Standalone Time source

[LawnBoy]

I'm looking to create my own stratum 1 timesource for NTP. I have a small process control network that must remain isolated from any external connection, and I envision loading Fedora or SuSE on an older desktop pc to stand as an NTP source for the rest of the network.

Any suggestions as to what time receivers work well with linux? Either GPS or WWV would be acceptable, but I cannot hook this network to the internet in any way.

 

[jkupski]

Once upon a time, I worked for the Industrial Automation divison of Siemens, and our process control system offered a dedicated time source for situations like yours.

Talk to your vendor and see if they have something similar. It will be more expensive than the solution you're looking at (which is basically free) but it will support more than just NTP aware devices--it will likely support all of the devices on the network that your vendor sold you like PLCs, etc.

Just a thought.

 

[LawnBoy]

So far I've found a couple of boxes similar to what you suggest (EndRun and Symmetricom) but the cost is around $3500 (and I have a budget of, wait for it, zero dollars).

I actually need to serve time to 4 isolated networks and linux with iptables is the only way I can conceive of doing it.

Thanks for the tip.

 

[jkupski]

I understand completely. I have had alot of "zero budget" projects like that, myself. Best of luck to you!

There are lots of little mouse GPS units out there with serial interfaces that might be what you're looking for. In general you can find them for less than $50, and RS232 = no worrying about linux compatibility.

 

[LawnBoy]

It's amazing what you can figure out when you actually read your protocol specs...

NTP includes a provision for using a dialup as a secondary source should your receiver fail. No receiver = failed receiver; I'll just use a modem to dial NIST in Boulder Colorado. Problem solved, no money spent (phone bills don't come out of my budget <grin>).

 

[jkupski]

Sounds like a great solution, and I'll have to keep that one in mind.