HP FlexNetwork MSR2003 Configuration Manual page 299

In the IPv4 header, the source IPv4 address is the IPv4 address of the tunnel source, and
the destination IPv4 address is the IPv4 address of the tunnel destination.
3. Upon receiving the packet, Device B de-encapsulates the packet.
4. If the destination address of the IPv6 packet is itself, Device B forwards it to the upper-layer
protocol. If it is not, Device B forwards it according to the routing table.
Tunnel modes
IPv6 over IPv4 tunnels include manually configured tunnels and automatic tunnels, depending on
how the IPv4 address of the tunnel destination is obtained.
•
Manually configured tunnel—The destination IPv4 address of the tunnel cannot be
automatically obtained 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 obtained
from the destination IPv6 address (with an IPv4 address embedded) of an IPv6 packet at the
tunnel source.
The source IPv4 addresses for all IPv6 over IPv4 tunnels are manually configured.
According to the way an IPv6 packet is encapsulated, IPv6 over IPv4 tunnels are divided into the
modes shown in the following table:
Table 11 IPv6 over IPv4 tunnel modes and key parameters
Tunnel type
Manually
configured
tunnel
Automatic
tunnel
Tunnel mode Destination IPv6 address format
IPv6 over IPv4
Ordinary IPv6 address.
manual tunneling
IPv4-compatible IPv6 address. The address format is
0:0:0:0:0:0:a.b.c.d/96, where a.b.c.d is the IPv4 address of the
Automatic
tunnel destination.
IPv4-compatible
IPv6 tunneling
NOTE:
The tunnel source also uses an IPv4-compatible IPv6 address.
6to4 address. The address format is 2002:abcd:efgh:subnet
number::interface ID/48.
•
•
6to4 tunneling
•
•
NOTE:
The destination IPv4 address of a 6to4 tunnel is embedded in the
destination 6to4 address. This mechanism enables the device to
automatically obtain the tunnel destination address.
ISATAP address. The address format is
prefix:0:5EFE:abcd:efgh/64.
•
ISATAP tunneling
•
2002 is the fixed IPv6 address prefix.
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.
The 64-bit prefix is a valid IPv6 unicast address prefix.
The abcd:efgh/64 segments represent a 32-bit IPv4 address,
which identifies the tunnel destination but does not require
global uniqueness.
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