HP 10500 Series Configuration Manual page 165

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. It 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 11 IPv6 over IPv4 tunnel modes and key parameters
Tunnel type
Manually
configured tunnel
Automatic tunnel
IPv6 manual tunneling
1.
An IPv6 manual tunnel is a point-to-point link. Its source and destination IPv4 addresses are
manually configured. You can establish an IPv6 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
2.
A 6to4 tunnel is a point-to-multipoint automatic tunnel mainly constructed between border routers.
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 addresses 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/64, 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
border router of a 6to4 network must have the IPv4 address abcd:efgh configured on the interface
connected to the IPv4 network. The subnet number identifies a subnet in the 6to4 network. The
subnet number::interface ID uniquely identifies a host in the 6to4 network.
Tunnel mode
IPv6 manual tunneling
6to4 tunneling
Intra-site automatic tunnel
addressing protocol
(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 IP address is
automatically obtained.
156
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