VIAVI TestCenter: Why the RX frame count is larger than the TX?

VIAVI TestCenter: Why the RX frame count is larger than the TX?

  • When traffic is running: It is well known that traffic must be stopped for the counters to fully update, meanwhile, the traffic is running the calculations are on the fly and the counters are continuously changing, so calculations on the fly meant to be not accurate at all, and it is expected. However, in case you notice while the traffic running that sometimes RX>TX, here is the explanation: The port count updates are independent of each other, even within the same port, TX and RX counters may run on independent timers as well.Most likely the port count updates are periodical so one of the ports (let say Port X) will update with its latest number and then the other port (Let say Port Y) will update with it latest numbers, during that time Port X numbers will be greaterSince the port count updates are going Port X then Port Y then Port X and so on, it could be there will be a period of time when RX port numbers are newer than TX port numbers, it might be very short, or it might be noticeable.   • When traffic is stopped: If you find out tht the RX frame is more than TX frame on port counters, in most situation this is normal. Because port counter will record all frames that received including the frames from STC and DUT, which means some protocol packets will be counted as well. On the other hand, our detailed stream result count the frames with VIAVI signiture field only, so all framse from other device are not calculated. As a result you may find Port counters different with Stream counters.