The modern communication network is a system organically established by professional organizations with communication equipment (hardware) and related working procedures (software). It is the sum total of various communication services provided to individuals, enterprises, institutions and society. The Internet (Internet) is composed of multiple computer networks, transmission, exchange (here mainly refers to routers, switches, hubs), and terminals. It is the Internet all over the world.
Optical access/transport network
WLAN / PAN