Principal components: nodes, links, protocols, switching equipment, transmission media.
There are several types of networks, including local area networks (LANs), metropolitan area networks (MANs), and personal area networks (PANs). Other types of networks include wide area networks (WANs), wireless LANs (WLANs), storage area networks (SANs), virtual private networks (VPNs), and campus area networks (CANs).