JPH1065729A - Overflow call alternate system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently control the connection/disconnection of an ISDN line when the overflow call of an HD(high-speed digital) line is bypassed to the ISDN line. SOLUTION: When a present band usage rate is (A), a threshold Sc=Wo-Wc where the speed of a stand-by channel is decided by the total sum band width Wc(in proportion to speed) of the two high-order channels(1 and 3) and allotment possible band width Wo is defined. When the first channel within the stand-by channels is connected (B), the speed of the stand-by channel becomes the total sum band width of the two high-order channels(3 and 4) in new Wc and becomes smaller so as to change Sc. But the band usage rate exceeds Sc so that the ISDN line is connected as shown in a figure (C) so as to enlarge an allotable transmission path band width.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overflow call rerouting system, and more particularly to an overflow call rejection system for high-speed digital circuits.
The present invention relates to an overflow call diversion system in which diversion control is performed using N lines.

[0002]

2. Description of the Related Art As a technique relating to this kind of overflow call rerouting system, for example, there is a technique disclosed in Japanese Patent Application Laid-Open No. Hei 6-132969. In this overflow call rerouting method using an ISDN line, when an ISDN line for accommodating an overflowed path is connected, the total usage rate of the HD (high-speed digital) line and the connected ISDN line is fixed. The threshold (threshold) is exceeded.

In this method, depending on the connection state of the path, the subsequent path connection is made within the HD line and the connected IS
In some cases, it is only necessary to be in the DN line,
Although the DN line is connected for overflow call diversion,
No path is assigned to the DN line. In this case, useless connection of the ISDN line is performed.

[0004] Conversely, when the threshold is raised,
In an overflow call rerouting of a path with a high speed (that is, a large transmission bandwidth), there are cases where an ISDN line cannot be pre-connected.

[0005]

SUMMARY OF THE INVENTION Overflow call bypass ISD
The trigger for connecting the N lines was that the usage rate of the transmission line exceeded a certain threshold. in this case,
When the threshold is set low, the pre-connection for bypassing the overflow is more reliable as the threshold is lower, but the time when the ISDN line is connected but the path is not actually allocated increases. Conversely, if the threshold is set high, the pre-connection for overflow call redirection becomes more uncertain as the threshold is higher.

In other words, if an attempt is made to perform the pre-connection more reliably, the useless connection time of the ISDN line as described above becomes longer. However, it is a problem to minimize this useless connection.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an overflow call for controlling connection / disconnection of an overflow call bypass ISDN line more efficiently. It is to provide a detour system.

[0008]

According to the present invention, an overflow call for a high-speed digital line is provided.
An overflow call diversion system configured to bypass to the N line, wherein the overflow call diversion ISDN line is set in accordance with a use state of the high-speed digital line and a transmission bandwidth of a standby channel which is not connected and is waiting. Threshold value control means for setting and controlling a connection / disconnection threshold of a line usage rate that triggers connection / disconnection; and a connection of the overflow call bypass ISDN line when it is determined that the line usage rate exceeds the connection threshold value. Connection / disconnection control means for disconnecting the overflow call bypass ISDN line when it is determined that the line usage rate is smaller than the disconnection threshold value. Can be

[0009] The connection / disconnection control means starts the connection only when the line usage rate exceeds the connection threshold for a certain period of time. The disconnection is started only after the state where the line usage rate becomes smaller than the disconnection threshold continues for a certain period of time.

[0010] Further, the threshold value control means sets a bandwidth required for transmission of a predetermined number of higher-order channels extracted in descending order of transmission bandwidth among the standby channels as Wc, and an allocatable transmission path bandwidth as Wo. The connection threshold Sc
Is set by Sc = Wo−Wc, and the threshold control unit sets a bandwidth required for transmission of a predetermined number of upper-order channels of the standby channels extracted in descending order of transmission bandwidth to Wd, When the allocatable transmission path bandwidth is Wo, the connection threshold value Sd is set by Sd = Wo-Wd.

The connection / disconnection control of the overflow call bypass ISDN line is performed in accordance with the use state (line utilization rate) in the transmission line, and the overflow call bypass ISDN line is controlled by the transmission bandwidth of the demand waiting (standby state) channel. By changing the threshold value of the line usage rate that triggers connection / disconnection, more appropriate connection / disconnection control of the overflow call bypass ISDN line can be performed.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram showing the principle of an embodiment of the present invention. Referring to FIG. 1, a multiplexing system accommodating information of general data terminals, voice terminals, and frame relay terminals is shown. The terminal connection unit 11 terminates input / output information of these terminals (not shown).

As the line connection unit, an HD line connection unit 16 for terminating HD line input / output information and an ISDN line connection unit 17 for terminating ISDN line input / output information are provided. The disconnection / connection processing is performed by the ISDN line connection / disconnection control unit 14.

The TSW 15 switches input / output information between the terminal connection unit 11 and the line connection units 16 and 17 in response to the transmission line allocation information and the band switching timing information from the band allocation control unit 13. .

The demand detecting unit 12 receives connection requests and disconnection requests from the data terminal and the voice system terminal, and transmits the request to the terminal connecting unit 11.
, And notifies the band allocation control unit 13 of the demand. This bandwidth allocation control unit 13 is a demand detection unit 1
2 is the demand of each terminal, determines the bandwidth allocation on the transmission line, controls the setting of the TSW 15,
It instructs the DN line connection / disconnection control unit 14 to connect / disconnect the ISDN line.

FIG. 2 is a block diagram of the embodiment of the present invention, and the same functional parts as those in FIG. 1 are denoted by the same reference numerals. Referring to FIG. 2, in the present embodiment, the terminal interface unit 3
02, a demand detecting unit 12 for detecting a demand connection / disconnection request from the demand terminal interface unit 302
And a demand control unit 305 for notifying the demand terminal 302 of permission for demand connection / disconnection, a frame relay terminal interface 301, and a demand terminal interface 3
02, a multiplex processing unit 308 for switching data from the fixed allocation terminal interface 303 and data from the transmission line, a LIF (line interface) connection unit 16 for terminating data of a dedicated line which is an HD line, a demand request A control unit 1 that collects information, changes a transmission line band, communicates control information from the opposite station, and sets transmission line band allocation.
3 and an ISDN line connection / disconnection processing unit 14 for connecting / disconnecting the ISDN line in accordance with an instruction from the control unit 13
And an ISDN line connection unit 17 for terminating the data of the ISDN line.

FIG. 3 is a flowchart showing the operation of the embodiment of the present invention. An embodiment of the present invention will be described below with reference to the flowchart of FIG.

First, individual channels (demand terminals 302) are classified and registered in advance as any of "pre-connection channels", "post-connection channels", and "connection prohibition channels". The “pre-connection channel” and the “post-connection channel” are paths that perform overflow call detour, and the “connection prohibited channel” is a path that does not perform overflow call detour.

More specifically, the "pre-connection channel"
This channel is a target of the present invention, and is currently in a standby state. However, if it is expected that the channel will not be allocated to the HD line when a connection request is made in the future,
A determination is made as to whether a predetermined number (Nc) of channels, which are to be connected to the SDN line and are extracted in order of transmission (transmission path bandwidth), can be allocated to the HD line. A certain time (connection protection time) Tc
This channel is a determination target channel for connecting an ISDN line when it is continued.

The “post-connection channel” is not a pre-connection channel and is not a pre-connection channel.
This channel is to be assigned to the ISDN line if it cannot be assigned to the HD line.

The "connection prohibited channel" is a channel whose importance is lower than that of the above two channels and which does not need to be connected to the ISDN line when it cannot be allocated to the HD line.

For the pre-connected channel, it is determined whether or not the upper Nc channels extracted in order of speed from the pre-connected channel that is unconnected and waiting for a demand (standby state) can be allocated to the HD line, and cannot be allocated. When the connection state continues for the connection protection time Tc, the ISDN line is connected.

That is, each time the line use condition changes, the line use ratio is calculated. When the line use ratio exceeds the threshold value Sc calculated under this condition and the state continues for the connection protection time Tc or more, the ISDN line Will be connected. Also, when calls are concentrated and overflow, the connection is made immediately.

If it is impossible to assign the post-connection channel to the HD line and the connected ISDN line at the time of the demand request, a new ISDN line is immediately connected and allocated.
The post-connection channel is not subject to the pre-connection determination.

Circuit disconnection means that the upper Nd channels extracted in the order of speed from the unconnected pre-connected channels have no paths in a certain ISDN line,
If the state of being able to be allocated to the DN line continues for the disconnection protection time Td, the ISDN line is disconnected.

The operation for changes in the demand channel use state and the transmission path use state will be described below.

[0028] The demand detecting unit 12 is connected to the demand terminal 302.
Connection request, for example, ER (Dat
a Terminal Ready or RS (Re
quest to Send), SS for voice terminals
(Status signal of connection / disconnection of voice channel from PBX)
Is detected as a trigger (step 40)
1), the control unit 13 requests the demand terminal, the type,
The transmission path band allocation is calculated based on the communication speed and the like (steps 402 and 403). HD line or connected ISD
If not assigned to N lines, a new ISDN
A line is connected, and a path is set to the multiplex processing unit 15 based on the calculated assignment (step 404).

The controller 13 calculates a threshold value for the overflow call alternate line connection in the state of the transmission line band allocation at that time (step 405). First, let Wc be the bandwidth required for transmission of the upper Nc channels extracted in order of speed from the pre-connected channels that are not connected and are waiting for demand (standby state).

Further, Sc = (allocatable transmission path bandwidth) -Wc is the connection threshold value.

The transmission line band utilization is calculated by the new transmission line band allocation, and if Sc ≧ band utilization ratio, the connection of the new bypass ISDN line is not performed. If the state of Sc <bandwidth utilization continues for the connection protection time Tc, a new detour I
An SDN line is connected (steps 406 to 408).

T while the band usage rate exceeds Sc.
If c or more has elapsed, the control unit 13 requests the ISDN line connection / disconnection processing unit 14 to overflow the call bypass ISDN line connection. The ISDN line connection / disconnection processing unit 14 performs a calling process to a target destination, connects the ISDN line, and secures a band. The newly secured band is also an allocatable transmission line band.

The operation when the ISDN line is disconnected will be described below. The demand detector 12 is a demand terminal 30
2, the control unit 13 deletes the path of the demand terminal that has requested the disconnection, for example, if a change in ER or RS for a data terminal or a change in SS for a voice terminal is detected as a trigger (step 401). The setting is performed for the multiplex processing unit 15.

The control unit 13 calculates a threshold value for the overflow call alternate line connection in the state of the transmission line band allocation at that time (step 405). First, let Wd be the bandwidth required for transmission of the upper Nd channels extracted in order of speed from the pre-connected channels that are not connected and are waiting for demand (standby state).

Further, Sd = (allocatable transmission path bandwidth) -Wd is a threshold value.

The transmission line bandwidth utilization rate is calculated by the new transmission path bandwidth allocation, and there is an SDN ≧ bandwidth utilization rate, and there is an overflowable call bypass ISDN line to which no path is allocated and which can be disconnected.
If continued, disconnect (steps 409, 410, 41)
1).

If Sd <bandwidth utilization, the overflow call bypass ISDN line is not disconnected.

When Td or more elapses while the band usage rate is Sd or less, if there is an ISDN line to which no path is assigned, the control unit 306 sends the ISDN line connection / disconnection processing unit 14 to the line. Request a disconnect. IS
The DN line connection / disconnection processing unit 14 disconnects the ISDN line by performing a line disconnection process for a target destination.

FIGS. 4A and 4B show examples of transmission line band control. FIGS. 4A and 4B show the state before and after the threshold value changes when Nc = 2. In this example,
When the second channel among the pre-connected channels is a connected channel, the other channels are in a standby state (A), and when the first channel is changed from non-connected to connected, the band usage rate (indicated by hatching) becomes a threshold Sc. , But does not exceed the new threshold Sc ′ (B).
This indicates that N-line connection is not performed.

That is, as shown in FIG. 4A, even if the transmission line usage rate exceeds the previous threshold Sc, the preconnected channels in the standby state are extracted in order of increasing speed (in order of increasing bandwidth). Since the speeds (corresponding to Wc) of the two highest-ordered channels (Nc = 2) have changed and have decreased from Wc of (A) to Wc of (B), the new threshold Sc ′ has become higher than Sc. Also changes to a larger one, and as a result, the upper two channels can be assigned. Therefore, connection of the ISDN line is not performed.

FIG. 5 shows a case where Nc = 2 as in FIG. 4, in which the second of the pre-connected channels is already connected,
Others are in the standby state (A), and when the first channel is changed from non-connection to connection, the bandwidth usage exceeds the new threshold Sc '(B), so that the ISDN line connection is performed (C). .

After connection of the ISDN line (C), the allocatable transmission line bandwidth increases accordingly, so that the new threshold changes to Sc ″ shown in (C).

FIG. 6 shows an example of a temporal change of the transmission line band allocation according to the embodiment of the present invention.

As described above, when the connection of the overflow call bypassing ISDN line is disconnected depending on the use state in the transmission path, the overflowing call bypassing ISDN is determined depending on which channel is waiting for demand at that time. Line connection /
By changing the threshold value of the transmission path utilization rate that triggers disconnection, the overflow call bypass IS
Connection and disconnection of the DN line can be performed.

[0045]

According to the present invention, an ISD for overflow call redirection is provided.
The use of N lines is more efficient. The reason is that by changing the threshold used as the reference for the connection trigger depending on the state of the channel in the standby state, it is possible to shorten the useless connection while pre-connecting the ISDN line.

[Brief description of the drawings]

FIG. 1 is a schematic system block diagram illustrating the principle of the present invention.

FIG. 2 is a block diagram of an embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the embodiment of the present invention.

FIG. 4 is a diagram illustrating an example of a change in a threshold value that triggers connection of an ISDN line.

FIG. 5 is a diagram illustrating another example of a change in a threshold that triggers connection of an ISDN line.

FIG. 6 is a diagram showing an example of a temporal change in transmission line band allocation according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 11 terminal connection unit 12 demand detection unit 13 bandwidth allocation control unit 14 ISDN line connection / disconnection control unit 15 TSW 16 HD line connection unit 17 ISDN line connection unit 301 frame relay terminal interface unit 302 demand terminal interface unit 303 fixed allocation terminal interface unit 305 Demand control unit

Claims (5)

[Claims] 1. An overflow call diversion system wherein an overflow call for a high-speed digital line is diverted to an overflow call bypass ISDN line, wherein the use state of the high-speed digital line and a standby channel which is not connected and is waiting. Threshold control means for setting and controlling a connection / disconnection threshold value of a line usage rate that triggers connection / disconnection of the overflow call bypass ISDN line in accordance with the transmission bandwidth of the call, and wherein the line usage rate exceeds the connection threshold value Connection / disconnection for connecting the overflow call bypassing ISDN line when it is determined that the overflowing call bypassing ISDN line is smaller than the disconnection threshold value. An overflow call diversion system, comprising: a control unit. 2. The overflow according to claim 1, wherein the connection / disconnection control means starts the connection only after a state where the line usage rate exceeds the connection threshold continues for a certain period of time. Call routing system. 3. The connection / disconnection control unit is configured to start disconnection only when a state in which the line usage rate becomes smaller than the disconnection threshold continues for a certain period of time. Or the overflow call diversion system according to 2. 4. The threshold control means, wherein the bandwidth required for transmission of a predetermined number of higher-order channels extracted from the standby channels in descending order of transmission bandwidth is Wc, and the allocatable transmission path bandwidth is Wo. Wherein the connection threshold value Sc is set by the following formula: Sc = Wo-Wc.
3. The overflow call diversion system according to any one of 3. 5. The threshold control means, wherein the bandwidth required for transmission of a predetermined number of higher-order channels extracted from the standby channels in descending order of transmission bandwidth is Wd, and the allocatable transmission path bandwidth is Wo. Wherein the connection threshold value Sd is set by the following formula: Sd = Wo-Wd.
4. The overflow call diversion system according to any one of 4.