A typical enterprise-level network is segregated into multiple security zones or “rings”:
Ring 1: The Internet Edge
Ring 2: The Backbone Edge
Ring 3: The Asset Network Edge
Ring 4: Local Host Security
These zones are a logical way to group the firewall’s physical and virtual interfaces, and control traffic. Traffic can flow freely within a zone, but not between different zones until you define and allow it within the firewall policy configuration. In general, more zones means a more secure network