{{Short description|Architecture that uses edge devices}} [[File:OpenFog Consortium.jpg|thumb|right|The OpenFog Consortium was an association of major tech companies aimed at standardizing and promoting fog computing.]] '''Fog computing'''<ref name=":2">{{Cite web|url=https://www.sigmobile.org/mobicom/2011/vanet2011/program.html|title=Connected Vehicles, the Internet of Things, and Fog Computing, The 8th ACM International Workshop on VehiculAr Inter-NETworking (VANET 2011), Las Vegas, NV, USA|last=Bonomi|first=Flavio|date=September 19–23, 2011|website=www.sigmobile.org|access-date=2019-08-07}}</ref><ref name=":3">{{Cite web|url=https://sites.google.com/site/eon2011/topics|title=Cloud and Fog Computing: Trade-offs and Applications. EON-2011 Workshop, International Symposium on Computer Architecture (ISCA 2011), San Jose, CA, USA|last=Bonomi|first=Flavio|date=June 4–8, 2011|website=sites.google.com|access-date=2019-08-07|archive-date=2020-07-31|archive-url=https://web.archive.org/web/20200731165630/https://sites.google.com/site/eon2011/topics|url-status=dead}}</ref> or '''fog networking''', also known as '''fogging''',<ref>{{Cite web|url=http://blogs.cisco.com/perspectives/iot-from-cloud-to-fog-computing|title=IoT, from Cloud to Fog Computing|website=blogs@Cisco - Cisco Blogs|language=en-US|access-date=2017-04-07|date=2015-03-25}}</ref><ref>{{Cite web|url=http://www.webopedia.com/TERM/F/fog-computing.html|title=What Is Fog Computing? Webopedia Definition|website=www.webopedia.com|date=18 December 2014 |language=en|access-date=2017-04-07}}</ref> is an architecture that uses edge devices to carry out a substantial amount of computation (edge computing), storage, and communication locally and routed over the Internet backbone.
== Concept == In 2011, the need to extend cloud computing with fog computing emerged, in order to cope with huge number of IoT devices and big data volumes for real-time low-latency applications.<ref name=":12">{{Cite book |last1=Bonomi |first1=Flavio |last2=Milito |first2=Rodolfo |last3=Zhu |first3=Jiang |last4=Addepalli |first4=Sateesh |title=Proceedings of the first edition of the MCC workshop on Mobile cloud computing |chapter=Fog computing and its role in the internet of things |date=2012-08-17 |publisher=ACM |isbn=9781450315197 |pages=13–16 |doi=10.1145/2342509.2342513 |s2cid=207196503}}</ref><ref>{{Cite journal |last1=Azzolini |first1=Damiano |last2=Forti |first2=Stefano |last3=Ielo |first3=Antonio |date=September 2025 |title=Continuous reasoning for adaptive container image distribution in the cloud–edge continuum |url=https://link.springer.com/10.1007/s10586-025-05253-9 |journal=Cluster Computing |language=en |volume=28 |issue=7 |article-number=461 |doi=10.1007/s10586-025-05253-9 |issn=1386-7857|url-access=subscription }}</ref> Fog computing, much like edge computing, is intended for distributed computing where numerous "peripheral" devices connect to a cloud. The word "fog" refers to its cloud-like properties, but closer to the "ground", i.e. IoT devices.<ref name=":0" /> Many of these devices will generate voluminous raw data (e.g., from sensors), and rather than forward all this data to cloud-based servers to be processed, the idea behind fog computing is to do as much processing as possible using computing units co-located with the data-generating devices, so that processed rather than raw data is forwarded, and bandwidth requirements are reduced. An additional benefit is that the processed data is most likely to be needed by the same devices that generated the data, so that by processing locally rather than remotely, the latency between input and response is minimized. This idea is not entirely new: in non-cloud-computing scenarios, special-purpose hardware (e.g., signal-processing chips performing fast Fourier transforms) has long been used to reduce latency and reduce the burden on a CPU.
Fog networking consists of a control plane and a data plane. For example, on the data plane, fog computing enables computing services to reside at the edge of the network as opposed to servers in a data-center. Compared to cloud computing, fog computing emphasizes proximity to end-users and client objectives (e.g. operational costs, security policies,<ref>{{cite journal |last1=Forti |first1=Stefano |last2=Ferrari |first2=Gian-Luigi |last3=Brogi |first3=Antonio |title=Secure Cloud-Edge Deployments, with Trust |journal=Future Generation Computer Systems |date=January 2020 |volume=102 |pages=775–788 |doi=10.1016/j.future.2019.08.020|doi-access=free |arxiv=1901.05347 }}</ref> resource exploitation), dense geographical distribution and context-awareness (for what concerns computational and IoT resources), latency reduction and backbone bandwidth savings to achieve better quality of service<ref>{{Cite journal|last1=Brogi|first1=Antonio|last2=Forti|first2=Stefano|date=2017|title=QoS-aware Deployment of IoT Applications Through the Fog|journal=IEEE Internet of Things Journal|volume=PP|issue=99|pages=1185–1192|doi=10.1109/JIOT.2017.2701408|bibcode=2017IITJ....4.1185B|s2cid=2880664|issn=2327-4662|url=http://eprints.adm.unipi.it/2362/1/paper.pdf|archive-date=2024-04-14|access-date=2019-09-02|archive-url=https://web.archive.org/web/20240414195708/http://eprints.adm.unipi.it/2362/1/paper.pdf|url-status=dead}}</ref> and edge analytics/stream mining, resulting in superior user-experience<ref name="CiscoFog">Cisco RFP-2013-078. Fog Computing, Ecosystem, Architecture and Applications: ''[http://research.cisco.com/research#rfp-2013078] {{Webarchive|url=https://web.archive.org/web/20200119015130/http://research.cisco.com/research#rfp-2013078|date=2020-01-19}}'' Also available from the Internet Archive: ''[https://web.archive.org/web/20140922061044/http://www.cisco.com/web/about/ac50/ac207/crc_new/university/RFP/rfp13078.html].''</ref> and redundancy in case of failure while it is also able to be used in Assisted Living scenarios.<ref>{{Cite journal|last1=Nikoloudakis|first1=Y.|last2=Panagiotakis|first2=S.|last3=Markakis|first3=E.|last4=Pallis|first4=E.|last5=Mastorakis|first5=G.|last6=Mavromoustakis|first6=C. X.|last7=Dobre|first7=C.|date=November 2016|title=A Fog-Based Emergency System for Smart Enhanced Living Environments|journal=IEEE Cloud Computing|volume=3|issue=6|pages=54–62|doi=10.1109/mcc.2016.118|bibcode=2016IClCo...3f..54N |s2cid=25475572|issn=2325-6095}}</ref><ref>{{Cite web|url=https://spectrum.ieee.org/what-comes-after-the-cloud-how-about-the-fog|title=What Comes After the Cloud? How About the Fog?|website=IEEE Spectrum: Technology, Engineering, and Science News|language=en|access-date=2017-04-07}}</ref><ref>{{Cite news|url=http://www.channelnomics.com/channelnomics-us/news/2370241/is-there-a-buzz-over-fog-computing|title=Is There a Buzz Over Fog Computing?|work=Channelnomics|access-date=2017-04-07|language=en|archive-date=2016-10-27|archive-url=https://web.archive.org/web/20161027223133/http://www.channelnomics.com/channelnomics-us/news/2370241/is-there-a-buzz-over-fog-computing|url-status=dead}}</ref><ref>{{Cite news|url=http://www.natlawreview.com/article/new-solutions-horizon-fog-or-edge-computing|title=New Solutions on the Horizon—"Fog" or "Edge" Computing?|work=The National Law Review|access-date=2017-04-07}}</ref><ref name="backToFut">Cloud Evolution: Back to the Future?: ''[http://www.1cloudroad.com/cloud-evolution-back-to-the-future/] {{Webarchive|url=https://web.archive.org/web/20151009112050/http://www.1cloudroad.com/cloud-evolution-back-to-the-future/|date=2015-10-09}}.''</ref><ref>{{Cite journal|last1=Arkian|first1=Hamid Reza|last2=Diyanat|first2=Abolfazl|last3=Pourkhalili|first3=Atefe|date=2017-03-15|title=MIST: Fog-based data analytics scheme with cost-efficient resource provisioning for IoT crowdsensing applications|journal=Journal of Network and Computer Applications|volume=82|pages=152–165|doi=10.1016/j.jnca.2017.01.012}}</ref>
Fog networking supports the Internet of Things (IoT) concept, in which most of the devices used by humans on a daily basis will be connected to each other. Examples include phones, wearable health monitoring devices, connected vehicle and augmented reality using devices such as the Google Glass.<ref name="iotCisco">Bonomi, F., Milito, R., Zhu, J., and Addepalli, S. [https://www.researchgate.net/profile/Rodolfo_Milito/publication/235409978_Fog_Computing_and_its_Role_in_the_Internet_of_Things/links/0deec531f19946228c000000/Fog-Computing-and-its-Role-in-the-Internet-of-Things.pdf Fog Computing and its Role in the Internet of Things]. In Proc of MCC (2012), pp. 13-16.''[http://dl.acm.org/citation.cfm?id=2342513].''</ref><ref name="iot1">Cisco-Delivers-Vision-of-Fog-Computing-to-Accelerate-Value-from-Billions-of-Connected-Devices: ''[http://newsroom.cisco.com/release/1334100/Cisco-Delivers-Vision-of-Fog-Computing-to-Accelerate-Value-from-Billions-of-Connected-Devices].''</ref><ref name="iotOutCloudFog">IoT: Out Of The Cloud & Into The Fog: ''[http://www.networkcomputing.com/cloud-infrastructure/iot-out-of-the-cloud-and-into-the-fog/a/d-id/1298101] {{Webarchive|url=https://web.archive.org/web/20151223132905/http://www.networkcomputing.com/cloud-infrastructure/iot-out-of-the-cloud-and-into-the-fog/a/d-id/1298101|date=2015-12-23}}.''</ref><ref name="iotdistIntelligence">Distributed intelligence and IoT fog: ''[http://www.insightaas.com/distributed-intelligence-and-iot-fog-2].''</ref><ref name="iotDataWhere">Fog Computing Keeps Data Right Where the Internet of Things Needs It: ''[http://www.biztechmagazine.com/article/2014/08/fog-computing-keeps-data-right-where-internet-things-needs-it].''</ref> IoT devices are often resource-constrained and have limited computational abilities to perform cryptography computations. A fog node can provide security for IoT devices by performing these cryptographic computations instead.<ref>{{Cite journal|last1=Alrawais|first1=Arwa|last2=Alhothaily|first2=Abdulrahman|last3=Hu|first3=Chunqiang|last4=Cheng|first4=Xiuzhen|author4-link= Xiuzhen Cheng |date=March 2017|title=Fog Computing for the Internet of Things: Security and Privacy Issues|journal=IEEE Internet Computing|volume=21|issue=2|pages=34–42|doi=10.1109/MIC.2017.37|bibcode=2017IIC....21b..34A |s2cid=18074495|issn=1089-7801}}</ref>
SPAWAR, a division of the US Navy, is prototyping and testing a scalable, secure Disruption Tolerant Mesh Network to protect strategic military assets, both stationary and mobile. Machine-control applications, running on the mesh nodes, "take over", when Internet connectivity is lost. Use cases include Internet of Things e.g. smart drone swarms.<ref>''[http://meshdynamics.com/documents/ABSTRACTED-NETWORK-FOR-IOT.pdf].''</ref>
The University of Melbourne is addressing the challenges of collecting and processing data from cameras, ECG devices, laptops, smartphones, and IoT devices with its project FogBus 2, which uses edge/fog and Oracle Cloud Infrastructure to process data in real-time.<ref>{{Cite web |last=Morris-Reade |first=Ryan |date=2022-02-16 |title=University of Melbourne uses Oracle Cloud to harness the power of IoT |url=https://securitybrief.com.au/story/university-of-melbourne-uses-oracle-cloud-to-harness-the-power-of-iot |access-date=2022-04-18 |website=SecurityBrief Australia |language=en}}</ref>
ISO/IEC 20248 provides a method whereby the data of objects identified by edge computing using Automated Identification Data Carriers (AIDC), a barcode and/or RFID tag, can be read, interpreted, verified and made available into the "Fog" and on the "Edge," even when the AIDC tag has moved on.<ref>{{Cite book|url=https://books.google.com/books?id=dupGDgAAQBAJ&dq=ISO/IEC+20248+provides+a+method+whereby+the+data+of+objects+identified+by+edge+computing+using+Automated+Identification+Data+Carriers+%5BAIDC%5D,+a+barcode+and/or+RFID+tag,+can+be+read,+interpreted,+verified+and+made+available+into+the+%22Fog%22+and+on+the+%22Edge%22+even+when+the+AIDC+tag+has+moved+on.&pg=PA157|title=Mobile Cloud Computing: Foundations and Service Models|last1=Huang|first1=Dijiang|last2=Wu|first2=Huijun|date=2017-09-08|publisher=Morgan Kaufmann|isbn=9780128096444|language=en}}</ref> <!--Eassy like material hidden: == Motivation == There are many factors that make this an interesting paradigm to study. Each client/edge device in the past several years as become powerful in its capabilities. For instance, the original iPhone had a single core 412 MHz ARM processor with 128 MB RAM and 8 GB storage space. The current iPhone 5S on the other hand carries a dual-core 1.3 GHz Apple A7 processor with 1GB RAM, 64 GB storage space and enhanced GPU capabilities. Intel's mobile chip Atom and Nvidia's Tegra too promise near similar specifications. The increase in strength and capabilities implies complex functionality such as CPU/GPU intensive gaming, powerful location/context tracking sensors and enhanced storage.
Fog computing can be much more cognitive of end user application experience since it is much "closer" to the data then traditional cloud computing. Due to the rise of encrypted traffic and multipath-TCP in the core network, the network provider and the cloud service provider are often unable to extract and understand features specific to the users. Fog applications are not as limited since they may often reside on or near the end user, granting it access to raw user data.
The need for fog applications has been brought further into focus by the clear trend towards cell densification in the 5G framework with multiple small base-stations covering shorter areas. Can they act as miniature LTE-cores coordinating with a centralized LTE core serving only those functionalities that cannot be carried out by the edge?
== Architecture == The functionality of Fog networking can be studied according to the traditional functional planes
EDD (Edge-driven Data Center): On the data-plane, distributed data centers, mobile CDN, and edge caching are various manifestations of the Fog. And a goal of Fog networking research is to investigate the optimization of resources that are virtualized, pooled, and shared in unpredictable way. EDC (Edge-driven Control Plane): On the (much less appreciated) control plane and its many functionalities, Fog Networking revisits the role of the edge devices in network architectures as an integral part of the control plane that monitors, measures, and manages the network.
== Applications == While there has been many applications in the past in the world of P2P networks, sensor networks and mobile adhoc networks (MANETs) there are many applications that can be conceived such as:
* Edge caching/BW management at home gateway/small cell (industrial automation) * Edge analytics and real-time stream-mining * IoT session management and signaling load optimization * Client-driven distributed beam-forming/content sharing * Clients' idle computing/storage resource pooling * Cloudlets/Mobile CDN * FlashLinQ/LTE Direct/WiFi Direct/AirDrop * Over The Top (OTT) content management -->
==History== The term "fog computing" was first developed by Cisco in 2012.<ref>{{Cite journal |last1=Patel |first1=Sandipkumar |last2=Patel |first2=Ritesh |date=2022 |title=Fog Computing: A Comprehensive Analysis of Simulation Tools, Applications and Research Challenges with Use Cases |url=http://www.jestr.org/downloads/Volume15Issue3/fulltext81532022.pdf |journal=Journal of Engineering Science and Technology Review |volume=15 |issue=3 |pages=63–83 |doi=10.25103/jestr.153.08|s2cid=251463942 }}</ref> November 19, 2015, Cisco Systems, ARM Holdings, Dell, Intel, Microsoft, and Princeton University, founded the OpenFog Consortium to promote interests and development in fog computing.<ref>{{Cite news|url=https://www.forbes.com/sites/janakirammsv/2016/04/18/is-fog-computing-the-next-big-thing-in-internet-of-things/2/#1971ac3a34c9|title=Is Fog Computing the Next Big Thing in the Internet of Things|last=Janakiram|first=MSV|date=18 April 2016|work=Forbes Magazine|access-date=18 April 2016}}</ref> Cisco Sr. Managing-Director Helder Antunes became the consortium's first chairman and Intel's Chief IoT Strategist Jeff Fedders became its first president.<ref>{{Cite web|url=https://www.iiconsortium.org/index.htm|title=Industrial Internet Consortium|website=www.iiconsortium.org}}</ref>
==Definition== Both cloud computing and fog computing provide storage, applications, and data to end-users. However, fog computing is closer to end-users and has wider geographical distribution.<ref>F. Bonomi, R. Milito, J. Zhu, and S. Addepalli, "Fog computing and its role in the internet of things," in Proceedings of the First Edition of the MCC Workshop on Mobile Cloud Computing, ser. MCC'12. ACM, 2012, pp. 13–16.</ref>
'Cloud computing' is the practice of using a network of remote servers hosted on the Internet to store, manage, and process data, rather than a local server or a personal computer.<ref>{{Cite web|url=https://en.oxforddictionaries.com/definition/cloud_computing|archive-url=https://web.archive.org/web/20160927033704/https://en.oxforddictionaries.com/definition/cloud_computing|url-status=dead|archive-date=September 27, 2016|title=cloud computing {{!}} Definition of cloud computing in English by Oxford Dictionaries|website=Oxford Dictionaries {{!}} English|access-date=2017-11-10}}</ref>
Also known as edge computing or fogging, fog computing facilitates the operation of compute, storage, and networking services between end devices and cloud computing data centers.
National Institute of Standards and Technology in March 2018 released a definition of fog computing adopting much of Cisco's commercial terminology as NIST Special Publication 500-325, ''Fog Computing Conceptual Model'', that defines fog computing as a horizontal, physical or virtual resource paradigm that resides between smart end-devices and traditional cloud computing or data center.<ref name=":0">{{Cite web|url=https://newsroom.cisco.com/feature-content?type=webcontent&articleId=1894659|title=Fog brings the cloud closer to the ground: Cisco innovates in fog computing|website=newsroom.cisco.com|language=en-US|access-date=2019-01-24}}</ref> This paradigm supports vertically-isolated, latency-sensitive applications by providing ubiquitous, scalable, layered, federated, distributed computing, storage, and network connectivity. Thus, fog computing is most distinguished by distance from the edge. In the theoretical model of fog computing, fog computing nodes are physically and functionally operative between edge nodes and centralized cloud.<ref>{{Cite journal|last1=Sarkar|first1=S.|last2=Misra|first2=S.|date=2016|title=Theoretical modelling of fog computing: a green computing paradigm to support IoT applications|url=https://ieeexplore.ieee.org/document/7437623|archive-url=https://web.archive.org/web/20161006142611/http://ieeexplore.ieee.org/document/7437623/|url-status=dead|archive-date=October 6, 2016|journal=IET Networks|volume=5|issue=2|pages=23–29|doi=10.1049/iet-net.2015.0034|issn=2047-4954|access-date=February 3, 2019|url-access=subscription}}</ref> Much of the terminology is undefined, including key architectural terms like "smart", and the distinction between fog computing from edge computing is not generally agreed.
=== Differences from edge computing === While edge computing is typically referred to the location where services are instantiated, fog computing implies distribution of the communication, computation, storage resources, and services on or close to devices and systems in the control of end-users.<ref>{{Cite book |last=Zhang |first=Chiang |title=2017 European Conference on Networks and Communications (EuCNC) |chapter=Reliable capacity provisioning for distributed cloud/Edge/Fog computing applications |url=http://nbn-resolving.de/urn:nbn:de:bsz:289-oparu-4539-1 |date=2016 |isbn=978-1-5386-3873-6 |volume=3 |pages=854–864 |doi=10.1109/EuCNC.2017.7980667 |hdl=11572/272828 |issue=6 |s2cid=19836815}}</ref><ref>{{Cite journal |last=Ostberg |display-authors=etal |title=Fog and IoT: An Overview of Research Opportunities |journal=IEEE Internet of Things Journal |date=2017 |volume=3 |issue=6 |pages=854–864 |doi=10.1109/JIOT.2016.2584538 |s2cid=207018722}}</ref> Fog computing is a medium weight and intermediate level of computing power.<ref>{{Cite journal |last1=Perera |first1=Charith |last2=Qin |first2=Yongrui |last3=Estrella |first3=Julio C. |last4=Reiff-Marganiec |first4=Stephan |last5=Vasilakos |first5=Athanasios V. |date=2017-10-09 |title=Fog Computing for Sustainable Smart Cities: A Survey |url=http://eprints.hud.ac.uk/id/eprint/31927/8/__nas01_librhome_librsh3_Desktop_acmsmall-sample.pdf |journal=ACM Computing Surveys |volume=50 |issue=3 |pages=32 |arxiv=1703.07079 |bibcode=2017arXiv170307079P |doi=10.1145/3057266 |issn=0360-0300 |s2cid=12675271}}</ref> Rather than a substitute, fog computing often serves as a complement to cloud computing.<ref>{{Cite journal |last=Matt |first=Christian |date=2018-04-19 |title=Fog Computing |url=https://boris.unibe.ch/121416/3/Matt%20%282018%29_Fog%20Computing_postprint.pdf |journal=Business & Information Systems Engineering |language=en |volume=60 |issue=4 |pages=351–355 |doi=10.1007/s12599-018-0540-6 |issn=2363-7005 |s2cid=51874973}}</ref> Fog computing is more energy-efficient than cloud computing.<ref>{{Cite journal |last1=Sarkar |first1=S. |last2=Chatterjee |first2=S. |last3=Misra |first3=S. |date=2018 |title=Assessment of the Suitability of Fog Computing in the Context of Internet of Things |journal=IEEE Transactions on Cloud Computing |volume=6 |issue=1 |pages=46–59 |doi=10.1109/TCC.2015.2485206 |bibcode=2018ITCC....6...46S |issn=2168-7161 |s2cid=3823420}}</ref>
==Standards== IEEE adopted the fog computing standards proposed by OpenFog Consortium.<ref name=IEEE>{{Cite web|url=https://standards.ieee.org/ieee/1934/7137/|title=IEEE 1934-2018 - IEEE Standard for Adoption of OpenFog Reference Architecture for Fog Computing|website=IEEE}}</ref>
==See also== * Fog robotics * Edge computing * Dew computing * Mobile edge computing * OpenFog Consortium
== References == {{reflist|30em}}
{{Embedded systems}} {{Ambient intelligence}}
Category:Post-cloud computing architecture Category:Distributed computing architecture Category:Load balancing (computing) Category:Networking hardware Category:Internet of things Category:Ambient intelligence