9 LTOS7 Management and Monitoring
Submenu Cluster:
The Cluster mode is a method for providing redundant time synchronization by groupping (clustering) multiple
LANTIME NTP servers. Within this group, the participating NTP servers continuously exchange status and
quality information with each other. The status information is compared among each other and by a special
algorithm a decision is made, which of the NTP servers should act as a current MASTER in the network. The
rest of the group acts as SLAVE and stays passive as a backup. If the current master loses its synchronization
source or any other failure occurs, another NTP server from the cluster takes over the master role. The current
master responds to requests from NTP clients via a common cluster IP. Even if the master is replaced by another
NTP server, this IP does not change.
The configuration of a NTP cluster is useful if at the side of NTP clients only one IP address for an ex-
ternal NTP server can be configured and redundancy is still required.
The current master is selected according to the following parameters in this order:
1. NTP status (sync, not sync);
2. Priority (configurable by the user, the lowest value has the highest priority, default = 0);
3. Ref-Clock Type - GNSS receivers such as GPS have the highest rating;
4. Ref-Clock Status (sync, not sync).
LANTIME CPU Expansion Shelf
Date: 2nd July 2020
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Summary of Contents for LCES
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