HP 4800G Series Configuration Manual page 368

3) The encapsulated packet goes through the tunnel to reach the device at the destination end of the
tunnel. The device at the destination end decapsulates the packet if the destination address of the
encapsulated packet is the device itself.
4) The destination device forwards the packet according to the destination address in the
decapsulated IPv6 packet. If the destination address is the device itself, the device forwards the
IPv6 packet to the upper-layer protocol for processing.
Configured tunnel and automatic tunnel
An IPv6 over IPv4 tunnel can be established between hosts, between hosts and devices, and between
devices. The tunnel destination needs to forward packets if the tunnel destination is not the final
destination of the IPv6 packet.
Tunnels are divided into configured tunnels and automatic tunnels depending on how the IPv4 address
of the tunnel destination is acquired.
If the destination address of an IPv6 over IPv4 tunnel cannot be acquired from the destination
address of IPv6 packets, it needs to be configured manually. Such a tunnel is called a configured
tunnel.
If the interface address of an IPv6 over IPv4 tunnel has an IPv4 address embedded into an IPv6
address, the IPv4 address of the tunnel destination can be acquired automatically. Such a tunnel is
called an automatic tunnel.
Type
According to the way an IPv6 packet is encapsulated, IPv6 over IPv4 tunnels are divided into the
following types:
Tunnel type
Manually configured tunnel
Automatic tunnel
The configuration parameters for each tunnel mode are listed in the following table:
Tunnel mode
IPv6 manual tunnel
6to4 tunnel
ISATAP tunnel
1) IPv6 manually configured tunnel
IPv6 manual tunnel
6to4 tunnel
Intra-site automatic tunnel addressing protocol (ISATAP) tunnel
Source/destination IP address of the
tunnel
The source/destination IP address is a
manually configured IPv4 address.
The source IP address is a manually
configured IPv4 address, while the
destination IP address does not need to
be configured.
The source IP address is a manually
configured IPv4 address, while the
destination IP address does not need to
be configured.
1-3
Tunnel mode
IP address of the tunnel
interface
IPv6 address
6to4 address, in the format of
2002:IPv4-source-address::/48
ISATAP address, in the format
of
Prefix:0:5EFE:IPv4-source-add
ress/64