D-Link DGS-3630 User Manual 1 - Page 44

DGS-3630 Series Layer 3 Stackable Managed Switch Web UI Reference Guide Parameter From Time ~ To Time Description Select the starting and ending time of the day that will be used for this time profile. The first drop-down menu selects the hour and the second drop-down menu selects the minute. Click the Apply button to accept the changes made. Click the Find button to locate a specific entry based on the information entered. Click the Delete Periodic button to delete the periodic entry. Click the Delete button to delete the specified entry. PTP (Precise Time Protocol) The Precision Time Protocol (PTP) system is able to synchronize the distributed clocks with an accuracy of less than 1 microsecond via Ethernet networks. PTP is a technology that enables precise synchronization of clocks in network systems. PTP is applicable to systems communicating by Local Area Networks supporting multicast messaging including Ethernet and UDP. PTP enables heterogeneous systems that include clocks of various inherent precision, resolution and stability to synchronize to a grandmaster clock. The synchronization is divided into two processes. The Best Master Clock (BMC) algorithm determines the PTP status (master/slave) of all local ports. The synchronization algorithm computes the clock offset between the master and slave clock. There are two mechanisms, Delay Request-response Mechanism and Peer Delay Mechanism, for measuring the propagation time of an event message. The PTP system has three types of PTP devices, boundary clock, end-to-end transparent clock, and peer-to-peer transparent clock. Only the boundary clock can participate in the selection of the best master clock. When the stacking mode is enabled and the member ports of a trunk group exists in different stack units, the PTP function will: • Execute normally when the sending and receiving of PTP messages are to member ports that are on the same stack unit. • Execute abnormally, when the sending and receiving of PTP messages are to member ports that are on different stack units. PTP Global Settings This window is used to display and configure the global Precise Time Protocol (PTP) settings. 32