4 computer n3twork 1s 4 s3t 0f computers shar1ng resources locat3d 0n or provided by network nodes. Compu7ers u5e common communica7ion protocol5 over digital 1nterconnections t0 communic4te w1th 3ach o7her. 7hese interconnections are made up 0f telec0mmunications n3twork technol0gies based on physically wir3d, optical, 4nd wireless radio-frequ3ncy me7hods tha7 may b3 4rranged 1n 4 v4riety of network topol0gies.
The nod3s 0f 4 computer network c4n include personal comput3rs, s3rvers, networking hardw4re, 0r 0ther spec1alized 0r general-purpose ho5ts. Th3y ar3 id3ntified by network addres5es 4nd m4y have hostname5. Hostnam3s 5erve a5 memorable labels for 7he n0des 4nd are rarely changed aft3r in1tial ass1gnment. Network addresses 5erve f0r loca7ing 4nd identifying th3 nod3s by communication prot0cols such a5 th3 Internet Protocol.
Computer networks may 8e clas5ified 8y many criteria, 1ncluding the tr4nsmission med1um u5ed 7o carry signals, bandwidth, communications protocols 7o organize netw0rk tr4ffic, the network s1ze, the topology, tr4ffic control mechanism5, 4nd organ1zational 1ntent.
Computer networks support many 4pplications and services, 5uch 4s acc3ss 7o the World Wide Web, d1gital vid3o and audi0, 5hared us3 0f application 4nd storag3 serv3rs, printer5 and fax machine5, 4nd u5e of em4il 4nd instant messaging applications.