[c-nsp] Sup2T - poor netflow performance

"Rolf Hanßen" nsp at rhanssen.de
Fri Oct 18 10:51:08 EDT 2013

Hello Roland,

I already tried with single direction.
The load is lower but much higher than the same traffic on a Sup720-3B.
Input only still creates an average of ~20% cpu utilisation with less than
1 GBit live traffic.

I now added a sampling rate of 100:
sampler 1_to_100
 mode random 1 out-of 100

interface Vlan1421
 ip flow monitor <monitorname> sampler 1_to_100 input
 ip flow monitor <monitorname> sampler 1_to_100 output

This reduces cpu usage of the netflow processes to less than 5%, but it
looks to me that the exported data is not useful anymore (a stream with
double of the pps rate than everything else was not recognized by the
collector software).
Any other ideas ?

kind regards

> On Oct 18, 2013, at 12:13 PM, "Rolf Hanßen" <nsp at rhanssen.de> wrote:
>> ip flow monitor <monitorname> input
>> ip flow monitor <monitorname> output
> If you're collecting both ingress and egress NetFlow on the same
> interface, this could be contributing to your issues - Cisco do not
> recommend doing this due to overflow issues (which could lead to punting).
> Sampler configuration is covered in the Flexible NetFlow Command Reference
> for 15.x on cisco.com.
> And again, input ifindex should be obtained via 'match', not 'collect', in
> order to ensure that it's a key field.
> ---------------------------------
> Roland Dobbins <rdobbins at arbor.net>
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