Subject: RE: AN interesting article. FYI... contd

From: Dan Lanciani <[email-masked]>
Date: Fri, 27 Aug 1999 16:13:34 -0400 (EDT)

I must play devil's advocate here.

"Mike Zintel (Exchange)" <[email-masked]> wrote:

|It's helpful to contrast an ideal IPv6 world with today's world of DHCP'd,
|IPCP'd, NAT'd, tunneled and proxied TCP/IP.

In today's world, at least some end users (i.e., those who got in before
so many addresses became "reserved") have stable, portable IP address space.
Under IPv6, no end user will have stable or portable IP address space.  This
may seem like a good equalizer to the have-nots, but it isn't a feature for
the haves.

In today's world, at least some end users can still take advantage of what
was once seen as a very important characteristic of the tcp/ip protocol:
as long as you control the end points, it can be made arbitrarily tenacious
independent of the reliability of the intermediate routers (assuming you
don't have a total, permanent failure of course).  Under IPv6, any active
tcp/ip connection is always at the mercy of renumbering.  Saying that
nobody expects tcp/ip connections to be reliable outside of the intranet
(as I have seen expressed here from time to time) ignores all those users
who expect just that.  Assuming that the problem will be easily solved by
adapting tcp/ip to survive renumbering is, I think, minimizing a very tricky
technical task.  (And of course, it does nothing for application-level
address knowledge.)  Any complete solution that renders tcp, udp, and
everything above largely independent of short-term address persistence
(perhaps by creating a new class of cookie that effectively becomes the
"first-class citizen" of identify) will make IPv6 addresses very different
animals from IPv4 addresses.  It may even make IPv6 addresses (at least in
the sense that they are administratively allocatable entities) superfluous.
This last is actually technically interesting, but it would obviate the need
for all the address allocation policy that we know and love, and things
don't seem to be moving it that direction.  And besides, there has to be
some pseudo-stable address space if only to provide a measure for billing...

In today's world, a NAT user has complete control of the stability of its
internal addresses and can hide its internal structure more-or-less
completely.  Under IPv6, the stability of the internal addresses (which
are then, granted, at least globally routable) is dependent on every
provider above the user.  Moreover, the internal structure is completely
exposed.  This is great for the ISP who wants to bill per-host, but of
little benefit to the end user.  Naturally, there will be IPv6 NAT boxes
(in several translation flavors) and I'll bet they will be used in V6<->V6
mode just to get the structure-hiding and firewall features.  But there's
not much point comparing NAT to NAT in this context...

|Part of the problem selling IPv6 is the success of the address shortage
|work-arounds.

We are observing evolution in action.  Apply the pressure of an address
shortage (even if artificial) and the market will adapt, but perhaps
not in the way some would like.  It would be neat if you could make
addresses valuable (dollar-wise) and then create a lot of wealth by
expanding the address space, but the market doesn't always work that
way. :)

|Call attention to the usability and administration costs of
|these solutions.

The problem here is at least three-fold.  First, a lot of these work-arounds
work very well and their administrative costs even over the life of a company
may not approach the cost of switching to IPv6 (and IPv6 solutions are
not without their--hard to characterize--administrative costs).  Second,
some of these work-arounds offer features above and beyond expanding apparent
address-space.  These features will still be required with a switch to IPv6 but
all the code will be new and untested.  More overhead tipping the balance away
from IPv6.  Finally, IPv6 simply does not offer anything resembling an expanded
IPv4 address space.  IPv6 addresses are qualitatively very different from IPv4
addresses.  IPv6 addresses are closer to DHCP'd or even NAT'd addresses than
they are to stable IPv4 addresses, and IPv6 features tend to be of more benefit
to ISPs than to end users.  Until all the collateral work has been done to make
an IPv6 address a functional drop-in replacement for an IPv4 address in whatever
applications are of interest to a particular organization, there may be little
incentive for that organization to switch.  Even when this is done, IPv6 will
have to bring more than parity to the table.

|One serious problem still largely unsolved in today's world is the absence
|of a unique identifier that can be used initiate a connection from the core
|network to a (PPP or DHCP) transiently connected end node. This is part is a
|result of PPP/DHCP enabled address pooling.

This problem is currently addressed with dynamic DNS.  IPv6 will presumably
rely on the same mechanisms, perhaps more so since IPv6 addresses are less
stable...

				Dan Lanciani
				[email-masked]
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---

From: Peter Tattam <[email-masked]>
Date: Sat, 28 Aug 1999 13:35:40 +1000 (EST)

Dan and others have touched on an important issue, and that is Ipv6 is likely
to get (and has already been) grilled heavily by the press.  My own personal
experiences with the press reflect similar attitudes to the one by the reporter
in question.

We need to keep an open mind about these aspects and should be focusing on
mechanisms in IPv6 that give good incentives for organizations to upgrade to
IPv6.   

The promotion of transition mechanisms should be taking a fairly high priority,
as should ease of use of the new protocol.  Instead I perceive opinions that
maybe shun or discredit transition solutions, and policies of aggregation and
renumbering that push us into uncharted territory.  To the average outsider
from the IPv6 scene, these would be enough of a disincentive for them to
transition their infrastructure to Ipv6 despite their current problems with
Ipv4 address lifetime extensions.

Many of the people who have the final say on decisions on whether to switch to
Ipv6 will unfortunately listen to the cries of the opponents, and will have a
hard time fathoming the perceived benefits and difficulties IPv6 transition
will bring them.

With that in mind, our (TSI's) focus is on demonstrating how easy it is to
enable a client and a network to IPv6 and let them see the benefits for
themselves.  Mind you, this is not as easy as it sounds, and there are still
engineering hurdles that I have been frustrated at finding solutions to.

Also, it may boil down to what we perceive as the eventual goal of IPv6.
If it remains, as I believe has been, as merely an engineering solution to
solve a specific set of problems, it will not make much headway.  

If it instead becomes "a way of life", then we may have more of a chance.  This
would mean that the IPv6 team will then need to focus on a more holistic
approach to doing networking, with a common set of key goals.  Those goals will
have to answer many more powerful issues than the existing IPv6 solutions
address.   I and others would tend to think that there isn't quite enough
benefit from moving to IPv6 that would tip the scale for the CEO's and CIO's of
this world.   There need to be some bolder and more decisive goals for the
world to take note and start agreeing with us.

I feel that a goal of being able to contruct a network out of raw components
and simply connect them together with the absolute minimum of configuration
would be a worthy one for the "IPv6 way of life" to embrace.  This would have
to be applied in a totally holistic approach from the appliances and
workstations to intermediate routers and potentially right into the main core.
We already have systems in hardware that you simply plug this bit into that bit
and it just works.  Face it people, configuration and maintenance of networks
is probably one of the biggest hits and a growing one for every IT related
company in the world.  If we could demonstrate that Holy Grail through the
"IPv6 way of life"  many many more prominent decisions makers would take
serious notice of IPv6.

The internet has grown too large for people to tinker any more, and it needs to
move to a higher plane of self management.

In a world where computing is moving rapidly to the appliance model, "the Ipv6
way of life" may be the only way that reality could be achieved.

Peter

--
Peter R. Tattam                            [email-masked]
Managing Director,    Trumpet Software International Pty Ltd
Hobart, Australia,  Ph. +61-3-6245-0220,  Fax +61-3-62450210