What is a system of connected private networks outside an organization's firewall using internet technology called?

The concept described in the question pertains to a system that allows secure communication and data sharing among various parties outside an organization’s firewall, utilizing internet technology. This system is known as an extranet. An extranet serves as a controlled extension of an organization’s internal network, enabling external users—such as partners, vendors, or customers—to access certain information or applications in a secure manner.

Using internet protocols and standards, an extranet effectively creates a bridge between the organization's private network and external entities while maintaining strict security controls. This secure connection allows for collaborative communication and integration with external stakeholders without compromising the overall security of the internal network.

In contrast, the other options do not fit this description. Architecture generally refers to the structured design or arrangement of components in systems and networks but does not specifically address the connectivity aspects highlighted in the question. EMPI (Enterprise Master Patient Index) is focused on accurately identifying patients across different healthcare organizations, which is unrelated to network systems. Ethernet is a networking technology used for local area networks (LANs) to facilitate communication and data exchange, but it does not describe the concept of connecting external users securely to an internal system.