Netflow On Copp Interface Support - Cisco Nexus 7000 Series Configuration Manual

Configuring NetFlow
With the F2 and F2e Series modules, you will need to be aware of the scaling factor to be configured,
Note
which is the additional sampling of 1:100 multiplied by the configured sampling. If you overlook this
factor, you will not see the actual in the reported rate.
Rate limiter limits the number of packets that reach the CPU to approximately 1000 packets per second on
the F2 and F2e Series modules. On the F3 Series module, rate limiting of 500 PPS per ASIC (SoC) is
implemented. Hence, for Cisco NX-OS 7000, if the F3 Series module has 6 SoCs, then it will rate limit
500*6=3000 PPS to the CPU, per F3 Series module; and for Cisco NX-OS 7700, if the F3 Series module has
12 SoCs, then it will rate limit 500*12=6000 PPS to the CPU, per F3 Series module.
The F3 and M3 Series module supports more sampling rate, 1:131071 compared to 1:8191 on other F2 and
F2e series modules.
The F3 series module supports an increased sampling rate on version 9. Performance on the F3 series
Note
module for the 7.2(0)D1(1) release has improved by 20 to 50 times the packet processing capability when
compared to a 6.2.x release. It is enhanced to 50000 pps. Due to the increased speed, you can use a lower
sampling rate on the F3 series module for this release. For example, a sampling of 1:4000 can be replaced
with a sampling of 1:80.
On M3 series modules, the default rate limit value is 8000 PPS per ASIC (SoC). In such a scenario, the Cisco
Nexus 7700 M3-Series 48-Port 1/10G Ethernet Module (with 2 SoCs) will rate limit 8000*2=16000 PPS only
to the CPU per M3 Series module. Use the hardware rate-limiter layer-2 netflow rate module m3module
command on a specific M3 Series module to configure the rate limit value to 24000 PPS. This configuration
will enable the M3 series module to rate limit 24000*2=48000 PPS to the CPU per M3 Series module.
Similarly, the Cisco Nexus 7700 M3-Series 24-Port 40G Ethernet Module (with 4 SoCs) will rate limit
8000*4=32000 PPS only to the CPU per M3 Series module. Use the hardware rate-limiter layer-2 netflow
rate module m3module command on a specific M3 Series module to configure the rate limit value to 12000
PPS. This configuration will enable the M3 Series module to rate limit 12000*4=48000 PPS to the CPU per
M3 Series module.
The following limitations apply to sampled NetFlow and F2 Series and F2e Series modules:
• An additional sampling of 1:100 is applied over the configured value for F2 Series and F2e Series
• The accuracy of the sampled NetFlow compared with the traditional NetFlow is dependent on the

Netflow on CoPP Interface Support

Netflow on CoPP Interface Support features enables application of Netflow on packets that are destined to
the supervisor module, which is the control plane.
Netflow on CoPP Interface Support feature enables the monitoring of packets that are egressing to the control
plane. This monitoring feature was added in NX-OS release 7.3(0)D1(1).
modules. For example, if the configured sampling is 1 in 200, the actual applied sampling is 1 in 20000.
When you configure the sampler value to 1:4956, the system does not start the rate-limiter. This value
is calculated based on the maximum traffic that would cross a module.
sampling rate configured. If the sampling rate is 1:1, the sampled NetFlow is exactly accurate as the
traditional NetFlow. And if the sampling rate is 1:100, the sampled NetFlow is less accurate than the
traditional, but it still yields statistical patterns that allow you to monitor the device.
Cisco Nexus 7000 Series NX-OS System Management Configuration Guide
Netflow on CoPP Interface Support
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