H3C S7500E Series Ethernet Switches Operation Manual

Operation Manual – IPv6 Configuration
H3C S7500E Series Ethernet Switches Chapter 3 Tunneling Configuration
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z If the IPv4 address of the tunnel destination cannot be acquired from the
destination address of the IPv6 packet, it needs to be configured manually. Such a
tunnel is called a configured tunnel.
z If the IPv4 address is embedded into the IPv6 address, the IPv4 address of the
tunnel destination can automatically be acquired from the destination address of
the IPv6 packet. Such a tunnel is called an automatic tunnel.
III. Type
According to the way an IPv6 packet is encapsulated, IPv6 over IPv4 tunnels are
divided into the following types:
z IPv6 manual tunnel
z 6to4 tunnel
z ISATAP tunnel
Among the above tunnels, the IPv6 manual tunnel is a configured tunnel, while the 6to4
tunnel, and intra-site automatic tunnel address protocol (ISATAP) tunnel are automatic
tunnels.
1) IPv6 manually configured tunnel
A manually configured tunnel is a point-to-point link. One link is a separate tunnel. The
IPv6 manually configured tunnels provide stable connections requiring regular secure
communication between two border routers or between a border router and a host for
access to remote IPv6 networks.
2) 6to4 tunnel
An automatic 6to4 tunnel is a point-to-multipoint tunnel 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 of the
tunnel. The automatic 6to4 tunnel adopts 6to4 addresses. The address format is
2002:abcd:efgh:subnet number::interface ID/64, where abcd:efgh represents the 32-bit
source IPv4 address of the 6to4 tunnel, in hexadecimal notation. For example, 1.1.1.1
can be represented by 0101:0101. The tunnel destination is automatically determined
by the embedded IPv4 address, which makes it easy to create a 6to4 tunnel.
Since 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 by a permanent value
and the IPv4 address of the tunnel source or destination, it is possible that IPv6 packets
can be forwarded by the tunnel.
3) ISATAP tunnel
With the application of the IPv6 technology, there will be more and more IPv6 hosts in
the existing IPv4 network. The ISATAP tunneling technology provides a satisfactory
solution for IPv6 application. An ISATAP tunnel is a point-to-point automatic tunnel. The
destination of a tunnel can automatically be acquired from the embedded IPv4 address
in the destination address of an IPv6 packet. When an ISATAP tunnel is used, the