{"id":62,"date":"2025-12-02T10:34:51","date_gmt":"2025-12-02T10:34:51","guid":{"rendered":"https:\/\/group5.ai-research.it.ntnu.no\/?p=62"},"modified":"2025-12-11T00:33:17","modified_gmt":"2025-12-11T00:33:17","slug":"packet-switching-vs-circuit-switching-how-data-travels-across-networks","status":"publish","type":"post","link":"https:\/\/group5.ai-research.it.ntnu.no\/?p=62","title":{"rendered":"Packet Switching vs Circuit Switching: How Data Travels Across Networks"},"content":{"rendered":"\n

Packet Switching and Circuit Switching are two key ways for data to travel in networks. <\/h4>\n\n\n\n
<\/div>\n\n\n\n
Definitions<\/h5>\n\n\n\n

Circuit Switching<\/strong> was used for phone calls back in the days. It creates a dedicated line between you and the person you’re calling. The line stays open during the call for instant, clear voice but is reserved for that call only. It is a communication method where a dedicated connection path is establised and reserved for the entire duration between two endpoints.
Example: Old landline phones<\/p>\n\n\n\n

Today, Packet Switching <\/strong>dominates, while Circuit Switching is almost phased out. It works over the internet, breaking voice\/video into packets that travel shared routes. Your data splits into smaller packets that find their own way, like puzzle pieces.
Example: WhatsApp calls, Netflix streaming, browsing. It is a data transmission method where messages are divided into packets that are sent independently across a network and reassembled at the destination.<\/p>\n\n\n\n

Both have played important roles in digital communication.<\/p>\n\n\n\n

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Photo: Britannica.com – Packet Switched-Network<\/a><\/figcaption><\/figure>\n\n\n\n
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Timeline <\/h4>\n\n\n\n

to briefly visualize the history of packet switching and circuit switching<\/p>\n\n\n\n

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1870s – 1890s<\/p><\/div><\/div>

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photo: Getty Images, Britannica.com <\/figcaption><\/figure>\n\n\n\n

Circuit Switching<\/h3>\n\n\n\n

The first manual switchboard lights up in New Haven, Connecticut. Operators connecting callers physically with path cords. Circuits for voice; no sharing and a private path until the call ends. <\/p>\n\n\n\n

Photo:<\/strong> Alexander Graham Bell, who patented the telephone in 1876, inaugurating the 1,520-km (944-mile) telephone link between New York City and Chicago on October 18, 1892.<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div>\n\n\n\n

1920s – 1950s<\/p><\/div><\/div>

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Photo: Science Museum Group Collection<\/a><\/figcaption><\/figure>\n\n\n\n

Crossbar Switches<\/h3>\n\n\n\n

Fully automatic crossbar switches are introduced to make circuit-switched telephony faster and more suitable for big cities and more people.

Photo:<\/strong> Telephone crossbar switch made by Swedish Ericsson, 1921. This switch could support up to 100 callers. <\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div>\n\n\n\n

1962 – 1964<\/p><\/div><\/div>

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Photo: Diane Baldwin\/ RAND<\/a><\/figcaption><\/figure>\n\n\n\n

Packet Switching part 1<\/h3>\n\n\n\n

1962 – 1964, Paul Baran suggests breaking messages into small packages and routing them over a distributed network for less failures. This is the start of Packet Switching

Photo<\/strong>: Paul Baran presenting his work at RAND Alumni Association event in 2009. You can see the network of unmanned nodes on the photo. The nodes would use a scheme called “Hot-Potato-Routing”. <\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div>\n\n\n\n

1965<\/p><\/div><\/div>

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Photo: National Inventors Hall of Fame<\/a><\/figcaption><\/figure>\n\n\n\n

Packet Switching part 2<\/h3>\n\n\n\n

Donald Davies at UK Nation Physical Laboratory develops a packet-switched data network. The word “packet” described the 128-byte datablocks flowing through the system. Way more efficient than circuits.

Photo<\/strong>: Donald Watts Davies<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div>\n\n\n\n

1969 – 1973<\/p><\/div><\/div>

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ARPANET <\/h3>\n\n\n\n
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Photo: Britannica.com – ARPANET<\/a><\/figcaption><\/figure>\n\n\n\n

ARPANET (Advanced Research Projects Agency Network, the first computer network was built at UCLA (Santa Monica, close to where Baran worked). It sends it first packet between UCLA and Stanford, making it one of the first networks demonstrating that packets can link to many different sites.

Photo<\/strong>: Visual representation of the spread of ARPANET in the states, september 1974<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div>\n\n\n\n

1974<\/p><\/div><\/div>

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Modern Internet<\/h3>\n\n\n\n
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Photo: Will Reintzell, Northern Virginia Magazine<\/a><\/figcaption><\/figure>\n\n\n\n

Vinton Cerf and Robert Khan publish the TCP\/IP design. This standardized a packet-based protocol suite that allowed different networks to interconnect and efficiently launching the modern Internet architecture.

Photo:<\/strong> Vinton Cerf and Robert Khan together<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div>\n\n\n\n

1900 – today<\/p><\/div><\/div>

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Modern World<\/h3>\n\n\n\n
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Photo: Nico El Nino\/Shutterstock – slashgear.com – “Evolution of the internet…”<\/a><\/p>\n\n\n\n

The public internet, web, streaming, cloud services, VPN… It all rely on Packet Switching<\/em>, with routers and switches forwarding IP packets across shared links.

Circuit Switching <\/em>is still relevant mainly in legacy telephone networks and some fixed voice systems, but even telephones is gradually migrated to packet-based technologies like VoIP and mobile data.

Photo:<\/strong> Illustration of international connection <\/p>\n\n\n\n

<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div>\n<\/div><\/div><\/div><\/div>\n\n\n\n

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<\/p>\n","protected":false},"excerpt":{"rendered":"

Packet Switching and Circuit Switching are two key ways for data to travel in networks. Definitions Circuit Switching was used for phone calls back in the days. It creates a dedicated line between you and the person you’re calling. The line stays open during the call for instant, clear voice but is reserved for that […]<\/p>\n","protected":false},"author":1,"featured_media":219,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":["post-62","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-technology"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/group5.ai-research.it.ntnu.no\/index.php?rest_route=\/wp\/v2\/posts\/62","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/group5.ai-research.it.ntnu.no\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/group5.ai-research.it.ntnu.no\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/group5.ai-research.it.ntnu.no\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/group5.ai-research.it.ntnu.no\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=62"}],"version-history":[{"count":16,"href":"https:\/\/group5.ai-research.it.ntnu.no\/index.php?rest_route=\/wp\/v2\/posts\/62\/revisions"}],"predecessor-version":[{"id":434,"href":"https:\/\/group5.ai-research.it.ntnu.no\/index.php?rest_route=\/wp\/v2\/posts\/62\/revisions\/434"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/group5.ai-research.it.ntnu.no\/index.php?rest_route=\/wp\/v2\/media\/219"}],"wp:attachment":[{"href":"https:\/\/group5.ai-research.it.ntnu.no\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=62"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/group5.ai-research.it.ntnu.no\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=62"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/group5.ai-research.it.ntnu.no\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=62"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}