Smaller than a /24 for BGP?

John Levine johnl at
Wed Jan 25 03:53:58 UTC 2023

It appears that Chris J. Ruschmann <chris at> said:
>How do you plan on getting rid of all the filters that don’t accept anything less than a /24?
>In all seriousness If I have these, I’d imagine everyone else does too.

Right. Since the Internet has no settlements, there is no way to
persuade a network of whom you are not a customer to accept your
announcements if they don't want to, and even for the largest
networks, that is 99% of the other networks in the world. So no,
they're not going to accept your /25 no matter how deeply you believe
that they should.

I'm kind of surprised that we haven't seen pushback against sloppily
disaggregated announcements.  It is my impression that the route table
would be appreciably smaller if a few networks combined adjacent a
bunch of /24's into larger blocks.


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