Time synchronization for network testing equipment
AssigneeJDS Uniphase Corporation
InventorsCanning HSUEH, Michael STEVENS, Bob SAMWAY
Life of this patent
Estimating the term…
Abstract
The invention relates to time synchronization between network testing elements in distributed network monitoring and testing systems, and provides a condensed PTP process wherein the number of timing messages exchanged between master and slave in one iteration of the time synchronization process is reduced. Furthermore, timing messages are encrypted to provide for a more secure synchronization process. One aspect of the method provides for an automatic detection and adaptive handling of protocol stacks of received timing packets.
Claims16
A method for time synchronization between a master device and a slave device in a network, comprising:
- a) sending by the master device a Sync message (SyncM) to the slave device, and recording a time instant of Sync message transmission T1;
- b) recording by the slave device a time instant of SyncM reception T2;
- c) sending by the slave device to the master device a Delay request message (Del_ReqM) at a time instant T3, and recording T3 in memory;
- d) recording by the master device a time instance of Del_ReqM reception T4;
- e) sending by the master device a Follow up Delay response message (FDelRespM) comprising T4 and T1 to the slave device;
- and,
- f) computing a slave clock offset ‘O’ based on T1, T2, T3, and T4.
A method for time synchronization between a master device and a plurality of slave devices spaced in a network monitoring system, comprising:
- a) sending by the master device a Sync message to each of the slave devices, and recording a time instant T1 when the Sync message leaves the master device, and time instances T2 when each of the slave devices receives the Sync message;
- b) sending by each of the slave devices to the master device a Delay request (Del_Req) message, and recording time instances T3 at which the Del_Req messages leave the slave devices, and time instances T4 at which the Del_Req messages are received by the master device;
- c) communicating values of T4 and T1 to the respective slave devices;
- d) computing at each of the slave devices a slave device clock offset ‘O’ and a network time delay ‘D’ based on T1, T2, T3, and T4;
- e) communicating to the master device the network time delays D computed at each of the slave devices;
- and,
- f) outputting one or more of the network time delays D in association with network location identifiers for respective one or more slave devices and the master device to a user of the network monitoring system as network latency values.
Dependencies are inferred from the claim text.