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Re: where the indirection layer belongs

2003-09-02 11:50:51
Robert,

Robert Honore wrote:
... As such, I can distinguish the following issues as aspects of the problem given all that was mentioned in this thread, the "solving the real problem" thread and the one on the IPv6 mail list about deprecating Site Local addresses and the usage of IPv6 Link Local addresses. They are as far as I can tell the following.

*    Stable (or reliable) end-point identifiers
* Resiliency of application (protocol) in the face of sudden IP address changes
*    Self-organised networks

I like your analysis very much.  Thank you for writing it up.

However, I also see a kind of causality here:  it looks to me
that stable end-point identifiers are mainly needed to make
applications survive IP address changes.  Dave Crocker's MAST
is a good example how you can do that without having stable
end-point identifiers.

On the other hand, security looks to me as a good reason for
having stable end-point identifiers.  If you can securely
recognize an end-point (with emphasis on the *re-* part of
re-cognize), you can develop trust.  Trust, in turn, is very
handy for lowering transaction costs.

With respect to stable end-point identifiers, we must in my opinion, still specify what we are calling an end-point and settle once and for all the question of whether an IP address is a suitable candidate for such an identifier.

Even facing the danger of opening yet another rat hole, in my
opinion we should not have a very strict definition for end-point.
That is, IMHO end-point should and could be a fuzzy concept,
somewhat like the concept of a site is today.

From my point of view, an end-point may be a process, a group of
processes, a host, or even a server cluster offering services as
a unit.  To me, it looks like fate sharing and common semantics
are the key points here.  An end-point should either work or fail,
it should not be usual for half of an end-point fail while the
other half is continuing.  An end-point should also be considered
at the application level as a single unit.

My question following from all that, are two. Is it worth it to attempt a solution to any of the aforementioned problems? If so, which one should we tackle first?

In my opinion, we clearly need solutions to all of these problems.
Furthermore, it looks like introducing stable end-point identifiers
to the stack almost automatically protect applications from
the changes of IP addresses.  I also tend to believe that stable
end-point identifiers may also help to build self-organized
networks.  However, IMHO the problem of self-organized networks
is more researchy in nature than the other two.

Now, even though I believe that we should solve the problems (and
apparently believe that there are sensible solutions), achieving
consensus on solutions that require architectural change may take
too long.  Hence, I also believe that we need some kind of a road
map, with some "temporary" or intermediate solutions along the way
to a more long-standing set of solutions.

--Pekka Nikander