Hi Nick, Last year I have designed an NTP server with sub-microsecond turnaround accuracy/jitter at fully saturated 100K+ packets/sec traffic (full 100Mb wire speed) that costs just £250 from stock. Its holdover performance on signal loss is in the order of 4-5ms/day. https://store.uputronics.com/index.php?route=product/product&path=60_70&product_id=92
If you can come up with a cheaper and higher performance alternative I am very interested in licensing your design. When you come to testing I can highly recommend placing your prototypes in public NTP pool and asking the admins to add it to .ch zone - you are guaranteed to get full 110kpps traffic spikes that will help to flush out bugs. Just a few devices collectively served 1.1 trillion packets in less than a year http://leobodnar.com/LeoNTP/ (and have been through the infamous snapchat incident.) Jitter and holdover need to be tested on a controlled LAN segment - I can highly recommend contacting Denny Page on this list and sending him a unit to test. He built sophisticated and highly tuned testing system that tracks timing jitter and offset down to dozens of nanoseconds accuracy. Denny is vendor-neutral and provided honest and fair feedback while I was developing my unit. Hope this helps! Thanks Leo On 26 Oct 2017, at 17:00, [email protected] wrote: > Date: Wed, 25 Oct 2017 17:53:46 -0700 > From: Nick Sayer <[email protected]> > > I’ve just completed a project (off topic) with the ATSAMS70 chip and learned > a lot in a relatively short time, and I really like the result. > > I am considering a new project based on its cousin, the ATSAME70. The E70 has > an Ethernet 10/100 MAC built in as well as the rest of the stuff the S70 has > (USARTs, SD/MMC, AES-256, TRNG, high-speed USB… it’s quite nice), and Atmel > Start (the software development framework I’ve been using) purports to have a > ready-to-use IP stack (alas, no IPv6, but it’s a starting point at least). > > Where I am going with this is I am considering designing a precision embedded > NTP/PTP server. I’d connect one of the SkyTraq modules I’ve got piles of up > to a GPIO and USART and the Ethernet port would provide NTP/PTP. The idea > behind making it an embedded system would be to try and make it as accurate > as it reasonably can be with the hope that (at least on the local segment) it > would wind up being more accurate than a Pi Zero doing the same thing. At the > very least, you’d expect such a thing to be a whole lot less hassle to set > up, given decent firmware. > > This may be a fool’s errand, certainly, but looking at it from here, I would > think that such a design might offer accuracy in the microsecond range, but > that’s just a tremendously uninformed guess at this point (and what does that > accuracy mean to a peer that might itself be incapable of better than 2 > orders of magnitude coarser?). > > Anybody have any ideas or suggestions along these lines? _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
