Is a system designed to detect intrusion – unauthorized entry – into a building or other area.

Is the hardware and software resources of an entire network that enable network connectivity, communication, operations and management of an enterprise network. It provides the communication path and services between users, processes, applications, services and external networks/the internet.

Provide various functionalities, often called "services", such as sharing data or resources among multiple clients, or performing computation for a client.

Is an organization's strategy and provisions for ensuring the security of its assets and all network traffic. Network security is manifested in an implementation of security hardware and software.