Connectivity Guide

Unknown multicast ood control
The unknown multicast ood control feature enables the system to forward unknown multicast packets only to a multicast router
(mrouter).
When you enable multicast snooping, OS10 forwards multicast frames, whose destination is already learned, to their intended recipients.
When the system receives multicast frames whose destination is not known, it oods the frames for all ports on the specic VLAN. All
hosts that receive these multicast frames must process them. With multicast ood control, the system forwards unknown multicast frames
only to the interface that leads to the mrouter. The mrouter can then forward the trac to the intended destinations.
For multicast ood control to work, you must enable both IGMP and MLD snooping on the system. By default, multicast ood control,
IGMP snooping, and MLD snooping are enabled.
NOTE: The Multicast ood control feature is not supported on the Dell EMC Networking S4248FB-ON, S4248FBL-ON, and
S5148F-ON switches.
The following describes a scenario where a multicast frame is ooded on all ports of all switches. The switches and hosts in the network
need not receive these frames because they are not the intended destinations.
With multicast ood control, multicast frames, whose destination is not known, are forwarded only to the designated mrouter port. OS10
learns of the mrouter interface dynamically based on the interface where an IGMP membership query is received. You can also statically
congure the mrouter interface using the ip igmp snooping mrouter and ipv6 mld snooping mrouter commands.
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Multicast