Simple Network Time Protocol - Avaya 4524GT Configuration Manual

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Simple Network Time Protocol

The Simple Network Time Protocol (SNTP) is a subset of the Network Time Protocol. It provides
a simple mechanism for time synchronization.
Clocks use NTP to synchronize to a few milliseconds, depending on the clock source and local
clock hardware.
SNTP synchronizes the Universal Coordinated Time (UTC) to accuracy within 1 second.
This feature adheres to the RFC 2030 (MIB is the s5agent). With this feature, the system can
obtain the time from any RFC 2030-compliant NTP or SNTP server.
The SNTP feature allows you to set an offset from GMT for the time zone of your location. You
can also set a start date and end date and offset for Daylight Savings Time.
The SNTP client implementation for this feature is unicast. The SNTP client operates typically
in a unicast mode but can use the broadcast and multicast modes.
SNTP accuracy is typically in the order of significant fractions of a second. This accuracy
correlates to the latencies between the SNTP client device and the NTP server. In a low-latency
network, the SNTP accuracy can be reduced to less than a 100 millisecond range and, to
further increase the accuracy, you can use a simple latency measurement algorithm.
The intended accuracy for this implementation is 1 second, which is sufficient for logs and time
displays on UIs.
When SNTP is enabled (the default value is Disabled), the system synchronizes with the
configured NTP server at boot-up (after network connectivity is established) and at user-
configurable periods thereafter (the default synchronization interval is 24 hours). The
synchronization also can happen upon manual request.
The SNTP feature supports both primary and secondary NTP servers. It attempts to contact
the secondary NTP server only if the primary NTP server is unresponsive. When a server
connection fails, SNTP retries for a maximum of three times, with 5 minutes between each
retry.
54 Configuration — System April 2011