Mobile IP (RFC 2002) is a proposed standard that builds
on the Internet Protocol by making mobility transparent to applications
and higher-level protocols such as TCP. It provides mobility support
to the Network Layer of the TCP/IP stack defined over the 802.11b
WLAN standard.
Technology
A network connection
between two hosts is defined by the tuple of source IP address,
source port and destination IP address, destination port. Any
changes to these could lead to a termination of the connection.
An IP address can be divided into network part and a host part.
The network part of the IP address defines the network to which
the host is a part of. This is called the home network. A mobile
node, like any other host is assigned an IP address by the home
network. When the mobile node moves out of range of the home
network, it is said to have moved into a foreign network. The
IP address that was assigned to the mobile node in the home
network is no longer reachable from the home network and it
is not valid in the foreign network. Mobile IP defines two modules,
a home agent and foreign agent which will ensure that mobile
node can still remain connected to the network without a change
in its IP address. It enables this to happen by introducing
another IP address called the “care-of-address”. When the mobile
node moves out of range of the home network, it registers a
“care-of-address” with the home agent via the foreign agent.
Any packet that is destined for the mobile node will first reach
the home network. The home agent will tunnel the packet to the
“care-of-address”. The packet is de-encapsulated at the end
of tunnel by the “care-of-address” and then forwarded to the
mobile node.
Architecture
There are basically five components
in the Mobile IP architecture:
Framework
comes here
Home agent
This is the term used to define the module in the home network
that will ensure the network connectivity of the mobile node
irrespective of the location of the mobile node.
Foreign agent
This is the term used to define the module in the foreign network
that will interact with the home agent to deliver packets intended
to the mobile node.
Mobile Node
This is the term used to define any node that is connected
to a network and that is mobile i.e., it need not have wired
connectivity to remain connected to the network.
Home Network
This is the network of which the mobile node is originally a
part. The mobile node is assigned an IP address by the home
network.
Foreign Network
This is the term used to define all other networks apart from
the home network. When the mobile node moves out of range of
the home network, it is said to have entered a foreign network.
The home network and foreign network
boundaries are decidedby factors such as signal strength etc.
Usage Scenarios
Mobile IP can be used in all devices
which have an IP stack and some support for mobility. For example:
mobile phones with the GPRS stack, laptops with hardware supporting
802.11b, Bluetooth™ enabled devices etc.
MindTree’s Solution
MindTree has implemented the following
components which are available for license.
