Because of the widespread availability of high speed access, services which have been spoken about for a long time (IP telephony, videoconferencing ) appear today to be possible on a huge scale. Some of these services are available on both telephone and computer networks using the same protocols.
Besides as terminals are more and more frequently mobile, it is important to allow these services to be used by nomad users or cell-phone users. This may be done by integrating management of this mobility directly into the protocol operating the services or by rendering the mobility transparent to applications through Mobile IP.