Subject: Number of entries in routing tables

From: [email-masked]
Date: Wed, 15 Dec 1999 12:03:13 +0100

Hi all.
I have read that an inter domain router (connected to the big Internet) has a
routing table with 42000 entries (this value refers to the end of 1996). I would
like to know if it is possible to estimate the number of entries of an intra
domain router (that has only the knowledge of the destinations of the domain it
belongs to).
Tanks in advance!

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From: Bill Manning <[email-masked]>
Date: Wed, 15 Dec 1999 05:16:59 -0800 (PST)

% Hi all.
% I have read that an inter domain router (connected to the big Internet) has a
% routing table with 42000 entries (this value refers to the end of 1996). I would
% like to know if it is possible to estimate the number of entries of an intra
% domain router (that has only the knowledge of the destinations of the domain it
% belongs to).
% Tanks in advance!

The answer, as usual, is "it depends".  What is the "size" of your intra-domain?
In todays world, an interdomain router has just under 70,000 entries. 

--bill

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From: Bill Manning <[email-masked]>
Date: Wed, 15 Dec 1999 05:16:59 -0800 (PST)

% Hi all.

--bill

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From: Geoff Huston <[email-masked]>
Date: Thu, 16 Dec 1999 05:28:17 +1100 (EST)

There's a plot of the bgp table size on an hourly
basis since 1994 at http://www.telstra.net/ops/bgptable.html

As Bill points out, this data does depend on your location
within the network topology - the above url looks at the
world from the edge of AS1221.

  Geoff

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From: Geoff Huston <[email-masked]>
Date: Thu, 16 Dec 1999 05:28:17 +1100 (EST)

Geoff

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From: Vijay Gill <[email-masked]>
Date: Wed, 15 Dec 1999 13:16:47 -0500 (EST)

> domain router (that has only the knowledge of the destinations of the domain it

The answer varies on the size of the domain obviously.  For the most part,
it would consist of the global default free routing table + whatever the
internal routes amount to.  For some promising local ISPs, this number is
substantially over 100,000 entries.  For others, it is less.

/vijay

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From: Vijay Gill <[email-masked]>
Date: Wed, 15 Dec 1999 13:16:47 -0500 (EST)

/vijay