Adva Optical Networking Se

Adtran Networks Se

Michael Rabinovich

Moshe Tofef

Andrew Sergeev

Joo Yeon Cho

Shihuan Zou

Igal Pinchasov

There is provided a technique of securing clock synchronization between master clock node (MCN) and client clock node (CCN). During a cycle of exchanging PTP messages between MCN and CCN, MCN generates an associated paired message for each PTP message generated thereby and informative of tor ttimestamps provided by MCN and sends each paired message to a validation entity (VE) via a secured channel between MCN and VE. When PTP messages traverse transparent clock nodes (TCN) between MCN and CCN, each TCN generates a paired message for each version of PTP message updated thereby and sends each generated paired message to VE via a secured channel between respective TCN and VE. VE uses the received paired messages to provide a validation of the cycle, wherein synchronization-related task(s) (e.g. clock correction by the client clock node, etc.) are provided only subject to successful validation of the cycle by VE.

Secured clock synchronization in a packet-compatible network

There is provided a method of clock recovery and a system thereof. The method comprises: by master clock node or by client clock node, generating a first flow of time-stamped packets bearing indication of high priority of delivery and, in parallel, generating a second flow of time-stamped packets bearing indication of lower priority of delivery. By client clock node, processing the packets from the first flow separately from the packets from the second flow to define, separately for each flow, a function informative of changes of packets' delays in the respective flow over time; using the defined functions informative of changes of packets' delays in the first and the second flows over the same time intervals to assess a cause of the packets' delays changes; and applying a clock recovery algorithm in a manner differentiated in accordance with the assessed cause.

System and method of clock recovery in a packet-compatible network

There is provided a technique of clock managing in a packet data network implementing a time-transfer protocol. The technique comprises: modifying, by the timing-server, a timestamp record to enable a controllable access to data informative of the least significant part of clock-informative data (CLSP data), wherein modifying the timestamp record comprises modifying the least significant part of the timestamp record (RLSP) to comprise the CLSP data in an encrypted form or to comprise values substituting, in a predefined manner, the CLSP data; transferring the modified timestamp record to all timing-clients, wherein CLSP data are transferred in a controllable access manner; enabling access to the CLSP data merely to authorized timing-clients among the plurality of timing-clients; and enabling the authorized timing-clients to obtain the CLSP data and synchronize the respective clocks using the CLSP data together with data informative of the most significant part of the clock-informative data.

System and method of synchronizing a distributed clock in a packet-compatible network

There is provided a technique of time delivery in a computing system comprising a system call interface (SCI) located in a kernel space and operatively connected to a time client located in a user space. The technique comprises: using a time agent component located in the user space to measure data indicative of delay in a system time delivery and to derive therefrom a system time delivery error TE; using TEto enable correction of system time; and sending by the SCI the corrected system time in response to a 'Read Clock RT' (RCRT) call received from the time client. The method can further comprise: measuring data indicative of delays in the system time delivery for RCRT calls with different priorities; and in response to a system time request received from the time client, providing the time client with system time corrected per TEcorresponding to the recognized priority thereof.

Method of time delivery in a computing system and system thereof

There is provided a method of clock management in a packet data network (PDN) implementing a time-transfer protocol and a clock controller configured to operate therein. The clock controller is configured to: obtain topology data informative of a master clock node and a slave clock node constituting end points of a PTP path in the PDN and further informative of at least part of transit nodes of said PTP path; periodically obtain data informative of queue size and link rate characterizing, during a collection period, the at least part of transit nodes in master-slave (MS) and slave-master (SM) directions; for each collection period, use the obtained queue-related data to estimate queue-induced delay asymmetry of the PTP path; and send the estimated value of queue-induced delay asymmetry to the slave node, the estimated value to be used by a clock residing on the slave node as delay asymmetry correction parameter.

System and method of clock management in a packet data network

There are provided a clock node, a controller, a method of operating the clock node and a method of operating the controller in a time distribution network (TDN) comprising the controller being in data communication with the clock nodes via a control path. The method of operating the clock node comprises: sending, from the clock node via the control path to the controller, a first timestamp-related data; receiving, by the clock node via the control path from the controller, clock-recovery control data generated by the controller using the first timestamp-related data received from the clock node; processing the received clock-recovery control data to extract data usable for phase and frequency recovery; and using the extracted data to steer frequency and phase characterizing the clock node.

A method for assessing the performance of packet synchronization services in a packet data transmission network. The method includes, at a packet data transmission network probing point, determining at least two synchronization quality describing or influencing parameters based on at least one of a digital timing signal (Sp) received, the recovered time information for at least one timing parameter transmitted into the packet data transmission network, and parameters having impact on the synchronization quality and describing or controlling properties of hardware components present at a receiving network node. The method also includes, at the packet data transmission network probing point, determining a value of at least one synchronization performance score based on the at least two synchronization quality describing or influencing parameters.

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Modiin, Israel

Michael Rabinovich