What is Broadcasting and How it Works? - FMUSER

Radio is a term used when talking about radio and television transmission. The radio antenna or TV transmitter is sending a single signal, and anyone can receive the signal by radio within the signal range. It doesn't matter whether your radio is turned on or tuned to listen to that particular radio channel. Whether you choose to listen to the radio signal or not, the signal will reach your radio device.

The term broadcast is also used in computer networks and basically has the same meaning as radio or television broadcasting. A device such as a computer or a router sends a broadcast message on the local LAN to reach everyone else on the local LAN.

Here are two examples of when broadcasting can be used on a computer network:

A computer has just started and needs an IP address. It sends a broadcast message to try to locate the DHCP server to request an IP address. Since the computer has just started, it does not know whether there are any DHCP servers on the local LAN or the IP addresses that any such DHCP servers may have. Therefore, the computer will issue a broadcast that will reach all other devices on the LAN to request any available DHCP server to reply to an IP address.

Windows computers want to know which other windows computers are connected to the local LAN so that files and folders can be shared between computers. It automatically sends a broadcast over the LAN to locate any other windows computer.

When the computer issues a broadcast, it will use the special target MAC address FF: FF: FF: FF: FF: FF. This address is called a broadcast address and is used exclusively for this purpose. Then all other devices on the LAN will know that the traffic is broadcast to everyone else in the LAN.

Any computer, router or another device that receives a broadcast picks up the message to read the content. But not every device will become the intended recipient of traffic. Any device that reads a message just to notice that the message is not intended for them will simply discard the message after reading it.

In the above example, the computer is looking for a DHCP server to obtain an IP address. All other devices on the LAN will receive the message, but since they are not DHCP servers and cannot distribute any IP addresses, most of them will simply discard the message.

The home router has a built-in DHCP server and replies to announce itself to the computer and provide the IP address.