HPE FlexNetwork HSR6800 Configuration Manual page 291

Figure 111 IPv4 over IPv6 tunnel
Figure 111 shows the encapsulation and de-encapsulation processes.
•
Encapsulation:
a. Upon receiving an IPv4 packet, Device A delivers it to the IPv4 protocol stack.
b. The IPv4 protocol stack uses the destination address of the packet to determine the egress
interface. If the egress interface is the tunnel interface, the IPv4 protocol stack delivers the
packet to the tunnel interface.
c. The tunnel interface adds an IPv6 header to the original IPv4 packet and delivers the packet
to the IPv6 protocol stack.
d. The IPv6 protocol stack uses the destination IPv6 address of the packet to look up the
routing table, and then sends it out.
•
De-encapsulation:
e. Upon receiving the IPv6 packet from the attached IPv6 network, Device B delivers the
packet to the IPv6 protocol stack to examine the protocol type encapsulated in the data
portion of the packet.
f. If the protocol type is IPv4, the IPv6 protocol stack delivers the packet to the tunneling
module.
g. The tunneling module removes the IPv6 header and delivers the remaining IPv4 packet to
the IPv4 protocol stack.
h. The IPv4 protocol stack forwards the IPv4 packet.
Tunnel modes
•
IPv4 over IPv6 manual tunnel
A point-to-point virtual link and its source and destination IPv6 addresses are manually
configured. You can establish an IPv4 over IPv6 manual tunnel to connect isolated IPv4
networks over an IPv6 network.
•
DS-Lite tunnel
Dual Stack Lite (DS-Lite) is a combination of the tunneling and NAT technologies. NAT
translates the private IPv4 addresses of the IPv4 hosts before the hosts reach the IPv4 public
network.
DS-Lite tunnel supports only an IPv4 host in a private network initiating communication with an
IPv4 host on the Internet. It does not support an IPv4 host on the Internet initiating
communication with an IPv4 host in a private network.
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