I've following scenario
Upper computer on VLAN 10 is sending some multicast messages and lower computer on VLAN 10 sends IGMP join periodically.
Lets say MC address is 224.1.1.1
Now, computer on VLAN 20 is sending IGMP join to 224.1.1.1 (IGMP snooping is configured).
Would the data arrive to the computer on VLAN 20?
If so, is there some way to prevent that from happening?
Best Answer
VLANs logically break a switch into multiple, unconnected switches. There is no traffic between VLANs (layer-2), except through a router (layer-3).
By default, routers do not route multicast packets. Multicast routing is very different than unicast routing, and it must be specifically configured on all the routers between networks in order for multicast packets to be routed between networks.
In your example, there is no router, so there can be no traffic between the VLANs. Even if you had a router, the multicast traffic would not be routed between the VLANs unless you had configured the router to do multicast routing for that particular multicast group.