HP 6125XLG Configuration Manual page 166

4. If the destination address of the IPv6 packet is itself, Device B forwards it to the upper-layer
protocol. If not, Device B forwards it according to the routing table.
Tunnel modes
IPv6 over IPv4 tunnels include manually configured tunnels and automatic tunnels, depending on how
the IPv4 address of the tunnel destination is acquired.
Manually configured tunnel—The destination IPv4 address of the tunnel cannot be automatically
•
acquired from the destination IPv6 address of an IPv6 packet at the tunnel source, and must be
manually configured.
• Automatic tunnel—The destination IPv4 address of the tunnel can be automatically acquired from
the destination IPv6 address (with an IPv4 address embedded) of an IPv6 packet at the tunnel
source.
According to the way an IPv6 packet is encapsulated, IPv6 over IPv4 tunnels are divided into the
following modes.
Table 10 IPv6 over IPv4 tunnel modes and key parameters
Tunnel type
Manually
configured tunnel
Automatic tunnel
IPv6 over IPv4 manual tunneling—A point-to-point link and its source and destination IPv4
•
addresses are manually configured. You can establish an IPv6 over IPv4 manual tunnel to connect
isolated IPv6 networks over an IPv4 network, or connect an IPv6 network to an IPv4/IPv6 dual-stack
host over an IPv4 network.
6to4 tunneling—A point-to-multipoint automatic tunnel. It is used to connect multiple isolated IPv6
•
networks over an IPv4 network. The destination IPv4 address of a 6to4 tunnel is embedded in the
destination 6to4 address of packets. This mechanism enables the device to automatically get the
tunnel destination address, simplifying tunnel establishment.
The 6to4 address format is 2002:abcd:efgh:subnet number::interface ID/48, where 2002 is the
fixed IPv6 address prefix, and abcd:efgh represents a 32-bit globally unique IPv4 address in
hexadecimal notation. For example, 1.1.1.1 can be represented by 0101:0101. The IPv4
address identifies a 6to4 network (an IPv6 network where all hosts use 6to4 addresses). The
Tunnel mode
IPv6 over IPv4 manual
tunneling
6to4 tunneling
ISATAP tunneling
Tunnel source/destination
address
The source and destination
IPv4 addresses are manually
configured.
The source IPv4 address is
manually configured. The
destination IPv4 address is
automatically obtained.
The source IPv4 address is
manually configured. The
destination IPv4 address is
automatically obtained.
158
Destination IPv6 address
format
Ordinary IPv6 address.
6to4 address, in the format of
2002:IPv4-destination-addres
s::/48, where the
IPv4-destination-address is the
IPv4 address of the tunnel
destination.
ISATAP address, in the format
of
Prefix:0:5EFE:IPv4-destinatio
n-address/64 where the
IPv4-destination-address is the
IPv4 address of the tunnel
destination.