What is Broadcast?

There are 3 main methods of data transmission in IP networks: Unicast, Broadcast, Multicast. 

• Broadcast – the process of sending a packet from one host to all hosts on the network. 

• Due to the fact that the broadcast transmission type is used to send packets to all hosts on the network, the packets use a special broadcast IP address. When a host receives a packet with a broadcast address specified in the header as the recipient address, it processes the packet as if it were unicast.

• When a host needs to transmit some information to all hosts on the network, the broadcast data transmission method is used. Even when the address of special services or devices is unknown in advance, broadcast is also used for detection.

• Examples when broadcast data transmission is used:

1) Creating a map of the top-level addresses belonging to the lower ones.
2) Address request (example: ARP protocol)
3) Routing protocols exchange information about routes (RIP, EIGRP, OSPF)