>I understand, my question is strange in the IPv6 world. Here is my
>situation:
>
>I have a pure IPv6 network with a lot of computers. The subnet is
>3ffe:0:1::/48. I would like to a 6bone provider through Internet, for
>example to freenet6. I will get one /48 prefix, for example
>3ffe:b80:1234::/48. I don't want to change the IPv6 addresses and routes in
>my network and I want to reach the 6bone from all computers. And of course,
>I would like to protect my network. Hiding my network behind one IPv6
>address is not important.
>
>What is the solution?

	3ffe:0:1::/48 belongs to someone else (you picked it up at random,
	right?), so you will need to remove these address before you connect
	to the global 6bone.  so in your case, you cannot avoid renumbering.

	if you had a valid IPv6 prefix with you, and you get another
	connectivity, you can assign addresses from both prefixes to your
	machines.  so your machine will have:
		3ffe:xxxx:1:blah:blah:blah
		3ffe:b80:1234:blah:blah:blah
	unlike IPv4, you can have multiple IP addresses onto your interfaces.

itojun