IPv6

IPv4 World ↔ 192.88.99.16to4 relay2002:x.x.x.x::/48 ↔ IPv6 World

192.88.99.1 is an anycast address of the nearest 6to4 relay

2002:x.x.x.x::/48 is an anycast route of the nearest 6to4 relay

On one side of the IPv4 net is an 6to4 relay, on the other an 6to4 router or host

IPv4 Hosts get an IPv6 Net

IPv6 Hosts get nothing (they know “I'm talking to an 'IPv4 host'” but they don't get an IPv4 IP/Net)

IPv6 encapsulated in IPv4
IPv4(Type=41, Src=x.x.x.x, Dst=192.88.99.1, Payload=IPv6(Src=2002:x.x.x.x, Dst=Dst))

2002::/16 gets an public IPv4 Address appended ⇒ 2002:x.x.x.x::/48 ⇒ 16 Bit remaining for subnets.

Unmanaged: Automatically finds nearest Router per anycast

As an public IPv4 is required, it's hard to NAT

Like 6to4, but with explicitly configured relays (managed)

On both sides of the IPv4 only net are relays or hosts

Both have to configure the IPv4 IP of the other endpoint ⇒ Only usable for static IPv4 addresses.

Not dependent on an 2002::/16 net

Solves the NATing problems of 6in4 and 6to4 by using NATable transport protocols (UDP, TCP, SCTP)

Prevents spoofing by signing packages

Prevents replaying

Does not encrypt packages

Still has problems with dynamic IPv4 addresses (those transport protocols does not support roaming)

Software/Protocol developed by SixXS to make 6in4 and AYIYA usable for dynamic IPv4 addresses (informs the other endpoint about new IPv4 address)

Also used by HE

IPv6 representations of IPv4 addresses

IPv4-Mapped IPv6 Address: ::FFFF:x.x.x.x

IPv4-Compatible IPv6 Address: ::x.x.x.x(deprecated)