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Date: Tue, 08 Jan 2013 12:42:30 +0000
From: Karl Pielorz <kpielorz_lst@tdx.co.uk>
To: Gleb Smirnoff <glebius@FreeBSD.org>
Subject: Re: Arp table size - any adjustments?
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--On 13 December 2012 15:33 +0400 Gleb Smirnoff <glebius@FreeBSD.org> wrote:

> Nope, there is no autotuning here yet.
>
> The hash table size is hardcoded in sys/net/if_llatbl.h. The name of
> constant is LLTBL_HASHTBL_SIZE.

Default is 32, which is even commented with "/* default 32 ? */" - I found 
another thread via Google which discussed upping this to 512 for a 'Generic 
Box'

For a router that has 4k+ ARP entries, any recommendations? - e.g. 1024? / 
2048?

2048 seems sensible considering the other thread recommended it should be 
1/4 the table size (so, 4k entries in arp table = 2k hash?) or even 4k to 
cover expansion.

-Karl