|
In einer eMail vom 21.06.2008 05:02:19 Westeuropäische Normalzeit schreibt
rw@firstpr.com.au:
Hi Tony
and Lixia,
You - or at least Tony - seem to be focusing on Getting It
Right for
the long-term: forever. This surely requires a
clean-slate
approach, with an entirely new routing and addressing
architecture.
Robin,
Yes !!! Be assured, myself, I am also and only focused on a long-term
solution, i.e. on a forever scaling solution.
At the same time I never was opposed to LISP or whichever map-encap
variant if considered to be a near-term interim solution.By other words:
map-encap is definitely not the longterm solution.
Instead I am convinced that topology aggregation will become the
longterm solution because it would scale even if the internet became
bigger than the network of our roads and streets.
For clarity reasons, I would like to ask for using a clean taxonomy.
Obviously, the term "topology aggregating prefixes" relates to
prefixes that summarize DFZ-routers' addresses. I think this only
fosters confusion, as all map-encap solutions are strictly in
opposition to a Topology Aggregating Routing Architecture.
Heiner
Yes, it would create an even more complex status quo, but that wouldn't
have mattered much
Perhaps you could start with IPv6 and make radical changes
along
the lines of GSE - but the result would be something quite
different
from IPv6 and would involve major changes to host stacks
and
applications, and I guess to TCP, UDP, SCTP etc.
The most
substantial solutions to the routing scaling problem
proposed so far
are:
LISP-NERD
LISP-ALT
APT
Ivip
TRRP
Six/One
Router
These are all intended by their developers to work for both IPv4
and
IPv6 as we know them today, without any host changes - other
than
perhaps minor optional changes to help work around moderate
inherent
performance problems in the pull-based map-encap systems. (I
think
Six/One Router can't work for IPv4, but it is intended
to.)
If you want the RRG to work solely on the Long Term Clean
Slate
approach, that is fine. While I (and I guess the other
map-encap
developers) would have something to contribute to that project,
it
is not an urgent project - unless perhaps you want it to be the
only
solution, which would make it much more urgent.
It would take
many years to devise the optimal Clean Slate approach.
As part of doing so,
you would need to incorporate transition
mechanisms which will enable the
majority of end-users to be
attracted to it - even in the early days when
few others use the new
system - rather than keeping going with the IPv4 (or
perhaps IPv6)
Internet.
Then it would take years to create all the
new protocols in detail,
write the software, get it built into existing
routers and hosts,
and to create new or radically re-written applications
for the new
system. (You would need to have a plan for motivating
application
programmers to make such huge investments, before many, or
any,
users used the new system.)
A Long Term Clean-Slate project
would be much more ambitious than
IPng - which involved minimal changes to
host stacks and
applications compared to what you need to do. 12 or
so years later,
that project has yet to achieve success.
I (and I
guess the other map-encap folks) think that the current
IPv4 situation is
important and urgent enough to warrant an IPv4
solution first, with a
similar, but not necessarily identical,
solution for IPv6 to be deployed
with less urgency. (I am not
suggesting the Net will melt-down in
2014, just that we are so far
from adopting IPv6, and that IPv6 isn't that
exciting, that we need
to keep IPv4 going for a lot longer so we have the
decade or so it
will take to devise something adoptable and long-term
scalable.)
All the map-encap proposals were described initially in
terms of
IPv4, with IPv6 details to follow later.
Maybe you
could get the RRG to devise a Long-Term Clean Slate you
consider promising
by March 2009, but I can't imagine you will
convince many people that what
the RRG devises is so promising that
no other line of research of action
needs to be taken.
I think you may be able to convince some IETF folks
a
"Clean-Slate-only" approach was the way forward. However, I
can't
imagine a sufficient number of end-users and ISPs would be
confident
that a completely clean-slate approach would be developed,
deployed
and very widely adopted in time to make it unnecessary to solve
the
IPv4 and perhaps IPv6 scaling problems directly.
The parlous
state of IPv6 adoption and of its transition mechanisms
shows how hard it
is to migrate from IPv4 to some new network which
requires different host
stack and applications, and which doesn't
connect directly to the IPv4
network.
Your new Clean Slate approach would be even harder to migrate
to,
since the host stack and applications would be totally
different,
not just marginally different - due to your need to devise
a
completely different set of clearly separated identifiers, locators
etc.
With only 9 months to go, I think the RRG needs to decide
ASAP
whether we is only working on a Long-Term Clean Slate approach,
or
whether we are pursuing several directions of research in
parallel.
Until this is settled, I think we will often be discussing
things at
cross purposes. For instance the recent exchange between
Bill and
Tony, where Bill talked about the Net as it is today, and what
is
required to support end-users who can't and won't change from
this
approach in the foreseeable future, while Tony seemed to
be
concerned only with the Long-Term Clean Slate approach.
I
suggested some text - points A, B and C - we might agree to
regarding
multiple paths of research in a recent message:
3 potential
consensus questions
http://psg.com/lists/rrg/2008/msg01574.html
Here are some other options
if C can't be agreed to:
D: No IPv4 solution - single Long-Term
Solution.
Devise single lasting solution which may be
applicable
as a major revision to IPv6 or which may require a
completely
new Internet architecture, protocols, applications
etc.
E: Devise an IPv6 solution but not an IPv4
solution.
Work on a solution for IPv6 without major
changes (this rules
out GSE or major changes to protocol,
stack, apps etc.)
As this work progresses, decide whether
this will be good enough
for the Long Term. Either
adapt it to be so, or regard scalable
IPv6 as the near-term
solution, while we devise a separate
Long Term Clean Slate
architecture.
F: No IPv4 or IPv6 solution. Devise purely a
Long-Term Clean Slate
solution, which has no basis in IPv4 or
IPv6.
I like Bill Herrin's comparison with the Manhattan
Project. What we
are trying to do is so far from a clear solution,
yet Something
Definitely Needs To Be Done and there are many uncertainties
about
what is technically possible, and what is adoptable in
various
time-frames.
I think there are too many uncertainties at
present not to pursue
multiple parallel streams of research.
Maybe
you only want to conduct the Long-Term stream on the RRG.
-
Robin
|