[c-nsp] Usage Billing w/ Netflow / Implementation Pitfalls

[Gert Doering]

Hi,

On Tue, May 20, 2008 at 02:03:19PM -0400, Chris Riling wrote:
>      I know this has been asked thousands of times before, but I don't think
> anyone has ever answered it in quite the same fasion. I'm thinking about
> turning on netflow on my border routers (7606's with Sup32's / full routes);
> Think I'll see any issues from turning on the exports? Also, specifically,
> we're looking to see the ability to generate reports for say, a /22, and the
> amount of transfer for each host in the /22 that has entered / exited our
> network at the border (MRTG on the switchports isn't going to cut it). 

As far as I know, netflow on the PFC3* cannot aggregate to /22 boundaries
- so you'll get lots of flows for individual IPs, and need to aggregate
in the collector machine.

I wonder why you're aiming that way, though.  

Why am I saying this?  We have a very nice and shiny netflow based 
accounting and billing system - and it takes *quite* some effort to 
maintain, and to construct the network in ways to keep it working ("do 
not overload the netflow engine on *this* router, do not plug together
those boxes *that* way, otherwise you'll get doubly-counted flows").

So we're actually trying to get rid of IP address based billing - and
move to "router interface based billing" (SNMP counters on SVI interfaces).

This, if done right, scales pretty much unbounded - as opposed to netflow,
which always hits some upper limit somewhere.

gert
-- 
USENET is *not* the non-clickable part of WWW!
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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de
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