Tony Hain wrote:
>
> Brian E Carpenter wrote:
> > ...
> > > No, a link must be wholly contained within a site, and by
> > definition
> > > anything that is less than global fits wholly within global. Yes
> > > multiple local regions can overlap, but that does not
> > invalidate the
> > > overall model.
> >
> > I think it does, because it makes "less than global"
> > ambiguous. Does it mean "my intranet", "my intranet plus a
> > VPN to company X", "a VPN to company X but not my intranet",
> > "my VPNs to companies X and Y plus a secure subset of my
> > intranet", or a combinatorial number of similar choices?
>
> Why do you assume it needs a predefined meaning? I am approaching this from
> the perspective that the local network manager defines what it means in
> context. They do this all the time with routing areas, so why is a scope
> context any different?
Quite correct. What I'm pushing back on is the idea that three levels
of scope (link, local, global) capture much of anything useful. If we were
talking about scope between say 0 and 255, where 0 means link, 255 means
global, and 1..254 are user defined, we might be able to define something
of value to enterprise network operators. But that is a whole new
ball game, and not something we can tackle as part of this debate IMHO.
>
> > ...
> > > I agree with the last sentence, but not the premise about
> > defining an
> > > API. One way to describe a desired outcome would be, bind
> > to a limited
> > > range address associated with ibm.com.
> >
> > Indeed. Good example. It turns out to be a list of about 139
> > IPv4 prefixes, manually maintained. I got that from my VPN
> > setup. That's exactly the problem.
>
> So add sub-domains whenever there is a real difference in usefulness of any
> prefix in the list (fwiw: I assume that the 139 are artifacts of history,
> and there are probably less than 6 real groupings). Since these are unique,
> once the system has one it will be clear which interface or context it
> should be used with.
Certainly it's less than 139, but I suspect (without bothering to check)
more like 10 real groupings. It's significantly more than one, in any case.
> > ...
> > > > I think we'd be better off to simply forget about address scope.
> > >
> > > We could choose to ignore the most commonly deployed segment of the
> > > existing Internet, but how useful would the results be.
> >
> > That's not what I'm suggesting. I'm suggesting that trying to
> > solve it with a simple concentric-circles model of scope is
> > impossible.
>
> I doubt it is impossible. More challenging than global flat routing? Yes,
> but not impossible.
>
> In any case, I think the point you are bringing up is that truly global
> routing is a rare exception, and the vast bulk of the environment lives in
> the middle space. If so, I agree which leads to the question, why are we
> trying to optimize the address space and api's around the least likely usage
> scenario? I realize it makes app development simpler to assume the world is
> flat, but if the bulk of reality says otherwise, shouldn't we acknowledge
> that and bring app development into the 21st century?
Possibly, but it's hard, and I think we have to separate it from this debate.
Brian
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Brian E Carpenter
Distinguished Engineer, Internet Standards & Technology, IBM
NEW ADDRESS <[EMAIL PROTECTED]> PLEASE UPDATE ADDRESS BOOK
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