HPE FlexNetwork HSR6800 Configuration Manual page 288

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 10 IPv6 over IPv4 tunnel modes and key parameters
Tunnel mode
Manually configured tunnel
IPv6 over IPv4 manual
tunneling
Automatic tunnel
Automatic IPv4-compatible
IPv6 tunneling
6to4 tunneling
ISATAP tunneling
Destination IPv6 address format
Ordinary IPv6 address.
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 tunnel
destination.
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.
•
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.
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.
•
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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