Location update techniques are described. A dormant mobile node updates
its location information by sending a first message over a wireless link
to an access node. The access node generates a second update message in
response to the first message. The second message includes a mobile node
identifier and, in some embodiments is directed to the mobile node. The
second message is received by a tracking agent, which updates location
information corresponding to the mobile node. In the case where second
message is an IP message and is routed to the mobile node using Mobile
IP, a Mobile IP home agent routes the second message to the mobile node's
last point of network attachment where the tracking agent is located and
intercepts the message. The tracking agent may send a response message to
the access node sending the second message.