What will happen if multicast packet comes to router which doesn't have multicast enabled?
1) Multicast sender sends packet with its own unicast source address and destination multicast group address (this is correct?)
1a) Will router automaticly drop packet
1b) Will it treat it as a broadcast address?
2) From receiver to sender only goes unicast packets with unicast source and destination address , is this correct?
If IGMP join message comes to router that doesn't have multicast enabled will it:
2a) drop or
3) And on layer 2 network that doesn't have multicast enabled, multicast packets/frames will be treated as broadcast, because sender will automaticlly send frame with multicast MAC destination address. Is this correct?
a non multicast enabled router uses link local multicast addresses like 188.8.131.52 and 184.108.40.206 for OSPF but it cannot route multicast packets and ignores IGMP reports.
3) here some caution: if no multicast capable router is present and IGMP snooping is enabled multicast traffic is blocked.
some switches platforms allow to configure one switch as the igmp snooping querier and it will perform the IGMP queries like it was a multicast enabled router.
alternatively to this, IGMP snooping has to be disabled.
this can be done on a per vlan basis
Hope to help