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When a device send a messege to all possible receiver it is called broadcasting. This message is received by all other devices. Destination address of message contain all bits set to 1.

while when a device send a message to a group of devices it is called multicasting. Message is received by only devices which belongs to group mentioned in address field.

Brodcasting is used to send messages to all hosts of the same subnet even though there are no receiving processes. So, it is not efficient and waste resources of all systems. Which is used for router to detect linked system in a subnet.
Multicasting is used to send messages to a group of system which have at least one process who joined to this group.

Multicast- Send message to group of devices, not necessarily every device on your network
Broadcast- Send message to every device on your network

Hubs can only broadcast messages as they work at physical level of OSI model and thus does not understand MAC(Media Access Control) addresses.
Switch, however is also capable of multicasting as it works on the data link layer and can distinguish devices by their MAC addresses

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