JPH07226767A - Digital exchange - Google Patents

Abstract

(57) [Abstract] [Purpose] Efficiently secure a data transmission path by managing free channels and free capacity of sub-rate communication controllable communication channels between multiple communication terminals connected to a digital exchange. . [Structure] The digital exchange 2 has a plurality of compression encoding /
It has a sub-rate communication control section 5 having a decoding means, and a capacity management means 4 for managing a vacant channel and a vacant capacity of the communication channels controlled by the sub-rate communication. As described above, by providing the capacity management means 4, it becomes possible to efficiently secure the data transmission path while managing the free channel and the free capacity of the communication channels under the sub-rate communication control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital exchange, and more particularly to a digital exchange capable of sub-rate communication control by having a plurality of compression encoding / decoding means. The present invention relates to a digital exchange that efficiently secures a data transmission path by providing a capacity management means for managing the free capacity of the.

[0002]

2. Description of the Related Art In a conventional digital exchange capable of controlling sub-rate communication by using compression encoding / decoding technology, when communication with a game is started using a trunk for sub-rate exchange, it depends on the amount of communication traffic. The sub-rate communication control is performed while the compression rate remains fixed until the end of the communication without dynamically changing the compression encoding method during the communication.

A known document describing a conventional digital exchange is, for example, Japanese Patent Laid-Open No. 4-79444. This publication discloses that in a time division digital exchange of a system in which data from a plurality of low-speed data terminals are inserted into a time slot consisting of a predetermined number of bits in a high-speed format and transmitted, a plurality of low-speed data converted into an ultra-high-speed format. A sub-rate exchange trunk for extracting effective bits only from the time-multiplexed time-multiplexed channel time slot having the predetermined number of bits, and performing reverse processing to separate the time-division digital exchanges is provided. The time slot is transmitted to the game station, and the multiplexed time slot from the game station is separated and transferred to a plurality of low-speed data terminals.

[0004]

In such a digital exchange, it is possible to perform sub-rate communication with the opposite station, but the data compression rate in sub-rate communication is fixed from the start to the end of communication, and the communication quality is high. It has been impossible to effectively utilize the communication line by giving priority to the communication line or dynamically changing the data compression rate as the communication traffic increases.

The present invention has been made in view of the above circumstances, and in a digital exchange, communication control means for performing sub-rate communication control of a communication channel between communication terminals connected to the digital exchange, and communication. It is an object of the present invention to provide a digital exchange in which a data transmission path is efficiently secured by providing an empty channel and a capacity management means for managing the free capacity.

[0006]

In order to solve the above-mentioned problems, the present invention provides (1) a plurality of compression encoding / decoding means, thereby providing a plurality of digital exchanges capable of sub-rate communication control. A sub-rate communication control means for dividing and controlling a communication channel between communication terminals into low-speed capacity calls by a plurality of data compression encoding / decoding methods, and a free capacity in a communication channel divided into a communication channel and a plurality of low-speed capacity calls And (2) the sub-rate communication control means has a plurality of compression encoding / decoding means, or (3) predetermined data from a connected communication terminal. A digital exchange that inserts into a time slot consisting of bits and transmits, and compresses data from a plurality of communication terminals connected to the digital exchange. The data is converted into low-speed data by encoding, is multiplexed into a time slot of one channel having the above-mentioned predetermined number of bits, and the low-speed data is separated from the multiplexed time slot transmitted from the game, and is compression-encoded low-speed data. In a digital exchange capable of sub-rate communication control that performs decoding of the sub-rate, when a call generated due to a data transmission request is connected, the presence or absence of the communication channel to which the sub-rate communication control is applied is confirmed, and the sub-rate communication is performed. If the communication channel to which the control is applied already exists, check the free capacity of the communication channel. If the communication channel does not exist, check the free capacity of any free communication channel. And then subdivide the capacity until it becomes physically impossible, so that new calls are slower than free capacity. The capacity management means for managing the capacity that allocates provided, in which was characterized by efficiently performing the secure data transmission channel.

[0007]

According to the present invention, a digital exchange accommodates a plurality of communication terminals, and a sub-rate for dividing and controlling a communication channel between the communication terminals into low-speed capacity calls by a plurality of data compression encoding and decoding systems. Since the communication control unit and the capacity management means for managing the free capacity in the communication channel and the communication channel divided into a plurality of low-speed capacity calls are provided, the communication terminals of the digital exchanges (via the central line) It is possible to effectively use the data transmission capacity (including the communication terminal connected).

[0008]

Embodiments will be described below with reference to the drawings. FIG. 1 is a block diagram for explaining an embodiment of a digital exchange and a communication terminal connected to the digital exchange according to the present invention, in which 1a to 1c are communication terminals and 2
Is a digital exchange, 3 is a line I / F (interface), 4 is capacity management means, 5 is a sub-rate communication control unit,
Reference numeral 6 is a communication path, 7 is a line I / F (interface), and 8 is a network.

The digital exchange according to the present invention divides a communication channel that physically connects the accommodated communication terminals or the communication terminals connected via a central line into a plurality of low-speed capacity calls. And a sub-rate communication control section 5 having compression encoding / decoding means by a plurality of compression encoding / decoding methods, and a capacity management means 4 for managing an empty communication channel and an empty capacity in the communication channel. ing. In the capacity management means 4, the number of free channels and the free capacity of the communication channels between the communication terminals are managed, and the communication channels are subdivided until the sub-rate communication control unit 5 cannot physically divide the communication channels. It is possible to efficiently secure the data transmission path.

2 to 4 are flowcharts showing an efficient capacity management procedure. Hereinafter, each step (S) will be described in order. In the figure, N is the number of free communication channels, m is the data transmission rate of the communication channels, x is the free capacity value, m / (2 to the nth power) is the lowest speed capacity call price, and y is the corresponding data in the subrate communication control unit. The transmission rate, ymax, is the maximum data transmission rate of the compression encoding / decoding means remaining in the sub-rate communication control unit, and z is the data transmission rate of the call for which the disconnection request has occurred.

Here, for simplicity of explanation, it is assumed that the sub-rate communication control is applied to only one arbitrary communication channel. Furthermore, the sub-rate communication control unit 5 uses m (kb /
s) data, m (kb / s) 1 / (2 to the nth power)
A plurality of compression encoding / decoding for performing compression encoding and decoding on data having a data transmission rate (where n is a natural number)
It has a decryption means.

First, when a call connection request or call disconnection request is generated in the request waiting state (S1) (S2), it is judged which request is the request (S3). In S3, when the generated request is a connection request, the capacity managing means first confirms the presence or absence of an empty communication channel (S4). In S4, when there is no free communication channel, that is, when the number N of free communication channels is 0, the capacity management means determines that the channel that is performing the sub-rate communication control is the communication channel that is already connected. Whether it exists or not is confirmed (S5). S5
If there is no communication channel performing sub-rate communication control, the call cannot be connected. Therefore, the disconnection procedure is started (S6). After the disconnection procedure is completed, the procedure returns to S1.

Further, in S5, when there is a communication channel for which the sub-rate communication control is performed, the capacity management means sets the free capacity value x (kb / kb) of the communication channel.
The existence of s) is confirmed (S7). In S7, when the free space value x (kb / s) is not 0, that is, when there is free space, it is judged from the free space value,
It is determined whether or not it is possible to perform communication by dividing the capacity into half the free capacity value (S8). That is, x / 2 (k
b / s) and m / (n to the power of 2) (kb / s) are compared in magnitude.

Here, x / 2 (kb / s) is equal to m / (2 to the nth power) (kb / s), or m (kb / s)
If it is larger than s), it is determined that it is possible to divide the free capacity by sub-rate communication control into half capacity. In the opposite case, it is determined that it is impossible to divide the free space any more.
However, in the determination here, it is determined whether the division is possible / impossible based only on the free capacity value, so it is necessary to provide a determination from the physical condition in the next step.

In S8, when it is determined that the communication can be performed by dividing the capacity into half the free capacity, that is, x / 2 (kb / s) ≧ m (2 to the nth power) (kb /
In the case of s), the possibility of call connection is obtained by searching for a compression encoding / decoding means that is currently unused among the plurality of compression encoding / decoding means included in the sub-rate communication control unit 5. Is determined (S9).

In S9, y (kb / s) = x / 2 at the data transmission rate y (kb / s) which can be supported by the unused compression encoding / decoding means in the sub-rate communication control section.
When there is a compression encoding / decoding means that satisfies the condition of (kb / s), the data transmission rate x / 2
The sub-rate communication control of (kb / s) is determined, the negotiation regarding the sub-rate communication control is performed between the communication terminals that have generated the connection request, and the data transmission rate x / 2 (kb / s)
The low-speed capacity call of s) is connected (S10).

Further, x (kb / s) of the free capacity value is x
It is updated to / 2 (kb / s) (S11), and the process proceeds to S1. In S9, the sub-rate communication control unit 5 displays y (kb
/ S) = x / 2 (kb / s), if there is no compression encoding / decoding means satisfying the condition of y, then y
The presence / absence of compression encoding / decoding means that satisfies the condition of (kb / s) <x / 2 (kb / s) is confirmed (S12).

In step S12, when the sub-rate communication control unit has the compression encoding / decoding means that satisfies the above condition, the maximum data transmission rate ymax of the compression encoding / decoding means that satisfies the condition is present. The sub-rate communication control by the compression encoding / decoding means corresponding to (kb / s) is determined, the sub-rate communication control is negotiated between the communication terminals having the call connection request, and the data transmission rate ymax (kb / s). ) The low speed capacity call is connected (S13). Further, the free capacity value x (kb / s) is updated to (x-ymax) (kb / s) (S14), and the process proceeds to S1.

In S12, the sub-rate communication control unit 5
If there is no compression encoding / decoding means satisfying the condition of y (kb / s) <x / 2 (kb / s), then y
The presence / absence of compression encoding / decoding means satisfying the condition of (kb / s) = x (kb / s) is confirmed (S15). In S15, if the sub-rate communication control unit 5 has a compression encoding / decoding means that satisfies the above conditions, the compression encoding / decoding means corresponding to the data transmission rate x (kb / s) is used. Sub-rate communication control is determined, and the sub-rate communication control is negotiated between the communication terminals that have made a call connection request, and the data transmission rate x (kb / kb /
The low-speed capacity call of s) is connected (S16). Further, the free capacity value x (kb / s) is updated to 0 (S17), and the process proceeds to S1. In this case, since the data transmission capacity of all the communication channels is used by connecting the call for which the connection request is generated, it is impossible to secure another data transmission path.

If there is no compression encoding / decoding means that satisfies the condition of y (kb / s) = x (kb / s) in the sub-rate communication control unit 5 in S15, the call Since the connection is impossible, a call disconnection procedure for the connection request is entered (S6), and after the disconnection procedure is completed, the procedure returns to S1. When it is determined in S8 that it is impossible to communicate by dividing the free space into half, that is, x
In the case of / 2 (kb / s) <m / (2 to the nth power) (kb / s), the condition of x = m / (2 to the nth power) is satisfied at the same time, and the process proceeds to S15. The processing from S15 onward is performed.

In S7, when the free capacity value x (kb / s) of the communication channel which is performing the sub-rate communication control is 0, there is no free data transmission path, so the call is disconnected in response to the connection request. After entering the procedure (S6) and completing the cutting procedure, the procedure returns to S1. Further, in S5, when there is no communication channel for which the sub-rate communication control is performed, the call disconnection procedure for the connection request is entered (S6), and after the disconnection procedure is completed, the process returns to S1.

In S4, when it is confirmed that there is a free channel in the communication channels, that is, when the free communication channel number N is not 0, the free communication channel number N
It is determined whether or not is 1 (S18). If N = 1 is determined in S18, it is confirmed whether or not there is a channel for which sub-rate communication control is being performed among the communication channels that are already connected (S19). S
If there is a communication channel for which the sub-rate communication control is performed in 19, the idle communication channel confirmed in S4 is connected (S20). further,
The number N of free communication channels is updated to a value obtained by subtracting 1 from the current value of N (S21), and the process returns to S1.

In S19, if the existence of the communication channel for which the sub-rate communication control is being performed is not confirmed, it is determined that the sub-rate communication control is to be performed on the only free communication channel, and the free capacity value of the free communication channel is determined. x
The default value m (kb / s), that is, the capacity value of the communication channel is set to (kb / s) (S22), and the process proceeds to S8. If N ≠ 1 is determined in S18, that is, if there are a plurality of free communication channels, the process proceeds to S20, and one of the free communication channels among the free communication channels confirmed in S4 is connected. (S20), and the process proceeds to S21 and subsequent steps.

When it is judged in S3 that the generated request is a disconnection request, the data transmission rate z (kb / s) of the call in which the disconnection request is generated is z (kb / s) = m (kb /
It is determined whether or not the condition (s) is satisfied (S23).
In S23, if the above conditions are satisfied, that is, if the call for which the disconnection request has been issued is a call for which sub-rate communication control has not been performed, the number of idle communication channels N is incremented by 1 from the current value of N. Update to the value you have done (S2
4) The call disconnection procedure is started (S6).

In S23, z (kb / s) ≠ m (k
b / s), that is, if the call for which the disconnection request has occurred is a call by subrate communication control, the free capacity value x (kb / s) is updated to (x + z) (kb / s) Yes (S25). In addition, the updated free space value x
(Kb / s) and the capacity value m (kb / s) of the communication channel
Is compared with (S26).

In S26, x (kb / s) ≠ m (k
b / s), that is, even if the low-speed capacity call for which the disconnection request has occurred is disconnected, there are other low-speed capacity calls in communication in the communication channel including the low-speed capacity call. If so, the call disconnection procedure is started as it is (S
6). Further, in S26, x (kb / s) = m (k
b / s), that is, when the communication channel including the low-speed capacity call becomes a free channel by disconnecting the low-speed capacity call for which the disconnection request has occurred, the free capacity value x ( kb / s) is updated to 0 (S2
7) Further, the number N of available communication channels is updated to a value obtained by adding 1 to the current value of N (S24), and the call disconnection procedure is started (S6).

As described above, the digital exchange according to the present invention has a sub-rate communication control section having a plurality of compression encoding / decoding means, and a capacity for managing an empty channel and an empty capacity of the communication channels subjected to the sub-rate communication control. Since the management means is provided, the data transmission path can be secured while efficiently managing the capacity.

[0028]

As is apparent from the above description, the present invention, in the digital exchange according to the present invention, performs compression encoding / decoding corresponding to a plurality of systems for performing compression encoding and decoding of data. Since it has a sub-rate communication control means having a means and a capacity management means for managing the free capacity so that a low speed capacity equal to or less than the free capacity is allocated to a new call as long as the sub-rate communication control is physically possible, In a digital exchange, the data transmission rate between communication terminals is not set as a default value from the beginning, and the data transmission rate is dynamically set based on the free channel and free space of the communication channel. Quality can be guaranteed as much as possible.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of a digital exchange and a communication terminal connected thereto according to the present invention.

FIG. 2 is a flowchart (part 1) for explaining an efficient capacity management procedure of the digital exchange according to the present invention.
Is.

FIG. 3 is a flowchart (part 2) for explaining an efficient management procedure of the capacity of the digital exchange according to the present invention.
Is.

FIG. 4 is a flowchart (part 3) for explaining an efficient capacity management procedure of the digital exchange according to the present invention.
Is.

[Explanation of symbols]

1a to 1c ... communication terminal, 2 ... digital exchange, 3 ... line I / F (interface), 4 ... capacity management means, 5 ...
Sub-rate communication control unit, 6 ... communication path, 7 ... line I / F
(Interface), 8 ... network.

Claims (3)

[Claims] 1. In a digital exchange capable of sub-rate communication control by having a plurality of compression encoding / decoding means, a communication channel between a plurality of communication terminals is operated at a low speed by a plurality of data compression encoding / decoding methods. A digital exchange comprising: a sub-rate communication control means for controlling division into capacity calls; and a capacity managing means for managing free capacity in a communication channel and a communication channel divided into a plurality of low-speed capacity calls. 2. The digital exchange according to claim 1, wherein said sub-rate communication control means has a plurality of compression encoding / decoding means. 3. A digital exchange that inserts data from a connected communication terminal into a time slot having a predetermined number of bits and transmits the compressed data, and compresses data from a plurality of communication terminals connected to the digital exchange. Conversion to low-speed data, multiplexing into a time slot of one channel consisting of the predetermined number of bits, separating the low-speed data from the multiplexed time slot transmitted from the game, and compressing the low-speed data. In a digital exchange that enables sub-rate communication control for decoding,
When connecting a call generated by a data transmission request, check whether there is a communication channel to which subrate communication control is applied, and if a communication channel to which subrate communication control is applied already exists. Checks the free capacity of the communication channel, and if there is no communication channel, checks the free capacity of any free communication channel and subdivides the capacity until it becomes physically impossible. As a result, a digital exchange characterized by providing a capacity management means for managing a capacity for allocating a lower speed capacity than a free capacity to a new call, and efficiently securing a data transmission path.