Edge Rewrite
pun Source code View original
Jump to content

Wide area network

From Wikipedia, the free encyclopedia

A local area network (LAN) with connection to a wide area network (WAN)

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 functions 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.

Design options

[edit]

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

[edit]

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.

Reserved private IPv4 network ranges[6]
NameCIDR blockAddress rangeNumber of addressesObsolete classful description
24-bit block10.0.0.0/810.0.0.0 – 10.255.255.25516777216Single Class A.
20-bit block172.16.0.0/12172.16.0.0 – 172.31.255.2551048576Contiguous range of 16 Class B blocks.
16-bit block192.168.0.0/16192.168.0.0 – 192.168.255.25565536Contiguous range of 256 Class C blocks.

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

[edit]

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.

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]

Low-power wide-area networks

[edit]
This section is an excerpt from Low-power wide-area network § Platforms and technologies.[edit]

Some competing standards and vendors for LPWAN space include:[11]

  • DASH7, a low latency, bi-directional firmware standard that operates over multiple LPWAN radio technologies including LoRa.
  • Wize is an open and royalty-free standard for LPWAN derived from the European Standard Wireless Mbus.[12]
  • Chirp spread spectrum (CSS) based devices.
  • Sigfox, UNB-based technology and French company.[13]
  • LoRa is a proprietary, chirp spread spectrum radio modulation technology for LPWAN used by LoRaWAN, Haystack Technologies, and Symphony Link.[14][15]
  • mioty, implementing Telegram Splitting technology.
  • Weightless is an open standard, narrowband technology for LPWAN used by Ubiik
  • ELTRES, a LPWA technology developed by Sony, with transmission ranges of over 100 km while moving at speeds of 100 km/h.[16]
  • IEEE 802.11ah, also known as Wi-Fi HaLow, is a low-power, wide-area implementation of 802.11 wireless networking standard using sub-gig frequencies.[17]

See also

[edit]

References

[edit]
  1. ↑ Mitchell, Bradley. "What Is a Wide Area Network (WAN)?". Lifewire. Archived from the original on 2018-06-12. Retrieved 2017-04-21.
  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. p. 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. CiteSeerX 10.1.1.459.4653. doi:10.1109/SURV.2011.092311.00071. ISSN 1553-877X. S2CID 18060. {{cite journal}}: Cite uses deprecated parameter |citeseerx= (help)
  5. ↑ CCNA Data Center DCICN 640-911 Official Cert Guide. Cisco Press. 14 November 2014. ISBN 978-0-13-378782-5.
  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.
  7. 1 2 3 4 "Selecting a WAN Technology (1.2) > WAN Concepts | Cisco Press".
  8. ↑ "AT&T Completes Industry-Leading 400 Gb Ethernet Testing, Establishing A Future Network Blueprint for Service Providers and Businesses". www.att.com. September 8, 2017. Archived from the original on January 5, 2022. Retrieved August 20, 2018.
  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) 21278. Bibcode:2016NatSR...621278M. doi:10.1038/srep21278. PMC 4750034. PMID 26864633.
  10. ↑ "A New Laser for a Faster Internet - Caltech". Cal Tech. 19 February 2014. Archived from the original on 2017-05-11. Retrieved 2017-02-05.
  11. ↑ Sanchez-Iborra, Ramon; Cano, Maria-Dolores (2016). "State of the Art in LP-WAN Solutions for Industrial IoT Services". Sensors. 16 (5): 708. Bibcode:2016Senso..16..708S. doi:10.3390/s16050708. PMC 4883399. PMID 27196909.
  12. ↑ Sheldon, John (2019-06-25). "French IoT Satellite Company Kinéis Announces Strategic Partnerships With Objenious And Wize Alliance". SpaceWatch.Global. Retrieved 2019-08-02.
  13. ↑ "SIGFOX Technology". Retrieved 2016-02-01.
  14. ↑ "What is LoRaWAN?". Link Labs. Retrieved 2023-01-09.
  15. ↑ Jesus Sanchez-Gomez; Ramon Sanchez-Iborra (2017). "Transmission Technologies Comparison for IoT Communications in Smart-Cities". GLOBECOM 2017 - 2017 IEEE Global Communications Conference. pp. 1–6. doi:10.1109/GLOCOM.2017.8254530. ISBN 978-1-5090-5019-2. S2CID 44010035.
  16. ↑ "ELTRES Technology". Sony Semiconductor Solutions Group. Retrieved 2022-08-10.
  17. ↑ IEEE Standard for Information technology--Telecommunications and information exchange between systems - Local and metropolitan area networks--Specific requirements - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 2: Sub 1 GHZ License Exempt Operation. doi:10.1109/IEEESTD.2017.7920364. ISBN 978-1-5044-3911-4.
[edit]
Retrieved from "https://en.wikipedia.org/w/index.php?title=Wide_area_network&oldid=1376178907"