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Using IGMP but Multicast still Flooding

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  • 1.  Using IGMP but Multicast still Flooding

    Posted Aug 30, 2018 12:11 AM

    Hello everyone, Im new here.

    I want to ask about the multicast, 

    The first case is, I have switch HP 2530 24 port with 24 10/100 and 2 100/1000 NIC, And i have servers with bandwidth video multicast around 120-125Mbps. Servers plug into 2 gigabit NIC switch and the client into 10/100 NIC. Using IGMPv2 as the default.

    The problem is,

    1. When I set IGMP to mode AUTO the video is good and multicast not flooding to the client. But after 5-10 minutes the client stop receive multicast traffic.

    2. And I set IGMP to mode FORWARD, Client receive multicast trafiic and video NOT stopping after 5-10 minutes. But the problem is the client only have 10/100 NIC but multicast traffic send bandwidth around 120mbps, so when i start playing video, The video is Lagging.

     

    Any suggestion guys? maybe have a sollution for this problem?

     

    Thanks.



  • 2.  RE: Using IGMP but Multicast still Flooding
    Best Answer

    Posted Sep 05, 2018 03:47 AM

    Hey man!

     

    In your first case when using IGMP snooping, the switch will stop forward the multicast stream if it does not receive an IGMP report within a certain interval (probably 5 minutes in your case).

    Now, the clients does not report itself saying that it is still listening to the stream. 

    Therefore you need something called an IGMP querier in your network who is sending regular IGMP queries asking if anyone is still listening to a stream. The clients will then report it with an IGMP report and the underlying switches will take a note and refresh the expiration timer.

     

    This can be your core-switch and you can read about it here:

    http://h22208.www2.hpe.com/eginfolib/networking/docs/switches/WB/15-18/5998-8166_wb_2920_mrg/content/ch01s03.html

     

    I'm not sure if you need an IP address on the interface in your IGMP querier switch, but I think you might need it in your multicast VLAN.

     

    I hope this makes sense.