Abstract: Due to demand for more network bandwidth, a need for multi-user optical network topologies has, and will continue to, increase. A method or corresponding apparatus in embodiments of the present invention provide for an availability determination tool for determining and displaying wavelength and subrate availabilities within a network. Benefits of embodiments of a tool include allowing a user to identify the availability and capacity of any wavelength on any network, via an interactive graphical user interface, such as by using three-dimensional representations. In one embodiment, the disclosed availability determination tool allows users to locate and view any combination of available wavelengths between nodes in an optical network topology, and generate graphical and tabular reports of the availability in order to maintain an efficient and organized method or apparatus for determining and controlling wavelengths in a network.

Abstract: The present invention relates to a method, device and system 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, communication failure between a first optical network device and a first optical line termination device is detected. Switching of functionality from the first optical line termination device to a second optical line termination device is initiated, 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.

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.

Abstract: An optical transmission apparatus includes a transmitter that transmits to a counterpart receiver via a transmission path and transmits as optical signals for a plurality of channels, input signals for a plurality of channels; and a controller that when a transmission failure between the transmitter and the receiver is detected, distributes to properly operating channels, data for a channel subject to the transmission failure, increases a transmission rate for the properly operating channels to a given transmission rate, and continues data transmission for all channels including the channel subject to the transmission failure.

Abstract: Optical networks occasionally experience a fault along a communications path. Service providers prefer to have an alternative communications path available to enable users to still communicate in a seamless manner. Accordingly, a method and corresponding apparatus for providing path protection for dedicated paths in an optical network is provided.

Abstract: The invention relates to a method for performing a switch operation between a first Optical Line Terminal OLT and a second OLT in a Passive Optical Network PON, said first and second OLTs being connected to a plurality of Optical Network Units ONUs through at least one splitter. The invention enables to avoid the detection of a timestamp drift error during protection switching operation by modifying the threshold of the detection in the second OLT.

Abstract: When a failure occurs in operational transmission multiplexing transponders 6-1 to 6-N, a wavelength multiplexing optical transmission system carries out selection switching control on N×1 optical switches 5-1 to 5-m and (N+1)×1 optical switches 11-1 to 11-m to transmit a wavelength-multiplexed light signal by using reserve transmission and reception multiplexing transponders 6-R and 10-R, thereby sidestepping the failure.

Abstract: In a broadband access network, calls can be kept active even when a telephone network fails. A voice gateway function captures callee telephone number information sent from a caller subscriber telephone to the telephone network and, when the telephone network fails, keeps the call active by retaining the connection between the caller and the callee. Furthermore, when the telephone network fails, the operation mode of the voice gateway and all ONTs is switched from an H.248 gateway mode to an SIP softswitch mode, allowing the voice gateway function to relay communication packets between ONTs and new call connections to be made in the broadband access network.

Abstract: A connection-oriented optical network (2) comprises nodes (10) and optical links (5) between nodes. Each node (10) has a power control unit (60) for controlling an optical amplifier (43) at the node. A node, in response to a requirement to set up a new connection in the network, signals to a power control unit (60) at each of a plurality of downstream nodes along a path of the new connection to cause the power control unit at the node to adjust the optical amplifier at the node to support a new optical channel to carry the new connection. The node (10) can signal to tear down an existing connection in a similar way. A downstream node determines a number of optical channels for which the optical amplifier can be adjusted concurrently, based on an existing number of active optical channels.

Abstract: A transmission apparatus interconnects a core network for making a communication by forming a connection and a metro network for m a communication by adding an address to data and by executing a forwarding process. The transmission apparatus includes a function of transmitting the data to the connection of the core network, to which an address of the metro network is made to correspond, and transfers the data to the connection of the core network, which is made to correspond to the address added to the data received from the metro network.

Abstract: A protection switching method of packet-optical combined switching system in accordance with the inventive concept may include detecting whether or not an obstacle occurs in a packet path; performing a first protection switching using a preliminary path if an obstacle is detected from the packet path; generating an imaginary preliminary path using a preliminary resource of optical path when the first protection switching is failed; and performing a second protection switching using the imaginary preliminary path.

Abstract: Systems, methods and apparatus for operating an optical network terminal (ONT) in a passive optical network include maintaining an operational state in the passive optical network, estimating an upstream channel, adjusting equalization delay and physical layer frame offset values and switching from a backup mode to a primary mode of operation upon detecting a failure condition.

Abstract: A system for serving N optical communication lines by a redundant set of modules in an optical network; where the set of modules comprises N>1 main modules and one backup module, N optical splitters, 2N fiber connections and a control means. In the system, each of the N optical splitters is connected to two different modules of the set by two respective fiber connections out of the 2N connections, while each of the N optical splitters is also coupled to one of the N optical communication lines. The arrangement is such that the control means selectively activates/inactivates any of the fiber connections for respectively enabling/blocking transfer of data there-along; the control means thus ensures that each specific line of the N optical communication lines is always served by either one or another of two different modules.

Abstract: In an embodiment, a dual optical-electrical conversion (DOEC) module is described that includes an optical host interface, an optical network interface, and an integrated circuit. The optical host interface includes an optical transmitter and an optical receiver. The optical network interface includes an optical transmitter and an optical receiver. The integrated circuit conditions electrical signals communicated between the optical host interface and optical network interface. Optical signals received at and transmitted by the optical host interface may have different parameter requirements than optical signals received at and transmitted by the optical network interface, such as such as different wavelength parameters and/or fiber link length parameters.

Abstract: A plurality of transmission devices are communicably coupled to each other in a first transmission network. A first transmission device receives data from a second transmission device, and extracts, from the received data, attribute information including report-destination identification information identifying a third transmission device and routing information identifying a transmission route through which the data has been transmitted to the first transmission device via the second transmission device in the first transmission network.

Abstract: The present invention discloses a linear protection method for an optical network, used for protecting a failed service path in the optical network, and the method comprises: setting priorities of services carried on service paths participating in linear protection of the optical network as service priorities; selecting, from the service paths participating in the linear protection, a service path of which the service priority is lower than that of the failed service path as a protection path, and bridge switching the service on the failed service path to the protection path. The present invention implements protection of service paths according to the priority of the service carried on the failed service path, and enhances the security of service paths.

Abstract: An amplifier node, in an optical network, includes a first switch connected to a working path from which network traffic is received; a second switch connected to the working path to which the network traffic is transmitted; and two amplifiers that interconnect the first switch and the second switch, where the network traffic travels from the first switch to the second switch via a first amplifier. The amplifier node also includes a controller to receive an instruction to switch the network traffic from the first amplifier to a second amplifier that enables the first amplifier to be repaired; send, to the first switch and the second switch, another instruction to switch the network traffic from the first amplifier to the second amplifier; receive an indication that the network traffic is traveling via the second amplifier; and send a notification that the first amplifier can be repaired based on the indication.

Abstract: Embodiments of the present disclosure provide a data synchronization method and system, and an optical network unit. An ONU receives synchronization data that is transmitted by a first OLT through a GEM port corresponding to a predetermined GEM port ID or a logical link corresponding to a predetermined LLID, and stores the synchronization data. When a fault occurs on the first OLT or on a backbone optical fiber connected to the first OLT, the ONU transmits the synchronization data to a second OLT so that the second OLT recovers services according to the synchronization data.

Abstract: The present invention discloses a passive optical network (PON) protection method, a switchover control device, and a PON protection system. In embodiments of the present invention, a protection optical line terminal (OLT) is connected to optical links of at least two working OLTs through the switchover control device; when a working OLT or working optical link fails, the switchover control device replaces the working OLT through the protection optical link, thus ensuring smooth communication. In addition, by using the networking mode of multiple working OLTs and one protection OLT, the embodiments of the present invention greatly saves the networking cost and facilitates the application of the PON technology.

Abstract: Methods, systems, and computer-readable media provide for notifying an optical line termination (OLT) of a power failure. According to embodiments, a method for notifying an OLT of a power failure is provided. According to the method, a notification of a power failure at an optical network termination (ONT) is received. In response to receiving the notification, power is retrieved from a dedicated power storage unit dedicated to providing power for the transmission of a dying gasp alarm. The dying gasp alarm is transmitted to the OLT utilizing at least a portion of the power from the dedicated power storage unit. The dying gasp alarm notifies the OLT of the power failure.

Abstract: In accordance with embodiments of the present disclosure, a method may include sorting potential optical layer link failures in a network in an increasing order of failed traffic amount. The method may further include, for each potential optical link failure in increasing order of failed traffic amount: determining the additional higher layer link capacity required on existing higher layer links associated with the potential optical link failure using higher layer restoration of the potential optical link failure; determining the additional optical layer capacity required for restoring the existing higher layer links associated with the potential optical link failure using optical layer restoration; and selecting one of the higher layer and the optical layer as a restoration layer for restoration of the existing higher layer links associated with the potential optical link failure based on the determined additional higher layer link capacity and the determined additional optical layer capacity.

Abstract: Method and arrangement for protecting optical network systems, the arrangement (20) is based on an optical electrical optical GPON repeater structure. The repeater structure contains two optical modules—a regular ONU transceiver module and a reset-less OLT transceiver module which are working back-to-back. For management purposes, an ONU MAC module comprised in the repeater structure is intercepting the electrical signals from the ONU transceiver. The arrangement comprising the two repeater structures can be used to relay data between two passive optical network (PON) systems thereby opening a way to implement dual homing via the PON domain. Moreover, the arrangement is configured to enabling switch-over of functionality from one PON to the other PON at a communication failure in the former PON.

Abstract: A communication system includes a synchronous interface coupled to a switch fabric; cells for switching; and a 1+1 protection unit with a primary and back-up line cards.

Abstract: A system to provide hitless protection includes a primary line card with a synchronous interface, the primary line card processing traffic with cells and encapsulating the traffic into synchronous frames in a predetermined format; and a back-up line card with a synchronous interface, the back-up line card processing the traffic with the cells and encapsulating the traffic into the synchronous frames in the predetermined format, wherein each line card includes a buffer to align the traffic before transmission, wherein the cell information sent by the primary line card is passed to the back-up line card, and wherein the back-up line card follows the received information to send to the destination cell.

Abstract: An optical transmission device includes a wavelength multiplexing/demultiplexing unit, a plurality of transponders, an optical switch unit and a controller. The controller includes a table in which a plurality of items at least including priority order, a transmission label, a receiving label and a receiving label expected value correspond to the respective transponders. And the controller rewrites the transmission label of the transponder corresponding to the client device of the lower priority order than the priority order of the client device connected to the transponder of the irregular input, upon the optical signal provided by the wavelength multiplexing/demultiplexing unit to one of the transponders being irregular, and controls the label-changed transponder for which the transmission label has been rewritten so that the label-changed transponder provides the wavelength multiplexing/demultiplexing unit with the optical signal including the rewritten transmission label.

Abstract: Fault tolerance may be achieved in a branched optical communication system such that a fault in one optical path may not affect optical signals coupled from a healthy optical path. In general, a flexible branching unit is configured, when adding and dropping channels, to select channels from a healthy path and not from the faulty path (e.g., a trunk path or a branch path) to prevent non-uniform channel loading on the trunk path after the branching unit. In this manner, a fault detected on the trunk path may not affect signals from the branch path and a fault detected on the branch path may not affect signals from the trunk path, thereby providing fault tolerance. A flexible branching unit may also be capable of adjusting the number and selection of channels that are added and dropped at the branching unit.

Abstract: The present invention discloses a passive optical network (PON) protection method, a switchover control device, and a PON protection system. In embodiments of the present invention, a protection optical line terminal (OLT) is connected to optical links of at least two working OLTs through the switchover control device; when a working OLT or working optical link fails, the switchover control device replaces the working OLT through the protection optical link, thus ensuring smooth communication. In addition, by using the networking mode of multiple working OLTs and one protection OLT, the embodiments of the present invention greatly saves the networking cost and facilitates the application of the PON technology.

Abstract: First and second switching device are connected by a number of signal paths. The first switching device receives an instruction to switch from a first one of the signal paths to a second one of the signal paths. The first switching device performs, in response to the received instruction, a first switching operation to connect the first path, at an input of the first switching device, to the second path, at an output of the first switching device. The second switching device receives the instruction to switch from the first path to the second path and detects a loss of signal on the first path as a result of the first switching operation performed by the first switching device. The second device performs, in response to detecting the loss of signal on the first path, a second switching operation to connect the first path, at an output of the second switching device, to the second path, at an input of the second switching device.

Abstract: This invention discloses a method and an apparatus for transmitting/receiving signals in a microwave system, and pertains to the field of communications. The transmitting method comprises receiving and modulating a transmission signal transmitted via an optical fiber; processing the modulated transmission signal to generate RF signal; and separating the RF signal to be transmitted from a signal received via an antenna, and transmitting the separated RF signal via the antenna. The receiving method comprises separating a signal received via an antenna from a signal to be transmitted; processing the received signal after being separated to generate IF signal; demodulating the generated IF signal; and transmitting the received signal after being demodulated via an optical fiber. The transmitting/receiving apparatus comprises an optical fiber signal interface, a signal reception module, a modulation module, an IF-RF transmission module, a duplexer, a control module and a power interface.

Abstract: A method may include: (i) provisioning a first network-side interface of a first plug-in unit and a second network-side interface of a second plug-in unit as members of a network-side protection group, the first plug-in unit and the second plug-in unit integral to an adaptation layer network element; (ii) provisioning a first client-side interface of the first plug-in unit and a second client-side interface of the second plug-in unit as members of a client-side protection group; (iii) designating one of the first and second network-side interface as an active network-side interface of the network-side protection group; and (iv) designating one of the first second client-side interface as an active client-side interface of the client-side protection group, such that traffic ingressing on the active network-side interface may egress on the active client-side interface and traffic ingressing on the active client-side interface may egress on the active network-side interface.

Abstract: A network protection switching mechanism comprises a plurality of optical switches located at a plurality of nodes; a plurality of optical communication paths between said switches; switch based fault detectors located as part of at least two switches which generate detection results representative of the identification of a fault; switch based controllers located as part of said at least two switches; and internal switch-communication means between said fault detectors and said controllers which facilitate the transmission of detection results from said fault detectors to said controllers; wherein said controllers directly cause switching to an alternative optical communication path dependent upon the receipt of said detection results; whereby autonomous switch based protection without dependence on either inter-switch control communication or higher level network control communication is achieved.

Abstract: In a transmission apparatus, unlike in the conventional transmission apparatus, a protection switch is not arranged on the signal path, but a TSI having only the basic function performs the function of the protection switch as a substitute, a processing unit to perform the switching function at a low rate is artificially constructed on a TSI, the switch process of SONET protection type is artificially executed by the TSI, and a signal for controlling the TSI function is further controlled thereby to realize the protection switch function. The logic of switching at the main signal rate in addition to the conventional TSI function is deleted.

Abstract: The present disclosure provides hybrid packet-optical private network systems and methods for a private and dedicated multi-point Ethernet Private Local Area Network (EPLAN). The network systems and methods include a Layer 1 infrastructure service with the inclusion of reserved, dedicated packet switch capacity upon which clients can build their personal, private packet networks. In the systems and methods described herein, packet networking methods are not used to partition the isolated LAN connectivity. Instead, dedicated Ethernet Private LANs (EPLs) are defined between dedicated virtual switching instances (VSIs) that are defined, as necessary, within larger packet-optical switches. Each VSI is partitioned from the remainder of its packet switch fabric as a dedicated, private resource for a specific EPLAN. A packet network is then built by the customer on top of the private EPLAN bandwidth and operated as an isolated, private network with no influence by other carrier's network resources.

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: Optical By-Pass (OBP) links may be created by adding wavelengths between nodes on the network. The OBP may extend between any pair of nodes on the network. Intermediate nodes on the OBP are transient nodes and simply forward traffic optically. An OBP extends between a pair of nodes and, unlike express links, is created in such a manner that it does not affect the previous allocation of resources on the network. This enables capacity to be added between pairs of nodes on the network to alleviate congestion at a portion of the network, without changing other traffic patterns on the network. This enables inclusion of an OBP to be deterministic and of linear impact on the network. The OBP links may be statically provisioned or created on demand. Optionally, the OBP links may be crated to coincide with PBB-TE tunnels on the network.

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: When the provider edge PE1 detects the occurrence of a failure at the access line AL1, it sends the label withdraw message to the virtual circuit VC1, and when the provider edge PE2 receives the label withdraw message sent via the virtual circuit VC1, the access line AL2 is put to a link down state, and when the customer edge CE2 detects the link down state of the access line AL2, it switches from the normal path to the redundant path.

Abstract: A network apparatus includes: an input interface unit; a first and second line switching units cross-connecting output signals from the input interface unit; an output interface unit including a selection unit selecting outputs from the first or second line switching units; and a CPU. The line switching units each include: a control signal generation unit storing setting data in a memory and generating a line switching control signal based on the setting data; a memory error detection processing unit detecting a memory error and outputting error information; and a main signal processing unit writing setting data into a buffer when an error is not detected, and holding setting data stored in the buffer when the error is detected, and which performs cross-connection processing according to the setting data stored in the buffer. The CPU controls the selection unit according to the error information.

Abstract: To detect the performance degradation of an optical communication transmission system after it becoming operational, thereby preventing the reliability of the system from lowering. In an optical communication transmission system, one of optical transmitter-receivers in a redundant-structured system is an active optical transmitter-receiver, and the other optical transmitter-receiver is a standby optical transmitter-receiver. The optical transmitter-receiver includes a loopback device through which the signal light of a transmitting section of the optical transmitter-receivers is inputted to a receiving section, and an operating-system switching scheduling device for regularly switching the operating system is provided.

Abstract: An optical network system that performs transmission of N:1 protection includes a node that includes transmission-side operating muxponders that multiplex client signals for every M-channel signal bundle and convert multiplexed signals into optical signals having different wavelengths, transmission-side optical couplers that branch the client signals into two channels of operating and redundant, transmission-side optical switches each selecting one channel from redundant signals as a redundant client signal, and a transmission-side redundant muxponder that performs a predetermined transmission-side process according to an accommodation mode set on the redundant client signal and then multiplexes the redundant client signals, converts the multiplexed signal into an optical signal having a wavelength different from that of the operating signal, thereby making the accommodation mode settable for each channel in an independent manner.

Abstract: Methods, systems, and products are disclosed for email management and rendering, including receiving aggregated email in native form, synthesizing the aggregated native form email into synthesized email, and presenting the synthesized email. Synthesizing the aggregated native form email into a synthesized email may also include translating aspects of the native form email into text and markup. Synthesizing the aggregated native form email into a synthesized email may also include identifying attachments to the aggregated native form email and translating aspects of the attachments into text and markup. Presenting the synthesized email also includes identifying a presentation action in dependence upon presentation rules and executing the presentation action.

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 method for channel protection switching of an optical network device, an Optical Transport Network (OTN) device, and a Passive Optical Network (PON) device is provided. The method includes detecting, by the PON device, whether an OTN alarm indication signal is received after discovering a fault. If the OTN alarm indication signal is received, the alarm generated by the PON device is suppressed so that the PON device does not perform channel protection switching. The PON device detects whether an OTN alarm indication signal is received, and suppresses the alarm generated by the PON device so that the PON does not generate futile alarms or lead to futile switching when the OTN fails but the PON works normally.

Abstract: A method of processing data for computing alternative paths in an optical network (10, 40) including making a list of groups (12, 14, 16, 18, 20, 22, 24, 26) that comprise links wherein the links in a group share a risk of being affected by the same fault, comparing each group (12, 14, 16, 18, 20, 22, 24, 26) with other groups (12, 14, 16, 18, 20, 22, 24, 26) in the list to determine whether each group includes the same links as another group, and deleting the groups (16, 26, 20, 22) that comprise links which are a subset of the links in another group.

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: A method for discovering neighboring nodes includes establishing a first optical connection with a first node using a first link. The method also includes detecting a change in the first optical connection. The method further includes initiating a discovery process to detect whether the first node or a second node is using the first link. The method additionally includes, upon detecting a second node using the first link, disabling the first optical connection and establishing a second optical connection with the second node.

Abstract: A system, method and computer readable medium comprising instructions for sending a message from an Optical Network Terminal (ONT) to an Optical Line Terminal (OLT), if the ONT does not receive an expected OLT action or an expected OLT response to the message within a period, considering the non-receipt of the expected OLT action or the expected OLT response a failure, and if a certain number of consecutive failures have occurred, considering by the ONT that it has entered an uncontrolled state.

Abstract: The disclosure discloses an apparatus and method for rerouting multiple traffics.

Abstract: The present invention discloses a distributed electrical cross apparatus, and a system and method for the distributed electrical cross apparatus implementing an SNC cascade protection. The apparatus includes a backboard and at least four single-boards integrated with electrical cross units, wherein the single-boards are inserted in the limited number of slots in the backboard, and these single-boards also set line-side service access units, client-side service access units and backboard access units. The present invention has both accessing of line-side services and accessing of client-side services in the same single-board, access and flexible scheduling of various services such as line-side services and client-side services and so on are implemented on the backboard with limited number of slots, and the function of the distributed electrical cross system processing various services is increased in the case of low cost.

Abstract: A method and system for fast link failover is disclosed. According to one embodiment, a method is provided in which a failure of a first link between a network element and an upstream portion of a communications network is detected, and a second link or group of links between the network element and a downstream portion of the communications network is responsively disabled to maintain a communications channel between the downstream and upstream portions of the communications network.