KR100523373B1 - Apparatus For ONU Dechurning Processing In ATM PON System - Google Patents

Abstract

The present invention uses a specific fixed key as a tuning key at the instant of an optical distribution network (OTN) transfer of an optical line termination (OLT) in an optical network unit (ONU) of an asynchronous transfer mode (PON) passive optical network (PON) system. The present invention relates to an ONU decision processing apparatus in an ATM PON system capable of satisfying a prescribed ODN transfer time.

In the present invention, when ODN switching is performed by OLT in an ATM PON system, data defining processing is performed by using a specific fixed key as a tuning key at the time of ODN switching in the ONU. By doing so, it is possible to satisfy the ODN transfer time defined by 50 msec in the ONU, and thus it is possible to perform a normal data de-dimensioning process even during ODN transfer.

Description

Appenus for ONU Dechurning Processing In ATM PON System

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to dechurning processing in ATM (Asynchronous Transfer Mode) Passive Optical Network (PON) systems, and in particular, the Optical Distribution Network (ODN) switching of Optical Line Termination (OLT) in an Optical Network Unit (ONU). The present invention relates to an ONU decision processing apparatus in an ATM PON system capable of satisfying a specified ODN transfer time by performing a decision processing using a specific fixed key as a tuning key.

Recently, the development of transmission technology and exchange technology realizes high-speed information transmission and creates various services throughout the network environment, and as a result, the public network is advanced based on ATM (Asynchronous Transfer Mode) for B-ISDN. Is going on.

In addition, a subscriber network composed of subscriber lines between a telephone station and subscribers is based on an ATM based Asynchronous Transfer Mode-Passive Optical Network (PON) network in which a subscriber line is formed of optical fibers.

Meanwhile, the conventional ATM PON system provides voice, ISDN, leased line, xDSL, and ATM25 services through optical line termination (OLT), which is a telephone station device, and an optical network unit (ONU) installed in a subscriber area. The recommended ATM PON system structure is illustrated in FIG. 1.

Here, OLT performs the function of optical transmission to multiple ONUs, which are located in a telephone station, integrated multiplexing of DS1, DS1E signals and broadband digital hierarchy based on ATM delivered from broadband switching network, and vice versa. ODN (Optical Distribution Network) provides an optical transmission path between the OLT and each ONU and consists of an optical cable having a passive optical splitter.

In addition, each ONU performs a function of transmitting a subscriber signal extracted through the demultiplexing function from the optical signal received from the OLT to various channel units according to the service and its reverse function.

In the conventional ATM PON system as described above, data is transmitted to all ONUs at the same time since the OLT is broadcasted from the OLT to the ONU side. Therefore, the downlink data transmitted to each ONU is different for each ONU for data protection. Churning is performed on the payload portion of the ATM cell except for the header portion of the ATM cell using the Churning Key, and the received ONU uses the churning key to restore the data to its original state. Perform the function.

At this time, the training key for data encryption and restoration is generated by each ONU according to the request of the OLT and transmitted to the corresponding OLT, and between the OLT and the ONU at least once every second to prevent duplication of the training key. Perform key update.

In addition, in the conventional ATM PON system, the churning key uses a 3-byte key, and as shown in FIG. 2, a new churning key is generated in the ONU according to the OLT's churning key update request (new_key_request), thereby generating a 'new_churning_key' message. In this case, the 3-byte chening key is composed of X1 ~ X8 and P1 ~ P16 values, and each ONU has a predetermined logical operation (K1 = (X1 * P13 * P14) + (X2 * P13 * not). P14) + (X7 * not P13 * P14) + (X8 * not P13 * not P14), K2 = (X3 * P15 * P16) + (X4 * P15 * not P16) + (X5 * not P15 * P16) + (X6 * not P15 * not P16), K3 = (K1 * P9) + (K2 * not P9), K4 = (K1 * not P9) + (K2 * P9), K5 = (K1 * P10) + (K2 * not P10), K6 = (K1 * not P10) + (K2 * P10), K7 = (K1 * P11) + (K2 * not P11), K8 = (K1 * not P11) + (K2 * P11), K9 = (K1 * P12) + (K2 * not P12), K10 = (K1 * not P12) + (K2 * P12)) to obtain K1 ~ K10 values, which are encrypted by OLT. Through the operations such as the accompanying Figure 3, using the value of K and P value of the message obtained before the downlink data is sent to restore the original data.

At this time, in each ONU, if the key is properly updated, the corresponding key is stored and managed in the internal memory until the next key is updated, and the digital key is used to restore the original data from the downlink data. To do the processing.

On the other hand, the above-described message flow for the cheating key update, as shown in Figure 2, ONU receiving the 'new_key_request' message from the OLT immediately responds with a 'new_churning_key' message, when the 'new_churning_key' message to the PLOAM cell OLT transmits three times by sending 'churning_key_update' message to three PLOAM cells at intervals of 16 * T frame to prevent message loss when OLT receives three complete chening keys. At this time, if any message is received in ONU, after checking the message sequence number, new queuing key is activated (new_key active) at a certain time in consideration of the delay between each message. Valid after 16 * T frame after sending churning_key_update 'message.

In addition, in the conventional ATM PON system, the OLT locates each ONU connected to each other through ranging, so that data of each other can be transmitted without collision. In this case, the OLT can be configured to be redundant to enable ODN switching. In the case of ODN switching in OLT, TDMA transmission is performed because the lengths of the optical paths in the working state and the optical paths in the protection state are different between the OLT and the ODN. Due to the nature, data is normally transmitted through the active optical path, but data is transmitted through an optical path that is in an inactive state, that is, due to a collision, etc. It cannot be sent normally.

Therefore, the active OLT side receives the correct cheating key, but the inactive OLT side does not receive the cheating key within the required time, and when ODN switching is performed, the OLT that is currently inactive, that is, the active transitioned OLT, There is a problem in that the ONU is different from the cheating key, that is, the cheating key before being updated, and thus the data that is encrypted and transmitted by the OLT cannot be properly received by each ONU. Because it takes about 1 second, there was a problem that does not satisfy the transfer time prescribed by 50msec.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object thereof is that, when ODN switching is performed by OLT in an ATM PON system, at the instant of ODN switching in an ONU, a data fixed process is performed by using a specific fixed key as a tuning key. After that, it is possible to perform data de-processing process using the newly generated tuning key.

Another object of the present invention, by performing the data dicing process with a fixed key at the moment of ODN transfer by OLT in the ONU, it is possible to satisfy the ODN transfer time prescribed by 50msec, through which normal data dicing even during ODN transfer To allow processing to take place.

A feature of the present invention for achieving the above object is, in the ONU deduction processing apparatus for performing downlink data recovery with a predetermined key in the ATM PON system, generating a new key in response to a request for updating the key of the OLT. A storage key generation unit for storing the training key storage unit and transmitting the training key to the OLT side; A fixed key storage unit for storing a fixed key for use in data dedimentation processing at the time of ODN transfer by the OLT; A downlink synchronization monitoring unit which checks optical synchronization with respect to downlink data transmitted from the OLT and outputs a selection signal for selecting a keying key to be used in a deciding process according to whether LOS is detected; APM PIO comprising a key selector for selecting any one of the newly created tuning key or a fixed key as a tuning key for the deduction processing according to the selection signal output from the downlink synchronization monitoring unit The present invention provides an apparatus for processing OHyu deionization in an EN system.

Here, the downlink synchronization monitor outputs a selection signal for selecting a keying key to be used in the deciding process by setting or canceling a corresponding LOS detection flag according to whether or not the LOS is detected.

In addition, when the LOS is not detected as a result of checking the optical synchronization, the downlink synchronization monitoring unit outputs a tuning key selection signal for selecting a newly created tuning key as a tuning key to be used in the deciding process by canceling the LOS detection flag. And setting a LOS detection flag when detecting LOS due to ODN switching, so as to output a fixed key selection signal for selecting a fixed key as a tuning key to be used in the dicing process.

The key selector selects a fixed key stored in the fixed key storage unit as a chucking key and outputs the fixed key to the deciphering processing unit at the instant of the ODN transfer when the fixed key selection signal is inputted from the downlink synchronization monitoring. In the case of inputting, the newly generated training key stored in the training key storage unit is selected as the training key, and is output to the processing unit.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the ATM PON system according to the present invention, at the instant of ODN changeover of the OLT, a defining process of restoring downlink data received from the OLT to the original data is performed by using a predetermined fixed key as a cheating key in each ONU, and then updated. Dicing processing is performed with the tuning key, and the ONU deduction processing apparatus for this is illustrated in FIG. 4 as follows, the tuning key generation unit 41, the fixed key storage unit 42, and the downlink synchronous monitoring. A unit 43, a key selector 44, and a dicing processor 45 are provided.

When the 'new_key_request' message for requesting the renewing of the keying key is received from the OLT through the PLOAM message receiving unit 46, the keying key generation unit 41 generates a new keying key, stores the new keying key, and stores the keying key. The PLOAM message transmitter 47 transmits to the OLT side, and the fixed key storage unit 42 serves as a memory for storing a fixed key to be used in the data decontamination process at the time of ODN changeover by the OLT.

The downlink synchronization monitor 43 checks optical synchronization with respect to downlink data transmitted from the OLT and selects a selection signal SEL for selecting a tuning key to be used in the deciding process according to whether the LOS (Loss Of Signal) is detected. At this time, the corresponding LOS detection flag (Flag) is set or released according to whether or not LOS is detected, and the LOS detection flag is set during instantaneous LOS detection due to ODN switching, so that it is fixed by the tuning key to be used in the dicing process. A fixed key selection signal for selecting a key is output to the key selection section 44. If the LOS is not detected as a series of cheating key update procedures are completed after the ODN changeover, the corresponding LOS detection flag is canceled so that the newly generated cheating key can be selected as the cheating key to be used in the dicing process. The key select signal is output to the key select section 44.

The key selector 44 selects and outputs one of the newly generated tuning keys or the fixed key as the tuning key CK for the deduction processing according to the selection signal output from the downlink synchronization monitor. At the moment of switching, the fixed key is selected as a chucking key as the fixed key selection signal is input from the downlink synchronization monitor, and then the newly generated chucking key is selected as the chucking key for the deduction processing as the chucking key selection signal is input. To print.

The dicing processor 45 performs the dicing process for restoring the original data by using the tuning key outputted from the key selector 44 for the downlink data transmitted from the OLT. At this time, the decanting processor 45 performs the decanting process by performing the operation shown in FIG.

Meanwhile, in the above-described ONU dicing processing apparatus, the configuration related to the generation and selection of the keying key may be configured as illustrated in FIG. 5. The fixed key storage unit 42 performs the dicing processing at the instant of ODN transfer. The fixed key to be used is stored. At this time, the training key generation unit 41 generates a new training key and stores the newly created training key in the internal or separately configured training key storage unit.

The downlink synchronization monitor 43 checks the optical synchronization with respect to the downlink data transmitted from the OLT. If the LOS is not detected, the downlink synchronization monitor 43 cancels the setting key selection signal SEL (0) by canceling the LOS detection flag. If LOS is detected due to ODN switching, the fixed key selection signal SEL 1 is output to the key selector 44 by resetting the corresponding LOS detection flag. If the LOS is not detected after the ODN switchover is completed and the LOS is not detected, the corresponding LOS detection flag is canceled, and the chucking key select signal (SEL; 0) is output to the key selector 44 again. do.

At this time, the key selector 44 generates a newly generated data stored in the churning key storage unit according to the key selection signal from the downlink synchronization monitor 43, that is, when the keying key selection signal SEL: 0 is input. When the key is selected as the key for dicing, the key is output to the dicing processor 45. When the fixed key selection signal SEL 1 is input, the key stored in the fixed key storage 42 is fixed. The key is selected as the tuning key for the deduction process and is output to the deduction process unit 45.

Referring to the ONU decision processing operation in the ATM POM system according to the present invention having the configuration as described above is as follows.

First, in the OLT of the ATM PON system, data is transmitted to each ONU side in the form of an ATM cell. At this time, the ATM cell data transmitted by the OLT is broadcast to all ONUs, so that the ONUs and the corresponding ONUs for data protection are transmitted to a specific ONU. The payload portion of the ATM cell received from the OLT is transmitted from the OLT using its own chening key. The de-dimensioning process is performed.

In addition, the OLT and each ONU update the tuning key at least once every second to prevent duplication of the corresponding training key.In this case, the ONU generates a new training key and transmits it to the OLT side at the request of the OLT. Meanwhile, a dicing process is performed to restore the downlink ATM cell data transmitted from the OLT to the original data using the tuning key.

That is, when the PLOAM message receiving unit 46 of the ONU receives the 'new_key_request' message requesting the keying key update, the PLOAM message receiving unit 46 transmits the message to the channeling key generating unit 41, and the channeling key generating unit 41 performs the cheating from the OLT. When a 'new_key_request' message requesting a key update is received, a new training key is generated and stored in the training key storage unit, and the training key is transmitted to the OLT side through the PLOAM message transmitter 47.

At this time, the downlink synchronization unit 43 checks the optical synchronization of the downlink data transmitted from the OLT to determine whether a LOS (Loss Of Signal) is detected. In the normal state in which ODN switching is not performed, the LOS is detected. Since the LOS detection flag is not set, the channeling key selection signal SEL 1 is outputted to the key selector 44.

In addition, the key selector 44 inputs the tuning key selection signal SEL 1 from the downlink synchronization monitor 43 to adjust the key stored in the tuning key storage unit. It selects as and outputs to the deduction processing unit 45, the deduction processing unit 45 is a downlink ATM cell transmitted from the OLT by using the tuning key output from the key selection unit 44, that is, the newly generated tuning key The dicing process for restoring the data to the original data is performed.

As described above, when ODN switching is performed in OLT due to a failure or the like during the downlink data dicing process by using the newly created chening key in ONU, the OLT which is currently active is transitioned to inactive state. The OLT in the inactive state transitions to the active state to perform continuous ATM cell data transmission processing, which results in a momentless dark section due to ODN switching.

Therefore, the down-synchronization monitoring unit 43 of the ONU detects LOS as a dark section occurs due to a corresponding ODN switching while checking the optical synchronization for downlink data transmitted from the OLT. Accordingly, the LOS detection flag is set accordingly. The fixed key selection signal (SEL; 0) is outputted to the key selection unit 44.

Accordingly, the key selector 44 receives a key for dicing the key stored in the fixed key storage 42 as the fixed key select signal SEL (0) is input from the downlink synchronization monitor 43. Selected as (CK) and output to the dicing processing unit 45, the dicing processing unit 45 in advance for use in the dicing process at the moment of ODN transfer, that is, the adjustment key output from the key selection unit 44, The fixed key is used to perform the dicing process to restore the downlink ATM cell data transmitted from the OLT to the original data. That is, in the present invention, the ONU checks the optical synchronization with respect to the downlink data to check whether the LOS is detected, and restores the downlink ATM cell data of the OLT to the original data by using the fixed key as the cheating key during instantaneous LOS detection due to ODN switching. As a result, the transfer time specified by 50 msec can be satisfied.

Thereafter, after the ODN switching is performed, the OLT synchronizes the ONU and the churning key with each other through a series of switching of the keying updates, thereby preventing the LOS from being detected by the ONU's downlink synchronization unit 43. Accordingly, the LOS detection flag is reset again, and the channeling key selection signal SEL 1 is output to the key selection unit 44.

In addition, as the key selection signal SEL 1 is inputted again from the downlink synchronization monitor 43, the key selector 44 performs the adjustment key CK for dicing the key stored in the keying storage unit. ) To be output to the dicing processor 45, and the dicing processor 45 transmits the downlink ATM transmitted from the OLT using the newly generated cheating key, that is, the newly generated cheating key. The dicing process for restoring the cell data to the original data is performed. That is, in the present invention, the ONU checks the optical synchronization for the downlink data to check whether the LOS is detected. As a result, the ONU performs the dicing process on the downlink ATM cell data of the OLT by using the fixed key as the cheating key at the time of ODN transfer of the OLT. The transfer time defined by 50msec can be satisfied, and after that, the dicing process on the downlink ATM cell data of the OLT is performed by using the newly generated tuning key to protect the downlink data broadcast to each ONU by the OLT. Done.

In addition, the embodiments according to the present invention are not limited to the above-described embodiments, and various alternatives, modifications, and changes can be made within the scope apparent to those skilled in the art.

As described above, in the present invention, when ODN switching is performed by OLT in the ATM PON system, data defining processing is performed by using a specific fixed key as a chucking key at the time of ODN switching in the ONU, and then data is generated by a newly generated chucking key. By performing the dicing process, it is possible to satisfy the ODN transfer time defined by 50 msec in the ONU, and thus it is possible to perform the normal data dicing process even during ODN transfer.

1 is a diagram showing the structure of a typical ATM PON system.

2 is a diagram illustrating a message transmission / reception procedure for updating a cheating key in a conventional ATM PON system.

3 is a diagram illustrating a cheating processing circuit for explaining an operation of encrypting data through a logical operation using a cheating key in a conventional OLT.

Fig. 4 is a block diagram showing an ONU decision processing apparatus in an ATM PON system according to the present invention.

FIG. 5 is a diagram illustrating a configuration relating to generation and selection of a keying key in the ONU dicing processing apparatus according to the present invention; FIG.

Explanation of symbols on the main parts of the drawings

41: churning key generation unit 42: fixed key storage unit

43: down synchronization monitor 44: key selector

45: dicing processor 46: PLOAM message receiving unit

47: PLOAM message transmitter

Claims (4)

An ONU dicing processing apparatus for performing downlink data recovery with a predetermined tuning key in an ATM PON system, A training key generation unit for generating a new training key in response to a request for updating a training key of an OLT, storing the new training key, and transmitting the training key to the OLT; A fixed key storage unit for storing a fixed key for use in data dedimentation processing at the time of ODN transfer by the OLT; A downlink synchronization monitoring unit which checks optical synchronization with respect to downlink data transmitted from the OLT and outputs a selection signal for selecting a keying key to be used in a deciding process according to whether LOS is detected; And a key selector configured to select any one of the newly generated tuning key or the fixed key as a tuning key for the deduction processing according to the selection signal output from the downlink synchronization monitor and output the selected key to the dedition processing unit. OYU de-essence processing apparatus in the AMT PME system. The method of claim 1, The downlink synchronization monitoring unit outputs a selection signal for selecting a tuning key to be used in the dicing process by setting or canceling a corresponding LOS detection flag according to whether the LOS is detected or not. Churning processing device. The method of claim 2, The downlink synchronization monitoring unit outputs a tuning key selection signal for selecting a newly generated tuning key as a tuning key to be used in the deciding process by canceling the LOS detection flag when the LOS is not detected as a result of the optical synchronization. When the LOS is detected due to ODN switching, the Oenyu Dicing processing apparatus in the ATM PIOEN system is configured to output a fixed key selection signal for selecting a fixed key as a tuning key to be used in the dicing process by setting the LOS detection flag. . The method of claim 1, The key selector selects a fixed key stored in the fixed key storage unit as a chucking key and outputs the fixed key to a deciphering processing unit at an instant of the ODN transfer when the fixed key selection signal is inputted from the downlink synchronization monitoring. In the case of the Oenyu Dicing processing apparatus of the AMT POE system, characterized in that the newly generated cheonning key stored in the cheoning key storage unit is selected as the cheoning key and output to the deduction processing unit.