topic Re: time synchronization problem in Switches, Hubs, and Modems

time synchronization problem

Hommer_1 — Fri, 02 Dec 2005 09:11:27 GMT

Hi,
here in short my problem:

Topology:
-Core Router 3400CL 6VLANS (Number 0-5)
-inside each VLAN 2-3 Switches Procurve Type 2524 or 2824
- existing Windows Time Server in VLAN 0

Situation:
Time is correct on all Switches in VLAN0
an on the core router

Problem:
I am not able to synchronize time on
all other switches in VLAN 1-5

What can I do? What's going wrong?

THX
rudolf

Re: time synchronization problem

Ardon — Fri, 02 Dec 2005 13:57:31 GMT

Hommer,

First of all,and that is all I can say right now based on the info you supply, do these switches have connectivity to the Time Server. Can you ping it from these switches?

Regards, Ardon

Re: time synchronization problem

Les Ligetfalvy — Fri, 02 Dec 2005 16:12:52 GMT

Since they are in another VLAN, I assume they reach the time server by route. Did you set the timesync on the switches to use unicast or broadcast? Broadcast won't cross routers.

Re: time synchronization problem

Hommer_1 — Mon, 05 Dec 2005 04:30:16 GMT

Thanks for the answers, they helped me to find out what was going wrong. Expecially the information that it should work with unicast.

The back-route from the time server was not set correctly - so now it works, but:

So that's o.k. but:
Some switches show the correct time, some others show a time 2hrs earlier. With the same time settimg:

Time Sync Method [None] : SNTP
SNTP Mode [Disabled] : Unicast
Server Address : 10.130.10.13
Poll Interval (sec) [720] : 720
Server Version [3] : 3
Time Zone [0] : 60
Daylight Time Rule [None] : Western-Europe

This seems strange.

THX
rudolf

Re: time synchronization problem

Thomas Bianco — Mon, 05 Dec 2005 11:22:55 GMT

the windows time service is really optimized to talk to other windows time services. consider using a full port of NTP.

http://ntp.isc.org/bin/view/Main/ExternalTimeRelatedLinks#Microsoft_Windows

bear in mind any NTP service will require at least a rough synchronization before it can start correcting the time. a co-worker's watch sync is all that's required to get close enough (generally within one minute) for NTP to take over.