Editing Point-to-Point Protocol (section)

[[File:MLPPP model, topology and encapsulation - en.png|thumb|Point-to-Point Protocol]]
{{Short description|Data link layer communication protocol}}In [[computer network]]ing, '''Point-to-Point Protocol''' ('''PPP''') is a [[data link layer]] (layer 2) [[communication protocol]] between two routers directly without any host or any other networking in between.<ref>{{IETF RFC|1661}}</ref> It can provide loop detection, [[authentication]], transmission [[encryption]],<ref>{{IETF RFC|1968}}</ref> and [[data compression]].

PPP is used over many types of physical networks, including [[serial cable]], [[phone line]], [[Trunking#Trunk line|trunk line]], [[cellular telephone]], specialized radio links, [[ISDN]], and [[Fiber-optic communication|fiber optic links]] such as [[SONET]]. Since IP packets cannot be transmitted over a [[modem]] line on their own without some data link protocol that can identify where the transmitted frame starts and where it ends, [[Internet service provider]]s (ISPs) have used PPP for customer [[dial-up access]] to the [[Internet]].

PPP is used on former [[dial-up networking]] lines.<ref>{{citation |url=https://www.physics.udel.edu/~bnikolic/teaching/phys660/RUTE/rute/node44.html |title=Linux: Rute User's Tutorial and Exposition |section=41. Point-to-Point Protocol -- Dialup Networking |access-date=2024-08-20}}</ref> Two derivatives of PPP, [[Point-to-Point Protocol over Ethernet]] (PPPoE) and [[Point-to-Point Protocol over ATM]] (PPPoA), are used most commonly by ISPs to establish a [[digital subscriber line]] (DSL) Internet service LP connection with customers.