Alcatel-Lucent OmniSwitch AOS Release 7 Manual page 293

Configuring IPv6
The following diagram illustrates the basic traffic flow between IPv6 hosts communicating over an IPv4
domain:
IPv6 6to4
Border Router
6to4 Site
6to4 Host
In the above diagram:
1
The 6to4 hosts receive 6to4 prefix from Router Advertisement.
2
The 6to4 host sends IPv6 packets to 6to4 border router.
3
The 6to4 border router encapsulates IPv6 packets with IPv4 headers and sends to the destination 6to4
border router over the IPv4 domain.
4
The destination 6to4 border router strips IPv4 header and forwards to 6to4 destination host.
6to4 Site to IPv6 Site over IPv4/IPv6 Domains
In this scenario, 6to4 sites have connectivity to native IPv6 domains through a relay router, which is
connected to both the IPv4 and IPv6 domains. The 6to4 border routers are still used by 6to4 sites for
encapsulating/decapsulating host traffic and providing connectivity across the IPv4 domain. In addition,
each border router has a default IPv6 route pointing to the relay router.
In essence, a relay router is a 6to4 border router on which a 6to4 tunnel interface is configured. However,
a native IPv6 router interface is also required on the relay router to transmit 6to4 traffic to/from IPv6 hosts
connected to an IPv6 domain. Therefore, the relay router participates in both the IPv4 and IPv6 routing
domains.
OmniSwitch AOS Release 7 Network Configuration Guide
IPv4 Domain
March 2011
IPv6 Overview
IPv6 6to4
Border Router
6to4 Site
6to4 Host
page 13-11