Roaming costs have been history since October 2006 - at least for One Network customers in eastern Africa. The world's first border-free network, operated by Celtel, lets Kenyan, Tanzanian and Ugandan customers communicate freely across borders.

With One Network, customers don't have to pay roaming call surcharges or pay to receive incoming calls while abroad. Customers are only charged a local fee when using their phones within Kenya, Tanzania and Uganda.

Lars Stuber, Ericsson's key account manager for Celtel, says: "The upsides of additional calls being made clearly outweigh the downsides of reductions in roaming fees. Of course there are costs for the operator attached to it, at least if you look at it from an orthodox financial perspective."

To implement One Network in the east African market, Celtel used Ericsson network equipment to its maximum. The original networks, built up over five years, were replaced by Ericsson in just four months each.

Hans Piet, Ericsson's customer solutions manager working with Celtel, says: "Ericsson and Celtel have developed a very strong partnership over the past five years and Ericsson implemented all Celtel's network swap-out operations in the region."

Despite only being in place for less than year, One Network is already beginning to change the way consumers use their mobile phones. One Network has an estimated 5-7 percent market share in the region. Minutes of usage increased by approximately 10 percent, which contributes to Celtel's average revenue per user of USD 9-10 for Kenya.

"I think people all over the world have been reluctant to use their mobile phone when traveling," Stuber says. "What we are beginning to see with One Network is a more 'homelike' use of cellular phones abroad. There is a positive spin-off effect as well - Celtel's regional competitors are also beginning to offer border-free calls without extra charges."

As the European Union is about to introduce legally binding maximum tariffs for roaming costs in its 27 member states, Celtel's One Network initiative is an example of a free market price adjustment mechanism.

"I think that One Network clearly highlights operators' ability to deal with this without policy makers getting involved," Stuber says.

And the initiative will not stop at Kenya, Uganda and Tanzania. "Celtel has a vision of bringing One Network to the entire African continent," Stuber says. "One Network in east Africa is just the start."