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Do hosts send IGMP membership reports for multicast groups in the 224.0.0.0/24 range?

Sam Brynes
Level 1
Level 1

My guess is "no".

 

I connected a Cisco router to a switch and SPANed the port. I didn't see any IGMP membership reports for 224.0.0.1 or for 224.0.0.2.

 

On a related note, how do Cisco switches handle multicast for 224.0.0.0/24 any differently than for other multicast ranges if hosts do not send IGMP membership reports for 224.0.0.0/24? If they don't send IGMP membership reports for that range, my best guess is that a Cisco switch would flood all traffic destinted for 224.0.0.0/24 across all ports in the same VLAN on the switch (and any trunks that do not have that VLAN pruned).

1 Reply 1

Jon Marshall
Hall of Fame
Hall of Fame

 

They don't send membership reports for 224.0.0.1.

 

224.0.0.0/24 are flooded within the vlan and you cannot filter them using IGMP snooping or you couldn't the last time I looked at this which was a while ago. 

 

Jon

Review Cisco Networking products for a $25 gift card