Cisco Internetworking Design Guide
Internetworkingthe communication between two or more networksencompasses every aspect of connecting computers together. Internetworks have grown to support vastly disparate end-system communication requirements
An internetwork requires many protocols and features to permit scalability and manageability without constant manual intervention. Large internetworks can consist of the following three distinct components: Campus networks, which consist of locally connected users in a building or group of buildings Wide-area networks (WANs), which connect campuses together Remote connections, which link branch offices and single users (mobile users and/or telecommuters) to a local campus or the Internet. This design guide applies to each aspect of networking.