H3C Technologies H3C S12500 Series Switches - Manual (Page 215)

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Tunnel type Tunnel mode
Tunnel source/destination
address
Tunnel interface
address type
6to4 tunneling
The source IP address is a
manually configured IPv4
address. The destination IP
address need not be configured.
6to4 address, in the
format of
2002:IPv4-source-addr
ess::/48
Intra-site automatic tunnel
addressing protocol
(ISATAP) tunneling
The source IP address is a
manually configured IPv4
address. The destination IP
address need not be configured.
ISATAP address, in the
format of
Prefix:0:5EFE:IPv4-sour
ce-address/64
1. IPv6 manually configured tunnel
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.
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 more information, see "Configuring GRE."
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. 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 for the tunnel to forward IPv6
packets. A 6to4 tunnel interconnects IPv6 networks over an IPv4 network, and overcomes the
limitations of an automatic IPv4-compatible IPv6 tunnel.
{
6to4 relay