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Transition from IPv4 to IPv6
(Page 3 of 3)
IPv4-IPv6 Transition Methods
Due to the time that change takes,
IETF has been working on specific provisions to allow a smooth transition
from version 4 to version 6, and hardware and software interoperability
solutions to let newer IPv6 devices access IPv4 hosts. A technique was
included in IPv6 to allow administrators to embed
IPv4 addresses within IPv6 addresses.
Special methods are defined to handle interoperability, including:
- Dual Stack Devices: Routers
and some other devices may be programmed with both IPv4 and IPv6 implementations
to allow them to communicate with both types of hosts.
- IPv4/IPv6 Translation: Dual stack
devices may be designed to accept requests from IPv6 hosts, convert
them to IPv4 datagrams, send the datagrams to the IPv4 destination and
then process the return datagrams similarly.
- IPv4 Tunneling of IPv6: IPv6 devices that
don't have a path between them consisting entirely of IPv6-capable routers
may be able to communicate by encapsulating IPv6 datagrams within IPv4.
In essence, they would be using IPv6 on top of IPv4; two network layers.
The encapsulated IPv4 datagrams would travel across conventional IPv4
Bear in mind that these solutions
generally only address backward compatibility, to allow IPv6 devices
to talk to IPv4 hardware. Forward compatibility between IPv4 and IPv6
is not possible because IPv4 hosts cannot communicate with IPv6 hoststhey
lack the knowledge of how IPv6 works. It is possible that certain special
adaptations might be created to allow IPv4 hosts to access IPv6 hosts.
But eventually, all IPv4 devices of any importance will want to migrate
The IETF has done such a good job
in the past with introducing new technologies, and so much effort has
been put into the IPv6 transition, that I am quite confident that the
transition to IPv6 will come off with few, if any, problems. One good
thing about the transition is that IPv4 is, at the present time, still
getting the job done, so there is no big hurry to make the move to version
6. While technologies such as CIDR and NAT are band-aids
on IPv4, they have been very successful ones in extending the useful
life of the aging protocol.
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Table Of Contents - Contact Us
The TCP/IP Guide (http://www.TCPIPGuide.com)
Version 3.0 - Version Date: September 20, 2005
© Copyright 2001-2005 Charles M. Kozierok. All Rights Reserved.
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