HPE 3100 Configuration Manual page 187

4. Device B forwards the packet according to the destination address in the de-encapsulated IPv6
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 notation. For example, 1.1.1.1 can be represented by 0101:0101. The
part that follows 2002:abcd:efgh uniquely identifies a host in a 6to4 network. The tunnel
destination is automatically determined by the embedded IPv4 address, which makes it easy to
create a 6to4 tunnel.
The tunnel can forward IPv6 packets because the 16-bit subnet number of the 64-bit address
prefix in 6to4 addresses can be customized and the first 48 bits in the address prefix are fixed to
a permanent value and the IPv4 address of the tunnel source or destination.
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.
177
Tunnel interface
address type
IPv6 address
6to4 address, in the
format of
2002:IPv4-source-add
ress::/48
ISATAP address, in
the format of
Prefix:0:5EFE:IPv4-so
urce-address/64