Enterprise Data Center Topology
Source: Cisco Systems
A typical large enterprise network often consists of multiple data centers, each with a responsibility for supporting key functions. In general, these data centers can be classified into three types: Internet, extranet and Intranet. The Internet data center, which is used by external clients connecting from the Internet, supports the servers and devices required for business-to-consumer transaction-based web applications (e-commerce). The extranet data center provides support and services for external, Business-to-Business (B2B) partner transactions. These services are often accessed over secure VPN connections or private WAN links between the partner network and the enterprise extranet.