Alcatel-Lucent 6850-48 Network Guide

IPv6 Overview

Configuring IPv6

page 26-10

OmniSwitch AOS Release 6 Network Configuration Guide

It is likely that IPv6 and IPv4 network infrastructures will coexist for some time, if not indefinitely. 
Tunneling provides a mechanism for transitioning an IPv4 network to IPv6 and/or maintaining interopera-
bility between IPv4 and IPv6 networks. This implementation of IPv6 supports tunneling of IPv6 traffic 
over IPv4. There are two types of tunnels supported, 6to4 and configured.

Note. RIPng is not supported over 6to4 tunnels. However, it is possible to create a RIPng interface for a 
configured tunnel. See 

 for more information.

6to4 tunneling provides a mechanism for transporting IPv6 host traffic over an IPv4 network infrastruc-
ture to other IPv6 hosts and/or domains without having to configure explicit tunnel endpoints. Instead, an 
IPv6 6to4 tunnel interface is created at points in the network where IPv6 packets are encapsulated (IPv4 
header added) prior to transmission over the IPv4 network or decapsulated (IPv4 header stripped) for 
transmission to an IPv6 destination.

An IPv6 6to4 tunnel interface is identified by its assigned address, which is derived by combining a 6to4 
well-known prefix (2002) with a globally unique IPv4 address and embedded as the first 48 bits of an IPv6 
address. For example, 2002:d467:8a89::137/64, where D467:8A89 is the hex equivalent of the IPv4 
address 212.103.138.137.

6to4 tunnel interfaces are configured on routers and identify a 6to4 site. Because 6to4 tunnels are point-to-
multi-point in nature, any one 6to4 router can communicate with one or more other 6to4 routers across the 
IPv4 cloud. Two common scenarios for using 6to4 tunnels are described below.

In this scenario, isolated IPv6 sites have connectivity over an IPv4 network through 6to4 border routers. 
An IPv6 6to4 tunnel interface is configured on each border router and assigned an IPv6 address with the 
6to4 well-known prefix, as described above. IPv6 hosts serviced by the 6to4 border router have at least 
one IPv6 router interface configured with a 6to4 address. Note that additional IPv6 interfaces or external 
IPv6 routing protocols are not required on the 6to4 border router.

The following diagram illustrates the basic traffic flow between IPv6 hosts communicating over an IPv4 
domain: