Mobile IP management messages are sent using: UDP on port# 434              (See bottom of page 4 of click here)

Binding Update message = a IP message that is used for notification of a mobile node's current mobility binding. See: click here

0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 18 |A|I|M|G| Rsv | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mobile Node Home Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Care-of Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Identification + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Suppose the mobile host 10.0.0.4 just received a tunneled message: The mobile host will send a binding update message : ( 10.0.0.4, 12.0.0.1, time-duration ) to the sender: The binding update message will update the binding cache to:

The host 11.0.0.7 will now use a direct route to send IP packets to the mobile host 10.0.0.4:

After the binding update message is processed, the mobile host can move to another network

Result:

Messages sent with the binding cache information will: not be delivered to the mobile !!! (I.e.: lost !!!)

Example:

The binding cache entries has a expiration time

Note:

After the binding cache entry expires: The IP packet will first be sent to the home agent The home agent will tunnel the IP packet to the mobile host When the mobile host receives the IP packet, the mobile host can send a new binding update to the source node