Subject: Re: [rrg] Constraints due to the need for widespread voluntary adoption

From: [email-masked] (Noel Chiappa)
Date: Tue, 1 Dec 2009 13:30:05 -0500 (EST)

> From: Robin Whittle <[email-masked]>

    > I wrote about this in April and updated the text after some helpful and
    > generally positive feedback:
    >   http://www.firstpr.com.au/ip/ivip/RRG-2009/constraints/

I only have time for a quick skim of this (_way_ behind :-), but the list of
points generally looked pretty good to me.

My only concern was that, in toto, the entire list might be the equivalent of
asking for a car that goes 400 KPH and gets 500 MPG (or whatever the
equivalent is in kilometres per liter, sorry everyone in the rest of the
world :-), i.e. we can't have all of them at the same time. So it might be
that we'd have to prioritize some as being more important than others.

	Noel

---

From: Robin Whittle <[email-masked]>
Date: Wed, 02 Dec 2009 10:26:26 +1100

Short version:   I think constraints 1 to 7 are absolute.  If the
                 best solution can't fully meet constraints 8, 9 and
                 10, then maybe it could still solve the routing
                 scaling problem to a worthwhile degree.

Hi Noel,

> that we'd have to prioritize some as being more important than others.

I think constraints 1 to 7 are absolute.  Here are my thoughts on 8,
9 and 10.

If the solution did not meet constraint 8, this means that could
still be highly attractive for many smaller networks which haven't
yet started using the unscalable approach to multihoming etc. (PI
space advertised in the DFZ), but would be either less attractive or
not attractive at all for those networks which already have their own
PI space.

For instance, maybe the best proposal wouldn't be adopted widely by
networks with PI space, so the current number of DFZ routes would not
decline, but at least it would not grow as fast as without the
solution - and millions of smaller networks will get multihoming,
portability and TE on a scalable basis.

Constraint 9 - not compromising security, robustness or performance -
 is a sliding-scale affair.  Ideally there would be no compromise.
If the best we can do involves some compromise, then perhaps we can
still get wide enough adoption to solve the problem and provide
multihoming etc. for the large number of smaller networks which can't
get it now.

There is an argument that smaller networks, which couldn't afford PI
space, even it was available (and it is for IPv6) wouldn't be
contributing to the scaling problem anyway, and don't have any
alternative for multihoming etc. than to adopt the scalable solution.
 In that case, *maybe* they would accept some degradation in
security, robustness or performance.

If and when IPv6 or some other addressing scheme becomes useful for
end-user networks as an alternative to IPv4, then I think it can be
assumed that the high costs of PI space, and of advertising it, which
are the pattern with IPv4 won't be replicated with IPv6 or whatever.
 So in a broader architectural sense, beyond IPv4 (I am yet to be
convinced we ever will move beyond IPv4, except for cellphones), we
can't rely on the unscalable BGP approach to multihoming etc. being
"expensive".

I think that any substantial perceived degradation (whether real or
not) will make it impossible to gain wide enough adoption as long as
the unscalable alternative is available to each end-user network.

If the scalable solution offers second-rate performance compared to
conventional PA or PI space, or is perceived as being unsuitable for
large networks, then many small networks will avoid it - especially
smaller networks which plan to be larger in the future.

Constraint 10 is a sliding scale one too.  Widespread voluntary
adoption could best be achieved if there was no need for any internal
router upgrades or replacements.  However, for small networks, there
may be only one router and its cost may be so small as to present
little impediment to widespread adoption.   For larger networks,
having to replace many or all internal routers - presumably expensive
ones - would surely be a barrier to voluntary adoption which would
make it much more difficult to wean these networks from their current
unscalable multihoming and portability arrangements.

  - Robin

---

From: Dae Young KIM <[email-masked]>
Date: Wed, 2 Dec 2009 18:50:07 +0900

Hi, Robin,

I do share your good intention with this list of constraints.

But, again, I have some worry that perhaps this list will be falsely used to
effectively reject most of proposals. Too many ideal assumption, perhaps
with this list of constraints.

Our patient is dying, in any moment. There's no way of saving him by surgery
without causing pain, real severe pain. He won't voluntarily accept the
pain.

On Wed, Dec 2, 2009 at 8:26 AM, Robin Whittle <[email-masked]> wrote:

> _______________________________________________
> rrg mailing list
> [email-masked]
> http://www.irtf.org/mailman/listinfo/rrg
>

-- 
Regards,

DY
http://cnu.kr/~dykim

---

From: Robin Whittle <[email-masked]>
Date: Thu, 03 Dec 2009 13:27:31 +1100

Short version:   Some people are uncomfortable about the
                 constraints perhaps precluding any proposal from
                 being viable.  Can anyone suggest why this
                 statement of the constraints is incorrect?

                 I think at least two proposals meet the constraints.

Hello Dae,

Thanks for your message, in which you wrote:

> But, again, I have some worry that perhaps this list will be falsely
> used to effectively reject most of proposals. Too many ideal assumption,
> perhaps with this list of constraints.

OK - which of the constraints listed at:

do you think are not realistic, bearing in mind the recent messages
about 8, 9 and 10 not being absolute?

This text is meant to reflect reality.  It is not my "ideal" list of
constraints - ideally there would be no such constraints.

I am happy to modify or annotate the list if you can think of
corrections or some circumstances in which a constraint would not apply.

If these constraints are real, then proposals which don't meet all
the absolute constraints should be rejected - or put on the
back-burner for some future scenario in which the constraints no
longer apply.

If all the proposals fail to meet the constraints, then we are in
trouble.  We only need one proposal which meets them, but ideally
there should be a few to consider.  Meeting these constraints
regarding voluntary adoption doesn't indicate anything about the
other merits of the proposals.

I believe APT and my own proposal Ivip fully meet these constraints.

I think LISP-NERD could meet them, but it doesn't scale well.  It
would always be better to use local full database query servers, as
does APT and Ivip.

LISP-CONS, LISP-ALT and TRRP can't fully meet the 9th constraint -
that of not degrading security, robustness or performance.  This is
because they use a distributed global query server system which means
that ITRs must often wait significant times - such as a fraction of a
second to a second or two - before they can send the first packets in
a new communication session.  This means dropped packets and slower
starts to many sessions.  Also, if the map query packet or its reply
are lost in their potentially very long paths across the globe, then
it may take the ITR two to four seconds to resend the query and
receive a mapping reply.

> Our patient is dying, in any moment. There's no way of saving him by
> surgery without causing pain, real severe pain. He won't voluntarily
> accept the pain.

In which case the patient will die, or reach a point where the
surgery looks like the less painful option.

But I think the patient is not going to die any time soon.  The
number of routes in the IPv4 DFZ is growing inexorably, but not rapidly:

   http://bgp.potaroo.net

The doubling time is about five years.

Meanwhile, many smaller networks which want and need multihoming,
portability and inbound TE are not able to get it.  So the situation
is bad, but the Internet still works.  The cost of the growing number
of DFZ routes burdens all ISPs and multihomed end-user networks.  It
also makes it somewhat harder for new ISPs to be established by
pushing up the price of the multihomed DFZ routers which every ISP
needs.  The growing number of routes in the DFZ also contributes
somewhat to difficulties with the DFZ routers being slower in
converging on a new set of paths in the event of an outage.

The Internet and its interdomain routing system is a growing system,
with plenty of money flowing into it.  Lack of scalable routing won't
kill it - it just adds to costs, reduces the ability of end-user
networks to have multihoming etc. and makes it harder to establish
new ISPs (which reduces competition between ISPs).

The surgery doesn't necessarily involve pain.  If APT, Ivip and
perhaps some yet-to-be developed proposals meet these constraints,
then there isn't any "pain" to rule out widespread voluntary adoption.

A successful proposal has to be highly attractive.  One way of making
them attractive and generate revenue is to use them as part of a new
approach to mobility.  Any of these core-edge separation schemes
(LISP-NERD/CONS/ALT, APT, Ivip or TRRP) could be used for a new kind
of mobility, for IPv4 or IPv6, using the TTR (Translating Tunnel
Router) approach:

I think this is so attractive, that you could sell this service,
complete with a system like APT or Ivip, irrespective of whether
there were IETF RFCs for the systems, and irrespective of whether you
wanted to solve the routing scaling problem.  The mobile node gets
its own IP address (or prefix in IPv6) and can use it on any care-of
address, including behind one or more layers of NAT and including the
use of traditional MIP techniques.  Path lengths are generally
optimal or nearly so, and the mobile hosts communicate fine with
ordinary hosts.

I would be worried if all of the proposals failed to meet what appear
to be the real constraints imposed by voluntary adoption.  However,
since I believe that two meet them well, then I am optimistic about
the problem being solved.

Judging by the slow progress since the RAWS workshop in October 2006,
I think it may take another 5 or 10 years.  I think it needs to be
done in a way that facilitates maximal usage of IPv4 address space -
since we are all dependent on IPv4 and I don't see this changing in
the foreseeable future.  There's no tearing hurry about the IPv6
routing scaling problem, but hopefully something similar to the IPv4
solution will work well for IPv6 too.

  - Robin

---

From: Dae Young KIM <[email-masked]>
Date: Fri, 4 Dec 2009 08:46:15 +0900

> solution will work well for IPv6 too.
So, it pretty much seems that we're practically left with only two
candidates alive by now. All others practically gone. Let alone any other
new coming proposals, considering that most of those renowned old proposals
even have not survived.

I only have to read two proposals. Thank you for saving my time.

-- 
Regards,

DY
http://cnu.kr/~dykim

---

From: Robin Whittle <[email-masked]>
Date: Fri, 04 Dec 2009 11:51:56 +1100

Hello DY,

You wrote:

> candidates alive by now. All others practically gone. Let alone any
> other new coming proposals, considering that most of those renowned old
> proposals even have not survived.
> 

I am not tying to discourage you from reading anything.  If you
disagree with anything I wrote, please write in detail about what you
believe and why - that will be a good discussion.

Likewise, if you think my attempt at listing the constraints is
unrealistic, please sugggest improvements.

  - Robin

---

From: Dae Young KIM <[email-masked]>
Date: Fri, 4 Dec 2009 10:05:12 +0900

OK, in fact, I do know all yours are for good intention.

Only that your list of constraints would be used as a kind of guiding
lights. Not as an absolute measure to cut off branches.

Mostly, your constraints are common-sense, well-intended. Good to bear in
mind. But, let's leave room where we have to inevitably or for good
persuading reason break the walls and not to meet to some or quite a number
of them.

-- 
Regards,

DY
http://cnu.kr/~dykim

---

From: Robin Whittle <[email-masked]>
Date: Sat, 05 Dec 2009 12:08:05 +1100

Short version:    If anyone can think of exceptions to these
                  constraints, then please describe them.

                  My assumption about "voluntary" adoption involves
                  the IPv4 Internet operating without disruption or
                  neglect.

Hi DY,

In reply to your message:

  http://www.ietf.org/mail-archive/web/rrg/current/msg05449.html

regarding http://www.firstpr.com.au/ip/ivip/RRG-2009/constraints/ you
wrote, in part:

> Mostly, your constraints are common-sense, well-intended. 

I don't "intend" there to be any constraints.  I am trying to
describe the constraints which really exist.  I would be happiest if
there were no such constraints.

> Good to bear in mind. But, let's leave room where we have to 
> inevitably or for good persuading reason break the walls and
> not to meet to some or quite a number of them.

OK - maybe someone believes there is a solution to the routing
scaling problem which violates one of these 7 statements of absolute
constraint due to the need for voluntary adoption.  Then, assuming
they are correct (which we couldn't tell except by building their
solution and observing it really does solve the problem) then one of
these must be true:

  a - One or more of these statements about absolute constraints
      is incorrect.

      If so, then the person with the proposal should be able to
      explain why this is so.  Please do - I will change or annotate
      the page.

  b - Their proposal doesn't rely on voluntary adoption.

      That's fine, but the person should be able to show how their
      solution is going to be widely enough adopted without relying
      entirely on voluntary adoption.

I am assuming that "voluntary" means that end-user networks, with
free choice, find it attractive to adopt the new system in terms of
the direct benefits it brings them - irrespective of whether they
know or care about routing scalability.

I am also assuming that the existing Internet - the IPv4 Internet -
continues to function as well as can reasonably be expected, without
neglect or disruption.

The rest of this message is something of a ramble . . .

If someone set fire to the IPv4 Internet and there was nothing left,
and everyone voluntarily adopted another Internet network, such as
IPv6 with scalable routing additions, this would arguably be
"voluntary adoption".  However, this is so improbable that we should
assume it will never happen.

Maybe some people think that IPv4 will get so overcrowded that large
numbers - such as a majority of - ordinary users will "voluntarily"
adopt IPv6 instead, when they can't get IPv4 space in any usable
form.  Apart from IPv6 being used for vast new cellphone networks
(and then, with some IPv4 space and support for IPv4 communications
via tunnelling) I can't imagine that happening in the foreseeable
future. [1]

In the long term - decades or centuries - arguably it would be best
if someone destroyed an overly restrictive and unsatisfactory system,
as IPv4 arguably is - to break our dependence and force everyone to
make the effort to adopt a better system.  Similarly it would be best
to destroy all the freeways in countries which drive on the right, so
they can be rebuilt so everyone in the world drives on the proper
side of the road.[2]  Likewise, all Windows machines would be retired
or destroyed and all cellphone, ATM and passenger jet cockpit numeric
keyboards would be rearranged to match the pattern used in computer
keyboards.[3]  We would all go cold-turkey on QWERTY keyboards and
switch to Dvorak keyboards or some other input device.

If anyone can think of a way of forcing the adoption of a scalable
routing solution, that would be great - we could design a better
Internet without these constraints.

  - Robin

[1]  After 13 years or so, I think there has been no adoption of
     IPv6 for real general Internet use, as a replacement for IPv4.
     I don't think there is a single ordinary Internet user who
     can use the Net like any other user, using only IPv6.  Some
     hosts can communicate with other hosts via IPv6.  Some IPv6
     enthusiasts use it for some communications, but even among
     enthusiasts, no-one can obtain the general utility of Internet
     communications enjoyed by all IPv4 users, without relying
     primarily on IPv4.

[2]  The proper side to walk on a track or road is the left,
     so most people have their most effective (right) arm ready to
     defend against oncoming bandits.  England and other countries
     followed this pattern with horses and then motor vehicles.

     Countries which drive on the right are the victims of
     French political correctness.  By the time of the French
     Revolution, the proletariat were walking on the right of the
     road - for their own safety due to the bourgeoisie driving their
     carriages on the left.  Come the Revolution, Political
     Correctness decreed that all people were proletariat and so
     should use the right side.

[3]  I recall reading that the rot set in with inverted numbers
     in phone keyboards when Bell Telephone asked its customers
     whether they wanted the 789 row at the top, or next to the
     0 key on the bottom.  They chose the bottom, since they
     were used to 9 being near 0 on a rotary dial phone, which is
     actually 10 pulses.