Internet questions

Factual Questions
1

I have some questions regarding the Internet:

  1. Is there a backbone which runs around the world or is it a mixture of fiber optic cable, microwave links and satellite links?

  2. I know that a URL is broken down into an IP address but how does it know what IP address corresponds to that URL and how does it kinow which server the site is located on?

2
  1. The software does a Domain Name Server (DNS) lookup, which tells which name (e.g., http://www.straightdope.com) corresponds to which IP (e.g., 65.201.198.8). The DNS is on various servers all through the Internet. Possibly your ISP has one or two. Once it finds the IP, it connects to the server. IPs are unique, so if you know that, you know which computer to go to.
3

  1. There are several “backbones” which most traffic routed a significant distance (ie, not local) go through, just because it’s more efficient to have a few fat pipes than a lot of skinny ones. especially over an ocean.

  2. The I.P. address is the real address of a particular machine on the internet. The machine name (the part of the url that looks like “boards.straightdope.com”) is mapped to the ip by nameservers. There are tiers of nameservers. The top tier is the com or org or net or whatever, that’s where there’s only so many of those. That one would tell what the address of the nameserver for straightdope.com is. THAT nameserver would then tell what the address of boards.straightdope.com is.

I may have the particulars wrong, but that’s the basics.

4

Hiya,

  1. It’s a mixture of lots of different links. Technically my link at home with a modem to my ISP is part of the Internet. Of course, some links are more equal than others. There are several important backbones that would inconvenience many people if they went down whereas me losing my link would not really inconvenience anybody except me.

  2. A thing called DNS (Domain Name System). This site has details if you want them. As to why some computers are considered authoritative while my home computer isn’t…well…it’s because people generally agree they are. There’s nothing really more special about them than that.