An example method comprises receiving, by a first PHY of a first transceiver, a timing packet, timestamping, by the first transceiver, the timing packet and providing the timing packet to a first intermediate node, determining a first offset between the first intermediate node and the first transceiver, updating a first field within the timing packet with the first offset between the first intermediate node and the first transceiver, the offset being in the direction of the second transceiver, receiving the timing packet by a second transceiver, the timing packet including the first field, information within the first field being at least based on the first offset, determining a second offset between the second transceiver and an intermediate node that provided the timing packet to the second transceiver and correcting a time of the second transceiver based on the information within the first field and the second offset.

A method for synchronizing networks is disclosed. A first wired communication system having a first time base is set up in a first network. A second wired communication system having a second time base is set up in a second network. The first network and the second network are connected to a wireless communication system via a first translation unit and a second translation unit, respectively. The first translation unit and the second translation unit are synchronized to one another according to a third time base of the wireless communication system independently of the first time base and the second time base. A third synchronization message is transmitted from the first translation unit to the second translation unit. A transmission time for the third synchronization message in the third time base is determined and is used to synchronize the second time base to the first time base.

Time recovery techniques are described. A method comprises receiving messages from the first device by the second device in the first network domain, the messages to comprise time information to synchronize a first clock for the first device and a second clock for the second device to a network time, determining the second clock is to recover the network time for the second device without new messages from the first device, retrieving a first set of timestamps previously stored for events in the first network domain using the network time from the second clock, retrieving a second set of timestamps previously stored for the events in the first network domain using a redundant time from a third clock, where the third clock is not synchronized with the first and second clocks, and recovering the network time using a regression model and the redundant time from the third clock.

Techniques to secure a time sensitive network are described. An apparatus may establish a data stream between a first device and a second device in a network domain, the network domain includes a plurality of switching nodes, receive messages from the first device by the second device in the network domain, the messages to comprise time information to synchronize a first clock for the first device and a second clock for the second device to a network time for the network domain, update a correction field for a received message with a residence time and time delay value by the second device, determine whether the updated message is benign or malicious, update the correction field for the updated message with an inference time when the updated message is benign, and prevent relay of the updated message to other devices in the network domain when the updated message is malicious.

Time stamp replication within wireless networks is described. In an embodiment, a wireless station receives an input time stamp and uses this input time stamp to generate an output time stamp. The wireless station transmits the output time stamp to wireless stations in one of a number of groups which make up the wireless network. The output time stamp is generated to compensate for delays between receiving the input time stamp and transmitting the output time stamp such that output time stamp which is transmitted at a time T corresponds to the value that the input time stamp would have had if it had been received at time T (and not at a time earlier than T). This may, therefore, reduce or eliminate independent time stamp errors and jitter caused by multiple disparate systems and processes.

A synchronization information transmission method includes: receiving synchronization information sent by a preceding node; on the basis of synchronization accuracy information of a current node, updating intermediate node information in the synchronization information; and sending the updated synchronization information to a subsequent node.

A time synchronization mechanism is provided for reducing influences of link asymmetry between time synchronization devices. A second transmission device 2 includes: a transmission section 16 configured to transmit packets for delay calculation for a plurality of wavelengths to the corresponding time transmission device simultaneously; and a reception section 17 configured to calculate a propagation delay Dms on a path from the corresponding time transmission device to the second transmission device 2 based on a difference between the arrival times of the packets for delay calculation for the plurality of wavelengths received from the corresponding time transmission device, receive a propagation delay Dsm on a path from the second transmission device 2 to the corresponding time transmission device calculated by the corresponding time transmission device, and calculate a propagation delay Dmax that is larger than any of the propagation delay Dms and the propagation delay Dsm. The reception section 17 transmits a received PTP packet to a slave node 4 after waiting for a waiting delay Wms that is calculated by subtracting the propagation delay Dms from the propagation delay Dmax.

A shared bus time interleaves 1 PPS signal and control and coordination information between a primary timing source and line cards that need to be synchronized using the 1 PPS signals. The shared bus utilizes 1 second frames divided into time slots. The 1 PPS signals are interleaved at predetermined locations in the frame so the delays introduced by interleaving the 1 PPS data in time can be precisely removed. While the bus is not being used for 1 PPS signals, the bus is available to send control and coordination information between the line cards and the primary timing source, avoiding the use of another system and increasing utilization of an available communication path.

A method for synchronizing a timing end application (TEA) in an edge communication network includes (a) receiving, at a first access device, a time stamp from a first TEA communicatively coupled to the first access device, (b) transmitting the time stamp from the first access device to a second access device via communication media of the edge communication network, (c) adjusting the time stamp to account for transit time of the time stamp from the first access device to the second access device, and (d) after adjusting the time stamp, transmitting the time stamp from the second access device to a second TEA communicatively coupled to the second access device.

This disclosure describes methods and systems to for a method for a first computing node to receive frequency information of a system clock. The first computing node receives the frequency information of the system clock from a second computing node at a physical layer of a connection between the first computing node and the second computing node. The first computing node also receives a message from the second computing node at above the physical layer of the connection between the first computing node and the second computing node. The message includes an attestation of the frequency information from which the first computing node may verify that the second computing node is a trusted source of the frequency information.