Introducing HP-UX Mobile IPv6

2. Why HP-UX Mobile IPv6 is the Answer

HP-UX Mobile IPv6 is the answer to today’s—and tomorrow’s—mobility demands.

The free-of-charge and IETF standards-based HP-UX Mobile IPv6 allows Mobile Nodes, such as

laptops, PDAs, and cell phones, to remain reachable and constantly connected while roaming and

attaching to the network from different locations.

Without Mobile IPv6, Mobile Nodes cannot use a single, fixed IPv6 address while they roam. Instead,

each time a Mobile Node moves and changes network attachment points, it must manually re-

configure a new IP address and default router based on its current location—temporarily losing its

network connections and ability to communicate in the process.

HP-UX Mobile IPv6 handles mobility management at the IP layer—the only common layer for

applications in IP networks—and therefore mobility is transparent to the layers above the IP layer.

Additionally, HP-UX Mobile IPv6 provides mobility support without the difficulties of managing NAT,

DNS mappings, and pre-configured security associations.

HP-UX Mobile IPv6 employs two IPv6 addressing concepts:

• Home Addresses

• Care-of Address

Each Mobile Node sends and receives IP data packets using a single, fixed IPv6 address—known as

its Home Address—for an extended period regardless of its location. The Mobile Node’s Home

Address is an IPv6 unicast routable (global) address with a network prefix on the Mobile Node’s Home

Network.

When a Mobile Node is attached to a Foreign Network (any network other than its Home Network) it

gets a temporary Care-of Address on the Foreign Network. The Care-of Address is an IPv6 unicast

global address with the network prefix of the Foreign Network. The Mobile Node can get this address

using IPv6 stateless auto-configuration, or by using a stateful configuration method such as DHCP.

2.1 The Mobile IPv6 Protocol

The Mobile IPv6 protocol is tightly-coupled with the IPv6 protocol, thereby taking advantage of several

IPv6 mechanisms, and expanding several more. The following is a brief list of the IPv6 protocol

mechanisms the Mobile IPv6 protocol utilizes:

• expanded IPv6 Mobility Extension Headers for Mobile IPv6 signaling messages, such as Binding

Updates, Home Address and Care-of Address Test Inits and Tests, and Binding Requests

• expanded IPv6 Destination Option to include a Mobile Node’s Home Address

• new Type 2 Routing Header for Route Optimization

• new ICMPv6 messages for Home Agent Discovery Requests and Replies, and Prefix Solicitations and