Abstract: A method may include: (i) in response to clearing of a fault on a working path of a protection switching group to which a first network element is interfaced: (a) transitioning, by the first network element, its state to a first state in which a protection path of the protection switching group is active; and (b) initiating, by the first network element, a wait to restore timer, the wait to restore timer having a duration such that upon expiration of the timer, the first network element is configured to switch the working path to active; and (ii) in response to receiving a message from a second network element interfaced to the protection switching group indicating that a failure has occurred on the working path: (a) maintaining, by the first network element, its state in the first state; and (b) continuing, by the first network element, the wait to restore timer.

Abstract: Schemes are provided for starting up optical transmission links where, after a link interruption, endpoints switch into a startup mode original detection state, and a query-transmit pulse goes out at both end points at given time intervals. In a “TRANSMITTED” handshake mode, in a loop to be passed through n times, and at least once, after the transmission of a transmit pulse, it is detected whether a received pulse is received within a given time span. If no received pulse is received, then the mode is ended and the system is returned to the original detection state. If a received pulse is received, it is answered with another transmit pulse. After the last transmit pulse, if another received pulse occurs within a given time span, the link is activated. If not, the “TRANSMITTED” handshake mode ends and the system enters the original detection state.

Abstract: A method and system for service protection based on the Dual Node Interconnection (DNI) protection structure in the transport network are provided. When creating a DNI protection group, a plurality of services are configured in one direction, wherein one is a working service, and the others are protection services; the multiple services have the same add node and drop node, but not exactly the same passed interconnection nodes; on each interconnection node of the add ring, two services in the DNI protection group through the local node to the drop ring are adapted as two services in a 1+1 protection group; on the drop node, services in the DNI protection group are adapted as two services in a 1+1 protection group transmitted from two directions of the drop ring; when a fault occurs, said interconnection node and drop node execute switching according to the 1+1 protection protocol.

Abstract: The invention discloses a system, a method and an apparatus for optical network protection. The system includes: an output control apparatus for obtaining protection mode information configured by a system and controlling an input signal to be output from a set line corresponding to said protection mode information; and a detection control apparatus for detecting powers of signals transmitted on an active line and on a standby line, if it is determined that said active line is abnormal and said standby line is normal according to detection results, then controlling said input signal to be output from a protection line corresponding to said protection mode information; if it is determined that said active line is normal, or that said active line and said standby line are abnormal according to the detection result, then controlling said input signal to be output from a set line corresponding to the protection mode information.

Abstract: The design of optical telecommunication networks is such that there is provision of end-to-end path restoration to specified demands under up to two links or nodes failures. Restoration routes are provided on Path Protecting Preconfigured Cycles (PP-PCs), where each demand is assigned one or two restoration routes and restoration wavelengths on a segment of one cycle. Splitting of demand across multiple restoration routes is not allowed. All restoration routes and restoration wavelengths are predetermined where multiple demands may share restoration wavelengths without resorting to intermediate switching or wavelength conversions along restoration routes. First, numerous candidate PP-PCs are generated. Assignment of demands with common failure scenarios are allowed, under certain conditions, to the same PP-PC. Next, a set of PP-PCs is selected from among the candidates, while minimizing total reserved restoration wavelengths cost and ensuring that all demands are protected as required.

Abstract: An optical transmission apparatus connected to an optical ring network stores identification information of an optical transmission apparatus as a communication partner predetermined on a communication path. Each optical transmission apparatus includes self identification information in header information of an optical signal having a working wavelength used in normal operation, and transmits the optical signal to one of the two optical ring networks transferring optical signals in mutually opposite directions. The optical transmission apparatus determines whether the identification information included in the header information of the received optical signal having the working wavelength matches pre-stored identification information. The optical transmission apparatus thus detects a fault that occurs by the communication path.

Abstract: This invention provides a fiber optic rotary joint (20) for enabling the transmission of digital optical signals across the interface between facing surfaces (26, 29) of a rotor and a stator (21, 22), comprising: a plurality of light sources (42A, 42B, 42C, . . .

Abstract: Even in a network system including a transmission line of which dominant cause of delay is a transmission line delay, controlling communication speed of the network system as a whole efficiently and suppressing the delay is made possible.

Abstract: The present disclosure provides systems and methods for administrative boundaries in a single domain optical network such as emulation of an External network-network interface (ENNI) using an Internal-Network to Network Interface (INNI). For example, in a single monolithic domain, a network and associated network elements may discover network elements, build topology, compute paths, establish new calls, etc. A user may identify/mark specific links as emulated “ENNI” links with the specific links actually being INNI links. As a call traverses this emulated link, a new call is initiated (much in the same way a new call segment would be created for a call). Signaling proceeds as normal. When the call set-up is fully complete, instead of a single call segment, many call segments exists. Advantageously, this allows use of INNI control plane features while allowing a network operator to future-proof their network by installing call segments at future boundary points.

Abstract: An optical transmission system transmits an optical signal of multi-level modulation. In a transmitter module, a data string in a specified frame is rearranged into a plurality of logical lanes. A lane ID, which specifies in what logical lane out of the plurality of logical lanes a start of the data string is arranged, is assigned to a non-scrambled area in an overhead portion of the frame. The lane ID corresponding to one of the plurality of logical lanes is different from the lane IDs corresponding to the other remaining logical lanes. The optical signal is generated using the data string rearranged into the plurality of logical lanes. In a receiver, the lane ID is detected according to a majority method. The inversion of bits and the swapping of lanes are detected using the lane ID and compensated.

Abstract: A network device provides a selector list that includes indices of child nexthops associated with the network device, where each of the child nexthops is associated with a corresponding child link provided in an aggregated bundle of child links. The network device also receives an indication of a failure of a child link in the aggregated bundle of child links, and removes, from the selector list, an index of a child nexthop associated with the failed child link. The network device further receives probabilities associated with the child links of the aggregated bundle of child links. Each of the probabilities indicates a probability of a packet exiting the network device on a child link. The network device also creates a distribution table based on the probabilities associated with the child links, and rearranges values provided in the distribution table.

Abstract: In an optical transmission system, a first monitoring section configured to monitor a first optical signal on a first optical transmission line to detect a first failure. A modulating section generates a second optical signal obtained through modulation of a signal corresponding to the first optical signal based on the first failure, to transmit the second optical signal onto a second optical transmission line which is connected with the first optical transmission line and a terminal unit. A second monitoring section monitors the second optical signal on the second optical transmission line to detect a second failure, and a detecting section detects the first failure from the second optical signal on the second optical transmission line.

Abstract: A network connection device for performing a process of transmitting and receiving a SONET/SDH frame includes a first protocol processor which processes a first network management protocol; a second protocol processor which processes a second network management protocol; a frame header extractor which extracts a header from the received SONET/SDH frame; and a protocol identifier which identifies a network management protocol based on the extracted frame header. The network connection device selects one of a control signal outputted from the first protocol processor and a control signal outputted from the second protocol processor based on a result of the identification, and outputs the control signal.

Abstract: A transmission apparatus includes a processor that is operative to terminate a first line performing a communication using a digital wrapper, to terminate a signal on a second line performing a communication using Gigabit Ethernet, to apply a transparent transcoding process to a terminated signal and the signal received from the second line and to output these signals; and wherein when a fault occurs in a communication performed through the first line and when there is no response for a predetermined time period after an auto negotiation restart signal is reported to an opposite apparatus on a second line side, to report information indicating an occurrence of the fault to the opposite apparatus by using a signal of a MAC (Media Access Control) frame format.

Abstract: An ONU includes the optical transceiver capable of an operation in a power-saving mode in which power consumption is reduced by stopping transmission while continuing reception, and a control device that controls to tentatively validate transmission of the optical transceiver and outputs a response signal when a control signal is received from an OLT during an operation in a power-saving state. Moreover, the OLT includes the control device that allocates a transmission bandwidth to the ONU even while the optical transceiver of the ONU operates in a power-saving mode and stops transmission and determines whether a communication failure occurs or the ONU is in operation in a power-saving mode based on the response signal received by a transceiver of the OLT.

Abstract: Apparatuses, systems, and methods of routing data through an optical network are disclosed. One such method includes transmitting optical data via a first fiber optic network from an originating node on a first level to a second level, receiving the optical data at a destination node on a third level from the second level via a second fiber optic network, wherein the second level, connected to the first fiber optic network and the second fiber optic network, includes a first intermediate node as a primary route on the second level for transmitting the optical data from the originating node to the destination node, and a second intermediate node as an alternate route on the second level for transmitting the optical data from the originating node to the destination node when the first intermediate node fails.

Abstract: An interface between a network component and an optical fiber section communicates with a remote interface and a remote network component at an opposite end of the optical fiber section through over-modulation of optical signals sent between the interfaces and network components. The over-modulation is at frequencies much lower than the ordinary modulation of the optical signals. The over-modulation allows communication between the interfaces for performing management, testing and maintenance operations and permits superior detection of faults in the optical fiber section.

Abstract: The present invention discloses a method for indicating client signal fail in an optical transport network, including: adding CSF indication bits to an Optical Channel Payload Unit k (OPUk) or/and OPUk-Xv multiframe to indicate whether a client signal is failed; detecting the CSF indication bits of a PSI in the received OPUk or/and OPUk-Xv multiframe, and when the number of continuously detected CSF indications exceeds a preset threshold, indicating to perform a link protection switch. The present invention also discloses an apparatus for implementing the above method. The present invention can avoid the case of APS fail due to the too long CSF time delay; the indication method is simple and the implementation is convenient; and a plurality of CSF indications are used in the multiframe, thus the indication is more flexible.

Abstract: A level transition determination circuit includes a multi-phase clock generator, an oversampling unit, and a state detection circuit. The multi-phase clock generator is used for receiving an input clock signal and generating S×N clock signals, in which S and N are integers. Each clock signal is synchronized to the input clock signal and has a different delay time. The oversampling unit is used for performing N-times oversampling on M bit periods of the serial input data according to the clock signals, so as to generate M×N sampled values in parallel during the M bit periods. The state detection circuit is used for receiving (M×N)+1 sampled values and generating N detection signals by detecting level transitions between adjacent sampled values of the (M×N)+1 sampled values and the level transition results.

Abstract: An image compression apparatus includes: first and second imaging sections for capturing an image of a subject to generate first and second image signals, respectively; first and second encoding sections for encoding the first and second image signals to generate first and second image data, respectively; first and second distance measuring sections for measuring a distance to the subject for each of image blocks, at the same time as the first and second imaging sections perform image capturing, to generate first and second distance information, respectively; first and second multiplexing sections for generating first and second multiplexed data on the basis of the first and second image data and the distance, respectively, by respectively multiplexing the first and second image data and first and second distance data, which are generated on the basis of the first and second distance information and indicate the distance to the subject for each of predefined pixel blocks in the first and second image data, re

Abstract: A method for recovering an OTUk frame includes: receiving an optical signal sent by using a method of multi-lane distribution from the OTUk frame to an interface of an optical module; converting the optical signal into an electrical signal, performing electrical equalization and demodulation on the electrical signal, and recovering multi-lane data from the demodulated signal; aligning and rearranging the data on each lane, according to a lane sequence identifier included in an overhead frame header of the data on each lane; and recovering the OTUk frame according to the aligned and rearranged data. According to the present invention, lane rearrangement is performed by detecting the lane sequence identifier, and the recovery of the OTUk frame is achieved. Therefore, a training sequence overhead does not need to be additionally introduced, and the influence on the system performance is avoided.

Abstract: A method for clearing a fault condition at a target device is disclosed herein. In selected embodiments, such a method includes detecting a fault condition at a target device and receiving N instructions before the fault condition is cleared, where the N instructions are unexecutable due to the fault condition. N fault condition indicators are transmitted in response to the N instructions. Clearing of the fault condition is detected when the fault condition no longer exists. Acknowledgments corresponding to the fault condition indicators are received, where each acknowledgment indicates that one of the fault condition indicators has been received. A fault clear indicator is transmitted only after both all N fault condition indicators have been received and clearing of the fault condition has been detected. A corresponding system and computer program product are also disclosed herein.

Abstract: The present invention relates to an optical fiber access network and a communication protection method thereof. The optical fiber access network comprises an optical fiber communication system, a wireless communication system, a communication service switch device, a second optical network unit and a protection optical fiber. The wireless communication system is introduced to protect the optical fiber between the optical branching divider and the optical network unit in the optical fiber communication system. The protection optical fiber or the wireless communication system is used to protect the communication service respectively when there is a broken failure between the optical line terminal and the optical network unit in the optical fiber communication system. This invention overcomes the limit of the resource, protects communication service of the optical fiber communication system and improves the bandwidth utility of the communication system.

Abstract: A method is provided for protection switching in an optical network. The method may include communicating a switch request for initiation of protection switching in response to a determination that at least a minimum frequency of interrupts indicating failure of an optical signal has occurred over a first period. The method may also include communicating a switch request for cessation of protection switching in response to a determination that no more than a maximum frequency of interrupts indicating failure of an optical signal has occurred over a second period.

Abstract: The present invention discloses a method for instructing enabling/disabling Forward Error Correction (FEC) function. The method comprises: presetting an instruction identifier of an FEC status; transmitting an instruction identifier of an FEC status of an Optical Network Unit (ONU) and the Identity (ID) of the ONU by an Optical Line Terminal (OLT), wherein the instruction identifier of the FEC status of the ONU is corresponding to the ID of the ONU; and enabling or disabling its own FEC function by the ONU according to the received instruction identifier corresponding to its own ID. The present invention also discloses a system for instructing enabling/disabling FEC function, which comprises an OLT and an ONU. The method and system of the present invention can solve the problem that the ONU cannot determine the instruction from the OLT due to an error code.

Abstract: In a fiber-optic communications system, a backup or redundant optical link is provided at the central office in parallel with the primary one in use. Parameters associated with the backup link, including its signal delay, its attenuation, etc. are stored at the time of installation. Upon failure of the primary link, switchover can be automatic, and the stored parameters are used to make adjustments necessary for the differences between the primary link and the backup link. In addition, having information on the differences between the two links, the central office is able to send control information downstream which is used at the remote site to control changes that must be made for upstream signals. For example, customer equipment can be signaled to adjust its timing for the next time slot or interface amplifiers can be adjusted to account for the change in attenuation.

Abstract: In one embodiment, a coherent optical receiver has a digital signal processor that processes one or more digital I/Q-signal pairs to recover data carried by a modulated optical signal in a manner that mitigates, based on calibration data retrieved from a memory or on appropriate performance measures and feedback mechanisms, the detrimental effects of frequency-dependent imbalances between the I and Q sub-channels of at least one of the I/Q channels of the receiver. In various embodiments, the calibration data can be generated and written into the memory at the fabrication facility or in situ while the receiver is being operated in a calibration mode. Alternatively or in addition, the calibration data can be generated and dynamically adjusted online during normal operation of the receiver.

Abstract: An ONU that receives a discovery gate transmitted by an OLT in a predetermined cycle, returns a response signal in response to the discovery gate, and receives a unicast frame transmitted to the ONU by the OLT having received the response signal, comprising: a received frame detecting unit that detects whether a signal received from the OLT is a discovery gate or a unicast frame; and an erroneous emission detecting unit that detects an abnormal emission state, based on a result detected by the received frame detecting unit.

Abstract: A method, system, and computer program product for connection state recovery of a connection after fault in a networked channel-to-channel computer system are provided. The method includes identifying essential data in response to detecting a state change in a channel of the computer system, the essential data including connection state information used in performing a recovery operation. The method also includes separating the essential data from transient or incidental data, augmenting the essential data with validation data, and storing the augmented essential data in a memory location of a control unit in communication with the channel. In response to initiation of a recovery operation, the method includes retrieving the augmented essential data and validating contents of persistent data fields containing the essential data. The method further includes using the contents to restore the connection to an operational state when it is determined that the contents of the persistent data fields are valid.

Abstract: An Optical Network Unit (ONU) in a Passive Optical Network (PON), the ONU comprising: a receiver module configured to receive a first rate selection signal from an optical line terminal (OLT) that indicates a reduced rate mode, and a component comprised within the receiver module, the component configured to transition from a normal operation mode to the reduced rate mode in response to the receiver module receiving the first rate selection signal, wherein operating in the normal operation mode comprises receiving a downstream signal from the OLT at a nominal data rate, and wherein operating in the reduced rate mode comprises receiving the downstream signal from the OLT at a reduced data rate that is less than the nominal data rate but greater than zero.

Abstract: The present invention enables to prevent transmission characteristics from deteriorating due to the nonlinear effect in the transmission path caused by an increase in the channel power when a cable disconnection occurs.

Abstract: An RF signal processing device which includes a countermeasure set connected to the processing device. The RF signal processing device shifts an incoming RF signal by ninety degrees and combines the phase shifted RF signal with RF jamming signals from a jammer. The processing device next transmits the RF signal including the RF jamming signals from the jammer.

Abstract: Systems and methods of polarizaton demultiplexing are disclosed. One such method receives a transmitted polarization-multiplexed optical signal The polarization-multiplexed has multiple polarizations, each of which represents an independent data stream. The method converts the polarization-multiplexed optical signal to a corresponding polarization-multiplexed electrical signal. The method determines an inverse transformation matrix that meets an independent component analysis (ICA) criterion. The method applies the inverse transformation matrix to the polarization-multiplexed electrical signal, which produces a polarization-demultiplexed electrical signal. The method phase estimates the polarization-demultiplexed electrical signal to recover the data stream.

Abstract: A method and apparatus for restoration of operating conditions of a WDM optical ring network comprising a plurality of amplifiers linked together in a ring after a break or fault has occurred in the network. The method comprises in response to repair of the break or other fault, increasing output power or/and pump power of an amplifier in the network such that the output power or/and pump power increases substantially in accordance with a ramp function.

Abstract: A network element of an optical communications network. The network element comprises an electronic router for forwarding traffic between a set of client access ports and a plurality of I/O ports. A respective EO interface is coupled to each one of the plurality of I/O ports. Each EO interface terminates a respective optical channel. A directionally independent access (DIA) node is configured to selectively route each optical channel between its respective EO interface and a selected one of at least two optical fiber links of the optical communications network.

Abstract: An object of the present invention is to continue to send and receive to/from a host when a failure has occurred in a storage device interface. A storage system includes a host and a storage device connected to the host via a communication line, wherein the storage device comprises a communication controller performing data communication with the host by using optical modules, and wherein the communication controller is provided with first optical modules performing data communication with the host; a second optical module performing data communication with the host, in place of a first optical module; and a controller switching, when a failure has occurred in any of the first optical modules, the first optical module in which the failure has occurred to the second optical module.

Abstract: Interworking an Ethernet Ring network with an Ethernet network with traffic engineered trunks (PBT network) enables traffic engineered trunks to be dual homed to the Ethernet ring network to enable for protection switching between active and backup trunk paths in the PBT network. In one embodiment, the active path will terminate at a first bridge node on the Ethernet ring network and the backup path will terminate at a second bridge node on the Ethernet ring network. Trunk state information is exchanged between the bridge nodes to enable the bridge nodes to determine which of the active and backup paths should be used to forward data on the trunk. Upon a change in trunk state, a flush message is transmitted on the Ethernet ring network to enable the nodes on the Ethernet ring network to relearn the path to the new responsible bridge node.

Abstract: A network device provides a selector list that includes indices of child nexthops associated with the network device, where each of the child nexthops is associated with a corresponding child link provided in an aggregated bundle of child links. The network device also receives an indication of a failure of a child link in the aggregated bundle of child links, and removes, from the selector list, an index of a child nexthop associated with the failed child link. The network device further receives probabilities associated with the child links of the aggregated bundle of child links. Each of the probabilities indicates a probability of a packet exiting the network device on a child link. The network device also creates a distribution table based on the probabilities associated with the child links, and rearranges values provided in the distribution table.

Abstract: A flexible open ring optical network includes a plurality of nodes connected by twin or other suitable optical rings. Each node is operable to passively add and passively drop traffic from the rings. The nodes may include a transport element for each ring. The transport elements include an optical splitter element and an optical combiner element. The optical splitter element is operable to passively combine an add signal including local add traffic and a first transport signal including ingress traffic from a coupled optical ring to generate a second transport signal including egress traffic for transmission on the coupled optical ring. The optical combiner element is coupled to the optical splitter element and is operable to passively split a third transport signal including the ingress traffic to generate a drop signal including local drop traffic and a fourth transport signal including the ingress traffic.

Abstract: An apparatus comprising an optical line terminal (OLT) configured to couple to a plurality of optical network units (ONUs) and transmit a plurality of downstream frames to the ONUs, wherein each of the downstream frames comprises a plurality of forward error correction (FEC) codewords and a plurality of additional non-FEC encoded bytes that comprise synchronization information that is protected by Header Error Control (HEC) code. An apparatus comprising a processing unit configured to arrange control data, user data, or both into a plurality of FEC codewords in a downstream frame and arrange a physical synchronization sequence (PSync), a superframe structure, and a Passive Optical Network-identifier (PON-ID) structure in a plurality of additional non-FEC encoded bytes in the downstream frame, and a transmission unit configured to transmit the FEC codewords and the additional non-FEC encoded bytes in the downstream frame within a 125 microsecond window.

Abstract: Transport network interfaces operate to transport for Optical Transport Unit frames over an Optical Transport Network. Besides FEC bits for the Optical Transport Unit frames, the transmitting transport network interface provides sequences of error-determining bits for the Optical Transport Unit frames sent on working and protection communications channels. There is at least one sequence for each Optical Transport Unit frame, the number of bits in the at least one sequence much smaller than the number of bits in the Optical Transport Unit frame. The receiving transport network interface determines the bit error rates for the working and protection channels from the sequences of error-determining bits without decoding said Forward Error Correction bits and can select the working and protection channels accordingly.

Abstract: A method is provided for dispersion compensation of an optical signal communicated in an optical network. The method may include receiving an optical signal comprising a plurality of channels. The method may further include filtering at least one channel from the plurality of channels. The method may also include analyzing the at least one channel of the plurality of channels to measure optical dispersion in the at least one channel. The method may additionally include compensating for optical dispersion based on the measured dispersion.

Abstract: Methods and systems are provided for compensating impairment of a signal in an optical network. A method may include: (i) recording, for each node of a plurality nodes of the network, traffic management information specific to such node; (ii) communicating, by each node, its associated traffic management information to one or more other nodes; (iii) receiving, at a particular node of the plurality of nodes, the traffic management information communicated from the one or more nodes; (iv) determining, by the particular node, digital signal processor tap coefficients for a digital coherent receiver integral to the particular node based on at least a portion of the traffic management information; and (v) compensating, by the digital coherent receiver, optical impairment of the optical signal based on at least the determined digital signal processor tap coefficients and processing of the optical signal by a digital signal processor integral to the digital coherent receiver.

Abstract: An apparatus includes a first estimator that estimates a signal quality based on an error correction number of an electrical signal obtained by photoelectrically converting a received optical signal; a second estimator that estimates a signal quality from which the influence of nonlinear effects is removed based on signals upstream and downstream of an identification calculator identifying the electrical signal; and a calculator that calculates the difference between the signal qualities estimated by the first and second estimators to calculate the amount of nonlinear effects.

Abstract: A method for sending uplink burst data in a passive optical network (PON) system includes: sending a synchronization pattern of the uplink burst data, the synchronization pattern being of a length, which is an integer multiple of 66 bits, and being formed by connection of 66-bit unit gene blocks; sending a burst delimiter (BD) of the uplink burst data; sending a forward error correction (FEC)-protected data in the uplink burst data; and sending an end of burst (EOB) delimiter of the uplink burst data. The technical solutions in the embodiments allow the use of a less complex equalizer at the reception end of a high-speed PON system.

Abstract: An optical axis adjusting apparatus for an optical device includes a drive unit moving an optical component through which communication light emitted from a light source passes, a plate member disposed facing the optical component, the plate member allowing light to transmit through the plate member and reflecting light to the optical component, a photographing unit disposed on a back side of the plate member, taking an image irradiated with the light transmitted through the plate member, and a control section controlling the drive unit to move the optical component based on the image and information on optical characteristics of the light reflected by the plate member.

Abstract: An OCDM communication system and a method for correcting failure of the same are provided. In the system, encoders and decoders are provided respectively for channels. Each encoder, including an SSFBG, encodes an optical signal using a code value determined according to distance between adjacent unit fiber Bragg gratings in the SFFBG. Each decoder, including an SFFBG, generates a received optical signal by decoding the encoded signal using a code value determined in the same manner. A set temperature of each encoder and decoder is calculated and a corresponding control signal is generated based on average power and error rate detection signals of each received optical signal. The temperature of each encoder or decoder is individually adjusted according to the control signal, which makes equal the code values of an encoder and decoder of a channel in which average power of a received signal has changed or error rate thereof is excessive.

Abstract: A method and system for distributed fault sensing and recovery in a communication system. A master controller is provided in each cable station of the system. Each master controller receives local alarms, e.g. aggregated alarms from associated shelf controllers, and may receive remote alarms from other master controllers. Local and remote alarms are compared to a profile provisioned in the master controllers for determining whether to perform a fault recovery function.

Abstract: A transmitting apparatus obtains cross-connect information on an input side and an output side, reserves the information as a cross-connect for management shift, adds object information formed of that cross-connect information and others to a signaling message for transmission and reception, and also updates the reserved cross-connect for management shift to shift path management.

Abstract: The present invention relates to a method and devices for fast protection of an optical network system, in particular for a Passive Optical Network (PON), such as a Gigabit-capable Passive Optical Network (GPON). In the method, it is detected that the communication from a first optical network device is lost. Switching of functionality is initiated from a first optical line termination device to a second optical line termination device, and a control message is sent from the second optical line termination device to the first optical network device such that the first optical network device is prevented from moving into initial state. Furthermore, the method comprises determining and setting timing settings for the first optical network device.