On day IP version 6 will become the default protocol used on the internet, but until that
happens you are going to have networks that need to run IP version 4, IP version 6 or
both. There are a number of technologies to help you make the transition from IP version
4 to Ip Version 6. In this section I will look at the transition
technologies that are available to make the change from IP version 4 to IP version 6.
The first of these is ISATAP.Isatap is used inside a private network. If you are planning
to access the internet you can used a system like 6 to 4. 6 to 4 is a transition protocol
designed to help people migrate to IP version 6.
The last transition protocol I will look at is Teredo. Teredo is used when your company
is using a NAT device. The protocol relies on external servers which many ISP’s and
even Microsoft have placed on the internet to help with the transition.
There is still a lot of work that needs to be done before everyone is switched over to
IP version 6. To try and assist the migration to IP version 6 there are some transition
technologies that have been developed. These are needed because IP version 6 has a different
header to IP version 4. This does not effect layer 2 of the OSI model as layer 2 devices
will work with the new header. This means you can deploy your IP version 6 network with
out having to upgrade your hubs and switches. However, because the IP header has been changed,
layer 3 devices need to be upgraded to IP version 6 before they will work on a IP version
6 network. You can image that many company won’t want to upgrade all there routers
to IP version 6 any time soon so the need for transition technologies are needed.
The first is what Microsoft call next generation TCP IP. Simply put this means Windows Server
2008 allows both the IP version 4 stack and IP version 6 stack to be used on the same
computer. Windows will attempt to automatically decide which to use. A lot of commands support
the dash 4 and dash 6 switches. These switches force windows to use either the IP version
4 protocol or the IP version 6 protocol. Even with next generation TCP IP, since the
whole internet is not yet IP version 6 ready, you may have a situation in which you need
to go over the IP version 4 network to reach a IP version 6 client and this is where transition
technologies come into play. ISATAP or Intra site automatic tunnel addressing
protocol is enabled by default in windows server 2008. ISATAP is intended to be used
in a private networks only. In can’t be used on the internet. In your organisation,
if you have a IP version 4 network and a IP version 6 network and you want to communicate
between the networks, notice there is no common protocol between the two networks. What you
can do is install an ISATAP router between the networks.
If a computer on the IP version 4 network wants to communicate with a computer on the
IP version 6 network, the computer first communicates to the ISATAP router using IP version 4. In
order for the a host on the IP version 6 network to receive the communication, the router must
communicate to the IP version 6 host in IP 6. To do this, the router uses a link local
address. Remember link local addresses always start with FE80 and are used for local traffic
only. In the host part of the address you have 5EFE followed by the IP version 4 address.
Consider the follow example. To communicate with 10 dot 0 dot 30 dot 120, the router would
used the link local address host network ID fe80 followed by the host ID of 5EFE colon
10 dot 0 dot 30 dot 120. If a client on the IP version 6 network wants
to communicate with the IP version 4 network, the process is simply reversed. With Windows
Server 2008 and Windows Vista ISATAP is enabled by default. To get it to work you will need
to configure your ISATAP router. Also your hosts will need to be able to locate the ISATAP
router so you will need to add it to DNS. The good thing with ISATAP is that you do
not need to perform any configuration on Windows Vista or Windows 7. These clients will detect
and use ISATAP automatically. ISATAP does not support any routing so the network you
want to connect to must be connected to the ISTAP router and thus ISTAP can only be used
inside a companies network and not on the internet.
6 to 4 is designed as a transition protocol to help the adopting of IP version 6. It is
not developed to be a long term solution. 6 to 4 allows existing IP version 4 networks
to be used to tunnel IP version 6 traffic. Consider this example. There are two IP version
6 networks and you want to communicate between them. Between them you have the internet which
at this time is mostly IP version 4 with very little IP version 6 routing. To communicate
between the two networks a 6 to 4 router is used to tunnel the IP version 6 protocol over
the internet. To do this, a public IP version 6 ip address is used.
These addresses all start with 2002 followed by the IP version 4 address shown here as
w, x y and z, followed by the subnet ID and interface ID. You may be thinking while would
you not establish a tunnel between the two sites. Consider this more complex example.
The communication leaves the IP version 6 network and enters an IP version 4 network.
The communication then travels to a 6 to 4 router and enters an IP version 6 network.
From here it gets routed through a IP version 6 network but unfortunately there is no IP
version 6 network to the destination network. The communication again gets tunnel through
a IP version 4 network to anther 6 to 4 router which has a connection to the destination
network. As the internet becomes more and more IP version 6 ready, your data will be
routed through this network and less of the IP version 4 network.
Using 6 to 4 also allows your clients to connect to IP version 4 hosts, however IP version
4 hosts will not be able to connect to IP version 6 hosts. Using 6 to 4 you could do
the following. The computers in the IP version 6 network
can have any valid IPv6 address. The 6 to 4 router has one valid 6to4 IP address. Using
this IP address your network can communicate with any IP version 4 computer on the internet,
however they can not connect to you. Using the 6 to 4 protocol, you can start deploying
your IP version 6 network and still keep accessing the IP version 4 network.
Slide 8 The next transition technology is Teredo.
This is available in Windows Server 2008,Windows Vista, windows 7 and windows xp. You would
use Teredo when you have a IP version 4 NAT device that your clients connect to. If you
have a situation in which your company wants to start using IP version 6 but does not want
to upgrade the IP version 4 NAT device, you may need to use Teredo. Consider this network.
The clients on the network connect to the IP version 4 device to access the internet.
The NAT device has one public IP version 4 address.
In order to connect to a IP version 6 host, the clients contact a terdeo server. The teredo
server gives the client an IP address to a Teredo relay. The client create a tunnel to
the teredo relay. All the communication between the client and the Teredo relay is in IP version
4 which makes the communication compatible with the NAT device. The client can than use
the tunnel to sent it’s IP version 6 traffic to it’s destination.
In the real world IP version 4 will be around for a long time yet. Believe it or not IP
version 6 has been around since 1996, however development and support has been slow. Today
only a small part of the internet is IP version 6. Adoption has been slow, however some countries
like China have deployed a lot of IP version 6 networks, most notable was the Olympic games
in 2008 which were completely IP version 6. All network operations were conducted in IP
version 6 and even the web page was available in IP version 6. The china Olympics provided
the largest showcase to date of IP version 6.
Back in the real world, the reality is there is also a lack of IP version 6 devices. If
you attempt to buy a dsl modem for home that’s use IP version 6 you may have trouble finding
one and it probably will not be cheap. Companies won’t want to foot the build to upgrade
their networks to IP version 6 until the prices come or until there is a real business need.
IP version 4 still meets most companies business needs and this is unlikely to change any time
soon. If you want to learn more about IP version
6 and want to give it a try, I would recommend visiting http://gogonet.gogo6.com. Go go 6
supplies access to the IP version 6 network and even provides a free client you can install
on your computer. Once you install the client you can access the Ip version 6 network with
your own valid IP version 6 address. If you want to experiment and learn about
IP version 6 this is a great way to do it with out having to upgrade any devices on
your existing network. A lot of demonstrations performed in this course using IP version
6 are done with the go6.net client. Good luck with IP version 6.