Wide area network

Short description: Computer network that connects devices across a large distance and area

A local area network (LAN) with connection to a wide area network (WAN) Computer network types
by spatial scope

* Nanoscale
* Near-field (NFC)
* Body (BAN)
* Personal (PAN)
* Near-me (NAN)
* Local (LAN)
* Home (HAN)
* Storage (SAN)
* Wireless (WLAN)
* Campus (CAN)
* Backbone
* Metropolitan (MAN)
* Municipal wireless (MWN)
* Wide (WAN)
* Cloud (IAN)
* Internet
* Interplanetary Internet

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A wide area network (WAN) is a telecommunications network that extends over a large geographic area. Wide area networks are often established with leased telecommunication circuits.[1]

Businesses, as well as schools and government entities, use wide area networks to relay data to staff, students, clients, buyers and suppliers from various locations around the world. In essence, this mode of telecommunication allows a business to effectively carry out its daily function regardless of location. The Internet may be considered a WAN.[2] Many WANs are, however, built for one particular organization and are private. WANs can be separated from local area networks (LANs) in that the latter refers to physically proximal networks.

## Contents

* 1 Design options
* 2 Private networks
* 3 Connection technology
* 4 See also
* 5 References
* 6 External links

## Design options

The textbook definition of a WAN is a computer network spanning regions, countries, or even the world.[3][4] However, in terms of the application of communication protocols and concepts, it may be best to view WANs as computer networking technologies used to transmit data over long distances, and between different networks. This distinction stems from the fact that common local area network (LAN) technologies operating at lower layers of the OSI model (such as the forms of Ethernet or Wi-Fi) are often designed for physically proximal networks, and thus cannot transmit data over tens, hundreds, or even thousands of miles or kilometres.

WANs are used to connect LANs and other types of networks together so that users and computers in one location can communicate with users and computers in other locations. Many WANs are built for one particular organization and are private. Others, built by Internet service providers, provide connections from an organization's LAN to the Internet.

WANs are often built using leased lines. At each end of the leased line, a router connects the LAN on one side with a second router within the LAN on the other. Because leased lines can be very expensive, instead of using leased lines, WANs can also be built using less costly circuit switching or packet switching methods. Network protocols including TCP/IP deliver transport and addressing functions. Protocols including Packet over SONET/SDH, Multiprotocol Label Switching (MPLS), Asynchronous Transfer Mode (ATM) and Frame Relay are often used by service providers to deliver the links that are used in WANs. It is also possible to build a WAN with Ethernet.[5]

Academic research into wide area networks can be broken down into three areas: mathematical models, network emulation, and network simulation.

Performance improvements are sometimes delivered via wide area file services or WAN optimization.

## Private networks

Of the approximately four billion addresses defined in IPv4, about 18 million addresses in three ranges are reserved for use in private networks. Packets addressed in these ranges are not routable on the public Internet; they are ignored by all public routers. Therefore, private hosts cannot directly communicate with public networks, but require network address translation at a routing gateway for this purpose. <section begin=IPv4-private-networks/>

Reserved private IPv4 network ranges[6] Name | CIDR block | Address range | Number of addresses | Obsolete classful description

|
|
|
|

24-bit block | 10.0.0.0/8 | 10.0.0.0 – 10.255.255.255 | 16777216 | Single Class A.
20-bit block | 172.16.0.0/12 | 172.16.0.0 – 172.31.255.255 | 1048576 | Contiguous range of 16 Class B blocks.
16-bit block | 192.168.0.0/16 | 192.168.0.0 – 192.168.255.255 | 65536 | Contiguous range of 256 Class C blocks.
<section end=IPv4-private-networks/>

Since two private networks, e.g., two branch offices, cannot directly communicate via the public Internet, the two networks must be bridged across the Internet via a virtual private network (VPN) or other form of IP tunnel that encapsulates packets, including their headers containing the private addresses, for transmission across the public network. Additionally, encapsulated packets may be encrypted to secure their data.

## Connection technology

Many technologies are available for wide area network links. Examples include circuit-switched telephone lines, radio wave transmission, and optical fiber. New developments have successively increased transmission rates. In c. 1960, a 110 bit/s line was normal on the edge of the WAN, while core links of 56 or 64 kbit/s were considered fast. Today, households are connected to the Internet with dial-up, asymmetric digital subscriber line (ADSL), cable, WiMAX, cellular network or fiber. The speeds that people can currently use range from 28.8 kbit/s through a 28K modem over a telephone connection to speeds as high as 100 Gbit/s using 100 Gigabit Ethernet.

The following communication and networking technologies have been used to implement WANs.

* Asynchronous Transfer Mode
* Cable modem
* Cellular networks[7]
* Dial-up internet
* Digital subscriber line
* Fiber-optic communication
* Frame Relay
* ISDN
* Leased line
* SD-WAN
* Synchronous optical networking
* Very small aperture terminal (VSAT)[7]
* Wi-Fi[7]
* WiMAX[7]
* X.25

AT&T conducted trials in 2017 for business use of 400-gigabit Ethernet.[8] Researchers Robert Maher, Alex Alvarado, Domaniç Lavery, and Polina Bayvel of University College London were able to increase networking speeds to 1.125 terabits per second.[9] Christos Santis, graduate student Scott Steger, Amnon Yariv, Martin and Eileen Summerfield developed a new laser that potentially quadruples transfer speeds with fiber optics.[10]

## See also

* Cell relay
* Internet area network (IAN)
* Label switching
* Low-power wide-area network (LPWAN)
* Wide area application services
* Wireless WAN

## References

1. ↑ Mitchell, Bradley. "What Is a Wide Area Network (WAN)?". Lifewire. https://www.lifewire.com/wide-area-network-816383.
2. ↑ Groth, David; Skandler, Toby (2005). Network+ Study Guide, Fourth Edition. Sybex, Inc. ISBN 0-7821-4406-3.
3. ↑ Forouzan, Behrouz (2012-02-17). Data Communications and Networking. McGraw-Hill. pp. 14. ISBN 978-0-07-337622-6.
4. ↑ Zhang, Yan; Ansari, Nirwan; Wu, Mingquan; Yu, Heather (2011-10-13). "On Wide Area Network Optimization". IEEE Communications Surveys & Tutorials 14 (4): 1090–1113. doi:10.1109/SURV.2011.092311.00071. ISSN 1553-877X.
5. ↑ CCNA Data Center DCICN 640-911 Official Cert Guide. Cisco Press. 14 November 2014. ISBN 978-0-13-378782-5. https://books.google.com/books?id=qLtoBQAAQBAJ&dq=wan+technology&pg=PT173.
6. ↑ Y. Rekhter; B. Moskowitz; D. Karrenberg; G. J. de Groot; E. Lear (February 1996), Address Allocation for Private Internets, Network Working Group IETF, doi:10.17487/RFC1918, BCP 5. RFC 1918, https://tools.ietf.org/html/rfc1918
7. ↑ 7.0 7.1 7.2 7.3 "Selecting a WAN Technology (1.2) > WAN Concepts | Cisco Press". https://www.ciscopress.com/articles/article.asp?p=2832405&seqNum=5.
8. ↑ "AT&T Completes Industry-Leading 400 Gb Ethernet Testing, Establishing A Future Network Blueprint for Service Providers and Businesses". September 8, 2017. http://about.att.com/story/att_completes_industry_leading_ethernet_testing.html.
9. ↑ Maher, Robert; Alvarado, Alex; Lavery, Domaniç; Bayvel, Polina (11 February 2016). "Increasing the information rates of optical communications via coded modulation: a study of transceiver performance". Scientific Reports 6 (1). doi:10.1038/srep21278. PMID 26864633. Bibcode: 2016NatSR...621278M.
10. ↑ "A New Laser for a Faster Internet - Caltech". Cal Tech. 19 February 2014. https://www.caltech.edu/news/new-laser-faster-internet-42090.

## External links

* Cisco - Introduction to WAN Technologies
* (in en-US) What is WAN?, https://www.techtarget.com/searchnetworking/definition/WAN-wide-area-network, retrieved 2025-10-30
* What is a software-defined wide area network?

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Telecommunications

History|

* Beacon
* Broadcasting
* Cable protection system
* Cable TV
* Communications satellite
* Computer network
* Data compression
* audio
* DCT
* image
* video
* Digital media
* Internet video
* online video platform
* social media
* streaming
* Drums
* Edholm's law
* Electrical telegraph
* Fax
* Heliographs
* Hydraulic telegraph
* Information Age
* Information revolution
* Internet
* Mass media
* Mobile phone
* Smartphone
* Optical telecommunication
* Optical telegraphy
* Pager
* Photophone
* Prepaid mobile phone
* Radio
* Radiotelephone
* Satellite communications
* Semaphore
* Semiconductor
* device
* MOSFET
* transistor
* Smoke signals
* Telecommunications history
* Telautograph
* Telegraphy
* Teleprinter (teletype)
* Telephone
* The Telephone Cases
* Television
* digital
* streaming
* Undersea telegraph line
* Videotelephony
* Whistled language
* Wireless revolution

Pioneers|

* Nasir Ahmed
* Edwin Howard Armstrong
* Mohamed M. Atalla
* John Logie Baird
* Paul Baran
* John Bardeen
* Alexander Graham Bell
* Tim Berners-Lee
* Jagadish Chandra Bose
* Walter Houser Brattain
* Vint Cerf
* Claude Chappe
* Yogen Dalal
* Donald Davies
* Lee de Forest
* Philo Farnsworth
* Reginald Fessenden
* Elisha Gray
* Oliver Heaviside
* Erna Schneider Hoover
* Harold Hopkins
* Internet pioneers
* Bob Kahn
* Dawon Kahng
* Charles K. Kao
* Narinder Singh Kapany
* Hedy Lamarr
* Innocenzo Manzetti
* Guglielmo Marconi
* Robert Metcalfe
* Antonio Meucci
* Jun-ichi Nishizawa
* Radia Perlman
* Alexander Stepanovich Popov
* Johann Philipp Reis
* Claude Shannon
* Henry Sutton
* Nikola Tesla
* Camille Tissot
* Alfred Vail
* Charles Wheatstone
* Vladimir K. Zworykin

Transmission
media|

* Coaxial cable
* Fiber-optic communication
* optical fiber
* Free-space optical communication
* Molecular communication
* Radio waves
* wireless
* Transmission line
* data transmission circuit
* telecommunication circuit

Network topology
and switching|

* Bandwidth
* Links
* Nodes
* terminal
* Network switching (circuit
* packet)
* Telephone exchange

Multiplexing|

* Space-division
* Frequency-division
* Time-division
* Polarization-division
* Orbital angular-momentum
* Code-division

Networks|

* ARPANET
* BITNET
* Cellular network
* Computer
* CYCLADES
* Ethernet
* FidoNet
* Internet
* Internet2
* ISDN
* LAN
* Mobile
* NGN
* NPL network
* Public Switched Telephone
* Radio
* Telecommunications equipment
* Television
* Telex
* WAN
* Wireless network
* World Wide Web

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