[c-nsp] 6509 + Netflow

[Ian Cox]

At 10:24 AM 10/8/2005 +0800, Jacky Chan wrote:
>Hi,
>  I want to setup Netflow to monitor traffic between two GE interfaces on my
>6509. The 6509 providing transit services and I want to know the traffic
>between AS#1 and AS#2.
>
>  This 6509 have two SUP-1A, MSFC+PFC, the hardware is rather old and running
>hybrid OS. The traffic between two GE interfaces around 800M.
>
>  The existing CPU utilization of the Supervisor and MSFC are 5% and 16%.
>
>  I have read some document and they mentioned Netflow is CPU/ Memory
>intensive, but the "Sampled Netflow" can help to decrease the CPU load a
>lot.
>
>  I have the following question in my brain, could you give me a hand?
>
>1. My existing hardware is safe to configure Netflow?

The hardware you have is flow based, so changing the flow mask from 
the default to full can result in increase CPU utilization. The 
default flow mask is destination IP, and to have useful netflow 
information you need it set to interface full. (Sup2 and Sup720 are 
CEF/FIB based so do not have this issue)

>2. Any tricks to configure Netflow?

Follow the instructions for the platform and your version of CatOS. Example:
http://www/en/US/products/hw/switches/ps708/products_configuration_guide_chapter09186a00801a5b29.html

>3. Go for Sampled Netflow?

Sampled netflow is only supported in IOS running on the switch and 
only for Sup2 and Sup720.


Ian

>4. Timebased Sampling or Random Sampling ?
>
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