Abstract: A physical layer communication device (PHY) transmits and receives signal to and from a communication link using a synchronous protocol. The PHY communicates with a higher-layer device using a packet protocol. Timestamp values contained in timing-related messages in some packets are written or modified by the PHY. Delays incurred in transmitting and receiving the packets are predicted and used in setting the timestamp values.

Abstract: A transparent clock converter is interposed between a non-precision time protocol (non-PTP) enabled network node and other portions of the network. The transparent clock converter effectively converts the non-PTP node into a transparent clock node. In some embodiments the transparent clock converter includes physical layer devices, but not media access controllers.

Abstract: Precision Timing Protocol (PTP) related functions for use in packet communications carried in part by a microwave communications link include setting of time of day values across the microwave link and providing transparent clock functions. The PTP functions may be used for synchronizing radio base stations in a cellular network. The transparent clock can bridge Ethernet switches associated with microwave stations providing the microwave communications link.

Abstract: A physical layer device provides both timestamp processing and security processing. The timestamp processing may be PTP processing according to IEEE Std. 1588 and/or OAM processing according to ITU-T Recommendation Y.1731. The security processing may be MACsec processing according to IEEE Std. 802.1AE. The timestamp processing may delay some packets to avoid impairing accuracy of timing information. For example, the accuracy of timing information could be impaired when a packet containing the timing information is delay due to additional bits added to a preceding packet to include a security tag and integrity check value.

Abstract: A system and method for measuring a propagation delay in a point to multipoint network. The system includes a central timing module which provides a timing signal to a plurality of line cards. Each of the line cards includes a local clock that is frequency locked to a 1588 clock and is configured to generate a return timing signal to the central timing module after a predetermined number of clock cycles. The central timing module measures the propagation delay based on the clock cycles of the local clock counted before the return signal is generated and the period of the local clock.

Abstract: Continuously interleaved codewords are used in a communication system to provide error correction capability. In general, each codeword shares symbols with both preceding and subsequent codewords, when the codewords are arranged in an order, such that correction of symbols in any one codeword also corrects symbols in another codeword and correction of symbols in any codeword may allow, considering possible corrections of intermediate codewords, for further correction of any codeword in the order of codewords. In one embodiment received information may be arranged in subframes, with each subframe including terminal symbols of a plurality of codewords, each of the plurality of codewords including symbols in multiple subframes.

Abstract: Methods and devices generate cyclic redundancy check (CRC) values for a sequence of parallel words of data. The data words may have only some of the bits enabled. The input words are preconditioned, and then a common block generates a CRC remainder value. A specific preconditioning is selected based on the number of enabled bits. Additional post-processing may be performed to the CRC remainder.

Abstract: A physical layer device provides security processing on communication frames that may include tags or headers that are for use in a wide area network. As frames pass through the physical layer device, the frames are classified for a type of security processing. Depending on the classification a cipher is applied to the frames for integrity checking of data in the frames. Some frames are also encrypted. The security processing may exclude some of the tags or headers. The frames may also be filtered and buffered.