic switching function for selecting an optimal routing path as a network at the time of disconnection of the user path and restoring the user path by using the same procedure as instructed by a maintenance person. The ATM according to claim 3, wherein
Exchange system. 5. The switching control means, when the network is restored to a state before the failure, the PVC of the PNNI.
The ATM exchange according to any one of claims 2 to 4, further comprising a function of automatically or manually switching back a user path set by the function to an optimum routing before a failure occurs. system. 6. The switching control means according to claim 2, wherein said switching control means has an active path route information holding function of storing route information of an active path as accumulated information of an optimum route for executing switchback. AT according to any one of the above
M exchange system. 7. A path switching / returning method for guaranteeing a user path on the most efficient route as a network before a failure occurs, thereby achieving the most efficient operation of the network and reducing the total network cost. A PNNI routing step of automatically generating optimal routing information as a network by performing a routing step in the PNNI and minimizing the maintenance intervention of the network and communicating changes of various elements forming the network with each other by the ATM exchanges; When performing the PNNI routing step, a PVC step of automatically calling for a network failure on behalf of a maintenance person to set an alternative path and conceal a network failure from an end user; Optimal as a network using When a user path selected and set for a route is once set to be detoured to another route due to a network fault such as a line fault, the user is redirected to the optimal route as the network selected before the fault recovery. A PNNI optimum routing selection step of switching back a path. 8. A path switching / returning method for guaranteeing a user path on the most efficient route as a network before the occurrence of a failure, thereby achieving the most efficient operation of the network and reducing the total network cost. A PNNI routing step of automatically generating optimal routing information as a network by performing a routing step in the PNNI and minimizing the maintenance intervention of the network and communicating changes of various elements forming the network with each other by the ATM exchanges; When performing the PNNI routing step, the PNNI Floodging step of automatically calling for a network failure on behalf of a maintenance person to set an alternative path and conceal a network failure from an end user; and the PNNI PVC. Process When a user path that has been selected and set as the optimal path as a network is once detoured to another path due to a network failure such as a line failure, the path is optimal as the network that was selected before the failure recovery. A PNNI optimal routing selection step of switching a user path back to a proper path. 9. An exchange control step including the PVC step of the PNNI, wherein the exchange control step can be started by a maintenance person of an ATM switch, and includes port / virtual path information on a calling side and a called side. After instructing the originating ATM exchange of the address and the virtual path information to the originating ATM exchange, and executing the PNNI optimum routing selection step, the automatic originating is executed from the originating ATM exchange, and the destination side is exchanged using a predetermined signaling procedure. 9. The method according to claim 7, further comprising the step of setting a user path up to the ATM switch. 10. The switching control process of the originating ATM switch comprises the steps of: when communication between users is interrupted mainly due to a network failure including a line failure,
Automatic PVC switching for selecting the optimal routing path as the network at the time of disconnection of the user path and restoring the user path by using the same procedure as when the maintenance path is automatically instructed by disconnecting the user path once The path switching / switching-back method according to claim 9, comprising a step. 11. The switching control step includes the step of: when the network is restored to a state before the failure, the PV of the PNNI is restored.
The path according to any one of claims 8 to 10, further comprising a step of automatically or manually switching back the user path set in the step C to the optimum routing before the occurrence of the failure. Switching / returning method. 12. The switching control step according to claim 8, further comprising a current path path information holding step of storing path information of a current path as accumulated information of an optimum path for executing a switchback. The path switching / returning method according to any one of the above.