IPv6 addresses are topologically correct, therefore nodes
attached to the same physical network or LAN segment must have the
same IPv6 network address prefix. Mobile IPv6 provides transparent
routing of IP data-packets to a mobile IP device or node, such as
a portable computer, regardless of the mobile node’s point of
attachment to the network. Mobile IPv6 allows a mobile node to move
from one wireless access point or base station with no disruption
in network connectivity.
The
main components of Mobile IPv6 operation are:
Home Agent (for basic operation)
Mobile
Node and Home Address |
 |
With
Mobile IPv6, a client IP node, or Mobile Node (MN),
can change network attachment points and use a single, fixed IPv6
address for extended periods of time, regardless of its current
attachment point. This address is known as the Mobile Node’s home
address. Without Mobile IPv6,
Mobile Nodes cannot use a single, fixed IPv6 address while they
roam. Instead, each time a Mobile Node moves and changes network attachment
points, it must manually re-configure a new IP address and default
router based on its current location—temporarily losing
its network connections and ability to communicate in the process.
The Mobile Node’s home address is a unicast routable
(global) address, with the network prefix of the Mobile Node’s
home network. The Mobile Node’s home
network is the network that administers the Mobile Node, and
is typically the network to which the Mobile Node is normally attached.
Care-of
Address |
|
When a Mobile Node is attached to a foreign
network (a network other than its home network),
it gets a temporary Care-of Address (COA)
on the foreign network. The Care-of Address is an IPv6 unicast global address
with the network prefix of the foreign network. The Mobile Node
can get this address using IPv6 stateless auto-configuration, or
by using a stateful configuration method (such as DHCP).
Route Optimization |
|
In addition to basic operation, Mobile IPv6 can operate using Route Optimization.
Route Optimization improves data transmission rates between the
Correspondent Node and Mobile Node. With Route Optimization, the
Mobile Node and Correspondent Node communicate directly with each
other and bypass the Home Agent. Route Optimization is especially
beneficial when the Mobile Node and Correspondent Node are in the
same network.
The Correspondent
Node sends data-packets directly to the Mobile Node’s Care-of
Address, as show in Figure 1-3 “Correspondent Node to Mobile Node in Route
Optimization”.
The Mobile Node sends data-packets directly to the Correspondent
Node, as shown in Figure 1-4 “Mobile Node to Correspondent Node in Route
Optimization”.
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