H3C Technologies H3C S12500 Series Switches - Manual (Page 169)

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physical interface of the tunnel. In the IPv4 header, the source IPv4 address is the IPv4 address of
the tunnel source, and the destination IPv4 address is the IPv4 address of the tunnel destination.
3. Upon receiving the packet, Device B de-encapsulates the packet.
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.
410B
Tunnel types
IPv6 over IPv4 tunnels fall into 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 Tunnel mode
Tunnel source/destination
address
Tunnel interface
address
Manually
configured tunnel IPv6 over IPv4 manual
tunneling
The source and destination IPv4
addresses are manually
configured.
IPv6 address
Automatic tunnel
Automatic
IPv4-compatible IPv6
tunneling
The source IPv4 address is
manually configured. The
destination IPv4 address is
automatically obtained.
IPv4-compatible IPv6
address, in the format
of ::IPv4-source-addres
s/96, where the
IPv4-source-address is
the IPv4 address of the
tunnel source.
6to4 tunneling
The source IPv4 address is
manually configured. The
destination IPv4 address is
automatically obtained.
6to4 address, in the
format of
2002:IPv4-source-addr
ess::/48, where the
IPv4-source-address is
the IPv4 address of the
tunnel source.
ISATAP tunneling
The source IPv4 address is
manually configured. The
destination IPv4 address is
automatically obtained.
ISATAP address, in the
format of
Prefix:0:5EFE:IPv4-sour
ce-address/64 where
the IPv4-source-address
is the IPv4 address of
the tunnel source.
• 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.