F3726, F3211, F3174, R5135, R3816-HP Firewalls and UTM Devices VPN Configuration Guide-6PW100

Hardware IPv6 over IPv6 tunnelin

com

atible

Firewall module Yes

U200-A Yes

U200-S No

IPv6 over IPv6 tunneling (RFC 2473) enables isolated IPv6 networks to communicate with each other over

another IPv6 network. For example, two isolated IPv6 networks that do not want to show their addresses

to the Internet can use an IPv6 over IPv6 tunnel to communicate with each other.

369BEncapsulation and de-encapsulation

Figure 63 Principle of IPv6 over IPv6 tunneling

702HFigure 63 shows the encapsulation and de-encapsulation processes:

• Encapsulation

a. After receiving the an IPv6 packet, Device A submits it to the IPv6 protocol stack.

b. The IPv6 protocol stack uses the destination IPv6 address of the packet to find the output

interface. If the output interface is the tunnel interface, the stack delivers it to the tunnel

interface.

c. After receiving the packet, the tunnel interface adds an IPv6 header to it and submits it to the

IPv6 protocol stack.

d. The IPv6 protocol stack forwards the packet according to its destination IPv6 address.

• De-encapsulation

e. Upon receiving the IPv6 packet, Device B delivers it to the IPv6 protocol stack.

f. The IPv6 protocol stack checks the protocol type of the data portion encapsulated in the IPv6

packet. If the encapsulation protocol is IPv6, the stack delivers the packet to the tunnel module.

g. The tunnel module de-encapsulates the packet and sends it back to the IPv6 protocol stack.

h. The IPv6 protocol stack forwards the IPv6 packet.

GRE can also realize the IPv6 over IPv6 tunneling. For related information, see "Configuring GRE."

126BProtocols and standards

• RFC 1853, IP in IP Tunneling

• RFC 2473, Generic Packet Tunneling in IPv6 Specification

• RFC 2893, Transition Mechanisms for IPv6 Hosts and Routers