Which two reasons explain why a server on VLAN 10 is unable to join a multicast stream that
originates on VLAN 20? (Choose two.)
A.
IGMP snooping and mrouter are not enabled on VLAN 10.
B.
VLAN 20 has no IGMP snooping querier defined and VLAN 10 has no mrouter.
C.
The mrouter on VLAN 20 does not see the PIM join.
D.
The mrouter must be on VLAN 10 and VLAN 20.
IGMP snooping is an optimization feature, so without it multicast traffic should still be passed.
This makes answers A and B unreasonable. Moreover IGMP snooping querier is needed if there is no multicast router. In our case there is no way to pass traffic from one VLAN to another without a router.
Answer C is tricky. There is no PIM join on VLAN 20 necessary as we have only source there.
But a multicast router with access to VLAN 20 will need a PIM join (on some other interface) to build multicast distribution tree. So the answer may be true.
Answer D is true. We will need some multicast router on VLAN 10 and some on VLAN 20 (may be the same).
I thing CD is correct.