JPH1155272A - Atm communication network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a preliminary route in flexible accordance with the fluctuation of traffic and the change of the situation by periodically re-retrieving band information on the preliminary route which is previously set and resetting the preliminary route. SOLUTION: An ATM communication network is provided with an operation (OpS) system 10 as a means for setting a virtual preliminary route 2 used when the route cannot transfer information for a present route 1 between a transmission node N1 and a reception node N4. The OpS system 10 tentatively sets the preliminary route at every constant period. Since the preliminary route 2 which is set is not fixed but it is used by the other present route, band information is periodically retrieved on the preliminary route and it is reset. Band information is collected by the data base of the OpS system 10 and therefore the situation of the band can be detected by retrieval.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ATM (Asynchronou).
s Transfer Mode: Used for communication.
In particular, the present invention relates to a technique for setting a backup route to be used when an active route fails.

[0002]

2. Description of the Related Art For a failure of a node or a transmission line in an ATM communication network, a rerouting is set beforehand or at the time of failure by searching for a spare route. For example,
THWu "Fiber Network Service Survivability", Artech
House, (1992).

[0005] The setting of the working and backup routes of the conventional ATM communication network will be described with reference to FIGS. 10 and 11. FIG. 10 is a diagram for explaining a conventional detour process of a failure point in which a backup route for a working route is always set. FIG. 11 is a diagram for explaining a conventional detouring process of a failure point in which a spare route is set after a failure occurs.

[0004] In the detour processing of a failure point shown in FIG. 10, when a working route is set, a backup route (a detour route) is set. This backup route secures a fixed and same bandwidth as the working route. In the example shown in FIG. 10, 10Mb / s
A backup route 2 of b / s is set in advance, and the transmission node N1 has the table T. However, in order to use the band effectively, the spare route 2 is devised to be shared with another spare route. The operation system (shown as an OpS system) 10 grasps band information of a route that passes through each node, and performs overall setting of a working route and a backup route.

[0005] In the detour processing of a failure point shown in FIG. 11, a cell called a flooding cell is transmitted from a receiving node N4 to all connected nodes N6, N3 and N8. Each node N6, N3, N8 copies its flooding cell, and further, each node N6, N3, N8
To the node connected to. Such a transfer process is repeated, and a route in which a flooding cell arrives at the transmission node N1 and has an empty capacity of 10 Mb / s or more is set as a backup route.

The technique of setting a backup route in accordance with the arriving flooding cell at the transmitting node N1 is a known technique, and therefore detailed description is omitted. Each time the signal passes through a node, the identification code of the node is transferred while being written in the cell. The transmitting node N1 that has received the flooding cell refers to the identification code, recognizes the route that the flooding cell has passed, and sets the route as a backup route.

According to the conventional example shown in FIG. 11, each node can autonomously set the working and backup routes without providing the operation system 10 unlike the conventional example shown in FIG. Further, since the route is selected and set by actually transferring the flooding cell, the shortest optimal route can be easily selected and set.

[0008] By employing such a detour processing of a failure point shown in FIGS. 10 and 11, a highly reliable ATM communication network that can use a backup route when a failure occurs in the working route is realized. be able to.

[0009]

However, in the detour processing of the fault location shown in FIG. 10, since the backup route is fixedly set in advance when the working route is set, for example, the traffic amount and the situation of the ATM communication network are changed. This reserve route cannot be changed even if is changed. For this reason, a route may occur in which the traffic is partially biased, or the working route cannot be used due to the backup route. In addition, in the detour processing of a failure point shown in FIG. 11, since a spare route is selected and set after a failure occurs, it takes a long time until recovery, and a situation occurs in which communication is interrupted.

The present invention has been made in such a background, and provides an ATM communication network capable of setting a spare route flexibly in response to traffic fluctuations and changes in network conditions. With the goal. SUMMARY OF THE INVENTION It is an object of the present invention to provide an ATM communication network having a short communication interruption time when a failure occurs.

[0011]

The most important feature of the present invention is that a spare route is set in advance, but the bandwidth information of the spare route is re-searched periodically and / or the spare route is reset.

The difference from the prior art is that the active route may use the backup route, and that the bandwidth information of the backup route is periodically searched and / or the backup route is reset.

That is, the present invention relates to an ATM communication network, wherein a spare cell transfer route used between a transmitting node and a receiving node when a current cell transfer route cannot be transferred is used. AT with means for setting
M communication network. A feature of the present invention resides in that the setting means includes means for experimentally setting a spare route at regular intervals.

That is, according to the present invention, a route set as a protection route of a certain working route is permitted to be used by another working route, so that the band of the protection route is occupied by another working route. May be disconnected. Therefore, by setting a backup route on a trial basis at regular intervals, the setting of the backup route whose bandwidth is occupied by such other working routes can be canceled, and a new backup route can be set. Further, by setting the backup route on a trial basis at regular intervals, it is possible to realize the setting of the backup route adapted to the situation of the network that changes every moment.

The means for experimentally setting may include means for selecting and setting another route as a spare route when the scheduled spare route is interrupted. That is, as described above, the backup route may be reset periodically regardless of the bandwidth of the backup route already set, but the bandwidth information of the backup route already set is detected. Alternatively, another route may be newly selected and set as a spare route only when the bandwidth of the spare route is insufficient.

The setting means includes means for periodically transmitting a spare route setting cell from a receiving node to a plurality of routes, and setting a route in which the cell arrives at the transmitting node as a spare route. Means.

That is, the receiving node causes a plurality of routes to transmit spare route setting cells. Since the cell that has passed through the shortest route at that time arrives at the transmitting node first, the path of the cell that has arrived at the transmitting node first is set as a spare route, so that the network at that time is set. In such a situation, it is possible to easily select and set the optimal route which is the shortest.

[0018]

Embodiments of the present invention will be described with reference to FIG. FIG. 1 is a diagram for explaining the detour processing of a failure point according to the first embodiment of the present invention.

The present invention relates to an ATM communication network as means for setting a spare route 2 to be used between a transmitting node N1 and a receiving node N4 when the route becomes untransferable with respect to a working route 1. Is an ATM communication network provided with an operation system (shown as an OpS system) 10 of FIG.

Here, the feature of the present invention resides in that the operation system 10 experimentally sets a backup route at regular intervals.

[0021]

【Example】

(First Embodiment) A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 to FIG. 3 are diagrams for explaining a detouring process of a failure point according to the first embodiment of the present invention. FIG. 4 is a flow chart showing the detour processing of the fault location according to the first embodiment of the present invention. As shown in FIG. 1, a backup route 2 is reserved for a working route 1. However, the backup route 2 is not fixed and may be used by another working route or the like. Therefore, the bandwidth information of the backup route is periodically searched and reset.

As shown in FIG. 2, when the protection route 2 is used by another working route, the band is occupied by the other working route, so that the band for the protection route 2 is insufficient. Or disappear. Since the bandwidth information of the route passing through each node is collected in the database of the operation system 10 shown in FIG. 1, it is necessary to search the database to check the bandwidth status without actually transferring the cells. Can be detected. Therefore, in the first embodiment of the present invention, the bandwidth information of the backup route 2 is periodically searched, and if a shortage of the bandwidth of the backup route 2 is detected at that time, a new backup route is reset. The operation system 10 knows all the used routes and the band information of each node in the network, and performs the setting of the working and backup routes in an integrated manner.

The search and resetting of the band information of the spare route is an event within the time Pt. When the time Pt has elapsed, it is searched whether or not the reserved route 2 virtually planned has already been used by another working route, and if it has been used, as shown in FIG. Resets another spare route 3.

As described above, the backup route is not fixed, and the other working routes can use the virtual backup route as if it were an empty route, so that the entire network can be used flexibly. Do not create a spare route that could cause a bottleneck.

That is, as shown in FIG. 4, the operation system 10 monitors the timing (S1).
When the time Pt has elapsed since the search or reset of the bandwidth information of the previous backup route and the search time has come (S2), the database of the operation system 10 is searched to detect the bandwidth of the currently set backup route ( S3). If the bandwidth is not secured in the backup route (S4), a new backup route is reset (S5). Here, the time Pt
May be set to an optimal value according to the state of the network. In the first embodiment of the present invention, the time Pt is set to 10 seconds.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a diagram for explaining a detouring process of a failure point according to the second embodiment of the present invention. The second embodiment of the present invention is an embodiment in which the setting of the backup route by the flooding cell described in FIG. 11 of the conventional example is performed for the setting of the backup route of the first embodiment of the present invention.

That is, in the second embodiment of the present invention, similarly to the first embodiment of the present invention, an operation system 10 is provided and performs processing according to the flowchart shown in FIG. In resetting a new backup route (S5), a backup route is reset using the flooding cell described in FIG. 11 of the conventional example. The operation system 10 sends a flooding cell from the receiving node N4, detects the arrival of a fluttering cell at the transmitting node N1, and sets a backup route according to the route information written in the flooding cell.

According to the second embodiment of the present invention, as described in the first embodiment of the present invention, the result of actually transferring the flooding cell regardless of the band information collected by the operation system 10 is obtained. Therefore, since the backup route is set, it is possible to easily select and set the optimal backup route which is the shortest in the state of the network at that time.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a flowchart showing the bypass processing of the fault location according to the third embodiment of the present invention. The third embodiment of the present invention is an embodiment in which the band detection of the backup route performed in the first and second embodiments of the present invention is not performed. That is, the backup route is periodically reset regardless of the bandwidth of the backup route already set. As a result, even if the bandwidth of the backup route is not occupied by other working routes, a new backup route adapted to the situation of the network that changes every moment can be set. , It is possible to set an optimal backup route that is the shortest.

As shown in FIG. 6, the operation system 10 monitors the timing (S7), and when the time Pt has elapsed since the previous resetting of the backup route and the resetting time has come (S8), the operation system 10 has already been set. Regardless of the bandwidth of the backup route, a new backup route is reset (S9).

In setting the backup route, the backup route may be set based on the bandwidth information grasped by the operation system 10 as described in the first embodiment of the present invention, or the backup route may be set in the second embodiment of the present invention. As described in the example, a backup route may be set by using a flooding cell.

(Fourth Embodiment) A fourth embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a diagram for explaining a detour processing of a failure point according to the fourth embodiment of the present invention. FIG.
FIG. 14 is a flowchart showing a bypass process of a failure point in the receiving node according to the fourth embodiment of the present invention. FIG. 9 is a flowchart showing a bypass processing of a failure point in the transmitting node according to the fourth embodiment of the present invention. The fourth embodiment of the present invention, like the third embodiment of the present invention, is an embodiment in which the backup route is periodically reset regardless of the bandwidth of the backup route already set. However, in the fourth embodiment of the present invention, FIG.
As shown in (1), each node can autonomously perform processing without installing the operation system 10 in the network.

As shown in FIG. 8, at the receiving node N4, the timing is monitored (S10), and when the time Pt has elapsed since the previous resetting of the backup route and the resetting time has come (S1).
1), nodes N6 and N connected to the receiving node N4
3. Transmit a flooding cell to N8 (S1
2). Each node N6, N3, N8 copies the flooding cell and sends it to the nodes connected to each node N6, N3, N8. While repeating such a transfer process, the flooding cell eventually arrives at the transmitting node N1.

As shown in FIG. 9, the transmitting node N1 monitors the arrival of the flooding cell (S13), and if there is any arriving flooding cell, a new backup route according to the passing route information recorded in that cell. Is reset (S15). When a plurality of flooding cells arrive at the transmission note N1, a new backup route is reset according to the passage route information recorded in the first arrived flooding cell.

As described above, in the fourth embodiment of the present invention, the backup route is periodically reset regardless of the bandwidth of the backup route that has already been set. At that point, an optimal backup route can be set. In particular, by using a flooding cell, the shortest backup route at that time can be easily selected and set.

[0036]

As described above, according to the present invention,
A backup route can be set flexibly in response to changes in traffic and changes in network conditions. Further, the interruption time of communication when a failure occurs can be shortened.

[Brief description of the drawings]

FIG. 1 is a view for explaining a detour process of a failure location according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a detour processing of a failure point according to the first embodiment of the present invention.

FIG. 3 is a view for explaining a detour process of a failure point according to the first embodiment of the present invention.

FIG. 4 is a flowchart showing a detour processing of a failure point according to the first embodiment of the present invention.

FIG. 5 is a view for explaining a detour processing of a failure point according to the second embodiment of the present invention.

FIG. 6 is a flowchart illustrating a detour processing of a failure point according to the third embodiment of the present invention.

FIG. 7 is a view for explaining a detour processing of a failure point according to a fourth embodiment of the present invention.

FIG. 8 is a flowchart illustrating a process of bypassing a failure point in a receiving node according to a fourth embodiment of the present invention.

FIG. 9 is a flowchart illustrating a process of bypassing a failure point in a transmission node according to a fourth embodiment of the present invention.

FIG. 10 is a diagram for explaining a conventional detouring process of a failure point in which a backup route for the working route is always set.

FIG. 11 is a view for explaining a conventional detour processing of a failure point for setting a backup route after a failure has occurred.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Working route 2, 3 Spare route 10 Operation system N1-N8 Node T Table

Claims (3)

[Claims] 1. An ATM communication network comprising: means for setting a spare cell transfer route to be used when a current cell transfer route becomes untransferable between a transmitting node and a receiving node when the route cannot be transferred. The ATM communication network according to claim 1, wherein said setting means includes means for experimentally setting a spare route at regular intervals. 2. The AT according to claim 1, wherein said test setting means includes means for selecting and setting another route as a backup route when the scheduled backup route is interrupted.
M communication network. 3. The setting means includes means for periodically transmitting a spare route setting cell from a receiving node to a plurality of routes, and using a route in which the cell arrives at the transmitting node as a spare route. 2. The ATM communication network according to claim 1, further comprising a setting unit.