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VisionWorks Probe: Why do I get "Kfps exceeds limit. Retry later" when attempting capture from a 7521/7531/7524 probe with a filter and wrap buffer set to Yes?

Environment/Versions
VisionWorks Probe: 7521, 7531, 7524
Answer
All of the probes are limited to the number of frames per second they can process.  The TOTALKFPS setting in the output to RTRV-ATT-EQPT command shows the max limit for the probe.  Passive commands, such as MON-ETH-CAPTURE, do not know how many frames per second they are going to receive so the probe makes an estimate based on the AVGFRM_xxxx setting (for MON-ETH-CAPTURE the setting is AVGFRM_CAPTURE) that is set up in the RTRV-DB-IPTST output.

Example:
AVGFRM_CAPTURE = 64 (worst-case)
Access made with CIR of 10G

The result is: 
  10G / 8 / (64 + 20) = 14881 KFPS 
Which is the Max frame rate supported by a 10Gig unit.

When a capture is done with filters and wrap buffer set to yes, this adds additional stress to the processor and decreases performance.  To account for this the probe applies a penalty factor of approximately 1.3.  So in the example:
14881 KFPS * 1.3 = 19345 KFPS
As 19345 is greater than the max 14881, the test is not ran and error "Kfps exceeds limit. Retry later" is received.

What can be done to avoid getting the "KFPS error"?
Increase the AVGFRM_CAPTURE setting (recommended).
Decrease the CIR of your test.

It is very unlikely the average frame size being monitored is 64 bytes.  
What stresses the processor is the number of frames per second, not the number of bits per second. When frames are larger (e.g. 256-byte instead of 64-byte), the unit may be able to achieve full rate with no problems, because the frame rate will be lower.  

If use AVGFRM_CAPTURE = 256:
   10G / 8 / (256 + 20) = 4529 KFPS
   4529 KFPS * 1.3 = 5888 KFPS
As 5888 is less than the max 14881, the test will try to run.

In conclusion it is best to set up the AVGFRM_xxx settings to a value that represents the actual average frame size you expect in the network.

Product : VW Controller Virtual,VW Controller T&D Classic,VisionWorks Probe