RE: Stupid NAT tricks and how to stop them.

[jnc at mercury.lcs.mit.edu (Noel Chiappa)]

    > From: Scott Leibrand <sleibrand at internap.com>

    > NAT (plus CIDR) was the short-term solution,

Do note that CIDR was intended as a solution to a number of problems, not
just consumption of address space - like this one:

    > From: "Michel Py" <michel at arneill-py.sacramento.ca.us>

    > Especially now that the size of the routing table is not a problem
    > anymore.
    > ...
    > Also came memory issues with the global routing table. Some, including
    > me, said it was un-maintainable and would result in the Internet
    > collapsing. 

Since this old canard has resurfaced again, it's clearly time to drag out
some old messages, which I resend every couple of years, and send them
around yet again.

The executive summary is: The issue with routing table size (and why big
ones are Very Bad) is really not the size of the memory needed to hold the
table (which is a static thing), but the dynamics - i.e. things like
stabilization time after topology changes (and we have real problems there,
as all the fancy BGP route-flapping and dampening stuff attests).

For more, check out:

  Date: Sat, 9 Sep 95 17:22:17 -0400
  From: jnc at ginger.lcs.mit.edu (Noel Chiappa)
  Message-Id: <9509092122.AA27701 at ginger.lcs.mit.edu>
  To: big-internet at munnari.oz.au, com-priv at lists.psi.com
  Subject: Routing "experts"

[Apologies for the rather cranky/snide tone in this one - I was pretty
stressed out at the time.]

  Date: Thu, 22 Feb 96 12:44:33 -0500
  From: jnc at ginger.lcs.mit.edu (Noel Chiappa)
  Message-Id: <9602221744.AA28726 at ginger.lcs.mit.edu>
  To: karl at mcs.com
  Subject: Re: Last Call: Implications of Various Address Allocation Policies for Internet Routing to BCP
  Cc: cidrd at iepg.org, iesg at cnri.reston.va.us, ietf at cnri.reston.va.us

  Date: Thu, 22 Feb 96 12:44:33 -0500
  From: jnc at ginger.lcs.mit.edu (Noel Chiappa)
  Message-Id: <9602221744.AA28726 at ginger.lcs.mit.edu>
  To: karl at mcs.com
  Subject: Re: Last Call: Implications of Various Address Allocation Policies for Internet Routing to BCP
  Cc: cidrd at iepg.org, iesg at cnri.reston.va.us, ietf at cnri.reston.va.us

Someday I'll get energetic and turn these into a web page on the subject
(like my 'Will The Real "End-End Principle" Please Stand Up?' page). Alas,
no time at the moment.


No doubt some people, looking at the dates on these, will say "see, we've
gone ten years without running into the problems you mention, therefore they
don't exist". I must admit, I'm fairly amazed we haven't seen worse problems
with the routing because of table size. I can only attribute our lack of
observed problems to some very careful engineering by the ISP's.

	Noel

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