avoid IP-multicast in your GNS3 labs!

Hey people!

Some days ago I ran into a major problem. Configured PIM dense mode on my virtual devices, everything looking fine. ICMP requests to the MCast groups were successful until…from one second to another it did not work anymore. My EIGRP adjacencies were flapping and I experienced packet loss. I could not say were the packet loss was sourced.

I described it here: http://ieoc.com/forums/t/18290.aspx 

There is a link on the web, where this trouble is described as well: http://ieoc.com/forums/t/3488.aspx

If you gained other experiences…tell me!


About markus.wirth

Living near Limburg in Germany, working as a Network Engineer around Frankfurt am Main.
This entry was posted in GNS3 / dynamips, Uncategorized. Bookmark the permalink.

5 Responses to avoid IP-multicast in your GNS3 labs!

  1. Interesting, thanks for this. I’ll also keep in mind the “workaround’ referenced, that involved disabling cef among other things …. which works, but also apparently disables other technologies that depend upon cef

  2. markus.wirth says:

    Okay didnt know about this workaround….sounds interesting.
    Some days ago I did a multicast lab again on gns3 and got strange things happening again…EIGRP did begin to flap for example. And the CPU wasnt used completely at all.

  3. Sean says:

    Hate to dig up an old thread, but I had this exact same issue today and racked my brains for a good few hours trying to figure it. Tried manually setting speed and duplex, messing with static ip mroute command, nothing worked. It’s good to know I’m not the only one with this issue. I’ve run through the scenario a few times and it seems I get M.cast replies all the way up until packets starting in the 30’s…thats when I start getting tops of drops and route flaps.

  4. Samir Sogay says:

    http://babaawesam.wordpress.com/2013/03/18/multicasting-with-gns3-and-virtualbox/ should be a good blog on multicasting on GNS3 and seeing it graphically as multicast is a video stream.

  5. anubisg1 says:

    I can confirm, as today, this bug still exist :((

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