Computer networking is the engineering discipline concerned with communication between computer systems or devices. Networking, routers, routing protocols, and networking over the public Internet have their specifications defined in documents called RFCs.

A computer network is any set of computers or devices connected to each other with the ability to exchange data

local area network (LAN)
wide area network (WAN)
wireless LANs and WANs (WLAN & WWAN)

All networks are interconnected to allow communication with a variety of different kinds of media, including twisted-pair copper wire cable, coaxial cable, optical fiber, and various wireless technologies

Network topology
The network topology defines the way in which computers, printers, and other devices are connected, physically and logically. A network topology describes the layout of the wire and devices as well as the paths used by data transmissions. Commonly used topologies include:

Bus , Star , Tree (hierarchical) , Linear , Ring , Mesh , partially connected ,
fully connected (sometimes known as fully redundant) ,

Cables , Entertainment Network, Firewallls, Home networking,  Hubs, Interface Cards Pci, Load balancing,  Mainframes,  Print servers, Racks & Mounts, OS Software,  Servers,  Storage NAS SAN,  Telephones, Terminals/Workstations, UPS ,  Voip, Video Conferencing,  Wireless Routers, Wired Routers.