Subject: Re: [rrg] [Int-area] Please respond: Questions from the IESG as to whether a WG forming BOF is necessary for LISP

From: [email-masked] (Noel Chiappa)
Date: Thu, 22 Jan 2009 23:33:51 -0500 (EST)

> ... claiming that LISP is an appropriate solution to the problems
    > discussed at the IAB's October 2006 Routing and Addressing Workshop

Yakov, perhaps I'm confused, but I don't hear anyone claiming that LISP
should be 'anointed' as _the_ solution. In fact, it's explicitly being put
forward as an Experimental protocol.

What other path forward would you suggest for that work? Should LISP work not
be done in the IETF at all, but rather as a closed, private, outside effort?

        Noel
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From: [email-masked] (Noel Chiappa)
Date: Wed, 28 Jan 2009 12:44:11 -0500 (EST)

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

    > The LISP team should do detailed critiques of APT and Ivip as part of
    > convincing IETF folks of the merits of LISP-ALT.

Perhaps I'm confused, but I don't think the people working on LISP are trying
to "convince" the IETF as a whole of the "merits of LISP".

If some people out there in the Internet technical community think it looks
good, and want to work on it, run it, etc, that's great; but if other people
reach a contrary conclusion, and don't want to work on it, run it, etc (as is
their choice), that's fine too.

Sure, the people working on LISP would like to convince _some_ people that
it's a good idea, so they get i) some help working on it (as much remains to
be done), and ii) some places to deploy it (so some practical experience can
be gained, in seeing how well it works, what problems crop up in actual
service, etc), but that's a very different kettle of fish.

	Noel

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From: [email-masked] (Noel Chiappa)
Date: Fri, 30 Jan 2009 00:27:50 -0500 (EST)

>> I don't think the people working on LISP are trying to "convince" the
    >> IETF as a whole of the "merits of LISP".

    > I don't know the criteria is for creating a WG, but I guess the IETF
    > doesn't create them except for projects which have sufficient merit in
    > general

Sure - but that is not in contradiction to my statement above. The IETF has a
long history of creating WG's to work on different alternatives. In such
circumstances, WG's simply serve to create standards in an _open_ way; they
do not in any way imply any sort of official IETF preference.

    > I think the LISP team could best facilitate progress towards scalable
    > routing solutions by ... discussing in public why they think their
    > LISP-ALT approach is better than the alternatives.

The community has been discussing these issues for years, going back to
things like Multi6. It's been discussed to death already.

        Noel

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From: [email-masked] (Noel Chiappa)
Date: Sat, 31 Jan 2009 15:23:55 -0500 (EST)

> From: Christian Vogt <[email-masked]>

    > Any routing-scalability-related issues with BGP are not due to BGP
    > being push-based; they are due to frequent updates ... [this]
    > issue[] would go away in an address indirection architecture 

Not necessarily. It all depends on what functionality you're trying to get
out of that layer of binding, i.e. how often the average binding changes.
E.g. if you try and do some mobility through that binding layer (I'm not
saying we should, just as an illustration) that will radically increase the
rate/amount of updates.

On a more general note, I actually did some 'back of the envelope'
calculations a year or two ago, trying to decide whether to use push or pull,
and my recollection is that the update rate numbers (i.e. the control traffic
at each and every ITR) for push got fairly significant (in terms of the
number of updates per second) even with only moderate numbers of mapping
entries, and a fairly low assumed per-entry update rate (e.g. for provider
changes only).

Certainly, a full-push system is going to be distributing lots of mappings to
boxes that never use them - my guess was something in the 99% region, if not
much higher. (Long digression on the optimal mapping distribution system
omitted - the points you raise are certainly valid, but there are good points
on both sides, and I don't think the answer is clear-cut - if it were,
we probably wouldn't still be discussing it.)

Also, I'm not sure that for those working on LISP, ALT is the 'preferred'
long-range answer to the question of 'what does the mapping subsystem look
like'. I think the focus is on ALT at the moment in large part because it's
fairly easy to deploy, because it re-uses existing code. (Dino et al, please
correct me to the degree I am confused here.)

It might well make sense to transition to something else in the long run -
but then of course one has the transition issue to deal with, and from what
thinking I have put into that particular problem, it's more problematic that
some of the other long-term transition issues (e.g. to a different inter-xTR
packet format, etc). So that would argue to make replacement of that
subsystem priority number one...

	Noel