[[Donald Davies|Donald Davies']] team at the [[National Physical Laboratory (United Kingdom)|National Physical Laboratory]] introduced the concept of an alternating bit protocol in 1968 for the [[NPL network]].<ref name=":3">{{Cite journal |last=Cambell-Kelly |first=Martin |date=1987 |title=Data Communications at the National Physical Laboratory (1965-1975) |url=https://archive.org/details/DataCommunicationsAtTheNationalPhysicalLaboratory |journal=Annals of the History of Computing |language=en |volume=9 |issue=3/4 |pages=221–247 |doi=10.1109/MAHC.1987.10023 |s2cid=8172150}}</ref> An ABP was used by the [[ARPANET]] for Host to IMP communication (the [[1822 protocol]]) and by the [[European Informatics Network]].<ref>{{Cite book|last=Davies|first=Donald Watts|url=https://archive.org/details/computernetworks00davi|title=Computer networks and their protocols|date=1979|publisher=Chichester, [Eng.] ; New York : Wiley|others=Internet Archive|pages=[https://archive.org/details/computernetworks00davi/page/206 206]|url-access=registration}}</ref><ref>{{Cite web |title=ARPANET is now 50 years old {{!}} Inria |url=https://www.inria.fr/en/arpanet-now-50-years-old |access-date=2022-11-10 |website=www.inria.fr |language=en}}</ref><ref>{{Cite book |last=Brügger |first=Niels |url=https://books.google.com/books?id=kqyJEAAAQBAJ&newbks=0&printsec=frontcover&pg=PT82&dq=gerard+le+lann+%22sliding+window%22+scheme&hl=en |title=Oral Histories of the Internet and the Web |last2=Goggin |first2=Gerard |date=2022-10-25 |publisher=Taylor & Francis |isbn=978-1-000-79781-7 |language=en}}</ref>