[ntp:questions] Motorola Canopy CMM as NTP server
dimss at telecentrs.lv
Fri Sep 29 09:35:38 UTC 2006
Motorola Canopy is wireless networking system. Up to six Canopy
sector access points (AP) can be used together as cluster
managed by CMM (Cluster Management Module). CMM contains GPS
receiver which is used to synchronize multiple transmitters. CMM
has IP address and NTP server running on port 123. The server
reports itself as Stratum-1.
Some people use CMM as primary time source of their networks. I
have tried this too. But my ntpd quickly "disqualified"
those "Stratum-1" units and reverted to Stratum-2 servers! ntpq
showed that CMM units had unacceptable jitter values (hundreds
Packet sniffer showed that Canopy CMM always reports time
rounded to integer number of seconds. This is the problem. CMM
has very accurate GPS time inside it but reports only seconds
through NTP. I am unsure is it bug or "feature".
I have requested feedback from Motorola. For now, do not use
Canopy CMM as NTP server for anything but Canopy equipment.
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