Configuring Tunneling; Overview; Ipv6 Over Ipv4 Tunneling - HP 6125G Configuration Manual

Configuring tunneling

Overview

Tunneling is an encapsulation technology: one network protocol encapsulates packets of another
network protocol and transfers them over a virtual point-to-point connection. The virtual connection is
called a tunnel. Packets are encapsulated and de-encapsulated at both ends of a tunnel. Tunneling refers
to the whole process from data encapsulation to data transfer to data de-encapsulation.
Tunneling provides the following features:
• Transition techniques, such as IPv6 over IPv4 tunneling, to interconnect IPv4 and IPv6 networks.
Virtual Private Networks (VPNs) for guaranteeing communication security, such as IPv4 over IPv4
•
tunneling, IPv4/IPv6 over IPv6 tunneling, Generic Routing Encapsulation (GRE), Dynamic Virtual
Private Network (DVPN), and IPsec tunneling.
Traffic engineering, such as Multiprotocol Label Switching traffic engineering (MPLS TE) to prevent
•
network congestion.
Unless otherwise specified, the term "tunnel" used throughout this chapter refers to an IPv6 over IPv4,
IPv4 over IPv4, IPv4 over IPv6, or IPv6 over IPv6 tunnel.

IPv6 over IPv4 tunneling

Implementation
IPv6 over IPv4 tunneling adds an IPv4 header to IPv6 data packets so that IPv6 packets can pass an IPv4
network through a tunnel to realize internetworking between isolated IPv6 networks, as shown in
58. The IPv6 over IPv4 tunnel can be established between two hosts, a host and a device, or two devices.
The tunnel destination node can forward IPv6 packets if it is not the destination of the IPv6 packets.
The devices at both ends of an IPv6 over IPv4 tunnel must support the IPv4/IPv6 dual stack.
Figure 58 IPv6 over IPv4 tunnel
The IPv6 over IPv4 tunnel processes packets in the following ways.
A host in the IPv6 network sends an IPv6 packet to Device A at the tunnel source.
1.
119
Figure