IPv6 Mobility Support

Because routing is based on the subnet prefix in a packet's destination IP address, packets destined for a mobile node, host or router, do not reach the node when unattached to its home link (the link where its home IPv6 subnet prefix exists). In order to continue communication, regardless of a node's movement, a mobile node could change its IP address each time it moves to a new link. However, the mobile node would not maintain transport and higher-layer connections when it changes location. Consequently, IPv6 mobility support is particularly important when recognizing that mobile computers might account for a significant population of the Internet in the future.

IPv6 mobility support solves this problem. It enables a mobile node to move from one link to another without changing the mobile node's IP address. It accomplishes this through the assignment of an IP address to the mobile node within its home subnet prefix on its home link. This is known as the node's home address.

Thus, packets routed to the mobile node's home address reach their destination regardless of the mobile node's current point of attachment to the Internet. The mobile node can continue to communicate with other nodes (stationary or mobile) after moving to a new link.

Though IPv6 mobility support solves the problem of transparently routing packets to and from mobile nodes while away from home, it does not solve all the problems related to the use of mobile computers or wireless networks. In particular, it does not attempt to solve the following problems:

• Handling links with partial reachability, such as typical wireless networks (though a movement detection procedure addresses some aspect)

• Access control on a link being visited by a mobile node