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From: Catalin BOIE <util@deuroconsult.ro>
To: lartc@vger.kernel.org
Subject: Re: [LARTC] Filter huge number of hosts
Date: Tue, 11 Nov 2003 08:28:46 +0000	[thread overview]
Message-ID: <marc-lartc-106854052515419@msgid-missing> (raw)
In-Reply-To: <marc-lartc-106853777913308@msgid-missing>

On Tue, 11 Nov 2003, Peter Nelson wrote:

> Ok, I'm pretty new at this and am probably in a bit over my head, but I
> was looking for some pointers.  I want to classify and then prioritize
> traffic based on if it is to an Internet2 host, a host on campus or the
> general internet.  I got a dump from one of our campus's routers that
> classifies everything as either I2 or local, only problem is that it is
> ~8000 entries.  Now a lot of those entries can probably be combined down
> (for example a couple of sequential /24's).  My first question is does
> anyone have any script that you give it multiple netmasks and it
> combines it down to the simplest netmasks?  Now my second question is
> would using hashtables, maybe even nested ones be practical for this?
> This is how I'm thinking of hashing so far:
>
> Mask               hashes      children to check
> 0xFF000000:   100           most 50-500
> 0xFFFF0000:   3000         most <20, some 50-200
> 0xFFFFFF00:   8000         all < 10
>

You can link hashes to do what you want:
hash (made from first byte of the ip):
	01 -> another_hash_1
	10 -> another_hash_2

another_hash_1 entries (hash made from second byte):
	01 -> another_hash_on_level_2
	10 -> another_hash_on_level_2

and so on.


> Obviously hashing based on 0xFF helps, but it still has to go through up
> to 500 checks for somes hosts.  Once I hash based on 0xFFFF the worst
> case gets a lot better, and of course hashing on 0xFFFFFF makes almost
> perfect hashes.  Only thing is does a hash table lose it's point once
> you start indexing everything?  I was thinking maybe hashing based on
> the 0xFF and then from there making hashes based on 0x00FF (and then
> maybe an other layer of 0x0000FF).  I admit I really don't know all that
> much about the hashing algorighm and it's complexity so I don't know how
> to approach this.
>
> Thanks for any information,
> Peter Nelson
> _______________________________________________
> LARTC mailing list / LARTC@mailman.ds9a.nl
> http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
>

---
Catalin(ux) BOIE
catab@deuroconsult.ro
_______________________________________________
LARTC mailing list / LARTC@mailman.ds9a.nl
http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/

      parent reply	other threads:[~2003-11-11  8:28 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-11-11  6:48 [LARTC] Filter huge number of hosts Peter Nelson
2003-11-11  6:48 ` Peter Nelson
2003-11-11  6:48 ` Peter Nelson
2003-11-11  8:28 ` Catalin BOIE [this message]

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