Systems including at least one processor and a memory storing instructions that, when executed by the at least one processor, result in the system collecting real-time telemetry measurements for packets received at each hop of an overlay network, and the system injecting the measurements into a variable-length trailers of the packets.

A packet processing method includes receiving a first packet by a first receiving interface of a media conversion module of a first network device, where the first packet includes a first alignment marker (AM), sending a second packet by a first sending interface of the media conversion module, where the second packet includes the first AM, and where the second packet is the first packet processed by the media conversion module, and calculating a time interval T.sub.1 between a time at which the media conversion module receives the first packet and a time at which the media conversion module sends the second packet, where the T.sub.1 is used to compensate for a first timestamp at which the first network device receives or sends the third packet.

A network device includes one or more ports for connecting to a communication network, packet processing circuitry and clock circuitry. The packet processing circuitry is configured to communicate packets over the communication network via the ports. The clock circuitry includes a hardware clock configured to indicate a network time used for synchronizing network devices in the communication network, and a built-in accuracy test circuit configured to check an accuracy of the hardware clock.

A first signal generated from a signal generator may be synchronized with a local clock of a first device at a first time, and sent to a second device, the first signal having a first frequency. A second signal generated from the signal generator may be further synchronized with the local clock of the first device at a second time, the second signal having a second frequency different from the first frequency, and a difference between the second time and the first time being within a predetermined range of a predetermined time difference. The second signal may then be sent to the second device to enable the second device to determine a distance between the first device and the second device based at least in part on a phase difference between the first signal and the second signal.

The precision time protocol (PTP) runs on the peer switches in an MLAG domain. PTP messages received by one peer switch on an MLAG interface is selectively peer-forwarded to the other peer switch on the same MLAG interface in order to coordinate a synchronization session with a PTP node. The peer-forwarded messages inform one peer switch to be an active peer and the other peer switch to be an inactive peer so that timestamped messages during the synchronization session are exchanged only between the PTP node and the active peer, and hence take the same data path.

A system includes a plurality of line cards and a timing card. A clock generation circuit on the timing card generates a clock signal which is pulse width modulated according to information to be transmitted. A clock line supplies the pulse width modulated clock signal to the line cards. The timing card sends a first control word to the plurality of line cards over the clock line after sending a beacon. The first control word includes a size field specifying a first length of first data following the first control word. The timing card sends time of day information over the clock line to the line cards following the first control word. The time of day information may be encrypted. A second control word follows the time of day information. One or more additional control words can follow the second control word before the next beacon.

The present disclosure provides a method and apparatus for acquiring a timestamp of a data stream, a storage medium and an electronic apparatus. The method for acquiring the timestamp of the data stream includes: receiving a data stream to be transmitted, and acquiring a first frame header identifier of the data stream to be transmitted in a serializer-deserializer (SERDES) clock mode, the first frame header identifier being used for representing a position of a frame header of the data stream to be transmitted; determining, based on the first frame header identifier, a timestamp of the data stream to be transmitted under a system clock; encapsulating the timestamp to obtain a first target data frame; and outputting the first target data frame.

A network adapter includes a network port for communicating with a communication network, a hardware clock, and circuitry. The circuitry is coupled to receive from the communication network, via the network port, one or more time-protocol packets that convey a network time used for synchronizing network devices in the communication network, to align the hardware clock to the network time conveyed in the time-protocol packets, and to make the network time available to one or more time-service consumers running in a host served by the network adapter.

An example system comprising a first transceiver configured to receive a request airframe from a second transceiver over a wireless link, the request airframe including a first time indication indicating a first time TS1, a second time indication indicating a second time TS2 that the request airframe was received, generate a respond airframe and including a third time indication indicating a third time TS3 that the respond airframe is transmitted to the second transceiver, transmit the respond airframe to the second transceiver, provide a timestamp information request to second transceiver, receive a timestamp information response, the timestamp information response including a fourth time indication indicating a fourth time TS4, calculate a counter offset using the first time, second time, third time and fourth time as follows:

[00001]$\mathrm{counter}\mathrm{offset}=\frac{\left(\mathrm{TS}1+\mathrm{TS}4-\mathrm{TS}3-\mathrm{TS}2\right)}{2},$

calculate a phase offset based on the counter offset, and correct a phase of the first transceiver.

The present technology relates to a transmission apparatus, a transmission method, a reception apparatus, and a reception method that enable channel selection information and time information to be transmitted effectively. A transmission apparatus acquires channel selection information for selecting a service and time information used for synchronizations on a transmission side and a reception side, generates, as a physical layer frame constituted of a preamble and a data portion, the physical layer frame in which specific information including at least one of the channel selection information and the time information is arranged at a head of the data portion right after the preamble, and transmits the physical layer frame as digital broadcast signals. The present technology is applicable to IP packet broadcasting, for example.