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Re: The Gorgon's Knot. Was: Re: Verio Peering Question
From: smd () clock org (Sean M. Doran)
Date: Fri, 28 Sep 2001 20:13:28 -0700 (PDT)


| Gimme a break.

Arm, leg, neck, spine or ego?

| s/the Sprint sales guy calls him and/he calls a Sprint sales guy who/

Clearly you have never ever tried to buy Internet stuff from Sprint!

| This would cause depletion of address space faster.

That sky hasn't fallen yet, despite the warnings since 1995.

| This does not address performance issues.

Nobody's perfect.

|  >    3. the maximum 254 things in the /24 can be renumbered
|  >           into small ISP's PA space and announced to UUWHO
|  >       with a constraining (set of) community(ies)
|  >
|  >       (NAT, incidentally, was also invented to make renumbering easier)
|
| All this does is swap the problem around, not solve it.

It does: traffic follows the aggregate to some part of the
         network that knows the secret exception and uses it,
even though it does not tell the rest of the world it is doing
so.  This network either needs to be big, or it needs to
leak a constrained more specific out to some of its neighbours,
which is a harder problem.

Essentially you are creating a wormhole, by analogy with a black hole.

"Ad hoc confederation of wormholers" either knows the more specific
prefix or follows the PI aggregate around to the small provider,
depending on connectivity.   Everyone else only knows the PI aggregate
and follows that.  If the following lands on any "ad hoc confederation
of wormholers" router, it follows the privately-known more specific.

Geoff Huston has been talking about a community which is useful
for doing the most common case of this kind of "ad hoc confederation"-making,
even though it's designed to deal with traffic engineering:
"announce this longer prefix to everyone receiving money from me".

| Why bother, when ISP-X down the street will "just do it"?

... which is ineffectual if people are doing filtering or
progressive flap dampening.

        Sean.


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