Keith Moore wrote:
> for LL as currently defined, ambiguity is part of the 
> equation. another kind of address might provide a way to 
> resolve that ambiguity.

There is nothing about the address type the creates ambiguity. These
addresses are not meant to be used off of the current link. That means not
forwarding packets containing them to other links (including in the content
part). Since the routers will only see the headers, it becomes the
application's responsibility to keep them on-link. If the application can't
do that it simply can't put them in packets.

> networks are designed to support apps.  it's not as if apps 
> can tolerate arbitrary amounts of delay, loss, jitter, etc.  
> providing sane addressing is just another aspect of good 
> network design.

Networks and applications are designed to allow people to accomplish tasks.
Sometimes the network designs are focused on very specific tasks and the
applications needed to accomplish them. The fact that other apps are run on
that same network is an artifact of the flexibility of IP. Trying to require
the network to be designed to optimally support the other apps is not
realistic.

> 
> > Expecting the network to be globally
> > accessable and flat is not reality.
> 
> the network has never been flat in reality, but part of the 
> purpose of IP has always been to provide the illusion of a 
> flat network.

That would be the purpose of the illusionary session layer ...

>  we're also a long way from any time when it 
> could be expected that every host in the network could access 
> any other host in the network, but nobody's asking for that 
> now (and I wish you'd stop claiming that people were).

'networks are designed to support apps. ' appears to be demanding that the
network provide global accessibility.

> ...
> yes, it can - because it's a slippery slope from saying 
> "here's a hint" to "it's okay to do this".  and the hints 
> aren't of much use to the apps 

For the apps you care about, maybe, but that does not represent all apps. 

> unless it's to say "it's okay to ignore these addresses". 
>  what you're arguing is that it's 
> not okay for apps to ignore these addresses - and that makes 
> the hints irrelevant.

It is not ok to ignore them, but it is ok to use the hint in prioritizing.
Some apps will want to prioritize them high while others like your favorites
will want to prioritize them low. Refusing to allow them to be used only
ensures that app doesn't work without explicit manual intervention. Since
many of the target environments are trying to avoid explicit manual
intervention, they need to be used.

Tony


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