Re: [nsp] BGP and Memory Requirements

From: Stefan Stefanov (sstefanov@orbitel.bg)
Date: Tue Sep 05 2000 - 09:12:26 EDT


Steve Lilley wrote:

>
> 3. Lastly, when applying BGP route filters (such as prefix
> filters) to incoming routes, aren't the filters applied as the
> routes are entered into memory? An example will help:
> shouldn't I be able to get away with MUCH less memory if I'm
> denying any routes larger than a /21 (i.e. permitting only
> /8 - /20, which gets the number of routes down to less than
> 18K BGP routes). If this is true, theoretically I should be
> able to use a trusty 2500 router with with 16MB of DRAM and
> (massive) filtering to take the full routing table and filter
> it down. Is this accurate? (Not that *I* would ever do such
> a thing with a 2500, but perhaps someone else on this list
> has?)
>

I can share some experience ot this. Works just fine with 2511 with 16
MB of ram. Of course when you have a bgp flap or a session reset the box
loooooooses steam, but it does work. Also you will have to point a
default route to one of your upstream as there are a lot of /24s
announced with no shorter prefix aggregate.

I wouldn't suggest this to anybody that means to do any business on the
internet, but I must admit - it does work.

-- 
Best Regards,

Stefan Stefanov CTO Orbitel - the Internet Company tel.: +359 2 980 90 77 fax: +359 2 980 42 58



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