Cloned from launchpad blueprint https://blueprints.launchpad.net/neutron/+spec/multicast-management.
In existing Open stack solution, Tenant VMs hosted will receive unnecessary
multicast traffic upto the Layer of the IP Stack even though they have not
subscribed to the multicast group. ( i.e multicast packets “reaches” the L2
layer of the VM’s will be dropped at the Layer 2 since no multicast entry
With this proposal, the vSwitch will be provisioned to handle IGMP control
packets to manage multicast data packets of the unreserved multicast
data group. The reserved multicast group traffic will be always allowed
which is required for proper functioning of the network.
Specification URL (additional information):