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Powerful Providers Draw the Line

Large Internet service providers are demanding that small ISPs handle addresses in a way the prefer--or risk excommunication.

by Joel Snyder

"You can't take it with you, but you can always die trying."
--Romeo Julieta, Thoughts on Living

At the end of the 19th century, much of the central European continent was broken up, almost at random, into separate small nations by the great powers of Europe. This was the solution to what was known as the "Eastern Question," and it gave us a new word: balkanization. The consequences of carving up the Balkan Peninsula are now being seen in the bloody and violent civil wars that have wracked the area since the former Soviet Union loosened controls.

Another kind of balkanization is beginning to happen on the Internet. While the consequences could not equal what has happened in Europe, there are lessons to be learned and precautions to be taken. The major Internet Service Providers (ISPs) are putting their collective foot down about IP numbers. If you're part of a small- or medium-size business connected to the Internet, this could affect you.

Some ISPs have said they are going to draw the line: Some networks attached to the Internet will not be able to talk to other networks attached to the Internet. Parts of the Internet are going to be balkanized.

The problem lies in the way traffic is routed around the Net. At the core of the Internet are communications processors called routers, which have to know about every single network connected to the Net. These routers communicate with one another, pass the routing information around, and decide how every Internet packet gets handled. If a network is added in a lab in Caracas, Venezuela, core routers all over the world have to know about it. There are limits to the number of networks these routers can handle.

The first solution to this problem came several years ago with a system called Classless InterDomain Routing (CIDR). With CIDR, groups of networks are handled as a single block, taking up only a single entry. For example, a company with 10 networks but only a single line to the Internet could get a CIDR block of consecutive IP network numbers that takes up much less space than would 10 network numbers.

CIDR has reduced the load on the core Internet routers tremendously, mostly because the ISPs have enthusiastically adopted the idea. When you connect to the Internet, you ask your ISP for IP network numbers. That way, all the customers of a single ISP (and there could be thousands) only take up a small number of entries in the global routing tables. It's a wonderful solution to a difficult problem.

Unfortunately, it's a technical solution, and the Internet is no longer a place where the best technical solutions win. The Internet has become the target of political, legal, and even religious arguments. The benevolent technocracy that ruled the Internet during its childhood is being pushed aside in favor of a more "businesslike" approach.

The Problem

Let's assume you've connected to the Internet via Jan's Internet Service. Jan gives you some IP network numbers out of the CIDR block assigned to her by the Internet Network Information Center (InterNIC). You decide you want to change providers. What happens?

There are two possibilities. Either you take your numbers with you or you don't.

If you don't, you have to go back to every workstation and PC on your network, every router and server, and change the configuration with numbers you get from your new provider. That's not bad if you have 10 computers, but if you have 100 or more you may want to keep your network numbers--if Jan will let you.

Let's say Jan is a kindhearted soul and agrees to let you keep your numbers. In geek-speak, you have just punched a hole in her CIDR block. The ISPs at the core of the Internet don't like this idea. You have created an inefficient block, because now the core routers have to add entries not only for Jan's big block but also for the little piece you took with you. The other ISPs don't like the idea that the core ISPs have decided that certain inefficient blocks won't be entitled to entries in the global routing tables.

You're going to have to renumber, whether you like it or not. Renumbering is painful, expensive, and disruptive. But you have no choice. Small CIDR blocks aren't just an artifact of changing ISPs. You also could have gotten an inefficient block directly from the InterNIC, if you wanted a block but hadn't picked an ISP. The question isn't whether you're punching a hole in a larger block, but whether your block is so small that it's inefficient to carry the routing information.

The ISPs who more or less run the core of the Internet are not particularly sympathetic about this situation. As a technical solution, they'd rather have the entire Internet be renumbered. The routing tables would shrink to a tiny fraction of their current size, and packets would run faster across the core. Of course, the ISPs know this is never going to happen, but they can slow the further growth of the routing tables by limiting the kinds of blocks they'll accept.

Is your company going to be affected? Probably not. There are lots of networks that form the Internet, and this new policy of route rationing is only aimed at those who joined after the CIDR program was put in place.

Real-World Rules

This policy represents the difference between the Internet way of doing things and the real world. In the real world, this sort of dictatorial pronouncement would never be allowed. It may be the right thing to do, the most cost-effective solution, and the fastest way to solve a problem, but that's not the way things work anywhere else.

Look at the United States's toll-free (800) number. It used to be that the long-distance companies broke up the toll-free numbers by exchanges--the first three digits. If you wanted a toll-free number starting with 236, you'd find out that Schneider Communications had that block and you would ask the company for a number. The problem was that if you didn't like the deal you were getting from Schneider, you didn't have a choice, because if you wanted to jump to another company, say AT&T, you'd have to get a new number.

So, in its infinite wisdom, the U.S. government told the telecommunications industry that it would have to let people take their toll-free numbers to any carrier they wanted. And the telecommunications industry spent tens of millions of dollars installing equipment and switches and databases and procedures to make this happen.

You can now take your toll-free number with you--for a price. Now everyone pays more for toll-free service. It's a fraction of a piece of a percent, but it's in there.

What would happen if it were decided, in the real world, that the Internet folks couldn't be allowed to balkanize the Net? We know that the problem can be solved--and probably for somewhat less money than it took to completely open up 800-number portability. After all, you can always throw lots of hardware and software at this kind of problem and make it go away.

But that means everyone on the Internet would end up paying a little more for a small number of organizations not to be inconvenienced. In the meantime, the entire Internet will become both more complex, more expensive, and more susceptible to failure.

So don't run off shouting about how the technocratic dictators of the world shouldn't be allowed to tell you what to do. Think about it for a while. You have two choices. You can either have the Internet do what it does best, and what has made it so valuable in the first place, which is to take the best technical solution possible. Or you can have the Internet change the way it operates to fit the mold of the real world. What's your choice? *IW*

Joel Snyder is a senior partner at Opus One in Tucson, Ariz.

Reprinted from Internet World magazine Vol. 7 No. 1, (c) 1996 Mecklermedia Corporation. All rights reserved.