Connect to the internet

yea.....sounds silly but please read.

[snowman]

Once upon a time, people connected their computers to each other via phone lines.

Networked together, each computer being open to the others on the network, formed an inter connected network.

Now suppose I have a computer (mine is a Mac) with more than enough speed, RAM and hard drive storage for my purposes. I store files and have access to an internet pipeline through an ISP.

And I could select only which directories I would open via file sharing.

1) Why do I need an ISP? It seems a little redundant. Why cannot I connect to the pipeline directly via my firewall?

2) I would set up my own directory/domain/whatever. What prevents me, as a user, from doing this?

thanks for your patience with a question that has probably been answered many times before.

[DaveAtIFG]

It's an interesting question that I've not seen asked before. Here's an analogy.

Gasoline is distributed to Arizona from California and Texas, where it has been refined, via huge pipelines and distribution networks. If you tried to "pump gas" directly from one of these pipelines... You are not equipped to handle the volume and the distro networks are not equipped to do retail sales.

I'm hazy on specifics but high speed Internet connections come in various performance categories, Backbone (the pipeline), OC3 (storage tanks), T1 (gasoline tanker trucks), etc. An ISP steps connections down to a rate end users can handle and multiplexes to many end users (the gas station).

Some gasoline distributers also have retail divisions and an ISP such as Earthlink might be thought of as similar, both a distributer and a retailer.

[DrDoc]

The ISP also handles and restricts your IP. Otherwise anyone could connect with any IP... Plus, do you realize how hard it would be to set up a major network like that? Now, you are still connected to the pipeline, just through a smaller network, which in turn is part of a bigger network, which in itself is part of an even bigger network, which is then connected directly to the great void.

Same reason why there are local post offices, and gas stations (as per Dave's example)...
It would be chaos otherwise :)