Testing Multicasting with WireShark


Wireshark is a free IP testing tool from Wireshark.org. Download and install the app if you don’t have it already. There’s a great deal of information you can glean from a Wireshark network scan, but the following will focus on verifying IGMP multicasting setup and operation. I’m assuming you already know how to use VLC.

  • Launch Wireshark
  • Launch VLC and enter the same network stream used for the VLC test, or get ready to select channels from a QIP-D decoder
  • Click the Shark Fin icon at the top left to begin a network scan
  • Enter “igmp” in the line under the icons and click Enter on your keyboard.
  • Click Play in the VLC window, or turn on the QIP-D and select a channel when the unit has spooled up
  • Stop VLC or change channels on the QIP-D
  • This will show IGMP activity. The scan above shows:
    • One or more General Membership queries from network switch
    • A request from the VLC (the PC to join IGMP group and later on,
    • Membership Leave queries streams for 101 and 102
    • VLC sends a Leave response
  • This means that the encoders, decoders and switches are operating correctly.
  • You can stop the scan and save the results, if desired.