Mobile IPv6 A.01.00 Administrator's Guide

Chapter 1
Introducing HP-UX Mobile IPv6
Overview
3
Comparison of Mobile IPv4–Mobile IPv6
The following information might be helpful if you are migrating from Mobile IPv4 to Mobile IPv6, or if you
understand Mobile IPv4 and want to preview Mobile IPv6 by comparing the two distinct technologies. The
following is a list of the major differences between Mobile IPv4 and Mobile IPv6 concepts; refer to IETF
documentation for complete information.
• IPv4 addresses are 32 bits long—IPv6 addresses are 128 bits long, which almost surely eliminates the
possibility of using-up all the addresses in IPv6.
• Mobile IPv4 uses tunnel routing to deliver data-packets to Mobile Nodes—Mobile IPv6 uses tunnel
routing and source routing with IPv6 Type 2 routing headers.
• Mobile IPv4 deploys Foreign Agents for Mobile Node movement detection and to decapsulate data-packets
addressed to the Mobile Node’s Care-of Address—Mobile IPv6 Mobile Nodes decapsulate messages sent to
its Care-of Address itself and uses IPv6 Router Advertisements for movement detection, thereby
eliminating the need for Foreign Agents.
• Mobile IPv4 uses Agent Discovery for Movement Detection—Mobile IPv6 uses IPv6 Router Discovery.
• Mobile IPv4 Route Optimization is an extension to the protocol, not part of the base RFC; requires
pre-configured and static security associations; and, was difficult to operate with ingress-filtering
routers—Mobile IPv6 Route Optimization is a fundamental part included in the protocol; provides
integrated Return Routability to dynamically secure Route Optimization; and, operates effectively with
ingress-filtering routers.
• Mobile IPv4 reverse tunneling is an extension to the protocol—Mobile IPv6 bi-directional tunneling is
part of the core protocol.
• Mobile IPv4 uses one Home Address—Mobile IPv6 uses a globally routable Home Address and a link-local
Home Address.
• Mobile IPv4 uses ARP to determine the link layer address of neighbors—Mobile IPv6 uses IPv6 Neighbor
Discovery and is de-coupled from any given link layer.
• Mobile IPv4 Dynamic Home Agent Address Discovery uses a directed broadcast approach and returns
separate replies from each Home Agent to the Mobile Node—Mobile IPv6 Dynamic Home Agent Address
Discovery uses anycast addressing and returns a single reply to the Mobile Node.
• Mobile IPv4 Mobile Nodes can obtain Care-of Addresses via Agent Discovery, DHCP, and manual
configuration—Mobile IPv6 Mobile Nodes can obtain Care-of Addresses via Stateless Address
Auto-configuration, DHCP, and manual configuration
• Mobile IPv4 uses Foreign Agent Care-of Address and a co-located Care-of Address—Mobile IPv6 Care-of
Addresses are all co-located.