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Re: Pitfalls of annoucing /24s

  • From: Andrew - Supernews
  • Date: Wed Oct 15 18:02:39 2003

>>>>> "Phil" == Phil Rosenthal <[email protected]> writes:

 Phil> http://info.us.bb.verio.net/routing.html#PeerFilter

 Phil> That's how Verio does it, and I assume, that's how most people
 Phil> who filter by length do it as well.

We currently see 28804 /24 prefixes from our transits and peers which
are not more-specifics of another prefix that we see. (We see 127981
prefixes in total at the moment, so that's 22.5% of our table).
By comparison, we see 41066 /24 prefixes which are more-specifics for
another prefix, which is 32.1% of the table. In total, /24s account for
54.6% of the routes we see.

Of those 28804 isolated /24 routes, 946 are in "class A" space (0-127),
604 are in "class B" space (128-191), and the remaining 27254 are in
"class C" space (192-223).

The detailed breakdown by /8 is:

/8  |/24 routes | /24 routes
    |with aggr. | isolated    
====|===========|=============
   4         39          0
  12        722          0
  13          1          0
  15          6          0
  16          1          0
  17          2          0
  20          5          1
  24        706        117
  25          0          1
  32         94          0
  38         50          0
  40         23          0
  43          1          0
  44          2          0
  55          1          0
  57         11          0
  61        281         32
  62        360         82
  63       1897          8
  64       1693        102
  65       2012          2
  66       1918        250
  67        328         35
  68        381         13
  69        206         71
  80        218        197
  81        233         31
  82         15          4
 128         68         26
 129        149          3
 130         60          2
 131         63         13
 132         11          8
 134        107          5
 135          6          4
 136        176          2
 137         88         21
 138         65          1
 139         41          9
 140        131          1
 141        125         11
 142         92          1
 143         46          0
 144         79          7
 145         32          1
 146        145        124
 147         54         12
 148        287          4
 149         68         11
 150        120          1
 151         58          2
 152        219          2
 153         57          1
 154          7          0
 155        125          4
 156         53          5
 157         39          4
 158        139          1
 159        127         16
 160         43          3
 161         56         13
 162        182        180
 163         59          4
 164        111         14
 165        129         23
 166         87          9
 167        285         19
 168        163         12
 169         86          8
 170        298         17
 171          8          0
 192        582       4767
 193        744       1703
 194        672       1326
 195        637        639
 196        123        350
 198        972       2499
 199       1064       1763
 200       1136       1877
 201          1          0
 202       1810       2229
 203       1426       3775
 204       1471       1488
 205       1004       1028
 206       1630        453
 207       2116        370
 208       2532         31
 209       2294        485
 210        761        130
 211        320         60
 212        642        275
 213        611        360
 214         15          0
 215         22          0
 216       2048       1203
 217        629        424
 218         95         16
 219         33          0
 220        113          2
 221         13          0
 222          0          1

-- 
Andrew, Supernews