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Re: Some IPv6LL operational experience




> Applications that perform referrals may fail, but I'm not aware of any 
> of these that are currently shipping and support IPv6. IPv6 is a new 
> beast, we don't have to be as concerned about applications making 
> stupid assumptions. 

you have it exactly opposite.  one of the major drivers for IPv6 will
be apps that cannot run over IPv4+NAT, and an important class of these
will be apps that do referrals.  and the stupid assumptions that are being
made is by people who think that IPv6 apps don't need to do this, and by
people who think that currently shipping IPv6 apps are representative
of future usage of IPv6.  

> If we explain that IPv6 link local addresses work 
> this way and here's a list of limitations, that's good enough. The 
> advantages of IPv6 link-local addresses far outweigh the disadvantages.

you made similar arguments for v4 link-local addresses, and you were wrong
there also.

v6 link-locals make good sense as a mechanism to provide uniform 
(independent of link technology), inherently link-local services,
like ND/RA.  they are usable by a limited class of applications, but
not applications in general. 

> IPv6LL is a major selling point. IPv6LL is a sneaky way to get everyone 
> exposed to IPv6 and to encourage developers to start supporting IPv6. 

great.  let's encourage people to use IPv6 in a dysfunctional way, one that
only works for a limited subset of apps, so that they'll never be able to
realize the real advantages of IPv6. 

I'm all for enabling ad hoc networks, and I'm all for enabling link-specific
applications.  But trying to overload IP to do these is doing real harm.  
There's nothing wrong with using the packet format on an ad hoc network, the
problem is it's the expectation that apps have that IP equates to Internet
access.  An ad hoc network is a different beast than the Internet and you
can't expect apps in general to transparently work on both kinds of network.
At the very least you need an API to allow apps to declare whether they work
on one kind or both.  And the default needs to be the Internet.

> Sure, connectivity off of the local link for those of us in the US is 
> only for a few elite,

until native v6 service is available, anybody can still run 6to4.

Keith
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