KR100611902B1 - Apparatus For OLT Churning Processing In ATM PON System - Google Patents

Abstract

According to the present invention, it is possible to satisfy a specified switching time by using a specific common key as a chucking key at the moment of optical distribution network (ODN) transfer in OLT (Optical Line Termination) of an Asynchronous Transfer Mode (ATM) Passive Optical Network (PON) system. An OLT cheating processing apparatus in an ATM PON system.

In the present invention, when ODN switching is performed in an OLT of an ATM PON system, data encryption is performed using a specific common key as a cheating key at the moment of switching, and afterwards, data encryption is performed with an updated chewing key, thereby defining 50 msec. The transfer time can be satisfied, so that normal data transfer processing can be performed even during ODN changeover.

Description

Apparatus For OLT Churning Processing In ATM PON System

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.

4 is a block diagram illustrating an OLT cheating processing apparatus in an ATM PON system according to the present invention;

FIG. 5 is a diagram showing a detailed circuit of a key selection unit in FIG. 4; FIG.

FIG. 6 is a diagram showing a detailed circuit of a key output unit in FIG. 4; FIG.

Explanation of symbols on the main parts of the drawings

40: churning processing unit 50: key selection unit

60: key output unit 61: the cheating key storage unit

62: common key storage unit 63: output unit

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to the processing for encryption in an Asynchronous Transfer Mode (ATM) Passive Optical Network (PON) system, and more particularly, to a particular common key at the instant of optical distribution network (ODN) switching in an optical line termination (OLT). The present invention relates to an OLT cheating processing apparatus in an ATM PON system capable of satisfying a prescribed transfer time.

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 by using the Churning Key, and the received ONU decrypts the data using its own Churning Key. Perform the function.

At this time, the chening key for encryption is generated in each ONU according to the OLT request and transmitted to the corresponding OLT, and the cheating key is updated between the OLT and the ONU at least once every second to prevent duplication of the cheating key. Perform.

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. It is transmitted to OLT through 3 bytes of chening key consisting of X1 ~ X8, P1 ~ P16 value, and 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) and K10 = (K1 * not P12) + (K2 * P12)) to find the K1 ~ K10 values. The data is encrypted through the operation as shown in FIG. 3 attached thereto, and then downlink data is transmitted to each ONU.

At this time, the message flow for updating the cheating key described above, upon receiving the 'new_key_request' message from the OLT, immediately responds with the 'new_churning_key' message, where the 'new_churning_key' message is sent 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 to solve the above-mentioned problems. The object of the present invention is to encrypt data by selecting a specific common key commonly used in each ONU as a switching key when performing ODN switching in an OLT of an ATM PON system. To be able to do this.                         

In addition, the present invention is to perform the data encryption with a common key at the time of ODN transfer in the OLT, it is possible to satisfy the transfer time prescribed by 50msec during ODN transfer.

A feature of the present invention for achieving the above object is, in the OLT churning processing apparatus for transmitting data to the ONU by performing a data encryption with a predetermined key in the ATM PON system, a new message during the output of the keying key selection signal A key selector for outputting a common key selection signal at the moment of switching when ODN switching is normally performed when the switch is not normally received; According to a key selection signal output from the key selection unit, one of the common key commonly applied to each ONU or a new tuning key periodically updated by each ONU is selected and output as the tuning key for data encryption. It is to provide an OTC cheating processing apparatus in an AMT POE system including a key output unit.

Here, the key selector receives an active display signal indicating whether the OLT is active or inactive and a reception state signal indicating a new chewing message reception state as an input of the AND gate, and outputs a predetermined key selection signal for selecting the chewing key. Characterized in that.

When the OLT operates normally, the key selector outputs a chucking key selection signal to select a new chucking key periodically updated by each ONU as a chucking key, and a new chucking message is not normally received at the time of ODN switching. Accordingly, the common key selection signal may be output to select the common key as the tuning key.

In addition, the key selector, if the position of each ONU is correctly determined by the distance measurement after the ODN switching is performed, if a new churning message is normally received, data encryption of a new churning key periodically updated by each ONU And outputs a tuning key selection signal to select with a tuning key for.

On the other hand, the key output unit, a common key storage unit for storing a common key commonly applied to each ONU, a cheating key storage unit for storing a new keying key periodically updated by each ONU, and a key selection unit And an output unit for selecting one of the common key or the new tuning key stored in each storage unit as a tuning key for data encryption, and outputting the key according to the key selection signal output from the storage unit.

When the common key selection signal is input from the key selection unit, the key output unit selects and outputs a common key stored in the common key storage unit as a tuning key for data encryption, and then inputs the tuning key selection signal. The new training key stored in the training key storage unit may be selected as a training key for data encryption and output.

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, the OLT is encrypted using a common key that can be commonly used by all ONUs at the instant of ODN changeover as a cheating key, and then encrypted with an updated cheating key to transmit data. As shown in FIG. 4, the processing apparatus includes a key selection unit 50, a key output unit 60, and a chewing processing unit 40.

The key selector 50 receives an active display signal WP indicating whether the OLT is active or inactive, and a reception state signal NACK indicating a reception state of a new churning message new_churning_key as an input of the AND gate. A selection signal SEL for selecting the tuning key is output, and as shown in FIG. 5, an active display signal WP and each reception state signal NACK # 0 to NACK #n are inputted to the AND gate. By performing the AND operation, the select signal (SEL # 0 to SEL #n) for selecting the keying key is output, and the active display signal WP is '1' when the OLT is active, and each received state signal. NACK # 0 to NACK #n have '0' as logical values when a new churning message (new_churning_key) is received.

The key output unit 60 stores a common key and a new keying key received from each ONU, and selects one of the new keying key or the common key according to the selection signal output from the key selecting unit 50 to set the keying key. (CK), which is a storage unit 61 and 62 for storing new tuning keys NK # 0 to NK # n and a common key, respectively, as shown in FIG. According to the selection signal output from 50, one of the new keying keys NK # 0 to NK # n and the common key stored in each of the storage units 61 and 62 is selected, and the keying key for data encryption ( And an output unit 63 for outputting to CK # 0 to CK #n. As a result, at the moment of ODN switching, a common key is selected and output as a cheating key, and a new chening key periodically updated by each ONU is selected and output as a cheating key.

The channeling unit 40 encrypts the ATM cell data to be transmitted to each ONU with a channeling key output from the key output unit 60 and outputs the encrypted key. At this time, the channeling unit 40 performs the operation shown in FIG.

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

First, in the ATM PON system, the active side OLT transmits data in the form of ATM cell. At this time, the ATM cell data transmitted from the active side OLT is broadcast to all ONUs. And the payload portion of the ATM cell is encrypted and transmitted using the cheating key, which is a predetermined encryption key. The ONU decodes the payload portion of the ATM cell using its own chening key to receive data.

In addition, the OLT and each ONU update the tuning key at least once every second to prevent duplication of the corresponding training key, and the OLT encrypts the ATM cell data using the updated training key and transmits it to the ONU side. do.

In other words, the OLT stores and manages a new key that is periodically updated by each ONU in the keying unit 61 of the key output unit 60, and the key output unit 60 manages the key selection unit 50. According to the selection signals SEL # 0 to SEL #n output from the controller, one of the new tuning key or the common key is selected to select the tuning key CK # 0 to CK #n for data encryption, and the tuning processor 40 Will be printed.

Then, the channeling unit 40 encrypts ATM cell data using the channeling keys CK # 0 to CK # n output from the key output unit 60 and transmits the ATM cell data to the ONU side through the active side ODN.

For example, in the normal state in which ODN switching is not performed, the key selection unit 50 of the active side OLT is currently in the state where the OLT is active and a new churning message (new_churning_key) is normally received. ) '1' and receiving status signal (NACK # 0 ~ NACK #n) '0' are input, and the selection signal (SEL # 0 ~ SEL #n) '0' is obtained as the result of AND operation of the previous two signals. As a result, the key output unit 60 is stored in each churning key storage unit 61 as the selection signals SEL # 0 to SEL #n '0' are input from the key selection unit 50. Select the key as a cheating key and output it to the cheating processing unit 40. The chening processing unit 40 outputs the cheating keys (CK # 0 to CK #n) output from the key output unit 60, that is, by each ONU. The ATM cell data is encrypted with a new quenching key (NK # 0 to NK #n) which is updated periodically and transmitted to each ONU side through the active ODN. It becomes.

As described above, when ODN switching is performed for reasons such as a failure while ATM ATM data is encrypted and transmitted to each ONU side by using a predetermined cheating key, the currently active OLT transitions to an inactive state and becomes inactive. The OLT in the state transitions to the active state and performs continuous ATM cell data transmission processing. In this case, the key selector 50 of the active transitioned OLT performs ODN switching as the current OLT transitions to the active state. At the same time, the active display signal WP is received. However, in the case of a new churning message (new_churning_key), it is not normally received due to a collision or the like at the moment of ODN switching, and thus receives a reception status signal (NACK # 0 to NACK #n) '1'.

Accordingly, the key selector 50 selects the signal SEL as a result of the AND operation of the two previous signals, that is, the active display signal WP '1' and the reception state signals NACK # 0 to NACK #n '1'. # 0 ~ SEL #n) It outputs '1'.

At this time, the key output unit 60 inputs the key stored in the common key storage unit 62 as the selection signals SEL # 0 to SEL #n '1' are input from the key selection unit 50. It selects CK # 0 to CK #n and outputs it to the cheating processing unit 40. Accordingly, the chening processing unit 40 outputs the cheating key (CK # 0 to CK #n) output from the key output unit 60. That is, ATM cell data is encrypted with a common key that can be used by each ONU and transmitted to each ONU side. That is, in the present invention, the OLT encrypts ATM cell data using a common key as a cheating key and transmits it to each ONU at the instant of ODN transfer, thereby satisfying a transfer time defined by 50 msec.

In addition, after ODN switching is performed, the OLT accurately determines the location of each ONU through ranging, and thus receives a new churning key updated by each ONU, that is, a new churning message (new_churning_key). Accordingly, the key output unit 60 stores the new churning key updated by each ONU in its own churning key storage 61, and at this time, a new churning message new_churning_key is normally received to receive a reception state signal. (NACK # 0 to NACK #n) transitions from '1' to '0'.

Accordingly, the key selector 50 performs an AND operation on the active display signal WP '1' and the reception status signals NACK # 0 to NACK #n '0', and selects the signals SEL # 0 to SEL #n. ) '0' is outputted to the key output unit 60.

Accordingly, the key output unit 60 stores the key NK # 0 stored in the channeling key storage unit 61 as the selection signals SEL # 0 to SEL # n '0' are input from the key selection unit 50. ~ NK #n is selected as the cheating keys CK # 0 to CK #n, and is output to the cheating processing unit 40. Accordingly, the chening processing unit 40 outputs the cheating key output from the key output unit 60. (CK # 0 to CK #n), that is, ATM cell data is encrypted with the tuning keys NK # 0 to NK #n updated by each ONU and transmitted to each ONU side. That is, in the present invention, the OLT encrypts the ATM cell data using the common key as the cheating key at the moment of ODN transfer, and transmits it to each ONU side to satisfy the transfer time defined by 50 msec, and then by each ONU. By encrypting and transmitting ATM cell data using the updated cheating key, downlink data broadcast to each ONU is protected.

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, when the ODN switching is performed in the OLT of the ATM PON system, the data encryption is performed by using a specific common key as the cheating key at the moment of switching, and then the data is encrypted with the updated chewing key. The transfer time specified by 50 msec can be satisfied, and thus, normal data transfer processing can be performed even during ODN transfer.

Claims (6)

An OLT cheating processing apparatus for performing data encryption with a predetermined cheating key in an ATM PON system and transmitting the data to the ONU side, A key selection unit for outputting a common key selection signal at the moment of switching when ODN switching is performed in which a new tuning message is not normally received while outputting the tuning key selection signal; According to a key selection signal output from the key selection unit, one of the common key commonly applied to each ONU or a new tuning key periodically updated by each ONU is selected and output as the tuning key for data encryption. The OLT cheoning processing apparatus of the ATMP system which comprises the key output unit. The method of claim 1, The key selector is configured to receive an active display signal indicating whether the OLT is active or inactive and a reception state signal indicating a new chewing message reception state as an input of the AND gate to output a predetermined key selection signal for selection of the cheating key. OLT chewing processing apparatus in the AMT PIOEN system characterized in that. The method of claim 2, The key selector outputs a chucking key selection signal to select a new chucking key periodically updated by each ONU when the OLT operates normally, and a new chucking message is not normally received at the time of ODN switching. And a common key selection signal for selecting a key as a cheating key. The method of claim 1 or 3, The key selector is configured to perform data encryption on a new churning key that is periodically updated by each ONU when a new churning message is normally received as the location of each ONU is accurately determined through distance measurement after ODN switching is performed. An OTL tuning processing apparatus in an ATM PIOEN system, characterized in that for outputting a selection key selection signal to select with a tuning key. The method of claim 1, The key output unit may include a common key storage unit for storing a common key commonly applied to each ONU, a tuning key storage unit for storing a new keying key periodically updated by each ONU, and an output from the key selection unit. In response to the key selection signal, the ATM PIO system comprising an output unit for selecting and outputting one of the common key stored in each of the storage unit or a new keying key as a tuning key for data encryption OLT Chewing Processing Unit. The method of claim 5, When the common key selection signal is input from the key selection unit, the key output unit selects and outputs the common key stored in the common key storage unit as a cheating key for data encryption, and when the churning key selection signal is input, the churning. The OLT chewing processing apparatus of the AMT POE system, characterized by selecting and outputting a new cheating key stored in the key storage unit as a cheating key for data encryption.

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