The notion of a possible nuclear war was involved in the evolution of ARPAnet; it was discussed as an example of the kind of extreme interruption which the ARPANet would need to be able to survive. The result of that requirement was the use of TCPIP and the technique of sending each packet by any possible route, letting the packets reassemble at their destination before being passed on to the application layer. This meant that if a line or a node got blown up, an alternate series of jumps could be found. It was a big improvement over the point-to-point connection model of the phone company.

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