Question

Simple IP multicast forwarding

  • 3 July 2019
  • 2 replies
  • 263 views

Hello - I'm new to this, and I’m trying to conduct a simple test on a Summit X670 switch running EXOS 15.5. I want to use the UFTP program to send files from one Windows sender to multiple Ubuntu receivers. The program uses multicast for sending files. All computers are on the same switch, and since all ports are on the Default VLAN together, my understanding is that no configuration with PIM or MVR is needed. However, the multicast traffic isn't reaching the destinations, according to Wireshark.

Is there anything I might need to do on the switch to get it to forward the traffic? Are there any monitoring commands I can employ to debug this?

2 replies

Userlevel 3
If you have IGMP Snooping enabled on the VLAN (is by default enabled on XOS, at least in 22.x and 30.x versions) then your receivers must send IGMP Joins, which you should see by looking at the igmp members on the XOS. Only then the multicast will get forwarded out of those ports.
Or else you disable IGMP snooping on the VLAN, then the multicast will be flooded, but on all VLAN ports much like a broadcast.
Thanks for your message. I tried a number of things, and upgrading the switch to the latest software available for the model seems to have improved the situation.

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