Abstract: Embodiments of the present invention route a wavelength division multiplexed signal across multiple communication paths using skew characteristics of at least some of the communication paths. The network is a wavelength division multiplexed optical transport network. The plurality of communication paths involves different signal and path attributes such as a plurality of carrier wavelengths, optical carrier groups, physical communication paths (different nodes, different fibers along a same path, or any combination of the foregoing), or any other differentiating factors between two paths.

Abstract: Embodiments of the present invention route a wavelength division multiplexed signal across multiple communication paths using skew characteristics of at least some of the communication paths. The network is a wavelength division multiplexed optical transport network. The plurality of communication paths involves different signal and path attributes such as a plurality of carrier wavelengths, optical carrier groups, physical communication paths (different nodes, different fibers along a same path, or any combination of the foregoing), or any other differentiating factors between two paths.

Abstract: Consistent with the present disclosure, a plurality of FIFO buffers, for example, are provided in a switch, which also includes a switch fabric. Each of the plurality of FIFOs is pre-filled with data for a duration based on a skew or time difference between the time that a data unit group is supplied to its corresponding FIFO and a reference time. The reference time is the time, for example, after a delay period has lapsed following the leading edge of a synch signal, the timing of which is a known system parameter and is used to trigger switching in the switch fabric. Typically, the delay period may be equal to the latency (often, another known system parameter) or length of time required for the data unit to propagate from an input circuit, such as a line card of the switch or another switch, to the FIFO that receives the data unit. At the reference time, temporally aligned data unit groups may be read or output from each FIFO and supplied to the switch fabric.

Abstract: A propagation delay in the transmission of a frame from an initiator node to a peer node is determined by initially identifying a frame number and byte offset of a first incoming frame from the peer node at a time when the initiator node outputs a portion of a transmitted frame. The portion of the transmitted frame may be the first byte of a sub-frame within the transmitted frame. At the peer node, the frame number and byte offset of a second frame to be supplied to the initiator node is identified at a later time when the frame portion transmitted by the initiator node is received by the peer node, and such information is transmitted to the initiator node. Thus, since the frames output and received by the initiator node are typically of fixed duration, the frame number and byte offset of the incoming frame represent the time when the initiator node outputs the frame portion (a transmit time).

Abstract: Consistent with the present disclosure, a communication system is provided in which client data is received and provided in frames for transmission within the system. The frames include an overhead portion as well as locations that include the client data. The frames further include phase data or “virtual justifications” that periodically correct the difference between the phase represented by the data locations in the wrapper and the actual accumulated client phase. The phase data or virtual justifications, however, are decoupled from the data path. Therefore, without complicating the data path, the phase data may be sent more frequently and with finer granularity than the actual justifications. Virtual justifications or phase data are communicated via a “virtual justification control channel” which may part of the frame overhead. Moreover, there is no need for an actual “virtual justification opportunity” in the frame, because no data is actually sent in conjunction with the virtual justifications.

Abstract: An optical device transmits ECC codewords using an interleaved technique in which a single ECC codeword is transmitted over multiple optical links. In one particular implementation, the device may include an ECC circuit configured to supply ECC codewords in series, the codewords being generated by the ECC circuit based on input data and each of the codewords including error correction information and a portion of the data. The device may further include a serial-to-parallel circuit configured to receive each of the codewords in succession, and supply data units in parallel, each of the data units including information from a corresponding one of the codewords; an interleaver circuit to receive the data units in parallel and output a second data units in parallel, each of the second data units including bits from different ones of the data units; and a number of output lines, each of which supplying a corresponding one of the second data units.

Abstract: A method, performed in a network that includes a group of nodes, includes identifying a path through a set of the nodes, where each node, in the set of nodes, has a data plane and a control plane; establishing a control plane tunnel, associated with the path, within the control plane of the nodes in the set of nodes; establishing a data plane tunnel, associated with the path, within the data plane of the nodes in the set of nodes, where the data plane tunnel is associated with the control plane tunnel and established through the same set of nodes; and transmitting a control message through the control plane tunnel to change a state of the data plane tunnel.

Abstract: A method includes receiving client data; extracting overhead data from the client data; mapping the client data into one or more frames, where each of the one or more frames has a frame payload section and a frame overhead section, where the client data is mapped into the frame payload section of the one or more frames; inserting the overhead data into the frame overhead section of the one or more frames; transporting the one or more frames across a network; extracting the overhead data from the frame overhead section of the one or more frames; recovering the client data from the one or more frames; inserting the extracted overhead data into the recovered client data to create modified client data; and outputting the modified client data.

Abstract: An optical transmission network is inherently asynchronous due to the utilization of a variable overhead ratio (V-OHR). The network architecture makes extensive use of OEO regeneration, i.e., deals with any electronic reconditioning to correct for transmission impairments, such as, for example, FEC encoding, decoding and re-encoding, signal reshaping, retiming as well as signal regeneration. The optical transmission network includes a plesiochronous clocking system with intermediate nodes designed to operate asynchronously with a single local frequency clock without complicated network synchronization schemes employing high cost clocking devices such as phase locked loop (PLL) control with crystal oscillators and other expensive system components.

Abstract: Embodiments of the present invention route a WDM signal across multiple communication paths using skew characteristics of at least some of the communication paths. The network is an optical transport network, using either circuit or packet based switching, and wavelength division multiplexed wavelengths and/or optical carrier groups (“OCGs”) over a fiber link to another node in the network. The plurality of communication paths involves different signal and path attributes such as a plurality of carrier wavelengths, optical carrier groups, physical communication paths (different nodes, different fibers along a same path, or any combination of the foregoing), or any other differentiating factors between two paths.

Abstract: The present invention provides a system, apparatus and method for accurately identifying optical or digital impairments on a span using FEC errors identified at an intermediary node. This information may be provided to an end node within a network to switch to a redundant path around the impaired optical path or span therein. In one embodiment of the invention, signal degradation is identified by analyzing FEC data within a FEC decoded signal at an intermediary node. An identification of signal degradation provides an indication of a potential failing span within an optical link, which may be provided in-band or out-of-band to a terminal node so that a signal may be switched around a failing path, or span therein, prior to an actual failure event.

Abstract: An optical transmission network is inherently asynchronous due to the utilization of a variable overhead ratio (V-OHR). The network architecture makes extensive use of OEO regeneration, i.e., deals with any electronic reconditioning to correct for transmission impairments, such as, for example, FEC encoding, decoding and re-encoding, signal reshaping, retiming as well as signal regeneration. The optical transmission network includes a plesiochronous clocking system with intermediate nodes designed to operate asynchronously with a single local frequency clock without complicated network synchronization schemes employing high cost clocking devices such as phase locked loop (PLL) control with crystal oscillators and other expensive system components.

Abstract: A network may include an ingress node that is configured to receive a client signal having a client rate that is one of a multiple different client rates, asynchronously map the client signal into a first frame of a first rate, asynchronously map the first frame into a second frame of a second rate, and output the second frame on the network; an intermediate node that is configured to receive the second frame, recover the first frame from the second frame, asynchronously map the first frame into a third frame of a third rate, and output the third frame on the network, where the intermediate node does not recover the client signal from the first frame; and an egress node that is configured to receive the third frame, recover the first frame from the third frame, recover the client signal from the first frame, and output the client signal.

Abstract: Embodiments of the present invention route a wavelength division multiplexed signal across multiple communication paths using skew characteristics of at least some of the communication paths. The network is a wavelength division multiplexed optical transport network. The plurality of communication paths involves different signal and path attributes such as a plurality of carrier wavelengths, optical carrier groups, physical communication paths (different nodes, different fibers along a same path, or any combination of the foregoing), or any other differentiating factors between two paths.

Abstract: A system, apparatus and method are described for controlling the gain across one or more amplifier nodes within an optical span. In one embodiment, a fast local amplifier constant gain control loop is provided that maintains a constant gain across an amplifier node for each of the channels within an optical signal. A slow link level gain setting control loop is provided to set and/or adjust the target gain on the amplifier node(s). A gain adjust sequence is performed by the slow link level gain setting control loop to adjust the target gain(s) in response to various events and mechanisms. A “time of flight” protection method is also provided to ensure consistency between the fast local amplifier gain control loop and the slow link level gain setting control loop.

Abstract: A network device may include a set of switches. Each of the switches may include a set of ingress links and a set of egress links. One of the switches may store mapping information that identifies a first timeslot and one of the egress links for data received, during a second timeslot, on one of the ingress links. The one of the switches may receive data, associated with the second timeslot, on the one of the ingress links, identify the first timeslot and the one of the egress links, associated with the second timeslot and the one of the ingress links, based on the mapping information, and output the data, during the first timeslot, on the one of the egress links.

Abstract: Embodiments of the present invention compensate for skew across a wavelength division multiplexed network. The network is a wavelength division multiplexed optical transport network. The skew compensation can be performed electrically or optically. It can be performed on the transmission side of the network, the receiver side of the network or at any intermediary node on the network.

Abstract: Embodiments of the present invention route a WDM signal across multiple communication paths using skew characteristics of at least some of the communication paths. The network is an optical transport network, using either circuit or packet based switching, and wavelength division multiplexed wavelengths and/or optical carrier groups (“OCGs”) over a fiber link to another node in the network. The plurality of communication paths involves different signal and path attributes such as a plurality of carrier wavelengths, optical carrier groups, physical communication paths (different nodes, different fibers along a same path, or any combination of the foregoing), or any other differentiating factors between two paths.

Abstract: Embodiments of the present invention determine skew relative to a plurality of communication paths on a network system. The network is a wavelength division multiplexed optical transport network. The plurality of communication paths involves different signal and path attributes such as a plurality of carrier wavelengths, optical carrier groups, physical communication paths (different nodes, different fibers along a same path, or any combination of the foregoing), or any other differentiating factors between two paths.

Abstract: An optical transmission network is inherently asynchronous due to the utilization of a variable overhead ratio (V-OHR). The network architecture makes extensive use of OEO regeneration, i.e., deals with any electronic reconditioning to correct for transmission impairments, such as, for example, FEC encoding, decoding and re-encoding, signal reshaping, retiming as well as signal regeneration. The optical transmission network includes a plesiochronous clocking system with intermediate nodes designed to operate asynchronously with a single local frequency clock without complicated network synchronization schemes employing high cost clocking devices such as phase locked loop (PLL) control with crystal oscillators and other expensive system components.