July 2003

The End of End-to-End?

Continued from page 1

By Simson Garfinkel

On the Internet, end-to-end promotes competition by making it easy for users to switch from one network provider to another. If I don't like the service I'm getting from my broadband digital subscriber line (DSL) connection, I can swap it out for a high-speed cable modem. Sure, my computer's Internet Protocol address will change. But thanks to end-to-end, that address really doesn't matter.

End-to-end is such a basic principle that just about any tinkering with it is bound to cause problems. Consider those Internet service providers that have toyed with blocking unsolicited junk mail: a few customers wanted their spam and resented any e-mail filtering by the provider. Other customers discovered that some legitimate e-mail was accidentally being filtered out along with the tasteless promotions for Viagra and cheap refinancing (see "Spam Wars").

Another way to break end-to-end is to modify packets so that they go somewhere other than their originally intended destinations. That's what the government of China did earlier this year when it ordered the country's Internet service providers to replace Google's home page with a China-based search engine. Packets were intercepted and rewritten on the fly. China was thus forcing the service providers to violate the end-to-end principle: it shouldn't be the job of the network to reroute your packets to a competing Web server or block them because the content is deemed illegal.

Nevertheless, most Internet service providers would like to be able to violate end-to-end as they see fit-blocking spam, filtering out viruses, and perhaps even suppressing advertisements. They would like to make customers dependent on these "enhanced" network services so that it would be harder than ever to switch providers. Then they might start dabbling in other end-to-end infringements, like rewriting the results of Google queries, inserting advertisements directly into your e-mail, and even mining your Web-browsing habits so that they can more easily target advertisements.

Whenever you hear a company bragging about the great services it can offer directly in its network, understand that it is trying to kill end-to-end. Personally, I'd rather have a dumb network, a pair of smart endpoints, and a future.