JPH06315023A - Backup path network designing method - Google Patents

Abstract

PURPOSE:To suppress a total backup path setting amount low by allocating a certain amount of paths, which are required for relieving a fault present path, to plural routes and defining a value integrating them as the initial value of the backup path setting amount. CONSTITUTION:Assuming the fault of a transmission line L1, first of all, a releif route R1 of a present path P11 housed in the line L1 is calculated. A relief route R2 provided with any backup path different from backup paths Y2 and Y4 constituting the route R1 is calculated. A number N11 (=1) of paths required for relieving the path P11 is integrated to the use amounts U12 and U16 of auxiliary paths Y2-Y6 on similarly calculated routes R1-R3. Next, assuming the fault of a transmission line L2, processing is similarly repeatedly performed up to a transmission line L6 afterwards. Next, a maximum value '2' of amounts U11-U61 to use a path Y1 for relieving the present path at the time of the fault in each transmission line is set to an initial value S1 for the amount of the path Y1 to be installed. Similarly, initial values S2-S6 are set, and the initial values of all the auxiliary path setting amounts are decided. Optimization is performed by deletion after started from this initial value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backup path network designing method for determining the installation amount of backup paths required for repairing a failed working path when a transmission line fails in a communication network.

[0002]

2. Description of the Related Art In a conventional backup path network designing method, the number of backup paths required for repairing a working path assuming a failure is assigned to a single route, and the accumulated value is used as a backup path installation amount. The initial value is set, and then the deletion is performed for optimization.

An example of the conventional method will be described below. Figure 5
Is a flow chart showing the procedure of the conventional backup path network designing method.
1 to 113 are processing steps, L _i is the i-th transmission path, P _ij is the j-th working path accommodated in the transmission path L _i , Y _k is the k-th backup path, and U _ik is The usage amount of the backup path Y _k at the time of failure of the transmission line L _i , N _ij indicates the number of repair paths of the working path P _ij , and S _k indicates the initial value of the installation amount of the backup path Y _k .

FIG. 4 is a diagram used to explain a backup path network designing method and shows an example of paths set between cross-connect devices. FIG. 4A shows an example of working paths and transmission paths. , (B) show examples of backup paths.

In the figure, reference numerals 1 to 4 are cross-connect devices, and L1 to L6 are L _i in FIG. 4 (i =
1 to 6), P11 to P61, Y1 to
The same applies to Y6 and the like.

FIG. 6 shows a case where the conventional backup path network designing method is applied to the communication network shown in FIG. 4, and the reference numerals in the figure are the same as those described above. A conventional backup path network designing method will be described below with reference to these drawings.

First, a failure of the transmission line L1 is assumed (processes 101 and 102). One relief route of the working path P11 accommodated in the transmission line L1 is calculated (process 103,
104).

At this time, the rescue route is set to an arbitrary route satisfying the conditions that "the starting point and the ending point are the same.""Do not pass the same path." In this example, the route 1-3-2
(Use of backup paths Y2 and Y4) (FIG. 6A).
Usage amount U12, U1 of the backup paths Y2, Y4 on the rescue route
4 The number of paths N11 (=
1) are piled up (process 105).

That is, U12 = U14 = 1. In this case, since the only working path accommodated in the transmission line L1 is P11, the process proceeds to the next process, and a failure of the transmission line L2 is assumed (processes 106, 108, 109, 102). Hereinafter, the same processing is repeated until the failure of the transmission line L6 (see FIG. 6).
(B)-(f)).

Next, the initial value S1 of the installation amount of the backup path Y1
Are the amounts U11, U21, U31, U41, U that use the backup path Y1 for repairing the working path when each transmission line fails.
51, the maximum value 2 of U61 is set (process 110, 1
11). Similarly, S2 to S6 are set (process 112, 1
13, 111), and the initial values of all backup path installation amounts are determined (FIG. 6 (g)).

Starting from this initial value, when optimization is performed by deletion, even if the number of backup paths Y1 (two) is reduced by one, each working path can be repaired for each transmission line failure. For example, even if L2 fails, 1 → 4 → 2 →
It can be relieved by the route of 3.

On the other hand, the backup path Y2 (one) is the transmission line L4.
It is necessary when there is a failure, etc., and the backup path Y3 (2) is 3 →
Since there is no backup path between 4 and 4, it is necessary when the transmission line L5 fails, and backup paths Y4 (two) are also required when there is a failure in the transmission line L2 because there is no backup path between 3 and 4, and the backup path Y4
Since 5 (1) is required when the transmission line L3 or the like fails,
The backup paths Y2 to Y6 cannot be deleted any more. Therefore,
The total number of backup paths installed is seven (FIG. 6 (h)).

[0013]

As described above, in the conventional backup path network designing method, the amount of paths required for repairing a failed working path is initially set to a single route in which the backup path is specified. Since it is assigned only to the specified route, the amount of backup paths installed after optimization by deletion tends to be biased toward a specific route.

That is, the optimization is performed on the premise of the path amount calculated as the initial value, and assigning a backup path to a specific single route at the time of calculating the initial value is performed when selecting a rescue route at the time of failure occurrence. This will limit the degree of freedom. Therefore, there is an unfavorable problem that the installation efficiency of the backup paths is deteriorated and, as a result, the total backup path installation amount is calculated to be large.

An object of the present invention is to provide a method of designing a backup path network that can increase the efficiency of installation of backup paths and keep the total backup path installation amount low.

[0016]

According to the present invention, the above-mentioned conventional problems can be solved by the means described in the claims.

That is, the present invention searches for a cross-connect device for switching the paths of a plurality of working paths and protection paths accommodated in a transmission path and a connectable protection path for repairing the working path of a failure transmission path. For a communication path having a network management device that determines a switching path, an initial value of the protection path installation amount is calculated, and then the deletion is performed to optimize the protection path. This is a backup path network design method in which a process of allocating an amount of paths necessary for repairing the working path to a plurality of routes in each case is performed for each transmission line, and a value obtained by accumulating them is used as an initial value of the backup path installation amount.

[0018]

According to the present invention, since the amount necessary for repairing the failure working path is allocated to a plurality of routes, even after the optimization by deletion, the failure working path is switched as compared with the case where it is allocated to a single route. The freedom of route search is increased,
Since it is possible to increase the degree of sharing of the backup paths used when each transmission line fails, it is possible to keep the total backup path installation amount low.

[0019]

1 and 2 are flow charts for explaining the procedure according to the present invention, in which n indicates the initial value of the backup path installation amount, which is set in advance. . Further, R _m indicates the m-th relief route. Other symbols and the like are the same as those described above. FIG. 3 is a diagram showing an embodiment of the present invention in the communication network shown in FIG. 4, in which an amount required for relief of a failure working path is allocated to four routes to calculate an initial value of a backup path installation amount (processing). 209 in the case where n is 4).

An embodiment of the present invention will be described below with reference to FIGS. 1, 2, 3, and 4. First, a failure of the transmission line L1 is assumed (processes 201 and 202). The rescue route R1 of the working path P11 accommodated in the transmission line L1 is calculated (processes 203 and 204). In this example, R1 is route 1-
3-2 (use the backup paths Y2 and Y4). A rescue route R2 configured to include a backup path different from the backup paths (Y2, Y4) configuring the repair route R1 is obtained (Process 20
5,206).

In this example, R2 is 1-4-2 (uses the backup paths Y3 and Y5). Similarly, the relief routes R1 and R
A repair route R3 including a backup path different from the backup path (Y2, Y3, Y4, Y5) forming 2 is obtained (processes 207, 209, 210, 206). In this example, R3 is 1-3-4-2 (using the backup paths Y2, Y6, Y5).

Next, since there is no repair path R4 including a backup path (Y2, Y3, Y4, Y5, Y6) different from the backup paths (Y2, Y3, Y4, Y5, Y6) forming the repair paths R1, R2, R3, it is obtained. Only three routes R1, R2, and R3 are available as repair routes (processing 207, 209, 210, 20).
6, 207, 208).

Backup path Y on rescue routes R1, R2 and R3
2, Y3, Y4, Y5, Y6 usage amount U12, U13,
The number of paths N11 (= 1) necessary for repairing the working path P11 is accumulated in U14, U15, and U16 (process 211).
That is, U12 = U13 = U14 = U15 = U16 = 1 (FIG. 3A).

In this case, since the only working path accommodated in the transmission line L1 is P11, the process proceeds to the next process, and a failure of the transmission line L2 is assumed (processes 212, 214, 215 and 215).
202). Thereafter, the same processing is repeated until the failure of the transmission line L6 (FIGS. 3B to 3F). Next, as the initial value S1 of the installation amount of the backup path Y1, the amounts U11 and U used to repair the working path at the time of failure of each transmission line are set.
The maximum value 2 of 21, U31, U41, U51, U61 is set (processing 216, 217).

Similarly, S2 to S6 are set (process 21
8, 219, 217), and the initial values of all backup path installation amounts are determined (FIG. 3 (g)). Starting from this initial value and performing optimization by deletion, for example, the backup path Y
1, Y3, Y4, and Y6 are reduced by one, and Y2 and Y5 are reduced by two (Y1 = Y3 = Y4 = Y6 = 1,
Y2 = Y5 = 0), the working path can be repaired for each transmission line failure.

However, the backup path Y1 (one) is the transmission line L.
It is necessary when 2, 2, L3, L4, L5, L6 fail, and the backup path Y3 (one) is the transmission lines L1, L2, L4, L5.
It is necessary when L6 fails, and the backup path Y4 (1 line) is necessary when transmission lines L1, L2, L3, L5, L6 fail, and the backup path Y6 (1 line) is transmission lines L1, L2.
The backup paths Y1 to Y6 cannot be deleted any more because they are needed when L3, L4, and L5 fail. Therefore, the total number of installed backup paths is four (FIG. 3 (h)).

In the present embodiment, the working path and the protection path are set between the adjacent cross-connect devices, and the model corresponding to the transmission path is used. However, the working path and the protection path configured via a plurality of transmission paths are used. The present invention can also be applied to paths. Further, it is applicable even when a line is used as a path. In addition, in the present embodiment, since only three relief paths can be set, there is no effect even if n is set to 3 or more, but generally, if the maximum number of relief paths can be set to A, optimization is performed as n approaches A with a number of A or less. Can be achieved.

[0028]

According to the present invention, the degree of freedom in searching for a switching route of a faulty working path is greater than that in the case where a single route is allocated, and it is possible to increase the sharability of a backup path used when each transmission line fails. There is. Further, as is clear from the description of the embodiment, there is an effect that the total backup path installation amount can be suppressed low.

[Brief description of drawings]

FIG. 1 is a flowchart (No. 1) showing an example of a procedure for designing a backup path network according to the present invention.

FIG. 2 is a flowchart (No. 2) showing an example of a procedure for designing a backup path network according to the present invention.

FIG. 3 is a diagram showing an embodiment of the present invention.

FIG. 4 is a diagram for explaining a backup path network designing method.

FIG. 5 is a flowchart showing a procedure of a conventional backup path network designing method.

6 is a diagram showing an example in which a conventional backup path network designing method is applied to the communication network in FIG.

[Explanation of symbols]

1-4 cross-connect device 101～113,201～219 process L _i (L1~L6) _i th transmission path P _ij (P11~P61) j th working path accommodated in the transmission path L _i Y _k ( Y1 to Y6) k-th protection path U _ik (U11~U66) transmission path L usage N _ij (N11~N61 of _i failure time backup path Y _k) of relief pass number S _k of the working path P _ij (S1 to S6) Initial value of installation amount of backup path Y _k n Initial value of backup path installation amount

Claims (1)

[Claims] 1. A cross-connect device for switching a plurality of working paths and protection paths accommodated in a transmission path, and a spare path connectable to repair a working path of a failed transmission path, and a switching path is determined. In a backup path network design method that calculates the initial value of the backup path installation amount for a communication network having a network management device that performs A backup path network designing method characterized in that a process of allocating a required amount of paths to a plurality of routes is performed for each transmission line, and a value obtained by accumulating them is used as an initial value of a backup path installation amount.