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Le 21/11/2014 10:08, Gert Doering a écrit :
> Hi,
>
> On Wed, Nov 19, 2014 at 06:31:56PM -0800, Ronald F. Guilmette wrote:
>> Of the remaining 235,061 route base IP addresses, fully 28,988 of
>> those (12.3%) are being announced by some AS other than the one
>> specified in the ripe.db.route file.
>
> To state something that might be obvious or not - for the same prefix,
> you can have multiple route: entries with different origin ASes, which
> makes sense when a network moves (add new route: object, start new
> announcement, eventually remove old route: object).  So, some of these
> might be perfectly fine, some might be forgotten (= a route: object with
> the proper origin AS exists as well), and some might just be legacy
> garbage - indeed.
>
>> Given the considerable number of routing anomalies revealed by my simple
>> experiment, I am inclined to wonder who is actually using all of that
>> route information in the RIPE DB, and what on earth they could be using
>> it for.
>
> We use it to build BGP filters for BGP customers.

So did I at previous employer's edge, for years and years.

>
>
> For those, the filter is build using the origin AS as key, so if there are
> additional route objects for the same prefix but with a different origin AS,
> our script won't see them, so it's "garbage that does not disturb anything".
>
> Of course, if the origin AS doesn't match at all, customers' BGP announcements
> won't go out - and they usually notice that quickly and fix their stuff.

Yes, voilà, same.

>
>
> (Our upstream providers do the same thing for us, so it's used on a larger
> scale - unfortunately, not all large transit providers do that, some just
> take the money and look the other way)

Right, shared view.

Cheers,

mh

>
> Gert Doering
>         -- NetMaster

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