Broadcast Types
Cisco routers support two different types of broadcasts: flooded and directed.
Flooded broadcasts are a broadcast for any subnet and use the IP address 255.255.255.255. A router does not propagate flooded broadcasts because they are considered local. When a host sends a packet to the IP address 255.255.255.255, the packet remains on the local subnet.
Directed broadcasts are for a specific subnet. Routers forward directed broadcasts. For example, a packet sent to the Class B address 129.30.255.255 would be a broadcast for network 129.30.0.0. The router would forward that packet to the identified network.