Describe the IBM Cloud Object Storage System™ NTP functions

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The Network Time Protocol (NTP) is a standard protocol for synchronizing clocks between interconnected computer systems. It is used ubiquitously from notebooks to desktop computers to production servers.

NTP uses UDP port 123. The software and associated documentation are available at NTP: The Network Time Protocol (http://www.ntp.org/).

In a system, it is assumed that all nodes contain synchronized clocks. The clocks are accurate to within 1 second across the various nodes; however, small clock variations do not pose any functional issues. System clocks can be synchronized to an external time source. Clocks require access to the internet or to an NTP server on the customer’s private network. When neither is available, the clocks can still be synchronized to each other, but are inaccurate when compared to the real time.

The following terms are used:

synchronize

In the NTP model:

The NTP daemon is properly communicating with the remote clock.
The local clock characteristics are identified.

It does not necessarily mean that the times on the two clocks match. Two clocks that are synchronized might still have a significant offset, but the system corrects itself over time. It does not mean that the two clocks have the same exact time.

delay

Measured round-trip time for network communication from the local NTP daemon to the remote clock.

offset

Calculated difference between the local clock and the remote clock is measured in units of time (typically seconds).

jitter

The apparent variation in the remote clock from the perspective of the local clock.

Note: For example, the local clock believes 60 seconds passed while the remote clock indicates 59 seconds passed, but then in a different 60-second period, the remote clock indicates that 61 seconds passed.

drifting

The slow, small adjustments (about one or 2 seconds per hour) that the NTP daemon makes to the local clock to match the remote clock. The daemon adjusts the local clock over a long period so no large gaps in the clock time are perceived by locally running system processes.