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
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.
Depending on which network the mobile client is
currently visiting; its point of attachment Foreign Agent)
may change. At each point of attachment, Mobile IP
either requires the availability of a standalone Foreign
Agent or the usage of a Co-located care-of address in
the mobile client itself.
The concept of "Mobility" or "packet data mobility",
means different things depending on what
the word is used within. In a wireless or fixed
environment, there are many different ways of
implementing partial or full mobility and roaming services.
The most common ways of implementing mobility
(discrete mobility or IP roaming service) support
in today's IP networking environments includes
simple "PPP dial-up" as well as company internal
mobility solutions implemented by means of renewal
of IP address at each new point of attachment.
The most commonly deployed way of supporting
remote access users in today's Internet is to utilize
the public telephone network (fixed or mobile) and
to use the PPP dial-up functionality.
satya prakash tiwari
b.tech(c.s.e)
No comments:
Post a Comment