...come from India, China and Iran. Of those that are physically in the US, very few have the minimum experience stated in the listing. A candidate located in the US with the correct experience and speaks English fluently is a rare find.
LinkedIn is good for networking but not much else with respect to recruiting candidates, IMO.
If you have a child still trying to decide upon a career path, let them know they will never want for employment if they choose infrastructure-related engineering.