A baseline difference is determined between a slave line card time stamp corresponding to a slave line card frame sync signal and a master line card time stamp corresponding to a master line card frame sync signal. The slave line card generates subsequent slave line card time stamps for subsequent slave line card frame sync signals and the master line card generates subsequent master line card time stamps for subsequent master line card frame sync signals. Current differences are determined between subsequent slave line card time stamps and the subsequent master line card time stamps and the current differences are compared to the baseline difference. When a mismatch difference occurs (current difference differs from the baseline difference), the mismatch difference causes a phase-locked loop in the master line card to be adjusted or an offset to be provided to the master line card time of day counter.

A baseline difference is determined between a slave line card time stamp corresponding to a slave line card frame sync signal and a master line card time stamp corresponding to a master line card frame sync signal. The slave line card generates subsequent slave line card time stamps for subsequent slave line card frame sync signals and the master line card generates subsequent master line card time stamps for subsequent master line card frame sync signals. Current differences are determined between subsequent slave line card time stamps and the subsequent master line card time stamps and the current differences are compared to the baseline difference. When a mismatch difference occurs (current difference differs from the baseline difference), the mismatch difference causes a phase-locked loop in the master line card to be adjusted or an offset to be provided to the master line card time of day counter.

Techniques for facilitating a robust clock synchronization across a computer network that presumes network jitter exists are discussed herein. A first device and a second device transceive a plurality of sets of time-synchronization messages to synchronize a synchronization clock of the second device to a first clock of the first device. The second device calculates a smoothing of time delay data of a plurality of sets. The time delay data is associated with a transmission duration of time-synchronization messages of the sets of the plurality. The second device sets a synchronization clock based on a time at the first device and the smoothed time delay data.

A communication system and a communication method for one-way transmission are provided. The communication method includes: receiving, by a precision time protocol switch, a first synchronization message from a grandmaster clock; generating, by the precision time protocol switch, a second synchronization message according to the first synchronization message; transmitting, by the precision time protocol switch, the second synchronization message to a transmitting server and a programmable logic device; generating, by the transmitting server, a timestamp according to the second synchronization message; transmitting, by the transmitting server, at least one data packet and the timestamp to the precision time protocol switch; forwarding, by the precision time protocol switch, the at least one data packet and the timestamp to the programmable logic device; and determining, by the programmable logic device, whether to output the at least one data packet according to the timestamp and the second synchronization message.

A network device such as a router or switch, in one embodiment, includes a timing analyzer which is capable of providing timing analysis over one or more network circuits. The timing analyzer, in one aspect, receives a data packet traveling across a circuit emulation service (“CES”) circuit such as T1 or E1 circuit. Upon obtaining an arrival timestamp associated with the data packet, the arrival timestamp is stored in a timestamp buffer in accordance with a first-in first-out (“FIFO”) storage sequence. After identifying the oldest arrival timestamp in the timestamp buffer, an offset is generated based on the result of comparison between the arrival timestamp and the oldest timestamp. The timing analyzer can also be configured to generate timing reports on-demand based on generated offset(s).

Embodiments of the present application disclose a data transmission method, device, and system, and belong to the field of communications technologies. The method includes: receiving and temporarily storing, by a first node device, a designated service group sent by a second node device; and when the first node device needs to forward multiple SAToP or CESoPSN service packets in the temporarily stored designated service group, determining, by the first node device, whether an asynchronous SAToP or CESoPSN service packet exists in the designated service group, and if yes, acquiring, by the first node device, an adjustment value for the asynchronous SAToP or CESoPSN service packet according to a preset rule, and adjusting the asynchronous SAToP or CESoPSN service packet according to the adjustment value, so that the multiple SAToP or CESoPSN service packets in the designated service group are transmitted synchronously.

The disclosure describes methods and systems for performing time synchronization in a heterogeneous system. In one example, a method includes evaluating, by a computing system, one or more network conditions of a network to determine whether to perform a time synchronization process with a secondary device in the network, wherein the one or more network conditions include a health score for the secondary device, and, in response to determining, based on the evaluation of the one or more network conditions, to perform the time synchronization process: determining based at least in part on a time indication for a clock on a master device and a time indication for a clock on the secondary device, a time synchronization offset for the secondary device; and sending the time synchronization offset for the secondary device to the secondary device in a data packet.

In various embodiments, a method is provided. In this method, a first signal is received from a master node, and is sampled to obtain a first sample. The first sample is then quantized to obtain a quantized form of the first sample. A first synchronization sequence is detected from the quantized form of the first sample at T2. First information is received from the master node and the first information is used to indicate a moment T1 at which the master node sends the first synchronization sequence. A second synchronization sequence is sent to the master node at T3. Second information received from the master node and the second information is used to indicate a moment T4 at which the master node detects a quantized form of the second synchronization sequence. Time synchronization is performed based on T1, T2, T3, and T4.

The present disclosure provides systems and methods for proving an event. The system comprises a network of one or more beacon nodes and each beacon node is configured to: receive a request over the network for proving a time and location for an event, and the request comprises event data generated by a requesting entity; create a timestamp for the event using a clock of the beacon node, wherein the clock is synchronized to a trusted time source; generate a hash code for the timestamp and the event data and record the hash code to a ledger at the beacon node.

The disclosure describes methods and systems for performing time synchronization in a heterogeneous system. In one example, a method includes, for each secondary device of a plurality of secondary devices in a network: determining, by a computing system and based at least in part on a time indication for a clock on a master device and a time indication for a clock on a secondary device in the network, a time synchronization offset for the respective secondary device; collecting, from the respective secondary device, one or more static parameters and one or more dynamic parameters; determining, based on the one or more parameters, a weight to associate with the time synchronization offset for the respective secondary device; determining, based on each of the respective time synchronization offset for each of the plurality of secondary devices and the respective associated weight, a universal time synchronization offset for the network.