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Spirent TestCenter: Is there a way to see packet size distribution on the RX port? Like how many packets were of size 128 - 144 bytes

Environment/Versions
 
  • Spirent TestCenter
  • Packet size distribution
  • Frame Length distribution

Is there a way to check on Spirent TestCenter RX port how many packets from each packet size / frame length were received?
 
Answer

For this task, Group histograms would be the way to go, however you should first check whether if the test module you are using supports it or not: FAQ19657 - Spirent TestCenter: How to know which Spirent TestCenter module supports Group Histograms?

Follow the procedure on the following KB aritcle for you to enable Group Histogram (Frame Length) and calibrate it (FAQ18705 - Spirent TestCenter: How to enable histogram mode on STC GUI)

enlightenedBe aware Spirent TestCenter will show you only 16 buckets, the calibration will create the buckets automatically, and you can not modify/adjust the bucket ranges created, so this is the best we can do.


I did a test using a simple configuration:
  • FX2-10G-S16 (That supports Group Histogram
  • 2 ports b2b
  • 1 Streamblock with random frame size from 128 to 144
  • Burst size = 15

We can see the Histogram Distribution on this way:
  • 1 frame with frame size >= 129 and < 131
  • 2 frame with frame size >= 131 and < 133
  • 4 frame with frame size >= 133 and < 134
  • 1 frame with frame size >= 135 and < 137
  • 2 frame with frame size >= 137 and < 139
  • 2 frame with frame size >= 139 and < 141
  • 2 frame with frame size >= 141 and < 143
  • 1 frame with frame size >= 143 and < 145
  • Total frames = 15
    • previous and following buckets were all 0

 

Doing a capture on port //3/2 we validated the capture matched with the Histogram groups on the GUI, 15 frame total, and group distributions are highlited using just 2 colors to separate each one from the next:
 


Find attached the .tcc configuration used for this sample as well as the .pcap
 

Product : Spirent TestCenter,Supported counters