Re: more-specifics in class B space?

[Marc Slemko <marcs () znep com>]

Cute.  So, further to this, I noticed that AS3356 (level3.net) was
advertising a route for 63/8, on and off.  Doesn't seem to be advertised
right now, but it comes and goes.  Example history entry from a couple of
minutes ago:

BGP routing table entry for 63.0.0.0/8, version 5217053
Paths: (14 available, no best path)
  Not advertised to any peer
  10764 5646 1239 3356 3356 3356 (history entry)
    206.220.240.223 from 206.220.240.223 (206.220.240.223)
      Origin IGP, localpref 100, external
      Dampinfo: penalty 464, flapped 1 times in 00:17:10
  5056 3561 3356 (history entry)
    167.142.3.6 from 167.142.3.6 (167.142.3.6)
      Origin IGP, localpref 100, external
      Dampinfo: penalty 467, flapped 1 times in 00:17:00
  267 1225 1325 1673 701 3356 (history entry)
    204.42.253.253 from 204.42.253.253 (204.42.253.253)
      Origin IGP, localpref 100, external
      Community: 267:1225 1225:80 1225:1325
      Dampinfo: penalty 732, flapped 2 times in 00:17:08
  1755 1800 1239 3356 3356 3356 (history entry)
    192.121.154.25 from 192.121.154.25 (192.121.154.25)
      Origin IGP, localpref 100, external
      Dampinfo: penalty 469, flapped 1 times in 00:16:50
  293 1800 1239 3356 3356 3356 (history entry)
    134.55.24.6 from 134.55.24.6 (134.55.20.229)
      Origin IGP, localpref 100, external
      Dampinfo: penalty 458, flapped 1 times in 00:17:24
  1849 702 701 3356 (history entry)
[...]

Why are they doing this?  Who knows, they don't respond to email.  But I
notice that they are advertising a whole bunch of /24s, /23s, and other
sub /20 blocks under 63/8.  What a great solution; "hey, people can't
reach us because we are advertising bogusly small blocks, so lets just
advertise an aggregate for the whole /8 to make sure everyone listens to
it".  Riiiiiiiiight.

The concept (ie. advertise an aggregate, even if it doesn't go to exactly
the right place, then also advertise more specifics; if someone filters
the more specifics, the aggregate will serve to get traffic to a network
that does listen to the more specifics) does often work as long as your
network topography is simple enough, it sure doesn't cut down on route
bloat.

Insert standard rant about having a clue before advertising routes, not
advertising bogusly small blocks, routing registries, etc.