JPH1093579A - Alarm cell generating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the alarm cell generating system in which a frequency band used by an alarm cell is decreased and occurrence of a fault is correctly delivered to a termination node of the alarm cell even on the occurrence of a loss of the alarm cell or of multiple fault. SOLUTION: An alarm cell production node A starts production of a fault notice cell (a) on the occurrence of a fault and keeps generating periodically the fault notice cell (a) till the node A receives a fault notice reception cell (b) sent back from an alarm cell termination node B. The alarm cell production node A starts production of a recovery notice cell (c) on the recovery of fault and keeps generating the recovery notice cell (c) till the node A receives a recovery notice reception cell (d) sent back from the alarm cell termination node B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alarm cell generation system, and more particularly to an ATM (Asynchronous T).
transfer mode (Asynchronous transfer mode) When a transmission line or path fails in a network, all VPs (virtual) accommodated in the transmission line or path
The present invention relates to a method for generating an alarm cell for promptly and reliably notifying a terminal point of 1 Path (virtual path) that a VP cannot be used.

[0002]

2. Description of the Related Art Generally, this type of alarm cell generation method is called A
When a transmission line or path failure occurs in the TM network, the termination point of all the VPs accommodated in the transmission line or path where the failure occurred is notified promptly and reliably that the VP cannot be used. Used for

Conventionally, as a method for generating an alarm cell in this type of ATM device, as shown in FIG. 7, an alarm cell is continuously generated while a failure occurs, and an alarm is generated when the failure is recovered. There is a cycle generation method for stopping generation of cells.

[0004] As another method of generating an alarm cell,
As shown in FIG. 8, there is a change point notification method in which a failure notification cell is generated when a failure occurs and a recovery notification cell is generated when the failure is recovered, thereby notifying the occurrence and recovery of the failure.

First, the period generation method will be described in detail with reference to FIG. An alarm cell generating node (hereinafter, referred to as an alarm cell generating point) D is a terminal node of an alarm cell (hereinafter, referred to as an alarm cell terminal point) in which a failure has occurred in a transmission path between the preceding node and the node. , The generation of an alarm cell k is started [see FIG. 7 (a)]. The alarm cell generating point D keeps generating the alarm cell k periodically at a constant interval with respect to the alarm cell terminal point E during the occurrence of the failure (see FIG. 7B).

The alarm cell generating point D stops generating the alarm cell k when the fault is recovered (see FIG. 7C). When receiving the alarm cell k from the alarm cell occurrence point D, the alarm cell terminal point E detects the occurrence of the failure, and recognizes that the failure is occurring while the alarm cell k is being periodically detected. If the alarm cell terminal point E does not receive the alarm cell k from the alarm cell generation point D for a certain period of time, it detects recovery from the failure.

Next, the change point notification method will be described in detail with reference to FIG. When a failure occurs in the transmission path between the alarm cell generation point F and the preceding node, one failure notification cell 1 is generated for the alarm cell termination point G (see FIG. 8A). Further, when the alarm cell occurrence point F recovers from the failure,
One recovery notification cell m is generated for the alarm cell termination point G [see FIG. 8B]. At the alarm cell terminal point G, when the failure notification cell 1 is received from the alarm cell occurrence point F, the occurrence of a failure is detected, and similarly, when the recovery notification cell m is received, the recovery of the failure is detected.

[0008]

In the conventional alarm cell generation method described above, in the case of the periodic generation method, as shown in FIG. 7, when the alarm cell generation point D has a failure, the generation of the alarm cell k starts. The alarm cell k continues to be generated periodically at regular intervals during the occurrence of a failure, and the generation of the alarm cell k is stopped when the failure is recovered. The alarm cell termination point E detects the occurrence of a failure when the reception of the alarm cell is started, and detects the recovery from the failure by not receiving the alarm cell k for a predetermined time. Therefore, in the periodic generation method, the band used by the alarm cell during the occurrence of a failure increases.

Further, in the case of the change point notifying method for solving the problem that the band used by the alarm cell increases during the occurrence of a failure in the period generation method, as shown in FIG. Point F generates one failure notification cell l,
When the fault is recovered, the alarm cell generation point F is set to the recovery notification cell m.
Is generated.

Therefore, in the change point notifying method, the band used by the alarm cell can be made smaller than that in the period generating method. Since only one m is generated each time, when the failure notification cell 1 or the recovery notification cell m is lost, the occurrence of the failure or the recovery from the failure cannot be correctly transmitted to the alarm cell terminal point G. Therefore, when the alarm cell is lost and multiple failures occur, the existence of the failure cannot be correctly transmitted to the alarm cell terminal point G.

Further, in the change point notifying method, as shown in FIG. 9, when a multiple failure occurs, an alarm cell occurrence point (first failure) H is first set to a failure notification cell with respect to the alarm cell terminal point I when a first failure occurs. (First failure) n is generated. When the alarm cell termination point I receives the failure notification cell (first failure) n,
Perform line blocking processing.

Next, if a subsequent failure occurs during the occurrence of the first failure, the alarm cell occurrence point (late failure) J generates a failure notification cell (late failure) o with respect to the alarm cell terminal point I.
Since the first failure has occurred between the alarm cell occurrence point (late failure) J and the alarm cell occurrence point (first failure) H, the failure notification cell (late failure) p is not transmitted to the alarm cell end point I. At the alarm cell terminal point I, it is not possible to recognize the occurrence of the subsequent failure.

Thereafter, when the advanced failure recovers during the occurrence of the subsequent failure, the alarm cell occurrence point (advance failure) H generates a recovery notification cell (advance failure) p to the alarm cell end point I. At the alarm cell termination point I, the recovery notification cell (preceding failure) p is received, and the blockage of the line is released despite the occurrence of the subsequent failure. As described above, according to the change point notification method, the existence of a failure cannot be correctly transmitted to the alarm cell terminal point I when multiple failures such as a first failure and a second failure occur.

Accordingly, an object of the present invention is to solve the above-mentioned problems, to reduce the band used by the alarm cell, and to determine the existence of a failure even when the alarm cell is lost or multiple failures occur. It is an object of the present invention to provide an alarm cell generation system capable of correctly transmitting information to an alarm cell.

[0015]

SUMMARY OF THE INVENTION An alarm cell generation system according to the present invention provides, to an alarm cell, the fact that the virtual path is unusable to the end nodes of all virtual paths accommodated in a transmission line and a path. An alarm cell generation system that notifies the terminal node when the failure detection unit detects any failure of the transmission line and the path. A first transmission unit for transmitting the failure notification cell, and a failure notification reception cell from the terminal node indicating that the failure notification cell has been received, the first transmission unit being preset from the first transmission unit. First control means for controlling transmission of the failure notification cell at regular intervals; recovery detection means for detecting recovery of the failure detected by the failure detection means; When detecting the recovery of the failure detected by the failure detection means, the second transmission means for transmitting a notification cell of the recovery to the end node, the indicating that the notification cell of the recovery has been received A second control means for controlling transmission of the recovery notification cell at a predetermined interval from the second transmission means until a recovery notification reception cell from the terminal node is received. Have.

As described above, the alarm cell generation method of the present invention starts the generation of a failure notification cell when a failure occurs, and starts the failure notification from the alarm cell generation point until the failure notification reception cell returned from the alarm cell termination point is received. Notification cells continue to be generated periodically, recovery notification cells start to be generated at the time of failure recovery, and recovery notification cells continue to be generated from the alarm cell generation point until a recovery notification reception cell sent back from the alarm cell termination point is received.

In this case, the alarm cell termination point detects the occurrence of a failure when receiving the failure notification cell, sends back the failure notification reception cell to the alarm cell occurrence point, and detects the recovery of the failure when the recovery notification cell is received. At the same time, the recovery notification receiving cell is sent back to the alarm cell occurrence point.

Thus, while the alarm is being generated,
Since there is no need to periodically generate alarm cells at regular intervals, the band used by the alarm cells can be reduced. In addition, when a warning cell is lost and multiple failures occur, the existence of a failure can be correctly transmitted to the terminal point of the warning cell.

[0019]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an alarm cell generation node (hereinafter, referred to as an alarm cell generation point) according to an embodiment of the present invention. In the figure, a failure occurrence / recovery detection unit 1, a failure notification cell / recovery notification cell generation / insertion unit 2, a failure notification cell /
A recovery notification cell insertion instructing unit 3, a timer unit 4, and a failure notification receiving cell / recovery notification receiving cell detecting unit 5 are provided.

When a failure occurs in the transmission line, the failure occurrence / recovery detection unit 1 detects the occurrence of the failure in the transmission line, and instructs the failure notification cell / recovery notification cell insertion instructing unit 3 to generate the failure in the transmission line. Notice.

Failure notification cell / recovery notification cell insertion instructing unit 3
Receives a notification of the occurrence of a failure in the transmission path from the failure occurrence / recovery detection unit 1, generates a failure notification cell generation control signal for each fixed-time timing signal sent from the timer unit 4, The control signal is periodically sent to the failure notification cell / recovery notification cell generation / insertion unit 2 at regular intervals.

The failure notification cell / recovery notification cell generation / insertion unit 2 generates a failure notification cell based on the failure notification cell generation control signal sent from the failure notification cell / recovery notification cell insertion instructing unit 3 at regular intervals. Then, the generated fault notification cell is inserted into the transmission path and sent to the terminal node of the alarm cell (hereinafter referred to as alarm cell terminal point) (not shown).

When the failure notification receiving cell / recovery notification receiving cell detecting unit 5 receives the failure notification receiving cell sent from the alarm cell termination point, the failure notification receiving cell receiving signal is sent to the failure notification cell / recovery notification cell insertion instructing unit. Send to 3.

Failure notification cell / recovery notification cell insertion instructing unit 3
When receiving the failure notification reception cell reception signal from the failure notification reception cell / recovery notification reception cell detection unit 5, the generation of the failure notification cell generation control signal is stopped, and the failure notification cell / recovery notification cell generation and failure for the insertion unit 2 are stopped. The transmission of the notification cell generation control signal is stopped.

The failure notification cell / recovery notification cell generation and insertion unit 2 receives the stop of the failure notification cell generation control signal from the failure notification cell / recovery notification cell insertion instructing unit 3 and generates the failure notification cell and generates the failure notification cell. Stop insertion into the transmission path.

On the other hand, when the failure in the transmission path is recovered, the failure occurrence / recovery detecting section 1 detects the recovery of the failure in the transmission path, and instructs the failure notification cell / recovery notification cell insertion instructing section 3 to detect the failure in the transmission path. Notify recovery.

Failure notification cell / recovery notification cell insertion instructing unit 3
Receives a notification of failure recovery from the failure occurrence / recovery detection unit 1, generates a recovery notification cell generation control signal for each fixed-time timing signal sent from the timer unit 4, and generates the recovery notification cell generation control signal. It is periodically sent to the failure notification cell / recovery notification cell generation / insertion unit 2 at regular intervals.

The failure notification cell / recovery notification cell generation / insertion unit 2 generates a recovery notification cell based on the recovery notification cell generation control signal sent from the failure notification cell / recovery notification cell insertion instructing unit 3 at regular intervals. Then, the generated recovery notification cell is inserted into the transmission path and sent to the alarm cell termination point.

Upon receiving the recovery notification receiving cell transmitted from the alarm cell termination point, the failure notification receiving cell / recovery notification receiving cell detection unit 5 converts the recovery notification reception cell reception signal into a failure notification cell / recovery notification cell insertion instruction unit. Send to 3.

Failure notification cell / recovery notification cell insertion instructing unit 3
When the recovery notification receiving cell reception signal is received from the failure notification receiving cell / recovery notification receiving cell detection unit 5, the generation of the recovery notification cell generation control signal is stopped, and the failure notification cell / recovery notification cell generation and recovery notification to the insertion unit 2 are performed. The transmission of the cell generation control signal is stopped.

The failure notification cell / recovery notification cell generation / insertion unit 2 receives the suspension of the recovery notification cell generation control signal from the failure notification cell / recovery notification cell insertion instructing unit 3 and generates the recovery notification cell and generates the recovery notification cell. Stop insertion into the transmission path.

FIG. 2 is a block diagram showing a configuration of an alarm cell termination point according to an embodiment of the present invention. In the figure, an alarm cell termination point according to one embodiment of the present invention is a failure notification cell / recovery notification cell detection unit 6, a failure notification reception cell / recovery notification reception cell insertion instruction unit 7, a failure notification reception cell / recovery notification reception A cell generation and insertion unit 8;

Upon receiving the failure notification cell from the alarm cell generation point (not shown), the failure notification cell / recovery notification cell detection unit 6 notifies the failure notification reception cell / recovery notification reception cell insertion instruction unit 7 of the failure notification. Carries the cell reception signal.

When receiving the failure notification cell reception signal from the failure notification cell / recovery notification cell detection unit 6, the failure notification reception cell / recovery notification reception cell insertion instructing unit 7 receives the failure notification reception cell / recovery notification cell reception signal.
A failure notification reception cell generation control signal is sent to the recovery notification reception cell generation and insertion unit 8.

Upon receiving the failure notification receiving cell generation control signal from the failure notification receiving cell / recovery notification receiving cell insertion instructing unit 7, the failure notification receiving cell / recovery notification receiving cell generation / insertion unit 8 adds one failure notification receiving cell. Then, the failure notification receiving cell is inserted into the transmission path and sent to the alarm cell generation point.

When the failure notification cell / recovery notification cell detection unit 6 receives the recovery notification cell from the alarm cell occurrence point, the failure notification cell / recovery notification cell insertion instruction unit 7 sends a recovery notification cell reception signal to the failure notification cell / recovery notification reception cell insertion instruction unit 7. Tell

Upon receiving the recovery notification cell reception signal from the failure notification cell / recovery notification cell detection unit 6, the failure notification reception cell / recovery notification reception cell insertion instructing unit 7 receives the failure notification reception cell / recovery notification cell reception signal.
A recovery notification reception cell generation control signal is sent to the recovery notification reception cell generation and insertion unit 8.

Upon receiving the recovery notification reception cell generation control signal from the failure notification reception cell / recovery notification reception cell insertion instructing unit 7, the failure notification reception cell / recovery notification reception cell generation / insertion unit 8 selects one recovery notification reception cell. The cell is generated, the recovery notification receiving cell is inserted into the transmission line, and sent to the alarm cell generation point.

FIG. 3 is a flowchart showing the operation of the alarm cell generating point according to one embodiment of the present invention, FIG. 4 is a flowchart showing the operation of the alarm cell terminal point according to one embodiment of the present invention, and FIG. FIG. 5 is a diagram illustrating an operation of generating an alarm cell according to an embodiment of the present invention. FIG. 5A shows an operation at the time of occurrence of a failure, and FIG. 5B shows an operation at the time of failure recovery. The operation of generating an alarm cell according to one embodiment of the present invention will be described with reference to FIGS.

When the failure occurrence / recovery detection unit 1 at the alarm cell occurrence point A detects the occurrence of a failure in the transmission line with the preceding node (step S1 in FIG. 3), the failure notification cell / recovery notification cell insertion instruction unit 3 is notified of the occurrence of a failure in the transmission path.

Failure notification cell / recovery notification cell insertion instructing unit 3
Receives a notification of the occurrence of a failure in the transmission path from the failure occurrence / recovery detection unit 1, generates a failure notification cell generation control signal for each fixed-time timing signal sent from the timer unit 4, The control signal is periodically sent to the failure notification cell / recovery notification cell generation / insertion unit 2 at regular intervals.

The failure notification cell / recovery notification cell generation / insertion unit 2 generates a failure notification cell based on a failure notification cell generation control signal sent from the failure notification cell / recovery notification cell insertion instruction unit 3 at regular intervals. , Inserts the generated failure notification cell a into the transmission path and sends it to the alarm cell termination point B (step S in FIG. 3).
2).

Upon receiving the failure notification cell a from the alarm cell occurrence point A (step S11 in FIG. 4), the failure notification cell / recovery notification cell detector 6 at the alarm cell terminal point B receives the failure notification cell / recovery notification reception cell. The failure notification cell reception signal is transmitted to the insertion instruction unit 7.

Upon receiving the failure notification cell reception signal from the failure notification cell / recovery notification cell detection unit 6, the failure notification reception cell / recovery notification reception cell insertion instructing unit 7 receives the failure notification cell / recovery notification cell reception signal.
A failure notification reception cell generation control signal is sent to the recovery notification reception cell generation and insertion unit 8.

Upon receiving the failure notification receiving cell generation control signal from the failure notification receiving cell / recovery notification receiving cell insertion instructing unit 7, the failure notification receiving cell / recovery notification receiving cell generation / insertion unit 8 sets one failure notification receiving cell. Then, the failure notification receiving cell b is inserted into the transmission line and sent to the alarm cell occurrence point A (step S12 in FIG. 4).

When the failure notification receiving cell / recovery notification receiving cell detector 5 at the alarm cell occurrence point A receives the failure notification reception cell b sent from the alarm cell terminal point B (step S3 in FIG. 3), it receives the failure notification. The cell reception signal is sent to the failure notification cell / recovery notification cell insertion instruction unit 3.

Failure notification cell / recovery notification cell insertion instructing unit 3
When receiving the failure notification reception cell reception signal from the failure notification reception cell / recovery notification reception cell detection unit 5, the generation of the failure notification cell generation control signal is stopped, and the failure notification cell / recovery notification cell generation and failure for the insertion unit 2 are stopped. The transmission of the notification cell generation control signal is stopped.

The failure notification cell / recovery notification cell generation / insertion unit 2 receives the stop of the failure notification cell generation control signal from the failure notification cell / recovery notification cell insertion instruction unit 3 and generates the failure notification cell a and generates the failure notification cell. The insertion of a into the transmission path is stopped (step S4 in FIG. 3) [see FIG. 5 (a)].

On the other hand, when the failure occurrence / recovery detection unit 1 at the alarm cell occurrence point A detects the recovery of the failure in the transmission path (step S5 in FIG. 3), the failure transmission / recovery detection cell insertion instructing unit 3 transmits the failure notification cell / recovery notification cell insertion instruction unit 3. Notifies the recovery of the fault in the road.

Failure notification cell / recovery notification cell insertion instructing unit 3
Receives a notification of failure recovery from the failure occurrence / recovery detection unit 1, generates a recovery notification cell generation control signal for each fixed-time timing signal sent from the timer unit 4, and generates the recovery notification cell generation control signal. It is periodically sent to the failure notification cell / recovery notification cell generation / insertion unit 2 at regular intervals.

The failure notification cell / recovery notification cell generation / insertion unit 2 generates a recovery notification cell based on the recovery notification cell generation control signal sent from the failure notification cell / recovery notification cell insertion instructing unit 3 at regular intervals. , Inserts the generated recovery notification cell c into the transmission line and sends it to the alarm cell termination point B (step S in FIG. 3).
6).

The failure notification cell / recovery notification cell detector 6 at the alarm cell terminal point B receives the recovery notification cell c from the alarm cell occurrence point A.
Is received (step S14 in FIG. 4), the recovery notification cell reception signal is transmitted to the failure notification reception cell / recovery notification reception cell insertion instruction unit 7.

Upon receipt of the recovery notification cell reception signal from the failure notification cell / recovery notification cell detection unit 6, the failure notification reception cell / recovery notification reception cell insertion instructing unit 7 receives the failure notification reception cell / recovery notification cell reception signal.
A recovery notification reception cell generation control signal is sent to the recovery notification reception cell generation and insertion unit 8.

Upon receiving the recovery notification reception cell generation control signal from the failure notification reception cell / recovery notification reception cell insertion instructing unit 7, the failure notification reception cell / recovery notification reception cell generation / insertion unit 8 sets one recovery notification reception cell. Generated, the recovery notification receiving cell d is inserted into the transmission line, and sent to the alarm cell generation point A (step S15 in FIG. 4). Thereafter, the alarm cell terminal point B determines whether the processing is completed (step S13 in FIG. 4),
If the processing is completed, the processing is terminated. If the processing is not completed, the processing returns to step S11.

Upon receiving the recovery notification receiving cell d sent from the alarm cell termination point B (step S7 in FIG. 3), the failure notification receiving cell / recovery notification receiving cell detector 5 at the alarm cell occurrence point A receives the recovery notification. The cell reception signal is sent to the failure notification cell / recovery notification cell insertion instruction unit 3.

Failure notification cell / recovery notification cell insertion instructing unit 3
When the recovery notification receiving cell reception signal is received from the failure notification receiving cell / recovery notification receiving cell detection unit 5, the generation of the recovery notification cell generation control signal is stopped, and the failure notification cell / recovery notification cell generation and recovery notification to the insertion unit 2 are performed. The transmission of the cell generation control signal is stopped.

The failure notification cell / recovery notification cell generation and insertion unit 2 receives the suspension of the recovery notification cell generation control signal from the failure notification cell / recovery notification cell insertion instructing unit 3 and generates the recovery notification cell and generates the recovery notification cell. The insertion into the transmission path is stopped (step S8 in FIG. 3) [see FIG. 5 (b)]. Thereafter, the alarm cell occurrence point A determines whether or not the process is completed (step S9 in FIG. 3). If the process is completed, the process ends. If the process is not completed, the process returns to step S1.

FIG. 6 is a diagram showing an operation of generating an alarm cell when multiple failures occur according to one embodiment of the present invention. FIG. 6 (a)
6B shows the operation at the time of the occurrence of the preceding failure, FIG. 6B shows the operation at the time of the occurrence of the subsequent failure, FIG. 6C shows the operation at the time of recovery from the preceding failure, and FIG. Is shown. The operation of generating an alarm cell when multiple failures occur according to one embodiment of the present invention will be described with reference to FIG. The alarm cell occurrence point (first failure) A and the alarm cell occurrence point (late failure) C are configured as shown in FIG. 1 and operate as shown in FIG. The alarm cell terminal point B has the configuration shown in FIG. 2 and performs an operation as shown in FIG.

The alarm cell occurrence point (problem failure) A is provided with a failure notification cell (problem failure) e at a fixed interval with respect to the alarm cell termination point B when a advance failure occurs on the transmission line with the preceding node C. Occurs periodically.

Upon receiving the failure notification cell (advance failure) e, the alarm cell termination point B detects the occurrence of the failure, performs line blocking processing, and receives a failure notification for the alarm cell occurrence point (advance failure) A. A cell (first failure) f is generated. When the alarm cell occurrence point (first failure) A receives the failure notification reception cell (first failure) f, it stops generating the failure notification cell (first failure) e (see FIG. 6A).

The alarm cell occurrence point (later failure) C is a failure notification cell (late failure) for the alarm cell terminal point B if a later failure occurs on the transmission line with the preceding node during the occurrence of the first failure. g is generated periodically at regular intervals. At this time, the failure notification cell (late failure) g does not reach the alarm cell terminal point B because the first failure is occurring, so the failure cell is notified from the alarm cell terminal point B to the alarm cell occurrence point (late failure) C. Received cell (late failure) does not return. Therefore, at the alarm cell occurrence point (late failure) C, the failure notification cell (late failure) g
Are continuously generated at regular intervals [FIG.
(B)].

Thereafter, when the prior failure is recovered, the alarm cell occurrence point (first failure) A periodically generates a recovery notification cell (first failure) h at a constant interval with respect to the alarm cell end point B. Upon receiving the recovery notification cell (first failure) h, the alarm cell termination point B detects the recovery of the failure, releases the line blockage, and receives the recovery notification reception cell (first failure) for the alarm cell occurrence point (first failure) A. (First failure) i occurs. The alarm cell occurrence point (first failure) A is a recovery notification receiving cell (first failure) i
, The generation of the recovery notification cell (preceding failure) h is stopped [see FIG. 6 (c)].

In this case, since a subsequent failure is occurring, a failure notification cell (later failure) g in which an alarm cell occurrence point (late failure) C is periodically generated at regular intervals is an alarm termination point B. Reaches Upon receiving the failure notification cell (later failure) g, the alarm cell terminal point B detects the occurrence of the failure, performs the line blocking processing, and performs the alarm cell occurrence point (late failure) C
, A failure notification receiving cell (later failure) j is generated.
When the alarm cell occurrence point (late failure) C receives the failure notification reception cell (late failure) j, it stops generating the failure notification cell (late failure) g (see FIG. 6D).

As described above, the failure notification cells a, e, and g from the alarm cell occurrence points A and C generated at the time of occurrence of the failure are transmitted to the alarm cell termination point B and the failure notification from the alarm cell termination point B is received. The cells b, f, j are periodically transmitted until they are received, and the recovery notification cells c, h from the alarm cell generation point A generated at the time of failure recovery are transmitted to the alarm cell terminal point B.
By periodically transmitting the recovery notification receiving cells d and i from the alarm cell termination point B at regular intervals until the alarm notification cells are received, it is necessary to periodically generate the alarm cells at regular intervals while the alarm is occurring. , The band used by the alarm cell can be reduced. In addition, when an alarm cell is lost and multiple failures occur, the presence of a failure can be correctly transmitted to the alarm cell terminal point B.

[0065]

As described above, according to the present invention, the alarm cell generation system for notifying the end nodes of all the virtual paths accommodated in the transmission path and the path that the virtual path is unusable. In the above, when a failure is detected in any one of the transmission path and the path, the failure notification cell to the terminal node, until the failure notification reception cell from the terminal node indicating that the failure notification cell is received is received Transmit at a predetermined interval, and when the recovery from the failure is detected, notify the termination node of the recovery notification cell to the recovery notification reception cell from the termination node indicating that the recovery notification cell has been received. By transmitting the alarm at predetermined intervals until the alarm cell is received, the bandwidth used by the alarm cell can be reduced. There is an effect that can be transmitted correctly to the terminal node of the alarm cell.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an alarm cell generating node according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a terminal node of an alarm cell according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating an operation of an alarm cell generating node according to an embodiment of the present invention;

FIG. 4 is a flowchart illustrating an operation of a terminal node of an alarm cell according to an embodiment of the present invention;

5A is a diagram illustrating an operation of generating an alarm cell when a failure occurs according to an embodiment of the present invention, and FIG. 5B is a diagram illustrating an operation of generating an alarm cell during recovery from a failure according to an embodiment of the present invention. FIG.

6A is a diagram illustrating an operation of generating an alarm cell when a first failure occurs according to an embodiment of the present invention; FIG. 6B is a diagram illustrating an operation of generating an alarm cell when a second failure occurs according to one embodiment of the present invention; FIG. 3C is a diagram illustrating an operation of generating an alarm cell at the time of recovery from an advanced failure according to an embodiment of the present invention, and FIG. 4D is a diagram illustrating an operation of generating a subsequent alarm cell according to an embodiment of the present invention. It is.

7A is a diagram illustrating an operation when a failure occurs according to the conventional period generation method, FIG. 7B is a diagram illustrating an operation during a failure occurrence according to the conventional period generation method, and FIG. FIG. 6 is a diagram showing an operation at the time of failure recovery by the method.

FIG. 8A is a diagram showing an operation at the time of occurrence of a failure by the conventional change point notification method, and FIG. 8B is a diagram showing an operation at the time of failure recovery by the conventional change point notification method.

9A is a diagram showing an operation at the time of a prior failure occurrence by the conventional method of notifying a change point at the time of occurrence of multiple failures, and FIG. FIG. 3C is a diagram showing an operation at the time of recovery from a prior failure by a conventional method of notifying a change point when multiple failures occur.

[Description of Signs] 1 Failure occurrence / recovery detection unit 2 Failure notification cell / recovery notification cell generation / insertion unit 3 Failure notification cell / recovery notification cell insertion instruction unit 4 Timer unit 5 Failure notification reception cell / recovery notification reception cell detection unit 6 Failure notification cell / recovery notification cell detection unit 7 Failure notification reception cell / recovery notification reception cell insertion instruction unit 8 Failure notification reception cell / recovery notification reception cell generation and insertion unit A, C Alarm cell generation node B Alarm cell termination node a , E, g Failure notification cell b, f, j Failure notification reception cell c, h Recovery notification cell d, i Recovery notification reception cell

Claims (3)

[Claims] 1. An alarm cell generation system for notifying an end node of all virtual paths accommodated in a transmission path and a path by an alarm cell that the virtual path is unusable. Failure detection means for detecting a failure of a path and a path; and first transmission for transmitting a failure notification cell to the terminal node when the failure detection means detects a failure of any of the transmission path and the path. Means for controlling transmission of the failure notification cell from the first transmitting means at a predetermined constant interval until receiving a failure notification reception cell from the terminal node indicating that the failure notification cell has been received. A first control unit that performs recovery of the failure detected by the failure detection unit; and a recovery detection unit that detects recovery of the failure detected by the failure detection unit. Second transmitting means for transmitting the recovery notification cell to the terminal node when the recovery notification cell is issued, and the second transmission means until receiving the recovery notification reception cell from the terminal node indicating that the recovery notification cell has been received. And a second control means for controlling the transmission of the notification cell of the recovery at predetermined intervals from the transmission means of the alarm cell generation node. 2. The termination node, upon receiving the failure notification cell and detecting occurrence of the failure, sends back the failure notification reception cell to the generation node; and receiving the recovery notification cell. 2. The alarm cell generation system according to claim 1, further comprising: means for returning the recovery notification receiving cell to the generation node when the recovery from the failure is detected. 3. The first control means transmits the failure notification cell from the first transmission means at regular intervals until the failure detection means detects the failure and receives the failure notification reception cell. The second control means keeps the recovery notification cell from the second transmission means constant until the recovery detection means detects the recovery from the failure and receives the recovery notification reception cell. 2. The method according to claim 1, wherein the transmission is controlled so as to continue transmission at intervals.
Or an alarm cell generation system according to claim 2.