WASHINGTON — Next month, world diplomats will travel to Tunisia to tackle a topic so dense that it normally clears a room in seconds: how the Internet is governed.

But the United Nations-sponsored World Summit on the Information Society could be the scene of an international brawl, with some claiming that the core freedoms of the global network are at risk. The battle centers on how much control the United States will continue to have in overseeing the Internet's plumbing.

This sounds like geeky stuff, but it matters for everyday users. The technical rules for how networks and computers find and recognize each other can determine how freely and securely information can be retrieved and sent.

These matters are the province of the nonprofit Internet Corporation for Assigned Names and Numbers (ICANN), under a contract with the Commerce Department that expires next year.

The Commerce Department exercises its contractual oversight lightly, adopting the position that government should be involved with Internet governance as little as possible. It has not overruled any ICANN decisions.

Several other countries, particularly in the developing world, object to continuing U.S. supremacy. As the Internet penetrates deeper into societies around the globe, many nations want the international community to supplant the United States as primary overseer. The United States suspects that some of these governments want to try to control the Internet to stifle free expression and preserve dictatorial control.

ICANN coordinates key technical elements of the Internet that enable computers worldwide to communicate with each other. Most notably, it manages the domain-name system (.com, .edu, etc.) so that there's a universal standard of finding and reaching valid addresses. The organization, which has offices in Marina del Ray, Calif., and in Brussels, is governed by a board with members from around the world.

The argument over the Internet's governance has been simmering for some time, and several proposals have been put forth by a U.N. working group for more international oversight, through the United Nations or other entities. Countries such as Iran, China, Saudi Arabia and Brazil have been especially vocal, mirroring other splits in the United Nations over a variety of issues, including the war in Iraq.

But things turned red hot late last month when the European Union infuriated the United States by endorsing the idea of international authority. Attempting to strike a pose between the United States and countries that want a new Internet governing body, the EU said an international "forum" should be created to set policy principles for ICANN and adjudicate complaints.

Martin Selmayr, spokesman for the EU Directorate on Information Society and Media, insisted this week that there is no major split with the United States on the issue.

"We believe in freedom of speech and the freedom of the Internet," he said. "No new organizations need to be set up. ... We're not asking for enhancing government's role" in the operations of the Internet.

But, he said, "The EU is proposing moving from unilateralism to multilateralism in Internet governance. Public policy principles ... issued in the future should be discussed internationally."

The United States is having none of it.

"When the EU's proposal was read, it was interesting how quickly it was endorsed in large part by countries such as Cuba, Iran, Saudi Arabia and others who have been very clear that they do not believe" in principles of free expression, said David Gross, coordinator of International Communications and Information Policy for the State Department.

Gross said the United States would not accept any other entity taking on oversight of ICANN, no matter what may happen at the conference in Tunisia.

"We are firm in our position," he said. "This is not a negotiation."

Gross said the U.S. goal is to keep all governments and politics out of the Internet's evolution and preserve free-market development.