KR20010060693A - A method of preventing loss for realtime traffic in atm exchange - Google Patents

Abstract

PURPOSE: A method for preventing the loss of real-time traffic data in an ATM exchange is provided to effectively utilize the traffic capacity of a port by disposing of a non-real-time service only in case that the traffic of a real-time service reaches the maximum traffic of a relevant port. CONSTITUTION: If a traffic congestion state is generated at a specific output port among the plural output communication ports of an ATM exchange switch part(S110), the congestion state is reported to the CPU of an ATM exchange(S120). The CPU gradually diminishes the bandwidth or transfer rate of a non-real-time service connected to the output port(S130). Monitoring the output port, the CPU judges whether the output port has got out of the traffic congestion state(S140). If it is judged that the output port has got out of the traffic congestion state, the CPU gradually recovers the diminished bandwidth or transfer rate of the non-real-time service(S150). Then the CPU judges whether the output port keeps a normal state(S160).

Description

A METHOD OF PREVENTING LOSS FOR REALTIME TRAFFIC IN ATM EXCHANGE}

According to the present invention, when the amount of data signals for transmission applied to a specific switching port in an Asynchronous Transfer Mode (ATM) exchange exceeds the data signal transmission limit or bandwidth of the corresponding switching port, that is, the traffic When the traffic volume is congested, the data of the real time service traffic is reduced by reducing the data transmission speed or bandwidth of the non-real time service applied to the corresponding switching port. A method of preventing loss or loss.

In a digital data transfer exchange, a synchronous transfer mode that does not use a synchronous signal transmits much more than a synchronous transfer mode that uses a synchronous signal as a method of improving the data transfer rate. Speed is fast and efficient.

In the asynchronous transmission mode (ATM) as described above, since the transfer rate of data is fast or the bandwidth is wide, that is, it can handle a lot of traffic, it is necessary to use one communication port. By using this method, data of several channels can be simultaneously transmitted.

As described above, in an ATM switch for switching a communication port of an asynchronous transmission mode (ATM), when traffic is temporarily concentrated on a specific port, data is transmitted only in a bandwidth range where data transmission of the corresponding port is possible. Becomes

In addition, the kind of service that can be used in the asynchronous transfer mode (ATM) exchange as described above is a real time service and a line or a path that occupies a line or a connection path in real time. There are two types of non-realtime services that do not need to be occupied in real time, and the line occupancy fee of Realtime Service is higher than the line occupancy fee of Non Realtime Service. do.

Hereinafter, a method of preventing real-time traffic loss of an asynchronous transmission mode switch according to an embodiment of the prior art will be described with reference to the accompanying drawings.

1 is a functional block diagram of a general asynchronous transfer mode exchange, FIG. 2 is a state diagram of traffic imposed on a port of an asynchronous transfer mode exchange, and FIG. 3 is a real time view of an asynchronous transfer mode exchange according to an embodiment of the prior art. How to prevent traffic loss is a flowchart.

Referring to the accompanying drawings, the asynchronous transfer mode (ATM) exchange shown in Figure 1, the first to N-th subscriber reception matching unit that is interfaced with a plurality of callers to transmit data (authorized data) (11,12,13)

First to N-th subscriber transmission matching units 41, 42, 43 for interfacing with a plurality of called parties receiving data and outputting data;

A switch unit 20 connected to the plurality of subscriber reception matching units 11, 12, 13 and the plurality of subscriber transmission matching units 41, 42, 43 to switch a data transmission path;

And a central processing unit 30 connected to the switch unit 20, the plurality of subscriber receiving matching units 11, 12, 13, and the subscriber transmitting matching units 41, 42, 43 to monitor and control functions.

In the asynchronous transfer mode (ATM) switch, a plurality of switching ports may transmit data at a transfer rate or a bandwidth of 155 Mbps as an embodiment, and FIG. The state diagram showing a threshold by the amount of traffic applied to the bandwidth of the same switching port is shown.

The real-time traffic loss prevention method according to the prior art in the asynchronous transfer mode (ATM) switch as described above, the traffic that the data of the upper limit (Upper Limit) is applied to any one port of the communication port of the switch unit 20 A first step (S10) of determining whether a runaway phenomenon occurs;

A second step (S20) of notifying the central processing unit 30 of a corresponding state when traffic is congested on a specific port in the first step (S10);

In the second step (S20), when the notification that the traffic is congested to a particular port, the central processing unit 30 matches the plurality of subscriber reception matching the path to the corresponding port (Port) that the traffic is congested The control unit 11, 12, and 13 controls the Cell Loss Priority (CLP), which indicates the data processing priority of the non-realtime service, to be reduced from '0' to '1' as an embodiment. With three steps (S30),

A fourth step S40 of determining whether the traffic of the corresponding port is in a normal state outside the upper limit after the CLP is adjusted downward in the third step S30;

As a result of the determination of the fourth step (S40), when the traffic of the corresponding port is out of the upper limit (Upper Limit), the central processing unit 30 controls the plurality of subscriber reception matching units (11, 12, 13) downward And a fifth step S50 of restoring the adjusted CLP of the non-real-time service to the original CLP value.

Hereinafter, a method for preventing real-time traffic loss in an asynchronous transmission mode (ATM) exchange according to the prior art having the above configuration will be described in detail with reference to the accompanying drawings.

There are two types of services that are switched in an asynchronous transfer mode (ATM) exchange: Realtime Service and Non-Realtime Service. Real-time services are the same as voice data transmission services. And rt-VBR (Realtime Variable Bit Rate) service, which always allocates a constant bandwidth to the ATM switch so that it can process in real time when a voice data transmission request is applied at any time.

The port configured in the switch unit 20 of the ATM switch is a traffic capacity capable of transmitting data of 155 Mbps, and is switched and applied to transmit data of the 155 Mbps traffic capacity to a specific port. In the case of the prior art, a traffic congestion is prevented by lowering a cell loss priority (CLP), which is a priority for processing non-real-time service data, but the CLP of the real-time service data has the same CLP value as the non-real-time service data. There is a problem that even the data of the real-time service is lost, discarded or lost.

In the asynchronous transfer mode (ATM) exchange of the prior art operating as described above, the real-time traffic loss prevention method, the switch unit 20 of the ATM exchange monitors each output port (Port), each output port is processed Data transmission capacity that can be, in one embodiment, if the current traffic volume within the 155 Mbps transmission capacity reaches a constant upper limit, it is determined that the traffic is congested on the corresponding port (S10), the center The processing unit 30 is notified of the state (S20).

The central processing unit 30 searches for a plurality of related input ports for transmitting data to a corresponding output port in which traffic is congested. Non-real time serviced by the subscriber reception matching unit 11, 12, 13 by applying a control signal to the plurality of subscriber reception matching units 11, 12, 13 respectively connected to the plurality of input ports and transmitting data. (Non Realtime) The CLP, which is a transmission processing priority of the service data, is lowered, that is, the non-real-time service having the CLP of '0' is lowered to the CLP of '1'.

Accordingly, since the output port in which the traffic is congested transmits from real time service data having a CLP value having a high data transmission priority, non-real time service data having a low priority is discarded or lost.

The central processing unit 30 checks again the traffic of the corresponding output port through which the traffic congested through the switch unit 20 to determine whether the traffic continues to exceed the upper limit threshold or whether the traffic is in a normal state. If the traffic of the upper limit threshold, the down-regulated CLP value of the non-real-time service is maintained as it is, if it is out of the traffic of the upper limit threshold, the down-adjusted CLP value of the non-real-time service is recovered (S50) and ends.

However, the real-time traffic loss prevention method of the ATM switch according to the prior art, because the data is transmitted or lost according to the priority level of the data transmission, the subscriber can not process the data, effective control over traffic congestion Because of this, there was a problem of inefficiently operating the traffic capacity of the port.

According to the present invention, in the asynchronous transmission mode switch, as the amount of traffic applied to the data transmission switching port increases, the transmission rate or bandwidth of the non-real time service to use the corresponding port is flexibly adjusted, and the traffic of the real time service is changed. The purpose of the present invention is to provide a method of effectively utilizing the traffic capacity of a port by discarding or losing the non-real-time service only when the maximum traffic amount of the corresponding port is reached.

In order to achieve the above object, the present invention provides a process for notifying a central processing unit by determining whether a traffic congestion occurs above a threshold value in a specific switching port of an asynchronous transmission mode switch, and a switching port in which the traffic congestion occurs. A process of analyzing the connection information connected to the terminal; and notifying the subscriber receiving matching unit from the central processing unit to lower the bandwidth from the lowest priority of the non-real time connection information according to the analysis result of the process; The connection of the subscriber reception matching unit receiving the received is characterized in that the real-time traffic loss prevention method of the asynchronous transmission mode switch is configured, including the process of lowering the bandwidth.

1 is a functional block diagram of a general asynchronous transfer mode exchange,

2 is a diagram illustrating a traffic state imposed on a port of an asynchronous transfer mode exchange,

3 is a flowchart illustrating a method of preventing real-time traffic loss of an asynchronous transfer mode switch according to an embodiment of the prior art;

4 is a flowchart of a method for preventing real-time traffic loss in an asynchronous transmission mode switch according to an embodiment of the present invention;

5 is a band setting table of a connection according to an embodiment of the present invention.

** Explanation of symbols on the main parts of the drawing **

11, 12, 13: reception matching unit 20: switch unit

30: central processing unit 41, 42, 43: transmission matching unit

Hereinafter, a method of preventing real-time traffic loss of an asynchronous transfer mode switch according to the present invention will be described with reference to the accompanying drawings.

4 is a flowchart illustrating a method for preventing real-time traffic loss in an asynchronous transmission mode switch according to an embodiment of the present invention, and FIG. 5 is a band setting table of a connection according to an embodiment of the present invention.

Referring to the configuration of the asynchronous transfer mode (ATM) exchange has been referred to in the accompanying drawings and the description of the prior art, a method for preventing real-time traffic loss of the asynchronous transfer mode switch according to the technique of the present invention, ATM switch unit 20 A first step (S110) of determining whether a traffic congestion phenomenon in which transmission data reaching an upper limit occurs is applied to any one port among a plurality of output communication ports of the second and second output communication ports;

When the amount of data to be transmitted to a specific output port (Port) of the switch unit 20 in the first step (S110), that is, when the traffic is congested, the traffic congestion state as described above the ATM A second process (S120) of notifying the central processing unit 30 of the exchanger;

In the second step (S120), the central processing unit 30 that is notified from the switch unit 20 that the traffic is congested to a specific output port of the ATM switch to the corresponding output port (Port) that the traffic is congested Search for the corresponding plurality of input ports connecting the data transmission paths, and control the connection of the corresponding subscriber reception matching units 11, 12, and 13 connected to the plurality of input ports, respectively. Bands shown in FIG. 5 are sequentially selected from UBRs having low priorities in terms of a data transfer rate or bandwidth of a subscriber signal receiving non-real time services of 11, 12, and 13). Data over the bandwidth set in the configuration table is discarded using the UPC (Usage Parameter Control) function, and is gradually reduced and adjusted to a predetermined transmission rate or bandwidth allocated to the bandwidth configuration table. 3 process (S130) and,

The central processing unit 30 of the ATM switchboard monitors the output port from which the traffic has been congested to determine whether it is out of the traffic congestion state, and if not, the fourth process of feeding back to the third process (S130). (S140),

In the fourth step (S140), if it is determined that the amount of data to be transmitted by the corresponding output port of the ATM switch unit is congested, that is, the traffic is out of the congested state, it is connected to the output port to transmit data, that is, The control signal is applied to the plurality of subscriber reception matching units 11, 12, and 13 from the central processing unit 30, and the data transmission rate or bandwidth of the non real-time service is determined in the third process ( A fifth step (S150) of recovering only a portion in steps by increasing the predetermined width corresponding to the reverse order of the low priority reduced in step S130 and the bandwidth reduced in steps;

The central processing unit 30 of the ATM switch monitors the corresponding output port of the switch unit 20 to determine whether the traffic state maintains a normal state beyond the upper limit, and the traffic of the corresponding output port. When the state or the traffic processing capacity does not exceed the upper limit threshold, the process returns to the third process S130, and when the traffic state or the traffic processing capacity falls outside the upper limit threshold, the sixth process ends (S160). It is composed of

Hereinafter, a method for preventing real-time traffic loss of an asynchronous transmission mode (ATM) exchange according to the present invention having the above-described configuration will be described in detail with reference to all necessary accompanying drawings.

There are two types of services that are switched in an asynchronous transfer mode (ATM) exchange: Realtime Service and Non-Realtime Service. Real-time services are the same as voice data transmission services. And rt-VBR (Realtime Variable Bit Rate) service, which always allocates a certain bandwidth to the ATM switch, so that any time a voice data transmission request is received from a subscriber, it can be processed in real time. do.

The non-real-time service does not need to be transmitted in real time, such as E-mail, fax (fax), and graphic data transmission service, so that the receiver receives data in real time. There is a slight margin in data transmission time, and there are services such as Non-Realtime Variable Bit Rate (Nrt-VBR), Validable Bit Rate (ABR), and Unspecified Bit Rate (UBR). In Nrt-VBR, ABR, and UBR, UBR has the lowest priority.

Non-Realtime service is not a problem even if the time of data transmission is delayed by a predetermined time, so if the traffic is not congested at the corresponding output port of the ATM switch, it is transmitted in real time. When the traffic is congested, each output of the ATM switching unit 20 is stored by temporarily storing data to be transmitted in a buffer memory and withdrawing the data to the receiver when the traffic conditions improve. The data transmission efficiency of the port can be maximized and operated.

Therefore, such a non-real time service can transmit data after a delay (delay depending on the equipment) for a predetermined time, so that the data transmission capacity or traffic limit of each output port, one implementation For example, it is possible to receive and transmit more data than a traffic transmission capacity of 155 Mbps.

In other words, data is not always transmitted constantly at 155 Mbps. If there are many users, the data may exceed 155 Mbps. If there are few users, the data may not reach the lower limit. In the case of this congestion, the data of non real time service, which is low in usage fee and may transfer the data by delaying the transmission time, is delayed for a predetermined time, and then the data is transmitted at a low time. As a result, the data transfer or processing capacity is increased, and the delay time is different for each ATM switch. However, an ATM switch that sets the delay time too long reduces the user's reliability of the equipment.

However, when the transmission time of the non-real-time service is delayed to increase the data transfer capacity or bandwidth of the ATM switch, that is, when the processing ratio of the non-real-time service is set too high, the data transmission traffic of the real-time service on a specific port is increased. If this increases, the traffic is congested as a whole, and even some data of the real-time service cannot be transmitted and is lost.

In the case of the non-real-time service, in particular, the UBR service is the least expensive to use the line and does not guarantee the success rate of transmission for the transmitted data, but the application that uses the retransmission algorithm (Algorithm) in most ATM exchanges (Application Program is applied, and data that is not transmitted even after the application is applied is discarded or lost.

As described above, in a port to which a non-real time service is applied, a virtually applying a bandwidth higher than a certain level higher than a data transmission speed or a data transmission bandwidth that a corresponding port can transmit, while preventing a loss of traffic of a real-time service, In operation S110, the switch unit 20 of the ATM switch monitors each output port to determine whether traffic of an upper limit that is arbitrarily set for each output port is reached (S110). When the switch unit 20 arrives, the central processing unit 30 notifies the state of the corresponding output port (S120), and the central processing unit 30 receives a plurality of inputs connected to output ports that approach traffic of an upper limit threshold. Search the port and apply a control signal to a plurality of subscriber reception matching units (11, 12, 13) connected, respectively, corresponding non-real time (Non Among the realtime services, UBR, ABR, and Nrt-VBR connection services having the lowest priority (CLP) are sequentially ordered based on the data transmission rate or bandwidth allocated to the bandwidth setting table for each connection as shown in FIG. In step S130, the data is reduced by the UPC (Usage Parameter Control) function and the data over the set and allocated bandwidth is discarded.

In the attached band setting table of FIG. 5, the bandwidth allocated to the areas 'T0' and 'T1' is recorded, thereby setting the size of the bandwidth through the interval between each connection or channel.

After reducing the transmission rate or bandwidth of the non-real-time service by a predetermined criterion by the third process, it is determined whether the traffic of the corresponding output port is out of an upper limit threshold and is in a normal traffic state. Feed back to (S130) (S140).

If the traffic of the corresponding port is out of the congestion state in the fourth step (S140), the central processing unit 30 applies a control signal to the plurality of subscriber subscriber matching units 11, 12, 13, The reduced transmission rate or bandwidth of the non-real-time service is gradually restored or increased based on a predetermined criterion (S150), and the central processing unit 30 monitors the corresponding output port of the switch unit 20 to provide traffic. If it is determined that the steady state is not congested and the runaway is congested, it is fed back to the third process (S130), and if the normal traffic is maintained, the process proceeds to the end step (S160).

In the method of preventing real-time traffic loss of an asynchronous transfer mode (ATM) exchange according to the present invention as described above, when the traffic reaches a predetermined upper limit threshold arbitrarily, the bandwidth of a non real-time service is gradually phased. If the traffic is mitigated and traffic is continuously increased, the real-time service prevents any loss or loss of data while providing traffic. If it decreases, the bandwidth of the non-real-time service is gradually increased to transmit the bandwidth, or the transmission speed of the limited output port can be utilized as efficiently as possible.

In the present invention as described above, when traffic is concentrated and congested at the output port of the asynchronous transmission mode switch, the data transmission rate or bandwidth of the non-real-time service is reduced step by step so that the traffic loss of the real-time service does not occur. There is an industrial utilization effect to improve the reliability of the exchanger and operate by utilizing the transmission speed of the output port to the maximum.

Claims (5)

Determining whether a traffic congestion above a threshold occurs in a specific switching port of an asynchronous transmission mode switch and notifying the central processing unit; Analyzing connection information in which a path is connected to a switching port in which traffic is congested; Notifying the subscriber receiving matching unit from the central processing unit to lower the bandwidth from the lowest priority of the non-real time connection information according to the analysis result of the above process; The corresponding connection of the subscriber receiving matching unit notified by the above process is configured to include a process of lowering the bandwidth, real-time traffic loss prevention method of the asynchronous transmission mode switch. According to claim 1, Real-time traffic loss of the asynchronous transfer mode switch further comprising controlling the CPU to gradually restore the initial bandwidth of the corresponding port when the traffic falls below a threshold value in the specific switching port of the asynchronous transfer mode switch. Prevention method. According to claim 1, The information analysis process may further include the step of receiving a notification that traffic is congested at a specific port of the switching port in the central processing unit, and identifying a corresponding number of subscriber reception matching units connecting a path to the port. A method for preventing real-time traffic loss of an asynchronous transfer mode exchange. According to claim 1, The subscriber reception matching unit manages the band setting table of the connection and communicates with the band set in the band setting table. According to claim 1, The subscriber reception matching unit discards the data of more than the bandwidth set in the band setting table, real-time traffic loss prevention method of the asynchronous transmission mode switch.