A network condition in which so many broadcasts are occurring (for example, for address verification purposes) that normal communication is disrupted.
Broadcast storms commonly occur on Ethernet networks where baseband transmission technologies allow only one station to transmit at a time.
The presence of broadcast storms often indicates that a networking component is malfunctioning and is continually sending out broadcast messages.
A typical situation might be a failed transceiver on a network interface card (NIC) that is continually sending out a stream of binary «ones».
During a broadcast storm, the wire is continually busy and no other station is able to transmit information over the network - so broadcast storms essentially bring down the network. Since routers often are not configured to forward broadcast frames between subnets, broadcast storms usually are confined to a single subnet.
Broadcast storms might also indicate that the bandwidth of your network is nearly saturated and needs to be upgraded.