Definitions

Tunneling

Tunneling provides an essential IPv6 migration mechanism. It also allows simulating VLANs.

A very likely migration scenario is that some IPv6 networks will appear at the periphery of the IPv4 Internet. Tunneling techniques make it possible to connect these IPv6 clouds without any IPv6 native connection.

The IPv6 basic specifications introduce four types of tunnels:

Configured tunnels

  • 4in4
  • 4in6
  • 6in4
  • 6in6

As detailed in the figure below, tunnels consist in encapsulating IP packets into other IP packets. These IP packets are then transmitted across the network to the tunnel end-point, where the original IP packets are extracted from the encapsulating packets

IPv4 in IPv4 configured tunnel

IPv4 in IPv4 Configured Tunnels could be useful to simulate VLANs.

An IPv4 in IPv4 configured tunnel encapsulates IPv4 traffic in an explicit IPv4 tunnel. Such a tunnel is an association of two tunnel end-points. For each end-point, an encapsulated IPv4 and an encapsulating IPv4 addresses have to be configured.

IPv4 in IPv6 configured tunnel

IPv4 in IPv6 Configured Tunnels could be useful for the interconnection of IPv4 clouds on an IPv6 native service.

An IPv4 in IPv6 configured tunnel encapsulates IPv4 traffic in an explicit IPv6 tunnel. Such a tunnel is an association of two tunnel end-points. For each end-point, an IPv4 and an IPv6 addresses have to be configured.

IPv6 in IPv4 configured tunnel

An IPv6 in IPv4 configured tunnel encapsulates IPv6 traffic in an explicit IPv4 tunnel. Such a tunnel is an association of two tunnel end-points. For each end-point, an IPv4 and an IPv6 addresses have to be configured.

IPv6 in IPv6 configured tunnel

IPv6 in IPv6 configured tunnels could be useful to simulate VLANs.

An IPv6 in IPv6 configured tunnel encapsulates IPv6 traffic in an explicit IPv6 tunnel. Such a tunnel is an association of two tunnel end-points. For each end-point, an encapsulated IPv6 and an encapsulating IPv6 addresses have to be configured.