FAQ / Frequently Asked Questions

Would like to know the accurate timing of receiving/transmitting of the LAN packets.

You are able to know the transmitting/receiving timing of packets (interval time of packets) by the time stamp added on the measured data. However, it is possible the time stamp of LE-580FX TAP mode is affected by the capability of the PC (such as the capability of USB transferring) and different from the accurate time for about some μseconds. On the other hand, the time stamp of LE-580FX PG mode has the accurate time stamp with precision of ±1μs for 4th to 127th packets of measured data.

LE-580FX PG mode outputs the test packets at the specified transferring rate and able to know the reply and delay time. Capturing function on the PG mode measures Rx line with precision of  ±1μs. However, to measure Rx line and Tx line, you need to have a HUB with a port-mirroring function. Following are the example.

  1. Set the port-mirroring function on the HUB. (Read the manual of HUB.)
  2. Connect the target devices to the ports of HUB.
  3. Connect the mirror port of HUB and port A or B of LE-580FX.
  4. Open the LE-580FX Window and select PG function.
  5. From the menu bar, click “Capture”->”Window”->”PortA” or “PortB”. Open the Capture Window.
  6. Start measuring by clicking the start button.
  7. Measure the transmission/reception packets.
  8. Check the transmission/reception timing by the time stamp of 4th to 127th packets. The precision of this data should be ±1μs and there is a delay time of switching on the HUB.