Ipv4 Over Ipv6 Tunneling - HP 3600 v2 Series Configuration Manual

Figure 84 Principle of IPv4 over IPv4 tunneling
Packets traveling through a tunnel undergo encapsulation and de-encapsulation processes, as shown
in Figure 84.
Encapsulation
•
The encapsulation follows these steps.
Device A receives an IP packet from an IPv4 host and submits it to the IP protocol stack.
a.
The IP protocol stack determines how to forward the packet according to the destination
b.
address in the IP header. If the packet is destined for the IPv4 host connected to Device B,
Device A delivers the packet to the tunnel interface.
The tunnel interface encapsulates the packet into an IPv4 packet and submitted to the IP
c.
protocol stack for processing. The IP protocol stack determines the outgoing interface of the
tunnel according to the IP header, and sends the packet out.
De-encapsulation
•
The de-encapsulation follows these steps.
After receiving the packet, Device A delivers it to the IP protocol stack, which then checks the
a.
protocol number in the IP header.
If the protocol number is IPv4 (indicating an IPv4 packet is encapsulated within the packet), the
b.
IP packet is sent to the tunnel module for de-encapsulation.
The de-encapsulated IP packet is sent back to the IP protocol stack for processing.
c.

IPv4 over IPv6 tunneling

IPv4 over IPv6 tunneling adds an IPv6 header to IPv4 packets so that the IPv4 packets can traverse an
IPv6 network and reach another IPv4 network.
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