6to4 tunnels at always reminds of virtual links technology in OSPF. First let’s have a quick look at what 6to4 tunnel does – Automatic 6to4 tunnel allows isolated IPv6 domains to connect over an IPv4 network Unlike the manual 6to4 the tun...
http://www.ebrahma.com/2013/12/understanding-configuring-ipv6-6to4-tunnels/Labels: 6to4-automatic-tunnel, IPv6, ipv6-6to4-tunnel