VIAVI TestCenter: PX3-100G in 40G mode - Emulated Pause frames unable to meet the expected Latency.

• Test Scenario: • Customer test frames sizes from Min to Jumbo frames. For a frame size, change the pause quanta from 0 to 16000 • Test Pass Criteria: • Test Evaluate the differences between Max Latency – Min Latency and compare this differences with expected (calculated) values with applied Tolerances. If the test doesn’t meet the expected values with the applied Tolerance then the test fails. • For example: Pause quanta 2048 for 40G speed is 26.214us. So the Max-Min latency should be close to this value. • Failure happens for the Large Frame sizes like 9182, 9216, 9780 bytes when Pause Quanta is from 1024 … to 16000. The same 9780 bytes packet size barely passes with Pause quanta from 0,64, 256, and 512 . • Initial Investigation: • (Customer using the) Emulated Pause frames 15 FPS (64 Byte Pause) and changing the Quanta => recorded the Min and Max Latency , the Max Latency was lower than the expected values. • Created Raw Streamblock (Exactly as ED Pause) and Changing the Quanta => Recorded the Min and Max Latency, the Max Latency is much higher compare to Emulated Pause and also this exactly as expected.

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