Forum Moderators: phranque
They connect to larger ISPs who eventially or directly attach to what are considered "backbone" providers and links.
Run windows? Open a command prompt and type in "tracert www.webmasterworld.com", it will show you what "hops" your request goes through to get here.
Mac OS X? traceroute www.webmasterworld.com
Linux? /usr/sbin/traceroute www.webmasterworld.com
(Did I get those right?)
It should show you the domain names of some if not all of the routers along the way. Usually you can tell what ISP's things go through by the router names, and sometimes even the physical location.
Traceroute is a tool usually used for network troubleshooting, but it's interesting to see where your packets go even when things are working fine. It also helps in instances like this to see how the network is constructed.