Re: Route table growth and hardware limits...talk to the filter

["Andrew - Supernews" <andrew () supernews net>]

> > > > > "Forrest" == Forrest  <forrest () almighty c64 org> writes:

 Forrest> Sure, this would fail if a network decided to only announce
 Forrest> /24's for example without a larger aggregate, but how many
 Forrest> networks are really doing that?

More than you probably imagine.

Consider the following table:

      asn | count | c24  | c23 
----------+-------+------+-----
     9583 |  1100 | 1014 |  42
     7018 |  1140 |  764 | 125
    17488 |   560 |  557 |   0
    19916 |   568 |  532 |   6
      701 |   729 |  501 |  38
     1221 |   474 |  380 |  14
     1239 |   572 |  359 |  24
      577 |   417 |  337 |  19
      209 |   587 |  329 |  38
    17557 |   291 |  270 |   1
    10292 |   270 |  267 |   2
     4802 |   345 |  259 |  25
     6140 |   315 |  243 |  16
     4323 |   483 |  242 |  12
     7474 |   284 |  228 |   8
     2386 |   295 |  218 |   9
     3301 |   307 |  217 |  30
      702 |   392 |  206 |  34
     6746 |   279 |  200 |  41

In this, "count" is the number of prefixes originated by the AS that
are not covered by any longer prefix (without regard to origin); "c24"
is the number of those prefixes which are /24s; "c23" is the number
which are /23s. I've cut this table off at 200 - the total number of
uncovered /24 routes across all ASes is 51811.

Some of the above numbers would be worse if not for the presence of
over-large route announcements from other providers (for example,
Chinanet announce 125.96.0.0/14 even though 125.99.0.0/16 belongs
to hathway.net in India (AS 17488); approximately 230 _more_ /24
routes announced by Hathway are in this range).

-- 
Andrew, Supernews
http://www.supernews.com