Abstract: A method for managing a service bandwidth by a customer port and an EPON system using the same are provided. In order to manage the service bandwidth by a customer, ONU and ONT allocate a service class according to a combination of information about a customer that receives a service, and a service type and a service priority of a service provided to a customer, allocate a bandwidth according to each service class and control a uplink bandwidth or a downlink bandwidth according to a service class. Also, a system manger collects information about a service provider, a service provided from a service provider, a customer that receives a service, and information for classifying a service. After collecting, the system manager provides the collected information to the ONU and the OLT.

Abstract: An authentication method for link protection between an OLT and an ONU newly connected thereto in an EPON, which is implemented in a data link layer to which cryptography is applied. First, an authentication key is distributed to both the OLT and an ONU. The OLT (or ONU) generates first and second random values, generates an authentication request frame containing the random values, and transmits it to the ONU (or OLT). The ONU generates a first hash value according to a hash function using the random values contained in the request frame, and transmits an authentication response frame containing the first hash value to the OLT. The OLT compares the first hash value with a second hash value calculated by it according to the has function using the two random values and an authentication key distributed to it, and transmits an authentication result frame to the ONU.

Abstract: A method for controlling a security channel for reducing system load by extending the use period of a security association key is provided. In this method, an upper bit initial value of an initialization vector of an encryption algorithm and a using range thereof are shared between a transmitting side and a receiving side when a security channel is created. Then, a secure association is created between a transmitting side and a receiving side by setting an association number, a next packet number which is a lower bit value of an initialization vector, and a secure association key. Afterward, a packet number is modified whenever a frame is transmitted until all of packet numbers are used. When all packet numbers are used, the upper bit value of the initialization vector changes.

Abstract: The invention relates to an EPON bridge apparatus and a forwarding method thereof. In a case of receiving a frame from the network port or the PON port, the apparatus associates the port having the received frame inputted with a source MAC address of the received frame to learn the information in an FDB table, which manages port information for the learned MAC address. Then the apparatus refers to the FDB table to remove an LLID from upstream frame, and then forwards the upstream frame to the network port, while attaching an LLID corresponding to a destination MAC address to the downstream frame to transmit to the PON port. Bridging between ONUs is possible with flooding capability using an anti-LLID. VLAN-LLID translation mode is provided with support for VLAN tag addition/removal at the ONU side. A multicast pruning function is provided for the downstream.

Abstract: An apparatus and method for allocating a bandwidth for up-stream data transmission to a plurality of Optical Network Units (ONUs) in an Ethernet Passive Optical Access Network (EPON) in which the ONUs are connected to a single Optical Line Terminal (OLT) are disclosed.

Abstract: A transimpedance amplifier for a burst mode optical communication converts a burst current signal into differential output voltage signals. Using a multi-level digital AGC mechanism, the transimpedance amplifier is rapidly adapted to a burst signal whose amplitude varies in a wide range. By using an adaptive level detection method, a multi-level digital AGC can be implemented without using ADC. In addition, because the transimpedance amplifier uses a selective reset generation scheme that performs a reset operation for itself after a high power burst, a burst mode operation can be performed without external reset signals. Accordingly, the transimpedance amplifier can be integrated with an optical detector within a TO-can. Furthermore, the transimpedance amplifier can have the burst mode capability and the best sensitivity.

Abstract: A passive optical network system includes: a plurality of optical signal splitter receiving optical signals from a plurality of optical network units (ONUs) to provide a plurality of upstream optical signals having different wavelengths; a hybrid optical filter multiplexing the plurality of upstream optical signals in a wavelength division multiplexing (WDM) scheme; and an optical line terminal (OLT) receiving the multiplexed upstream optical signals in a time division multiplexing (TDM) scheme. Therefore, the network system can be easily expanded when the number of subscribers increases, and the optical loss can be minimized.

Abstract: The present invention provides a device and method for allocating a bandwidth to a plurality of optical network units (ONUs) for transmitting an uplink frame in the EPON. The bandwidth allocation device includes a plurality of optical network units and an optical line terminal (OLT). The optical network units classify uplink data to be transmitted to an optical line terminal according to a predetermined priority, and transmit the classified uplink data by receiving an allocated bandwidth according to each class from the optical line terminal. The optical line terminal preferentially distributes a predetermined bandwidth for transmitting uplink frames of a highest priority class to the optical network units and then dynamically distributes a remained bandwidth form transmitting the uplink frames for remained classes.

Abstract: A method and device for controlling security of a communication channel between an OLT and an ONU in a secure channel control system of EPON formed of the OLT and the ONU having a cryptographic module, a key management module and a transmitter/receiver for transmitting/receiving frames, the method comprising the steps of: a) distributing a key between the OLT and the ONU; b) transferring the distributed key to the encryption modules of the OLT and ONU; c) activating a corresponding encryption module using the distributed key at one of the OLT and the ONU which starts a security function activation; d) transmitting an encryption module information message including activation state information of the corresponding encryption module from the side (transmitting side) having the activated encryption module to an opponent side (receiving side); and e) activating an encryption module by checking activation state information of the encryption module at the receiving side.

Abstract: The present invention provides a method for detecting a security module for link protection in an EPON, wherein an OLT and an ONU in the EPON can check whether or not an encryption module is present in each other and check the configuration of each other in order to avoid loss of a message when the message is encrypted for link protection between the OLT and the ONU in the EPON.

Abstract: A key management method for encrypting a frame in an Ethernet passive optical network (EPON) is provided. In the method, secure parameters including secure keys and their association numbers which are used in the present or will be used in the next by each secure channel are managed by composing a key information table. Then, it determines whether an association number of a received encryption frame is valid or not with reference to the key information table if the encryption frame of which association number has been changed is received. A secure key changes if the association number is determined to be valid, and the secure key does not change if the association number is not valid.

Abstract: Provided is an optical filtering apparatus which is applied to a Time Division Multiplexing Passive Optical Network (TDM-PON) based on a wavelength division multiplexing (WDM) method. The optical filtering apparatus includes: an optical signal distributing unit dividing an optical signal received from an optical line terminal into at least one optical signal with uniform output intensity, and distributing the at least one optical signal into at least one optical network unit; and a multiplexing unit combining a plurality of optical signals having different wavelengths received from the at least one optical network unit using a wavelength division multiplexing (WDM) method, and outputting the combined optical signal to the optical line terminal. Therefore, by using the optical filtering apparatus, it is possible to connect a large number of subscribers to an Optical Line Terminal (OLT) on a network such as Fiber To The Home (FTTH), thereby increasing efficiency in costs.

Abstract: Disclosed is a device and method for optical supervisory channel framing in an optical transport network system including at least one of an optical transmission section, an optical multiplex section, and an optical channel section. A maintenance signal is generated according to a first LOS (Loss OF Signal) signal generated from at least one of the optical transmission section, the optical multiplex section, and the optical channel section. The maintenance signal and a frame-related channel such as a message communication channel are multiplexed to generate an optical supervisory channel frame. The optical supervisory channel frame is output to another device including a repeater and a terminal system through a single supervisory channel.

Abstract: The invention relates to an EPON bridge apparatus and a forwarding method thereof. In case of receiving frame from the network port or the PON port, the apparatus associates the port having the received frame inputted with source MAC address of the received frame to learn the information in an FDB table which manages port information for the learned MAC address. Then the apparatus refers to the FDB table to remove LLID from upstream frame, and then forwards the upstream frame to the network port, while attaching LLID corresponding to destination MAC address to downstream frame to transmit to the PON port. Bridging between ONUs are possible with flooding capability using anti-LLID. It provides VLAN-LLID translation mode with support for VLAN tag addition/removal at the ONU side. It also provides multicast pruning function for the downstream.

Abstract: A method and apparatus for duplex protection switching by using a single splitter in a passive optical network (PON) are provided. The apparatus for duplex protection switching in a PON, in which a single optical line termination (OLT) and many optical network terminations (ONTs) are connected together in a multiple-access manner, includes: a 2:2 splitter connected to two PON line terminations (LTs) in the OLT; and two N:1 splitters which are connected to the 2:2 splitter, and each of which is connected to two PON LTs in the ONT. According to the method and apparatus, an economical effect can be provided in which two links, an operational link and a protection link, in the PON can provide a partial duplex function at a lower cost. Also, a protection switching time can be reduced by simplifying a restoration process so that when an error is detected, an operational state is returned by protection switching.

Abstract: The method for operating an optical transponder, which performs maintenance of a signal in the optical transponder having a digital wrapper in an optical transmission system including multiple layers, includes (a) calling a processor for processing an interrupt when the interrupt is generated from the digital wrapper according to monitoring of a received signal; (b) the called processor detecting what defect is generated in the received signal and detecting whether or not the received signal requires maintenance; (c) performing defect processing in the case that a defect is detected at (b) or is cancelled; and (d) controlling the digital wrapper according to the defect and maintenance processing result.

Abstract: A system and a method for providing a secured transmission through an authenticated encryption for each ONU in downlink transmission of an OLT in GPON are provided. The GPON system includes an OLT for generating a GTC downlink frame by receiving data from an external service provider and ONUs for receiving the GTC downlink frame from the OLT and processing the received GTC downlink frame. The OLT performs the authenticated encryption for the generated GTC downlink frame according to the ONU by including an authentication generator and the ONU determines whether the GTC downlink frame is allowed to be processed or not by checking the authentication of the received GTC downlink frame through an authentication checker.

Abstract: An optical channel power equalizer for equalizing the per-channel power levels of a multi-channel optical signal is provided. The channel power equalizer includes an optical spectrum measurement unit that extracts a portion of the amplified optical signal and measures the per-channel power levels of the extracted optical signal; a controller that compares the measured power levels with a predetermined reference value, and determines to output the degrees of attenuation per channel based on differences between the measured per-channel power levels and the reference value; and a per-channel optical attenuation unit that attenuates the per-channel power levels of a plurality of input optical signals based on the degrees of attenuation and outputs the attenuated optical signals as the plurality of channels.

Abstract: A method and apparatus for receiving burst data in an OLT of an EPON are provided. The method includes the steps of: a) receiving burst data from the plurality of ONUs; b) generating a multipoint control protocol (MPCP) LOS signal for reducing a synch time of the burst data; c) reducing the synch time in response to generation of the MPCP LOS signal; and d) recovering the received burst data by performing a code-group sort in a period where the MPCP LOS signal is not generated.

Abstract: An apparatus and method for managing traffic using a VID in EPON are provided. The apparatus includes a MAC lookup table, a service classification policy table, a service control policy table, a MAC lookup unit, a first and second classification module, a VID learning unit and a first and second service control module. The apparatus classifies all packets of up/downlink transmission flow using a VID into a VID unit, through the first and second classification modules and manages traffic thereof according to the parameters thereof through the first and second service control modules. Accordingly, a large amount of traffic for numerous subscribers and services thereof, which was cannot be processed by the limitation on embodying a typical switch or router, can be processed according to the present invention.