Mobile IPv6 A.01.00 Administrator's Guide

Chapter 1

Introducing HP-UX Mobile IPv6

Establishing Basic Operation

Mobile Node Acquires Care-of Address

When the Mobile Node attaches to a new foreign network, it gets a new Care-of Address using a stateless

(IPv6 stateless autoconﬁguration) or stateful (such as DHCPv6) method. The Care-of Address has the

network preﬁx of the foreign network.

Mobile Node Sends Binding Update to Home Agent

After the Mobile Node determines its Care-of Address, it sends a Binding Update message to its Home

Agent. The Binding Update message binds, or registers, the Mobile Node’s Care-of Address with the Mobile

Node’s Home Address. The Binding Update message is encrypted and authenticated using IPSec.

When the Home Agent receives the Binding Update message, the IPSec module on the Home Agent

authenticates the message. The Home Agent sends a Binding Acknowledgement to the Mobile Node. The

Binding Acknowledgement is a message to the Mobile Node, in response to it’s Binding Update,

acknowledging the Mobile Node’s Binding Update and indicating whether it was accepted or rejected. The

Binding Acknowledgement also includes a ﬁxed lifetime for the registration.

The Home Agent keeps a record of Mobile Node’s home addresses and current Care-of Addresses in a

binding cache. The Home Agent adds or updates the binding between the Mobile Node’s home address with

its current Care-of Address to this cache.

Home Agent Sends Neighbor Advertisements for the Mobile Node

After the Mobile Node registers its Care-of Address with its Home Agent, the Home Agent sends a Neighbor

Advertisement message on behalf of the Mobile Node to the all-nodes multicast address for the local link. This

Neighbor Advertisement binds the Home Agent’s link-level address to the Mobile Node’s home (IP) address.

The other nodes and routers on the local network will update their Neighbor Caches to link the Home Agent’s

link-level address with the Mobile Node’s home address. Data-packets addressed to the Mobile Node’s home

address will be sent to the Home Agent’s link-level address, and processed by the Home Agent.

The Home Agent will also respond to any Neighbor Solicitation requests for the Mobile Node’s home address

by sending Neighbor Advertisements with its link-level address and the Mobile Node’s home IP address.