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?
Just to expand a little on what Giuseppe describes for #3. . .
Switches without some kind of mutlicast control switches (or hubs) will forward multicast much like broadcast (as also mentioned in the OP). Also much like broacast, without routing support, they will not normally pass through a router.
Unlike broadcast, although host NICs will see all multicast packets (again assuming they are not suppressed by a switch), the host NIC will ignore multicast packets it's not interested in (much like unicast seen on hub port but without the host's address). (NB: IP mulitcast maps into blocks of Ethernet multicast, so Ethernet NICs can accept some muliticast they don't want [also again much like broadcast].)
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...