Internet

== Performance ==
As the Internet is a heterogeneous network, its physical characteristics, including, for example the [[Bit rate|data transfer rates]] of connections, vary widely. It exhibits [[Emergence#World Wide Web and the Internet|emergent phenomena]] that depend on its large-scale organization.<ref>{{cite journal |last1=Albert |first1=Réka |last2=Jeong |first2=Hawoong |last3=Barabási |first3=Albert-László |s2cid=4419938 |title=Diameter of the World-Wide Web |journal=Nature |date=9 September 1999 |volume=401 |issue=6749 |pages=130–131 |doi=10.1038/43601|arxiv=cond-mat/9907038 |bibcode=1999Natur.401..130A }}</ref>

===Traffic volume===
{{Latest Global Internet traffic}}
The volume of [[Internet traffic]] is difficult to measure because no single point of measurement exists in the multi-tiered, non-hierarchical topology. Traffic data may be estimated from the aggregate volume through the peering points of the [[Tier 1 network]] providers, but traffic that stays local in large provider networks may not be accounted for.

=== Outages ===
An [[Internet blackout]] or outage can be caused by local signaling interruptions. Disruptions of [[submarine communications cable]]s may cause blackouts or slowdowns to large areas, such as in the [[2008 submarine cable disruption]]. Less-developed countries are more vulnerable due to the small number of high-capacity links. Land cables are also vulnerable, as in 2011 when a woman digging for scrap metal severed most connectivity for the nation of Armenia.<ref>{{cite news|work=The Guardian |url=https://www.theguardian.com/world/2011/apr/06/georgian-woman-cuts-web-access |title=Georgian woman cuts off web access to whole of Armenia |date=6 April 2011 |access-date=11 April 2012 |url-status=live |archive-url=https://web.archive.org/web/20130825075603/http://www.theguardian.com/world/2011/apr/06/georgian-woman-cuts-web-access |archive-date=25 August 2013 }}</ref> Internet blackouts affecting almost entire countries can be achieved by governments as a form of [[Internet censorship]], as in the blockage of the [[Internet in Egypt]], whereby approximately 93%<ref name="renesys1">{{cite web| last =Cowie| first =James| title =Egypt Leaves the Internet| publisher =Renesys| url =http://www.renesys.com/blog/2011/01/egypt-leaves-the-internet.shtml| access-date =28 January 2011| archive-url =https://web.archive.org/web/20110128080518/http://www.renesys.com/blog/2011/01/egypt-leaves-the-internet.shtml| archive-date =28 January 2011}}</ref> of networks were without access in 2011 in an attempt to stop mobilization for [[Egyptian Revolution of 2011|anti-government protests]].<ref>{{cite news|url=https://www.bbc.co.uk/news/technology-12306041 |work=BBC News |title=Egypt severs internet connection amid growing unrest |date=28 January 2011 |url-status=live |archive-url=https://web.archive.org/web/20120123164134/http://www.bbc.co.uk/news/technology-12306041 |archive-date=23 January 2012 }}</ref>

=== Energy use ===
Estimates of the Internet's [[electricity usage]] have been the subject of controversy, according to a 2014 peer-reviewed research paper that found claims differing by a factor of 20,000 published in the literature during the preceding decade, ranging from 0.0064 [[kilowatt hour]]s per gigabyte transferred (kWh/GB) to 136 kWh/GB.<ref name="Environmental Impact Assessment Review">{{Cite journal|last1=Coroama|first1=Vlad C.|last2=Hilty|first2=Lorenz M.|date=February 2014|title=Assessing Internet energy intensity: A review of methods and results|url=http://publicationslist.org/data/lorenz.hilty/ref-218/2014_Coroama_Hilty_Assessing_Internet_Energy_Intensity_AAM.pdf|journal=Environmental Impact Assessment Review|language=en|volume=45|pages=63–68|doi=10.1016/j.eiar.2013.12.004|access-date=9 March 2020|archive-date=23 September 2020|archive-url=https://web.archive.org/web/20200923042203/http://publicationslist.org/data/lorenz.hilty/ref-218/2014_Coroama_Hilty_Assessing_Internet_Energy_Intensity_AAM.pdf|url-status=live}}</ref> The researchers attributed these discrepancies mainly to the year of reference (i.e. whether efficiency gains over time had been taken into account) and to whether "end devices such as [[personal computer]]s and servers are included" in the analysis.<ref name="Environmental Impact Assessment Review" />

In 2011, academic researchers estimated the overall [[energy use]]d by the Internet to be between 170 and 307 [[gigawatt|GW]], less than two percent of the energy used by humanity. This estimate included the energy needed to build, operate, and periodically replace the estimated 750&nbsp;million [[laptop]]s, a billion [[smart phone]]s and 100&nbsp;million servers worldwide as well as the energy that routers, [[cell tower]]s, [[optical switch]]es, [[Wi-Fi]] transmitters and [[cloud storage]] devices use when transmitting [[Internet traffic]].<ref>{{cite web|first=Jim|last=Giles|title=Internet responsible for 2 per cent of global energy usage|website=New Scientist|date=26 October 2011|url=http://www.newscientist.com/blogs/onepercent/2011/10/307-gw-the-maximum-energy-the.html |archive-date=1 October 2014 |archive-url=https://web.archive.org/web/20141001113334/http://www.newscientist.com/blogs/onepercent/2011/10/307-gw-the-maximum-energy-the.html}},</ref><ref>{{cite book|chapter-url=http://conferences.sigcomm.org/hotnets/2011/papers/hotnetsX-final56.pdf|archive-url=https://web.archive.org/web/20140810075940/http://conferences.sigcomm.org/hotnets/2011/papers/hotnetsX-final56.pdf |archive-date=10 August 2014|first1=Barath|last1=Raghavan|first2=Justin|last2=Ma|title=Proceedings of the 10th ACM Workshop on Hot Topics in Networks |chapter=The energy and emergy of the internet |date=14 November 2011|pages=1–6|location=Cambridge, MA.|publisher=ACM SIGCOMM|doi=10.1145/2070562.2070571|isbn=978-1-4503-1059-8|s2cid=6125953}}</ref> According to a non-peer-reviewed study published in 2018 by [[The Shift Project]] (a French think tank funded by corporate sponsors), nearly 4% of global [[carbon dioxide emissions|CO<sub>2</sub> emissions]] could be attributed to global [[data transfer]] and the necessary infrastructure.<ref>{{cite web|url=https://www.dw.com/en/is-netflix-bad-for-the-environment-how-streaming-video-contributes-to-climate-change/a-49556716|title=Is Netflix bad for the environment? How streaming video contributes to climate change {{!}} DW {{!}} 11.07.2019|last=Cwienk|first=Jeannette|date=11 July 2019|publisher=Deutsche Welle|language=en-GB|access-date=19 July 2019|archive-date=12 July 2019|archive-url=https://web.archive.org/web/20190712203905/https://www.dw.com/en/is-netflix-bad-for-the-environment-how-streaming-video-contributes-to-climate-change/a-49556716|url-status=live}}</ref> The study also said that [[Internet video|online video streaming]] alone accounted for 60% of this data transfer and therefore contributed to over 300&nbsp;million tons of CO<sub>2</sub> emission per year, and argued for new "digital sobriety" regulations restricting the use and size of video files.<ref>{{cite web|url=https://theshiftproject.org/en/article/unsustainable-use-online-video/|title="Climate crisis: The Unsustainable Use of Online Video": Our new report|date=10 July 2019|website=The Shift Project|language=en-GB|access-date=19 July 2019|archive-url=https://web.archive.org/web/20190721144259/https://theshiftproject.org/en/article/unsustainable-use-online-video/|archive-date=21 July 2019|url-status=live}}</ref>
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