While
Internet technologies largely succeed in overcoming the barriers of time and distance,
existing Internet technologies have yet to fully accommodate the increasing mobile
computer usage. A promising technology used to eliminate this current barrier
is Mobile IP. The emerging 3G mobile networks are set to make a huge difference
to the international business community. 3G networks will provide sufficient bandwidth
to run most of the business computer applications while still providing a reasonable
user experience. However, 3G
networks are not based on only one standard, but a set of radio technology standards
such as cdma2000, EDGE and WCDMA. It is easy to foresee that the mobile user from
time to time also would like to connect to fixed broadband networks, wireless
LANs and, mixtures of new technologies such as Bluetooth associated to e.g. cable
TV and DSL access points.In this
light, a common macro mobility management framework is required in order to allow
mobile users to roam between different access networks with little or no manual
intervention. (Micro mobility issues such as radio specific mobility enhancements
are supposed to be handled within the specific radio technology.) IETF has created
the Mobile IP standard for this purpose.
Mobile
IP is different compared to other efforts for doing mobility management in the
sense that it is not tied to one specific access technology. In earlier mobile
cellular standards, such as GSM, the radio resource and mobility management was
integrated vertically into one system. The same is also true for mobile packet
data standards such as CDPD, Cellular Digital Packet Data and the internal packet
data mobility protocol (GTP/MAP) of GPRS/UMTS networks. This vertical mobility
management property is also inherent for the increasingly popular 802.11 Wireless
LAN standard.Mobile IP can be
seen as the least common mobility denominator - providing seamless macro mobility
solutions among the diversity of accesses. Mobile IP is defining a Home Agent
as an anchor point with which the mobile client always has a relationship, and
a Foreign Agent, which acts as the local tunnel-endpoint at the access network
where the mobile client is visiting.
