JP2001069152A - Automatic detour restriction method in ATM communication network, and ATM communication network - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To further restrict automatic detour during maintenance work in an ATM communication network capable of selectively performing automatic detour control according to a communication path. SOLUTION: The routing table 1 of the ATM exchange
7 sets and registers a detour communication path for each working communication path in the area 17a, and sets and registers whether or not automatic detour is possible. When a failure is detected, automatic detour is performed only when automatic detour is registered. The routing table further has an area 17b.
The maintenance person uses the setting means (not shown) to set the area 17b.
The temporary inhibition information. As a result, it is possible to further restrict the automatic detour for the maintenance work and reduce the load on the detour communication path.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improvement in detour control in an ATM (Asynchronous Transfer Mode) communication network.

[0002]

2. Description of the Related Art In an ATM communication network disclosed in Japanese Patent Application Laid-Open No. 9-93260, communication paths are divided into a rescue class and a non-rescue class, and a bypass communication path is set in advance for each of the rescue class communication paths. . When a failure occurs in the rescue class communication path, the communication path is automatically detoured to the detour communication path. However, when a failure occurs in the non-rescue class communication path, communication is stopped without performing the detour. In this way, the detour is restricted, and the burden on the detour communication path is reduced.

[0003]

However, in the above publication,
In the TM communication network, detour control is automatically performed for any failure in the rescue class communication path. Therefore, detour control is also performed for failures caused by network maintenance work, etc., and the load on the detour communication path is reduced. This could lead to a significant increase. Further, when the detour communication path is an ISDN line, a call is made to the ISDN line and a connection is made when a failure occurs, resulting in an inconvenience of an excessive charge. In order to prevent such inconveniences, it is conceivable to change the setting of the communication channel to be relieved during the above maintenance work, but it is possible to change the advanced detour setting system by mistake In addition, the work of returning to the original setting after the maintenance work is complicated.

Incidentally, Japanese Patent Application No. 10-191 filed by the present applicant.
No. 649 discloses an ATM communication network having a function of restricting automatic detouring when a communication failure occurs. But this A
The TM communication network does not have a function of limiting automatic detouring in two stages as in the present invention.

[0005]

According to a first aspect of the present invention, there is provided:
An AT which includes a plurality of ATM exchanges and a plurality of communication paths connecting the ATMs, and which automatically diverts data from the communication path to another communication path by the ATM exchange when a failure occurs in the communication path.
In the M communication network, for the ATM exchange, whether the automatic detour is enabled or disabled is selectively set for each communication path, and only when a failure occurs in the communication path for which the setting is enabled. Execute the automatic detour, and further execute the ATM
A temporary prohibition of the automatic detour is set for the exchange, and the setting of the temporary prohibition is prioritized over the setting of the automatic detour enabled.

[0006] A second aspect of the present invention is the ATM of the first aspect.
In the automatic detour restriction method for a communication network, the setting of the temporary prohibition of the automatic detour is performed for each communication path.
According to a third aspect of the present invention, in the automatic detour restriction method for an ATM communication network according to the second aspect, the setting of temporarily prohibiting the automatic detour for each communication path is collectively released. According to a fourth aspect of the present invention, in the automatic detour restriction method for an ATM communication network according to the first aspect, the temporary prohibition of the automatic detour is set collectively for all communication paths and released collectively. Features.

A fifth aspect of the present invention is a method according to the first to fourth aspects.
In the automatic detour limiting method for a TM communication network, a communication path is used to determine whether an automatic switching back from a detour communication path to the communication path is permitted or disabled when a failure in the communication path is resolved. Selectively setting each time, further setting a temporary prohibition of automatic reverting in the ATM exchange, and giving priority to the setting of temporarily prohibiting the automatic reverting over the setting of the automatic reverting possible. I do.

A sixth aspect of the present invention comprises a plurality of ATM exchanges and a plurality of communication paths linking the plurality of ATM exchanges, wherein each of the ATM exchanges comprises (a) means for detecting a failure in a communication path; Routing control means for automatically diverting data from a communication path in which a failure is detected to a corresponding detour communication path in response to the failure detection by the failure detection means.
In the TM communication network, the ATM switch selectively sets (c) whether automatic detour to the detour communication path is enabled or disabled for each communication path, and sets temporary inhibition of automatic detour. (D) registration means for registering the information of the automatic detour selective setting, and (e) storage means for storing the information of the temporary prohibition of the automatic detour, wherein the routing control means The automatic detour is executed on condition that the automatic detour is registered by the registration means for the communication path in which the fault is detected, and that the temporary prohibition is not stored in the storage means.
The automatic detour is not executed when the temporary prohibition is stored in the storage unit.

A seventh aspect of the present invention is directed to the ATM according to the sixth aspect.
In the communication network, the setting means sets a temporary prohibition of the automatic detour for each communication path, and the storage means responds to the setting by the setting means and stores the information of the temporary prohibition for each communication path. It is characterized by storing. According to an eighth aspect of the present invention,
In the ATM communication network according to a seventh aspect, the setting means has a function of collectively releasing the temporary prohibition for each communication path in the storage means. According to a ninth aspect of the present invention, in the ATM communication network of the sixth aspect, the setting means sets the temporary inhibition of the automatic detour collectively for all communication paths, and the storage means sets all the communication paths. And a function of storing information of temporary prohibition in response to the setting by the setting means, and the setting means having a function of collectively releasing the temporary prohibition of the storage means. It is characterized by the following.

A tenth aspect of the present invention is the ATM communication network according to the sixth to ninth aspects, further comprising the step of automatically switching from the bypass communication path to the communication path when the failure in the communication path is resolved. The registration unit also has a function of selectively setting whether to enable or disable return for each communication path, and a function of setting a temporary prohibition of automatic return. The setting means also stores information on the temporary prohibition of the automatic switchback, and the routing control means confirms that the automatic switchback is registered by the registration means. On the condition that the temporary prohibition of the automatic switchback is not stored by the means, the automatic switchback from the bypass communication path to the communication path in which the failure has been resolved is executed, and the temporary prohibition of the automatic switchback is performed by the storage means. Is remembered Characterized in that it does not run back the cut. An eleventh aspect of the present invention is the ATM communication network according to the sixth to tenth aspects, wherein the communication path is a physical line, a virtual path, a bundle of a plurality of virtual channels in a virtual path, or a virtual channel as a unit. It is characterized by doing.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 to 5 show a first embodiment of the present invention. FIG. 1 shows three (multiple) ATMs as part of an ATM network.
Exchanges 1a to 1c (hereinafter simply referred to as exchanges) and a plurality of physical lines 3 to 9 connected to these exchanges 1a to 1c.
Is shown. Maintenance devices 2a to 2c (setting means) are connected to the exchanges 1a to 1c, respectively.

Next, the configurations of the exchange 1a and the maintenance device 2a corresponding to the data flow indicated by the arrows will be described. The other exchanges 1b and 1c, the maintenance devices 2b and 2c
Has the same configuration as that of the exchange 1a and the maintenance device 2a, and a detailed description thereof will be omitted. As shown in FIG. 2, the exchange 1a includes a switch device 10 for switching a flow of a cell including data according to a cell header, input-side network IF devices 11 and 12 corresponding to the physical lines 3 and 4, Output-side network IF devices 13 and 14 corresponding to lines 5 and 6
And a monitoring control device 15. The network IF devices 11 to 14 are connected to a connection interface with a line and an AT.
Provides the function of the M layer.

The monitoring and control device 15 includes the fault detecting means 1
6, routing table 17, writing means 18
And routing control means 19. The fault detecting means 16 monitors each component in the exchange 1a to detect the fault, and detects a fault in the physical lines 3 to 7 by transmitting and receiving a fault monitoring cell. The writing means 18 is for writing information input by a maintenance person by operating the maintenance device 2a into the routing table 17. The routing control means 19 includes:
Based on the fault detection information in the fault detecting means 16 and the information stored in the routing table 17, the switching control described below is performed by setting the switch device 10.

The routing table 17 accumulates (registers and stores) information on detours corresponding to all VCs (virtual channels, communication channels in the claims). FIG. 5A illustrates information on a VC whose VPI (virtual path identifier) is specified as Px and whose VCI (virtual channel identifier) is specified as Cm. Note that, in order to distinguish the VC to which the detour information is attached from a detour VC to be described later, the VC is hereinafter referred to as “working VC” for convenience. Here, each physical line 3 ~
Assuming that each VC has 10 channels in 10 channels, 4 × 1
There will be 0 = 40 routing tables.

As shown in FIG. 5A, the current VC (VP
A detour VC (VPI = Py, VCI = Cn) is registered as a detour communication path for I = Px, VCI = Cm). The above-mentioned working VC (VPI = Px, VCI = C
m) is on the physical line 5 and the bypass VC (VPI = P
y, VCI = Cn) is on the physical line 6 (see FIG. 4).
Further, information indicating whether the automatic detour to the detour VC is “permitted” or “impossible” is registered for each active VC. In the case of a working VC that is highly important and needs to be rescued, “OK” is registered as shown in the figure.
Register as "impossible". In addition, information indicating whether automatic switchback from the bypass VC to the active VC is “permitted” or “impossible” is registered for each active VC. In the present embodiment, the case where the automatic detour is “possible” is shown, and the “return is possible” that automatically returns to the original state when the failure is recovered is shown. It goes without saying that the automatic detour may be "possible" or "return impossible". The area 17a for storing the information of the bypass VC corresponding to the active VC and the information of “permitted” and “impossible” of the automatic detour and the automatic switchback corresponds to a registration unit in the claims.

Further, the table 17 has an area 17b for storing information on the setting of temporarily prohibiting the automatic detour and the setting of temporarily prohibiting the automatic switching back for each active VC. In the illustrated example, the temporary prohibition of the automatic detour in the state of the automatic detour in the automatic switching registration is set, and the temporary prohibition of the automatic reverting in the state of the automatic reversion is set. This area 17b corresponds to the storage means in the claims.

The operation of the ATM communication network having the above configuration will be described. The maintenance person inputs (sets) necessary information including the detour information to the exchange 1a by operating the maintenance device 2a in advance. That is, the detour VC is input for each of the active VCs, and the information of “permitted” and “impossible” of the automatic detour and switchback is input. The writing means 18 writes the input information into the area 17a of the routing table 17.

When there is no maintenance work or the like, no temporary prohibition is set in the area 17b of the routing table 17. In this case, the routing control means 19
The detour control is performed based on the detour information registered in the area 17a of the routing table 17. The details will be described below.

When a fault occurs in the physical line 5, the fault detecting means 16 detects the fault in the physical line 5 and also detects the fault in all the working VCs passing through the physical line 5. The routing control means 19 executes the routing control according to the protocol of FIG. 3 in response to the failure detection. That is, it is determined from the storage contents of the area 17b whether or not there is a setting for temporarily prohibiting the automatic detour for the active VC in which the failure has been detected (this determination step is indicated by S1 in FIG. 3).

As described above, when there is no maintenance work, since the area 17b does not store (set) the temporary inhibition, it is determined in step S1 that the inhibition setting has been released.
The next judgment step S2 is executed. In this step S2, it is determined whether any of "permitted" and "impossible" of the automatic detour is registered in the area 17a. Here, when it is determined to be “permitted”, it is switched to the bypass VC registered in the area 17a. As a result, when a failure occurs in an important working VC, data to be passed through the working VC can be transmitted via the bypass VC. For example, physical line 5 shown in the figure
From the above working VC (VPI = Px, VCI = Cm) to the detour VC (VPI = Py, VCI = Cn) on the physical line 6
Detour to.

When it is determined in step S2 that "impossible", the automatic detour to the detour VC is not performed. As a result, for the inactive VC that is not important, the detour VC
The burden on the user can be reduced. By operating the maintenance device 2a, the maintenance person can instruct a detour to a previously registered detour VC as necessary even if the registration of “impossible” has been made. (Manual detour).

After the automatic detour is performed, when the active VC is cleared and the fault is recovered or when a fault in the detour VC is detected, the area 17 is processed in the same flow as the above protocol.
Automatic switchback to the current VC is performed based on the registration of automatic switchover permitted in step a.

Next, the most important operation will be described.
When performing maintenance work on the physical line 5 and the like, the maintenance person can further restrict the automatic detour due to the occurrence of a failure due to the maintenance work. More specifically, by the input operation on the maintenance device 2a, the temporary prohibition of the automatic detour is selectively set for each of the active VCs for which the automatic detour “permitted” is set,
The information of the temporary prohibition is written into the area 17 b of the routing table 17 via the writing means 18. As described above, when determining in step S1 in response to the failure detection as described above, the routing controller 19 does not execute the automatic detour if the temporary inhibition is set for the active VC in which the failure is detected. As a result, it is possible to prevent the detour VC from being overburdened during maintenance work. Note that, for a very important working VC, the temporary prohibition is not set, so that an automatic detour to the detour VC can be executed, and data communication can be reliably performed.

When the maintenance is completed, the maintenance person operates the maintenance device 2a to collectively reset (initialize) the temporary prohibition setting in the area 17b for all the working VCs. In the area 17a, the information on the “permitted” and “impossible” of the automatic detour remains registered, so that the original state, that is, the selective automatic operation based on the registered information of “permitted” and “impossible” can be easily and reliably performed. It is possible to return to the state of the detour control.

In the area 17b of the routing table 17, it is possible to set a temporary prohibition of switching back from the detour VC to the working VC. That is, after the automatic detour is performed based on the registration of the automatic detour “Yes” in the area 17a, when the working VC is restored or a failure occurs in the detour VC, the area 17a
a, the automatic switch back to the current VC is temporarily prohibited, and the automatic VC
It is possible to respond to various requests of the user, for example, when the user wants to manually switch back after confirming the failure.

In the above embodiment, the working communication path and the bypass communication path are set in VC units, but may be set in larger units. For example, the communication path may be a VP unit. In this case, the VCI is undefined in FIG. Also, V
A bundle of a plurality of VCs in P may be used as a unit. In this case, each bundle is assigned a route identifier and registered in the routing table of FIG. In this case, the VCI is undefined. Further, as the largest unit, the communication path may be a physical line unit. In this case, since the VPI and VCI are not specified, the status is “undefined”, and the routing table 17 is illustrated in FIG. 5B.

In the above embodiment, the step S of the judgment
The order of 1, S2 may be reversed. In the above embodiment, the temporary prohibition of the automatic detour is set for each of the working communication paths. However, the temporary prohibition of the automatic detour may be set for all the working communication paths at once. In this case, the storage means is common to all working communication paths, not for each working communication path, and stores the collective temporary inhibition information. Also,
Temporary prohibition may be set for each large unit of communication path including a plurality of communication paths for which “permitted” and “impossible” for automatic detour are set. In this case, the storage unit stores the temporary prohibition information for each of the large units of communication paths. For example, when setting “permitted” or “impossible” for automatic detour for each VC, for each VC bundle, VP
When the temporary prohibition is set for each physical line and the setting of “permitted” or “impossible” for the automatic detour for each VC bundle or VP, the temporary prohibition is set for each physical line. When setting a bypass communication path in units of VCs or VPs, the working communication path and the bypass communication path may be the same physical line.

The storage means for temporary prohibition may be constituted by a memory which is more volatile than the registration means for "permitted" and "impossible" of automatic detour. In the above embodiment, instead of setting a bypass communication path for each of the working communication paths, a bypass communication path may be set (registered) only for a working communication path having a high degree of importance. In this case, setting the bypass communication path itself means registration of “permitted” for automatic bypass. A bypass communication path is not set for a less important working communication path, and this means that the automatic bypass is “impossible”. The ATM switch may have a CLAD device. The communication path targeted for the failure detection and the detour control may include an ATM switch. Each working communication path may be set as a bypass communication path for another working communication path.
The setting means for setting the detour information may be a special maintenance device common to many exchanges, instead of the maintenance device provided for each exchange as in the above-described embodiment. Especially when setting a temporary ban, the maintenance equipment of one exchange
Temporary prohibition in a plurality of exchanges may be set. The setting means for registering “permitted” and “impossible” of the automatic detour and the setting means for temporarily prohibiting the automatic detour may be provided separately.

In the second embodiment shown in FIG. 6, an ISDN line 20 is used as a bypass communication path. In this case, when a failure occurs in the active communication path, a call is made to the ISDN line and connection is made. However, as in the above-described embodiment, automatic detouring is restricted in two stages. Excessive charges can be prevented.

As in the third embodiment shown in FIG. 7, the adjacent exchanges 1a and 1c may be connected by double physical lines 5a and 5b. In FIG. 7, other exchanges and physical lines are not shown, but the configuration is similar to that of the ATM communication network of the first embodiment except that the physical lines are duplicated. In this case, one physical line 5a is used as a working communication path,
The other physical line 5b can be used as a bypass communication path.

[0031]

As described above, the first and sixth embodiments of the present invention are described.
According to the aspect, when there is no maintenance work, selective automatic detour control is performed based on setting information indicating whether automatic detour is possible or not for each communication path, and automatic detour is temporarily prohibited during maintenance work or the like. The burden on the road can be reduced, and excessive cost burden caused by detour can be avoided. Further, the temporary prohibition of the automatic detour is performed while maintaining the setting of whether or not the automatic detour is allowed. Therefore, by canceling the temporary prohibition, the original selective automatic detour control is reliably returned to. And prevent accidental modification or destruction of a highly configured detour system. According to the second and seventh aspects of the present invention, a temporary prohibition is set for each communication path, so that data communication on an extremely important communication path can be performed even when maintenance work is being performed. Can be run through According to the third and eighth aspects of the present invention, by temporarily releasing the temporary prohibition, it is possible to easily return to the original selective automatic detour control. According to the fourth and ninth aspects of the present invention, the temporary prohibition of the automatic detour can be easily performed during maintenance work by setting the temporary prohibition collectively. According to the fifth and tenth aspects of the present invention, by temporarily prohibiting automatic switchback, it is possible to respond to various demands of the user, for example, when the user wants to switch back manually after confirming the failure detection.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing a part of an ATM communication network according to a first embodiment of the present invention.

FIG. 2 is a block diagram of an ATM switch used in the ATM communication network.

FIG. 3 is a diagram showing a protocol for routing control when a communication path failure is detected in the ATM exchange.

FIG. 4 is a schematic diagram showing an example of a working virtual channel and a bypass virtual channel in the first embodiment.

FIGS. 5A and 5B are diagrams showing contents of a routing table used in different examples from each other in the first embodiment.

FIG. 6 is a schematic block diagram showing a part of an ATM communication network according to a second embodiment of the present invention.

FIG. 7 is a schematic block diagram showing a part of an ATM communication network according to a third embodiment of the present invention.

[Explanation of symbols]

 1a-1c ATM exchange 2a-2c Maintenance device (setting means) 3-9 Physical line 16 Failure detecting means 17 Routing table 17a Routing table area (registering means) 17b Routing table area (storage means) 19 Routing control means

Claims (11)

[Claims] 1. An ATM communication network comprising a plurality of ATM exchanges and a plurality of communication paths connecting the ATM exchanges, wherein the ATM exchange automatically diverts data from the communication path to another communication path when a failure occurs in the communication path. In the ATM switch, whether the automatic detour is permitted or not is selectively set for each communication path, and the automatic switching is performed only when a failure occurs in the communication path for which the setting is possible. Automatic detouring in the ATM communication network, wherein a temporary prohibition of automatic detouring is set for the ATM exchange, and the temporary prohibition setting is prioritized over the automatic detouring possible setting. Restriction method. 2. The ATM according to claim 1, wherein the setting of the temporary prohibition of the automatic detour is performed for each communication path.
An automatic detour restriction method in a communication network. 3. The automatic detour restriction method in an ATM communication network according to claim 2, wherein the setting of the temporary prohibition of the automatic detour for each communication path is released collectively. 4. The automatic bypass restriction in an ATM communication network according to claim 1, wherein the temporary prohibition of the automatic bypass is set collectively for a plurality of or all communication paths and is released collectively. Method. 5. An ATM exchange, which selectively enables or disables automatic switching back from a bypass communication path to a communication path when a failure in the communication path is resolved. 2. The method according to claim 1, further comprising: setting a temporary prohibition of automatic reverting in the ATM switch, wherein the setting of the temporary prohibition of the automatic reverting is given priority over the setting of the automatic reverting enabled. 4. The method for restricting automatic detour in an ATM communication network according to any one of 4. 6. A communication system comprising a plurality of ATM exchanges and a plurality of communication paths linking the plurality of ATM exchanges, wherein each of the ATM exchanges comprises: (a) means for detecting a failure in a communication path; and (b) failure detection by the failure detection means. In response to an ATM communication network, the ATM switch further comprises: routing control means for automatically diverting data from a communication path in which a failure is detected to a corresponding detour communication path. Setting means for selectively setting whether automatic detour to the detour communication path is permitted or not for each time, and setting temporary inhibition of automatic detour, and (d) selective setting of the automatic detour And (e) storage means for storing the information of the temporary prohibition of the automatic detour, wherein the routing control means automatically registers the communication path in which the fault is detected by the registration means. Detour The automatic detour is executed on condition that the temporary prohibition is stored in the storage means, and the automatic detour is executed if the temporary prohibition is stored in the storage means. An ATM communication network characterized by not performing. 7. The setting means sets a temporary prohibition of the automatic detour for each communication path, and the storage means responds to the setting by the setting means and stores the information of the temporary prohibition for each communication path. The ATM communication network according to claim 6, wherein: 8. The ATM communication network according to claim 7, wherein said setting means has a function of collectively releasing temporary inhibition for each communication path in said storage means. 9. The setting means collectively sets the temporary prohibition of the automatic detour for a plurality of or all communication paths, and the storage means is common to the plurality or all the communication paths. 7. The method according to claim 6, further comprising the step of storing information of the temporary inhibition in response to the setting by the setting means, and further comprising a function of the setting means canceling the temporary inhibition of the storage means collectively. An ATM communication network as described. 10. The communication device according to claim 1, wherein the setting unit selectively determines whether automatic switching back from the detour communication path to the communication path is enabled or disabled when the failure in the communication path is resolved. The registration means also has a function of setting and a function of setting a temporary prohibition of the automatic switchback. The registration means also registers the selective setting of the automatic switchback, and the storage means temporarily stores the automatic switchback. Prohibition information is also stored, and the routing control means is provided on condition that automatic registration is permitted by the registration means, and that temporary storage of automatic return is not stored in the storage means. Performing automatic switchback from the detour communication path to the communication path in which the failure has been resolved, and not executing the switchback if temporary storage of automatic switchback is stored in the storage means. Claims 6 to 9 ATM communication network according to any deviation. 11. The communication path according to claim 6, wherein the communication path is a unit of one of a physical line, a virtual path, a bundle of a plurality of virtual channels in the virtual path, and a virtual channel. ATM communication network.