Editing Link-state routing protocol (section)

{{short description|Class of routing protocols}}
{{More footnotes needed|date=September 2010}}

'''Link-state routing protocols''' are one of the two main classes of [[routing protocol]]s used in [[packet switching]] networks for [[computer communication]]s, the others being [[distance-vector routing protocol]]s.<ref>{{Cite web |date=2018-05-18 |title=Unicast Routing - Link State Routing |url=https://www.geeksforgeeks.org/unicast-routing-link-state-routing/ |access-date=2024-05-09 |website=GeeksforGeeks |language=en-US}}</ref> Examples of link-state routing protocols include [[Open Shortest Path First]] (OSPF) and [[Intermediate System to Intermediate System]] (IS-IS).<ref>lec10-lsrouting.pdf (princeton.edu)

<nowiki>https://www.cs.princeton.edu/courses/archive/spring23/cos461/lectures/lec10-lsrouting.pdf</nowiki></ref>

The link-state protocol is performed by every ''switching node'' in the network (i.e., nodes which are prepared to forward packets; in the [[Internet]], these are called [[Router (computing)|router]]s).<ref>lecture6.pptx (umich.edu)

<nowiki>https://www.eecs.umich.edu/courses/eecs489/w10/winter10/lectures/lecture6_2.pdf</nowiki></ref> The basic concept of link-state routing is that every node constructs a ''map'' of the connectivity to the network in the form of a [[graph theory|graph]], showing which nodes are connected to which other nodes.<ref>123sp15-lec14.pdf (ucsd.edu)

<nowiki>https://cseweb.ucsd.edu/classes/sp15/cse123-a/lectures/123sp15-lec14.pdf</nowiki></ref> Each node then independently calculates the next best logical ''path'' from it to every possible destination in the network.<ref>link state protocol.pdf (fauser.edu)

<nowiki>http://nuovolabs.fauser.edu/~valeria/materiale-didattico/sistemi-quinta/link%20state%20protocol.pdf</nowiki></ref> Each collection of best paths will then form each node's [[routing table]].<ref>{{Cite web |date=2019-08-12 |title=9.6: Link-State Routing-Update Algorithm |url=https://eng.libretexts.org/Bookshelves/Computer_Science/Networks/Book%3A_An_Introduction_to_Computer_Networks_(Dordal)/09%3A_Routing-Update_Algorithms/9.06%3A_Link-State_Routing-Update_Algorithm |access-date=2024-05-09 |website=Engineering LibreTexts |language=en}}</ref>

This contrasts with distance-vector routing protocols, which work by having each node share its routing table with its neighbors, in a link-state protocol, the only information passed between nodes is ''connectivity related''.<ref>5-routing-part2.pdf (washington.edu)

<nowiki>https://courses.cs.washington.edu/courses/cse461/22sp/slides/5-routing-part2.pdf</nowiki></ref> Link-state algorithms are sometimes characterized informally as each router "telling the world about its neighbors."<ref>{{Cite web |last=Library |first=Broadband |date=2018-08-31 |title=A Closer Look at Routing {{!}} |url=https://broadbandlibrary.com/a-closer-look-at-routing/ |access-date=2024-05-09 |language=en-US}}</ref>