JP2684570B2 - Core switching system for communication network failure recovery - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a failure recovery core wire switching system for a communication network for early communication recovery when a cable fails in the communication network.

[Prior Art] There is no detour route for the cable in the conventional subscriber network, and in order to relieve a subscriber who has lost communication when the cable fails, the emergency recovery cable is transported to the failure point and a failure occurs. Cable failure recovery is performed by switching the cable cores one by one. However, this method requires a large number of workers and work time for transporting the recovery cable and laying the recovery cable, and thus the time from the occurrence of a failure to the recovery becomes enormous.

Therefore, instead of using an emergency recovery cable, a method of laying the cable in a ring beforehand and switching the core wire affected by the failure to a spare core wire in the cable that does not pass through the failure point of the same cable when the cable fails is considered. There is. If this method is used, all the subscribers affected by the failure will be restored by switching the core wire at the point where all the subscribers affected by the failure are connected to the loop line when the cable failure is restored. You can

However, if the number of subscribers existing in the loop line or the number of connection points between the loop line and the subscriber increases, the number of switching cores at the time of cable failure recovery increases, so if the number of workers is limited, the recovery work time Will increase. In addition, in order to recover all subscribers affected by the failure by using this method, keep the same number of spare cores as the cores in use between each subscriber of the loop line and the station. Since the cable must be used, the efficiency of using the cable core wire is 50% at maximum.

Also, conventionally, when a cable fails, a switching connection device is installed at a point that intersects with the annular cable, that is, a switching connection point,
Although it was not considered to recover from a failure,
FIG. 9 shows a configuration diagram of a recovery system when this switching connection device is applied to the above-described conventional recovery system.

FIG. 9 (1) shows a configuration diagram of the annular cable,
(2) Fig. 2 shows an example of switching connection of a switching connection device provided at a point intersecting with the annular cable. In FIG. 9 (1), reference numeral 1 is a telephone station, 11, 12, 14 are switching connection devices provided at switching connection points, and 21-23, 31-33 are links. And
(2) In the case of the figure, the number of cores of each link 21, 22, 31, 32 is N, and when the link does not fail, the core of the link 21 is connected to the core of the link 22, and The core wire of 31 is connected to the core wire of the link 32. Then, for example, when one core wire in the link 21 fails, all the other core wires can be connected and detoured. In this way, when there are a plurality of detours, the switching connection devices 11, 12, and 14 between the loop lines that allow the detours to be arbitrarily selected can be connected to all the cores by a complete line group configuration (1 It is necessary to have a switching function with a configuration that allows mutual connection with each other.

In the case of this complete line group configuration, each switching connection device 1
The number of switching connections in 1,12,14 can be expressed as follows.

Number of switching connections = 1/2 × 4N (4N-1) = 2N (4N-1) (1) In addition, N is the number of cable core wires which form a loop line, and includes a spare core wire. In the method of switching the core wires one by one when a cable fails, the number of switching connections in each switching connection device installed at each switching connection point is proportional to N ² as shown in equation (1). As the number of cores in the line increases, the size of each switching connection device increases and has a complicated structure, and switching work time increases at the time of recovery from a failure.

[Problems to be Solved by the Invention] In the above-described conventional restoration system, when the number of subscribers existing in the loop line or the number of connection points between the loop line and the subscriber increases, the number of core wire switches at the time of cable failure recovery increases. Therefore, there is a problem that it takes a long time to switch the core wire and the recovery work time increases.

[Means for Solving the Problem] In order to solve such a problem, the communication network failure recovery core wire switching system according to the present invention includes H wires (1 <H ≦ M) connected to a switching connection point. When any one of the cables fails, the H cables provided in the switching connection point are connected to each other by a specific number k of cores (1 <k ≦
The present invention is provided with a switching connection device having a plurality of switching contacts for changing the connection in the N) unit core group.

[Operation] When a cable fails, the number of core wires used in the defective cable is set to 1 at the core wire switching point between the switching connection points sandwiching the failure cable.
After switching to the spare core wire in units of cores and diverting the subscriber to the switching connection point, from the switching connection point to the central office, at least one of the used core wire group and the spare core wire group in the faulty cable is switched by the switching connection device. Switch and connect to the spare core group on a wire group basis.

Example Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a switching connection function showing an embodiment of a core switching system for failure recovery of a communication network of the present invention. In the figure, parts that are the same as the block diagram of the recovery system in FIG. 9 are given the same reference numerals, and descriptions thereof are omitted. In FIG. 1, 41 to 43, 51 to 53 are used core groups, R1 to R4 are spare core groups, J is a switching core group, and C is a switching contact. And
In this configuration example, it is composed of seven switching contacts C,
When a cable failure occurs, the switching core group J is connected to these switching contacts C to change the connection.

Next, FIG. 2 is a network model diagram for explaining the installation positions of the switching connection devices 11-14. The circles in the figure are subscribers. According to this figure, telephone station (hereinafter referred to as station)
The cable core wires extend from 1 to 8 directions, and two of them are set as one set to form four annular lines. Also,
As shown in FIG. 2, the number of core wires in use between the station 1 and each switching connection point or between each switching connection point along the loop line is equal so that the number of core wires in use is the same. 4 switching connection devices for each of the 4 switching connection points for connection
11-14 are installed.

Here, a bundle of cords accommodating subscribers existing along the loop line between the station 1 and each switching connection device or between each switching connection device is referred to as a cord group.

Further, the same number of spare core wires as the number of core wires of the core wire group are laid along the loop line is called spare core wire groups R1 to R4.

Further, in order to switch the failed core wires to the spare core wires one by one when the cable fails, it is necessary to switch at the connection point between the loop line and each subscriber. The subscriber between the loop lines can use the spare core wire accommodated in the cable of the loop line, so that the core wire can be switched at the place where each subscriber exists. Such a place is called a core switching point.

Next, the network model diagram of FIG. 2 will be described in more detail. First, if the cable of an arbitrary link (between the station 1 and each switching connection point along the loop line or between the switching connection points) fails, the core wire in use of the subscriber in the link fails. At the same time, subscribers on links other than the broken link existing in the loop line including the failed link may also fail. Therefore, first, for the subscribers present in the faulty link, the in-use cord that has failed at the subscriber's connection point is switched to the spare cord. That is, switching at the core level is performed at the subscriber connection point.

And switching at the core level is performed by the subscriber connection point,
That is, since it is performed at the core wire switching point, the number of spare core wires corresponding to the number of failed core wires is guaranteed.

The switching method at the core level will be described with reference to the flowchart of the core level switching algorithm in FIG. In step 101, first remove the faulty part in the cable,
Next, the active cores that do not pass through the failure point are deleted, and a mark ◇ corresponding to the core in use that has failed at the accommodation place of each subscriber on the corresponding link is added. Then, in steps 102 to 104, the subscribers having marks ◇ close to the station are switched in order from the failed cores corresponding to the number of marks ◇ to spare cores connected to the station. If there is no spare core wire connected to the station, it is switched to the spare core wire connected to the switching connection point.

Next, in the step 106, the mark ◇ is deleted from the core wire which has been able to bypass the station by the connection change. Further, when the detour is made to the switching connection point, the mark ◇ is moved to the switching connection point in step 107. Then, in step 108, the spare core wire used for switching is deleted. And mark at step 111 ◇
If there is a subscriber with a mark, the process returns to step 102 and is processed. In this way, the processes of step 102 to step 110 are repeatedly executed until there are no subscribers with the mark.

Next, for subscribers accommodated in links other than the faulty link in the looped line including the faulty link processed based on the flow chart of the core level switching algorithm, the switching connection point is set in units of the above-mentioned core line group. Batch switching is performed by the provided switching connection devices 11 to 14. Since a cable of an adjacent loop line is connected to each switching connection point, the failure is recovered by switching the failed core wire group to the spare core wire group.

That is, the core line group level algorithm is a method of switching the core line group in the switching connection devices 11 to 14 installed at the switching connection point, and this switching method is based on the flow chart of the core line group algorithm of FIG. explain. First, in step 151, the following four processes are performed. That is, in the first process, the broken link is deleted, and in the second process, when the mark ◇ is moved to the switching connection point by the core level algorithm, a new mark ◆ is moved regardless of the number of the moved marks ◇. Attach one. Then, the core wire group that has not failed in the third process is deleted from the network (this causes the network to include the spare core wire groups R1 to R4, the switching connection point and the station 1).
In the fourth processing, a group of cords in use that has failed is marked with the number of failures at the switching connection point farthest from the failure point.

When the four processes are completed in this way, the next step 152
From the switching connection points marked with a, select the switching connection device of the switching connection point that has the fewest number of links connected to the station, and replace the failed core group with the spare core group. Switch to. Then, the processing in steps 153 to 154 is performed. As a result, when the switching connection destination is the station 1, the mark ◆ is deleted in step 155, and when the switching connection destination is another switching connection point, in step 156. Move the mark ◆ to the switching connection point. Subsequently, in step 157, the core wire group used by the detour is deleted, and in step 158, the used core wire that is not used by the bypass is attached. Then, in step 159, if there is a switching connection point with a mark ♦ in the network, the process returns to step 152 again to perform processing. In this way, the processes of steps 152 to 159 are repeatedly executed until there is no switching connection point with the mark ♦.

Using this core group algorithm, it can be seen that the switching method of the switching connection devices 11 to 14 installed at the switching connection point has the following properties. That is, the first property is that all switching at the switching connection point is performed in core line group units, and the second property is the use core line group of the links that are not directly connected to the switching connection point. Is that there is no need for switching connection. As a third property, the spare core wire group may be connected to both the use core wire group and the spare core wire group, and the fourth property is to switch between the use core wire groups. The connection is not made. The switching connection device of the present invention adopts the switching connection function having the above properties, that is, adopts an incomplete wire group configuration (configuration having only a switching function of a specific combination) on a core wire group basis as shown in FIG. By connecting, it is possible to recover the subscriber affected by the failure no matter which link fails.

Next, FIG. 5 (2) shows an example of switching connection of the switching connection device 11 when there is no faulty link. In this figure, since the core group being used is connected to the station along the loop line, the core groups of the same cable are connected at the switching connection point.

Next, FIG. 6 (2) shows an example of switching connection of the switching connection device 11 when the link 21 fails as indicated by a cross mark in FIG. 6 (1). According to this figure, the core wire that cannot be connected to the station due to the failure existing in the failed link 21 is the switching connection device provided at the switching connection point by using the spare core wire group R1 in the link. Detoured until 11. Then, there are the following two types of switching in the switching connection device 11 in this case. That is, the first switching is
Link 31 that has not failed the spare core group R1 of the failed link 21
The second switching is to switch the used core wire group 42 in which the link 22 between the switching connection points existing in the relevant loop line has a failure to the spare core wire group of the link 22.
Switch to R3. The reason for this second switch is
This is because the failure of the link 21 causes a failure of the core wire group 42 of the link 22 between switching connection points existing in the loop line.

Next, an example of the switching connection of the switching connection device when the link 22 between the switching connection points becomes defective as indicated by the cross mark in FIG. 7 (1) (2) of FIG. Shown in the figure. According to this figure, similarly to the switching connection example of FIG. 6, the use core wire of the faulty link is bypassed by using the spare core wire group R3. Therefore, the switching connection point 11 need only have a function of connecting the spare core wire group R3 on the faulty link 22 side to the spare core wire group R1 on the station side link 21 along the loop line. Further, due to the failure of the link 22, the usage core group 41 in the link 21 on the station side also fails, and the failed usage core group 41 is adjacent to the looped line at the switching connection point 11. It is only necessary to have a function of connecting to the spare core wire group R2 of the station side link 31 along the line.

Next, as shown by the cross mark in FIG. 8 (1), the link 23 that is not directly connected to the corresponding switching connection device 11.
An example in the case of failure is shown in FIG. 8 (2). In this example, the connection configuration is similar to that shown in FIG. That is, in the case of the link 22 failure between the switching connection points, the use core wire of the failure link 22 was diverted to the spare core wire group R3, but in the case of FIG. This is the same as the case where the link 22 between the switching connection points eventually fails because it bypasses the use core wire group 41 in which the link 22 between the switching connection points has a failure at the switching connection point 14. .

In the case of the conventional switching connection configuration, the number of switching connections is proportional to N ² as in the equation (1), but in the present embodiment, it is 7
Since the switching connection is performed for each core group by the individual switching contacts C, the number of switching connections can be expressed by the following equation.

Number of switching connections = 7 × Ng (2) Here, Ng is the number of core wires constituting the core wire group, and in the present embodiment, Ng = N / 4 since it is composed of four core wire groups.

Comparing the equations (1) and (2), the number of switching connections increases in proportion to the square of the number of cores in the equation (1) according to the conventional example, whereas the number of switching connections increases according to the present embodiment. In equation (2), the number of switching connections increases in proportion to the number of core wires. That is, if the switching function is configured with a complete line group as in the conventional example, the number of core wires is 2
While the number of switching connections increases in proportion to the power of two, the number of switching connections increases in proportion to the number of core wires when the switching function is configured by the incomplete line group as in the present embodiment. Therefore, in the recovery system of this embodiment, as the number of subscribers increases, recovery work from a failure becomes easier as compared with the conventional switching connection device.

As described above, the failure recovery core wire switching system of the present invention is
In order to simplify the switching connection configuration and switching work in the cable switching device installed at the cable switching connection point, the cable cores are divided into certain bundles, and this bundle is not used as a unit. The core groups are switched and connected by the wire group configuration.

In other words, this system installs a switching connection device that arbitrarily connects the cable core wires between the loop lines in order to improve the core wire use efficiency of the loop cable configuration and shorten the recovery work time when the number of workers is limited. It is a system.

If this fault recovery core wire switching system is used, the spare core wire in the loop line and the spare core wires in other loop lines connected by the switching connection point can be shared, so that the core wire usage efficiency is improved. (By the way, in the case of the network model in Fig. 2, the core usage efficiency is 75%).

As is clear from the above description, the failure recovery core wire switching system of the present invention does not perform core wire switching at the existence points of all subscribers affected by the failure for cable failure recovery, but instead of the switching connection point. It is possible to switch all the core wires at once, and the place where the restoration work is done is limited so that a small number of people can work. That is, all the core wire switching functions in the switching connection device can be configured in units of core wire groups, and the number of switching connections can be realized with a configuration that is extremely small compared to that achieved with the complete wire group configuration. And, the fact that the number of connections is small leads to a reduction in the number of contacts in the device, resulting in a reduction in cost and a simple switching procedure. In addition, the network in which this device is introduced has an advantage that the amount of work related to maintenance and operation can be reduced.

Although the recovery system of this embodiment is applied to the recovery of a cable failure in a communication network, it can also be applied to a failure recovery system for a group of lines arranged in a loop such as an LSI wiring or a power distribution network.

[Effects of the Invention] As described above, according to the fault recovery core wire switching system for a communication network of the present invention, in the event of a cable failure, the subscriber is detoured to the switching connection point in units of one core between the switching connection points sandwiching the failed cable. However, after that, the connection from the switching connection point to the central office was switched and connected in units of core groups, so even if the number of switching connections at the time of restoration increases, the number of switching connections of the switching connection device will be Since the number of switching connection devices is smaller than that of the switching connection device and can be easily configured, there is an effect that the work time at the time of restoration can be shortened.

[Brief description of the drawings]

FIG. 1 is a switching connection configuration diagram showing one embodiment of a communication network fault recovery core wire switching system of the present invention, FIG. 2 is this network model diagram, and FIGS. 3 and 4 are flow charts for explaining this operation. FIGS. 5 to 8 are switching connection configuration diagrams of the core group according to the presence / absence of a broken link, and FIG. 9 is a switching connection configuration diagram to which a conventional restoration system is applied. 1 ... Telephone office, 11-14 ... Switching connection device, 21-23, 31-3
3 ... Link, 41-43, 51-53 ... Core wire group, R1-R4 ...
... Spare core group, C ... Switching contact, J is switching core group.

Claims (1)

(57) [Claims] 1. When a failure occurs in a cable in a subscriber communication network in which a central office is directly connected to a plurality of subscribers by M communication cables each having N cores, a ring is formed. In a restoration system that restores this failure at a switching connection point other than the central office where the laid cable intersects, in the H (1 <H ≦ M) cables connected to the switching connection point, A switching contact, which is provided in the switching connection point and performs connection switching between the H cables in a group of cores with a specific number of cores k (1 <k ≦ N) when an arbitrary cable fails In the case of a cable failure, at the core wire switching point between the switching connection points sandwiching the defective cable, the use core wire in the failure cable is switched to the spare core wire in units of one core and the subscriber is Switch connection After detouring to at least one of the used core wire group and the spare core wire group in the faulty cable from the switching connection point to the telephone station, the switching connection device switches to the spare core wire group in units of the core wire group. A core switching system for communication network failure recovery that connects and recovers subscribers affected by a failure.