Methods and apparatus for registering a mobile device such as a mobile
node or mobile router with a Home Agent in an asymmetric link
environment. A Foreign Agent associates each of one or more interfaces of
the Foreign Agent with a different care-of address. An agent
advertisement including the care-of address for the one or more
interfaces of the Foreign Agent is then sent via one or more uplinks. A
registration request is received via a downlink router. The registration
request identifies a care-of address associated with one of the one or
more interfaces of the Foreign Agent. One of the interfaces identified by
the care-of address is ascertained, thereby identifying the interface to
which the mobile device has roamed. The registration request is forwarded
to the Home Agent. A registration reply is received from the Home Agent.
The registration reply is then forwarded to the mobile device via the
ascertained interface.