RES: [c-nsp] Different Traffic thru BGP links

[Rodney Dunn]

On Tue, Nov 23, 2004 at 11:35:41PM +0000, Ryan O'Connell wrote:
> On 23/11/2004 19:07, BRA-SAO-Tomaiz,Anderson Goncalves wrote:
> 
> >Well..I'm gonna try to explain better. Tell me if I'm not clear again ;)
> >
> >I have two internet peerings with providers A and B that I'm exporting their routes for all my customers (plus all the other internet routes). 
> >
> >Today one of my customers has one Link with me (let's call link01) that I'm exporting all the internet routes to him and I'm receiving his prefixes and announcing them to all my peerings (too many than providers A and B) and other customers. 
> >
> >This customer wants a new link (let's call link02) and he wants the traffic in the link02 will be only traffic between his AS and the AS from providers A and B. Remember, that I will keep exporting routes from this two providers to other customers. The link01 will have all other internet traffic with providers different from A and B.
> >  
> >
> 
> If you're trying to set up two links for differential billing purposes, 
> (E.g. transit costs $30/Mb/s 95th%ile, peering costs $10...) you're 
> probably better off setting up NetFlow and writing some scripts to 
> figure out traffic amounts that way. (BGP Accounting may also help, I've 
> not used it personally)
>
> Warning: Netflow eats CPUs for breakfast :-)

Can you be more specific with some baseline data you have? 

Netflow is done in the CEF path and is very optimized
for speed and on hardware forwarding platforms it's
done in hardware.  It does take more cycles on a software
forwarding platform and based on the hardware architecture
it may or may not decrease performance on hardware
based forwarding platforms.

My issue is people that don't understand these details
walk away from a comment like this and say "we can't
run netflow because it takes huge amounts of CPU
power" which clearly isn't always the case.

Rodney

> 
> -- 
>          Ryan O'Connell - CCIE #8174
> <ryan at complicity.co.uk> - http://www.complicity.co.uk
> 
> I'm not losing my mind, no I'm not changing my lines,
> I'm just learning new things with the passage of time
> 
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