Editing Load balancing (computing) (section)

===Telecommunications===
Load balancing can be useful in applications with redundant communications links.  For example, a company may have multiple Internet connections ensuring network access if one of the connections fails. A [[failover]] arrangement would mean that one link is designated for normal use, while the second link is used only if the primary link fails.

Using load balancing, both links can be in use all the time.  A device or program monitors the availability of all links and selects the path for sending packets. The use of multiple links simultaneously increases the available bandwidth.

====Shortest Path Bridging====
[[TRILL]] (Transparent Interconnection of Lots of Links) facilitates an [[Ethernet]] to have an arbitrary topology, and enables per flow pair-wise load splitting by way of [[Dijkstra's algorithm]], without configuration and user intervention. The catalyst for TRILL was an event at [[Beth Israel Deaconess Medical Center]] which began on 13 November 2002.<ref>{{cite web |title=All Systems Down |url=https://community.cisco.com/legacyfs/online/legacy/0/9/8/140890-All%20Systems%20Down%20-%20Scott%20Berinato(CIO).pdf |website=cio.com |publisher=IDG Communications, Inc. |access-date=9 January 2022 |archive-url=https://web.archive.org/web/20200923200221if_/https://community.cisco.com/legacyfs/online/legacy/0/9/8/140890-All%20Systems%20Down%20-%20Scott%20Berinato(CIO).pdf |archive-date=23 September 2020 |url-status=dead}}</ref><ref>{{cite web |title=All Systems Down |url=https://www.computerworld.com/article/2581420/all-systems-down.html |website=cio.com |publisher=IDG Communications, Inc. |access-date=9 January 2022 |archive-url=https://web.archive.org/web/20220109020703/https://www.computerworld.com/article/2581420/all-systems-down.html |archive-date=9 January 2022 |url-status=dead}}</ref>  The concept of Rbridges<ref>{{cite web |title=Rbridges: Transparent Routing |url=https://courses.cs.washington.edu/courses/cse590l/05sp/papers/rbridges.pdf |website=courses.cs.washington.edu |publisher=Radia Perlman, Sun Microsystems Laboratories |access-date=9 January 2022 |archive-url=https://web.archive.org/web/20220109030037/https://courses.cs.washington.edu/courses/cse590l/05sp/papers/rbridges.pdf |archive-date=9 January 2022 |url-status=dead}}</ref> [sic] was first proposed to the [[Institute of Electrical and Electronics Engineers]] in the year 2004,<ref>{{cite web |title=Rbridges: Transparent Routing |url=https://www.researchgate.net/publication/4102976 |website=researchgate.net |publisher=Radia Perlman, Sun Microsystems; Donald Eastlake 3rd, Motorola}}</ref> whom in 2005<ref>{{cite web |title=TRILL Tutorial |url=http://www.postel.org/rbridge/trill-tutorial.pdf |website=postel.org |publisher=Donald E. Eastlake 3rd, Huawei |access-date=2022-01-14 |archive-date=2023-03-29 |archive-url=https://web.archive.org/web/20230329233902/http://www.postel.org/rbridge/trill-tutorial.pdf |url-status=dead }}</ref> rejected what came to be known as TRILL, and in the years 2006 through 2012<ref>{{cite web |title=IEEE 802.1: 802.1aq - Shortest Path Bridging |url=https://ieee802.org/1/pages/802.1aq.html |website=ieee802.org |publisher=Institute of Electrical and Electronics Engineers }}</ref> devised an incompatible variation known as [[Shortest Path Bridging]].

The IEEE approved the [[IEEE 802.1aq]] standard in May 2012,<ref>{{cite web
 |title = IEEE APPROVES NEW IEEE 802.1aq™ SHORTEST PATH BRIDGING STANDARD
 |publisher = IEEE
 |author = Shuang Yu
 |date = 8 May 2012
 |url = http://standards.ieee.org/news/2012/802.1aq.html
 |access-date = 2 June 2012
 |archive-date = 14 May 2013
 |archive-url = https://web.archive.org/web/20130514211405/http://standards.ieee.org/news/2012/802.1aq.html
 |url-status = dead
 }}</ref> also known as Shortest Path Bridging (SPB). SPB allows all links to be active through multiple equal-cost paths, provides faster convergence times to reduce downtime, and simplifies the use of load balancing in [[Network topology#Mesh|mesh network topologies]] (partially connected and/or fully connected) by allowing traffic to load share across all paths of a network.<ref>{{cite web
 |title = Shortest Path Bridging IEEE 802.1aq Overview
 |publisher = Huawei
 |author = Peter Ashwood-Smith
 |date = 24 Feb 2011
 |url = http://meetings.apnic.net/__data/assets/pdf_file/0012/32007/APRICOT_SPB_Overview.pdf
 |access-date = 11 May 2012
 |archive-url = https://web.archive.org/web/20130515115628/http://meetings.apnic.net/__data/assets/pdf_file/0012/32007/APRICOT_SPB_Overview.pdf
 |archive-date = 15 May 2013
 |url-status = dead
 }}</ref><ref>
{{cite web
 |title = Largest Illinois healthcare system uproots Cisco to build $40M private cloud
 |author = Jim Duffy
 |date = 11 May 2012
 |publisher = PC Advisor
 |quote = Shortest Path Bridging will replace Spanning Tree in the Ethernet fabric.
 |url = http://www.pcadvisor.co.uk/news/internet/3357242/largest-illinois-healthcare-system-uproots-cisco-build-40m-private-cloud/
 |access-date = 11 May 2012
 }}</ref> SPB is designed to virtually eliminate human error during configuration and preserves the plug-and-play nature that established Ethernet as the de facto protocol at Layer 2.<ref name="IEEE">
{{cite news
 |title = IEEE Approves New IEEE 802.1aq Shortest Path Bridging Standard
 |publisher = Tech Power Up
 |date = 7 May 2012
 |url = http://www.techpowerup.com/165594/IEEE-Approves-New-IEEE-802.1aq-Shortest-Path-Bridging-Standard.html
 |access-date = 11 May 2012
 }}</ref>

====Routing 1====
{{further|Routing}}
Many telecommunications companies have multiple routes through their networks or to external networks.  They use sophisticated load balancing to shift traffic from one path to another to avoid [[network congestion]] on any particular link, and sometimes to minimize the cost of transit across external networks or improve [[Reliability (computer networking)|network reliability]].

Another way of using load balancing is in [[network monitoring]] activities. Load balancers can be used to split huge data flows into several sub-flows and use several network analyzers, each reading a part of the original data. This is very useful for monitoring fast networks like [[10 Gigabit Ethernet|10GbE]] or STM64, where complex processing of the data may not be possible at [[wire speed]].<ref>{{cite conference | last1=Noormohammadpour | first1=Mohammad | last2=Raghavendra | first2=Cauligi S. | title=IEEE INFOCOM 2018 - IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS) | chapter=Poster abstract: Minimizing flow completion times using adaptive routing over inter-datacenter wide area networks | publisher=IEEE | date=2018 | isbn=978-1-5386-5979-3 | doi=10.1109/INFCOMW.2018.8406853 | doi-access=free | pages=1–2| arxiv=1802.09080 }}</ref>