Hello!
I am considering buying a dedicated time server for my network for the purpose of keeping everything precisely in sync. I may also be using it in the future for wireless sync that some other wireless protocols support. Something like this: http://www.spectracomcorp.com/Products/NetworkTimeServers/tabid/112/Default.aspx
Now, I would prefer to save the money and use the GPS sync and NTP server capability of the routerboard. However, I have some concerns about clock drift and the stability of these devices as a time source. One thing that a dedicated time server provides is the guarantee on crystal/oscillator tolerance and interrupt moderation to keep the timing tight.
I guess what I’m asking is if anyone has researched or tested these devices (routerboards) thoroughly for timing precision? I know that PC’s are notorious for having a lot of drift. Has anyone tested to see how much load the NTP server included with routeros can handle?
ive been using a gps on routeros for 2-3 years now. it doesnt play nice with windows all the time (stratum isn’t 0 or 1 or something). i am using it on x86 however. i believe the routeros gps sync is pretty good. however, using it on a routerboard wouldn’t be a good idea since it doesnt have a battery, and sometimes you might serve up time as 1/1/1980 (or whatever the intial date is) on a reboot.
It wouldn’t play nice with windows because it’s stratum is <= than the client. In other words, when a client makes an initial request, it’s stratum is 16 (usually). If the ntp daemon isn’t synced, it will set itself to stratum 16. Windows will error out with something like “Server stratum is not less than client”. I don’t remember the exact wording. But it’s something like that.
Thank you for your informative experience. I think it is somewhat disturbing that you are experiencing those issues (specifically it’s not syncing and setting itself to st 16), even on a very limited basis. I have another thought.. that is, how come RB’s don’t keep their time (consistently) through reboots? Is this a design/cost consideration (normis or uldis?)? How come a slot (or something) isn’t provided for us to just slip in a small battery? Not that this is a big deal. I can provide external ups. Just a question.
Another thought,
I have set up my gps to sync with the routerboard and am using some ntp analysis software to tell me more information about what I’m receiving from the ntp server. It states that I am on stratum 4 and do not have GPS as a reference clock. In fact, the reference is blank? Anyone from mikrotik willing to explain? Thanks!
Here are some further observations:
On startup (of gps module in routeros), ntp client will report stratum 1 and GPS reference. After about a minute, it rolls back to stratum 4 and then reports no reference. If I change the set-system-time option (yes or no) it will again report stratum 1, etc for a minute, then return to it’s (bad) behaviour.
im seeing this also on 3.25… i was seeing stratums lower than 4 at least on earlier versions, not sure where it went wrong. please email a supout and some details and lets get this fixed again.
The other problem is that the NTP server does not reply using the same source ip that the request came in on, so if you have multiple routes outbound it’s not very useful.
Hi Sam,
Can you please describe in detail what your setup is?
Mine goes like this (as far as the GPS signal):
GPS → Navman SE sleeve → IPAQ 3975 → GPSGate redirect into serial port → RB450G (3.25)
I think that this particular route is what is causing the huge timing issues for me, but it should still be stratum 1. Maybe the NTP server is picking up that I have a weird signal chain and degrading the stratum? It’s magic!
Mikrotik: Is it possible to have a bit more configuration options or more information displayed for the NTP server and GPS module? Namely, I’d like to be able to specify more than two time servers in the client (recommended minimum is 3) for reference (in case I’m not using GPS). Also, when the NTP module is not installed the NTP client page on winbox gives a LOT more information, which can be very useful. I would like this window to give more information such as the stratum, jitter, difference, etc.. and also be available when the NTP module is installed. I need more info! Can we please dialogue about this and the issues Sam and I are experiencing?
Thank you!
Mine is just a straight rs-232 gps module plugged directly into com1… I just think there wasn’t much effort put into the gps / ntp server packages… sad to say.
Yes. I have to say the results of my testing are pretty discouraging. The ntp server typically has over 200ms delay on a LAN.
Mikrotik! PLEASE tell me what’s up with this and what can I do?
Thanks!