Datasheet

“main” (Installation and Administration) — 2004/6/25 — 13:29 — page 430 — #456

However, the conﬁguration and maintenance of static tunnels is often too

labor-intensive to use them for daily communication needs. Therefore, IPv6

provides for three different methods of dynamic tunneling:

6over4 IPv6 packets are automatically encapsulated as IPv4 packets and

sent over an IPv4 network capable of multicasting. IPv6 is tricked

into seeing the whole network (Internet) as a huge local area net-

work (LAN). This makes it possible to determine the receiving end

of the IPv4 tunnel automatically. However, this method does not scale

very well and it is also hampered by the fact that IP multicasting is far

from widespread on the Internet. Therefore, it only provides a solu-

tion for smaller corporate or institutional networks where multicast-

ing can be enabled. The speciﬁcations for this method are laid down

in RFC 2529.

6to4 With this method, IPv4 addresses are automatically generated from

IPv6 addresses, enabling isolated IPv6 hosts to communicate over an

IPv4 network. However, a number of problems have been reported

regarding the communication between those isolated IPv6 hosts and

the Internet. The method is described in RFC 3056.

IPv6 Tunnel Broker This method relies on special servers that provide

dedicated tunnels for IPv6 hosts. It is described in RFC 3053.

Note

The 6bone Initiative

In the heart of the “old-time” Internet, there is already a globally

distributed network of IPv6 subnets that are connected through

tunnels. This is the 6bone network (www.6bone.net), an IPv6

test environment that may be used by programmers and Internet

providers who want to develop and offer IPv6-based services to

gain the experience necessary to implement the new protocol.

More information can be found on the project’s Internet site.

Note

21.2.4 For More Information

The above overview does not cover the topic of IPv6 comprehensively. For

a more in-depth look at the new protocol, refer to the following online doc-

umentation and books:

430 21.2. IPv6 — The Next Generation Internet