[110072] in North American Network Operators' Group
Re: What is the most standard subnet length on internet
daemon@ATHENA.MIT.EDU (Grzegorz Janoszka)
Tue Dec 23 08:49:33 2008
Date: Tue, 23 Dec 2008 14:49:00 +0100
From: Grzegorz Janoszka <Grzegorz@Janoszka.pl>
To: Nathan Ward <nanog@daork.net>
In-Reply-To: <41036FF1-4200-4D16-B69D-1D3A91DDFCC1@daork.net>
Cc: nanog list <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
Nathan Ward wrote:
>>> Let me rephrase; Are there people who are filtering /24s received from
>>> eBGP peers who do not have a default route?
>>
>> of course.
>
> Curiously, it was really meant as a rhetorical question where the answer
> was "no".
>
> Why are people doing this? Are they lacking clue, or, is there some
> reasonable purpose?
Memory mostly I think. /24 prefixes are ~ the half of all prefixes, but
they cover only a small percent of the address space.
If your router has > 6 full BGP sessions, you can filter /24 on half of
them, your memory usage will drop significantly.
--
Grzegorz Janoszka
Leaseweb
