KR960009476B1 - Congestion control according to the congestion generated position in the fully distributed atm switch - Google Patents

Abstract

None.

Description

Congestion control method according to the location of congestion in fully distributed A.M.M exchanger

1 is a block diagram of a call control block in a fully distributed ATM switch system to which the present invention is applied.

2 is a flow chart of preventive congestion control at the entrance of the ATM switch network according to the present invention.

3 is a flowchart of a congestion control of a node in which congestion has occurred according to the present invention.

4 is a congestion control flowchart of congestion detection and release according to the present invention.

* Explanation of symbols for main parts of the drawings

1: SCDC (System Call Data control)

2: Calling party number translation block (NTC)

3: SRSC (Self-Routing Switch Control)

4: Call Admission Control (CAC)

5: Subseriber Call Control

6: TSC (Trunk Service Control)

7: MCSC (Multi-Connection Service Control)

8: Multi-Party Service Control

9: Global Announcement Service Control (GASC)

10: Global Multi-Connection Service Control

11: Global Multi-Party Service Control (GMPSC)

12: GCLSC (Global connection Less Service Control)

13: CGC (ConGestion Control)

The present invention provides a completely distributed ATM switch for controlling congestion in order to continuously and stably provide a service required from a subscriber station among traffic control functions to be performed at each node of an exchange in an ATM exchange. It relates to a runaway control method according to the location of the runaway.

ATM (Asychrouous Transfer Mode) technology exchanges material information with various attributes by unit of 53 octets of cells and by virtual circuits based on logical channel numbers assigned to links between nodes in call determination through statistical multiplexing. It operates at a line speed of more than 155.52Mb / s by changing the network at high speed. Therefore, it is desirable that the system configuration is designed to be easy to structure and control while satisfying various communication requirements.

The services provided in ATM environment show various traffic characteristics such as maximum generation rate and average generation rate of information, burst index, average length of burst intervals, and so the ATM network provides efficient operation of network resources and service quality requirements. There is a need for highly effective traffic control techniques, such as predicting traffic changes and preventing congestion. Therefore, the robust control of congestion control function to prevent the congestion and minimize the effect of congestion when congestion occurs by performing traffic control functions such as call admission control and priority control for the flow of call and information continuously from the entrance of the network to the completion of the call. It needs to be done.

By the way, the existing call processing technology mainly uses voice and low-speed data processing to control the time when the congestion occurs in the network, but in the modern society, high-speed data communication, stop There is a demand for a communication network in which high-speed communication services including video and dynamic video transmission services are provided. In order to satisfy the demands of such communication services, an ATM exchange technology for processing various traffic types is being studied.

The present invention devised to meet the above requirements is performed in a call control block for determining a congestion occurrence position and a method for controlling congestion occurrence in order to prevent and control a congestion state of an exchange in order to satisfy a service request of a user in an ATM exchange. In order to prevent and control the occurrence of congestion, the control at the network entrance according to the congestion control part, the control method to be performed by the control unit of the congestion generating switch node, the control in the network and the congestion control according to the congestion location for determining the congestion status The purpose is to provide a method.

In order to achieve the above object, the present invention, SCDC (System Call Data Control), Calling / Calling Number Translation Block (NTC), Self-Routing Switch Control (SRSC), Call Admission Control (CAC), Subseriber Call Control (SCC) , Trunk Service Control (TSC), Multi-Connection Service Control (MCSC), Multi-Party Service Control (MPSC), Global Announcement Service Control (GASC), Global Multi-Connection Service Control (GMCSC), Global Multi-Party In a congestion control method applied to an ATM switch having Service Control (GCLSC), Global Connection Less Service Control (GCLSC), and Con Gestion Control (CGC), A first step of determining whether or not the traffic is matched by comparing and analyzing the received signaling data with system call control data when meta signaling is processed from a matching function and a call control request is input to the SCDC block; After performing the first step, if the reported traffic characteristics match, the corresponding route connection procedure is performed and terminated. If the reported traffic characteristics differ, the transmission of the cell into the network is delayed to match the buffering at the network entrance. A second step of checking whether the traffic characteristics match again; After performing the second step, if the characteristics do not match, discard the cell to suppress transmission to the network; if the matched traffic characteristics, perform the corresponding path connection procedure and terminate the third step; In the case of congestion control of a congested node, when a congestion is detected, a network control signal is sent from the congested node to an input node of a power switch, and the node receiving the control signal delays the average cell transmission rate to increase the duration of congestion. Analyzing and investigating whether the analysis lasts longer than a prescribed time; After performing the fourth step, in case of momentary congestion, a normal function is performed by a buffer on the routing path between the subscriber terminal and the congestion generating node. If the congestion state lasts more than a predetermined time, the control signal is transmitted to the subscriber terminal along the reverse path. A fifth step of reducing the transmission speed of the sending terminal to stop the congestion state and to stop the congestion and release the congestion; A sixth step of measuring and analyzing bandwidth usage by detecting and releasing congestion to measure and compare a service request bandwidth of a predetermined section and a service request bandwidth of a previous section; A seventh step of determining whether the congestion is performed after performing the sixth step, by comparing the service success rate of the current predetermined section and the service success rate of the previous section; And performing the service control function for the congestion control after the seventh step, and continuously performing the service failure rate until the service failure rate falls below a certain value. When the service is performed in the normal state, the eighth step of easing and releasing the congestion control is performed. It is characterized by comprising.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

1 is a block diagram of a call control block in a fully distributed ATM switch system to which the present invention is applied, and the hardware configuration basically performs a connection function between an access switching module (ASM) and an ASM that performs a dotted line function. Has a modular structure consisting of a Central Interconnection Module (CIM).

ASM can operate independently with minimal system configuration. In large systems, many ASMs operate as concentrators with constant concentrating ratios, and CIM is a dismantled wkd value for large systems. It works for maintenance. The call control block, which is a software block implemented in ASM, is completely distributed in ASM in order to maintain stable service with minimal impact on subscribers when system failure occurs. When signaling is handled and the message is transmitted to the SCDC block of call control, the SCDC block compares the data of each user group with the data of the system and then NTC for number translation. The message is sent to the block, and the NTC (2) block translates the calling / called number, and the SRSC block notifies the number translation result to the SRSC (3) block. Input / output header data in the matching module or relay line matching module is analyzed, and the band is allocated from the CAC (4) block. eriber Call Control (5) block, TSC (Trunk Service Control) (6) block for other stations, and multi-connection service control (MCSC) (7), MPSC (Multi-Party Service) Control (8), Global Announcement Service Control (GASC) (9), Global Multi-Connection Service Control (GMCSC) (10), Global Multi-Party Service Control (GMPSC) (11), Global connection Less Service Control (12) Notifies the block to receive the corresponding resource to perform the unique function of each block.

If the call control function becomes difficult due to congestion of system or resources during the function of each block, SRSD, CAC, CGC (ConGestion Control) block 13 interlocks to block incoming or outgoing calls according to the class of the caller. Responsive congestion control functions such as blocking.

FIG. 2 is a flow chart of an exemplary congestion control at the network inlet according to the present invention, in which meta signaling is processed from the matching function (14) and a call request is input to the SCDC block (1). It consists of the current payload with the maximum transmission rate of cells / second and transmits signals to the SCDC block 1 by allocating, removing and checking signaling virtual channels, and the SCDC block 1 receives the received signaling data. By comparing and analyzing the system call control data (15), the traffic occurrence status from the caller is monitored and if the reported traffic characteristic (16) matches, the corresponding route connection procedure is performed (17). (18) Delay transmission of Sal into the network to be consistent by buffering at the network entrance (19) and if it still does not match the characteristics (20) discard the cell (21) The transmission is suppressed. That is, when the call is called, the service class and traffic characteristics indicating the allowable cell discard rate, average transmission delay, and dispersion, which are required quality of the call, are compared and analyzed to suppress the congestion occurrence factor.

FIG. 3 is a flow chart of a congestion control flow of a congested node according to the present invention, and a link layer response control method using a back-pressure method between congested nodes by sending a control signal from a congested node to a previous node. In order to prevent the service quality of the virtual channels (VCCs) in the link from being significantly degraded due to cell loss caused by the congestion in the buffer of each output link due to the traffic overload, the in-network controller also controls the congestion. When the congestion is detected (22), the control unit interacts with the priority control function to analyze whether the output channels cause cell loss above a certain value, and to control the source that does not satisfy the quality of service condition due to the cell loss. Performs transmission and reception of control signals. When congestion occurs at a specific node of an ATM switch, it sends a suppression signal backward through the switch to control the source channel of the congestion, and transmits that the specific node is congested to suppress the transmission speed. For VC, the network control 23 signal is sent from the node where the congestion has occurred to the input node of the power switch. In the node receiving the control signal, the average cell transmission rate of the corresponding VC / VP is reduced (24). In case of instantaneous congestion, the node receives the control signal to function as a normal function by the buffer on the routing path between the subscriber terminal and the congestion generating node. Analyzing (25) if the congestion condition lasts longer than the prescribed time (26), control signal 27 is sent along the reverse path to the subscriber terminal to reduce the transmission speed of the terminal to stop the congestion state (28) to mitigate congestion (29) ), The cell is discarded (31) if the runaway condition persists for more than the prescribed time (31). In addition, even if it is released within the specified time, the runaway condition is continuously analyzed and if the runaway occurs again, the runaway duration is analyzed again.

4 is a flowchart for detecting and releasing congestion according to the present invention. In order to quickly start the congestion control function when congestion occurs, it is necessary to detect congestion state within a short time. However, if the detection time is made too short, an unnecessary runaway control function may be started. Even if the actual congestion occurred, it may not be in the congestion state in the unit time period.In addition, the detection time and the load may be detected in order to detect the congestion accurately and in a short time since the system may be further loaded by the start of the congestion control function. Accurate analysis of the condition is required. Measures and analyzes the usage of the system with data continuously monitoring the cell discard rate, transmission delay time, and transmission standby cell in the buffer (32), and the service request bandwidth of the current section (33) and the service request bandwidth of the previous section (34). ) By comparing the service success rate (35) of the current section, and the service success rate (36) of the previous section to determine whether the congestion (37). A congestion determination considers the CPU occupancy status of each processor, a traffic control point of view, while greater than the current section of the service request for capacity (B _n) the rental capacity requirements of the previous section Services (B _p) service success rate of the current section ( If S _n ) is less than the service success rate (S _p ) of the binary section, it is determined to be congestion and performs the service control function for the congestion control 38 at the level of incoming and outgoing call, incoming call, and call signal.

The congestion monitoring is continuously performed until the service failure rate falls below a certain value (39), and when the service is performed in a steady state, the congestion control is relaxed (40) and released (41). In addition, if the runaway control is continued for a long time, the use efficiency of the network is reduced, but if it is released before the runaway is finished, the runaway state is reached again. Therefore, release of runaway should be repeatedly performed gradually through several steps. As a judgment of relaxation and release, the runaway generation parameter is monitored and determined. In other words, if the congestion is caused by cell transmission delay, it monitors and analyzes centering on cell transmission delay.In case of insufficient bandwidth, the cell flow rate of VP should be observed and released.However, for VPs connected with expected statistical multiplexing effect, Since it may not be possible to anticipate the maximum number of cells at one time, it must be done with more detailed steps than in regulation.

In addition, when accurate observation is performed at each step, the judgment reservation time for a certain unit of time must be passed in order to determine the instantaneous load bias and the instant congestion.

Accordingly, the present invention as described above provides a congestion control method that is easy to add the future function by performing the congestion control by each congestion generation function node, and improve the quality of system service by accurate determination of congestion to realize a stable traffic function To contribute to.

Claims (1)

SCDC (System Call Data Control) (1), Call / Date Number Translation Block (NTC) (2), Self-Routing Switch Control (SRSC) (3), Call Admission Control (CAC) (4), Subseriber Call Control (5), Trunk Service Control (TSC) (6), Multi-Connection Service Control (MCSC) (7), Multi-Party Service Control (MPSC) (8), Global Announcement Service Control (GASC) (9) , Global Multi-Connection Service Control (GMCSC) 10, Global Multi-Party Service Control (GMPSC) 11, Global Connection Less Service Control (GCLSC) 12, and ConGestion Control (CGC) 13. In the congestion control method applied to an ATM switch, in the case of preventive congestion control by user preference, meta signaling is processed from a matching function and a call control request is sent to the SCDC block. A first step of comparing the received signaling data with system call control data to determine whether or not the traffic is identical; After performing the second step, if the reported traffic characteristics match, the corresponding route connection procedure is performed and terminated. If the reported traffic characteristics differ, the transmission of the cell into the network is delayed to match by buffering at the network entrance. A second step of checking whether the traffic characteristics match again; After performing the second step, if the characteristics do not match, discard the cell to suppress transmission to the network; if the matched traffic characteristics, perform the corresponding path connection procedure and terminate the third step; In the case of congestion control of a congested node, when a congestion is detected, a network control signal is sent from the congested node to an input node of a power switch, and the node receiving the control signal delays the average cell transmission rate to increase the duration of congestion. Analyzing and investigating whether the analysis lasts longer than a prescribed time; After performing the fourth step, in case of instantaneous congestion, the function is normalized by the buffer on the routing path between the subscriber terminal and the congestion generating node. If the congestion state lasts more than a predetermined time, the control signal is transmitted to the subscriber terminal along the reverse path. A fifth step of reducing the transmission speed of the sending terminal to stop the congestion state and to stop the congestion and release the congestion; A sixth step of measuring and analyzing bandwidth usage by detecting and releasing congestion to measure and compare a service request bandwidth of a predetermined section and a service request bandwidth of a previous section; A seventh step of determining whether the congestion is performed after performing the sixth step, by comparing the service success rate of the current predetermined section and the service success rate of the previous section; And performing the service control function for the congestion control after the seventh step, and continuously performing the service failure rate until the service failure rate falls below a predetermined value, thereby easing and releasing the congestion control when the service is performed in a normal state. Congestion control method according to the runaway location of the fully distributed A.M.M (ATM) exchanger comprising a.