KR100239171B1 - Clock Recovery Apparatus and Method of ATM Subscriber Interface Mudule - Google Patents

Abstract

Disclosed is a clock recovery apparatus that processes various resources of a subscriber matching device to be kept in the same state as before the clock was cut when the clock is supplied again after the clock is cut in the ATM switch receiving the clock according to the redundant structure. have. According to the present invention, the monitoring circuit monitors the first clock or the second clock supplied according to the redundant structure and outputs the monitoring result. The recovery unit prepares to initialize the resources of the physical layer processing unit and the ATM layer processing unit when it is monitored by the monitoring circuit that both the supply of the first clock and the second clock are disconnected. The recovery unit initializes the resources of the physical layer processing unit and the ATM layer processing unit when it is monitored that one of the clocks of the first clock and the second clock is restored and supplied.

Description

Clock Recovery Apparatus and Method of ATM Subscriber Interface Device with Clock Supply in Redundancy Structure {Clock Recovery Apparatus and Method of ATM Subscriber Interface Mudule}

The present invention relates to a subscriber matching device of an ATM switch receiving a clock according to a duplex structure. In particular, when a clock is supplied again after cutting the clock, various resources of the subscriber matching device are identical to the state before the clock is cut. The present invention relates to a clock recovery apparatus and a method for processing to be maintained as.

Generally, in an ATM (Asynchronous Transfer Mode) exchange, a subscriber matching device (hereinafter referred to as an "ATM subscriber matching device") receives an ATM cell as an optical signal or an electric signal from a subscriber, and the ATM cell receives the ATM cell through another switch. Performs the transfer to another exchange.

1 is a view showing a connection configuration of an ATM subscriber matching device to which the present invention is applied. The ATM subscriber matching device 20 performs the operation as described above in synchronization with a clock clock applied from the clock distributor 10. At this time, since the clock provided from the clock distributor 10 is dualized with Clock A and Clock B, if the supply of this clock is stopped while supplying Clock Clock A from one clock distributor, for example, 10A, the other clock is divided. Redundant switching capability to accept clock Clock B from device 10B. That is, the clock distributor 10 is designed in a redundant structure to provide a clock for the operation of the ATM subscriber matching device.

FIG. 2 is a diagram illustrating a state diagram of the clock distribution device 10 shown in FIG. 1.

In FIG. 2, state A indicates that clock Clock A is selected and state B indicates that clock Clock B is selected. Numbered arrows indicate events for state transitions. Event 1 represents the event that clock Clock A goes from active to failed when clock Clock B is active. Event 2 represents an event from clock clock B active to truncated when clock clock A is active.

As shown in FIG. 3, the subscriber matching device 20 that receives the clock from the clock distribution device 10 having the redundant structure includes a physical layer processor 22, an ATM layer processor 24, and a controller 26. At this time, the resources of the physical layer processor 22 and the ATM layer processor 24 include first-in first-out (FIFO) and dual port random access memory (DPRAM). The physical layer processor 22 and the ATM layer processor 24 are provided from the clock distributor 10. By inputting the 46MHz clock provided, it is used after generating 19.44MHz, 23MHz, and 12MHz.

As described above, since the clock distribution device for supplying the clock to the ATM subscriber matching device to which the present invention is applied has a redundant structure, the ATM subscriber matching device 20 continues to operate even if one of the clock distribution devices is disconnected. It is effective to maintain.

However, when both clock distribution apparatuses are disconnected, the physical layer processor 22 and the ATM layer processor 24 are in an abnormal state, which greatly affects the resources of the physical layer processor 22 and the ATM layer processor 24. In this case, even when the clock distribution device 10 returns to normal again, abnormal data is already stored in the resources of the physical layer processor 22 and the ATM layer processor 24, and thus the data is not matched with the data for controlling the subscriber device 30 of the switch controller 50. There is a problem in transmitting the incorrectly generated ATM cell to the switch 40 and the switch controller 50.

In order to solve this problem, the ATM switch operator must directly restart the subscriber matching device 20 to recover resources of the physical layer processing unit 22 and the ATM layer processing unit 24 of the subscriber matching device, but this causes a great inconvenience for the operator.

Accordingly, an object of the present invention is to prevent a malfunction of an ATM switch caused by a truncation of a clock supplied to an ATM subscriber matching device.

Another object of the present invention is to maintain the state of the subscriber matching device as it was before the clock was cut when the clock supplied to the ATM subscriber matching device is cut off and then recovered.

Another object of the present invention is to maximize the convenience of operation by eliminating unnecessary restart of the ATM subscriber matching device.

It is another object of the present invention to always keep the data for controlling the ATM switch and the subscriber device and the data of the subscriber matching device the same.

According to the present invention for achieving these objects, the clock recovery device for the subscriber matching device having a physical layer processing unit, ATM layer processing unit and subscriber unit control unit in the ATM switch, the first clock or the second clock supplied according to the redundant structure With monitoring circuitry to monitor and output its monitoring results. When it is monitored by the monitoring circuit that both the supply of the first clock and the second clock are disconnected, the controller prepares to initialize the resources of the physical layer processing unit and the ATM layer processing unit, and again the first clock and the second clock. When any one of the clocks are monitored to be recovered and supplied, the physical layer processing unit and the ATM layer processing unit of the recovery unit for initializing the resources.

According to the present invention, a clock recovery method for a subscriber matching device having a physical layer processing unit, an ATM layer processing unit, and a subscriber unit control unit in an ATM switch includes: monitoring a first clock or a second clock supplied according to a redundant structure and monitoring the result; (A) process of outputting and. (B) preparing to initialize the resources of the physical layer processing unit and the ATM layer processing unit when it is monitored that the supply of the first clock and the second clock is cut off by the monitoring circuit; and (b) After performing the process, if it is monitored that one of the clocks of the first clock and the second clock is recovered and supplied, the process of (c) initializing the resources of the physical layer processor and the ATM layer processor.

1 is a view showing a connection configuration of the ATM subscriber registration apparatus to which the present invention is applied.

FIG. 2 shows a state diagram of the clock distribution device shown in FIG.

3 is a view showing the configuration of the subscriber registration device shown in FIG.

4 is a diagram illustrating a configuration of an ATM subscriber registration device according to the present invention.

FIG. 5 is a diagram illustrating a state diagram of the clock redundancy and recovery unit illustrated in FIG. 4.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, the terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of the user or chip designer, and the definitions should be made based on the contents throughout the present specification.

4 is a block diagram illustrating an ATM subscriber matching device according to the present invention, and includes a physical layer processor 22, an ATM layer processor 24, and a subscriber device controller 26 in the same manner as the ATM subscriber matcher according to the related art illustrated in FIG. 3. It is done by However, a characteristic element of the ATM subscriber matching device according to the present invention is the fact that the clock monitoring circuit 60 and the clock redundancy and recovery unit 70 are further provided.

In FIG. 4, the clock monitoring circuit 60 receives clocks Clock A and Clock B supplied to the clock distribution device 10 having the redundant structure shown in FIG. Output The clock monitoring circuit 60 may be implemented as a commercial chip. The clock monitoring circuit 60 outputs A_Fail when the state of the clock Clock A is cut, outputs B_Fail when the state of the clock Clock B is cut, and outputs A & B_Fail when all of the states of the clocks A, B are cut. . The monitoring result is notified to the subscriber station control unit 26 via the clock duplication and recovery unit 70. The subscriber station controller 26 periodically checks the monitoring result and enters the resource initialization ready state when A & B_Fail is output, that is, when the clock clocks A and B are all disconnected. When the clock Clock A or Clock B is restored, the clock redundancy and recovery unit 70 generates a resource initialization signal to initialize the resources of the physical layer processor 22 and the ATM layer processor 24 of the subscriber matching device 20. When the initialization operation for the resources of the physical layer processor 22 and the ATM layer processor 24 ends as described above, the subscriber station controller 26 communicates with the switch controller 50 to transmit data for controlling the subscriber device 30 from the switch controller 50. In response, the resources are restarted to match the state of the matching device to that before the clock cut.

FIG. 5 is a diagram illustrating a state diagram of an ATM subscriber matching device according to the present invention shown in FIG. 4.

In FIG. 5, state A indicates that clock Clock A is selected, state B indicates that clock Clock B is selected, and state C indicates that clocks Clock A and Clock B are both disconnected. Numbered arrows indicate events for state transitions. Event 1 represents an event in which Clock B transitions from active to disconnected when Clock A is active. Event 2 represents an event in which Clock A transitions from active to disconnected when Clock B is active. Event 3 represents an event in which Clock A transitions from the active state to the cut state when Clock B is cut. Event 4 represents an event in which Clock A is activated with both Clocks A and B disconnected. Event 5 represents an event in which Clock B transitions from the active state to the cut state when Clock A is cut. Event 6 represents an event in which Clock B transitions to the active state when both Clocks A and B are disconnected. Event 7 represents an event that initiates a resource after transitioning from state C to state A. Event 8 represents an event that initiates a resource after transitioning from state C to state B.

Referring back to FIG. 4, the clock redundancy and recovery unit 70 stays in the state A or state B normally and transitions to the state C when the clocks A and B are both disconnected. You are ready to initialize. After that, when the clock is recovered and transitioned to state A or state B, the clock redundancy and recovery unit 70 generates a resource initialization signal to initialize the surrounding resources, that is, the resources of the ATM layer processor 24 and the resources of the physical layer processor 22. It serves as. In response to the resource initialization signal being generated, the subscriber station control unit 26 resumes communication with the switch controller 50 and receives the subscriber device control data from the switch controller 50 and stores the data for the subscriber matching device 20 in the resource of the subscriber matching device 20. Restore the state of the subscriber matching device 20 to the state before the clock was disconnected.

As described above, the present invention has an advantage of maintaining the state of the subscriber matching device as before cutting the clock when recovering after clock cutting of the subscriber matching device. In addition, there is an advantage of maximizing the convenience of operating the exchange system by eliminating unnecessary operator registration device restart. In addition, since the subscriber control data of the switch controller and the data of the subscriber matching device can be kept the same at all times, there is an advantage of preventing malfunction of the switch.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by the equivalents of the claims.

Claims (3)

A clock recovery apparatus for a subscriber matching device having a physical layer processing unit, an ATM layer processing unit, and a subscriber unit control unit in an ATM switch, A monitoring circuit for monitoring the first clock or the second clock supplied according to the redundant structure and outputting the monitoring result. When it is monitored by the monitoring circuit that both the supply of the first clock and the second clock are disconnected, the controller prepares to initialize the resources of the physical layer processing unit and the ATM layer processing unit, and again the first clock and the second clock. And a recovery unit for initializing the resources of the physical layer processing unit and the ATM layer processing unit when one of the clocks is monitored to be recovered and supplied. A clock recovery method for a subscriber matching device including a physical layer processing unit, an ATM layer processing unit, and a subscriber station control unit in an ATM switch, (A) monitoring the first clock or the second clock supplied according to the redundant structure and outputting the monitoring result; (B) preparing to initialize the resources of the physical layer processor and the ATM layer processor when the monitoring circuit detects that the supply of the first clock and the second clock has been cut off; (C) initializing the resources of the physical layer processor and the ATM layer processor when one of the first clock and the second clock is monitored to be supplied after being restored after the step (b). Characterized in that. 3. The terminal of claim 2, wherein after the resources of the physical layer processing unit and the ATM layer processing unit are initialized, the subscriber station control unit resumes communication with the control unit of the ATM switch and receives the subscriber device control data to clock the subscriber matching unit. Further comprising restoring to a state prior to cutting.

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