[id0ntw4ntit]

> There are too many Internet nodes for it to work in this way. We can't provide a direct, uninterruptible path from each machine to each other machine it wants to talk to.

Is this true? Isn't a direct, uninterruptible path from each machine to the other a requirement for communication? The path must proceed through complex switching systems, like in the analog days, yes.

What is meant by the statement that it is no longer electrically equivalent to a single wire?

[roelschroeven]

In old telephone systems, each telephone had a dedicated wire to the central, and centrals had a number of dedicated wires between, each one of which could be used for one conversation at a time. Setting up a call involved physically switching your line to one of the wires to the next central, and from there to the next, until the last central where there was a physical connection made to the line the person you were calling (unless if at some place no free wires were available; then you got a busy signal). Once all the switches were put in the correct position, there was practically speaking one uninterrupted wire between the two phones. If you were to put a voltage spike on your line, that could be measured at the other end. At the end of the call the switches were put in another position, and there was no electrical connection between those phones anymore.

In a packet-switched network, there is no direct electrical connection between two arbitrary nodes; there is only an electrical connection between your device and the first router, and between any router and the next one.

Of course nowadays telephone lines don't work with physical dedicated wires anymore either. It's all digitized and multiplexed now.

[alfons_foobar]

I think this refers to circuit switching (in the old telephone networks, when you called someone, the connection had to be physically established at the "intersections" by the phone network operators) vs. packet switching (where the underlying network is not changed, instead the data packet is forwarded from one "intersection" to the next and reaches its destination eventually).