HP-UX IPv6 Transport Administrator's Guide for TOUR 2.0 (April 2004, rev 2)

IPv6 Software and Interface Technology
Migrating from IPv4 to IPv6
Chapter 7 73
Tunneling can be used in a variety of ways:
• Router-to-Router: IPv6/IPv4 dual stack 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.
• Host-to-Router: IPv6/IPv4 dual stack hosts can tunnel IPv6
packets to an intermediary IPv6/IPv4 router that is reachable over
an IPv4 infrastructure. This type of tunnel spans the first segment of
the packet’s end-to-end path.
• Host-to-Host: IPv6/IPv4 (dual stack hosts that are interconnected
by an IPv4 infrastructure can tunnel IPv6 packets between
themselves. In this case, the tunnel spans the entire end-to-end path
that the packet takes.
• Router-to-Host: IPv6/IPv4 routers can tunnel IPv6 packets to their
final destination IPv6/IPv4 host. This tunnel spans only the last
segment of the end-to-end path.
Starting with TOUR2.0, the HP-UX 11i v2 IPv6/IPv4 dual stack node
can perform the role of the router. It can also continue to perform the role
of the host, as it has since IPv6NCF11i.
Configured and Automatic Tunneling
Two tunneling techniques are specified in RFC 2893: configured and
automatic. The two techniques differ primarily in how the tunnel
end-point is determined.
Configured Tunnels are point-to-point tunnels; tunnel configuration
must be done on both ends of the tunnel. The tunnel endpoint is
determined from the configuration information.
RFC 2893 specifies tunnels as IPv6 interfaces and requires them to be
configured with at least (on primary interfaces) link-local addresses. To
conform to RFC 2893, tunnels are implemented as IPv6
pseudo-interfaces.
In TOUR 2.0 tunnels can be configured (ephemerally) using ifconfig
and permanently by editing /etc/rc.config.d/netconf-ipv6. In
general, the following tunnel parameters are relevant in TOUR 2.0: