Your Internet Consultant - The FAQs of Life Online

1.23. Hey, wow! I'm sitting in Eureka and talking to a computer in Finland. Who's paying for the phone call when I connect to some far-off host?

Answered by Mitch Patenaude (mrp@rahul.net), the guy who scored my first Net connection for me.

The answer to this question is a mixture of "nobody" and "a lot of people." To understand why this is so, you need to know a little about the way the Internet is organized.

First, you have to understand that the Internet transmits the information you send by breaking it up into small pieces called packets and sending those packets to the remote machine. The difference between most networks and the Internet is that for most packet-based networks, the machine you are sending information to must be connected to the same network as the computer you are sending it from. Small networks like this are called local area networks (LAN). Internet is a type of wide area network (WAN). WANs typically consist of several LANs hooked together.

When you connect to a host far away, you are not connected by a single phone or data line. The Internet works by connecting lots of little networks with a few big ones. When you communicate with a computer on the other side of the globe, or even just the other end of your state, the information passes through many networks owned and maintained by a variety of organizations.

When you want to communicate with a machine that is not plugged in to your own local network, your computer needs to find a way to get the information to the distant machine. This is like trying to get from an airport in Eureka, California, to one in Helsinki, Finland. There are no direct-connecting flights (that is, no direct network connection from Eureka to Finland. Not surprising.)

So your local network asks its Internet's travel agent (called a router, the machine that connects your local network to the Internet) whether it knows the way to the remote host and how many "hops" it would require to get the information there. (A "hop" is like a stopover at an airport.) One router might find a path from here to there in five hops (Eureka to San Francisco, San Francisco to New York, and so on). Your network then asks for directions from any other routers that are available.

The router that responds with the fewest number of "hops" is given the message to pass along. The network serving as the router does the same thing as your local network, shopping for the shortest route to get your message to its destination. (Your message spends only a few milliseconds at each stopover, a far cry from the endless hours people spend waiting in airports.)

So the information is passed from one network and computer to another until it gets where it's going. Back to the question: the only phone call you're paying for is the one to connect you to your service provider, and your service provider is paying for a connection to some other part of the Internet. Past that, you message uses space on several other networks owned and paid for by many other organizations. You pay a tiny bit, therefore, as does everyone else on the path of your message. Everyone pays, and no one does. Very Zen, don't you think?

Note: And now, the moral of the everybody-pays-nobody-pays technique: the Internet is an incredible communications network that costs billions of dollars and uncounted millions of man hours to maintain each year. One of the great strengths and great weaknesses of the Internet is that it depends on mutual cooperation: the trust that people and organizations have in allowing others all over the world to use their resources. If that trust is abused, the Internet will stop being such an open place and everybody loses.

Using a program called traceroute, I traced the path of a message from San Jose, California, to Finland. It made the journey in 21 hops (this doesn't have to make sense, but it's interesting to look at).

traceroute to tolsun.oulu.fi (130.231.96.16), 30 hops max, 40 byte
packets
 1  sj (192.160.13.201)  3 ms  4 ms  4 ms
 2  barrnet-remote (131.119.73.13)  368 ms  409 ms  453 ms
X (131.119.249.1)  404 ms  515 ms  236 ms
 4  SU-SP.BARRNET.NET (131.119.49.1)  424 ms  357 ms  565 ms
 5  fd-0.enss128.t3.ans.net (192.31.48.244)  797 ms  1415 ms  907 ms
 6  * t3-0.San-Francisco-cnss9.t3.ans.net (140.222.9.1)  2776 ms  1420 ms
 7  mf-0.San-Francisco-cnss8.t3.ans.net (140.222.8.222)  933 ms  142 ms  442
ms
 8  t3-0.Chicago-cnss24.t3.ans.net (140.222.24.1)  281 ms  582 ms  840 ms
 9  * t3-0.Cleveland-cnss40.t3.ans.net (140.222.40.1)  705 ms  922 ms
10  t3-1.New-York-cnss32.t3.ans.net (140.222.32.2)  910 ms  654 ms  578
ms
11  t3-1.Washington-DC-cnss56.t3.ans.net (140.222.56.2)  528 ms  464 ms  599
ms
12  mf-0.Washington-DC-cnss58.t3.ans.net (140.222.56.194)  315 ms  1054 ms
910 ms
13  t3-0.enss145.t3.ans.net (140.222.145.1)  774 ms  1256 ms  1072 ms
14  192.203.229.245 (192.203.229.245)  515 ms  134 ms  113 ms
15  icm-dc-1-H1/0.icp.net (192.157.65.121)  109 ms  241 ms  266 ms
16  192.121.154.233 (192.121.154.233)  925 ms  788 ms  881 ms
17  nord-gw.nordu.net (192.121.154.19)  1031 ms *  813 ms
18  fi-gw.nordu.net (192.36.148.162)  469 ms  532 ms  258 ms
19  ananas-gw.funet.fi (128.214.6.207)  475 ms  748 ms  541 ms
20  oliivi-gw.funet.fi (128.214.254.5)  358 ms  671 ms  656 ms
21  tolsun.oulu.fi (130.231.96.16)  730 ms  424 ms  612 ms
Note: Nets and taxes--If the information is traveling any significant distance in the United States, it will probably travel over a very large and fast network known as the NSFNET. The NSFNET is maintained by the National Science Foundation, which means that it's paid for with your tax dollars, so everybody pays a little. The NSF is slowly backing off from that responsibility. Soon commercial service providers, not the NSF, will maintain that backbone.

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