HP-UX IPv6 Transport Administrator's Guide for TOUR 1.0

IPv6 Software and Interface Technology
Migrating from IPv4 to IPv6
Chapter 768
Migrating from IPv4 to IPv6
To successfully migrate to IPv6, maintain compatibility with the large
installed base of IPv4 hosts and routers. Staying compatible with IPv4
when deploying IPv6 eases the task of moving the Internet to IPv6.
HP-UX 11i IPv6, bundled as part of TOUR 1.0, supports three of the
many transition mechanisms recommended by the IETF:
• Dual-Stack
• Automatic and Configured Tunneling IPv6 traffic through IPv4
networks
• “6to4” Connection of IPv6 Domains via IPv4 Clouds (RFC 3056).
Note that only host functionality is supported by HP-UX 11i IPv6
bundled as part of TOUR 1.0.
Dual Stack Dual Stack nodes support both IPv6 and IPv4 functionality. HP-UX 11i
IPv6 bundled as part of TOUR 1.0 supports dual stack. IPv6 applications
can coexist with IPv4 applications.
Tunneling Tunneling encapsulates IPv6 packets within IPv4 packets. IPv6
transmission across the IPv4 Internet is transparent.
Tunneling
IPv6 tunneling enables IPv6 hosts and routers to connect with other
IPv6 hosts and routers over the existing IPv4 Internet. IPv6 tunneling
encapsulates IPv6 datagrams within IPv4 packets. The encapsulated
packets travel across an IPv4 Internet until they reach their destination
host or router. The IPv6-aware host or router decapsulates the IPv6
datagrams, forwarding them as needed. IPv6 tunneling eases IPv6
deployment by maintaining compatibility with the large existing base of
IPv4 hosts and routers.
IPv6/IPv4 hosts and routers can tunnel IPv6 datagrams over regions of
IPv4 routing topology by encapsulating them within IPv4 packets.
Tunneling can be used in a variety of ways:
Router-to-Router IPv6/IPv4 routers interconnected by an IPv4 infrastructure can tunnel
IPv6 packets between themselves. In this case, the tunnel spans one
segment of the end-to-end path that the IPv6 packet takes.