On Wed, 12 Oct 2022, Andrey Kostin wrote:
Matthew Petach писал(а) 2022-10-11 20:33:
My point is that it's not a feature of BGP, it's a purely human
convention,
arrived at through the intersection of pain and laziness.
There's nothing inherently "right" or "wrong" about where the line was
drawn, so for networks to decide that /24 is causing too much pain,
and moving the line to /23 is no more "right" or "wong" than drawing
the line at /24. A network that *counts* on its non-connected sites
being reachable because they're over a mythical /24 limit is no more
right than a customer upset that their /25 announcements aren't being
listened to.
IMO this line wasn't arbitrary, it was (and it still is) a smallest possible
network size allocated by RIRs. So it's just a common sense to receive
everything down to /24 to have the complete data about all Internet
participants.
Nope. I first did some work on this topic in early 2008 and remembered
writing a blog entry about it.
https://web.archive.org/web/20060926140659/https://www.ripe.net/ripe/docs/ripe-ncc-managed-address-space.html
RIPE, at least back in 2008, would allocate as long as /29 from several
/8s. I have no idea how many sub-/24 allocations they did or what the
recipients tried doing with the space. Even then, despite RIPE saying
"we'll allocate as long as /29", I set the filter cut-off [arbitrarily] at
/24 and made sure we had defaults pointing at ISPs that had "fuller"
tables.
And just for the record, despite having been bitten by it more than
once, I'm very much in the camp of "if you advertise a covering
aggregate, you're offering to get packets there, regardless of whether or
not more specifics exist." You have no business demanding what routes
someone else's network receives/accepts. All you can reasonably control
is what you advertise and what you accept.
----------------------------------------------------------------------
Jon Lewis, MCP :) | I route
StackPath, Sr. Neteng | therefore you are
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________
