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Re: 6to4 considered a bad thing



On Feb 1, 2008, at 15:23, Alain Durand wrote:
On 2/1/08 4:56 PM, "Gert Doering" <gert@space.net> wrote:
On Fri, Feb 01, 2008 at 03:46:22PM -0500, Alain Durand wrote:
Essentially, expecting to get a functioning 6to4 relay is expecting a free
lunch. Who is going to pay for it?

If enough ISPs provide working 6to4 relays, serving their own customers (that pay for the bandwidth, be it IPv4 or IPv4-encapsulated IPv6), the
model would work just fine.

Why should ISP X pay to run a 6to4 relay that would in essence offer transit
for customers of other ISPs?

No one here is asking for ISP X to advertise its 6to4 relays at public anycast addresses (either IPv4 or IPv6) into the default free zone.

I think the question you want to ask is this one: why should ISP X offer 6to4 relay service to its IPv4 customers when it can force them to pay extra for the additional utility of native IPv6 service? Admittedly, I don't have an answer to that question, except to say that the "additional utility" of IPv6 is limited by the fact that 2002::/16 effectively divorced from the IPv6 default free zone by those same network operators insisting that interior 6to4 relays are harmful to their insert-noun-phrase-here.

And let's say that ISP X offer the outband
relay for its customers only, how would the packets come back from the real
IPv6 Internet to ISP X IPv4 network?

By an asymmetric IPv4 path, of course. The 6to4 relay is only a transition mechanism. It doesn't have to work as well as native IPv6. It just has to work. If it doesn't work *at all*, then we should deprecate it.

Is ISP X suppose to announce a
de-aggregate of 2002://16? That would create a huge increase in the routing
table size...

That's clearly not a good idea.


--
james woodyatt <jhw@apple.com>
member of technical staff, communications engineering