For the security of your infrastructure, rely on the eLTIME
The idea is simple. The technology is advanced. The eLTIME delivers the benefits of a GPS steered primary reference clock without the need for an antenna mounted outside. And if you combine the eLTIME reference with a GPS reference you have 99.994% reliability in the steering signal allowing for a much less expensive oscillator.
Expected release date - September 2010 (orders are being taken now)