What is a reasonable range for global BGP table size?

Thu Jul 18 21:25:48 UTC 2002

I still don't see where the excess 20K routes come from. Could these be
internal routes from an iBGP ?

BTW, we have similar histograms plotted on
http://www.multicasttech.com/status/cidr.html and given in
http://www.multicasttech.com/status/histogram.cidr.bgp

# cidr_histogram  Unicast  Prefix Size Histogram
# cidr_histogram  Prefix Size | Number of Prefixes | Number of CIDR 
Holes | Number of Addresses | followed by relative PER CENTAGE in order
# cidr_histogram size  # prfx # holes   # addr % prfx % holes % addr
# cidr_histogram
  cidr_histogram   1       0       0          0    0.0     0.0    0.0
  cidr_histogram   2       0       0          0    0.0     0.0    0.0
  cidr_histogram   3       0       0          0    0.0     0.0    0.0
  cidr_histogram   4       0       0          0    0.0     0.0    0.0
  cidr_histogram   5       0       0          0    0.0     0.0    0.0
  cidr_histogram   6       0       0          0    0.0     0.0    0.0
  cidr_histogram   7       0       0          0    0.0     0.0    0.0
  cidr_histogram   8      20       3  335544280    0.0     0.0   28.0
  cidr_histogram   9       6       1   50331636    0.0     0.0    4.2
  cidr_histogram  10       7       2   29360114    0.0     0.0    2.5
  cidr_histogram  11      12       1   25165800    0.0     0.0    2.1
  cidr_histogram  12      36      12   37748664    0.0     0.0    3.2
  cidr_histogram  13      87      28   45612882    0.1     0.0    3.8
  cidr_histogram  14     235      59   61603370    0.2     0.1    5.1
  cidr_histogram  15     415     102   54394050    0.4     0.2    4.5
  cidr_histogram  16    7270     851  476432180    6.4     1.4   39.8
  cidr_histogram  17    1452     475   47576232    1.3     0.8    4.0
  cidr_histogram  18    2647     846   43363154    2.3     1.4    3.6
  cidr_histogram  19    7672    2205   62833680    6.8     3.7    5.2
  cidr_histogram  20    7429    2680   30414326    6.6     4.5    2.5
  cidr_histogram  21    5212    3146   10663752    4.6     5.3    0.9
  cidr_histogram  22    7929    5330    8103438    7.0     9.0    0.7
  cidr_histogram  23    9682    6619    4937820    8.6    11.2    0.4
  cidr_histogram  24   62823   36537   15957042   55.5    61.8    1.3
  cidr_histogram  25      54      51       6804    0.0     0.1    0.0
  cidr_histogram  26      25      23       1550    0.0     0.0    0.0
  cidr_histogram  27      31      31        930    0.0     0.1    0.0
  cidr_histogram  28      30      28        420    0.0     0.0    0.0
  cidr_histogram  29      16      16         96    0.0     0.0    0.0
  cidr_histogram  30      79      76        158    0.1     0.1    0.0
  cidr_histogram  32      31      29         31    0.0     0.0    0.0

Note that you (or route views) sees 10K more /24 than we do, 3K more 
/23's, etc.

Regards
Marshall

Jared Mauch wrote:

> On Thu, Jul 18, 2002 at 11:11:18AM -0600, Kris Foster wrote:
> 
>>That number is still too high since some people are advertising their /25 to
>>/32 prefixes to the route-views box..
>>
> 
> 	true, but unless you do ingress filtering of your upstream
> (which most smaller ASes do not do) your numbers may be
> wrong.  People also leak internal routes to route-views at
> times also i've noticed.
> 
> 	(still talking about the same route-views snapshot)
> 
> count netmask
> % cut -d: -f2 oix.home_as.out | cut -d/ -f2 | sort -n | uniq -c
>   25 8
>    6 9
>    7 10
>   12 11
>   36 12
>   99 13
>  269 14
>  514 15
> 9764 16
> 1537 17
> 2778 18
> 8378 19
> 8131 20
> 6075 21
> 9949 22
> 12258 23
> 73921 24
>  468 25
>  419 26
>  354 27
>  378 28
>  241 29
>  225 30
>  105 32
> 
> 	- jared
> 
> 
>>Kris
>>
>>
>>
>>>-----Original Message-----
>>>From: Jared Mauch [mailto:jared at puck.Nether.net]
>>>Sent: Thursday, July 18, 2002 12:47 PM
>>>To: Robert Boyle
>>>Cc: nanog at merit.edu
>>>Subject: Re: What is a reasonable range for global BGP table size?
>>>
>>>
>>>
>>>	I was going off my data analysis of
>>>route-views data.
>>>
>>>wc -l oix.home_as.out
>>>  135949 oix.home_as.out
>>>
>>>	this file has prefix:home_asn
>>>
>>>	(where home_asn is the last asn in the as_path.  prefixes
>>>with inconsistent home_as will appear twice.  this may be 
>>>cause of some
>>>of your confusion.  eliminating those brings it to 120131 prefixes)
>>>
>>>	- jared
>>>
>>>On Thu, Jul 18, 2002 at 12:37:09PM -0400, Robert Boyle wrote:
>>>
>>>>At 11:26 AM 7/18/2002 -0400, you wrote:
>>>>
>>>>>Hmm.
>>>>>
>>>>>We don't filter, and
>>>>>
>>>>>112942 network entries and 391859 paths using 25288182 
>>>>>
>>>bytes of memory
>>>
>>>>We don't filter either and...
>>>>
>>>>117800 network entries and 339843 paths using 23660948 
>>>>
>>>bytes of memory
>>>
>>>>
>>>>"about 135k prefixes last i checked." is not what we see 
>>>>
>>>here from any of 
>>>
>>>>our upstreams.
>>>>
>>>>
>>>>-Robert
>>>>
>>>>
>>>>
>>>>
>>>>Tellurian Networks - The Ultimate Internet Connection
>>>>http://www.tellurian.com | 888-TELLURIAN | 973-300-9211
>>>>"Good will, like a good name, is got by many actions, and 
>>>>
>>>lost by one." - 
>>>
>>>>Francis Jeffrey
>>>>
>>>-- 
>>>Jared Mauch  | pgp key available via finger from jared at puck.nether.net
>>>clue++;      | http://puck.nether.net/~jared/  My statements 
>>>are only mine.
>>>
>>>
> 

-- 
                                  Regards
                                  Marshall Eubanks

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