Integrating IPv4 and IPv6
There are several strategies for migrating from IPv4 to IPv6. Each of these
strategies should be considered when organizations decide to make the move
to IPv6 because each has positive points to aiding a smooth migration. It
should also be said that there does not have to be a global decision on strategy—
your organization may choose to run dual-stack in the U.S., go
completely to IPv6 in Japan, and use tunneling in Europe. The transition
mechanisms include:
■ Dual stack—Running IPv6 and IPv4 concurrently.
■ IPv6 to IPv4 tunneling (6-to-4)—Routers that straddle the IPv4 and
IPv6 worlds to encapsulate the IPv6 traffic inside IPv4 packets.
■ Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)—This
protocol is similar to 6-to-4, but it treats the IPv4 network as an
NBMA network.
■ Teredo/Shipworm—Encapsulates IPv6 packets in IPv4/UDP segments.