A method of frame synchronization comprises receiving a stream of bits, the stream comprising a sequence of frames, wherein each frame comprises a frame counter value representing the number of the frame in the sequence, and frame check bits for checking the validity of the frame counter value. The method comprises decoding a first section of bits, and trailing a first portion of the first section of bits as a trial counter value, and a second portion of the first section of bits as trial check bits. The method comprises checking if the trial counter value corresponds to a valid frame counter value using the trial check bits, and synchronizing based on whether the trial counter value is determined to correspond to a valid frame counter value.

In one exemplary embodiment, a method includes: inserting an indication of a cyclic prefix length into a transmission; and sending the transmission. In another exemplary embodiment, a method includes: receiving a transmission; and processing the received transmission to obtain an indication of a cyclic prefix length.

A method for transmitting a client signal in an optical transport network includes: dividing a payload of an optical payload unit signal into m first-granularity tributary slots; dividing one of the m first-granularity tributary slots into n second-granularity tributary slots, where a rate of the first-granularity tributary slot is n times that of the second-granularity tributary slot, m is a positive integer, and n is a positive integer greater than 1; mapping a first client signal onto a payload in which one or more of the n second-granularity tributary slots are located; adding an overhead of the first-granularity tributary slot and an overhead of the second-granularity tributary slot for the optical payload unit signal, to generate an optical data unit signal; and sending the optical data unit signal.

In one exemplary embodiment, a method includes: inserting an indication of a cyclic prefix length into a transmission; and sending the transmission. In another exemplary embodiment, a method includes: receiving a transmission; and processing the received transmission to obtain an indication of a cyclic prefix length.

A cross connect apparatus or system with transparent clocking, consistent with embodiments described herein, connects a selected source or ingress port to a selected destination or egress port and clocks data out of the selected egress port using a synthesized clock that is adjusted to match a recovered clock from the selected ingress port. A transparent clocking system may generate the synthesized clock signal with adjustments in response to a parts per million (PPM) rate detected for the associated recovered clock signal provided by the selected ingress port. The cross connect system with transparent clocking may be a 400G cross connect system with 10G resolution. The cross connect system with transparent clocking may be used in optical transport network (OTN) applications, for example, to provide an aggregator and/or an add-drop multiplexer (ADM) or to provide a reconfigurable optical add-drop multiplexer (ROADM) upgrade to a higher data rate.

The present disclosure relates to data processing methods and apparatus. One example method includes obtaining a first data block, where the first data block is a data block obtained by dividing first optical path data, adding clock simplified padding data and the first data block into a target information bit in a first data frame to form target data, where the target information bit is an information bit that is preset in the first data frame and that is used to pad optical path data, encoding the target data by using a first error correction encoding scheme to obtain a first code block that has a mapping relationship with the first data frame, where the first error correction encoding scheme matches a frame structure of the first data frame, and sending the first code block.

A method of frame synchronization comprises receiving a stream of bits, the stream comprising a sequence of frames, wherein each frame comprises a frame counter value representing the number of the frame in the sequence, and frame check bits for checking the validity of the frame counter value. The method comprises decoding a first section of bits, and trailing a first portion of the first section of bits as a trial counter value, and a second portion of the first section of bits as trial check bits. The method comprises checking if the trial counter value corresponds to a valid frame counter value using the trial check bits, and synchronizing based on whether the trial counter value is determined to correspond to a valid frame counter value.

A cross connect apparatus or system with transparent clocking, consistent with embodiments described herein, connects a selected source or ingress port to a selected destination or egress port and clocks data out of the selected egress port using a synthesized clock that is adjusted to match a recovered clock from the selected ingress port. A transparent clocking system may generate the synthesized clock signal with adjustments in response to a parts per million (PPM) rate detected for the associated recovered clock signal provided by the selected ingress port. The cross connect system with transparent clocking may be a 400G cross connect system with 10G resolution. The cross connect system with transparent clocking may be used in optical transport network (OTN) applications, for example, to provide an aggregator and/or an add-drop multiplexer (ADM) or to provide a reconfigurable optical add-drop multiplexer (ROADM) upgrade to a higher data rate.

Embodiments of the present disclosure provide a data transmission method and a device, and the method includes: determining synchronization header indication information indicating a frame header location of a first code stream, where the first code stream is obtained by encoding CPRI service data; decoding the first code stream to obtain a second code stream, where the first code stream is a 10B code stream, and the second code stream is an 8B code stream, or the first code stream is a 66B code stream, and the second code stream is a 64B code stream; inserting frame header indication information indicating a frame header location of the second code stream into the second code stream according to the synchronization header indication information; and mapping the second code stream and the frame header indication information into an OPU in an ODU frame.

Systems and methods for Physical Coding Sublayer (PCS) encryption implemented by a first network element communicatively coupled to a second network element include encrypting a Flexible Ethernet (FlexE) signal based on a first encryption key with encryption applied to a 64b/66b bit stream associated with the FlexE signal at one or more of a FlexE client layer and a FlexE shim layer; switching to a second encryption key at a predetermined point in the FlexE signal; and encrypting the FlexE signal with the second encryption key subsequent to the switching.