HP 3600 v2 Series Configuration Manual page 193

After determining from the routing table that the packet needs to be forwarded through the tunnel,
2.
Device A encapsulates the IPv6 packet with an IPv4 header and forwards it through the physical
interface of the tunnel.
Upon receiving the packet, Device B de-encapsulates the packet.
3.
Device B forwards the packet according to the destination address in the de-encapsulated IPv6
4.
packet. If the destination address is the device itself, Device B forwards the IPv6 packet to the
upper-layer protocol for processing.
Tunnel types
Depending on how the IPv4 address of the tunnel destination is acquired, IPv6 over IPv4 tunnels are
divided into the following types:
• Manually configured tunnel—The destination address of the tunnel cannot be automatically
acquired through the destination IPv6 address of an IPv6 packet at the tunnel source, and must be
manually configured.
Automatic tunnel—The destination address of the tunnel is an IPv6 address with an IPv4 address
•
embedded, and the IPv4 address can be automatically acquired through the destination IPv6
address of an IPv6 packet at the tunnel source.
Table 9 IPv6 over IPv4 tunnel modes and key parameters
Tunnel type
Manually
configured tunnel
Automatic tunnel
According to the way an IPv6 packet is encapsulated, IPv6 over IPv4 tunnels are divided into the
following modes:
IPv6 manual tunneling
•
A manually configured tunnel is a point-to-point link. Each link is a separate tunnel. IPv6 manual
tunnels are mainly used to provide stable connections for regular secure communication between
border routers or between border routers and hosts for access to remote IPv6 networks.
6to4 tunneling
•
An automatic 6to4 tunnel is a point-to-multipoint tunnel mainly constructed between edge routers,
and is used to connect multiple isolated IPv6 networks over an IPv4 network to remote IPv6
networks. The embedded IPv4 address in an IPv6 address is used to automatically acquire the
destination IPv4 address of the tunnel.
The automatic 6to4 tunnel adopts 6to4 addresses. The address format is 2002:abcd:efgh:subnet
number::interface ID/64, where 2002 represents the fixed IPv6 address prefix, and abcd:efgh
represents the 32-bit globally unique source IPv4 address of the 6to4 tunnel, in hexadecimal
Tunnel mode
IPv6 manual tunneling
6to4 tunneling
Intra-site automatic
tunnel addressing
protocol (ISATAP)
tunneling
Tunnel source/destination
address
The source/destination IP address is
a manually configured IPv4 address.
The source IP address is a manually
configured IPv4 address. The
destination IP address does not need
to be configured.
The source IP address is a manually
configured IPv4 address. The
destination IP address does not need
to be configured.
182
Tunnel interface
address type
IPv6 address
6to4 address, in the
format of
2002:IPv4-source-addr
ess::/48
ISATAP address, in the
format of
Prefix:0:5EFE:IPv4-sour
ce-address/64