All companies that have been pwned by APT (advanced persistent threat) adversaries look for ways to fend off future threats. Often, their plans include creating highly secure “crown jewel” networks. Most companies want to create one or more separate, additional networks. The idea is that the crown jewel assets should be protected at a much higher level. For maximum security, you can always go Pentagon-style, with physically separate air-gapped networks that don’t connect to the Internet.”]
Source: https://www.csoonline.com/article/2611573/should-you-create-a-separate–supersecure-network-.html