Computer networking

Such networks involve at least two devices capable of being networked with at least one usually being a computer. The devices can be separated by a few meters (e.g. via Bluetooth) or thousands of kilometers (e.g. via the Internet). Computer networking is sometimes considered a sub-discipline of telecommunications.

History
Carrying instructions between calculation machines and early computers was done by human users. In September 1940 George Stibitz used a teletype machine to send instructions for a problem set from his Model K at Dartmouth College in New Hampshire to his Complex Number Calculator in New York and received results back by the same means. Linking output systems like teletypes to computers was an interest at the Advanced Research Projects Agency (ARPA) when, in 1962, J.C.R. Licklider was hired and developed a working group he called the "Intergalactic Network", a precursor to the ARPANet. In 1964, researchers at Dartmouth developed the Dartmouth Time Sharing System for distributed users of large computer systems. The same year, at MIT, a research group supported by General Electric and Bell Labs used a computer (DEC's PDP-8) to route and manage telephone connections. Throughout 1960s Leonard Kleinrock, Paul Baran and Donald Davies had independently conceptualized and developed network systems consisting of datagrams or packets that could be used in a packet switching network between computer systems. In 1969 the University of California at Los Angeles, SRI (in Stanford), University of California at Santa Barbara, and the University of Utah were connected as the beginning of the ARPANet network using 50 kbit/s circuits.

Networks, and the technologies needed to connect and communicate through and between them, continue to drive computer hardware, software, and peripherals industries. This expansion is mirrored by growth in the numbers and types of users of networks from researcher

Categorizing

By network layer
See the seven layer OSI reference model and the four or five layer TCP/IP model

Application layer
Presentation layer (Only in the OSI model)
Session layer (Only in the OSI model)
Transport layer
Network layer
Data Link layer
Media access control sublayer
Logical link control sublayer
Physical layer

By scale
Personal area network (PAN)
Local area network (LAN)
Wireless local area network(WLAN)
Campus area network (CAN)
Metropolitan area network (MAN)
Wide area network (WAN)

By connection method
HomePNA
Power line communication
Ethernet
WiFi

By functional relationship
Active Networking (Low-level code movement versus static data)
Client-server
Peer-to-peer (Workgroup)

By network topology
Bus network
Star network
Ring network
Mesh network
Star-bus network
Tree topology network

By Services provided
Storage area networks
Server farms
Process control networks
Value-added network
SOHO network
Wireless community network
XML appliance
Jungle Networks

Protocol stacks
Computer networks may be implemented using a variety of protocol stack architectures, computer buses or combinations of media and protocol layers, incorporating one or more of:

ARCNET
AppleTalk
ATM
Bluetooth
DECnet
Ethernet
FDDI
Frame relay
HIPPI
IEEE 1394 aka FireWire, iLink
IEEE 802.11 aka Wireless LAN (Wi-Fi certification)
IEEE-488
TCP/IP protocol suite
IPX
Myrinet
QsNet
RS-232
SPX
System Network Architecture
Token ring
TCP
TCP Tuning for discussion of improving performance of same
USB
UDP
X.25 protocol suite
For a list of more see Network protocols.

For standards see IEEE 802.

Suggested topics
Further reading for acquiring an in-depth understanding of computer networks include:

Communication theory

Data transmission

Wired transmission
Public switched telephone network
Modems and dialup
Dedicated lines – leased lines
ISDN
DSL
Time-division multiplexing(TDM)
Packet switching
Frame relay
PDH
Ethernet
RS-232
RS-485
Optical fiber transmission
Synchronous optical networking(SONET)
Fiber distributed data interface

Wireless transmission
Extreme Short range
ZigBee
Short range
Bluetooth
InfraRed(IrDA)
Medium range
WiFi(IEEE 802.11)
WiMax(IEEE 802.16)
Long range
Satellite
MMDS
SMDS
Mobile phone data transmission (channel access methods)
CDMA
CDPD
GSM
TDMA
Paging networks
DataTAC
Mobitex
Motient