...ARPANET was an incremental step from late telegraph systems <a href="en.wikipedia.org/wiki/Plan_55-A">Plan 55</a> to the early Internet. Given the size of a

...ARPANET was an incremental step from late telegraph systems <a href="en.wikipedia.org/wiki/Plan_55-A">Plan 55</a> to the early Internet. Given the size of a typical telegram, transition from message to packet switching was more like a buzzword change. And ARPANET didn't have the end-to-end principle initially, thus functioning very much like late telegraph.