Your organization has broken its network into several sections/segments, which are separated by firewalls, ACLs...

Your organization has broken its network into several sections/segments, which are separated by firewalls, ACLs and VLANs. The purpose is to defend segments of the network from potential attacks that originate in a different segment or that attempt to spread across segments.

This style of defense-in-depth protection is best described as which of the following?