Re: [p2pi] ALTO Information Export Service

John Leslie <> Wed, 29 October 2008 17:56 UTC

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Date: Wed, 29 Oct 2008 13:56:30 -0400
From: John Leslie <>
To: Reinaldo Penno <>
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Subject: Re: [p2pi] ALTO Information Export Service
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Reinaldo Penno <> wrote:
> On 10/29/08 9:47 AM, "Laird Popkin" <> wrote:
>> I don't understand why you say that "policy stated in ASNs is actively
>> misleading" though. Keep in mind that ALTO helps p2p networks find good
>> endpoints, not good routes - that's done by BGP, OSPF, etc., when
>> actually exchanging data.

   So far as I know, ALTO is completely unrelated to "finding good routes"
(which, BTW, is an issue possibly worth pursuing for multihomed users).

   While we hope that ALTO will help "find good endpoints", we're talking
about a (small) piece of ALTO only loosely related to that -- ISP policy.

>> selecting endpoints that have cheap routes between them makes it likely
>> that those cheap routes are actually used, but that's more a matter of
>> the lower layers working properly

   ... which is mostly the responsibility of the ISP...

>> than anything ALTO allows ISPs to directly express.

   It's premature, IMHO, to talk of what ALTO "allows".

> If you say "prefer this ASN" (since you are implicitly or explicitly for
> that matter) assuming that prefix 1.1.1/24 is hosted in that ASN but is
> actually not, then is misleading, yes?

   Any case where the publisher of information assumes one meaning while
the user assumes a different one, I would call "misleading".

   Reinaldo raises an issue -- whether an ISP might want to express an
opinion on whether CIDR blocks served by a particular AS are better or
worse than "average". I must admit (as an ISP) that I would not.

   But perhaps some ISP might -- and if so, they should be able to list
list opinions about ASNs separately from their own routing preferences.

John Leslie <>
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