nested prefixes in Internet
vas at mpeks.tomsk.su
Mon Nov 21 14:08:07 UTC 2016
Niels Bakker wrote:
> >I have reports that in case (2), some operators (e.g. Rostelecom)
> >don't accept the /24 or even /23 prefix on the grounds that it is
> >part of a larger /19 route already present in the routing table.
> >Could they have a reason not to accept these more specific prefixes
> >other than a whim?
> If you announce a prefix you must deliver traffic sent to addresses
> covered by it. You don't go announcing 0.0.0.0/0 to your peers either.
> If a customer takes a /24 and announces it elsewhere, a transit
> provider runs the risk of accepting inbound traffic without having
> the possibility to bill their customer for it if it accepts more
> specifics from e.g. a peer.
That's all correct from the point of view of the provider annoncing
the /19 route, and should be their risk.
My question was however from a different perspective. If AS333
receives a /19 from AS111 and a /24 from AS222 (where AS222's /24 is
nested within AS111's /19), what reason might AS333 have to ignore the /24?
AS333 is not concerned with possible monetary relations between AS111
Victor Sudakov, VAS4-RIPE, VAS47-RIPN
sip:sudakov at sibptus.tomsk.ru
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