JPH04345241A - Input traffic control method - Google Patents

Abstract

PURPOSE:To prevent a call processing processor from being congested even at a concentrated traffic by allowing a signal processing section to monitor the arrival density of a call connection request frame and not giving the call connection request frame to the call processing processor but giving an interrupt command or the like thereto when the density exceeds a specified value. CONSTITUTION:A counter 206 or the like of a congestion control section 214 of a signal processing section 218 always monitors the arrival density of a call connection request frame. Then a call interrupt command is outputted from a call reception reject/interrupt frame generating section 209 when the arrival density from a congestion detection section 208 is a specified value or over based on the specified value stored in a register 207 and the call connection request frame is not given to a call processing processor 212 of a call control section 219. Thus, even when traffics are concentrated tentatively due to simultaneous calling or simultaneous notice or the like, the congestion state of the processing processor is prevented.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an ATM communication network in which information to be communicated is divided into fixed length cells and transferred.
The present invention relates to an input traffic control method for regulating traffic to call control signals on subscriber lines.

0002

2. Description of the Related Art In conventional telephone networks, when a call connection request is generated from a subscriber, a call processing processor in a module accommodating the subscriber connects the call based on the call connection request signal. It was being processed. However, if an organization such as a company is accommodated in a module, the module
Since almost all of the subscribers accommodated in a module belong to a single company, simultaneous calls and broadcast communications occur, causing the call processing processor of that module to become congested. Something happened. FIG. 5 is a connection system diagram of a conventional ATM network. In the ATM network, switching nodes 800, 810, 82
Directly connect terminals 806 and 8 to the line accommodation module 801 in
11,823 is connected to the subscriber line multiplexing device 805.
, 815, 525 to a plurality of terminals 807, 808,
812, 813, 821, and 822 are connected. Inside the switching nodes 800, 810, 820, there is a line accommodation module 801 accommodating subscribers and other switching nodes 81.
Line accommodation module 803,80 connected to 0,820
4 are connected to each other in a line accommodation module interconnection mechanism 802. FIG. 4 is a conceptual diagram of module connections when a simultaneous call occurs in the related art. As shown in FIG. 4, a line accommodation module 401 accommodates the line group of company A, and another line accommodation module 402 accommodates the line group of company B. Each of these line accommodation modules 401 and 402 is connected to a line accommodation module interconnection mechanism (self-routing switch section) 4.
It is connected to 03. Now, in order to transmit information to many destinations at the same time, the subscribers of company A are making simultaneous calls or broadcasting communications, and if call connection requests occur frequently, The call processing processor that has been connected to the call processing system becomes congested, and as a result, it is also difficult to execute processes other than call connection processing, such as test diagnosis processing and billing processing. In addition, as a method for regulating input traffic in conventional ATM exchanges, for example, Japanese Patent Application No. 1982
There is a proposal described in the -3156 specification and drawings. According to this, traffic is regulated by monitoring the cell flow of input traffic after a call is set up.

0003

Conventionally, in order to avoid the congestion state shown in FIG. , 402,
Generally, methods have been used to prevent traffic from concentrating on a specific module. However, it is difficult to estimate traffic characteristics in advance. In addition, even if the line is distributed and accommodated in different line accommodation modules,
As the traffic load temporarily concentrates on one of the line accommodation modules due to changes in traffic input conditions, the call processing processor of that module becomes congested and is unable to perform processing other than the above-mentioned call connection processing. There was also the possibility that it would cause problems. After all, due to changes in the traffic characteristics of the subscribers to be accommodated, it is always assumed that the station building will have to be reaccommodated again. Therefore, the maintenance work required for these measures increases, which poses an obstacle in terms of maintainability. An object of the present invention is to prevent processing capacity from overflowing even when temporary call connection requests such as broadcast communications or simultaneous calls occur frequently, and to prevent call connection processing and other processes from being hindered. It is an object of the present invention to provide an input traffic control method that avoids the occurrence of problems and eliminates the need for work for reaccommodating subscribers.

0004

[Means for Solving the Problems] In order to achieve the above object, the input traffic control method of the present invention provides
In a control method for an ATM switch that performs exchange processing of TM multiplexed line data, call control cells are assigned to cells sent from terminals by identifying virtual path numbers and virtual channel numbers within the cells. The number of call connection request frame signals obtained by separating a call control cell or a plurality of call control cells and arriving at an ATM switch is counted, and the arrival density is determined in advance. If it is detected that the specified value has been exceeded, when a subsequent call connection request frame signal arrives, the call processing processor The feature is that the frame signal for requesting call connection is discarded without being handed over to the terminal, and a frame for instructing disconnection or refusing to accept the call is returned to the terminal.

[0005]

[Operation] In the present invention, the signal processing section constantly monitors the arrival density of call connection request frames, and the arrival density of call connection request frames transmitted from the transmitting terminal is determined by a predetermined standard. If the value exceeds the value, the signal processing unit does not hand over the newly arrived call connection request frame to the call processing processor, and instead issues a call connection control function to instruct disconnection or refuse to accept the call. A frame is created and this call connection control frame is sent back to the transmitting terminal. In an ATM network, all call control information or user data information is decomposed into fixed-length blocks called cells, and call control cells are assigned specific virtual path numbers and virtual channel numbers to move through the switched network. Since the call connection control cell is transferred, it is easy to identify the call connection control cell within the line accommodation module. The present invention is a control method that utilizes the features of this ATM exchange communication system. Here, the terms used in the present invention will be defined. A call control cell generally refers to a control information cell related to the occurrence of a call, such as connection or disconnection of a call. Generally, in order to perform call connection processing, a signal processing section is provided in the exchange for reassembling the frames divided into the call connection control cells. Usually, the call connection control cell is
In the signal processing section in the line accommodation module, the frame is processed again.
If the frame is related to call connection processing, it is delivered to the call processing processor within that module. In the present invention, even when traffic is temporarily concentrated on a specific line accommodation module, such as when simultaneous calling or broadcast communication occurs, the call processing processor for call control within the module can be activated. The call processor is able to maintain normal switching operations without entering into a congestion condition.

[0006]

Embodiments Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings. FIG. 1 is a configuration diagram of a signal processing section and a call control section showing an embodiment of the present invention. This signal processing section 218,
Call control unit 2 connected to signal processing unit 218 via a bus
19 are both provided within the line accommodation module. 201 is a cell separation unit for call control, and 215 is a line accommodation module coupling device. In addition, 20 in the signal processing section 218
3 is a frame assembly section, 202 is a cell disassembly section, 210
is a buffer memory, 211 is a layer 2 processing unit, and 2
14 is a congestion control unit. 204 in the congestion control unit 214
205 is a clock generator, 206 is a counter, 207 is a register, 208 is a congestion detection unit, and 209 is a call rejection/disconnection frame generation unit. Further, the call control unit 219 includes a call processing processor 212 and a memory 213. As shown in FIG. 1, a cell arriving at a line accommodation module is assigned a virtual path number (Virtual Path Identification) by the call control cell separation unit 201.
r:VPI) and virtual channel number (Virtual
The cell is separated into a call control cell and a user information cell by referring to the channel identifier (VCI). Among these, the user information cell is transferred to the line accommodation module coupling device 215 and switched to the target route. On the other hand, the call control cell is constructed by the frame assembling section 20.
Transferred to 3. The cells transferred to the frame assembling section 203 are assembled into a frame according to the following procedure. That is, each cell is based on CCITT Recommendation I. It is assumed that the format is compliant with H.361. Multiple cells are combined to create an ATM adaptation layer (CC).
ITT Recommendation I. 362, I. After passing through the cell assembly function of 363), it is assembled into a frame format defined by LAPD. The information field within the frame defined by this LAPD makes it easy to identify that this frame is a frame requesting connection of a call. Note that in an ATM switch, the virtual channel number used for call control is usually assigned a specific channel number that is different from the virtual channel number for main information assigned by the switch when a call is set up. Therefore, on the exchange side, the virtual channel number for main information and the channel number for call control can be easily identified. The frame assembled by the frame assembling section 203 is written into the buffer memory 210, delivered to the layer 2 processing section 211, and read out from the processing section 211 and processed.

[0007] The call connection request frame determination unit 204 of the congestion control unit 214 then determines the frame specified by LAPD.
Based on the information field in the frame, it is determined whether this frame requests connection of a new call or not, and the determination result is output as a signal of call connection request determination output 217. At the same time, this frame is sent to the call acceptance rejection/disconnection frame generation section 209. The output signal 217 of the call connection request frame determination unit 204 is '1' if the frame is for a call connection request, and '0' if the frame is for other call connection control frames. ' is shown. If this frame requests connection of a new call, 1 is added to the value of counter 206. However, when the value of the counter 206 is the upper limit value, it is not added. The value of the counter 206 is subtracted by 1 by a timing pulse generated by the clock 205 at a constant cycle. However, when the value of the counter 206 is 0, it is not subtracted. As a result, the value of the counter 206, which changes from moment to moment, represents the arrival density of call connection request frames at that time. When the arrival density of call connection request frames exceeds a predetermined threshold value indicated by the value of the register 207, the control line 216, which is the output of the congestion detection unit 208, becomes '1' and the call connection request frames are transferred to the buffer memory. By prohibiting writing of the call connection request frame, the call connection request frame is discarded without being handed over to the call processing processor. In addition, the call acceptance rejection/disconnection frame generation unit 20
9, a call connection control frame for instructing refusal to accept the call is created and sent back to the calling terminal via the cell disassembly section 202. In this manner, when the arrival density of call control request frames is high, the congestion control unit 214 executes congestion control without handing over call connection request frames to the call processing processor. Even when traffic is concentrated on a specific switching module, it is possible to prevent the switching equipment from becoming congested without having the call processor make a decision as to whether or not to perform congestion control.

FIG. 3 is a flowchart showing the operation procedure of the congestion control section in FIG. The specific procedure of the congestion control unit 214 is as follows. In the register 207, a threshold value for call occurrence density is set in advance by call processing software (step 101). Congestion detection unit 208
When the call connection request frame arrives (step 102),
The counter value is updated (step 111), and the counter 20
The value of 6 is compared with the value held in the register 207 (step 103), and if the former is smaller than the latter, (
Step 104), determining that no congestion has occurred, and '
0' is sent to the output line 216, and the buffer memory 210 is set to a state in which it can receive this call connection request frame (step 105). If the former is larger than the latter, it is determined that there is a congestion state and outputs '1', thereby prohibiting the buffer memory 210 from receiving the call connection request frame (step 106). At the same time, a frame generation section for instructing call acceptance/disconnection frame generation section 209 to be operable is set (step 107). On the other hand, the call connection request frame assembled by the frame assembly section 203 is temporarily stored in the buffer memory 210 (step 105). In that case, the buffer memory 210 receives the output signal 2 of the congestion detection unit 208.
Based on the logical negation of step 16, it is determined whether to prohibit or accept storage. That is, by looking at the output signal of the congestion detection unit 208, if the value is '0', the buffer memory 2
10 receives and processes the call connection request frame, and when it is ``1'', discards the call connection request frame. Buffer memory 2
The call connection request frame output from 10 is subjected to layer 2 processing in layer 2 processing section 211 (step 1).
09) and is passed via the bus to the call processing processor 212 (step 110). When the call connection request frame stored in the buffer memory 210 is discarded,
In the call acceptance rejection/disconnection frame generation unit 209,
A call connection control frame for instructing rejection of acceptance is generated (step 107), and the cell disassembly unit 202 references the corresponding VPI and VCI to generate a call connection control frame for controlling the call connection control frame. The frame is converted into a cell, and the call control cell is returned to the call connection request frame transmitting terminal (step 108).

[0009] In this embodiment, when a disconnection request frame among the call control frames is received by the line accommodation module, the disconnection request frame is processed by the layer 2 processing unit 211. After that, the call processing processor will perform the disconnection process. In addition, the call connection request determination unit 204
When a disconnection request frame is detected, the call acceptance rejection/disconnection frame generation unit 209 is immediately activated and a disconnection confirmation frame is sent to the calling terminal, so that the layer 2 Processing unit 211 and call processing processor 21
It is also possible to perform this call processing without using 2. Furthermore, in this embodiment, when communicating between each terminal and the exchange, it is assumed that a communication link has already been established, but if a communication link has not been set up, the This can be handled by performing the same procedure as for establishing a link, for example, a link setup request from the terminal side using SAMB, link setup using a UA response from the exchange side, etc.

FIG. 2 is a block diagram of a signal processing section and a call control section showing another embodiment of the present invention. In the embodiment shown in FIG. 2, the traffic control of the present invention can be applied to frames for which layer 2 processing has been completed. In this embodiment, the congestion control section 312 is not provided with a call connection request frame determination section, nor is it provided with a call acceptance rejection/disconnection frame generation section. and,
A layer 2 processing section 30 is installed directly after the frame assembly section.
3 is provided, and a call control frame generation section 315 is activated by an instruction from the layer 2 processing section 303 to generate a call acceptance refusal/disconnection frame and send it back to the terminal. Cells arriving at the line accommodation module are separated into call control cells and users in the call control cell separation unit 314 by referring to the assigned virtual path number (VPI) and virtual channel number (VCI). Separated into information cells. The separated call control cells are transferred to the signal processing block 311, and the user information cells are transferred to the line accommodation module coupling device. The frame assembly section 302 of the signal processing section 311 assembles the arrived control cells into a frame. The assembled frame is subjected to layer 2 processing in a layer 2 processing section 303. The layer 2 processing unit 303
If the content of the frame is a call connection request frame, the congestion control unit 3
The call connection request frame is delivered to the call control unit 313 via the buffer 308 of 12. In this embodiment, in order to prevent the call processing processor 309 from falling into a congestion state, the density of the number of call connection request frames that arrive after the layer 2 processing is performed in the layer 2 processing unit 303 is monitored, The feature is that it is determined whether or not to pass the frame to the call control unit 313.

The congestion control section 312 constantly monitors the number of call connection request frames among the call control frames passed from the layer 2 processing section 303 to the call control section 313, and The value of the counter 307 is incremented before the time frame is passed from the layer 2 processing unit 303 to the call control unit 313. However, if the value of the counter 307 is the upper limit,
Not added. Further, the value of the counter 307 is subtracted by a clock pulse of a constant period generated from the clock 304. However, if the value of the counter 307 is 0, it is not subtracted. The value of the counter 307 represents the density of the number of call connection request frames among the frames passed from the layer 2 processing section 303 to the call control section 303. The congestion detection unit 306 compares the value of the counter 307 with the value of the register 305 that holds a preset call occurrence density, and when the former is greater than the latter, it determines that there is congestion and rejects the connection request. Buffer 30 for frame signal creation
8 will be notified. In addition, in a normal case where congestion does not occur, the layer 2 processing unit 303 sends a message to the call processing processor 30.
Before passing the call connection request frame to 9, the contents of the frame are stored in buffer 308. That is, only when congestion is not detected by the congestion detection unit 306, the call processing processor 309 is notified of a call connection request, and the contents of the buffer 308 are transferred to the memory 310. Conversely, the congestion detection unit 30
6 notifies that congestion has occurred,
Without notifying the call processing processor 309, the call control frame generation unit 315 immediately generates a call acceptance rejection or disconnection frame, and the cell disassembly unit 301 converts the VPI,
By referring to the VCI, the rejected or disconnected frame is converted into a cell, and the cell is returned to the call connection request frame transmitting terminal. In addition, a method for regulating input traffic in the conventional ATM switching system (Japanese Patent Application No. 62-31
It is also possible to share the circuit for monitoring the flow of call traffic (see the '56 specification and drawings) with the present invention.

0012

[Effects of the Invention] As explained above, according to the present invention,
By simply providing a congestion control unit with a simple configuration, even when traffic is temporarily concentrated on a specific line accommodation module, such as when making simultaneous calls or broadcasting, calls for call control within the module can be controlled. without congesting the processing processor.
It is possible to have the call processing processor perform normal switching processing.

[0013]

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an input traffic control system showing one embodiment of the present invention.

FIG. 2 is a block diagram of an input traffic control system showing another embodiment of the present invention.

FIG. 3 is an operation flowchart of the congestion control section in FIG. 1;

FIG. 4 is a conceptual diagram of the connection of accommodation modules when a simultaneous call occurs in the related art.

FIG. 5 is a diagram showing the relationship between an ATM network and a line accommodation module.

[Explanation of symbols]

201, 314 Cell separation unit 215 for call connection control
Line accommodation module coupling device 218, 311 Signal processing section 219, 313 Call control section 202, 301 Cell disassembly section 203, 302 Frame assembly section 211, 303
Layer 2 processing unit 209, 315 Call control frame generation unit, call acceptance rejection/disconnection frame generation unit 204 Call connection request frame determination unit 205, 304 Clock 206, 307 Counter 208, 306 Congestion detection unit 210, 308 Buffer memory 214, 312 Congestion control section 212, 309 Call processing processor 213, 310 Memory 219, 313 Call control section 401, 402 Line accommodation module 403 Line accommodation module interconnection mechanism 404, 405 Line bundle

Claims (1)

[Claims] Claim 1. A method for controlling an ATM switch that performs exchange processing of ATM multiplexed line data on a subscriber line, in which a virtual path number and a virtual channel within the cell are transmitted from a terminal. A call control cell and a user information cell are separated by identifying the numbers, and a call connection request frame signal obtained by assembling the call control cell or a plurality of call control cells is sent to the ATM switch. The number of arrivals is counted, and if it is detected that the arrival density exceeds a predetermined value, when subsequent call connection request frame signals arrive, the call connection request frame signal is without passing the system signal to the call processing processor that performs call switching processing.
An input traffic control method characterized in that the call connection request frame signal is discarded and a disconnection instruction or a frame for refusing call acceptance is sent back to the terminal.