H3C Technologies H3C SecPath F1000-E - Manual (Page 150)

4
Tunnel mode Source/destination IP address of the tunnel
IP address of the tunnel
interface
6to4 tunnel
The source IP address is a manually configured IPv4
address, while the destination IP address does not
need to be configured.
6to4 address, in the format of
2002:IPv4-source-address::/48
ISATAP tunnel
The source IP address is a manually configured IPv4
address, while the destination IP address does not
need to be configured.
ISATAP address, in the format of
Prefix:0:5EFE:IPv4-source-addre
ss/64
1. IPv6 manually configured tunnel
A manually configured tunnel is a point-to-point link. Each link is a separate tunnel. IPv6 manually
configured 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.
2. GRE tunnel
IPv6 packets can be carried over GRE tunnels to pass through an IPv4 network. Like the IPv6 manually
configured tunnel, a GRE tunnel is a point-to-point link. Each link is a separate tunnel. GRE tunnels are
mainly used to provide stable connections for secure communication between border routers or between
host and border router. For related configurations, see GRE Configuration in the VPN Volume.
3. Automatic IPv4-compatible IPv6 tunnel
An automatic IPv4-compatible IPv6 tunnel is a point-to-multipoint link. IPv4-compatible IPv6 addresses
are adopted at both ends of such a tunnel. The address format is 0:0:0:0:0:0:a.b.c.d/96, where a.b.c.d
represents an embedded IPv4 address. The tunnel destination is automatically determined by the
embedded IPv4 address, which makes it easy to create a tunnel for IPv6 over IPv4. However, an
automatic IPv4-compatible IPv6 tunnel must use IPv4-compatible IPv6 addresses and it is still dependent
on IPv4 addresses. Therefore, automatic IPv4-compatible IPv6 tunnels have limitations.
4. 6to4 tunnel
• Ordinary 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 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.
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, it is possible that IPv6 packets can be forwarded by the tunnel. A 6to4 tunnel
interconnects IPv6 networks over an IPv4 network, and overcomes the limitations of an automatic
IPv4-compatible IPv6 tunnel.
• 6to4 relay
A 6to4 tunnel is only used to connect 6to4 networks, whose IP prefix must be 2002::/16. However, IPv6
network addresses with the prefix such as 2001::/16 may also be used in IPv6 networks. To connect a