Subject: RE: (ngtrans) questions about 6to4

From: Brian Zill <[email-masked]>
Date: Fri, 21 Jul 2000 16:15:36 -0700

Hi Paul,

> why not just get a native IPv6 prefix from the relay?

You're assuming you want one :-)  As Keith points out, using 6to4 results in
much more efficient use of the underlying IPv4 network when compared to the
network of configured tunnels that comprise most of 6bone today.  Until you
have native IPv6 end-to-end, you're likely to get better performance out of
6to4.

Imagine for a moment that we convince everybody (or mostly everybody) to get
6to4 addresses, regardless of whether or not they also have a native
address.  Put both addresses in the DNS and the source/destination address
selection rules will cause native connectivity to be used if it is present
at both ends, 6to4 otherwise.  Now there is no issue of finding/scaling 6to4
relays since everyone is reachable via 6to4.  We could still put up a couple
6to4 relays to handle the few folks who absolutely can't get a 6to4 prefix
for some reason, but there shouldn't be any scaling issues and finding one
is easy when we only have a small number of addresses to distribute - just
put a well-known name into the DNS that maps to them.

This is a great transition scenario.  Everyone who has at least one IPv4
address automatically has a huge amount of globally routable IPv6 address
space.  And 6to4 is trivial to set up.  No waiting on the registries.  No
worries about getting your ISP to carry IPv6 natively, you can operate just
fine while waiting for them to get with the program.  And as folks get IPv6
pipes put into place, they will get used automatically.  Bottom line: it's
more efficient than today's 6bone tunnel scheme and with almost zero
configuration hassles.

> One way is for it to know the 6to4 address of the
> relay's IPv4 interface, which amounts to a configured
> tunnel (right?).

Just a terminology nit, this isn't a configured tunnel.  It's more akin to
the automatic tunneling that is done for v4-compatible addresses.

--Brian

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From: Paul Francis <[email-masked]>
Date: Fri, 21 Jul 2000 16:32:22 -0700

> You're assuming you want one :-)  As Keith points out, using 6to4 results in

Please believe me, I was never assuming such a thing!  I had merely
observed that native IPv6 addresses is the end-goal for IPv6, and so
wondered why one wouldn't want to move towards that goal a bit quicker
given the opportunity.

> .....

So, why would anybody ever move to native IPv6 addresses once they are
happily using 6to4?  More to the point, why would an ISP ever start
offering IPv6 services if all of their customers are happily tunneling
their IPv6 over IPv4?

PF

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From: Paul Francis <[email-masked]>
Date: Fri, 21 Jul 2000 16:32:22 -0700

PF

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From: Brad Huntting <[email-masked]>
Date: Sat, 22 Jul 2000 10:48:36 -0600

> happily using 6to4? [....]

Because eventually they will want multicast.

brad