Date: Sat, 19 Apr 2003 17:27:13 -0400
From: Keith Moore <moore@cs.utk.edu>
Message-ID: <20030419172713.4c34e197.moore@cs.utk.edu>
| not to encourage that error to the point that it became common
| practice (as has happened).
Usage alters to meet the demands of the users. That's nothing new.
| on the contrary, having an enterprise use both SLs and globals creates
| significant new problems of its own, and results in even less flexibility
| than if SLs were used only by isolated networks.
Nothing that IPv4 doesn't have as well (if perhaps less commonly).
| multiple addresses at a node were available in IPv4, but the problems
| associated with doing this have never been solved, not even in IPv6.
True. But it is still used regardless. There are unsolved problems
should be a challenge, not something to fear.
| so while having multiple prefixes per node is clearly useful for
| renumbering,
Yes - but more than that - as long as addresses reflect topology, multiple
addresses are the only way to have multiple topological attachments,
aren't they?
This is seen both in a host that is connected to two LANS, and an organisation
that has two ISPs.
So, unless there's some routing revolution, you're just going to have
to learn to deal with multiple addresses, and unless LL addresses go
away, you're also going to have to deal with scoped addresses.
| so that collisions are still likely whenever sites merge.
I think I'd say possible, rather than likely. But of all the problems,
this is the one that bothers me least - sites aren't required to merge
after all (when that does get to be a requirement, it is likely that
far more significant changes are made than just "let those two sites have
unified site local addresses). After all, you want to abolish the things
completely - if it would be acceptable to not have them (and do remember,
no organisation is going to be compelled to use them) then worrying about
how to unify if they do exist them can't be high on anyone's agenda can it?
That is, merging site locals would only be an issue of site locals are
actively being used - if they're useless, and problematic, as you're
claiming, then surely people won't be using them (the "I can't get enough
address space" excuse for using 1918 addresses won't exist after all).
If no-one uses them, merging won't be a problem, and nor will any of the
other issues you see, surely?
So, if you're worried about this, then you must be assuming that they
will in fact be used - which to me means, that you can see that there is
actually a demand for something to solve the problems that (apparently)
only SL addresses currently can do (that's obvious, as if there was some
other available solution, then people would use that, rather than these
problematic SL things, wouldn't they???)
So...
| unfortunately, many important considerations were ignored in that design.
Let's see your design that handles the issues that you must agree that the
users need solved, and which actually takes note of all of those other
considerations.
Until we have that, and agree that it is a better design, let's just agree
that there really is no choice - we either keep SLs in the design (however
far from absolute perfection that actually are) or the users will invent their
own variations, in a thousand different ways - which I really can't believe
that you consider a preferable answer.
kre