Ipv4 Over Ipv6 Tunneling - H3C MSR 2600 Configuration Manual

IPv4 over IPv6 tunneling

Implementation
IPv4 over IPv6 tunneling adds an IPv6 header to IPv4 packets so that IPv4 packets can pass an IPv6
network through a tunnel to realize interworking between isolated IPv4 networks.
Figure 98 IPv4 over IPv6 tunnel
Packets traveling through a tunnel undergo encapsulation and de-encapsulation, as shown in
Encapsulation:
•
Upon receiving an IPv4 packet, Device A delivers it to the IPv4 protocol stack.
a.
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 tunnels include the following modes:
IPv4 over IPv6 manual tunnel
•
A point-to-point 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
240
Figure 98.