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#17 Multicast improvement


Hi. I wanted to use iperf to make some testing on multicast traffic, but faced issues concerning 2 things:
- first, when you want to listen to a multicast group, you have to use -B option, so you cannot specify an interface on which you want to send multicast joins (through IGMP) and, as a consequence, you cannot specify on which interface you want to receive expected multicast traffic. I have to add here for clarity sake, that my server has 4 network interfaces, and that only one is connected to a dedicated multicast network.
- second, not sure if it is linked or not to my first problem, even if you cannot specify an interface on which you want to receive the multicast traffic, I didn't see IGMP join on the router facing the multicast receiver interface. The IGMP packet may have been sent on another interface, but I cannot confirm that or not.

Would it be possible to add a switch on the command line for the server side of iperf that would allow one to specify an interface (through an IP address for example) on which you want to receive traffic ? Can you also confirm or not that IGMP joins are sent to subscribe to a multicast group ?

Thanks a lot and best regards.


  • Wojtek Romek
    Wojtek Romek

    I agree that adding an option for specifying and interface for the server to listen for multicast would be really useful, and it would fix a problem i'm having. The problem is that under ubuntu 9.10 the server is not listening for multicast on an interface it should when i add static route But it does listen on a interface on which i have a default route..
    When googling for solution for my problem i found this post http://archive.ncsa.illinois.edu/lists/iperf-users/jan04/msg00003.html with ideas how to improve the multicast.