JP3374521B2 - Detour design method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of designing a detour for switching a plurality of working lines having different grounds to protection lines when switching networks when a large bundle transmission line fails.

[0002]

2. Description of the Related Art A conventional digital transmission line network switching system (D
As for the detour route search method in SW, the shortest route method is repeatedly used to increase the number of rescue lines, and a detour route is searched for in advance assuming a failure. In the case of an unexpected failure, the detour route is searched immediately by the shortest route method on a line-by-line basis according to the failure situation.

FIG. 2 is an explanatory diagram showing an example of a network configuration and an amount of setting of a protection line. Switching node stations (hereinafter referred to as nodes) A to H are mutually connected by a transmission line. That is, the network is composed of a transmission line that transmits multiplexed signals and nodes A to H that are connection points of this transmission line. Each of the nodes A to H is provided with a module (switching module) having a cross-connect function for distributing signals multiplexed in the digital area. This network can be switched to a predetermined transmission path by sending a transmission path switching command from the control device to the switching module.

In FIG. 2, nodes A to H are connected by a transmission line, and each node and the control device transmit and receive information through an information transfer network. In FIG. 2, the working line that extends along the path from "node A" to "node D" is called the "working path", and usually the shortest path connecting the start node (node A) and the end node (node D) This is called the "shortest link".) And the working path is set.

On the other hand, a path for bypassing the working path due to a failure or transfer of a transmission line is called a backup path, and a predetermined number of lines are provided between adjacent nodes (for example, node A and node B).

[0006] Conventionally, in the detour design of such a transmission line network, a failure section is assumed in advance, an optimum detour route that can be detoured by the shortest link is calculated and registered in a database.

[0007]

SUMMARY OF THE INVENTION The successive improvement method, which is a method of searching for a detour route in a conventional digital transmission network switching system (DSW), requires a long time for searching a detour route,
Even in the case of an unexpected failure, there is a drawback that it takes time because it is performed immediately by a simple method using the shortest path method, and there is a high risk of interruption to the ground because the survival rate to ground is not taken into consideration. It is not always possible to efficiently use the protection line. Therefore, there has been a long-felt demand for a detour design method that can shorten the time required for an unexpected failure and can efficiently use a spare.

In the conventional detour route calculation method, first, the detour route is found for the working path "a", the backup path is allocated, and then the detour route is found for the working path "i" and the backup path is distributed. Since it is designed in a proper manner, there are cases where a working path for which a backup path cannot be set or a shortest link cannot be set.

Further, since the number of allocated lines differs depending on the order in which the working paths are calculated, the order of the working lines is exchanged, and the optimum detour route is selected from the designs for all combinations. There was a problem that it took time to design the route.

Further, since it is necessary to register the optimal detour route information as a database for each assumed failure section, there is a problem that the database becomes huge. Further, the transmission line changes every day due to trouble transfer or the like, and therefore, the optimum detour route design needs to be redone at the time of the change.

The present invention has been made in view of the above circumstances, and a detour route is designed so that there is no working path for which a backup path cannot be set, and an optimal detour route is designed in real time by high-speed design processing. The purpose is to provide a method for designing a road.

[0012]

In order to achieve the above object, the present invention is a method for designing a detour for switching a plurality of working lines having different grounds to a protection line, and a method for connecting a working line to a protection line. A search step for searching a different detour route, a calculation step for calculating the number of working lines scheduled for switching aiming at the protection line of the detour route obtained in the searching step, and the number of working lines scheduled for switching is the number of the protection lines. If the number exceeds the above-mentioned working line, it comprises a allocating step for allocating the protection line based on the number of the working lines, and a allocating step for allocating the working line to be switched to the protection line allocated in the allocating step. It is a thing.

Further, in the allocating step, when the number of working lines to be switched exceeds the number of protection lines, the protection lines are proportionally distributed by the number of working lines, and the working lines to be switched are When the number is smaller than the number of the protection lines, the protection lines are distributed by the number of the working lines.

[0014]

According to the present invention, when the working paths aiming at the protection paths are contended, the invention is proportionally distributed according to the number of lines of the working paths, so that the protection paths are allocated to more working paths. You can

Even if all the working paths cannot be allocated in the first detour route design, it is sufficient to redesign the detour route only for the unrepaired working path, which is shorter than the conventional design method. The optimum detour route can be designed in real time even if immediate processing such as a failure is required.

Further, since the detour route is designed at the time when switching is required, it is possible to provide the detour route suitable for the current network. In addition, since it is not necessary to register a huge amount of optimum detour route data in the memory in advance, the amount of information stored in the memory can be reduced, and a high-speed, small-capacity storage device can be used instead of a large-capacity storage device such as a hard disk. Memory can be used.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 is an explanatory diagram showing an exemplary network configuration and a setting amount of a protection line for explaining the method of the present invention, and FIG. 3 is an explanatory diagram showing an example of a working line accommodated in a failure transmission line. . In addition, according to the present invention, it is possible to perform switching in a more complicated network. Consider a case where the transmission path between the node B and the node C fails in the network configuration shown in FIG. Node B to node C
The working line “A” (node A to
10 working lines (between C), “I” (between nodes B and D)
5 working lines and one working line of "U" (between nodes A to D) are accommodated, "a",
The first detour design is performed for each of the "i" and "u" line groups.

In this case, the processing is not performed for each line (16 times in the example of FIG. 3), but for each line group (3 times in the example of FIG. 3).
Times). Figure 4 shows line end switching and detour design (first time)
It is an explanatory view showing an example of the latter state, but the present invention does not limit the detour design method. as a result,
The "A" detour route is between A to E to F to C (hereinafter referred to as "A '"), and eight reliefs are possible. The "I" detour route is between B to E to F to D (hereinafter "A"). It is designed such that four lines can be repaired, and the detour route of "U" is between A to E to F to D (hereinafter referred to as "U"), and one can be repaired.

Paying attention to these working lines and the amount of spares, when the number of working lines aiming for the spare is larger than the amount of spares, it is distributed in proportion to the number of the working lines aiming for the spare. If the number of working lines aiming for a spare is less than the spare amount, allocation is unnecessary.
A new switching network is assumed by tracing the working line after allocation along the detour route and subtracting from the unallocated reserve amount. This process is shown in the distribution process in Figure 5,
It is explanatory drawing which shows an example of the number of working lines which can be repaired, and an unused spare number.

On the other hand, as shown in FIG. 6, since the number of working lines accommodated in the faulty transmission line is also relieved by the first design, only the unrestored working lines are taken as the working ones.
Assume a new switching network.

The switching network assumed here can enter a detour design as a new switching network without being aware of the switching history up to now. As a result of performing the second detour design, all the unrelieved working lines have been relieved, and thus the detour design work is completed.

FIG. 7 is an explanatory view showing an example of the state after the network configuration, the set amount of the protection line, the line end switching, and the detour design (second time). “A” and “I” in FIG. 6 are the failed working paths (paths that could not be relieved in the first design),
“A ′” and “I ′” in FIG. 7 are bypass routes (second design) of “A” and “I” in FIG. 6.

In a switching network more complicated than that of FIG. 2, the design is repeated for the third time and the fourth time, and the detour design work is finished when the unrepaired working line is lost or the detour cannot be designed. become. In a switching network with a large amount of spares, all working lines can be repaired by the first detour design, so the detour design time can be shortened.

The memory of the control device which transmits and receives information to and from the nodes A to H through the information transfer network stores the transmission path information and the working path information shown in FIG. 8A. The transmission path information of FIG. 8A is created for each transmission path between the nodes A to H, and the working / spare data, the start point node / end point node numbers, and the like are written therein.

In the working path information of FIG. 8B, the path name, the path of the working path, and the number of working lines are written for each path. First, when a failure occurs in the working path, an alarm is sent from the corresponding node to the control device. The control device identifies the corresponding transmission line from the transmission line information based on the node number included in the alarm. In FIG. 2, it is understood that a failure has occurred in the section BC from the start point node B and the end point node C included in the alarm.

FIG. 1 is a flow chart showing the design process of the present invention. The detour route designing method of the present invention will be described below with reference to the flowchart. In step [1], information registered as "spare" is extracted from the transmission path information to create spare path information. (The number of usable backup paths is calculated for each ground.) In step [2], the working path including the failure section BC is acquired from the working path information for each path ground and the switching target path information is created. (The number of paths to be switched is calculated for each ground.) In step [3], the shortest link route is obtained by the shortest route method for the first record (current path “A”) of the switching target path information, and the detour routes AE -F
-C is selected. (One route is searched for one ground.) In step [4], the number of backup lines (AE is 8) in each section (AE, EF, FC) of the "detour route AEFFC"
The number of spare lines (ie, 8) that can be secured in the detour route is calculated from the number of lines, EF of 10 lines, and FC of 8 lines, and is written in the “number of detouring working lines” (see FIG. 5) of the work data in FIG. . Next, the steps [3] and [4] are similarly executed for the working paths "i" and "u", and the detour route "B" is executed.
-E-F-D "and" A-E-F-D ", the number of protection lines (4 and 1) that can be secured is written in the" number of detouring working lines "of the work data of FIG. (Check the number of relievable paths in the acquired route.) In step [5], steps [3] and [4] are performed until all detour searches are completed.
repeat.

In steps [6] to [8], the degree of competition is calculated in order from the first record of the work data.
More specifically, the number of lines targeted by each working path in each section (in the section AE, there are eight working paths “a ′”,
If there is one "U '" (9 in total) and the number of backup lines is 8 (number of backup lines / total working paths targeted), the contention level is less than 1. , The number of protection lines is proportionally distributed by the number of working paths. If the competition is 1 or more, the number of active paths is written.

In step [9], steps [6] to [8] are repeated until the confirmation of the competitiveness of the backup path is completed for all the ground points. In step [10], the number of working lines after allocation is 7 for the section AE when the working path is "a '".
There are 6 lines, 6 sections EF, and 8 sections CF, and a minimum value of 6 sets a repairable working line.

In step [11], step [10]
The number of recovery paths calculated in step S1 is subtracted from the number of backup paths to update the number of backup paths in the work data. In step [12], it is determined whether or not all the switching target paths are 0, and if not 0, the process returns to step [3] and the above-described design is performed.

The work data of FIG. 10 is the second design, and is obtained by the design process of the flowchart shown in FIG. 1 in the same manner as the first design of the work data of FIG. As described above, since the working line having only one line between the nodes can be repaired, it is possible to avoid the communication interruption.
Since the detour design is performed on a line group basis, there is an advantage that the detour design can be processed at high speed.

[0031]

As described above, according to the present invention, a detour route is designed so as to allocate a backup path to a larger number of working paths, and a detour route for designing an optimum detour route in real time by high-speed design processing. A method of designing a road can be provided.

[Brief description of drawings]

FIG. 1 is a flowchart showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a network configuration and a setting amount of a protection line.

FIG. 3 is an explanatory diagram showing an example of a working line accommodated in a faulty transmission line.

FIG. 4 is an explanatory diagram showing an example of line end switching and detour design (first time).

FIG. 5 is an explanatory diagram showing an example of a distribution process, a repairable working line number, and an unused spare number.

FIG. 6 is an explanatory diagram showing an example of the number of unrepaired working lines accommodated in the faulty transmission line.

FIG. 7 is an explanatory diagram showing an example of a network configuration, a setting amount of a protection line, line end switching, and detour design (second time).

FIG. 8 is an explanatory diagram showing an example of transmission path information and working path information according to the present invention.

FIG. 9 is an explanatory diagram showing an example of work data (first design) according to the present invention.

FIG. 10: Work data according to the present invention (second design)
It is explanatory drawing which shows an example.

[Explanation of symbols]

A to H ... nodes, ah, u ... faulty working path,
A ', I', U '... A, I, U detour route.

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yukio Yamagishi 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (72) Inventor Hiromichi Ito 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Within Nippon Telegraph and Telephone Corporation (56) Reference JP-A-5-48604 (JP, A) JP-A-4-263540 (JP, A) JP-A-2-43850 (JP, A) JP-A-60-218956 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04L 12/56 100

Claims (2)

(57) [Claims] 1. A method for designing a detour for switching a plurality of working lines with different grounds to a protection line, the method comprising: a search step for searching a detour route different from the connection path of the working line in the protection line; A step of calculating the number of working lines planned for switching aiming at the protection line of the bypass route, and if the number of working lines planned for switching exceeds the number of protection lines, based on the number of working lines A detour route designing method comprising: an allocation step of allocating the protection line; and an allocation step of allocating a working line to be switched to the protection line allocated in the allocation step. 2. The allocating step, when the number of working lines to be switched exceeds the number of the protection lines, proportionally distributes the protection lines by the number of the working lines to change the working lines to be switched. 2. The detour route designing method according to claim 1, wherein when the number is less than the number of the protection lines, the protection lines are distributed by the number of the working lines.