[thelist] What goes on under the hood of the Internet?

[Peter Small]

I'm trying to figure out a neat mental model to explain how the Internet
works without having to involve any technical detail. I thought I had a
good idea as to what goes on under the hood until I tried to write down a
simple explanation.  The more I try, the more knowledge gaps I discover.

Starting from the beginning, I make a connection to my ISP. I guess some
application does this by making a telephone connection and in computer
speak identifies itself and presents an appropriate password. The ISP then
allocates my computer a temporary IP address.

Presumably, the ISP then listens out for any messages for this temporary
address and passes them straight on to me. If I send out messages where do
they go? Does the ISP computer simply pass them on, adding my temporary IP
address? If it passes them on, where does it pass them on to? How do they
get to a destination I want them to go to: 1) when I send someone an email
2) when I specify a link in a browser.

Once I'm connected, does my ISP computer keep listening to my connection to
see if I am sending any messages? How does my ISP computer detect the
messages that are being sent to me? Are these messages being routed
directly to it or is it just listening to all messages on the Internet and
selecting those that apply to its own clients?

It's a very hazy picture I have. Everytime I think I'm beginning to
understand, I try to think it all through and a get stumped with another
knowledge gap.

I'd be grateful for a little light...

peter
http:www.petersmall.net