JP2000013876A - Optimized allocation method for time slot in t-s-t type switch circuit network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform an efficient optimization processing by successively arranging the line data at and after the sequenced head one in a space area of each of input and output buses with the temporal positions kept between the input and output buses and with those data put close together at the end of each space area. SOLUTION: All lines 1 to 9 in a bus are ordered 1 to N in the descending order of the number of occupied time slots. A variable (n) showing the line order is initialized. Then, an idle area M is retrieved from the head of each of input and output buses of the first line 6 having the largest number of occupied time slots, and a time slot number (m) is decided. Then, it is decided whether the spaces M are secured on both input and output buses, and the time slot number TS of the line 6 is compared with the time slot number M of the space M. If it is decided that the line 6 can be stored, the line 6 is placed in the space M. Then, the variable (n) showing the line sequence is increased by 1, and the processing is returned to the preceding process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TST configured by combining a plurality of time switches and space switches.
More particularly, the present invention relates to a method for optimizing the allocation of time slots in each bus corresponding to a plurality of highways, prior to the exchange of time slots among the plurality of highways by a space switch.

[0002]

2. Description of the Related Art A TST type switch network is widely known as a means for efficiently performing circuit switching between a number of highways. The TST type switch network is a network in which time switches (TSW) are connected by a space switch (SSW). The time switches exchange time slots (TS) at different time positions on the same highway. ,
The space switch exchanges time slots at the same temporal position between different highways. This enables efficient circuit switching between a number of highways.

In such a TST type switch network, in order to accommodate a maximum time slot in a bus provided between a time switch and a space switch,
An optimization process for controlling the time switch on the input side to optimally arrange the lines in the bus is generally performed.

FIG. 3 schematically shows an example of a time slot allocation state in a bus in a case where line switching is performed without performing optimization processing. In this example, the line in the bus B and the space in the corresponding time slot of the bus A are moved by the space switch SSW, and
And an example of outputting to the bus D. Here, the capacity of each bus is 96 time slots.

At this time, if it becomes necessary to set a line between buses A and C that continuously occupies 18 time slots, buses A and C each have a space for 18 time slots. In the time slots corresponding to the buses A and C, an area continuous for 18 time slots cannot be secured. In such a case, it is necessary to perform optimization processing to secure a line capable of accommodating 18 continuous time slots in the bus.

FIG. 4 shows a state after allocation of time slots in a bus optimized using the conventional optimization method. In the figure, an optimization process is performed from the allocation state of FIG.
Is secured. The procedure for obtaining the assignment of FIG. 4 from the assignment of FIG. 3 by the conventional optimization method is as follows. In the conventional processing, the optimization processing is performed mainly on the buses A and C to which a line (18 time slots) is added. The basic algorithm for optimization is to shift the line forward from the beginning and then to the desired space after that.
If (18 time slots in this example) cannot be secured,
The process of moving the left-justified line to the rear free area is repeated. (1) In FIG. 3, since the connection of the line which is the first time slot of the buses A and C is between the buses A and C, the line is moved to an empty area (16 time slots) immediately after the last line. (2) Since the line of the bus C is connected to the bus B, the leading of the buses A and C cannot be performed. Therefore, bus B and bus C
Is moved to an empty area behind the moved line. At this point, at the beginning of buses A and C,
Three time slots are available. (3) Next, pay attention to the lines of the buses A and C, and determine whether or not the lines can be moved to the first time slot. Since the line is a connection between buses A and C, it is moved to the first time slot of each bus. However, 1
Since there is no continuous free space of 8 time slots,
continue processing. (4) Then, the lines of the buses A and C are moved behind the moved lines. (5) Next, the lines of the bus B and the bus C are moved to the first time slot in which both can be moved. However, this movement does not create an empty area of 18 time slots. Therefore, this line should be moved to the empty area in the rear, but since there are no empty 24 time slots in buses B and C, the process proceeds to the next step. (6) The lines of the bus A and the bus C are shifted to the rear of the line. As a result, an empty space for 18 time slots is formed behind the line, and an additional line is set here. In this way, the assignment shown in FIG. 3 is obtained.

[0007]

However, in the above-mentioned conventional optimization method, there is a problem that the management becomes extremely complicated when there are a large number of buses involved in the optimization. That is, in the conventional optimization method, the time slot is operated from the beginning of the bus until a necessary space is formed. However, as the number of operation processes increases, the number of buses to be managed increases, and management becomes complicated. Become. Further, when additional setting of another line is required, the above-described optimization processing needs to be repeated, and there is a problem that the optimization processing must be performed every time a line is added.

It is an object of the present invention to provide a time slot optimizing assignment method that can efficiently perform an optimizing process even when the number of buses involved in the optimization is large. .

Another object of the present invention is to provide a method for optimizing and allocating time slots, which can reduce the number of times of optimization processing each time a line is added by performing efficient optimization.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, prior to the exchange of time slots between a plurality of highways by a space switch, line data occupying one or a plurality of continuous time slots is converted into the space data. In the method for optimizing the allocation of time slots in a TST type switch network, which is switched in each bus corresponding to a plurality of highways arranged on the input / output side of the switch,
(1) a step of ranking all the line data in descending order of the number of occupied time slots; and (2) a vacant area of the input / output bus where the line data is arranged in order from the ranked top line data. And a step of arranging the input and output while keeping the temporal position between the input and output.

In this case, the step (2) comprises: (3) a step of searching for a free area from the head of the input / output bus and obtaining the number of time slots of the searched free area; and (4)
Comparing the number of time slots in the line data with the number of time slots in the free area; and (5) when the number of time slots in the free area is equal to or greater than the number of time slots in the line data as a result of the comparison. Arranging the line data in the vacant area; and (6) if the number of time slots in the vacant area is less than the number of time slots in the line data as a result of the comparison, (3) and a step of repeating (4).

In the present invention, all time slot groups to be switched are subject to optimization from the beginning. Therefore, related buses can be grasped from the beginning, and optimization can be performed efficiently.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on one embodiment shown in the drawings. FIG. 1 is a flowchart embodying the optimization algorithm according to the present invention, and FIG.
5 shows a state after a time slot is allocated in a bus optimized using the method. In the present invention, basically, the following two processes are executed. (1) A step of ranking the time slots in all buses in descending order of the number of occupied time slots. (2) A step of sequentially arranging the time slots between the input and output in the empty area of the input / output bus in which the time slots are arranged, starting from the top ranked time slot.

This will be described below with reference to the flowchart of FIG. 1 and the example of FIG. Here, as in the case of FIG. 4 using the conventional optimization method, it is assumed that a line occupying 18 time slots is additionally set to the time slots set in FIG.

In the first step 101 of FIG. 1, all the lines in the bus are connected in order of decreasing number of occupied time slots.
N (here N = 9). In this example, the lines (TS: 48), (TS: 32), (T
S number: 24), (TS number: 18), (TS number: 3),
(The number of TSs: 2),.
Lines are rearranged. And a variable n indicating the line order
Is initialized (102). In the next step, in the input / output bus of the first line occupying the maximum number of time slots, that is, the bus B and the bus D, the free space M
Is searched, and its size, that is, the number of time slots m
Is obtained (103). Here, the line is the line to be set first, and no lines are set to the buses B and D. Therefore, the number m of the time slots in the free area is both 96 TS.

Next, it is determined whether a vacant area M is secured in both the input / output buses, that is, the bus B and the bus D.
(104). Since the free area M is secured by both buses, the process proceeds to the next processing, and the number of time slots TS
(1) is compared with the number m of time slots in the empty area M
(105). Here, the number m of time slots in the empty area is 9
6 TS, and the number of line time slots TS (1) is 4
Since it is 8, it is determined that the line can be accommodated, and the line is allocated to the empty area M, that is, the head empty area.
(106). Then, the variable n indicating the line order is incremented by one.
(107), the process is returned to step 103 (108).

In step 103, a vacant area M is searched in the input / output buses of the next largest line (the number of TSs: 32), that is, the buses A and C, and the number m of the time slots is obtained. Since the line is the line set first on the buses A and C, it is arranged in the head empty area by the same processing as the line (step 10).
4-108).

Next, with respect to the line to be set, similarly, in step 103, an empty area M is searched for the input / output buses, ie, the buses B and C. Here, since a line has already been set on the bus B and the first 48 time slots are occupied, an empty area M behind it is searched, and its size m (m = 48) is obtained. Similarly,
On the bus C, a time slot at a temporal position corresponding to the empty area M on the bus B is searched, and the empty area size m (m = 64) is obtained. In step 104,
It is confirmed that a free area is secured in both buses, and in step 105, the number of time slots of the line and the number m of time slots of the free area M are compared. Here, the smaller size, that is, m = 48, is adopted as the number of time slots in the free area. Since the number of time slots of the line is 24TS, which is smaller than the size m of the empty area m = 48, the line is set here.

The line to be set next is the added line
(The number of TSs: 18). In step 103, a free area M is searched from the top of the buses A and C for setting the line. Here, on the bus A, the area behind the line becomes an empty area, and its size m = 64 is acquired. An empty area is searched for in the corresponding time slot of the bus C, and its size is obtained. Since a line has already been set behind the corresponding free area of the bus C, the size m of the free area is 16. Since the number of time slots of the line is 18, the processing in step 105
3 and the line is not set for this area.

For the line, step 103 searches for the next free area. The next empty area is a time slot after the line set to the bus C. In this position,
Since sufficient time slot free space can be secured (m
= 24), and a line is set to this position (104 to 106).

The line to be set next is a line (the number of TS:
3), a vacant area is searched on the input / output buses A and C (103). Since there is an empty area with three or more time slots behind the line, the line is set here (104 to 106).

The line to be set next is a line (the number of TS:
2), and an empty area is searched for on the input / output buses B and C (103). Here, on the bus B, there is a sufficient space behind the line, but on the bus C, the corresponding time slot is closed by the line.
Therefore, in step 104, the process returns to step 103, and the next empty area is searched. Then, the line is set behind the line on the bus C. Similarly,
The settings of the remaining lines and are sequentially performed, and the line assignment is completed as shown in FIG.

Here, comparing the line set by the above-described optimization method of the present invention (FIG. 2) with the line set by the conventional method (FIG. 4), It can be seen that the number of time slots corresponding to the empty areas is larger than that of the conventional method. Therefore, when assigning a new line,
In the case of the present invention, without rearranging the line again,
It can be said that the possibility of being assigned a time slot is higher than in the case of the conventional method. For example, in the case of FIG. 4, when a new line occupying 11 time slots is added, in the case of FIG. 4, the line exchange from the bus A to the bus C and from the bus B to the bus C becomes short of free space. Need to be optimized again. In contrast, in the case of FIG.
Only the circuit switching from the bus B to the bus C runs out of free space, and other circuit switching, that is, the bus A to the bus B, the bus A
To bus C and bus B to bus D for 11 time slot lines.

The embodiment of the present invention has been described with reference to the drawings. However, it is apparent that the present invention is not limited to the matters described in the above embodiments, and that changes, improvements, and the like can be made based on the description in the claims. In the embodiment, for convenience of description, the process of optimizing the time slot in each of the two buses on the input and output sides has been described.
Obviously, the present invention can be applied to a TST switch having a larger number of buses.

[0025]

As described above, according to the present invention, even when the number of buses involved in the optimization is large, the optimization processing can be efficiently performed. Optimization processing can be reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart embodying an optimization algorithm according to the present invention.

FIG. 2 is a diagram showing a state after allocation of a time slot in a bus optimized according to the present invention;

FIG. 3 is a diagram illustrating an example of a time slot allocation state in a bus when circuit switching is performed without performing an optimization process.

FIG. 4 is a diagram showing a state after a time slot is allocated in a bus optimized using a conventional optimization method.

[Explanation of symbols]

 SSW space switch TSW time switch ~ setting line

Claims (2)

[Claims] 1. Prior to time slot exchange between a plurality of highways by a space switch, line data occupying one or a plurality of continuous time slots is made compatible with a plurality of highways arranged on the input / output side of the space switch. In the method for optimizing the allocation of time slots in a TST type switch network to be exchanged in each bus, (1) a step of ranking all the line data in the descending order of the number of occupied time slots; and (2) Sequentially arranging the line data in the empty area of the input / output bus in which the data is arranged, starting from the top-ranked line data, while maintaining the temporal position between the input and output. Optimizing time slot allocation method in a TST type switch network. 2. The step (2) includes: (3) searching for a free area from the head of the input / output bus, and acquiring the number of time slots of the searched free area; (5) comparing the number of time slots with the number of time slots in the free area; and (5) if the result of the comparison indicates that the number of time slots in the free area is equal to or greater than the number of time slots in the line data, Arranging the line data in the empty area; and (6) as a result of the comparison,
If the number of time slots in the empty area is less than the number of time slots in the line data, the step (3)
And (4). A method for optimizing the assignment of time slots in a TST type switch network, comprising the steps of: