IPv6 tunneling

1) Manual
2) 6to4
3) Teredo
4) ISATAP

Manual

Example configuration:

Router(config)# interface tunnel0
Router(config-if)# ipv6 address 2001:0:1:5::1/64
Router(config-if)# tunnel source 192.168.1.1
Router(config-if)# tunnel destination 192.168.2.1
Router(config-if)# tunnel mode ipv6ip

6-to-4 Tunnels

6-to-4 tunnels work similar to manual tunnels but are set up automatically.6-to-4 tunnels concatenate 2002::/16 with the 32-bit IPv4 address of the edge router, creating a 48-bit prefix.

Ex: The tunnel interface on Router A has
an IPv6 prefix of 2002:C0A8:501::/48, where C0A8:501 is the hexadecimal equivalent of
192.168.5.1, the IPv4 address of its interface in the IPv4 network.

Teredo
Another type of tunnel is called Teredo (also known as shipworm). Teredo encapsulates IPv6
packets in IPv4/UDP segments and works similarly to other tunnels but with the added benefit of
being able to traverse network address translation (NAT) devices and firewalls. Teredo is described
in RFC 4380, Teredo: Tunneling IPv6 over UDP through Network Address Translations (NAT).

ISATAP
ISATAP treats the IPv4 network as an NBMA network and allows an IPv4 private network to
incrementally implement IPv6 without upgrading the network. ISATAP is documented in RFC
4214, Intra-Site Automatic Tunnel Addressing Protocol (ISATAP).