This paper is a product of the Ambient Networks project supported
in part by the European Commission under its Sixth Framework
Program. The views and conclusions contained herein are those
of the authors and should not be interpreted as necessarily representing
the official policies or endorsements, either expressed or
implied, of the Ambient Networks project or the European Commission.
Bengt Ahlgren also partly supported by the Winternet research
program funded by the Swedish Foundation for Strategic
Research.