Horrible ntp offset time

[Odys (CSC)]

Good day everybody,

Due to the horrible offset time at the access switches, the sync procces takes days sometimes weeks to update.

Any idea what's going on ?

- the ntp server is the destribution switch me3800x. It listens to ntp clients (the access switches) on its private ip address 172.31.13.1. And its ntp master is a public time source.

- the sntp clients are the access switches sg300/200 (only sntp is available). And their management ip addresses are directly connected to the 172.31.13.1 (in the same subnet)

- outputs show the high offset:

show sntp status

-----------------------------------------------

Server : 172.31.13.1
Source : Static
Stratum : 3
Status : up
Last Response : 15:32:36.0 DST Aug 7 2019
Offset : 1294312.6839201 mSec
Delay : 0 mSec

----------------------------------------------

Server : 172.31.13.1
Source : Static
Stratum : 3
Status : up
Last Response : 14:58:10.0 CET Aug 7 2019
Offset : 182105659000 mSec
Delay : 0 mSec

------------------------------------------

Server : 172.31.13.1
Source : Static
Stratum : 3
Status : up
Last Response : 14:08:31.0 DST Aug 12 2019
Offset : -166208.4489413 mSec
Delay : 0 mSec

------------------------------------------------

[marce1000]

 Hmm, it is difficult to comment on because it may be a 'configuration bug' somewhere which is cloaked from or in your post. But more fundamental I don't like these setups. I advise a none-switch node as NTP server (service) on the Intranet which syncs with a perimeter NTP server (e.g.) which then chains or uses NTP services from the Internet. That's how we do it. I advice to not use a switch for master NTP server so to keep NTP and networking services separated.

  M.

[Odys (CSC)]

The ME3800 (ntp server) is a L3 switch with routing enabled.

It's syncing to a healthy ntp master. Here is the output of show ntp status:

Clock is synchronized, stratum 3, reference is 194.109.6.2
nominal freq is 250.0000 Hz, actual freq is 249.9952 Hz, precision is 2**8
ntp uptime is 1531930400 (1/100 of seconds), resolution is 4016
reference time is E15AEE2B.C2C02064 (17:20:11.760 CEST Wed Oct 23 2019)
clock offset is 0.3190 msec, root delay is 1.37 msec
root dispersion is 45.04 msec, peer dispersion is 3.96 msec
loopfilter state is 'CTRL' (Normal Controlled Loop), drift is 0.000018965 s/s
system poll interval is 1024, last update was 773 sec ago.