IPv6 cloud and IPv4 ocean

At this moment, internet infrastructure uses IPv4
How IPv6 sites communicate?
-> tunnelling

RFC2893 defines IPv6-over-IPv4 tunnelling
Can be used just like IPv6 p2p link
We run IPv6 routing protocol on top of it


  += IPv6-over-IPv4 tunnel =+
  |                         |
((IPv6 network))      ((IPv6 network))