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.