Re: [Idr] draft-hares-deprecate-atomic-aggregate (was Re: Request for 2 drafts)

Jeffrey Haas <jhaas@pfrc.org> Tue, 14 March 2017 19:24 UTC

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Date: Tue, 14 Mar 2017 15:30:36 -0400
From: Jeffrey Haas <jhaas@pfrc.org>
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Subject: Re: [Idr] draft-hares-deprecate-atomic-aggregate (was Re: Request for 2 drafts)
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Sue,

On Mon, Mar 13, 2017 at 05:11:45PM -0400, Susan Hares wrote:
> I'd like to follow-up on our "clean up" the attribute area discussion. 
> 
> I've published: 
[...]
> 
> draft-hares-deprecate-atomic-aggregate-00  

I'd actually recommend against outright deprecating AA.  Mostly it'll lead
to confusion of compliant implementations of 1771/4271 without a lot of
benefit.

A significant amount of the controversy around the feature while
standardizing 4271 had to do with the rules by which AA was attached to
routes.  I suspect very few people besides Tony Li ever had a strong opinion
about the behavior, especially once we got beyond the BGP-3 transition.  
(And I wasn't there at the time.  The Tony observation is driven mostly by
him popping up a few years ago with a proposal that included AA behavior.)

The current behavior of 4271 with regard to AA is pretty mild: If you're
dropping out ASes from the path as part of aggregation, you SHOULD add this
thing.  If you see it, don't de-aggregate.

People generally don't de-aggregate magically these days and those who do
generally expect to have to be very careful.

The document that I thought was worth writing at some point, even if it only
was a draft and never got published, was a short discussion about the origin
of the feature, what its original intent was, what was broken about its
original rules to be attached and why we ended up where we did.  This is
arguably a history document intending to document a rather ugly bit of
living history that confuses newcomers to the protocol.

I'm happy to contribute to such a document.  But I don't recommend we
proceed down the path to deprecation.

-- Jeff