Multicast addresses are special IP addresses used to send data to multiple devices simultaneously. Instead of sending individual copies of the data to each device, a single multicast message is sent to a group of devices that have joined a specific multicast group. This method is efficient for applications like video conferencing and streaming, where the same content is delivered to many users at once. In the Internet Protocol version 4 (IPv4), multicast addresses range from 224.0.0.0 to 239.255.255.255. Devices that want to receive multicast messages must subscribe to a multicast group, allowing them to receive data sent to that address. This reduces network congestion and optimizes bandwidth usage.