I’ve tested the server into two different environments: LAN and WAN. I confirm the relatively small capacity of the Soekris to support 200-300 units connected to it for NTP UDP as ideal load without alter performances.Of course the major limits comes with Ethernet , T1 and line speed. We could never get nanoseconds over there at least for now. So the happy part was to see the offset slowly stabilize (20 hours ca) around +/- 120 ns with peaks of 10 ns even less remaining stable over those numbers, with a frequency error of -0.038 PPM and fixed jitter of 0.015
(the offset should be the difference between the system clock and PPS , the frequency error instead of -0.038 PPM should be the frequency offset of 0.333..(X) Hz from the integer value that the FreeBSD kernel utilize in its computations.)
This , for comparison, was the frequency offset of a x64 server using the GPS 1PPS from its serial :
Of course all this was wasted as soon UDP packets travels along just the local area network under a WiFi connection :
Anyway I’ve done some stress tests on WAN, through the NTP global address pool with a static IP address and a bandwidth of 1Mbit/s connecting more than 3000 units to the 4501 as stratum 1 (!) : Los Angeles often dropped the board from the pool , but the Soekris earn some good points with this huge load of traffic over a normal ADSL as you see from the ntp.pool monitor graph :
Delta² 