From: Shawn David Solomon <sdsolomo@iupui.edu> I'm glad we've wandered upon the topic of stratum 1 clocks. I've been looking for a clock that has the capability to provide clocking to Cisco ATM switches (BPX's) and also provide a clock source for our unix hosts. Do they make such a beast? is it a good idea to use the clock for both purposes? Actually, you're looking for two different things here: 1) a frequency standard that is traceable to a cesium or rubidium frequency source, with an output of 1 MHz, 10 MHz, 100 MHz, or whatever the PLL in the Cisco wants to see to discipline the line clocking, and 2) a time standard (synchronized to USNO) with a 1PPS output that is synchronized to the top of the second. My question would be, what is the goal here? All of the integrated plug-n-play NTP servers represent a tradeoff of money for time, but that may well represent a wise choice if you don't have someone on your staff who has built a stratum 1 NTP server before. If there is some reason to use the same clock for both? If not, there is a pretty good chance that you can set up two separate units, a GPS-based unit for the computers and a Cs or Rb standard for the ATM switch for less money than you would pay for a brand new integrated unit. This is particularly true if you're handy with surplus shops -- I have seen Rb standards going for as low as $800 (working, with plenty of life left in the tube), and if you have plenty of time and access to an already-calibrated frequency standard, even the calibration is well within the capabilities of any reasonably advanced technical generalist. If you want to talk more about this, let's take it offline before someone sends me email telling me that NTP is not an operational issue (bah!). :) ---rob PS: links o' the day (bouquet of options from ready-made to roll-your-own): http://www.truetime.com/DOCS/request.html http://www.tmo.hp.com/tmo/Summaries/English/#Frequency_Time_Standards_and_Sy... http://www.trimble.com/oem/om_timng.htm http://www.mot.com/AECS/PNSB/products/pnsbprod.html http://www.tapr.org/tapr/html/tac2.html