D: Network Time Protocol (Ntp); Leap Indicator; Editing Ntp.conf - Symmetricom XLi User Manual

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D: Network Time Protocol (NTP)

As an option, Symmetricom can factory configure the XLi to function as a Stratum 1 network time server.
Network time servers use Network Time Protocol (NTP) to synchronize computer clocks across a
network.
Support for version 4.0 of the NTP, RFC 1305 as well as the Simple Network Time Protocol (SNTP),
RFC2030 is available. In addition, the XLi responds to TIME protocol requests, RFC868.
The Network Time Server responds to time synchronization requests from hosts using these User
Datagram Protocol/Internet Protocols (UDP/IP):
Type/Protocol
NTP ver. 4.0:
SNTP:
TIME:
NTP Packet Transmitted Timestamp Accuracy ±10 milliseconds

Leap Indicator

After the XLi has entered a holdover state ("flywheeling" on its internal oscillator or Aux Ref while a time
reference is absent) for "n" hours, the Leap Indicator transitions to "11" and the Stratum Level stays at
"1". "n" is dependent upon the XLi reference oscillator. When an internal phase error within the NTP
server is greater than 1 millisecond the Leap Indicator will transition to unsynchronized ("11"). This can
take a very long time when an OCXO or Rb is installed in the XLi.
XLi Operational State Stratum LI
Power ON 1
GPS Locked 1
GPS Unlocked 1
GPS Unlocked (after n 1
hours)*
* n is dependent upon the XLi reference oscillator

Editing ntp.conf

Note:
The XLi is a Stratum 1 NTP server. Therefore, it does not support NTP peering, in which a time
server gets time information by sending an NTP query to another time server. Entering valid IP
addresses for the 'server' parameters (e.g., "
enable peering in the XLi.
The current text of "ntp.conf" is as follows:
XLi Time & Frequency System
XLi-man, Issue 8, 6/17/2008, Rev. H
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
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Port Number
UDP Port 123
UDP Port 123
UDP Port 37
11
00
00
11
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RFC
RFC1305
RFC2030
RFC868
server 216.210.169.40
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2
1
5
") in ntp.conf does not
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