Transport Optional Upgrade Release (TOUR) 2.0 Release Notes (April 2004)

Transport Optional Upgrade Release (TOUR) 2.0 Release Notes

What Is in This Version

Home Agent

Home Agents are nodes or routers that provide mobility services to Mobile Nodes from their

home network. During Mobile IPv6 basic operation, when a Mobile Node is attached to a

foreign network— any network other than its home network—it gets a temporary Care-of

Address identifying its current location. The Home Agent intercepts data packets sent to the

Mobile Node’s Home Address and transparently routes them to the Mobile Node’s current

Care-of Address on the foreign network.

Corespondent Node

Correspondent Nodes are any IPv6 node communicating or corresponding with a Mobile

Node, for example Web servers providing location-sensitive resources to the Mobile Nodes. In

most cases, the Mobile Node and Correspondent Node communicate using Route

Optimization. Mobile IPv6 basic operation is only used in the initial communication, when the

Correspondent Node does not have information about the Mobile Node’s Care-of Address, and

in cases where the Correspondent Node does not support Mobile IPv6 Route Optimization

(such as IPv4 systems).

Route Optimization

In most cases, the Mobile Node and Correspondent Node communicate using Route

Optimization, which improves data transmission rates between the two nodes. With Route

Optimization, the Mobile Node and Correspondent Node communicate directly with each

other and bypass the Home Agent. The Correspondent Node sends packets directly to the

Mobile Node’s Care-of Address, and the Mobile Node sends packets directly to the

Correspondent Node.

Return Routability Procedure

When Mobile Nodes receive data-packets from Correspondent Nodes routed through the

Home Agent, it indicates the Correspondent Node does not have binding information with the

Mobile Node’s current Care-of Address. In this case, the Mobile Node can use the Return

Routability Procedure to establish Route Optimization and verify the Correspondent Node

can contact the Mobile Node using both its Home Address and Care-of Address.

During the Return Routability Procedure the Mobile Node sends a Binding Update message

to the Correspondent Node with its current Care-of Address. To prevent attackers from

sending false Binding Update messages, the Binding Update is authenticated using a

cryptographic signature.