Specifications

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Cisco Aironet Access Point Software Configuration Guide
OL-0657-07
Chapter 6 Configuring Proxy Mobile IP
Proxy Mobile IP
the registration request to the visiting client’s home agent through the foreign
agent. The foreign agent checks the validity of the registration request, which
includes verifying that the requested lifetime does not exceed its limitations and
that the requested tunnel encapsulation is available. If the registration request is
valid, the foreign agent relays the request to the home agent.
The home agent checks the validity of the registration request, which includes
authentication of the visiting client. If the registration request is valid, the home
agent creates a mobility binding (an association of the visiting client with its
care-of address), a tunnel to the care-of address, and a routing entry for
forwarding packets to the home address through the tunnel.
The home agent then sends a registration reply to the visiting client through the
foreign agent (because the registration request was received through the foreign
agent). The foreign agent verifies the validity of the registration reply, including
ensuring that an associated registration request exists in its pending list. If the
registration reply is valid, the foreign agent adds the visiting client to its visitor
list, establishes a tunnel to the home agent, and creates a routing entry for
forwarding packets to the home address. It then relays the registration reply to the
visiting client.
Finally, the access point checks the validity of the registration reply. If the
registration reply specifies that the registration is accepted, the access point is
able to confirm that the mobility agents are aware of the visiting client's roaming.
Subsequently, the access point intercepts all packets from the visiting client and
sends them to the foreign agent.
The access point reregisters on behalf of the visiting client before its registration
lifetime expires. The home agent and foreign agent update their mobility binding
and visitor entry, respectively, during reregistration.
A successful Mobile IP registration by the access point on behalf of the visiting
client sets up the routing mechanism for transporting packets to and from the
visiting client as it roams.
Tunneling
The visiting client sends packets using its home IP address, effectively
maintaining the appearance that it is always on its home network. Even while the
visiting client is roaming on foreign networks, its movements are transparent to
correspondent nodes (other devices with which the visiting client communicates).