Internal networks are split into logical segments so that they can be isolated and separated. Initially, these segments were introduced to contain and limit network traffic and to save bandwidth. Now, segmented networks serve as additional elements in a comprehensive security architecture. Additional Firewalls can be introduced between network segments.
As a case in point, a financial accounting department’s network might be tightly controlled and not even be accessible from other internal locations. Should one of the internal systems be compromised by crackers, the intruder would face additional barriers before he or she could brag about “0wning” the complete network or having access to the “crown jewels.”