ARPA and Packet Switching Network?

Saw a show on the history channel about how ARPA sponsored research
into what became the Internet. They showed the first "packet" switch
at UCLA which was cool. The show stated that the ARPA project was to
get computers to communication easily as they were islands of
independent processing. But I thought there was synchronous serial
communications between computers well before this and that the main
ARPA goal was to develop a communication network that could withstand
a nuclear attack by re-routing packets around damaged switching nodes?

Dan

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